Unconjugated
Based on the central role of the ubiquitin-proteasome system (UPS) in the degradation of cellular proteins, proteasome inhibition has been considered an attractive approach for anticancer therapy. Deubiquitinases (DUBs) remove ubiquitin conjugates from diverse substrates; therefore, they are essential regulators of the UPS. DUB inhibitors, especially the inhibitors of proteasomal DUBs are becoming a research hotspot in targeted cancer therapy. Previous studies have shown that metal complexes, such as copper and zinc complexes, can induce cancer cell apoptosis through inhibiting UPS function. Moreover, we have found that copper pyrithione inhibits both 19S proteasome-associated DUBs and 20S proteasome activity with a mechanism distinct from that of the classical 20S proteasome inhibitor bortezomib. In the present study, we reveal that (i) nickel pyrithione complex (NiPT) potently inhibits the UPS via targeting the 19S proteasome-associated DUBs (UCHL5 and USP14), without effecting on the 20S proteasome; (ii) NiPT selectively induces proteasome inhibition and apoptosis in cultured tumor cells and cancer cells from acute myeloid leukemia human patients; and (iii) NiPT inhibits proteasome function and tumor growth in nude mice. This study, for the first time, uncovers a nickel complex as an effective inhibitor of the 19S proteasomal DUBs and suggests a potentially new strategy for cancer treatment.
MicroRNAs (miRNAs) are small non-coding RNAs that participate in several cellular functions and tumour progression. A previous microarray study demonstrated that miR-135b is downregulated in prostate cancer (PCa) cells, but the role and molecular mechanism of miR-135b in the regulation of tumour metastasis remain to be elucidated. In the present study, significant downregulation of miR-135b in PCa tissues, compared with noncancerous tissues, was detected by reverse transcription-quantitative polymerase chain reaction. Furthermore, the expression of miR-135b was demonstrated to be associated with the pathological stage and the levels of total and free prostate-specific antigen (PSA) in PCa cells. In addition, signal transducer and activator of transcription 6 (STAT6) was identified as a target of miR-135b in PCa cells by luciferase activity and western blot assays. The upregulation of miR-135b in PCa cells led to reduced expression of STAT6 in the cytoplasm and nucleus of these cells, while the overexpression of miR-135b and knockdown of STAT6 were able to inhibit the migration and invasion abilities of PCa cells in vitro. Therefore, the results of the present study indicate that miR-135b suppresses tumour metastasis by targeting STAT6.
Transgenic expression of I-E molecules prevents diabetes in NOD mice. So far, the precise role of these non-classical MHC II molecules remains elusive. Here, we showed that transgenic expression of I-E(k) alpha 16 molecule in NOD mice selectively reduced Th17 cells in the thymus and pancreatic draining lymph nodes. The reduction in Th17 cells was associated with both attenuated IL-6 production and decreased activation of macrophages. Mechanistically, transgenic expression of the I-E molecule diminished expression of intracellular classical MHC II molecule and led to impaired TLR4-mediated signaling. In contrast to classical MHC II molecule, this non-classical MHC II molecule negatively regulates the inflammatory responses of macrophages. Altogether, our study reveals a novel regulatory role of I-E molecules in modulating inflammatory immune responses.
The rabies virus (RABV) glycoprotein (G) is the principal contributor to the pathogenicity and protective immunity of RABV. In a previous work, we reported that recombinant rabies virus Hep-dG, which was generated by reverse genetics to carry two copies of the G-gene, showed lower virulence than the parental virus rHep-Flury in suckling mice with a better immune protection effect. To better understand the mechanisms underlying rabies virus attenuation and the role of glycoprotein G, isobaric tags for relative and absolute quantitation (iTRAQ) was performed to identify and quantify distinct proteins. 10 and 111 differentially expressed proteins were obtained in rHep-Flury and Hep-dG infection groups, respectively. Selected data were validated by western blot and qRT-PCR. Bioinformatics analysis of the distinct protein suggested that glycoprotein over-expression in the attenuated RABV strain can induce activation of the interferon signaling. Furthermore, it may promote the antiviral response, MHC-I mediated antigen-specific T cell immune response, apoptosis and autophagy in an IFN-dependent manner. These findings might not only improve the understanding of the dynamics of RABV and host interaction, but also help understand the mechanisms underlying innate and adaptive immunity during RABV infection.
MicroRNAs (miRNAs or miRs) play a pivotal role in esophageal carcinogenesis either as oncogenes or as tumor suppressor genes. In the present study, we found that the expression level of miR-218 was significantly reduced in esophageal squamous cell carcinoma (ESCC) tissues and ESCC cell lines. Moreover, its expression was found to correlate with the clinicopathological stage of ESCC; miR-218 expression was lower in the stage III tissue samples than in the stage I and II tissue samples. Furthermore, the decreased expression of miR-218 was found to be associated with an enhanced ESCC cell proliferation and metastasis. Western blot analysis and luciferase reporter assay revealed that miR-218 decreased BMI1 expression by binding to the putative binding sites in its 3'-untranslated region (3'-UTR). The BMI1 mRNA expression levels were markedly increased and negatively correlated with the miR-218 expression level in the ESCC tissues. Functional analyses revealed that the restoration of miR-218 expression inhibited ESCC cell proliferation, migration and invasion and promoted apoptosis. The knockdown of BMI1 by siRNA showed the same phenocopy as the effect of miR-218 on ESCC cells, indicating that BMI1 was a major target of miR-218. In the present study, our findings confirm miR-218 as a tumor suppressor and identify BMI1 as a novel target of miR-218 in ESCC. Therefore, miR-218 may prove to be a useful biomarker for monitoring the initiation and development of ESCC, and may thus be an effective therapeutic target in ESCC.
The process of islet transplantation for treating type 1 diabetes has been limited by the high level of graft failure that may be overcome by locally delivering trophic factors to enhance engraftment. Regenerating islet-derived protein 3 alpha (Reg3α) is a pancreatic secretory protein, which functions as an antimicrobial peptide in control of inflammation and cell proliferation. In this study, to investigate whether Reg3α could improve islet engraftment, a marginal mass of syngeneic islets pretransduced with adenoviruses expressing Reg3α or control EGFP were transplanted under the renal capsule of streptozotocin-induced diabetic mice. Mice receiving islets with elevated Reg3α production exhibited significantly lower blood glucose levels (9.057 ± 0.59 mmol/l vs 13.48 ± 0.35 mmol/l, P < 0.05) and improved glucose-stimulated insulin secretion (1.80 ± 0.17 ng/ml vs 1.16 ± 0.16 ng/ml, P < 0.05) compared with control group. The decline of apoptotic events (0.57% ± 0.15% vs 1.06% ± 0.07%, P < 0.05) and increased beta-cell proliferation (0.70% ± 0.10% vs 0.36% ± 0.14%, P < 0.05) were confirmed in islet grafts overexpressing Reg3α by morphometric analysis. Further experiments showed that Reg3α production dramatically protected cultured islets and pancreatic beta-cells from cytokine-induced apoptosis and the impairment of glucose-stimulated insulin secretion. Moreover, exposure to cytokines led to the activation of MAPKs in pancreatic beta-cells, which was reversed by Reg3α overexpression in contrast to control group. These results strongly suggest that Reg3α could enhance islet engraftments through its cytoprotective effect and advance the therapeutic efficacy of islet transplantation.
Transplantation of human neural stem/progenitor cells (hNSCs) as a regenerative cell replacement therapy holds great promise. However, the underlying mechanisms remain unclear. We, here, focused on the interaction between hNSCs and allogeneic peripheral blood mononuclear cells (PBMCs) in a co-culture model. We found that hNSCs significantly decrease the CD3+ and CD8+ T cells, reduce the gamma delta T cells and increase the regulatory T cells, along with reduced pro-inflammatory cytokines and increased anti-inflammatory cytokines after co-culture. We also found that PBMCs, in turn, significantly promote the proliferation and differentiation of hNSCs. Our data suggest that hNSCs cross-talk with immune cells.
Oncolytic virotherapy is a growing treatment modality that uses replicating viruses as selective antineoplastic agents. Safety and efficacy considerations dictate that an ideal oncolytic agent would discriminate between normal and cancer cells on the basis of common genetic abnormalities in human cancers. Here, we identify a naturally occurring alphavirus (M1) as a novel selective killer targeting zinc-finger antiviral protein (ZAP)-deficient cancer cells. In vitro, in vivo, and ex vivo studies showed potent oncolytic efficacy and high tumor tropism of M1. We showed that the selectivity depends on ZAP deficiency by systematic identification. A large-scale multicenter pathology study using tissue microarrays reveals that ZAP is commonly deficient in human cancers, suggesting extensive application prospects for M1. Additionally, M1 killed cancer cells by inducing endoplasmic reticulum stress-mediated apoptosis. Our report provides novel insights into potentially personalized cancer therapy using oncolytic viruses.
Metastasis is one of the major causes of cancer-related death. It is a complex biological process involving multiple genes, steps, and phases. It is also closely connected to many biological activities of cancer cells, such as growth, invasion, adhesion, hematogenous metastasis, and lymphatic metastasis. Fucoidan derived from Undaria pinnatifida sporophylls (Ups-fucoidan) is a sulfated polysaccharide with more biological activities than other fucoidans. However, there is no information on the effects of Ups-fucoidan on tumor invasion and metastasis. We used the mouse hepatocarcinoma Hca-F cell line, which has high invasive and lymphatic metastasis potential in vitro and in vivo, to examine the effect of Ups-fucoidan on cancer cell invasion and metastasis. Ups-fucoidan exerted a concentration- and time-dependent inhibitory effect on tumor metastasis in vivo and inhibited Hca-F cell growth, migration, invasion, and adhesion capabilities in vitro. Ups-fucoidan inhibited growth and metastasis by downregulating vascular endothelial growth factor (VEGF) C/VEGF receptor 3, hepatocyte growth factor/c-MET, cyclin D1, cyclin-dependent kinase 4, phosphorylated (p) phosphoinositide 3-kinase, p-Akt, p-extracellular signal regulated kinase (ERK) 1/2, and nuclear transcription factor-κB (NF-κB), and suppressed adhesion and invasion by downregulating L-Selectin, and upregulating protein levels of tissue inhibitor of metalloproteinases (TIMPs). The results suggest that Ups-fucoidan suppresses Hca-F cell growth, adhesion, invasion, and metastasis capabilities and that these functions are mediated through the mechanism involving inactivation of the NF-κB pathway mediated by PI3K/Akt and ERK signaling pathways.
Numerous studies have established important roles for microRNAs (miRNAs) in regulating gene expression. Here, we report that miRNAs also serve as a surveillance system to repress the expression of nonsense mRNAs that may produce harmful truncated proteins. Upon recognition of the premature termination codon by the translating ribosome, the downstream portion of the coding region of an mRNA is redefined as part of the 3' untranslated region; as a result, the miRNA-responsive elements embedded in this region can be detected by miRNAs, triggering accelerated mRNA deadenylation and translational inhibition. We demonstrate that naturally occurring cancer-causing APC (adenomatous polyposis coli) nonsense mutants which escape nonsense-mediated mRNA decay (NMD) are repressed by miRNA-mediated surveillance. In addition, we show that miRNA-mediated surveillance and exon-exon junction complex-mediated NMD are not mutually exclusive and act additively to enhance the repressive activity. Therefore, we have uncovered a new role for miRNAs in repressing nonsense mutant mRNAs.
Apoptosis contributes to antitumor effect of Newcastle disease virus (NDV). Autophagy is a protective response under cellular stress including viral infection. How autophagy interferes with oncolysis of NDV remains unclear. In this study, we found that NDV La Sota strain induced autophagy and preserved autophagic flux in non-small cell lung cancer cells. NDV-induced autophagy promoted viral replication by blocking cancer cells from caspase-dependent apoptosis. Moreover, we found that NDV recruited SQSTM1-mediated mitophagy to control cytochrome c release, and thus blocked intrinsic pro-apoptotic signaling. Finally, we observed an enhanced oncolysis in NSCLC cells treated with NDV in the presence of an autophagy inhibitor 3-methyladenine (3-MA). Interestingly, a more profound antitumor effect could be achieved when administration of 3-MA was postponed to 24 h after NDV infection. Our findings unveil a novel way that NDV subverts mitophagy to favor its replication by blocking apoptosis, and provide rationale for systemic therapeutic cohort combining NDV with autophagy inhibitors in cancer therapy.
Metastasis-associated in colon cancer 1 (MACC1) is a newly identified gene that has been shown to promote tumor cell invasion and metastasis. The present study investigated the effect of MACC1 downregulation on the biological characteristics of the ovarian cancer OVCAR3 cell line. In this study, MACC1 expression was blocked using the RNA interference technique. The downregulation of MACC1 mRNA and protein expression was confirmed using quantitative polymerase chain reaction and western blot analysis. The proliferative activity and adhesion rate of the cells were detected using cell counting kit-8 and a cell adhesion assay, while cell invasion was determined using a Matrigel invasion assay and migration capacity was observed using migration and wound-healing assays. A tube formation assay was also used to examine the angiogenic capacity of cells, and a luciferase assay was performed to assess whether MACC1 binds to the c-MET gene. The MACC1 mRNA and protein expression levels were significantly downregulated using sequence-specific small interfering RNA (siRNA). The inhibition of MACC1 expression markedly decreased the invasive, metastatic and angiogenic capacities of the cells, but only slightly inhibited growth and adhesion. In addition, a putative MACC1-binding site was identified in the 3'-untranslated region of c-MET. MACC1-siRNA was also found to significantly reduce the expression of the c-MET protein and a luciferase reporter assay confirmed that c-MET was the target gene of MACC1. These results demonstrated that the attenuation of MACC1 suppresses cell invasion and migration and that MACC1 may regulate cell metastasis through targeting the expression of c-MET. Inhibition of the function of MACC1 may represent a new strategy for treating ovarian cancer.
Therapeutic applications of microRNAs (miRNAs) in RAS-driven glioma were valuable, but their specific roles and functions have yet to be fully elucidated. Here, we firstly report that miR-143 directly targets the neuroblastoma RAS viral oncogene homolog (N-RAS) and functions as a tumor-suppressor in glioma. Overexpression of miR-143 decreased the expression of N-RAS, inhibited PI3K/AKT, MAPK/ERK signaling, and attenuated the accumulation of p65 in nucleus of glioma cells. In human clinical specimens, miR-143 was downregulated where an adverse with N-RAS expression was observed. Furthermore, overexpression of miR-143 decreased glioma cell migration, invasion, tube formation and slowed tumor growth and angiogenesis in a manner associated with N-RAS downregulation in vitro and in vivo. Finally, miR-143 also sensitizes glioma cells to temozolomide (TMZ),the first-line drug for glioma treatment. Taken together, for the first time, our results demonstrate that miR-143 plays a significant role in inactivating the RAS signaling pathway through the inhibition of N-RAS, which may provide a novel therapeutic strategy for treatment of glioma and other RAS-driven cancers.
Proteasomes are attractive emerging targets for anti-cancer therapies. Auranofin (Aur), a gold-containing compound clinically used to treat rheumatic arthritis, was recently approved by US Food and Drug Administration for Phase II clinical trial to treat cancer but its anti-cancer mechanism is poorly understood. Here we report that (i) Aur shows proteasome-inhibitory effect that is comparable to that of bortezomib/Velcade (Vel); (ii) different from bortezomib, Aur inhibits proteasome-associated deubiquitinases (DUBs) UCHL5 and USP14 rather than the 20S proteasome; (iii) inhibition of the proteasome-associated DUBs is required for Aur-induced cytotoxicity; and (iv) Aur selectively inhibits tumor growth in vivo and induces cytotoxicity in cancer cells from acute myeloid leukemia patients. This study provides important novel insight into understanding the proteasome-inhibiting property of metal-containing compounds. Although several DUB inhibitors were reported, this study uncovers the first drug already used in clinic that can inhibit proteasome-associated DUBs with promising anti-tumor effects.
The successful development of bortezomib-based therapy for treatment of multiple myeloma has established proteasome inhibition as an effective therapeutic strategy, and both 20S proteasome peptidases and 19S deubiquitinases (DUBs) are becoming attractive targets of cancer therapy. It has been reported that metal complexes, such as copper complexes, inhibit tumor proteasome. However, the involved mechanism of action has not been fully characterized. Here we report that (i) copper pyrithione (CuPT), an alternative to tributyltin for antifouling paint biocides, inhibits the ubiquitin-proteasome system (UPS) via targeting both 19S proteasome-specific DUBs and 20S proteolytic peptidases with a mechanism distinct from that of the FDA-approved proteasome inhibitor bortezomib; (ii) CuPT potently inhibits proteasome-specific UCHL5 and USP14 activities; (iii) CuPT inhibits tumor growth in vivo and induces cytotoxicity in vitro and ex vivo. This study uncovers a novel class of dual inhibitors of DUBs and proteasome and suggests a potential clinical strategy for cancer therapy.
Proteins of the IQGAP family display complicated and often contradictory activities in tumorigenesis. IQGAP1 has well documented oncogenic potential and IQGAP2 has putative tumor-suppressive function. IQGAP3 is the latest addition to this family and its role in cancer development remains to be defined. Here we demonstrate IQGAP3 expression is markedly increased in lung cancer tissues at both mRNA and protein levels. Overexpression of IQGAP3 promoted tumor cell growth, and migration and invasion, whereas knockdown of IQGAP3 exhibited opposite effects. Moreover, suppression of IQGAP3 in a lung cancer cell line caused a reduction in the tumorigenicity of these cells in lung tissue after intravenous injection. Furthermore, we showed that IQGAP3 is able to interact with ERK1 and enhance its phosphorylation following treatment with EGF. These data suggest that IQGAP3 may contribute to the pathogenesis of lung cancer by modulating EGFR-ERK signaling.
The hominoid oncogene TBC1D3 enhances epidermal growth factor receptor (EGFR) signaling and induces cell transformation. However, little is known regarding its spatio-temporal regulation and mechanism of tumorigenesis. In the current study, we identified the microtubule subunit β-tubulin as a potential interaction partner for TBC1D3 using affinity purification combined with mass spectrometry analysis. The interaction between TBC1D3 and β-tubulin was confirmed by co-immunoprecipitation. Using the same method, we also revealed that TBC1D3 co-precipitated with endogenous α-tubulin, another subunit of the microtubule. In agreement with these results, microtubule cosedimentation assays showed that TBC1D3 associated with the microtubule network. The β-tubulin-interacting site of TBC1D3 was mapped to amino acids 286∼353 near the C-terminus of the TBC domain. Deletion mutation within these amino acids was shown to abolish the interaction of TBC1D3 with β-tubulin. Interestingly, the deletion mutation caused a complete loss of TBC1D3 from the cytoplasmic filamentous and punctate structures, and TBC1D3 instead appeared in the nucleus. Consistent with this, wild-type TBC1D3 exhibited the same nucleocytoplasmic distribution in cells treated with the microtubule depolymerizing agent nocodazole, suggesting that the microtubule network associates with and retains TBC1D3 in the cytoplasm. We further found that deficiency in β-tubulin-interacting resulted in TBC1D3's inability to inhibit c-Cbl recruitment and EGFR ubiquitination, ultimately leading to dysregulation of EGFR degradation and signaling. Taken together, these studies indicate a novel model by which the microtubule network regulates EGFR stability and signaling through tubulin dimer/oligomer interaction with the nucleocytoplasmic protein TBC1D3.
Epidermal growth factor (EGF) and insulin-like growth factor-I (IGF-I) are critical regulators of cell differentiation, survival, proliferation, and migration in cancers. This study found that ARNO (cytohesin-2), an activator of the EGF and IGF-I pathways, was more highly expressed in colorectal cancer tissue than in benign adjacent colorectal tissue. When ARNO-siRNA or the chemical inhibitor SecinH3 blocked ARNO, the downstream of the EGF and IGF-I pathways decreased in colorectal cell lines HT29 and HCT116. This blocking also weakened cell proliferation, invasion, and migration in vitro. Furthermore, EGF receptor (EGFR)-dependent colorectal tumor xenografts in nude mouse exerted anti-proliferative and growth suppression effects by injecting secineH3. These data suggested that inhibiting cytohesins or ARNO as cytoplasmic activators of EGFR and IGF-I in colorectal cancer resulted in anti-proliferation, reduced invasion, decreased migration, and suppressed growth in vivo and in vitro. Therefore, cytohesins or ARNO may be a potential therapy target for some colorectal cancer.
MicroRNAs (miRNAs) are a family of small RNA molecules that negatively regulate the expression of protein-coding genes and play critical roles in orchestrating diverse cellular processes. This regulatory mechanism is also exploited by viruses to direct their life cycle and evade the host immune system. Epstein-Barr virus (EBV) is an oncogenic virus that is closely associated with multiple human diseases, including nasopharyngeal carcinoma (NPC), which is a highly metastatic type of tumor and is frequently reported in South Asia. Several viral proteins have been found to promote the migration and invasiveness of NPC cells. However, not all tumor tissues express these viral oncoproteins, suggesting that other mechanisms may contribute to the aggressive behavior of NPC tumor cells. A previous sequencing study by our group revealed that the EBV miRNA miR-BART9 was expressed at high levels in all EBV-positive NPC tissues. In the present study, we used gain- and loss-of-function approaches to investigate the effect of miR-BART9 in EBV-negative and EBV-positive NPC cells. We discovered that miR-BART9 promotes the migration and invasiveness of cultured NPC cells. The promigratory activity observed in vitro was manifested as an enhanced metastatic ability in vivo. Computational analysis revealed that miR-BART9 may target E-cadherin, a membrane protein that is pivotal in preserving cell-cell junctions and the epithelial phenotype. Through biochemical assays and functional rescue analysis, we confirmed that miR-BART9 specifically inhibits E-cadherin to induce a mesenchymal-like phenotype and promote the migration of NPC cells. These results indicated that miR-BART9 is a prometastatic viral miRNA and suggested that high levels of miR-BART9 in EBV-positive NPC cells may contribute to the aggressiveness of tumor cells.
Inhibitor-of-apoptosis protein (IAP) inhibitors have been reported to synergistically reduce cell viability in combination with a variety of chemotherapeutic drugs via targeted cellular IAP (cIAP) depletion. Here, we found that cIAP silencing sensitised colorectal cancer (CRC) cells to selenite-induced apoptosis. Upon selenite treatment, the K63-linked ubiquitin chains on receptor-interacting protein 1 (RIP1) were removed, leading to the formation of the death-inducing complex and subsequent caspase-8 activation. Although the ubiquitinases cIAP1 and cIAP2 were significantly downregulated after a 24-h selenite treatment, cylindromatosis (CYLD) deubiquitinase protein levels were marginally upregulated. Chromatin immunoprecipitation assays revealed that lymphoid enhancer factor-1 (LEF1) dissociated from the CYLD promoter upon selenite treatment, thus abolishing suppression of CYLD gene expression. We corroborated these findings in a CRC xenograft animal model using immunohistochemistry. Collectively, our findings demonstrate that selenite caused CYLD upregulation via LEF1 and cIAP downregulation, both of which contribute to the degradation of ubiquitin chains on RIP1 and subsequent caspase-8 activation and apoptosis. Importantly, our results identify a LEF1-binding site in the CYLD promoter as a potential target for combinational therapy as an alternative to cIAPs.
Pancreatic cancer is one of the most lethal malignant diseases with the poorest prognosis and is the fourth leading cause of tumor-associated mortality in the industrialized world. microRNAs (miRNAs or miRs) are small noncoding RNAs of approximately 22 nucleotides long that are able to function as oncogenes or tumor suppressors in human cancer. In our study, overexpression of miR-203 in Panc-1 cells is sufficient to reduce migratory ability and invasiveness, and to induce upregulation of epithelial markers (Snail, ZO-1 and β-catenin) followed by a decrease of mesenchymal marker expression (Zeb-1, vimentin and fibronectin). We also found that the caveolin-1 mRNA or protein levels are modulated by miR-203 in Panc-1 cells. We found that exogenous miR-203 altered the level of cell migration and invasion, and the expression of associated proteins following caveolin-1 knockdown by small interfering RNA. These results demonstrate that miR-203 inhibits cell migration and invasion via caveolin-1 in pancreatic cancer cells, suggest that miR-203 expression may be a useful indicator of the metastatic potential and provide a new therapeutic target in this common malignancy.
Snail, a potent repressor of E-cadherin expression, plays a key role in epithelial-to-mesenchymal transition (EMT) in epithelial cancer. Recently, EMT and stemness programs are found linked together. In the current study, the expression of Snail and its contribution to cancer stem cell (CSC) marker expression, invasiveness, self-renewal, clonogenicity, and tumorigenicity of pancreatic cancer cells were studied. Our results showed that Snail was highly expressed in CSC(high) cell line Panc-1. Stable, short hairpin RNA (shRNA)-mediated Snail knockdown decreased invasion in Panc-1 cells, in line with increased E-cadherin expression and its translocation from the nucleus to the membrane. Snail silencing in Panc-1 also inhibited CSC marker ALDH expression, together with decreased sphere and colony forming capacity, which was highly consistent with the expression of stem cell associated transcription factors like Sox2 and Oct4. In mouse xenograft models, knockdown of Snail led to a reduced number of tumor-bearing mice and a reduced average size of tumors, which had a stronger membrane staining of E-cadherin and lighter staining of Oct4. Collectively, these findings implicate Snail is required for the maintenance of stem cell-like phenotype in pancreatic cancer, and inhibition of Snail could be an efficient strategy to treat pancreatic cancer by targeting CSCs.
The present study aims to investigate the pharmacological effect of the exopolysaccharides from Aphanothece halophytica GR02 (EPSAH) on the HeLa human cervical cancer cell line. HeLa cells were cultured in RPMI-1640-10% FBS medium containing with or without different concentrations of EPSAH. Cell viability was assessed by methylthiazol tetrazolium (MTT) assay. Cell apoptosis was elevated with Wright-Giemsa staining, AO/EB double staining, and DNA fragmentation assay. Apoptosis-associated molecules from cultured HeLa cells were quantified using Western blot analysis. Our results suggest that EPASH induces apoptosis in HeLa cells by targeting a master unfolded protein response (UPR) regulator Grp78. Grp78 further promotes the expression of CHOP and downregulates expression of survivin, which leads to activate mitochondria-mediated downstream molecules and p53-survivin pathway, resulting in caspase-3 activation and causing apoptosis. These findings provide important clues for further evaluating the potential potency of EPSAH for use in cancer therapy.
Ras homologue enriched in brain 1 (Rheb1) plays an important role in a variety of cellular processes. In this study, we investigate the role of Rheb1 in the post-natal heart. We found that deletion of the gene responsible for production of Rheb1 from cardiomyocytes of post-natal mice resulted in malignant arrhythmias, heart failure, and premature death of these mice. In addition, heart growth impairment, aberrant metabolism relative gene expression, and increased cardiomyocyte apoptosis were observed in Rheb1-knockout mice prior to the development of heart failure and arrhythmias. Also, protein kinase B (PKB/Akt) signaling was enhanced in Rheb1-knockout mice, and removal of phosphatase and tensin homolog (Pten) significantly prolonged the survival of Rheb1-knockouts. Furthermore, signaling via the mammalian target of rapamycin complex 1 (mTORC1) was abolished and C/EBP homologous protein (CHOP) and phosphorylation levels of c-Jun N-terminal kinase (JNK) were increased in Rheb1 mutant mice. In conclusion, this study demonstrates that Rheb1 is important for maintaining cardiac function in post-natal mice via regulation of mTORC1 activity and stress on the endoplasmic reticulum. Moreover, activation of Akt signaling helps to improve the survival of mice with advanced heart failure. Thus, this study provides direct evidence that Rheb1 performs multiple important functions in the heart of the post-natal mouse. Enhancing Akt activity improves the survival of infant mice with advanced heart failure.
Excessive βAR stimulation is an independent factor in inducing pathological cardiac hypertrophy. Here, we report miR-145 regulates both expression and localization of GATA6, thereby protecting the heart against cardiomyocyte hypertrophy induced by isoproterenol (ISO). The protective activity of miR-145 was associated with down-regulation of ANF, BNP and β-MHC expression, a decreased rate of protein synthesis, inhibited cardiomyocyte growth and the modulation of several signaling pathways including ERK1/2, JNK and Akt-GSK3β. The anti-hypertrophic effect was abrogated by exogenous over-expression of transcription factor GATA6 which was further identified as a direct target of miR-145. In addition, GSK3β antagonists, LiCl and TDZD8, restored the nuclear accumulation of GATA6, which was attenuated by miR-145 Finally, we observed a dynamic pattern of miR-145 expression in ISO-treated NRCMs and in the hearts of TAC mice. Together, our results identify miR-145 as an important regulator in cardiac hypertrophy.
Endothelial dysfunction participates in the development and progression of salt-sensitive hypertension. Asymmetric dimethylarginine (ADMA) is an endogenous inhibitor of nitric oxide synthase (NOS). The objectives of this study were to investigate the impact of a high salt diet on the PRMT/ADMA/DDAH (protein arginine methyltransferases; dimethylarginine dimethylaminohydrolase) pathway in Dahl salt-sensitive (DS) rats and SS-13BN consomic (DR) rats, and to explore the mechanisms that regulate ADMA metabolism independent of blood pressure reduction. Plasma levels of nitric oxide (NO) in DS rats given a high salt diet and subjected to intragastric administration of hydralazine (SH + HYD group) were lower than those given a normal salt diet (SN group). There were significant decreases in expression and activity of dimethylarginine dimethylaminohydrolase (DDAH) and endothelial NO synthase (eNOS) in DS rats given a high diet (SH group) in comparison to the SN group. The activity of DDAH and expression of eNOS in the SH + HYD group decreased more significantly than SN group. The mRNA expression of DDAH-1 and DDAH-2 were lowest in the SH group. The results suggest that salt, independent of blood pressure, can affect the PRMT-1/ADMA/DDAH system to a certain degree and lead to endothelial dysfunction in Dahl salt-sensitive rats.
AIM:
SMXZF (a combination of ginsenoside Rb1, ginsenoside Rg1, schizandrin and DT-13) derived from Chinese traditional medicine formula ShengMai preparations) is capable of alleviating cerebral ischemia-reperfusion injury in mice. In this study we used network pharmacology approach to explore the mechanisms of SMXZF in the treatment of cardio-cerebral ischemic diseases.
METHODS:
Based upon the chemical predictors, such as chemical structure, pharmacological information and systems biology functional data analysis, a target-pathway interaction network was constructed to identify potential pathways and targets of SMXZF in the treatment of cardio-cerebral ischemia. Furthermore, the most related pathways were verified in TNF-α-treated human vascular endothelial EA.hy926 cells and H2O2-treated rat PC12 cells.
RESULTS:
Three signaling pathways including the NF-κB pathway, oxidative stress pathway and cytokine network pathway were demonstrated to be the main signaling pathways. The results from the gene ontology analysis were in accordance with these signaling pathways. The target proteins were found to be associated with other diseases such as vision, renal and metabolic diseases, although they exerted therapeutic actions on cardio-cerebral ischemic diseases. Furthermore, SMXZF not only dose-dependently inhibited the phosphorylation of NF-κB, p50, p65 and IKKα/β in TNF-α-treated EA.hy926 cells, but also regulated the Nrf2/HO-1 pathway in H2O2-treated PC12 cells.
CONCLUSION:
NF-κB signaling pathway, oxidative stress pathway and cytokine network pathway are mainly responsible for the therapeutic actions of SMXZF against cardio-cerebral ischemic diseases.
AIMS:
Anemia of inflammation is quite prevalent in hospitalized patients with poor prognosis. Concerns about the effectiveness and safety of iron supplementation have arisen, driving the demand for alternative therapies. Induction of hepatic hepcidin, the master hormone of iron homeostasis, causes anemia under inflammatory conditions. Previous studies indicated that hydrogen sulfide (H2S), the third gasotransmitter and a well-known regulator of inflammation, may inhibit the secretion of inflammatory cytokines. We thus investigated the effect of H2S on inflammatory hepcidin induction.
RESULTS:
H2S suppressed lipopolysaccharide (LPS)-induced hepcidin production and regulated iron homeostasis in mice by decreasing serum interleukin-6 (IL-6) and Janus kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3) activation; similar results were obtained in Huh7 cells exposed to conditioned medium from LPS-challenged THP-1 macrophages. Intriguingly, we found H2S also attenuated hepcidin levels in Huh7 cells and mouse primary hepatocytes in a sirtuin 1 (SIRT1)-dependent manner. By promoting SIRT1 expression and stabilizing SIRT1-STAT3 interactions, H2S ameliorated IL-6-induced STAT3 acetylation, resulting in reduced hepcidin production. Inhibition and silencing of SIRT1 diminished H2S-mediated suppression of hepcidin, as opposed to SIRT1 activation and overexpression. Consistent results were observed in vivo. Furthermore, knockout of cystathionine γ-lyase (CSE), an endogenous H2S synthase, exaggerated inflammatory hepcidin expression in mice.
INNOVATION:
For the first time, we elucidated the effects and possible mechanisms of H2S on inflammatory hepcidin and established a novel regulatory link between SIRT1 and hepcidin.
CONCLUSION:
Our work demonstrates that H2S attenuates inflammation-induced hepatic hepcidin via multipathways and suggests new treatment strategies for anemia of inflammation.
Respiratory syncytial virus (RSV) is the leading cause of acute respiratory tract viral infection in infants, causing bronchiolitis and pneumonia. The host antiviral response to RSV acts via retinoic acid-inducible gene I (RIG-I). We show here that RSV infection upregulates major histocompatibility complex class I (MHC-I) expression through the induction of NLRC5, a NOD-like, CARD domain-containing intracellular protein that has recently been identified as a class I MHC transactivator (CITA). RSV infection of A549 cells promotes upregulation of NLRC5 via beta interferon (IFN-β) production, since the NLRC5-inducing activity in a conditioned medium from RSV-infected A549 cells was removed by antibody to IFN-β, but not by antibody to IFN-γ. RSV infection resulted in RIG-I upregulation and induction of NLRC5 and MHC-I. Suppression of RIG-I induction significantly blocked NLRC5, as well as MHC-I, upregulation and diminished IRF3 activation. Importantly, Vero cells deficient in interferon production still upregulated MHC-I following introduction of the RSV genome by infection or transfection, further supporting a key role for RIG-I. A model is therefore proposed in which the host upregulates MHC-I expression during RSV infection directly via the induction of RIG-I and NLRC5 expression. Since elevated expression of MHC-I molecules can sensitize host cells to T lymphocyte-mediated cytotoxicity or immunopathologic damage, the results have significant implications for the modification of immunity in RSV disease.
IMPORTANCE:
Human respiratory syncytial virus (RSV) is the leading cause of bronchiolitis and pneumonia in infants and young children worldwide. Infection early in life is linked to persistent wheezing and allergic asthma in later life, possibly related to upregulation of major histocompatibility class I (MHC-I) on the cell surface, which facilitates cytotoxic T cell activation and antiviral immunity. Here, we show that RSV infection of lung epithelial cells induces expression of RIG-I, resulting in induction of a class I MHC transactivator, NLRC5, and subsequent upregulation of MHC-I. Suppression of RIG-I induction blocked RSV-induced NLRC5 expression and MHC-I upregulation. Increased MHC-I expression may exacerbate the RSV disease condition due to immunopathologic damage, linking the innate immune response to RSV disease.
Copyright © 2015, American Society for Microbiology. All Rights Reserved.
BACKGROUND:
Several signal transduction pathways have been reported being involved in the acquisition of P-glycoprotein (P-gp) mediated multi-drug resistance (MDR) upon exposure to anti-cancer drugs, whereas there is evidence indicating that the expression and activity of P-gp were not equally or even reversely modulated by different drugs.
METHODS:
To further illustrate this drug-specific effect, possible mechanisms that enable breast cancer cells MCF-7 to acquire MDR to either paclitaxel (PTX) or doxorubicin (DOX) were investigated in a time-dependent manner.
RESULTS:
The results suggested that at least two pathways participated in this process. One was the short and transient activation of NF-κB, the second one was the relatively prolonged induction of PXR. Both PXR and NF-κB pathways took part in the PTX drug resistance acquisition, whereas DOX did not exert a significant effect on the PXR-mediated induction of P-gp. Furthermore, the property of NF-κB activation shared by DOX and PTX was not identical. An attempt made in the present study demonstrated that the acquired resistance to DOX was via or partially via NF-κB activation but not its upstream receptor TLR4, while PTX can induce the drug resistance via TLR4-NF-κB pathway.
CONCLUSIONS:
To our knowledge, this report is among the first to directly compare the time dependence of NF-κB and PXR pathways. The current study provides useful insight into the distinct ability of DOX and PTX to induce P-gp mediated MDR in breast cancer. Different strategies may be required to circumvent MDR in the presence of different anti-cancer drugs.
BACKGROUND:
Many studies support that chemokine (C-X-C motif) ligand 1 (CXCL1) regulate tumor epithelial-stromal interactions involving in tumor growth and invasion. However, limited studies have been conducted on the expression and function of the CXCL1 gene in hepatocellular carcinoma (HCC).
METHODS:
The mRNA and protein level expression of CXCL1 was examined in HCC tissues and cell lines. The expression of CXCL1 was correlated with clinicopathological features and follow-up data. Overexpression approaches were used to evaluate the biological functions of CXCL1 by MTT and matrigel invasion assays. Protein expression levels of CXCL1 and P65 were determined by western blot analysis.
RESULTS:
In this study, we found that CXCL1 expression was markedly upregulated in HCC tissues. Ectopic expression of CXCL1 significantly promoted HCC cells proliferation and invasion. Furthermore, CXCL1 promote cell invasion through NF-kB-dependent pathway. CXCL1 expression in HCC associated with clinical stage (P = 0.034) and distant metastasis (P = 0.028). Moreover, Patients with high CXCL1 expression level had poorer overall survival (OS;P = 0.027) than those with low CXCL1 expression.
CONCLUSIONS:
These data indicated that the CXCL1 upregulation may contribute to both the development and progression of HCC and this effect may be associated with increased proliferation and invasiveness mainly via regulating P65 expression.
BACKGROUND:
Inhibitors of DNA-binding (ID) proteins are known as important modulators in the regulation of cell proliferation and differentiation. This study sought to investigate the prognostic value of ID proteins in breast cancer.
METHODS:
The prognostic role of ID proteins in human breast cancer was investigated in 250 breast cancers, via tissue microarrays. The messenger (m)RNA and protein levels of E-cadherin were examined by quantitative reverse-transcription polymerase chain reaction (qRT-PCR) and Western blotting, in cells overexpressing IDs. Dual-luciferase report assay was used to investigate the potential mechanism, and a migration assay was performed to investigate the influence of IDs on cell migratory activity.
RESULTS:
The survival analysis with Kaplan-Meier and Cox regression showed that ID2 expression level, which correlated with estrogen receptor status and E-cadherin abundance, served as an independent prognostic factor for disease-free survival (DFS) (P=0.013). The prognostic value of ID2 for DFS was most significant in triple-negative breast cancer patients (P=0.009). We also found that ID2 was negatively correlated with E-cadherin expression by correlation analysis (P=0.020, Pearson's R=-0.155). Subsequently, we explored the biological rationale and uncovered that the enforced expression of ID proteins could suppress E-cadherin expression significantly, thus increasing the migration ability of mammary epithelial cells. Then using a combination of ID2 and E-cadherin expression, the patients were classified into four subgroups with different DFS (P=0.023).
CONCLUSION:
The overexpression of ID2 can be used as a prognostic marker in breast cancer patients, especially in triple-negative breast cancer patients. ID proteins were still, unexpectedly, revealed to inhibit E-cadherin abundance.
OBJECTIVES:
This study aims to investigate the effect of betulinic acid (BA) on myocardial ischemia reperfusion/injury in an open-chest anesthetized rat model.
METHODS:
The model was induced by 30 minutes left anterior descending occlusion followed by 2 hours reperfusion. There are six groups in our present study: sham operation group, ischemia/reperfusion group, low-dosage BA group, medium-dosage BA group, high-dosage BA group, and fosinopril sodium group. Rats in the latter four groups were administrated with BA (50, 100, and 200 mg/kg, i.g.) or fosinopril sodium (10 mg/kg, i.g.) once a day for 7 days before operation, respectively. Rats in the former two groups were given the same volume of vehicle (0.5% CMC-Na, i.g.). During the operation, cardiac function was continuously monitored. Serum LDH and CK were measured with colorimetric assays. The expression of Bcl-2 and Bax and the apoptosis of cardiomyocytes were investigated with western blot and TUNEL assay, respectively.
RESULTS:
Pretreatment with BA improved cardiac function and attenuated LDH and CK activities compared with IR group. Further investigation demonstrated that the expression of Bcl-2 and Bax and TUNEL assay was in line with the above results.
CONCLUSION:
BA may reduce the release of LDH and CK, prevent cardiomyocytes apoptosis, and eventually alleviate the extent of the myocardial ischemia/reperfusion injury.
AIM:
To explore the effect of sophocarpine on experimental liver fibrosis and the potential mechanism involved.
METHODS:
Sophocarpine was injected intraperitoneally in two distinct rat hepatic fibrosis models induced either by dimethylnitrosamine or bile duct ligation. Masson's trichrome staining, Sirius red staining and hepatic hydroxyproline level were used for collagen determination. Primary hepatic stellate cells (HSCs) were isolated and treated with different concentrations of sophocarpine. Real-time reverse transcription-polymerase chain reaction was used to detect the mRNA levels of fibrotic markers and cytokines. The expression of pathway proteins was measured by Western blot. The Cell Counting Kit-8 test was used to detect the proliferation rate of activated HSCs treated with a gradient concentration of sophocarpine.
RESULTS:
Sophocarpine decreased serum levels of aminotransferases and total bilirubin in rats under chronic insult. Moreover, administration of sophocarpine suppressed extracellular matrix deposition and prevented the development of hepatic fibrosis. Furthermore, sophocarpine inhibited the expression of α-smooth muscle actin (SMA), interleukin (IL)-6, transforming growth factor-β1 (TGF-β1), Toll-like receptor 4 (TLR4), and extracellular-related kinase (ERK) in rats. Sophocarpine also down-regulated the mRNA expression of α-SMA, collagen I, collagen III, TGF-β1, IL-6, tumor necrosis factor-α and monocyte chemoattractant protein-1, and decreased protein levels of TLR4, p-ERK, p-JNK, p-P38 and p-IKK in vitro after Lipopolysaccharide induction. In addition, sophocarpine inhibited the proliferation of HSCs accompanied by a decrease in the expression of Cyclin D1. The protein level of proliferating cell nuclear antigen was decreased in activated HSCs following a gradient concentration of sophocarpine.
CONCLUSION:
Sophocarpine can alleviate liver fibrosis mainly by inhibiting the TLR4 pathway. Sophocarpine may be a potential chemotherapeutic agent for chronic liver diseases.
BACKGROUND:
Pancreatic carcinoma possesses one of the highest lethality rates, highest drug-resistance, and highest incidence rates. The objective of this research was to enhance the efficacy and drug-resistance for pancreatic carcinoma by using inhibition of SIRT1 combined with gemcitabine therapy methods.
METHODS:
Three pancreatic carcinoma cells (PANC-1 cells, BxPC-3 cells, and SW1990 cells) received treatment with physiological saline, inhibition of SIRT1, gemcitabine, and combination therapy with inhibition of SIRT1 and gemcitabine in vitro; then BxPC-3 pancreatic cancer xenogeneic mice also received treatment with physiological saline, inhibition of SIRT1, gemcitabine, and combination therapy with inhibition of SIRT1 and gemcitabine in vivo.
RESULTS:
The cleaved poly ADP ribose polymerase (PARP)-1 effect of drug in pancreatic carcinoma cells was significantly different (P < 0.05) and the efficacy in descending order was the combination therapy with inhibition of SIRT1 and gemcitabine, inhibition of SIRT1, and gemcitabine. The BxPC-3 pancreatic cancer xenogeneic mice model received treatment with physiological saline, inhibition of SIRT1, gemcitabine, and combination therapy with inhibition of SIRT1 and gemcitabine in vivo and the results showed that the tumor volumes decreased and the survival rate within 45 days increased according to the order of the given drugs and the difference was significant (P < 0.05).
CONCLUSION:
Combination therapy with inhibition of SIRT1 and gemcitabine could improve efficacy and survival time in a BxPC-3 pancreatic cancer xenogeneic mice model, compared with single inhibition of SIRT1, or single gemcitabine therapy. The combination therapy method is a potential treatment method for pancreatic carcinoma.
Podocyte apoptosis is a major mechanism that leads to proteinuria in many chronic kidney diseases. However, the concert mechanisms that cause podocyte apoptosis in these kidney diseases are not fully understood. The Rho family of small GTPases has been shown to be required in maintaining podocyte structure and function. Recent studies have indicated that podocyte-specific deletion of Cdc42 in vivo, but not of RhoA or Rac1, leads to congenital nephrotic syndrome and glomerulosclerosis. However, the underlying cellular events in podocyte controlled by Cdc42 remain unclear. Here, we assessed the cellular mechanisms by which Cdc42 regulates podocyte apoptosis. We found that the expression of Cdc42 and its activity were significantly decreased in high glucose-, lipopolysaccharide- or adriamycin-injured podocytes. Reduced Cdc42 expression in vitro and in vivo by small interfering RNA and selective Cdc42 inhibitor ML-141, respectively, caused podocyte apoptosis and proteinuria. Our results further demonstrated that insufficient Cdc42 or Nwasp, its downstream effector, could decrease the mRNA and protein expression of YAP, which had been regarded as an anti-apoptosis protein in podocyte. Moreover, our data indicated that the loss of stress fibers caused by Cdc42/Nwasp deficiency also decreased Yes-associated protein (YAP) mRNA and protein expression, and induced podocyte apoptosis. Podocyte apoptosis induced by Cdc42/Nwasp/stress fiber deficiency was significantly inhibited by overexpressing-active YAP. Thus, the Cdc42/Nwasp/stress fibers/YAP signal pathway may potentially play an important role in regulating podocyte apoptosis. Maintaining necessary Cdc42 would be one potent way to prevent proteinuria kidney diseases.
Chronic opioid abusers are more susceptible to bacterial and viral infections, but the molecular mechanism underlying opioid-induced immunosuppression is unknown. MicroRNAs (miRNAs) are emerging as key players in the control of biological processes, and may participate in immune regulation. In this study, we investigated the molecular mechanisms in opioid-induced and miRNA-mediated immunosuppression, in the context of miRNA dysregulation in opioid abusers. Blood samples of heroin abusers were collected and analyzed using miRNA microarray analysis and quantitative PCR validation. The purified primary human monocytes were cultured in vitro to explore the underlying mechanism. We found that morphine and its derivative heroin significantly decreased the expression levels of miR-582-5p and miR-590-5p in monocytes. cAMP response element-binding protein 1 (CREB1) and CREB5 were detected as direct target genes of miR-582-5p and miR-590-5p, respectively, by using dual-luciferase assay and western bolt. Functional studies showed that knockdown of CREB1/CREB5 increased tumor necrosis factor alpha (TNF-α) level and enhanced expression of phospho-NF-κB p65 and NF-κB p65. Our results demonstrated that miR-582-5p and miR-590-5p play important roles in opioid-induced immunosuppression in monocytes by targeting CREB1/CREB5-NF-κB signaling pathway.
LF11-322 (PFWRIRIRR-NH2) (PFR peptide), a nine amino acid-residue peptide fragment derived from human lactoferricin, possesses potent cytotoxicity against bacteria. We report here the discovery and characterization of its antitumor activity in leukemia cells. PFR peptide inhibited the proliferation of MEL and HL-60 leukemia cells by inducing cell death in the absence of the classical features of apoptosis, including chromatin condensation, Annexin V staining, Caspase activation and increase of abundance of pro-apoptotic proteins. Instead, necrotic cell death as evidenced by increasing intracellular PI staining and LDH release, inducing membrane disruption and up-regulating intracellular calcium level, was observed following PFR peptide treatment. In addition to necrotic cell death, PFR peptide also induced G0/G1 cell cycle arrest. Moreover, PFR peptide exhibited favorable antitumor activity and tolerability in vivo. These findings thus provide a new clue of antimicrobial peptides as a potential novel therapy for leukemia.
Cranial irradiation-induced inflammation plays a critical role in the initiation and progression of radiation-induced brain injury (RIBI). Anti-inflammation treatment may provide therapeutic benefits. Corilagin (beta-1-O-galloyl-3, 6-(R)-hexahydroxydiphenoyl-D-glucose, C27H22O18) was a novel member of the tannin family with anti-inflammatory properties and is isolated from some medicinal plants, such as Phyllanthus amarus and Caesalpinia coriaria. In this study, the effect of Corilagin on RIBI was investigated and the underlying mechanisms were explored. Spatial learning and memory ability of mice were investigated by the Morris water maze test. Evans blue leakage and electron microscopy were used to assess the integrity of blood-brain barrier (BBB). The mRNA and protein expressions of inflammatory cytokines, TNF-α and IL-1β, were measured by using real-time PCR and Western blotting. The activation of microglial cells and expression of TNF-α were examined by immunofluorescence staining. Phosphorylated signal transducers and activators of transcription 3 (p-STAT3) and IκBα, and the translocation of p65 from cytoplasm to nucleus were detected by using Western blotting. Morris water maze test showed that Corilagin ameliorated the neurocognitive deficits in RIBI mice. Evans blue leakage and electron microscopy exhibited that Corilagin partially protected the BBB integrity from cranial irradiation-caused damage; immunofluorescence staining showed that Corilagin could inhibit microglial activation and TNF-α expression. Real-time PCR and Western blotting revealed that Corilagin downregulated the expression of TNF-α and IL-1β and inhibited the irradiation-induced activation of NF-κB pathways by upregulating p-STAT3 expression. In conclusion, Corilagin could attenuate RIBI through inhibiting microglial activation and the expressions of inflammatory cytokines. Corilagin might inhibit the activation of NF-κB pathway in a STAT3-associated manner, thereby downregulating the inflammatory cytokine expressions.
EGFR-targeted cancer therapy is a breakthrough in non-small cell carcinoma. miRNAs have been proved to play important roles in cancer. Currently, for the role of miRNAs in EGFR-targeted cancer therapy is unclear. In this study, first we found that erlotinib reduced the expression of miR-9. MiR-9 expression was increased in human lung cancer tissues compared with peripheral normal tissues, and miR-9 promoted the growth of NSCLC cells. Overexpression of miR-9 decreased the growth inhibitory effect of erlotinib. Second, miR-9 decreased FoxO1 expression by directly inhibition of its mRNA translation. Adenovirus-mediated overexpression of FoxO1 or siRNA-mediated downregulation of FoxO1 negatively regulated cell growth. And exogenous overexpression FoxO1 reduced the pro-growth effect of miR-9. Finally, we found that erlotinib upregulated FoxO1 protein expression. Moreover, overexpression of miR-9 decreased erlotinib-induced FoxO1 expression, and overexpression of FoxO1 enhanced the growth inhibitory effects of erlotinib. Additionally, we found that erlotinib downregulates miR-9 expression through suppressing the transcrption of miR-9-1 and enhanced DNA methylation maybe involved. These findings suggest that oncogenic miR-9 targeted FoxO1 to promote cell growth, and downregulation of this axis was involved in erlotinib's growth inhibitory effects. Clarifying the regulation of miRNAs by erlotinib may indicate novel strategies for enhancing EGFR-targeted cancer therapy.
This work aims to evaluate the anti-neuroinflammatory effects of natural sesquiterpene dimer caruifolin D from Artemisia absinthium L., which is an edible vegetable or traditional medicinal food in East Asia due to its sedation, anti-asthma and antipruritic effects. In this study, we reported that caruifolin D significantly inhibited the productions of various neuroinflammatory mediators from microglia in response to bacterial lipopolysaccharide stimulation. Moreover, anti-inflammatory mechanism study showed that caruifolin D markedly suppressed the production of intracellular reactive oxygen species, which was an important player involved in neuroinflammation, leading to inhibitory effects on the activations of protein kinase C (PKC) and c-Jun N-terminal kinase (JNK), which were two major neuroinflammatory signaling pathways in the brains. Furthermore, caruifolin D protected neurons against microglia-mediated neuronal inflammatory damages by up-regulating neuronal viability and maintaining healthy neuronal morphology. Taken together, these results expanded our knowledge about the anti-neuroinflammatory and neuroprotective mechanism of Artemisia absinthium L., and also suggested that caruifolin D was a major anti-inflammatory component from Artemisia absinthium L., which might be developed as a drug candidate for neuroinflammation-related diseases.
Rhizoma Paridis saponins (RPS), as steroid saponins, are the main components in Paris polyphylla. Curcumin (diferuloylmethane) is the most important component in the spice turmeric. In our previous research, RPS exhibited side effects such as nausea, vomiting, diarrhea, and so forth. Combination with curcumin not only alleviated the toxicity and gastric stimulus induced by RPS, but also improved the quality life of mice bearing tumor cells and enhanced their anticancer effect. This study evaluated subchronic toxicity of 45th dietary of RPS and curcumin on histopathology, biochemistry, and antioxidant index. As a result, RPS-treatment caused a slight liver injury (the elevation of serum AST, alkaline phosphatase (AKP), alanine transaminase (ALT), and gamma glutamyl transpeptidase (γ-GT), histopathological changes in liver section), oxidative stress (the enhancement of reactive oxygen species (ROS), malondialdehyde (MDA), and 8-hydroxy-2-deoxyguanosine (8-OHdG), separation of thioredoxin (Trx) and thioredoxin-interacting protein (TXNIP), but enhancement of heme oxygenase-1 (HO-1), glutathione S-transferase (GST), and nuclear factor-regulated factor 2 (Nrf2)), and inflammation (up-regulation of cyclooxygenase-2 (COX-2), interleukin-1β (IL-1β), and nuclear factor kappaB (NF-κB)). However, these changes were alleviated through co-treatment with curcumin. In conclusion, our work provided useful data for further research and new drug exploration of RPS and curcumin.
© 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 1935-1943, 2016.
GL-V9, a new synthesized flavonoid derivative, has been reported to possess anti-cancer properties in our previous studies. Uncontrolled overproduction of reactive oxygen species (ROS) has been implicated in oxidative damage of inflammatory bowel disease (IBD). In this study, we aimed to investigate the protective effect of GL-V9 against dextran sulfate sodium (DSS)-induced colitis. GL-V9 attenuated DSS-induced body weight loss, colon length shortening and colonic pathological damage. GL-V9 also inhibited inflammatory cells infiltration and decreased myeloperoxidase (MPO) and inducible nitric oxide synthase (iNOS) activities. Moreover, GL-V9 inhibited ROS and malondialdehyde (MDA) generation, but enhanced superoxide dismutase (SOD), glutathione (GSH) and total antioxidant capacity. GL-V9 reduced pro-inflammatory cytokines production in serum and colon as well. Mechanically, GL-V9 could increase Trx-1 via activation of AMPK/FOXO3a to suppress DSS-induced colonic oxidative stress. Furthermore, GL-V9 decreased pro-inflammatory cytokines and ROS production and increased the antioxidant defenses in the mouse macrophage cells RAW264.7 by promoting Trx-1 expression. In conclusion, our study demonstrated that GL-V9 attenuated DSS-induced colitis against oxidative stress by up-regulating Trx-1 via activation of AMPK/FOXO3a pathway, suggesting that GL-V9 might be a potential effective drug for colitis.
Perivascular adipose tissue (PVAT) has been recognized as an active contributor to vascular function due to its paracrine effects on cells contained within vascular wall. The present study was designed to investigate the effect of diosgenin on adipokine expression in PVAT with emphasis on the regulation of endothelial function. Palmitic acid (PA) stimulation induced inflammation and dysregulation of adipokine expression in PVAT. Diosgenin treatment inhibited IKKβ phosphorylation and downregulated mRNA expressions of proinflammatory cytokines/proteins including tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), monocyte chemoattractant protein (MCP-1), and inducible nitric oxide synthase (iNOS), while reduced gene expressions for adiponectin, PPARγ, and arginase 1 (Arg-1) were reversed by diosgenin treatment. Diosgenin enhanced AMPK phosphorylation under basal and inflammatory conditions in PVAT, whereas knockdown of AMPK by SiRNA diminished its modulatory effect, indicating that diosgenin inhibited inflammation in an AMPK-dependent manner. We prepared conditioned medium from PA-stimulated PVAT to induce endothelial dysfunction and found that pre-treatment of PVAT with diosgenin effectively restored the loss of ACh-induced vasodilation and increased eNOS phosphorylation in rat aorta. High-fat diet feeding in rats induced inflammation in PVAT and the impairment of endothelium-dependent vasodilation, whereas these alterations were prevented by oral administration of diosgenin at doses of 20 and 40 mg/kg. In conclusion, the obtained data showed that diosgenin ameliorated inflammation-associated adipokine dysregulation, and thereby prevented endothelial dysfunction. Our findings would shed a novel insight into the potential mechanism by which diosgenin protected endothelial function against inflammatory insult.
Chronic airway diseases are characterized by airway remodeling which is attributed partly to the proliferation and migration of airway smooth muscle cells (ASMCs). ATP-sensitive potassium (KATP) channels have been identified in ASMCs. Mount evidence has suggested that KATP channel openers can reduce airway hyperresponsiveness and alleviate airway remodeling. Opening K(+) channels triggers K(+) efflux, which leading to membrane hyperpolarization, preventing Ca(2+)entry through closing voltage-operated Ca(2+) channels. Intracellular Ca(2+) is the most important regulator of muscle contraction, cell proliferation and migration. K(+) efflux decreases Ca(2+) influx, which consequently influences ASMCs proliferation and migration. As a KATP channel opener, iptakalim (Ipt) has been reported to restrain the proliferation of pulmonary arterial smooth muscle cells (PASMCs) involved in vascular remodeling, while little is known about its impact on ASMCs. The present study was designed to investigate the effects of Ipt on human ASMCs and the mechanisms underlying. Results obtained from cell counting kit-8 (CCK-8), flow cytometry and 5-ethynyl-2'-deoxyuridine (EdU) incorporation showed that Ipt significantly inhibited platelet-derived growth factor (PDGF)-BB-induced ASMCs proliferation. ASMCs migration induced by PDGF-BB was also suppressed by Ipt in transwell migration and scratch assay. Besides, the phosphorylation of Ca(2+)/calmodulin-dependent kinase II (CaMKII), extracellular regulated protein kinases 1/2 (ERK1/2), protein kinase B (Akt), and cyclic adenosine monophosphate (cAMP) response element binding protein (CREB) were as well alleviated by Ipt administration. Furthermore, we found that the inhibition of Ipt on the PDGF-BB-induced proliferation and migration in human ASMCs was blocked by glibenclamide (Gli), a selective KATP channel antagonist. These findings provide a strong evidence to support that Ipt antagonize the proliferating and migrating effects of PDGF-BB on human ASMCs through opening KATP channels. Altogether, our results highlighted a novel profile of Ipt as a potent option against the airway remodeling in chronic airway diseases.
Oncogenic transcription factors are known to mediate the conversion of somatic cells to tumour or induced pluripotent stem cells (iPSCs). Here we report c-Jun as a barrier for iPSC formation. c-Jun is expressed by and required for the proliferation of mouse embryonic fibroblasts (MEFs), but not mouse embryonic stem cells (mESCs). Consistently, c-Jun is induced during mESC differentiation, drives mESCs towards the endoderm lineage and completely blocks the generation of iPSCs from MEFs. Mechanistically, c-Jun activates mesenchymal-related genes, broadly suppresses the pluripotent ones, and derails the obligatory mesenchymal to epithelial transition during reprogramming. Furthermore, inhibition of c-Jun by shRNA, dominant-negative c-Jun or Jdp2 enhances reprogramming and replaces Oct4 among the Yamanaka factors. Finally, Jdp2 anchors 5 non-Yamanaka factors (Id1, Jhdm1b, Lrh1, Sall4 and Glis1) to reprogram MEFs into iPSCs. Our studies reveal c-Jun as a guardian of somatic cell fate and its suppression opens the gate to pluripotency.
Sanhua decoction (SHD) is a famous classic Chinese herbal prescription for ischemic stroke, and aquaporin 4 (AQP4) is reported to play a key role in ischemic brain edema. This study aimed to investigate neuroprotection of SHD against focal cerebral ischemia/reperfusion (I/R) injury in rats and explore the hypothesis that AQP4 probably is the target of SHD neuroprotection against I/R rats. Lentiviral-mediated AQP4-siRNA was inducted into adult male Sprague-Dawley rats via intracerebroventricular injection. The focal cerebral ischemia/reperfusion model was established by occluding middle cerebral artery. Neurological examinations were performed according to Longa Scale. Brain water content, was determined by wet and dry weight measurement. Western blot was adopted to test the AQP4 expression in ipsilateral hippocampus. After the treatment, SHD alleviated neurological deficits, reduced brain water content and downregulated the expression of AQP4 at different time points following I/R injury. Furthermore, neurobehavioral function and brain edema after I/R were significantly attenuated via downregulation of AQP4 expression when combined with AQP4-siRNA technology. In conclusion, SHD exerted neuroprotection against focal cerebral I/R injury in rats mainly through a mechanism targeting AQP4.
Ilexgenin A is a natural triterpenoid with beneficial effects on lipid disorders. This study aimed to investigate the effects of ilexgenin A on endothelial homeostasis and its mechanisms. Palmitate (PA) stimulation induced endoplasmic reticulum stress (ER stress) and subsequent thioredoxin-interacting protein (TXNIP)/NLRP3 inflammasome activation in endothelial cells, leading to endothelial dysfunction. Ilexgenin A enhanced LKB1-dependent AMPK activity and improved ER stress by suppression of ROS-associated TXNIP induction. However, these effects were blocked by knockdown of AMPKα, indicating AMPK is essential for its action in suppression of ER stress. Meanwhile, ilexgenin A inhibited NLRP3 inflammasome activation by down-regulation of NLRP3 and cleaved caspase-1 induction, and thereby reduced IL-1β secretion. It also inhibited inflammation and apoptosis exposed to PA insult. Consistent with these results in endothelial cells, ilexgenin A attenuated ER stress and restored the loss of eNOS activity in vascular endothelium, and thereby improved endothelium-dependent vasodilation in rat aorta. A further analysis in high-fat fed mice showed that oral administration of ilexgenin A blocked ER stress/NLRP3 activation with reduced ROS generation and increased NO production in vascular endothelium, well confirming the beneficial effect of ilexgenin A on endothelial homeostasis in vivo. Taken together, these results show ER stress-associated TXNIP/NLRP3 inflammasome activation was responsible for endothelial dysfunction and ilexgenin A ameliorated endothelial dysfunction by suppressing ER-stress and TXNIP/NLRP3 inflammasome activation with a regulation of AMPK. This finding suggests that the application of ilexgenin A is useful in the management of cardiovascular diseases in obesity.
To investigate the influence of maternal dietary fat intake on the fatty acid composition and lipid metabolism of progeny subcutaneous fat (SQ), fourteen sows were randomly assigned to a control or high fat (HF) group which received a diet containing 8% corn oil starting seven days before farrowing until weaning. The results showed the fatty acid composition in progeny SQ at weaning age generally demonstrated a similar pattern with the sow milk. However, this pattern was not observed at the finishing stage. The stearoyl-CoA desaturase 1 mRNA and protein levels in the progeny SQ of the HF group decreased at both sampling stages when compared with controls. The study demonstrated that maternal dietary fat during lactation significantly affected the fatty acid composition of progeny SQ at the weaning stage, yet no obvious lasting effect was observed in progeny SQ at the finishing stage.
Prolonged hyperglycemia is an important risk factor of the pathogenesis of diabetic retinopathy (DR). Extracellular matrix molecules, such as fibronectin, collagen IV, and laminin, are associated with fibrotic membranes. In this study, we investigated the expression of fibronectin, collagen IV, and laminin in RPE cells under high glucose conditions. Furthermore, we also detected the phosphorylation of protein kinase B (Akt) under high glucose conditions in RPE cells. Our results showed that high glucose upregulated fibronectin, collagen IV, and laminin expression, and activated Akt in RPE cells. We also found that pretreatment with LY294002 (an inhibitor of phosphatidylinositol 3-kinase) abolished high glucose-induced expression of fibronectin, collagen IV, and laminin in RPE cells. Thus, high glucose induced the expression of fibronectin, collagen IV, and laminin through PI3K/Akt signaling pathway in RPE cells, and the PI3K/Akt signaling pathway may contribute to the formation of fibrotic membrane during the development of DR.
Second heart field (SHF) progenitors exhibit continued proliferation and delayed differentiation, which are modulated by FGF4/8/10, BMP and canonical Wnt/β-catenin signaling. PTEN-Akt signaling regulates the stem cell/progenitor cell homeostasis in several systems, such as hematopoietic stem cells, intestinal stem cells and neural progenitor cells. To address whether PTEN-Akt signaling is involved in regulating cardiac progenitors, we deleted Pten in SHF progenitors. Deletion of Pten caused SHF expansion and increased the size of the SHF derivatives, the right ventricle and the outflow tract. Cell proliferation of cardiac progenitors was enhanced, whereas cardiac differentiation was unaffected by Pten deletion. Removal of Akt1 rescued the phenotype and early lethality of Pten deletion mice, suggesting that Akt1 was the key downstream target that was negatively regulated by PTEN in cardiac progenitors. Furthermore, we found that inhibition of FOXO by Akt1 suppressed the expression of the gene encoding the BMP ligand (BMP7), leading to dampened BMP signaling in the hearts of Pten deletion mice. Cardiac activation of Akt also increased the Ser552 phosphorylation of β-catenin, thus enhancing its activity. Reducing β-catenin levels could partially rescue heart defects of Pten deletion mice. We conclude that Akt signaling regulates the cell proliferation of SHF progenitors through coordination of BMP signaling and β-catenin activity.
Monolayer cells are largely different from tumor masses, and might misguide drug screenings. 3D in vitro cell culture models simulate the characteristics of tumor masses in vivo and have recently been used in many studies of anti-cancer drugs. Among various 3D cell culture models, multi-cellular layer (MCL) models allow for the direct quantitative assessment of the penetration of chemotherapeutic agents through solid tissue environments without requiring the use of fluorescently labeled drugs or imaging molecules. Therefore, in our present study, a 3D-no base and embedded MCF-7 MCL model was successfully developed for a 14-day culture. Over time, its thickness and cell layers increased and exhibited highly proliferative properties and drug resistance to adriamycin (ADR) with markedly elevated IC50 values. Meanwhile, G2/M stage cycle arrest was also observed, which likely up-regulated P-gp expression through the Chk2/p53/NF-κB pathway. The elevated P-gp expression altered the ADR penetration kinetics in MCF-7 MCLs in vitro by accelerating the apparent penetration of ADR through the intercellular spaces of the MCLs. Additionally, a decreased ADR retention within tumor cells was observed, but could be significantly reversed by a P-gp inhibitor. The attenuated ADR retention in the deeper cells of tumor masses was confirmed in xenografted mice in vivo. This phenomenon could be elucidated by the mathematical modeling of penetration kinetics parameters. Our study provided a new model that evaluated and improved the quantification of the drug penetration kinetics, revealed the relationship between P-gp and drug penetration through tumor masses, and suggested the potential molecular mechanisms.
Gastrokine‑2 is a putative gastric cancer‑specific tumor suppressor gene, the loss of which is known to be involved in the development and progression of gastric cancer, and restoration of gastrokine‑2 expression inhibits growth of gastric cancer cells in vitro. However, the underlying mechanism of these effects requires elucidation. In the present study, expression patterns of gastrokine‑2 protein were examined in gastric cancer tissues and cell lines. Expression of gastrokine‑2 was restored in gastric cancer cells in order to assess its effect on cell viability, apoptosis and gene expression. A total of 76 gastric cancer tissues with corresponding normal mucosae samples, and two gastric cancer cell lines (SGC‑7901 and AGS) were subjected to western blot analysis of gastrokine‑2 expression. SGC‑7901 cells were transiently transfected with gastrokine‑2 cDNA and then treated with anti‑CD95 and/or anti‑Fas antibodies prior to analysis of cell viability, apoptosis and gene expression levels. Expression of gastrokine‑2 protein was reduced or absent in gastric cancer tissues and gastric cancer cell lines. Following restoration of gastrokine‑2 expression, the protein expression level of Fas was significantly increased, but no marked change was observed in the levels of bcl‑2 and Bax proteins. Expression of gastrokine‑2 protein reduced gastric cancer cell viability and induced apoptosis. Activity of caspase‑3 and caspase‑8 was increased, but caspase‑9 activity remained unchanged in the SGC‑7901 cells. Reduction or knockout of gastrokine‑2 protein expression may contribute to gastric cancer development or progression, as the current study demonstrated that restoration of gastrokine‑2 expression induces apoptosis of gastric cancer cells through the extrinsic apoptosis pathway.
In the current study, for the first time, we found that metastasis-associated gene 1 (MTA1) was a higher-order chromatin structure organizer that decondenses the interphase chromatin and mitotic chromosomes. MTA1 interacts dynamically with nucleosomes during the cell cycle progression, prominently contributing to the mitotic chromatin/chromosome structure transitions at both prophase and telophase. We showed that the decondensation of interphase chromatin by MTA1 was independent of Mi-2 chromatin remodeling activity. H1 was reported to stabilize the compact higher-order chromatin structure through its interaction with DNA. Our data showed that MTA1 caused a reduced H1-chromatin interaction in-vivo. Moreover, the dynamic MTA1-chromatin interaction in the cell cycle contributed to the periodical H1-chromatin interaction, which in turn modulated chromatin/chromosome transitions. Although MTA1 drove a global decondensation of chromatin structure, it changed the expression of only a small proportion of genes. After MTA1 overexpression, the up-regulated genes were distributed in clusters along with down-regulated genes on chromosomes at parallel frequencies.
Adipose and endothelial dysfunction is tightly associated with cardiovascular diseases in obesity and insulin resistance. Because perivascular adipose tissue (PVAT) surrounds vessels directly and influences vessel functions through paracrine effect, and AMP-activated protein kinase (AMPK) and sirtuin 1 (SIRT1) show similarities in modulation of metabolic pathway, we hypothesized that activation of AMPK and SIRT1 in PVAT might regulate the endothelial function in pathological settings. Thus, in this study, we focused on the regulation of AMPK and SIRT1 activities implicated in adipocytokine expression and endothelial homeostasis under inflammatory conditions by using salicylate, metformin, AICA riboside (AICAR) and resveratrol as AMPK activating agents. We prepared conditioned medium (CM) by stimulating PVAT with palmitic acid (PA) and observed the effects of AMPK activating agents on adipocytokine expression and vessel vasodilation in rats. Moreover, we explored the effects of resveratrol and metformin in fructose-fed rats. We observed that PA stimulation induced inflammation and dysregulation of adipocytokine expression accompanied with reduced AMPK activity and SIRT1 abundance in PVAT. AMPK activating agents inhibited NF-κB p65 phosphorylation and suppressed gene expression of pro-inflammatory adipocytokines, and upregulated adiponectin and PPARγ expression in PVAT in an AMPK/SIRT1-interdependent manner. Meanwhile, CM stimulation impaired endothelium-dependent vasodilation in response to acetylcholine (ACh). Pretreatment of CM with AMPK-activating agents enhanced eNOS phosphorylation in the aorta and restored the loss of endothelium-dependent vasodilation, whereas this action was abolished by co-treatment with AMPK inhibitor compound C or SIRT1 inhibitor nicotinamide. Long-term fructose-feeding in rats induced dysregulation of adipocytokine expression in PVAT and the loss of endothelium-dependent vasodilation, whereas these alterations were reversed by oral administration of resveratrol and metformin. Altogether, pharmacological activation of AMPK beneficially regulated adipocytokine expression in PVAT and thus ameliorated endothelial dysfunction against inflammatory insult in an AMPK/SIRT1-interdependent manner.
In the previous study, we demonstrated that fluoxetine (FLX) regulated lipogenic and lipolytic genes to promote hepatic lipid accumulation. On this basis, underlying mechanisms were investigated by focusing on the intracellular signaling transduction in the present study using primary mouse hepatocytes. The expression of lipogenesis- and lipolysis-related genes was evaluated with the application of specific activators and inhibitors. Activation status of respective signaling pathway and the lipid accumulation in hepatocytes were analyzed. We provided evidence that AMP-activated protein kinase (AMPK) activator AICAR (5-aminoimidazole-4-carboxamide-1-β-D-ribofuranoside) significantly suppressed the increased expression of representative lipogenesis-related genes, acetyl-CoA carboxylase (ACC) and fatty acid synthase (FAS) by FLX, while increased the repressed expression of lipolysis-related genes, carboxylesterases. In the meanwhile, FLX regulated the above genes in the same way as AMPK inhibitor Compound C did. Furthermore, AICAR inhibited the proteolytic activation of SREBP1c induced by FLX, resulting in the decreased level of nuclear SREBP1c. Further studies demonstrated that FLX significantly suppressed the phosphorylation of AMPK and subsequent phosphorylation of ACC, following the inhibited phosphorylation and nuclear export of liver kinase B1 (LKB1). As a functional analysis, FLX-induced lipid accumulation in hepatocytes was repeatedly abolished by AICAR. In conclusion, FLX-induced hepatic lipid accumulation is mediated by the suppression of AMPK signaling pathway. The findings not only provide new insight into the understanding of the mechanisms for selective serotonin reuptake inhibitors-mediated dyslipidemia effects, but also suggest a novel therapeutic target to interfere.
Colorectal cancer (CRC) is one of the most common causes of cancer-related death worldwide. The leucine-rich repeat-containing G protein-coupled receptor 5 (LGR5) is a newly identified surface marker of colorectal cancer stem cells (CSCs). Expression level of LGR5 is commonly elevated in human CRCs. Our previous study demonstrated that the elevated expression of LGR5 is associated with CRC initiation and progression. However, the role of LGR5 in CRC pathogenesis has not been sufficiently established. In this study, we aimed to characterize the role of LGR5 in CRC pathogenesis using the loss-of-function approach. Depletion of LGR5 suppressed the growth of several cultured CRC cells and caused an increase in the fraction of apoptotic cells, which were analyzed using Annexin V/PI staining and DNA fragmentation assay. Furthermore, depleting LGR5 induced apoptosis through the loss of mitochondrial membrane potential. Additionally, depletion of LGR5 suppressed β-catenin nuclear translocation and blocked the activity of Wnt/β-catenin signaling as manifested in the reduced expression of c-myc and cyclin D, two Wnt/β-catenin targets in CRC cells. Treatment with Wnt3a considerably alleviated the growth inhibition and apoptotic cell death induced by LGR5 depletion in CRC cells. These data suggested that LGR5 regulates cell proliferation and survival by targeting the Wnt/β-catenin signaling pathway. Thus, the findings of this study suggest that LGR5 plays a vital role in CRC pathogenesis and has the potential to serve as a diagnostic marker and a therapeutic target for CRC patients.
The functions and mechanisms of metastasis-associated protein 1 (MTA1) in cancer progression are still unclear due to a lagged recognition of the subcellular localization. In the present study, using multiple molecular technologies we confirmed for the first time that MTA1 localizes to the nucleus, cytoplasm and nuclear envelope. MTA1 is primarily localized in the nucleus of normal adult tissues but in the cytoplasm of embryonic tissues. While in colon cancer, both distributions have been described. Further investigation revealed that MTA1 localizes on the nuclear envelope in a translocated promoter region (TPR)-dependent manner, while in the cytoplasm, MTA1 shows an obvious localization on microtubules. Both nuclear and cytoplasmic MTA1 are associated with cancer progression. However, these functions may be associated with different mechanisms because only nuclear MTA1 has been associated with cancer differentiation. Overexpression of MTA1 in HCT116 cells inhibited differentiation and promoted proliferation, whereas MTA1 knockdown resulted in cell differentiation and death. Theses results not only suggest that nuclear MTA1 is a good marker for cancer differentiation diagnosis and a potential target for the treatment of cancers but also reveal the necessity to differentially examine the functions of nuclear and cytoplasmic MTA1.
VISA (also known as MAVS, Cardif, IPS-1) is the essential adaptor protein for virus-induced activation of IFN regulatory factors 3 and 7 and production of type I IFNs. Understanding the regulatory mechanisms for VISA will provide detailed insights into the positive or negative regulation of innate immune responses. In this study, we identified Smad ubiquitin regulatory factor (Smurf) 2, one of the Smad ubiquitin regulator factor proteins, as an important negative regulator of virus-triggered type I IFN signaling, which targets at the VISA level. Overexpression of Smurf2 inhibits virus-induced IFN-β and IFN-stimulated response element activation. The E3 ligase defective mutant Smurf2/C716A loses the ability to suppress virus-induced type I IFN signaling, suggesting that the negative regulation is dependent on the ubiquitin E3 ligase activity of Smurf2. Further studies demonstrated that Smurf2 interacted with VISA and targeted VISA for K48-linked ubiquitination, which promoted the degradation of VISA. Consistently, knockout or knockdown of Smurf2 expression therefore promoted antiviral signaling, which was correlated with the increase in protein stability of VISA. Our findings suggest that Smurf2 is an important nonredundant negative regulator of virus-triggered type I IFN signaling by targeting VISA for K48-linked ubiquitination and degradation.
Bursopentine (BP5), a novel pentapeptide isolated from chicken bursa of fabricius, has been proved to have immunomodulatory effects on B and T lymphocytes, anti-oxidative stress on macrophages, and antiproliferation on tumor cells. However, the effects of BP5 on the immune function exhibited by dendritic cells (DCs), which are regarded as a major target for immunomodulators, remain unknown. In this study, we examined the effects of BP5 on the activation and maturation of murine bone marrow-derived DCs. Our results showed that BP5 significantly suppressed the secretion of lipopolysaccharide (LPS)-induced pro-inflammatory (TNF-α, IL-1β, IL-6 and IL-12p70) and anti-inflammatory (IL-10) cytokines by DCs, and this impact was not due to its cytotoxicity. Besides, BP5 reversed the morphological changes and attenuated the expression of phenotypic markers (MHC II, CD40, CD80 and CD86 molecules) in LPS-induced DCs. Furthermore, BP5 restored the decreased FITC-dextran uptake in LPS-treated DCs, arrested the LPS-induced migration of DCs and abrogated the promoting ability of LPS-induced DCs for allogeneic T cell proliferation. These findings show a new immunopharmacological capability of BP5 and provide a novel approach in the prevention and therapy of chronic inflammation and autoimmunity via abolishing the immune function of DCs.
While cancer cell mitochondria mediate actions of many successful chemotherapeutics, little is known about mitochondrial response in mTOR-targeted anticancer therapy. We have studied mitochondrial dynamics in relation to growth suppression employing an allosteric inhibitor rapalog, a highly selective mTOR kinase inhibitor (mTOR-KI) and mTOR-ShRNA. Global targeting of mTOR increased mitochondrial membrane potential (mΔψ) and inhibited mitochondrial permeability transition pore (mPTP). Importantly, these mTOR-KI-provoked anti-survival and pro-survival effects were differentially manifested in diverse cancer cells according to intrinsic susceptibility to mTOR-targeting. The most-sensitive cells including those possessing hyperactive PI3K/AKT/mTOR and/or growth factor-dependence (LNCap, MDA361 and MG63) all displayed a dramatic increase in mΔψ, whereas the mΔψ increase was not evident in majority of resistant cancer cells. Upon mTOR-KI treatment, the resistant cells including those harboring K-Ras- or B-Raf mutation (MDA231, HT29 and HCT116) all displayed a markedly reduced mPTP opening, which paralleled a sustained AKT-hexokinase 2 (HK2) survival signaling and persistent phosphorylation (inactivation) of GSK3β. Further studies demonstrated that the mTOR-KI-provoked mPTP closure in resistant cells was mediated through an enhanced binding of HK2 to the mitochondrial voltage-dependent anion channel (VDAC), a molecular mechanism known to promote mPTP closure and cell survival. Detaching HK2 from VDAC by an HK2-displacing peptide or methyl jasmonate specifically blocked the mTOR-KI-provoked mPTP closure and potentiated growth suppression in resistant cells. Thus, mTOR-inhibition can exert complex and differential perturbation to mitochondrial dynamics in cancer cells, which likely influence therapeutic outcome of mTOR-targeted therapy.
Tumor necrosis factor (TNF)-α is a potent cytokine that regulates critical cellular processes including apoptosis. TNF-α usually triggers both survival and apoptotic signals in various cell types. Heat shock protein 27 (HSP27), an important cellular chaperone, is believed to protect cells from apoptosis. HSP27 can be phosphorylated and changed its cellular function according to different stimuli. However, available reports on the role of HSP27 phosphorylation in apoptosis remain elusive. In this study, we investigated the role of HSP27 phosphorylation in TNF-α induced apoptosis in human cervical carcinoma (HeLa) cells. We found that TNF-α induced apoptosis was enhanced if we suppressed the TNF-α induced HSP27 phosphorylation by specific inhibitor CMPD1 or MAPKAPK2 (MK2) knockdown or by overexpression of non-phosphorylatable mutant HSP27-3A. Through co-immunoprecipitation and confocal microscopy, we observed that HSP27 associated with transforming growth factor-β (TGF-β)-activated kinase 1 (TAK1) in response to TNF-α stimulation. By blocking MK2 activity or overexpressing phospho-mimetic mutant Hsp27-3D, we further showed that HSP27 phosphorylation facilitated the TNF-α induced ubiquitination and phosphorylation of TAK1 and the activations of p38 MAPK and ERK, the TAK1 downstream pro-survival signaling. In addition, we also found that increased HSP27 phosphorylation inhibited TRADD ubiquitination but did not influence the binding between TRADD and FADD in a pro-apoptotic complex. Taken together, our data indicated that HSP27 phosphorylation was involved in modulating the TNF-α induced apoptosis via interacting with TAK1 and regulating TAK1 post-translational modifications in HeLa cells. This study demonstrates that HSP27 phosphorylation serves as a novel regulator in TNF-α-induced apoptosis, and provides a new insight into the cytoprotective role of HSP27 phosphorylation.
The Seipin gene was originally found to be responsible for type 2 congenital lipodystrophy and involved in lipid droplet formation. Seipin is highly expressed in the central nervous system as well. Seipin mutations have been identified in motor neuron diseases such as Silver syndrome and spastic paraplegia. In this study, we generated neuron-specific seipin knockout mice (seipin-nKO) to investigate the influence of seipin deficiency on locomotion and affective behaviors. In comparison with control mice, 8-week-old male seipin-nKO mice, but not female mice, displayed anxiety- and depression-like behaviors as assessed by open-field, elevated plus-maze, forced swim and tail suspension tests. However, neither male nor female seipin-nKO mice showed locomotion deficits in swimming tank and rotarod tests. Interestingly, the mRNA and protein levels of peroxisome proliferator-activated receptor gamma (PPARγ) in the hippocampus and cortex were lower in male seipin-nKO mice, but not female mice, than controls. In seipin-nKO mice, plasma levels of sex hormones including 17β-estradiol (E2) in females and testosterone in males as well as corticosterone were not altered compared with controls. The treatment of male seipin-nKO mice with E2 ameliorated the anxiety- and depression-like behaviors and remarkably increased PPARγ levels. The PPARγ agonist rosiglitazone alleviated affective disorders in male seipin-nKO mice. Notably, anxiety- and depression-like behaviors appeared in female seipin-nKO mice after ovariectomy, which was associated with low PPARγ expression. Collectively, these results indicate that neuronal seipin deficiency causing reduced PPARγ levels leads to affective disorders in male mice that are rescued by E2-increased PPARγ expression.
Chronic cerebral hypoperfusion is thought to induce white matter lesions (WMLs), which contribute to cognitive impairment. Although inflammation and oligodendrocyte apoptosis are believed to be involved in the pathogenesis of WMLs, effective therapies have not been identified yet. This study investigated whether catalpol, an iridoid glycoside, can alleviate WMLs by promoting oligodendrocyte survival and oligodendrocyte progenitor differentiation via the Akt signaling pathway in rats with chronic cerebral hypoperfusion. A rat model of chronic cerebral hypoperfusion was created through permanent occlusion of bilateral common carotid arteries. Catalpol (5mg/kg) or saline was intraperitoneally administered daily for 10 days following the operation. On the 30th day after surgery, inflammation, oligodendrocyte apoptosis, and myelin damage in the ischemic white matter were more severe and evident than in the sham control group. Treatment with catalpol significantly suppressed white matter inflammation and attenuated oligodendrocyte apoptosis and myelin damage. The expression of phosphorylated Akt (p-Akt) and the number of mature oligodendrocytes were also markedly increased by catalpol treatment, and these effects were reversed by the PI3K inhibitor LY294002. In conclusion, catalpol attenuates hypoperfusion-induced WMLs by promoting oligodendrocyte survival and oligodendrocyte progenitor differentiation through the Akt signaling pathway. Our results suggest that catalpol may be a candidate for treating cerebrovascular WMLs.
Asiaticoside (AS) is isolated from Centella asiatica (L.) which has been using for a long time as a memory enhancing drug in India. This study was to investigate the effects of AS on memory impairment and inflammatory cytokines expression induced by transient cerebral ischemia and reperfusion in mice, as well as the potential signaling pathway. Transient bilateral common carotid artery occlusion (tBCCAO) induced severe memory deficits in mice according to the Morris water maze task and the step-down passive avoidance test. Meanwhile the microglial activation and the gene expression of inflammatory cytokines including interleukin (IL)-1β, interleukin (IL)-6 and tumor necrosis factor (TNF)-α were increased in the hippocampus of the mice with cerebral ischemia and reperfusion. Oral administration of AS (40 and 60 mg/kg, once per day, started the day after surgery and lasted for 7 days) significantly ameliorated the memory impairment and the inflammation. Moreover, AS (20, 40 and 60 mg/kg) markedly reduced the microglial overactivation and the phosphorylation of p38 MAPK in hippocampus compared with the transient cerebral ischemia and reperfusion group. These results suggested that AS showed the neuroprotective effect against transient cerebral ischemia and reperfusion in mice, and this effect might be associated with the anti-inflammation effect of AS via inhibiting overactivation of p38 MAPK pathway.
Secondary brain injury following subarachnoid hemorrhage (SAH) is poorly understood. We utilized a rat model of SAH to investigate whether SIRT1 has a protective role against brain edema via the tumor suppressor protein p53 pathway. Experimental SAH was induced in adult male Sprague-Dawley rats by prechiasmatic cistern injection. Brain SIRT1 protein levels were examined in the sham controls and in rats 6, 12, 24, 48, and 72 hr after SAH induction. The SIRT1 inhibitor sirtinol was administered by intracerebroventricular infusion. Neurological functions, blood-brain barrier (BBB) disruption, and brain water content were assessed. Endothelial cell apoptosis, caspase 3 protein expression, p53 acetylation, and matrix metalloproteinase-9 (MMP-9) activity were examined. Compared with the control, SIRT1 protein expression increased remarkably, reaching a maximum at 24 hr after SAH. Sirtinol treatment significantly lowered SIRT1 expression, accompanied by deteriorated neurologic function, BBB disruption, brain edema, increased endothelial cell apoptosis, and increased MMP-9 gelatinase activity compared with the rats treated with vehicle only. Our results suggest that increased expression of endogenous SIRT1 may play a neuroprotective role against brain edema after SAH.
The epidermal growth factor receptor (EGFR) is an important receptor tyrosine kinase member in animals, which plays versatile functions in development, growth, tissue regeneration etc. Current knowledge on EGFR is poor in bivalve mollusks. In this study, we cloned and analyzed an EGFR gene from the Pacific oyster Crassostrea gigas (cgegfr). A 5,731 bp full-length cDNA of cgegfr was obtained, encoding a peptide with 1,494 amino acids which exhibited a typical EGFR structure, including an extracellular region, a single transmembrane region and an intracellular region. A conserved tyrosine kinase domain was predicted in the intracellular region, while the extracellular region responsible for ligand binding showed comparatively poor conservation. Expression analysis revealed that cgefgr was expressed widely in C. gigas tissues and a highest expression level was observed in adductor tissue. Expression of cgegfr was revealed to be up-regulated during wound healing of mantle, indicating that EGFR might function in the cell proliferation and migration during wound healing. Further functional analysis of cgegfr was conducted in mouse myoblast cell line C2C12, in which different parts of cgegfr were expressed and their effects were measured. The results revealed that cgegfr was able to accelerate cell proliferation of C2C12 cells and the transmembrane region was necessary for self-activation of truncated cgegfr. Our results would provide supports for further studies on the roles of cgegfr in development and growth in C. gigas.
Obesity is a worldwide epidemic, and a risk factor for cardiovascular disease and type 2 diabetes. Consequently, the development of safe and effective anti-obesity drugs is an area of ongoing clinical interest. MicroRNAs play a vital role in anti-obesity by inhibiting the expression of genes involved in adipogenesis and lipogenesis. However, the clinical application of miRNAs has been limited by a lack of appropriate delivery systems. The discovery of microvesicles (MVs) has shed new light on the search for more efficient drug transport tools. In a previous study, we demonstrated that miRNA-130b suppressed fat deposition by inhibiting PPAR-g expression. In order to demonstrate whether miRNA-130b can be packaged into MVs and function as an endogenous form of miRNA-130b in recipient cells, we transfected HeLa-229 cells with plasmid to overexpress miRNA-130b. This enabled HeLa-229 cells to selectively package miRNA-130b into MVs and actively secrete the miRNA-130b enriched MVs into the culture media. We further verified that MVs enriched with miRNA-130b contain elevated concentrations of Argonaute 2 and heat shock protein 90a which are known to protect the circulating miRNAs from degradation. Exposure of primary cultured porcine adipocytes to purified, miRNA-130b-enriched MVs resulted in a significant down-regulation of PPAR-g expression which was associated with reduced adipogenesis and lipogenesis. Taken together, our results suggest that MVs may provide an effective transport systems for the deliver of miRNAs for therapeutic use. We also showed that MV-shuttled miRNA-130b inhibited adipogenesis and lipogenesis, and reduced fat deposition in recipient adipocytes by targeting PPAR-g.
Extracellular polysaccharides (EPSs) are high-molecular weight sugar-based polymers that are synthesized and secreted by many microorganisms. Recently, EPSs have attracted particular attention due to their multiple biological functions including anti-inflammation. However, studies rarely reported the molecular mechanisms underlying their functions. We previously purified an EPS from an oligotrophic bacteria (Bacillus sp. LBP32) found in Lop Nur Desert, which possesses a potent antioxidant activity, while the anti-inflammatory effects of EPS and signaling mechanisms underlying its action have not been clarified. In this study, we demonstrated that EPS significantly inhibited the LPS-induced release of pro-inflammatory mediators, such as nitric oxide (NO), IL-6 and TNF-α, without any significant cytotoxicity. EPS also downregulated the expression of nitric oxide synthase (iNOS) induced by LPS. Furthermore, activation of nuclear factor κB (NF-κB) was abrogated by EPS through inhibited the phosphorylation of IκB kinase (IKK). Activations of Mitogen-activated protein kinases (MAPKs), including p38 MAPK and c-Jun N-terminal kinase (JNK), were also found to be inhibited by EPS. In addition, the level of intracellular reactive oxygen species (ROS) was also significantly decreased with the treatment of EPS. In vivo experiments were conducted and showed that EPS could greatly improve the outcome of mice with LPS-induced endotoxic shock. Taken together, our data indicate that EPS prevents LPS-induced inflammatory response by inhibiting NF-κB and MAPKs activation and ROS production.
Multifunctional silica nano-vehicles (SiO2@indol-IL) and magnetic nanoparticles (Fe3O4@indol-IL) were constructed through the Schiff bases condensation of indole-3-carboxaldehyde and 4-acetyl-N-allyl pyridinium chloride (ILs) with the amine groups of silica and magnetic nanoparticles. SiO2@indol-IL can inhibit the proliferation of HepG-2 cells in 48 h. Fe3O4@indol-IL can mimic the function of catalase to disproportionate H2O2 to O2, and has obvious effect on the proliferation of HepG-2 cells in 72 h. Moreover, the two nanoparticles show some inhibition on the expression of hypoxia inducible factor (HIF-1α), glucose transporter (GLUT1) and the production of lactate in HepG-2 cells. Therefore, we deduced that indole conjugated silica and magnetic nanparticles could be used as inhibitors of HIF-1α or GLUT1.
Astrocytes, the most common cell type in the brain, play a principal role in the repair of damaged brain tissues during external radiotherapy of brain tumours. As a downstream gene of p53, the effects of Krüppel-like factor 4 (KLF4) in response to X-ray-induced DNA damage in astrocytes are unclear. In the present study, KLF4 expression was upregulated after the exposure of astrocytes isolated from the murine brain. Inhibition of KLF4 expression using lentiviral transduction produced less double-strand DNA breaks (DSB) determined by a neutral comet assay and flow cytometric analysis of phosphorylated histone family 2A variant and more single-strand DNA breaks (SSB) determined by a basic comet assay when the astrocytes were exposed to 4 Gy of X-ray radiation. These data suggest that radiation exposure of the tissues around brain tumour during radiation therapy causes KLF4 overexpression in astrocytes, which induces more DSB and reduces SSB. This causes the adverse effects of radiation therapy in the treatment of brain tumours.
Rac-1, which is a member of the Rho guanosine triphosphatase (GTPase) family, has been demonstrated to play an important role in cancer invasion and metastasis. In this study, we investigated the clinical and prognostic significance of Rac-1 in esophageal squamous cell carcinoma (ESCC). The protein and messenger ribonucleic acid (mRNA) levels of Rac-1 in normal esophageal epithelia cells and paired ESCC tissues were examined by Western blot and reverse transcription polymerase chain reaction. The results showed that Rac-1 was upregulated at the protein and mRNA levels in ESCC cancerous specimens compared with normal esophageal tissues. We then examined the correlation between Rac-1 expression and clinicopathological features using immunochemical analysis of 233 surgically resected ESCC. Rac-1 protein was expressed in 228 (97.85%) cancer tissues with cytoplasm staining, and there were significant correlations between Rac-1 expression and tumor location (P = 0.045), tumor stage (P = 0.020), tumor depth (P = 0.023) and lymph node metastasis (P = 0.009). The overall survival and disease-free rates of ESCC patients with high Rac-1 expression were much lower than those with low Rac-1 expression (P < 0.001; P < 0.001, respectively). Multivariate analysis showed that high Rac-1 expression and lymph node metastasis were two independent factors for poor survival (P < 0.001; P < 0.001, respectively). The results in this study indicate, for the first time, that Rac-1 is involved in the invasion and metastatic progression of ESCC and may be a potential marker for evaluating the prognosis of ESCC patients and a therapy target for ESCC.
The neuroblastoma breakpoint family (NBPF) has been reported to play potential roles in the development of neuroblastoma and human evolution. However, the exact regulation and function of this family is still unknown. In this study, the genes of NBPF family were found to be densely covered by many high-confidence ChIP-Seq peaks of NF-κB. The expressions of NBPF genes were thus deduced to be regulated by this transcription factor. The activities of NF-κB in HeLa, HepG2 and ECa109 cells were then manipulated with NF-κB activator (TNFα) and inhibitors (BAY11-7082 or p65 siRNA), and the expressions of NBPF genes in these cells were checked. As result, it was found that the expressions of NBPF genes were regulated by NF-κB in HeLa and HepG2 cells. Therefore, the genes of NBPF family were identified as new bona fide direct target genes of NF-κB. In addition, NBPF was also identified as a nuclear protein by in silico prediction and immunolocalization. Finally, the bioinformatics analysis revealed that most of NBPF proteins contained classical nuclear localization signals (NLSs) and a conserved DNA-binding domain similar to the transcription factor stat3b/dna complex or stat-1/dna complex in their N-terminals. Therefore, this study concluded that NBPF was nuclear protein that contained classical NLSs and conserved known DNA-binding domain, and its expression was regulated by another important transcription factor, NF-κB. These findings suggest that NBPF may function as DNA-binding transcription factor in nucleus, which provides important new insight into the functions of NBPF genes in the human cells.
Liver cancer stem cells (LCSCs) can drive and maintain hepatocellular carcinoma (HCC) growth, metastasis, and recurrence. Therefore, they are potentially responsible for the poor prognosis of HCC. Oxygen and nutrient deficiencies are common characteristics of the tumor microenvironment. However, how LCSCs adapt to oxygen- and nutrient-deprived conditions is unclear. Here, we used immunofluorescent staining and flow cytometry analysis to show that CD133+ cells were significantly enriched after hypoxia and nutrient starvation (H/S) in the human HCC cell line Huh7. Sorted CD133+ cells showed higher survival, less apoptosis, and possess higher clonogenic ability under H/S compared to the CD133- population. Under H/S, electron microscopy revealed more advanced autophagic vesicles in CD133+ cells. Additionally, CD133+ cells had higher autophagy levels as measured by both RT-qPCR and Western blotting. CD133+ cells had more accumulated GFP-LC3 puncta, which can be detected by fluorescence microscopy. The autophagic inhibitor chloroquine (CQ) significantly increased apoptosis and decreased the clonogenic capacity of CD133+ cells under H/S. Pre-culturing in H/S enhanced the sphere-forming capacity of CD133+ cells. However, CQ significantly impaired this process. Therefore, autophagy is essential for LCSCs maintenance. CD133+ cells were also found to have a higher tumor-forming ability in vivo, which could be inhibited by CQ administration. Collectively, our results indicate that the involvement of autophagy in maintenance of CD133+ LCSCs under the oxygen- and nutrient-deprived conditions that are typical of the tumor microenvironment in HCC. Therefore, autophagy inhibitors may make LCSCs more sensitive to the tumor microenvironment and be useful in improving anti-cancer treatments.
Recently, we have indicated that microcystin-LR, a cyanobacterial toxin produced in eutrophic lakes or reservoirs, can increase invasive ability of melanoma MDA-MB-435 cells; however, the stimulatory effect needs identification by in vivo experiment and the related molecular mechanism is poorly understood. In this study, in vitro and in vivo experiments were conducted to investigate the effect of microcystin-LR on invasion and metastasis of human melanoma cells, and the underlying molecular mechanism was also explored. MDA-MB-435 xenograft model assay showed that oral administration of nude mice with microcystin-LR at 0.001-0.1 mg/kg/d posed no significant effect on tumor weight. Histological examination demonstrated that microcystin-LR could promote lung metastasis, which is confirmed by Matrigel chamber assay suggesting that microcystin-LR treatment at 25 nM can increase the invasiveness of MDA-MB-435 cells. In vitro and in vivo experiments consistently showed that microcystin-LR exposure increased mRNA and protein levels of matrix metalloproteinases (MMP-2/-9) by activating phosphatidylinositol 3-kinase (PI3-K)/AKT. Additionally, microcystin-LR treatment at low doses (≤25 nM) decreased lipid phosphatase PTEN expression, and the microcystin-induced invasiveness enhancement and MMP-2/-9 overexpression were reversed by the PI3-K/AKT chemical inhibitor LY294002 and AKT siRNA, indicating that microcystin-LR promotes invasion and metastasis of MDA-MB-435 cells via the PI3-K/AKT pathway.
The increase of eukaryotic translation initiation factor 4E (eIF4E) expression is frequently observed in several types of cancer, making eIF4E an attractive anticancer drug target. However, the role of eIF4E in gastric cancer pathogenesis remains unclear. Perifosine is a bioavailable alkylphospholipid exhibiting antitumor activity in a series of cancer types. In this study, gastric cancer cell lines were selected to explore the role of eIF4E as a potential target for treating human gastric cancer. The expression of total eIF4E (T-eIF4E)and phosphorylated eIF4E (p-eIF4E) in gastric cancer samples was detected by immunohistochemical assay. RNA interference was used to silence eIF4E expression. Sulforhodamine B assay was performed to evaluate tumor cell viability. Colony formation assay was used to examine the effects of eIF4E small interfering RNA (siRNA) or perifosine on colony formation. The mRNA levels of eIF4E were analyzed by qRT-PCR and western blot analysis was carried out to evaluate the expression of Akt and eIF4E. The results showed that increased expression levels of T-eIF4E and p-eIF4E were found in gastric cancer tissues and cells. Reduced eIF4E expression blocked the proliferation of gastric cancer cells. Perifosine downregulated the T-eIF4E and p-eIF4E levels in a dose- and time-dependent manner; it also inhibited the growth of gastric cancer cells. Moreover, this inhibitory effect was significantly enhanced by the combination of eIF4E siRNA and perifosine treatments. Our results indicate that eIF4E gene silencing can inhibit tumor cell growth, and eIF4E can be developed as a promising therapeutic target for gastric cancer.
Recently, many nutraceutical products containing the powdered or extracted parts of C. militaris have become available for health care. Due to the increased morbidity and mortality, poisonings associated with the use of herbs have raised the universal attention. Herein, we carried out the 28-day repeated toxicity test in male and female ablactated rats (three weeks old) given C. militaris powder orally at 0 (control), 1, 2, and 3 g/kg per day. Noticeable increments of serum aspartate and alanine aminotransferase (ALT and AST) levels were observed for both sexes, suggestive of weak hepatic toxicity. Nephrotoxicity characterized by tubular epithelium degeneration and necrosis was observed at the high dose, and the male rats were more susceptible to renal toxicity than female rats. In addition, the genes and protein expressions of novel markers of kidney toxicity, such as kidney injury molecule-1 (KIM-1) were enlarged in the renal cortex and the urine. Moreover, C. militaris treatment significantly decreased superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) activities. However, the ratio of glutathione oxidized form (GSSG)/glutathione reduced form (GSH) was increased by C. militaris treatment. We conclude that dietary contamination with C. militaris may have renal toxicity potentials, at least in part by causing oxidative damage to the kidney.
Cardiac hypertrophy is the heart's response to hypertrophic stimuli and is associated with increased mortality. Vinexin-β is a vinculin-binding protein that belongs to a family of adaptor proteins and mediates signal transduction and actin cytoskeleton organisation. A previous study has shown that Vinexin-β is ubiquitously expressed and that it is highly expressed in the heart. However, a critical role for Vinexin-β in cardiac hypertrophy has not been investigated. Therefore, to examine the role of Vinexin-β in pathological cardiac hypertrophy, we used Vinexin-β knockout mice and transgenic mice that overexpress human Vinexin-β in the heart. Cardiac hypertrophy was induced by aortic banding (AB). The extent of cardiac hypertrophy was quantitated by echocardiography and pathological and molecular analyses of heart samples. Our results demonstrated that Vinexin-β overexpression in the heart markedly attenuated cardiac hypertrophy, fibrosis, and cardiac dysfunction, whereas loss of Vinexin-β exaggerated the pathological cardiac remodelling and fibrosis response to pressure overload. Further analysis of the in vitro and in vivo signalling events indicated that beneficial Vinexin-β effects were associated with AKT signalling abrogation. Our findings demonstrate for the first time that Vinexin-β is a novel mediator that protects against cardiac hypertrophy by blocking the AKT signalling pathway.
The tumor suppressor p53 is essential for several cellular processes that are involved in the response to diverse genotoxic stress, including cell cycle arrest, DNA repair, apoptosis and senescence. Studies of the regulation of p53 have mostly focused on its stability and transactivation; however, new regulatory molecules for p53 have also been frequently identified. Here, we report that human ssDNA binding protein SSB1 (hSSB1), a novel DNA damage-associated protein, can interact with p53 and protect p53 from ubiquitin-mediated degradation. Furthermore, hSSB1 also associates with the acetyltransferase p300 and is required for efficient transcriptional activation of the p53 target gene p21 by affecting the acetylation of p53 at lysine382. Functionally, the hSSB1 knockdown-induced abrogation of the G2/M checkpoint is partially dependent on p53 or p300. Collectively, our results indicate that hSSB1 may regulate DNA damage checkpoints by positively modulating p53 and its downstream target p21.
Multiple sclerosis (MS) is an irreversible and demyelinating disease of the central nervous system, in part influenced by chronic inflammation. There is no proven effective therapy to stop the pathological progression of MS, although suppressing the immune system to control the inflammatory response may improve the clinical performance acutely. Here, we found that mesenchymal stem cells from human umbilical cord (hUC-MSCs) could restore behavioral functions and attenuate the histopathological deficits of experimental autoimmune encephalomyelitis mice over the long term (i.e., 50 days) by suppression of perivascular immune cell infiltrations and reduction in both demyelination and axonal injury in the spinal cord. These findings suggest that transplantation of hUC-MSCs may be a potential therapy for MS.
Apoptosis of lens epithelial cell (LEC) plays an important role in cataract formation, and its prevention may be one of the therapeutic strategies in treating cataract. This study used human lens epithelial cell (hLEC) line SRA01/04 to investigate the protective effect and mechanism of phycocyanin on glactose-induced apoptosis in hLEC. hLECs were cultured in D/F(12)-10% FBS medium containing 125mM d-galactose with or without phycocyanin. Cell viability was assessed by methylthiazol tetrazolium (MTT) assay. Cell apoptosis was elevated with Wright-Giemsa staining, AO/EB double staining, and DNA fragmentation assay. Mitochondrial apoptosis-associated molecules and unfolded protein response-associated molecules from cultured SRA01/04 cells were quantified using protein blot analysis. The results demonstrated that phycocyanin suppressed SRA01/04 cells' morphologic changes and apoptosis induced by d-galactose, inhibited the expression and activation of caspase 3, alternated the Bax/Bcl-2 ratio, and down-regulated the level of p53, GRP78, and CHOP in d-galactose-treated SRA01/04 cells. These results suggest that phycocyanin might suppress d-galactose-induced hLEC apoptosis through two pathways: mitochondrial pathway, involving p53 and Bcl-2 family protein expression, and unfolded protein response pathway, involving GRP78 and CHOP expression.
PCBs, widespread and well-characterized endocrine disruptors, cause the disruption of thyroid hormone (TH) homeostasis in humans and animals. In order to verify the hypotheses that MAPK pathways would play roles in disturbance of TH levels caused by PCBs, and that TH-associated receptors could function in certain MAPK pathway, Sprague-Dawley rats were dosed with PCB153 intraperitoneally (i.p.) at 0, 4, 16 and 32mg/kg for 5 consecutive days, and Nthy-ori 3-1 cells were treated with PCB153 (0, 1, 5, 10μM) for 30min. Results showed that after the treatment with PCB153, serum total thyroxine (TT4), free thyroxine (FT4), total triiodothyronine (TT3) and thyrotropin releasing hormone (TRH) were decreased, whereas free triiodothyronine (FT3) and serum thyroid stimulating hormone (TSH) were not altered. In vivo and in vitro studies indicated that JNK pathway was activated after PCB153 exposure. Moreover, TRH receptor (TRHr) level was suppressed after the activation of JNK pathway and was elevated after the inhibition of JNK pathway, but TSH receptor (TSHr) level was not affected by the status of JNK pathway though it was reduced after PCB153 treatment. The activated signs of ERK and P38 pathways were not observed in this study. Taken together, observed effects suggested that JNK pathway could decrease TH levels via TRHr, and that would be one novel mechanism of PCB153-mediated disruption of THs.
mTORC1 inhibitors, including rapamycin and its analogs, have been actively studied both pre-clinically and clinically. However, the single treatment of mTORC1 inhibitors has been modest in most cancer types. We have previously demonstrated that the activation of PI3K/Akt and MEK/ERK signaling pathways attenuates the anticancer efficacy of mTORC1 inhibitors. In this study, we report that mTORC1 inhibition also phosphorylates and inactivates GSK3β, which is a tumor suppressor in lung cancer. Moreover, we show that perifosine, as an Akt inhibitor, decreases rapamycin-induced phosphorylation of GSK3β and elevated p-GSK3β levels in rapamycin-resistant cell lines. Combination of perifosine with mTORC1 inhibitors showed enhanced anticancer efficacy both in cell cultures and in a xenograft mouse model. In addition, perifosine inhibits the growth of both rapamycin sensitive and resistant A549 cells. However, inhibition of GSK3β by a selective inhibitor- LiCl, or downregulation of GSK3β expression by siRNA, reverses the growth inhibitory effects of perifosine on rapamycin resistant cells, suggesting the important role of GSK3β activation in enhancing mTORC1 inhibitors efficacy by perifosine. Thus, our results provide a potential therapeutic strategy to enhance mTORC1-targeted cancer therapy by using perifosine or targeting GSK3β.
Actinomycin D (Act D), a well known of clinical antitumor drug, has been used for the treatment of some highly malignant tumors, however, the clinical application was limited by its extreme cytotoxicity. In the present study, we reported that methylated actinomycin D (mAct D), a novel actinomycin D analog isolated from Streptomyces sp. KLBMP 2541 in our previous study, could not only exert stronger inhibitory effects on several human cancer cells than Act D in dose- and time-dependent manner at ng concentrations, especially on HepG2 cells, but also lower cytotoxicity in normal cells (HL-7702). Base on these results, HepG2 cells were treated for further study to illustrate the potential mechanism of mAct D. The results of nuclei morphology examination, DNA fragmentation detection, sub-G1 analysis, annexin V-FITC/PI staining and activation of caspase-3 indicated mAct D significantly induced HepG2 cells apoptosis. Semiquantitative RT-PCR and Western blot analysis revealed that mAct D induced apoptosis in HepG2 cells through mitochondria-dependent pathway by increasing levels of caspase-9, Bax, Bak while decreasing levels of Bcl-2, Bid, and Fas-dependent pathway by increasing levels of Fas, FasL, FADD, and caspase-8. Subsequently, pretreatment with specific inhibitor of caspase-8 Z-LEHD-FMK and caspase-9 Z-LEHD-FMK significantly attenuated caspase-3 activity, the cleavage of caspase-3 and PARP, meanwhile increased the cell viability. In addition, p53 and mitochondrial transcription factor A (mtTFA) were also upregulated. Taken together, ng concentrations mAct D induces the apoptosis of HepG2 through Fas- and mitochondria-mediated pathway and presents a potential novel alternative agent for the treatment of human hepatic carcinoma.
8-Methoxypsoralen (8-MOP), a naturally occurring compound, is a potent modulator of epidermal cell growth and differentiation in combination with ultraviolet light. However, there is little information on 8-MOP contribution to cell apoptosis alone. In the study, we evaluated 8-MOP, independently of its photoactivation, induced apoptosis in human hepatocellular carcinoma HepG2 cells. And we provide a molecular explanation linking 8-MOP to induce apoptosis. In HepG2 cells, treatment with 8-MOP induced the cell apoptosis in both dose-dependent and time-dependent manners. IC(50) values of 8-MOP were 8.775, 5.398 μM for 48 and 72 h, respectively. Further study showed that 8-MOP decreased the procaspase-3, procaspase-8, and procaspase-9, increased the ratio of Bax/Bcl-2 and decreased the survivin. Moreover, 8-MOP decreased differentiated embryonic chondrocyte gene1 (DEC1). Overexpression of DEC1 antagonized partially apoptosis induced by 8-MOP. And overexpression of DEC1 abolished the decrease of survivin and the activation of caspase-3 induced by 8-MOP partially. So, down regulation of DEC1 is involved in 8-MOP-induced apoptosis in HepG2 cells. Here, it is demonstrated that DEC1 possesses anti-apoptotic effects in 8-MOP-treated HepG2 cells. The findings provide more of a basis for 8-MOP as an anti-tumor agent in cancer therapy.
Nineteen natural compounds with diverse structures are identified as potential MMPIs using structure-based virtual screening from 4000 natural products. Hydroxycinnamic acid or analogs of natural products are important for potent inhibitory and selectivity against MMPs, and the solvent effect in the S1' pocket can affect the hydrophobic interactions and hydrogen bonds between MMPIs and MMPS, making MMPIs exhibit certain selectivity for a specific MMP isoenzyme. Furthermore, compound 5 can reduce the expression of both MMP-2 and active-MMP-9, and suppress the migration of MDA-MB-231 tumor cell in a wound healing assay, which may be further developed as an anticancer agent.
MicroRNAs (miRNAs) have been shown to play critical roles in regulating the progress of leukemia. We performed miRNA expression profile in six Chinese patients with chronic lymphocytic leukemia (CLL), and in peripheral B cells from pooled 30 healthy donors, using a platform containing 866 human miRNAs. The most frequent changes in miRNAs in CLL cells included downregulation of miR-126, miR-572, miR-494, miR-923, miR-638, miR-130a, miR-181a and miR-181b and up-regulation of miR-29a, miR-660, miR-20a, miR-106b, miR-142-5p, miR-101, miR-30b, miR-34a, miR-let-7f, miR-21 and miR-155. Among the miRNAs down-regulated in CLL cells, we showed that miR-181a/b expression levels were significantly lower in poor prognostic subgroups defined by unmutated immunoglobulin heavy chain variable status and p53 aberrations. Furthermore, under-expression of miR-181a and miR-181b was associated with shorter overall survival and treatment-free survival in CLL patients. We further evaluated fludarabine-induced apoptosis after transfection of primary CLL cells from 40 patients with miR-15a, miR-16-1, miR-34a, miR-181a and miR-181b mimics. Transfection of miR-34a, miR-181a and miR-181b mimics into CLL cells from p53 wild-type patients led to significant increase in apoptosis compared with miRNA control. However, enforced expression of these miRNAs had no effect on B-CLL cells from p53-attenuated patients. We further demonstrated that miR-181a and miR-181b inhibiting BCL-2, MCL-1 and X-linked inhibitor of apoptosis protein by direct binding to 3'UTR. Thus, these results suggest that miR-181a/b may play important roles in the pathogenesis of CLL and may provide a possible therapeutic avenue and a sensitive indicator of the activity of the p53 axis in CLL.
Hepatocellular carcinoma (HCC) is the third most common cancer worldwide, causing over 0.5 million deaths per year, with approximately half of these in China. Chemotherapy is the optimal treatment for patients with advanced HCC, although chemoresistance has become a significant obstacle to successful anti-cancer therapy. The expression of opsin3 (OPN3), also called encephalopsin or panopsin, is lower in 5-fluorouracil (5-FU)-resistant Bel7402(5-FU) cells compared to 5-FU-sensitive Bel7402 cells. To explore the role of OPN3 in 5-FU resistance, OPN3 overexpressing (Bel7402(5-FU)-OPN3) and knockdown (Bel7402-RNAi-OPN3) cell lines were generated. Bel7402(5-FU)-OPN3 cells were more sensitive to 5-FU treatment than controls, while OPN3 knockdown resulted in a significant increase in 5-FU resistance. This result was replicated in a second HCC cell line, HepG2. Further investigation of the mechanism revealed that decreased OPN3 levels in Bel7402(5-FU) cells activated the anti-apoptotic pathway through increasing phospho-Akt and the Bcl2/Bax ratio, while overexpression of OPN3 inactivated this pathway. Taken together, these results suggest that OPN3 depletion is involved in 5-FU resistance, and that therapeutic strategies targeting OPN3 may improve HCC sensitivity to chemotherapy.
Microcystin-RR (MC-RR) is a commonly encountered cyanotoxin and receives increasing attention due to the risk of its bioaccumulation in aquatic animals like fish. This study investigated the protein profiles of zebrafish (Danio rerio) testes after intraperitoneal injection (i.p.) with 0.5 LD(50) (2000 μg/kg). MC-RR caused a noticeable damage to testicular ultrastructure, showing widened intercellular junction, distention of mitochondria. The testes showed a rapid response of its defense systems to the oxidative stress caused by MC-RR. This is the first to use a proteomic approach to obtain an overview of the effects of MC-RR on the testes of zebrafish. The proteomic results revealed that toxin exposure remarkably altered the abundance of 24 proteins that were involved in cytoskeleton assembly, oxidative stress, glycolysis metabolism, calcium ion binding and other biological functions. In conclusion, MC-RR damaged the testes and was toxic to the reproductive system of male zebrafish mainly through causing oxidative stress.
microRNAs (miRNAs) are an abundant class of small noncoding RNAs that function primarily as oncogenes and tumor suppressors by mediating translational repression or mRNA degradation via binding target genes. In this study, malignant human bronchial epithelial cells transformed by anti-benzo[a]pyrene-trans-7,8-diol-9,10-epoxide were used to help characterize the possible mechanisms of miRNA function in chemical carcinogenesis. The expression level of miR-106a was measured by the real-time, reverse transcriptase polymerase chain reaction. We used the miR-106a inhibitor and the miR-106a mimic to downregulate or upregulate miR-106a activity in malignantly transformed cells to determine the effects of miR-106a on the biological properties of the cell. We observed overrepresentation of miR-106a in transformed cells compared with control cells. Silencing miR-106a by transfection with the miR-106a inhibitor suppressed cell proliferation, induced cell cycle arrest and apoptosis, and inhibited anchorage-independent growth and tumor growth in nude mice. Increasing miR-106a in malignantly transformed cells by transfection with the miR-106a mimic gave the opposite results. Moreover, untransformed cells showed a reduction of cell cycle arrest and apoptosis rate followed by transfection with the miR-106a mimic. Bioinformatic analysis showed that tumor suppressor RB1 is one of predictive targets of miR-106a. We confirmed this target by Western blot and dual luciferase assay. Our findings suggest that miR-106a might function as an oncogene in transformation induced by a chemical carcinogen. Thus, knock down of miR-106a in malignant cells is a potential therapeutic strategy.
The purpose of this study is to investigate the possible mechanism and the neuroprotective effect of human urinary kallidinogenase (HUK) in cerebral ischemia. The mouse middle cerebral artery occlusion (MCAO) model was used. Mice were treated with HUK (20 PNAU/g per day, intravenous) or saline as control, from the beginning of reperfusion to 72 h. Neurological deficits, infarct size, and BWC were measured at 6, 24, 48, and 72 h after MCAO, respectively. Pathological changes of brain were observed by TUNEL assay. Inflammatory factors were measured by real-time PCR and western blotting. Activation of MAPKs, Akt, and nuclear factor-kappaB (NF-kappaB) was detected by western blotting. Our results indicated that HUK significantly improved neurofunction, decreased infarct size, and suppressed edema, as well as inflammatory mediators as compared with the vehicle group. Furthermore, HUK inhibited the NF-kappaB pathway and activated the MAPK/ERK pathway in this neuroprotection.
AIMS:
Corosolic acid (CRA) is a natural triterpenoid with antioxidative activity. This study was designed to elucidate the mechanism through which CRA protected vessel endothelial homeostasis by combating oxidative stress.
RESULTS:
In endothelial cells, CRA induced dynamin-related protein 1 (Drp1) phosphorylation at Ser637 and thus inhibited mitochondrial fission in response to oxidative stress. It promoted AMP-activated protein kinase (AMPK) activity in an LKB1-dependent manner, and silencing AMPK abrogated its inhibitory effect on Drp1 activation and mitochondrial fission. CRA inhibited the translocation of p47(phox) and p67(phox) and the overexpression of gp91(phox) induced by palmitate (PA), demonstrating its action in suppression of NOX2 activation. Drp1 knockdown reduced PA-induced gp91(phox) expression, while Drp1 induction was also diminished by gp91(phox) knockdown, suggesting the reciprocal relationship between NOX2 and Drp1. Knockdown Drp1 or gp91(phox) attenuated PA-induced NLRP3 induction and enhanced inhibitory effects of CRA. Oral administration of CRA in high-fat diet mice reproduced similar regulation in the aorta endothelium, further confirming its protection on endothelial homeostasis in vivo.
INNOVATION:
This study demonstrated that the defect in mitochondrial morphology is associated with the oxidative stress and NLRP3 inflammasome activation in the endothelium. Drp1 and NOX2 regulated each other and worked together to induce NLRP3 inflammasome activation, suggesting that modulation of Drp1 phosphorylation (Ser637) might be a potential therapeutic target for combating oxidative stress in vessel diseases.
CONCLUSION:
CRA prevented mitochondrial fission by regulation of Drp1 phosphorylation (Ser637) in an AMPK-dependent manner, and this action contributed to blocking NOX2 oxidase signaling and suppressing NLRP3 inflammasome activation in the endothelium. Antioxid. Redox Signal. 24, 893-908.
SCOPE:
Quercetin is a dietary flavonoid whose role in the regulation of the activity of insulin remains controversial. Our study aimed to investigate how quercetin and its major metabolite quercetin-3-glucuronide (Q-3-G) regulate insulin-mediated glucose disposal in skeletal muscle under normal and inflammatory conditions.
METHODS AND RESULTS:
Under normal conditions, quercetin impaired glucose and insulin tolerance and attenuated insulin-mediated phosphorylation of Akt substrate of 160 kDa (AS160) and TBC1D1 without affecting Akt activity in male Institute of Cancer Research (ICR) mice. However, under inflammatory conditions, quercetin exhibited an opposite effect in these animals. In C2C12 cells, quercetin also decreased insulin-stimulated AS160 and TBC1D1 phosphorylation and glucose uptake in the absence of an inflammatory insult, whereas it improved the action of insulin under inflammatory conditions. Knockdown of adenosine 5'-monophosphate-activated protein kinase α (AMPKα) blocked the differential effects of quercetin under both conditions. Unlike quercetin, Q-3-G had no influence on insulin-induced phosphorylation of AS160 and TBC1D1 and glucose uptake in C2C12 myotubes under normal conditions. Q-3-G displayed a similar regulation with quercetin in glucose disposal under inflammatory conditions.
CONCLUSION:
Quercetin suppressed insulin-mediated glucose disposal in skeletal muscle tissue/cells under normal conditions while it ameliorated impaired glucose uptake under inflammatory conditions with activation of AMPK. In contrast, Q-3-G ameliorated insulin resistance in skeletal cells under inflammatory conditions without affecting glucose disposal under normal conditions.
© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
BACKGROUND AIMS:
Mesenchymal stromal cells (MSCs) and regulatory T cells (Treg) have been successfully used in treating autoimmune diseases accompanied by abundant inflammatory cytokines such as interferon (IFN)-γ and tumor necrosis factor (TNF)-α. Therefore, this work investigated the effects of IFN-γ and TNF-α on the ability of human placenta-derived mesenchymal stromal cells (hPMSCs) on inducing the differentiation of CD4(+)interleukin (IL)-10(+)and CD8(+)IL-10(+)Treg subsets.
METHODS:
Human PMSCs were co-cultured with T cells in the presence or absence of a trans-well system or anti- programmed death ligand-2 (PDL2) monoclonal antibody (mAb), respectively. CD4(+)IL-10(+)and CD8(+)IL-10(+)Treg subsets, as well as the levels of IL-10 in the supernatants, were detected on this basis. Examinations were conducted to explore the impact of IFN-γ and TNF-α on the expression of PDL2 in hPMSCs. In this process, flow cytometry, Western blot and reverse-transcriptase-polymerase chain reaction were used.
RESULTS:
CD4(+)IL-10(+)and CD8(+)IL-10(+)Treg subsets from T cells either non-activated or activated by use of phytohaemagglutinin (PHA) or CD3/CD28mAb significantly increased in the presence of hPMSCs. However, these levels markedly decreased after blocking the expression of PDL2 in hPMSCs. IL-10 followed the same pattern. Furthermore, the percentages of CD4(+)IL-10(+) and CD8(+)IL-10(+)T cells also sharply declined under the trans-well system, whereas the percentages as well as the expression of PDL2 in hPMSCs oppositely raised after hPMSCs pre-stimulated by IFN-γ and TNF-α. IFN-γ could promote the expression of PDL2 partly through the JAK/STAT signaling pathway.
CONCLUSIONS:
IFN-γ and TNF-α could promote the ability of hPMSCs in inducing the differentiation of CD4(+)IL-10(+)and CD8(+)IL-10(+)Treg subsets and enhance the expression of PDL2 in hPMSCs. These would benefit the application of hPMSCs in clinical trials.
Copyright © 2015 International Society for Cellular Therapy. Published by Elsevier Inc. All rights reserved.
BACKGROUND/AIMS:
8-Methoxypsoralen (8-MOP), a formerly considered photosensitizing agent, induces apoptosis when used alone. On this basis, the present study was designed to explore the effects and mechanisms of 8-MOP-induced apoptosis in human hepatocellular carcinoma HepG2 cells, independent of its photoactivation.
METHODS:
We analyzed the cell viability with MTT assay. Flow cytometry was used to examine the apoptosis rate, mitochondrial membrane potential (MMP) and reactive oxygen species (ROS) generation after specific staining. The expression and location of apoptosis-associated protein as well as the activation status of cell signaling pathway were determined by Western blot analysis.
RESULTS:
8-MOP significantly decreased cell viability and induced cell apoptosis through mitochondrial apoptotic pathway, as demonstrated by increased Bax/Bcl-2 ratio, collapsed MMP, and induced cytochrome c release (Cyt c) and apoptosis-inducing factor (AIF) transposition. ROS generation was significantly increased by 8-MOP and the eradication of ROS significantly abolished 8-MOP-induced apoptosis. In addition, the activation of ERK1/2 was drastically decreased by 8-MOP as ERK inhibitor PD98059, indicating a role of ERK1/2 signaling pathway in 8-MOP-induced cell apoptosis.
CONCLUSION:
8-MOP induces intrinsic apoptosis by increasing ROS generation and inhibiting ERK1/2 pathway in HepG2 cells. The findings are important in substantiating the anti-tumor role of 8-MOP in cancer therapy.
© 2015 S. Karger AG, Basel.
BACKGROUND AND PURPOSE:
This study aims to investigate whether and how pharmacological activation of AMP-activated protein kinase (AMPK) improves endothelial function by suppressing mitochondrial ROS-associated endoplasmic reticulum stress (ER stress) in the endothelium. Experimental approach Palmitate stimulation induced mitochondrial fission and ER stress-associated endothelial dysfunction. The effects of AMPK activators salicylate and AICA riboside (AICAR) on mitochondrial ROS production, Drp1 phosphorylation, mitochondrial fission, ER stress, thioredoxin-interacting protein (TXNIP)/NLRP3 inflammasome activation, inflammation, cell apoptosis and endothelium-dependent vasodilation were observed. Key results "Silencing" of TXNIP by RNA interference inhibited NLRP3 inflammasome activation in response to ER stress, indicating that TXNIP was a key link between ER stress and NLRP3 inflammasome activation. AMPK activators salicylate and AICAR prevented ROS-induced mitochondrial fission by enhancing dynamin-related protein 1 (Drp1) phosphorylation (Ser 637) and thereby attenuated IRE-1α and PERK phosphorylation, but their actions were blocked by knockdown of AMPK. Salicylate and AICAR reduced TXNIP induction and inhibited NLRP3 inflammasome activation by reducing NLRP3 and caspase-1 expression, leading to a reduction in IL-1β secretion. As a result, salicylate and AICAR inhibited inflammation and reduced cell apoptosis. Meanwhile, salicylate and AICAR enhanced eNOS phosphorylation and restored the loss of endothelium-dependent vasodilation in the rat aorta. Immunohistochemistry staining showed that AMPK activation inhibited ER stress and NLRP3 inflammasome activation in the vascular endothelium.
CONCLUSION AND IMPLICATIONS:
Pharmacological activation of AMPK regulated mitochondrial morphology and ameliorated endothelial dysfunction by suppression of mitochondrial ROS-associated ER stress and subsequent TXNIP/NLRP3 inflammasome activation. These findings suggested that regulation of Drp1 phosphorylation by AMPK activation contributed to suppression of ER stress and thus presented a potential therapeutic strategy for AMPK activation in the regulation of endothelium homeostasis.
Copyright © 2015 Elsevier Ltd. All rights reserved.
BACKGROUND:
Ribosome-binding protein 1 (RRBP1) has been implicated in the regulation of unfolded protein response, which is involved in almost every aspect of cancer development. We aimed to explore the significance of RRBP1 in the progression and prognosis of colorectal cancer (CRC).
METHODS:
The study population consisted of 856 patients with stage I-III CRC from two hospitals. RRBP1 expression was examined by immunohistochemistry (IHC) in colorectal tissues. The correlation of RRBP1 expression and CRC occurrence was assessed in paired cancer-adjacent tissues. Factors contributing to prognosis were evaluated in a training-validation design with univariate and multivariate Cox analysis. Colorectal cancer aggressiveness caused by RRBP1 knockdown or overexpression was evaluated in CRC cells.
RESULTS:
RRBP1 was aberrantly overexpressed in CRC. Compared with low-RRBP1 patients, high-RRBP1 patients had shorter disease-specific survival in the training (hazard ratio (HR), 2.423; 95% confidence interval (CI), 1.531-3.835) and validation cohorts (HR, 3.749; 95% CI, 2.166-6.448) in multivariate Cox analysis. High-RRBP1 independently predicted a shorter disease-free survival (HR, 4.821; 95% CI, 3.220-7.218) in the validation cohort. RRBP1 knockdown reduced the aggressiveness of CRC cells in vitro and inhibited the growth of CRC xenografts in vivo.
CONCLUSIONS:
High RRBP1 expression facilitates CRC progression and predicts an unfavourable post-operative prognosis.
OBJECTIVES:
Low survival rate of mesenchymal stem cells (MSCs) severely limited the therapeutic efficacy of cell therapy in the treatment of myocardial infarction (MI). Bcl-xL genetic modification might enhance MSC survival after transplantation.
METHODS:
Adult rat bone marrow MSCs were modified with human Bcl-xL gene (hBcl-xL-MSCs) or empty vector (vector-MSCs). MSC apoptosis and paracrine secretions were characterized using flow cytometry, TUNEL, and ELISA in vitro. In vivo, randomized adult rats with MI received myocardial injections of one of the three reagents: hBcl-xL-MSCs, vector-MSCs, or culture medium. Histochemistry, TUNEL, and echocardiography were carried out to evaluate cell engraftment, apoptosis, angiogenesis, scar formation, and cardiac functional recovery.
RESULTS:
In vitro, cell apoptosis decreased 43%, and vascular endothelial growth factor (VEGF), insulin-like growth factor-1 (IGF-1), and plate-derived growth factor (PDGF) increased 1.5-, 0.7-, and 1.2-fold, respectively, in hBcl-xL-MSCs versus wild type and vector-MSCs. In vivo, cell apoptosis decreased 40% and 26% in hBcl-xL-MSC group versus medium and vector-MSC group, respectively. Similar results were observed in cell engraftment, angiogenesis, scar formation, and cardiac functional recovery.
CONCLUSIONS:
Genetic modification of MSCs with hBcl-xL gene could be an intriguing strategy to improve the therapeutic efficacy of cell therapy in the treatment of heart infarction.
ETHNOPHARMACOLOGICAL RELEVANCE:
Astragaloside IV and cycloastragenol are present together in Astragalus membranaceus Moench (Fabaceae) and this study aims to simultaneously investigate their regulation of endothelial homeostasis in the setting of endoplasmic reticulum stress (ER stress).
MATERIAL AND METHODS:
We stimulated endothelial cells with palmitate (PA 100μM) to evoked ROS-associated ER stress and observed the effects of astragaloside IV and cycloastragenol on thioredoxin-interacting protein (TXNIP) expression, NLRP3 inflammasome activation and mitochondrion-dependent apoptosis.
RESULTS:
Astragaloside IV and cycloastragenol inhibited ROS generation and attenuated ER stress inducer IRE1α phosphorylation, indicating the inhibition of ROS-associated ER stress. In response to ER stress, TXNIP expression increased, accompanied with NLRP3 induction and increased IL-1β and IL-6 production, but these alternations were reversed by treatment with astragaloside IV and cycloastragenol, demonstrating the inhibitory effects of astragaloside IV and cycloastragenol on TXNIP/NLRP3 inflammasome activation. Inflammasome activation led to mitochondrial cell death in endothelial cells, whereas astragaloside IV and cycloastragenol restored the loss of the mitochondrial membrane potential with inhibition of caspase-3 activity, and thereby protected cells from ER stress-induced apoptosis. Astragaloside IV and cycloastragenol enhanced AMPK phosphorylation and AMPK inhibitor compound C diminished their beneficial effects, indicative of the potential role of AMPK in their regulation.
CONCLUSIONS:
Astragaloside IV and cycloastragenol suppressed ROS-associated ER stress and then inhibited TXNIP/NLRP3 inflammasome activation with regulation of AMPK activity, and thereby ameliorated endothelial dysfunction by inhibiting inflammation and reducing cell apoptosis. Simultaneous investigations further showed that astragaloside IV and cycloastragenol were equally effective in regulation of endothelial homeostasis.
Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.
BACKGROUND:
Natural products from plants have been proven to be important resources of antitumor agents. In this study, we exploited the antitumor activity of (E)-3-(4-chlorophenyl)-N-(7-hydroxy-6-methoxy-2-oxo-2H-chromen-3-yl) acrylamide (SC-III3), a newly synthesized derivative of scopoletin, by in vitro and in vivo experiments.
METHODS:
Human hepatocellular carcinoma cell line HepG2 cells and xenograft of HepG2 cells in BALB/c nude mice were used to investigate the effects of SC-III3 on hepatocellular cancers. Cell cycle arrest and apoptosis were analyzed by flow cytometry. Cell cycle arrest, apoptosis and ATM-Chk pathway-related proteins were characterized by western blot.
RESULTS:
SC-III3 selectively inhibited the viability of HepG2 cells without significant cytotoxicity against human normal liver cells LO2. In mouse xenograft model of HepG2 cells, SC-III3 showed a marked inhibition of tumor growth in a dose-dependent manner. Cell cycle analysis revealed that SC-III3 induced cells to accumulate in S phase, which was accompanied by a marked decrease of the expressions of cyclin A, cyclin B, cyclin E and Cdk2 proteins, the crucial regulators of S phase cell cycle. SC-III3 treatment resulted in DNA breaks in HepG2 cells, which might contribute to its S phase arrest. The S arrest and the activation of ATM-Chk1/Chk2-Cdc25A-Cdk2 pathways induced by SC-III3 in HepG2 cells could be efficiently abrogated by pretreatments of either Ku55933 (an inhibitor of ATM) or UCN-01 (an inhibitor of Chk1/Chk2). The activation of p53-p21 pathway by SC-III3 was also reversed by Ku55933 treatment. SC-III3 led to significant accumulation of intracellular reactive oxygen species (ROS), a breaker of DNA strand, in HepG2 cells but not LO2 cells. Pretreatment with N-acetyl-l-cysteine (NAC), a ROS scavenger, could reverse SC-III3-caused ROS accumulation, DNA damage, activation of signal pathways relevant to DNA damage, S phase arrest and cell viability decrease in HepG2 cells.
CONCLUSION:
SC-III3 is able to efficiently inhibit the growth of hepatocellular carcinoma through inducing the generation of intracellular ROS, DNA damage and consequent S phase arrest, but lack of significant cytotoxicity against normal liver cells. This compound deserves further studies as a candidate of anticancer drugs.
AIMS:
Myriocin is a fungal metabolite with antiviral activity, including influenza, hepatitis B, and hepatitis C viruses. We investigated whether myriocin has activity against human HSV-2, one of the most prevalent pathogens of sexually transmitted disease.
MAIN METHODS:
Cell culture systems were used to evaluate myriocin effect on HSV-2 infection. Plaque forming assay and immunoblotting studies were used to determine virus production and viral protein expression, respectively.
KEY FINDINGS:
Myriocin showed no cytotoxic effect at up to 5 μM. Myriocin treatment did not inhibit HSV-2 infection. Instead, the treatment resulted in accelerated replication of HSV-2 and increased titers of infectious virion. The effect was detected at concentrations as low as 3 nM and plateaued at approximately 30 nM. Myriocin at 30 nM increased HSV-2 production by approximately 1.7 logs. Myriocin also promoted HSV-1 infection but required higher concentrations. A time course study revealed that myriocin promoted HSV-2 infection by acceleration of virus replication. Unlike trichostatin A that promotes HSV-2 infection and histone modifications, myriocin treatment did not alter histone modifications. Myriocin is a well characterized inhibitor of sphingolipid biosynthesis pathway. Structurally different inhibitors of the pathway showed no effect on HSV-2 infection. Exogenous sphingolipids did not reverse the effect of myriocin on HSV-2 infection either.
SIGNIFICANCE:
We found that myriocin promotes HSV-2 replication at nanomolar concentrations with yet unknown mechanisms. Further studies may uncover novel mechanisms regulating HSV replication and targets of myriocin action. This may have potential application in enhancing efficacy of oncolytic HSV for cancer therapy and other diseases.
Copyright © 2014 Elsevier Inc. All rights reserved.
BACKGROUND:
Rapamycin has proven to be a neuroprotective agent in traumatic brain injury (TBI). However, there is a lack of data regarding the effect of rapamycin on apoptotic neuronal death after TBI. Thus, the present study was designed to detect the modulatory role of rapamycin on apoptosis and explore the potential involvement of the mammalian target of rapamycin (mTOR)-p53-Bax axis after TBI.
MATERIAL AND METHODS:
Neurologic severity score tests were performed to measure behavioral outcomes. The effect of rapamycin treatment on neuronal death was analyzed using immunofluorescence analysis of NeuN. Terminal deoxynucleotidyl transferase-mediated dUTP nick 3'-end labeling was performed to detect apoptotic cells. The expression of Bax and phosphorylated protein of p53 was detected using Western blotting analyses and immunofluorescence staining. Phosphorylated protein of the mTOR in the ipsilateral cortex was detected using Western blotting analyses.
RESULTS:
Rapamycin administration after TBI was associated with an increased number of neurons, decreased apoptosis index, and improved neurobehavioral function, which was potentially mediated by inactivation of the mTOR-p53-Bax axis.
CONCLUSIONS:
Rapamycin can protect neurons from apoptotic neuronal death after TBI. This study presents a new insight into the antiapoptosis mechanisms, which are responsible for the neuroprotection of rapamycin, with the potential involvement of the mTOR-p53-Bax axis.
Copyright © 2015 Elsevier Inc. All rights reserved.
AIM:
Cardiac sympathetic afferent reflex (CSAR) participates in sympathetic over-excitation. Superoxide anions and angiotensin II (Ang II) mechanisms are associated with sympathetic outflow and CSAR in the paraventricular nucleus (PVN). This study was designed to investigate whether PVN superoxide anions mediate CSAR and Ang II-induced CSAR enhancement response in fructose-induced insulin resistance (IR) rats.
METHODS:
CSAR was evaluated with the changes of renal sympathetic nerve activity (RSNA) and mean arterial pressure (MAP) responses to the epicardial application of capsaicin (CAP) in anaesthetized rats.
RESULTS:
Compared with Control rats, IR rats showed that CSAR, PVN NAD(P)H oxidase activity, superoxide anions, malondialdehyde (MDA), Ang II and AT1 receptor levels were significantly increased, whereas PVN superoxide dismutase (SOD) and catalase (CAT) activities were decreased. In Control and IR rats, PVN microinjection of superoxide anions scavengers tempol, tiron and PEG-SOD (an analogue of endogenous superoxide dismutase) or inhibition of PVN NAD(P)H oxidase with apocynin caused significant reduction of CSAR, respectively, but DETC (a superoxide dismutase inhibitor) strengthened the CSAR. PVN pre-treatment with tempol abolished, whereas DETC potentiated, Ang II-induced CSAR enhancement response. Moreover, PVN pre-treatment with tempol or losartan prevented superoxide anions increase caused by Ang II in IR rats.
CONCLUSION:
PVN superoxide anions mediate CSAR and Ang II-induced CSAR response in IR rats. In IR state, increased NAD(P)H oxidase activity and decreased SOD and CAT activities in the PVN promote superoxide anions increase to involve in CSAR enhancement. Ang II may increase NAD(P)H oxidase activity via AT1 receptor to induce superoxide anion production.
© 2014 Scandinavian Physiological Society. Published by John Wiley & Sons Ltd.
BACKGROUND AND OBJECT:
Silent mating type information regulation 2 homolog 1 (SIRT1) is a class III histone deacetylase and activates peroxisome proliferator-activated receptor-γ co-activator-1α (PGC-1α) which attenuates oxidative damage. Alpha-lipoic acid (ALA) has been proven to protect the rat brain against cerebral ischemia injury by reducing oxidative stress. However, the underlying mechanisms are poorly understood. In this study, we investigated the potential neuroprotection and the possible role of ALA in SIRT1 pathway.
METHODS:
Male CD-1 mice were randomly assigned to three groups: Sham, permanent middle cerebral artery occlusion (pMCAO) and ALA group (ALA, 50mg/kg). ALA was administered intraperitoneally 30min prior to ischemia in the ALA group. Neurological deficit, infarct volume, and brain edema were detected at 24h after cerebral ischemia. Immunohistochemistry, western blot and quantitative reverse transcription polymerase chain reaction (RT-qPCR) were used to detect the expression of SIRT1 and PGC-1α. Activities of superoxide dismutase (SOD) were measured by assay kits.
RESULTS:
Compared with the pMCAO group, the ALA group significantly ameliorated neurological deficit, lessened infarct volume and brain edema, increased the expression of SIRT1, PGC-1α and activities of SOD (P<0.05).
CONCLUSIONS:
ALA protected the mouse brain against ischemic damage, and this protection may be through up-regulating SIRT1-dependent PGC-1α expression.
Copyright © 2014 IBRO. Published by Elsevier Ltd. All rights reserved.
OBJECTIVE:
Investigate the therapeutic effect of regional arterial infusion (RAI) with Aspirin-Triggered Lipoxin A4 (ATL) in experimental severe acute pancreatitis (SAP) in rats.
MATERIALS AND METHODS:
SAP was induced by injection of 5% sodium taurocholate into the pancreatic duct. Rats with SAP were treated with ATL (the ATL group) or physiological saline (the SAP group) infused via the left gastric artery 30 min after injection of sodium taurocholate. The sham group was subjected to the same surgical procedure, though without induction of SAP. Serum levels of amylase, phospholipase A2 (PLA2), interleukin-1β (IL-1β), IL-6 and tumor necrosis factor-α (TNF-α) were measured at 12 and 24 h after induction of SAP. Ascitic fluid, the pancreatic index (wet weight ratio) and myeloperoxidase (MPO) levels in the pancreas were determined and histopathological findings were evaluated. The expression of intercellular adhesion molecule-1 (ICAM-1), platelet endothelial cell adhesion molecule-1 (PECAM-1), NF-κB p65, and heme oxygenase-1 (HO-1) in the pancreas were estimated by immunofluorescence and western blot, respectively.
RESULTS:
ATL rats had lower serum levels of TNF-α, IL-1β, and IL-6 (P<0.01), PLA2 (P<0.05), and amylase levels (P<0.05) studied as compared with the SAP group. The pancreatic index in the ATL group decreased only at 24 h as compared with the SAP group (P<0.05). The histopathological findings and MPO levels in the pancreas significantly decreased in the ATL group as compared to the SAP group (P<0.05 and P<0.01, respectively). Immunofluorescence and western blot showed that ATL attenuated the expression of NF-κB p65, ICAM-1 and PECAM-1 in the pancreas, and increased the expression of HO-1 in SAP animals.
CONCLUSIONS:
We demonstrated that RAI with ATL attenuated the severity of experimental SAP, maybe achieved by improving the expression of HO-1, and down-regulating the NF-κB signaling pathway, with decreased expression of ICAM-1 and PECAM-1 and reduced generation of pro-inflammatory cytokines.
BACKGROUND:
The 90-kDa heat shock protein HSP90AA1 is critical for the stability of several proteins that are important for tumor progression and thus, is a promising target for cancer therapy. Selenosemicarbazone metal complexes have been shown to possess anticancer activity through an unknown molecular mechanism.
METHODS:
The MTT assay, fluorescence-activated cell sorting, and fluorescent microscopy were used to analyze the mechanism of the anti-cancer activity of the selenosemicarbazone metal complexes. Additionally, RNA-seq was applied to identify transcriptional gene changes, and in turn, the signaling pathways involved in the process of 2-24a/Cu-induced cell death. Last, the expression of HSP90AA1, HSPA1A, PIM1, and AKT proteins in 2-24a/Cu-treated cells were investigated by western blot analysis.
RESULTS:
A novel selenosemicarbazone copper complex (2-24a/Cu) efficiently induced G2/M arrest and was cytotoxic in cancer cells. 2-24a/Cu significantly induced oxidative stress in cancer cells. Interestingly, although RNA-seq revealed that the transcription of HSP90AA1 was increased in 2-24a/Cu-treated cells, western blotting showed that the expression of HSP90AA1 protein was significantly decreased in these cells. Furthermore, down-regulation of HSP90AA1 led to the degradation of its client proteins (PIM1 and AKT1), which are also cancer therapy targets.
CONCLUSION:
Our results showed that 2-24a/Cu efficiently generates oxidative stress and down-regulates HSP90AA1 and its client proteins (PIM1, AKT1) in U2os and HeLa cells. These results demonstrate the potential application of this novel copper complex in cancer therapy.
BACKGROUND AND AIMS:
The transcription factor forkhead box A2 (FOXA2) plays a central role in the development of endoderm-derived organs. It has been reported that FOXA2 acts as a suppressor in many kinds of tumor. However, little is known about the role of FOXA2 in gastric cancer.
METHODS:
The expression of FOXA2 in gastric cancer tissue samples from 89 patients was assessed by immunohistochemistry, and the clinicopathological characteristics of the samples were analyzed. The human gastric cancer cell line, BGC-823, was used to investigate the effects of FOXA2 in gastric cancer in vitro and in vivo and the potential mechanism involved was explored.
RESULTS:
FOXA2 expression in human gastric cancer cell lines and human gastric cancer tissues was lower compared with the normal gastric epithelium cell line GES1 and normal adult gastric tissues, respectively. Patients with high FOXA2 expression level had longer 5-year overall survival than those with low FOXA2 expression level. FOXA2 markedly inhibited growth of BGC-823 cells accompanied with the cell cycle arrest and apoptosis. Infection of BGC-823 cells by FOXA2 lentivirus resulted in reduced cell tumorigenesis in vitro and in vivo. Moreover, expression of Mucin 5AC was up-regulated along with increased expression of exogenous FOXA2 in BGC-823 cells; in contrast, dedifferentiation markers, BMI, CD54 and CD24, were down-regulated.
CONCLUSIONS:
These results suggest that FOXA2 induces the differentiation of gastric cancer and highlight FOXA2 as a novel therapeutic target and prognostic marker for human gastric cancer.
PURPOSE:
Lysine-specific demethylase 1 (LSD1) was highly expressed in several malignancies and had been implicated in pathological processes of cancer cells. However, the role of LSD1 in colorectal cancer (CRC) carcinogenesis, prognosis and treatment remains uncharacterized.
METHODS:
In this study, we examined LSD1 expression in paraffin-embedded CRC specimens from 295 patients, including 65 patients with paired samples of colorectal carcinoma, adjacent adenoma and normal colorectal tissues. Using an LSD1 inhibitor, CBB1003, as a probe, we studied the association between LSD1 and leucine-rich repeat-containing G-protein-coupled receptor 5 (LGR5), a CRC stem cell marker involved in carcinogenesis. The anti-tumor effects of CBB1003 on CRC cells were also examined.
RESULTS:
LSD1 expression was significantly elevated in colorectal tumor tissues compared with adjacent adenoma and normal colorectal tissues (P < 0.001), and LSD1 levels were significantly correlated with an advanced AJCC T stage (P = 0.012) and distant metastasis (P = 0.004). CBB1003 inhibited CRC cell proliferation and colony formation. In cultured CRC cells, inhibiting LSD1 activity by CBB1003 caused a decrease in LGR5 levels while overexpression of LGR5 reduced CBB1003-induced cell death. We also observed the inactivation of β-catenin/TCF signaling after CBB1003 treatment, consistent with the positive correlations among LSD1, LGR5, β-catenin and c-Myc expression in human colon tumor and adenoma tissues.
CONCLUSION:
Our result suggested that LSD1 overexpression promotes CRC development and that the LSD1 inhibitor inhibits CRC cell growth by down-regulating LGR5 levels and inactivates the Wnt/β-catenin pathway. Thus, LSD1 and its inhibitor might provide a new target or a useful strategy for therapy of CRC.
BACKGROUNDS AND AIMS:
Prion diseases are a group of infectious neurodegenerative diseases characterized by neuronal death and degeneration. Human leukocyte antigen-B-associated transcript 3 (BAT3) is an important apoptosis regulator. We therefore investigated the interactions between BAT3 and prion protein and the potential role of BAT3 in PrP106-126-induced apoptosis.
METHODS:
BAT3 and prion protein were overexpressed in Hela, Neuro2A, or primary neuronal cells by transfection with BAT3-HA or PRNP-EGFP expression plasmids and their relationship studied by immunofluorescence and Western blotting. The effect of BAT3 on PrP106-126-induced cytotoxicity and apoptosis was detected by the CCK-8 assay and terminal-deoxynucleotidyl transferase-mediated nick end labeling (TUNEL) assay. The expression of cytochrome c and Bcl-2 was examined by Western blotting.
RESULTS:
BAT3 interacted with prion protein and enhanced PrP expression. After PrP106-126 peptide treated, BAT3 was transported from the nucleus to cytoplasm, increased cell viability, and protected neurons from PrP106-126-induced apoptosis through stabilizing the level of Bcl-2 protein and inhibiting the release of cytochrome c to cytoplasm.
CONCLUSIONS:
Our present data showed a novel molecular mechanism of PrP106-126-induced apoptotic process regulation through the overexpression of BAT3, which may be important for the basic regulatory mechanism of neuron survival in prion diseases and associated neurodegenerative diseases in vivo.
© 2014 John Wiley & Sons Ltd.
BACKGROUND:
Resveratrol has been shown to attenuate cerebral vasospasm after subarachnoid hemorrhage (SAH); however, no study has explored its neuroprotective effect in early brain injury (EBI) after experimental SAH. The aim of this study was to evaluate the antiapoptotic function of resveratrol in EBI and its relationship with the PI3K/Akt survival pathway.
METHODS:
Experimental SAH was induced in adult male rats by prechiasmatic cistern injection. Control and SAH rats were divided into six groups and treated with low (20 mg/kg) or high (60 mg/kg) concentrations of resveratrol with or without LY294002 cotreatment. Brain samples of the rats were analyzed by immunohistochemistry, immunofluorescence staining, Western blotting, and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) apoptosis assays.
RESULTS:
High-concentration but not low-concentration resveratrol treatment in SAH rats led to a significant increase in phosphorylated Akt (p-Akt) protein levels compared with SAH rats without treatment. In addition, p-Akt-positive cells mainly colocalized with NeuN-positive cells. Neuronal apoptosis in SAH rat brain was attenuated by high-concentration resveratrol treatment. The antiapoptotic effect of resveratrol in SAH rats could be partially abrogated by the PI3K/Akt signaling inhibitor LY294002.
CONCLUSIONS:
Our results show that resveratrol has an antiapoptotic effect in EBI and that resveratrol might act through the PI3K/Akt signaling pathway.
Copyright © 2014 Elsevier Inc. All rights reserved.
OBJECTIVE:
Cardiac hypertrophy is a compensatory response of the heart to maintain its pumping capacity. Cardiac hypertrophy can be divided into pathological hypertrophy and physiological hypertrophy. The major forms of physiological hypertrophy include developing in response to developmental maturation, exercise, and pregnancy, which is adaptive and beneficial. Exercise has well-known beneficial cardiovascular effects and has recently been shown to be protective for myocardial ischemia-reperfusion injury. However, there are conflicting reports for the cardiac protective effects of pregnancy-induced hypertrophy. In the present study, we investigated the effects of pregnancy-induced physiological hypertrophy in cardiac ischemia-reperfusion injury and if cardiac progenitor cells were activated during pregnancy.
METHODS:
Physiological hypertrophy was induced in pregnancy and the mRNA levels of atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) were determined by real-time polymerase chain reactions (RT-PCRs) analysis. Triphenyltetrazolium chloride staining was used to determine the cardiac ischemia-reperfusion injury. c-Kit and Nkx2.5 levels were determined by RT-PCRs, western blot and immunofluorescent staining.
RESULTS:
Heart weight (HW) and the ratio of HW to tibia length were increased while mRNA levels of ANP and BNP remained unchanged. Pregnancy-induced physiological hypertrophy protected against cardiac ischemia-reperfusion injury. In pregnancy, c-Kit positive cardiac progenitor cells were activated.
CONCLUSION:
This study presents that pregnancy-induced physiological hypertrophy activates cardiac progenitor cells and thereafter protects against cardiac ischemia-reperfusion injury.
BACKGROUND AND PURPOSE:
Genistein is an isoflavone phytoestrogen found in a number of plants such as soybeans and there is accumulating evidence that it has beneficial effects on the regulation of glucose homeostasis. In this study we evaluated the effect of genistein on glucose homeostasis and its underlying mechanisms in normal and insulin-resistant conditions.
EXPERIMENTAL APPROACH:
To induce insulin resistance, mice or differentiated 3T3-L1 adipocytes were treated with macrophage-derived conditioned medium. A glucose tolerance test was used to investigate the effect of genistein. Insulin signalling activation, glucose transporter-4 (GLUT4) translocation and AMP-activated PK (AMPK) activation were detected by Western blot analysis or elisa.
KEY RESULTS:
Genistein impaired glucose tolerance and attenuated insulin sensitivity in normal mice by inhibiting the insulin-induced phosphorylation of insulin receptor substrate-1 (IRS1) at tyrosine residues, leading to inhibition of insulin-mediated GLUT4 translocation in adipocytes. Mac-CM, an inflammatory stimulus induced glucose intolerance accompanied by impaired insulin sensitivity; genistein reversed these changes by restoring the disturbed IRS1 function, leading to an improvement in GLUT4 translocation. In addition, genistein increased AMPK activity under both normal and inflammatory conditions; this was shown to contribute to the anti-inflammatory effect of genistein, which leads to an improvement in insulin signalling and the amelioration of insulin resistance.
CONCLUSION AND IMPLICATIONS:
Genistein showed opposite effects on insulin sensitivity under normal and inflammatory conditions in adipose tissue and this action was derived from its negative or positive regulation of IRS1 function. Its up-regulation of AMPK activity contributes to the inhibition of inflammation implicated in insulin resistance.
© 2013 The British Pharmacological Society.
AIM:
To investigate the effects of anti-ABCG2 monoclonal antibodies (mAbs) in combination with paclitaxel iron oxide nanoparticles (PTX-NPs) on CD138(-)CD34(-) multiple myeloma (MM) cancer stem cells (CSCs) in JJN3 cells.
MATERIALS & METHODS:
PTX-NPs were prepared using the hydrophobic interaction of the polyoxypropylene chain and oleic acid on the surface of iron oxide NPs and were targeted to the ABCG2 transporter overexpressing MM CSCs with mAbs.
RESULTS:
The data showed that MM CSCs have strong drug resistance and tumorigenicity compared with non-MM CSCs. PTX-NPs combined with mAbs led to a significant reduction in the tumor volume, a visible alleviation of lytic bone lesions and a markedly increased survival rate in contrast to using a single agent in MM CSCs when it was transplanted to nonobese diabetic/severe combined immunodeficiency mice.
CONCLUSION:
This study is the first to report on the anti-MM CSC activity by PTX-NPs as a single agent or used together with anti-ABCG2 mAbs to treat MM. These findings provide a rationale for future clinical trials.
BACKGROUND:
Research has shown reduced expression levels of miR-154 in prostate cancer (CaP). However, the function and molecular mechanisms of miR-154 in this cancer type remains unknown.
OBJECTIVE:
The aims of this study were to examine the functional significance of miR-154 in CaP cells and to identify the novel molecular targets regulated by miR-154.
MATERIALS AND METHODS:
miR-154 expression significantly decreased in primary CaP samples compared with nonmalignant samples measured by quantitative reverse transcription polymerase chain reaction. Restoration of miR-154 lowered the potential of CaP cell lines to grow and proliferate in vitro evaluated by CCK-8 assay, colony formation assay, and flow cytometry. miR-154 down-regulated the expression of CCND2 by binding to its 3'-untranslated region by luciferase reporter assay.
CONCLUSIONS:
miR-154 plays a prominent role in CaP proliferation by suppressing CCND2, and it may provide a new approach to the treatment of CaP.
Copyright © 2014. Published by Elsevier Inc.
AIM:
To determine the therapeutic effects of adrenomedullin (ADM) on vascular calcification and related molecular mechanism in fructose-induced insulin resistance rats.
METHODS:
Rats received ordinary drinking water or 10% fructose in drinking water for 12 weeks and subcutaneous injection of normal saline or ADM (3.6 μg kg(-1) ) twice a day for the last 4 weeks. Levels of ADM, calcitonin receptor-like receptors (CRLR), receptor activity-modifying proteins (RAMP) as well as calcium content, alkaline phosphatase (ALP) activity, osteoblastic and contractile smooth muscle markers in aortic media were measured.
RESULTS:
The levels of ADM, CRLR, RAMP2 and RAMP3 in aortic media were increased in fructose-fed rats. ADM treatment attenuated the fructose-induced insulin resistance, increased blood pressure, fasting glucose, insulin, triglycerides and cholesterol levels. It improved VSMCs proliferation and disordered arrangement and hyperplasia of elastic fibres in fructose-fed rats. Calcium deposits, calcium content and ALP activity in the aortic media were increased in fructose-fed rats, which were attenuated by ADM treatment. The osteoblastic markers such as osteopontin (OPN), bone morphogenetic protein 2 (BMP2) proteins and core binding factor alpha-1 (Cbfα-1) protein and mRNA expressions were increased in fructose-fed rats. ADM treatment increased the OPN protein expression, but reduced the BMP2 protein, Cbfα-1 protein and mRNA expression. Contractile smooth muscle markers such as α-actin and smooth muscle 22α (SM-22α) were downregulated in fructose-fed rats, which were recovered by ADM treatment.
CONCLUSION:
Administration of ADM attenuates insulin resistance, calcium deposition and osteogenic transdifferentiation in aortic media in fructose-fed rats.
© 2012 The Authors Acta Physiologica © 2012 Scandinavian Physiological Society.
BACKGROUND/AIMS:
ω3-polyunsaturated fatty acids (ω3- PUFAs) are known to possess anticancer properties. However, the relationship between ω3-PUFAs and β-catenin, one of the key components of the Wnt signaling pathway, in human pancreatic cancer remains poorly characterized.
METHODS:
Human pancreatic cancer cells (SW1990 and PANC-1) were exposed to two ω3-PUFAs, docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), to investigate the relationship between ω3-PUFAs and the Wnt/β-catenin signaling pathway in vitro. Mouse pancreatic cancer (PANC02) cells were implanted into fat-1 transgenic mice, which express ω3 desaturases and result in elevated levels of ω3-PUFAs endogenously. The tumor size, levels of Wnt/β-catenin signaling molecules and apoptosis levels were analyzed to examine the influence of ω3-PUFAs in vivo.
RESULTS:
DHA and EPA significantly inhibited cell growth and increased cell death in pancreatic cancer cells. DHA also reduced β-catenin expression, T cell factor/lymphoid-enhancing factor reporter activity and induced β-catenin/Axin/GSK-3β complex formation, a known precursor to β-catenin degradation. Furthermore, Wnt3a, a natural canonical Wnt pathway ligand, reversed DHA-induced growth inhibition in PANC-1 cells. Immunohistochemical analysis showed aberrant upregulation and increased nuclear staining of β-catenin in tumor tissues from pancreatic cancer patients. However, β-catenin levels in tumor tissues from fat-1 transgenic mice were reduced with a significant increase in apoptosis compared with those from control mice.
CONCLUSION:
ω3-PUFAs may be an effective therapy for the chemoprevention and treatment of human pancreatic cancer. and IAP.
Copyright © 2011 S. Karger AG, Basel.
PURPOSE:
MicroRNAs (miRNAs) are short non-coding RNA molecules, which post-transcriptionally regulate genes expression and play crucial roles in diverse biological processes. Recent studies have shown that dysregulation of miRNAs might modulate the resistance of cancer cells to anti-cancer drugs, yet the modulation mechanism is not fully understood. We aimed to investigate the possible role of miRNAs in the development of multidrug resistance (MDR) in human gastric and lung cancer cell lines.
METHODS:
miRNA Quantitative real-time PCR was used to detect the different miRNA expression levels between drug resistant and parental cancer cells. MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay was used to test the drug-resistant phenotype changes in cancer cells via over or downregulation of miRNAs. Dual-luciferase activity assay was used to verify the target genes of miRNAs. Western blot analysis and apoptosis assay were used to elucidate the mechanism of miRNAs on modulating drug resistance in cancer cells.
RESULTS:
miR-200bc/429 cluster was downregulated, while BCL2 and XIAP were upregulated in both MDR SGC7901/VCR (vincristine) and A549/CDDP (cisplatin) cells, compared with the parental SGC7901 and A549 cells, respectively. Overexpression of miR-200bc/429 cluster sensitized SGC7901/VCR and A549/CDDP cells to anti-cancer drugs, respectively. Both BCL2 and XIAP 3'-UTR reporters constructed in MDR cells suggested that BCL2 and XIAP were the common target genes of the miR-200bc/429 cluster. Enforced miR-200bc/429 cluster expression reduced BCL2 and XIAP protein level and sensitized both MDR cells to VCR-induced and CDDP-induced apoptosis, respectively.
CONCLUSIONS:
Our findings first suggest that miR-200bc/429 cluster could play a role in the development of MDR in both gastric and lung cancer cell lines, at least in part by modulation of apoptosis via targeting BCL2 and XIAP.
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