Anti-ERK1/2 (phospho-T202/Y204) Antibody (A27806)

Triple negative breast cancer (TNBC) accounts for 10-15% of all breast cancer but is responsible for a disproportionate share of morbidity and mortality because of its aggressive characteristics and lack of targeted therapies. Chemotherapy induces enrichment of breast cancer stem cells (BCSCs), which are responsible for tumor recurrence and metastasis. Here, we demonstrate that chemotherapy induces the expression of the cystine transporter xCT and the regulatory subunit of glutamate-cysteine ligase (GCLM) in a hypoxia-inducible factor (HIF)-1-dependent manner, leading to increased intracellular glutathione levels, which inhibit mitogen-activated protein kinase kinase (MEK) activity through copper chelation. Loss of MEK-ERK signaling causes FoxO3 nuclear translocation and transcriptional activation of the gene encoding the pluripotency factor Nanog, which is required for enrichment of BCSCs. Inhibition of xCT, GCLM, FoxO3, or Nanog blocks chemotherapy-induced enrichment of BCSCs and impairs tumor initiation. These results suggest that, in combination with chemotherapy, targeting BCSCs by inhibiting HIF-1-regulated glutathione synthesis may improve outcome in TNBC.

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.

Pain patients who are nicotine dependent report a significantly increased incidence and severity of pain intensity. The goal of this study was to determine the effects of prolonged nicotine administration on inflammatory proteins implicated in the development of peripheral and central sensitization of the trigeminal system. Behavioral, immunohistochemical, and microarray studies were utilized to investigate the effects of nicotine administered daily for 14 days via an Alzet® osmotic pump in Sprague Dawley rats. Systemic nicotine administration caused a significant increase in nocifensive withdrawals to mechanical stimulation of trigeminal neurons. Nicotine stimulated expression of the pro-inflammatory signal transduction proteins phosphorylated-extracellular signal-regulated kinase (p-ERK), phosphorylated-c-Jun N-terminal kinase (p-JNK), and protein kinase A (PKA) in the spinal trigeminal nucleus. Nicotine also promoted elevations in the expression of glial fibrillary acidic protein (GFAP), a biomarker of activated astrocytes, and the microglia biomarker ionized calcium-binding adapter molecule 1 (Iba1). Similarly, levels of eleven cytokines were significantly elevated with the largest increase in expression of TNF-α. Levels of PKA, p-ERK, and p-JNK in trigeminal ganglion neurons were increased by nicotine. Our findings demonstrate that prolonged systemic administration of nicotine promotes sustained behavioral and cellular changes in the expression of key proteins in the spinal trigeminal nucleus and trigeminal ganglion implicated in the development and maintenance of peripheral and central sensitization.

The protein tyrosine phosphatase 1B (PTP1B), a non-transmembrane protein tyrosine phosphatase, has been implicated in gastric pathogenesis. Several lines of recent evidences have shown that PTP1B is highly amplified in breast and prostate cancers. The aim of this study was to investigate PTP1B amplification in gastric cancer and its association with poor prognosis of gastric cancer patients, and further determine the role of PTP1B in gastric tumorigenesis. Our data demonstrated that PTP1B was significantly up-regulated in gastric cancer tissues as compared with matched normal gastric tissues by using quantitative RT-PCR (qRT-PCR) assay. In addition, copy number analysis showed that PTP1B was amplified in 68/131 (51.9%) gastric cancer cases, whereas no amplification was found in the control subjects. Notably, PTP1B amplification was positively associated with its protein expression, and was significantly related to poor survival of gastric cancer patients. Knocking down PTP1B expression in gastric cancer cells significantly inhibited cell proliferation, colony formation, migration and invasion, and induced cell cycle arrested and apoptosis. Mechanically, PTP1B promotes gastric cancer cell proliferation, survival and invasiveness through modulating Src-related signaling pathways, such as Src/Ras/MAPK and Src/phosphatidylinositol-3-kinase (PI3K)/Akt pathways. Collectively, our data demonstrated frequent overexpression and amplification PTP1B in gastric cancer, and further determined the oncogenic role of PTP1B in gastric carcinogenesis. Importantly, PTP1B amplification predicts poor survival of gastric cancer patients.

There is an urgent clinical need for safe and effective treatment agents and therapy targets for estrogen receptor negative (ER-) breast cancer. G protein-coupled receptor 30 (GPR30), which mediates non-genomic signaling of estrogen to regulate cell growth, is highly expressed in ER--breast cancer cells. We here showed that activation of GPR30 by the receptor-specific agonist G-1 inhibited the growth of ER--breast cancer cells in vitro. Treatment of ER--breast cancer cells with G-1 resulted in G2/M-phase arrest, downregulation of G2-checkpoint regulator cyclin B, and induction of mitochondrial-related apoptosis. The G-1 treatment increased expression of p53 and its phosphorylation levels at Serine 15, promoted its nuclear translocation, and inhibited its ubiquitylation, which mediated the growth arrest effects on cell proliferation. Further, the G-1 induced sustained activation and nuclear translocation of ERK1/2, which was mediated by GPR30/epidermal growth factor receptor (EGFR) signals, also mediated its inhibition effects of G-1. With extensive use of siRNA-knockdown experiments and inhibitors, we found that upregulation of p21 by the cross-talk of GPR30/EGFR and p53 was also involved in G-1-induced cell growth arrest. In vivo experiments showed that G-1 treatment significantly suppressed the growth of SkBr3 xenograft tumors and increased the survival rate, associated with proliferation suppression and upregulation of p53, p21 while downregulation of cyclin B. The discovery of multiple signal pathways mediated the suppression effects of G-1 makes it a promising candidate drug and lays the foundation for future development of GPR30-based therapies for ER- breast cancer treatment.

Insulin-like growth factor (IGF) signaling is involved in oral squamous cell carcinoma (OSCC), but IGF-1 receptor (IGF-1R)-mediated intricate regulatory networks among molecular interactions and signalling path ways in OSCC remain unclear. Here, we found that overexpression of IGF-1R and insulin receptor substrate-2 (IRS-2) was negatively associated with histological differentiation. IGF signaling stimulated OSCC cell growth. Conversely, overexpression of let-7b inhibited proliferation and colony formation and triggered S/G2 cell cycle arrest by targeting IGF-1R and IRS-2 through the Akt pathway. Also, the inverse relationship between expression of let-7b and IGF-1R/IRS-2 was confirmed in OSCC tumor xenografts and clinical specimens. Furthermore, by activating ERK1/2, IGF-1R transcriptionally upregulated IRS-2. Our results indicate that let-7b/IGF-1R-mediated crosstalk between IRS-2/Akt and MAPK is involved in OSCC and is a potential therapeutic target for therapy.

Cyclin-dependent kinase 5 is a proline-directed serine/threonine kinase and its activity participates in the regulation of nociceptive signaling. Like binding with the activators (P35 or P25), the phosphorylation of Cdk5 plays a critical role in Cdk5 activation. However, it is still unclear whether Cdk5 phosphorylation (p-Cdk5) contributes to pain hyperalgesia. The aim of our current study was to identify the roles of p-Cdk5 and its upstream regulator in response to peripheral inflammation. Complete Freund's adjuvant (CFA) injection induced acute peripheral inflammation and heat hyperalgesia, which was accompanied by sustained increases in phospho-ERK1/2 (p-ERK1/2) and phospho-Cdk5(S159) (p-Cdk5(S159)) in the spinal cord dorsal horn (SCDH). CFA-induced p-ERK primarily colocalized with p-Cdk5(S159) in superficial dorsal horn neurons. Levels in p-ERK and p-Cdk5 were also increased in the 2(nd) phase of hyperalgesia induced by formalin injection, which can produce acute and tonic inflammatory pain. MAP kinase kinase inhibitor U0126 intrathecal delivery significantly suppressed the elevation of p-Cdk5(S159), Cdk5 activity and pain response behavior (Heat hyperalgesia, Spontaneous flinches) induced by CFA or formalin injection. Cdk5 inhibitor roscovitine intrathecal administration also suppressed CFA-induced heat hyperalgesia and Cdk5 phosphorylation, but did not attenuate ERK activation. All these findings suggested that p-Cdk5(S159) regulated by ERK pathway activity may be a critical mechanism involved in the activation of Cdk5 in nociceptive spinal neurons contributes to peripheral inflammatory pain hypersensitivity.

Cancer-associated fibroblasts (CAFs) are crucial co-mediators of breast cancer progression. Estrogen is the predominant driving force in the cyclic regulation of the mammary extracellular matrix, thus potentially affecting the tumor-associated stroma. Recently, a third estrogen receptor, estrogen (G-protein-coupled) receptor (GPER), has been reported to be expressed in breast CAFs. In this study, GPER was detected by immunohistochemical analysis in stromal fibroblasts of 41.8% (59/141) of the primary breast cancer samples. GPER expression in CAFs isolated from primary breast cancer tissues was confirmed by immunostaining and RT-PCR analyses. Tamoxifen (TAM) in addition to 17β-estradiol (E₂) and the GPER agonist G1 activated GPER, resulting in transient increases in cell index, intracellular calcium, and ERK1/2 phosphorylation. Furthermore, TAM, E₂, and G1 promoted CAF proliferation and cell-cycle progression, both of which were blocked by GPER interference, the selective GPER antagonist G15, the epidermal growth factor receptor (EGFR) inhibitor AG1478, and the ERK1/2 inhibitor U0126. Importantly, TAM as well as G1 increased E₂ production in breast CAFs via GPER/EGFR/ERK signaling when the substrate of E₂, testosterone, was added to the medium. GPER-induced aromatase upregulation was probably responsible for this phenomenon, as TAM- and G1-induced CYP19A1 gene expression was reduced by GPER knockdown and G15, AG1478, and U0126 administration. Accordingly, GPER-mediated CAF-dependent estrogenic effects on the tumor-associated stroma are conceivable, and CAF is likely to contribute to breast cancer progression, especially TAM resistance, via a positive feedback loop involving GPER/EGFR/ERK signaling and E₂ production.

Hippocampal neurons play a critical role in learning and memory; however, the effects of environmental mechanical forces on neurite extension and associated underlying mechanisms are largely unexplored, possibly due to difficulties in maintaining central nervous system neurons. Neuron adhesion, neurite length, and mechanotransduction are mainly influenced by the extracellular matrix (ECM), which is often associated with structural scaffolding. In this study, we investigated the relationship between substrate stiffness and hippocampal neurite outgrowth by controlling the ratios of polydimethylsiloxane (PDMS) base to curing agent to create substrates of varying stiffness. Immunostaining results demonstrated that hippocampal neurons have longer neurite elongation in 35:1 PDMS substrate compared those grown on 15:1 PDMS, indicating that soft substrates provide a more optimal stiffness for hippocampal neurons. Additionally, we discovered that pPKCα expression was higher in the 15:1 and 35:1 PDMS groups than in the poly-L-lysine-coated glass group. However, when we used a fibronectin (FN) coating, we found that pFAKy397 and pFAKy925 expression were higher in glass group than in the 15:1 or 35: 1 PDMS groups, but pPKCα and pERK1/2 expression were higher in the 35:1 PDMS group than in the glass group. These results support the hypothesis that environmental stiffness influences hippocampal neurite outgrowth and underlying signaling pathways.

Extracellular signal-regulated kinase (ERK) belongs to the mitogen-activated protein kinases (MAPK) superfamily. Aberrant upregulation and activation of ERK cascades may often lead to tumor cell development. However, how ERK is involved in tumor progression is yet to be defined. In current study, we described that ERK undergoes S-nitrosylation by nitric oxide (NO). ERK S-nitrosylation inhibits its phosphorylation and triggers apoptotic program as verified by massive apoptosis in fluorescence staining. The proapoptotic effect of NO induced S-nitrosylation is reversed by NO scavenger Haemoglobin (HB). Furthermore, an S-nitrosylation dead ERK mutant C183A also demolishes the proapoptotic potential of NO and favors cell survival. Therefore, Cys(183) might be a potential S-nitrosylation site in ERK. In addition, S-nitrosylation is a general phenomenon that regulates ERK activity. These findings identify a novel link between NO-mediated S-nitrosylation and ERK regulation, which provide critical insights into the control of apoptosis and tumor development.

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.

MicroRNAs (miRNAs) are known to play a vital role in colorectal cancer. We found a widespread disruption in miRNA expression during colorectal tumorigenesis using microarray and quantitative RT-PCR analysis; of the 161 miRNAs altered in colorectal cancer compared with normal adjacent tissue samples, miR-31 was the most significantly dysregulated. We identified candidate targets of miR-31 using bioinformatics approaches and validated RAS p21 GTPase activating protein 1 (RASA1) as a direct target. First, we found an inverse correlation between miR-31 and RASA1 protein levels in vivo. Second, in vitro evidence demonstrated that RASA1 expression was significantly decreased by treatment with pre-miR-31-LV, whereas anti-miR-31-LV treatment increased RASA1 protein levels. Third, a luciferase reporter assay confirmed that miR-31 directly recognizes a specific location within the 3'-untranslated region of RASA1 transcripts. Furthermore, the biological consequences of miR-31 targeting RASA1 were examined by the cell proliferation assay in vitro and by the immunodeficient mouse xenograft tumor model in vivo. Taken together, our results demonstrate for the first time that miR-31 plays a significant role in activating the RAS signaling pathway through the inhibition of RASA1 translation, thereby improving colorectal cancer cell growth and stimulating tumorigenesis.

The regulation of neurite outgrowth is crucial in developing strategies to promote neurite regeneration after nerve injury and in degenerative diseases. In this study, we demonstrate that overexpression of an adaptor/scaffolding protein SH2B1β promotes neurite re-growth of differentiated PC12 cells, an established neuronal model, using wound healing (scraping) assays. Cell migration and the subsequent remodeling are crucial determinants during neurite regeneration. We provide evidence suggesting that overexpressing SH2B1β enhances protein kinase C (PKC)-dependent cell migration and phosphatidylinositol 3-kinase (PI3K)-AKT-, mitogen activated protein kinase (MAPK)/extracellular signal-regulated protein kinase (ERK) kinase (MEK)-ERK-dependent neurite re-growth. Our results further reveal a cross-talk between pathways involving PKC and ERK1/2 in regulating neurite re-growth and cell migration. We conclude that temporal regulation of cell migration and neurite outgrowth by SH2B1β contributes to the enhanced regeneration of differentiated PC12 cells.

Hydrogen sulfide (H(2)S) has been proposed as a novel neuromodulator and neuroprotective agent. Cobalt chloride (CoCl(2)) is a well-known hypoxia mimetic agent. We have demonstrated that H(2)S protects against CoCl(2)-induced injuries in PC12 cells. However, whether the members of mitogen-activated protein kinases (MAPK), in particular, extracellular signal-regulated kinase1/2(ERK1/2) and p38MAPK are involved in the neuroprotection of H(2)S against chemical hypoxia-induced injuries of PC12 cells is not understood. We observed that CoCl(2) induced expression of transcriptional factor hypoxia-inducible factor-1 alpha (HIF-1α), decreased cystathionine-β synthase (CBS, a synthase of H(2)S) expression, and increased generation of reactive oxygen species (ROS), leading to injuries of the cells, evidenced by decrease in cell viability, dissipation of mitochondrial membrane potential (MMP) , caspase-3 activation and apoptosis, which were attenuated by pretreatment with NaHS (a donor of H(2)S) or N-acetyl-L cystein (NAC), a ROS scavenger. CoCl(2) rapidly activated ERK1/2, p38MAPK and C-Jun N-terminal kinase (JNK). Inhibition of ERK1/2 or p38MAPK or JNK with kinase inhibitors (U0126 or SB203580 or SP600125, respectively) or genetic silencing of ERK1/2 or p38MAPK by RNAi (Si-ERK1/2 or Si-p38MAPK) significantly prevented CoCl(2)-induced injuries. Pretreatment with NaHS or NAC inhibited not only CoCl(2)-induced ROS production, but also phosphorylation of ERK1/2 and p38MAPK. Thus, we demonstrated that a concurrent activation of ERK1/2, p38MAPK and JNK participates in CoCl(2)-induced injuries and that H(2)S protects PC12 cells against chemical hypoxia-induced injuries by inhibition of ROS-activated ERK1/2 and p38MAPK pathways. Our results suggest that inhibitors of ERK1/2, p38MAPK and JNK or antioxidants may be useful for preventing and treating hypoxia-induced neuronal injury.

The development of cardiac hypertrophy in response to increased hemodynamic load and neurohormonal stress is initially a compensatory response that may eventually lead to ventricular dilation and heart failure. Regulator of G protein signaling 5 (Rgs5) is a negative regulator of G protein-mediated signaling by inactivating Galphaq and Galphai, which mediate actions of most known vasoconstrictors. Previous studies have demonstrated that Rgs5 expresses among various cell types within mature heart and showed high levels of Rgs5 mRNA in monkey and human heart tissue by Northern blot analysis. However, the critical role of Rgs5 on cardiac remodeling remains unclear. To specifically determine the role of Rgs5 in pathological cardiac remodeling, we used transgenic mice with cardiac-specific overexpression of human Rgs5 gene and Rgs5-/- mice. Our results demonstrated that the transgenic mice were resistant to cardiac hypertrophy and fibrosis through inhibition of MEK-ERK1/2 signaling, whereas the Rgs5-/- mice displayed the opposite phenotype in response to pressure overload. These studies indicate that Rgs5 protein is a crucial component of the signaling pathway involved in cardiac remodeling and heart failure.

BACKGROUND AND PURPOSE:

Atherosclerosis is a chronic inflammatory disease, in which 'vulnerable plaques' have been recognized as the underlying risk factor for coronary disease. Regulator of G-protein signalling (RGS) 5 controls endothelial cell function and inflammation. In this study, we explored the effect of RGS5 on atherosclerosis and the potential underlying mechanisms.

EXPERIMENTAL APPROACH:

RGS5(-/-) apolipoprotein E (ApoE)(-/-) and ApoE(-/-) littermates were fed a high-fat diet for 28 weeks. Total aorta surface and lipid accumulation were measured by Oil Red O staining and haematoxylin-eosin staining was used to analyse the morphology of atherosclerotic lesions. Inflammatory cell infiltration and general inflammatory mediators were examined by immunofluorescence staining. Apoptotic endothelial cells and macrophages were assayed with TUNEL. Expression of RGS5 and adhesion molecules, and ERK1/2 phosphorylation were evaluated by co-staining with CD31. Expression of mRNA and protein were determined by quantitative real-time PCR and Western blotting respectively.

KEY RESULTS:

Atherosclerotic phenotypes were significantly accelerated in RGS5(-/-) ApoE(-/-) mice, as indicated by increased inflammatory mediator expression and apoptosis of endothelial cells and macrophages. RGS5 deficiency enhanced instability of vulnerable plaques by increasing infiltration of macrophages in parallel with the accumulation of lipids, and decreased smooth muscle cell and collagen content. Mechanistically, increased activation of NF-κB and MAPK/ERK 1/2 could be responsible for the accelerated development of atherosclerosis in RGS5-deficient mice.

CONCLUSIONS AND IMPLICATIONS:

RGS5 deletion accelerated development of atherosclerosis and decreased the stability of atherosclerotic plaques partly through activating NF-κB and the MEK-ERK1/2 signalling pathways.

© 2014 The British Pharmacological Society.

OBJECTIVE:

To investigate whether lipoxin A4 (LXA4) increases expression of heme oxygenase-1(HO-1) in cardiomyocytes, whether LXA4-induced HO-1 protects cardiomyocytes against hypoxia/reoxygenation (H/R) injury, and what are the mechanisms involved in the LXA4-induced HO-1 induction.

METHODS:

Rat cardiomyocytes were exposed to H/R injury with or without preincubation with LXA4 or HO-1 inhibitor ZnPP-IX or various signal molecule inhibitors. Expressions of HO-1 protein and mRNA were analyzed by using Western blot and RT-PCR respectively. Activity of nuclear factor E2-related factor 2 (Nrf2) binding to the HO-1 E1 enhancer was assessed by chromatin immunoprecipitation. Nrf2 binding to the HO-1 antioxidant responsive element (ARE) were measured by using electrophoretic mobility shift assay.

RESULTS:

Pretreatment of the cells undergoing H/R lesion with LXA4 significantly reduced the lactate dehydrogenase and creatine kinase productions, increased the cell viability, and increased the expressions of HO-1 protein and mRNA and HO-1 promoter activity. HO-1 inhibition abolished the protective role of LXA4 on the cells undergoing H/R lesion. LXA4 increased p38 mitogen-activated protein kinase (p38 MAPK) activation, nuclear translocation of Nrf2, Nrf2 binding to the HO-1 ARE and E1 enhancer in cardiomyocytes with or without H/R exposure.

CONCLUSION:

The protection role of LXA4 against H/R injury of cardiomyocytes is related to upregulation of HO-1, via activation of p38 MAPK pathway and nuclear translocation of Nrf2 and Nrf2 binding to the HO-1 ARE and E1 enhancer, but not via activation of phosphatidyinositol-3-kinase or extracellular signal-regulated kinase pathway.

BACKGROUND:

Hepatocellular carcinoma (HCC) usually has a dismal prognosis because of its limited response to current pharmacotherapy and high metastatic rate. Sulfated oligosaccharide has been confirmed as having potent antitumor activities against solid tumors. Here, we explored the preclinical effects and molecular mechanisms of isomalto oligosaccharide sulfate (IMOS), another novel sulfated oligosaccharide, in HCC cell lines and a xenograft model.

METHODS:

The effects of IMOS on HCC proliferation, apoptosis, adhesion, migration, and invasiveness in vitro were assessed by cell counting, flow cytometry, adhesion, wound healing, and transwell assays, respectively. The roles of IMOS on HCC growth and metastasis in xenograft models were evaluated by tumor volumes and fluorescent signals. Total and phosphorylated protein levels of AKT, ERK, and JNK as well as total levels of c-MET were detected by Western blotting. IMOS-regulated genes were screened by quantitative reverse-transcription PCR (qRT-PCR) array in HCCLM3-red fluorescent protein (RFP) xenograft tissues and then confirmed by qRT-PCR in HepG2 and Hep3B cells.

RESULTS:

IMOS markedly inhibited cell proliferation and induced cell apoptosis of HCCLM3, HepG2, and Bel-7402 cells and also significantly suppressed cell adhesion, migration, and invasion of HCCLM3 in vitro. At doses of 60 and 90 mg/kg/d, IMOS displayed robust inhibitory effects on HCC growth and metastasis without obvious side effects in vivo. The levels of pERK, tERK, and pJNK as well as c-MET were significantly down-regulated after treatment with 16 mg/mL IMOS. No obvious changes were found in the levels of pAkt, tAkt, and tJNK. Ten differentially expressed genes were screened from HCCLM3-RFP xenograft tissues after treatment with IMOS at a dose of 90 mg/kg/d. Similar gene expression profiles were confirmed in HepG2 and Hep3B cells after treatment with 16 mg/mL IMOS.

CONCLUSIONS:

IMOS is a potential anti-HCC candidate through inhibition of ERK and JNK signaling independent of p53 and worth studying further in patients with HCC, especially at advanced stages.

Previous studies have demonstrated that tumor necrosis factor-alpha (TNF-α) in the red nucleus (RN) plays a facilitated role in the development of neuropathic pain. Here, we further investigated the expression changes and roles of the downstream signaling molecules of the red nucleus TNF-α, including nuclear factor-kappa B (NF-κB), extracellular signal-regulated kinase (ERK), p38 mitogen-activated protein kinase (MAPK) and c-Jun N-terminal kinase (JNK), in the initiation and maintenance of neuropathic pain induced by spared nerve injury (SNI). Immunohistochemistry demonstrated that increased expressions of NF-κB, phospho-ERK (p-ERK) and p-p38 MAPK were observed in the RN contralateral (but not ipsilateral) to the nerve injury side at 3 days after SNI compared with sham-operated and normal rats, the up-regulations of NF-κB and p-ERK but not p-p38 MAPK remained at high levels till 14 days later. An elevated expression of p-JNK occurred at 14 days (but not 3 and 7 days) after SNI, which was later than those of NF-κB, p-ERK and p-p38 MAPK. The up-regulations of NF-κB, p-ERK, p-p38 MAPK and p-JNK all could be abolished by microinjection of anti-TNF-α antibody into the RN of rats with SNI. Microinjection of NF-κB inhibitor PDTC, ERK inhibitor PD98059, p38 MAPK inhibitor SB203580 but not JNK inhibitor SP600125 into the RN contralateral to the nerve injury side at 3 days postinjury significantly alleviated SNI-induced mechanical allodynia. In addition, microinjection of PDTC, PD98059 and SP600125 but not SB203580 into the RN at 14 days postinjury significantly alleviated SNI-induced mechanical allodynia. These results suggest that the red nucleus TNF-α produces the algesic effect through activating NF-κB, ERK and p38 MAPK in the early initiation stage but relying on the activation of NF-κB, ERK and JNK in the later maintenance stage of SNI-induced neuropathic pain.

Previous studies have demonstrated that protein tyrosine phosphatase 1B (PTP1B) can promote tumor progression in breast cancer, colon cancer and prostate cancer. Additionally, PTP1B acts as a tumor suppressor in other cancers, such as esophageal cancer and lymphoma. These findings suggest that PTP1B functions as a double-facet molecule in tumors, and the role of PTP1B in non-small cell lung cancer (NSCLC) is unknown. The present study demonstrates that the expression of PTP1B in NSCLC tissue is significantly higher than its expression in benign lung disease and is associated with the stage and overall survival (OS) of NSCLC patients. In vitro studies have demonstrated that PTP1B promotes the proliferation and metastasis of NSCLC cells by reducing the expression of p-src (Tyr527), which activates src and ERK1/2. This study provides the first exploration of the role of PTP1B in the proliferation and metastasis of NSCLC and subsequently elucidates the role of PTP1B in cancer. Our study uncovered that PTP1B can promote NSCLC proliferation and metastasis by activating src and subsequently ERK1/2 and provides a theoretical basis for future applications of PTP1B inhibitors in the treatment of NSCLC.

The crude powder of the fruit of Arctium lappa L. (ALF) has previously been reported to attenuate experimental colitis in mice. But, its main effective ingredient and underlying mechanisms remain to be identified. In this study, ALF was extracted with ethanol, and then successively fractionated into petroleum ether, ethyl acetate, n-butanol and water fraction. Experimental colitis was induced by dextran sulfate sodium (DSS) in mice. Among the four fractions of ALF, the ethyl acetate fraction showed the most significant inhibition of DSS-induced colitis in mice. The comparative studies of arctigenin and arctiin (the two main ingredients of ethyl acetate fraction) indicated that arctigenin rather than arctiin could reduce the loss of body weight, disease activity index and histological damage in the colon. Arctigenin markedly recovered the loss of intestinal epithelial cells (E-cadherin-positive cells) and decreased the infiltration of neutrophils (MPO-positive cells) and macrophages (CD68-positive cells). Arctigenin could down-regulate the expressions of TNF-α, IL-6, MIP-2, MCP-1, MAdCAM-1, ICAM-1 and VCAM-1 at both protein and mRNA levels in colonic tissues. Also, it markedly decreased the MDA level, but increased SOD activity and the GSH level. Of note, the efficacy of arctigenin was comparable or even superior to that of the positive control mesalazine. Moreover, it significantly suppressed the phosphorylation of MAPKs and the activation of NF-κB, including phosphorylation of IκBα and p65, p65 translocation and DNA binding activity. In conclusion, arctigenin but not arctiin is the main active ingredient of ALF for attenuating colitis via down-regulating the activation of MAPK and NF-κB pathways.

Gouty arthritis is an inflammatory disease that is caused by an accumulation of monosodium urate (MSU) crystals in the joints. MSU is capable of activating the nucleotide-binding oligomerization domain-like receptor pyrin domain containing 3 (NLRP3) inflammasome, leading to interleukin-1β (IL-1β) secretion. Reactive oxygen species (ROS) are major mediators of the NLRP3/IL-1β interaction. Although nuclear factor E2-related factor 2 (Nrf2) is recognized as a transcription factor that is involved in the response to oxidative stress, the effect of MSU on Nrf2 and on Nrf2-mediated antioxidant enzymes remains unclear. The treatment of THP-1 monocytes using phorbol 12-myristate 13-acetate (PMA) was shown to initiate inflammatory responses. Here, we showed that THP-1 cells, following treatment with MSU crystals, significantly increased IL-1β release, NLRP3 inflammasome activation and ROS production. MSU also promoted the nuclear translocation of Nrf2 and activated lysosomal destabilization. Moreover, the levels of heme oxygenase-1 (HO-1) in gene and protein expressions were upregulated by MSU. MSU-induced IL-1β secretion and NLRP3 inflammasome activation were inhibited by the knockdown of Nrf2 and via the HO-1 inhibitor zinc (II) protoporphyrin IX (ZnPP). In addition, HO-1 inhibition increased the level of superoxide anion production and the consumption of glutathione. These findings suggest that Nrf2 and HO-1 mediate redox homeostasis and interact with pro-inflammatory factors in MSU-challenged THP-1 cells, thereby providing new insight into how MSU-induced gouty inflammation is mediated by specific mechanisms that are involved in the Nrf2/Ho-1 antioxidant signaling pathway.Cellular & Molecular Immunology advance online publication, 11 August 2014; doi:10.1038/cmi.2014.65.

Tenuifoliside A (TFSA) is a bioactive oligosaccharide ester component of Polygala tenuifolia Wild, a traditional Chinese medicine which was used to manage mental disorders effectively. The neuroprotective and anti-apoptotic effects of TFSA have been demonstrated in our previous studies. The present work was designed to study the molecular mechanism of TFSA on promoting the viability of rat glioma cells C6. We exposed C6 cells to TFSA (or combined with ERK, PI3K and TrkB inhibitors) to examine the effects of TFSA on the cell viability and the expression and phosphorylation of key proteins in the ERK and PI3K signaling pathway. TFSA increased levels of phospho-ERK and phospho-Akt, enhanced release of BDNF, which were blocked by ERK and PI3K inhibitors, respectively (U0126 and LY294002). Moreover, the TFSA caused the enhanced phosphorylation of cyclic AMP response element binding protein (CREB) at Ser133 site, the effect was revoked by U0126, LY294002 and K252a. Furthermore, when C6 cells were pretreated with K252a, a TrkB antagonist, known to significantly inhibit the activity of brain-derived neurotrophic factor (BDNF), blocked the levels of phospho-ERK, phospho-Akt and phosphor-CREB. Taking these results together, we suggested the neuroprotection of TFSA might be mediated through BDNF/TrkB-ERK/PI3K-CREB signaling pathway in C6 glioma cells.

Sensitization and activation of trigeminal nociceptors is implicated in prevalent and debilitating orofacial pain conditions including temporomandibular joint (TMJ) disorders. Orexins are excitatory neuropeptides that function to regulate many physiological processes and are reported to modulate nociception. To determine the role of orexins in an inflammatory model of trigeminal activation, the effects of a dual orexin receptor antagonist (DORA-12) on levels of proteins that promote peripheral and central sensitization and changes in nocifensive responses were investigated. In adult male Sprague-Dawley rats, mRNA for orexin receptor 1 (OX₁R) and receptor 2 (OX₂R) were detected in trigeminal ganglia and spinal trigeminal nucleus (STN). OX₁R immunoreactivity was localized primarily in neuronal cell bodies in the V3 region of the ganglion and in laminas I-II of the STN. Animals injected bilaterally with complete Freund's adjuvant (CFA) in the TMJ capsule exhibited increased expression of P-p38, P-ERK, and lba1 in trigeminal ganglia and P-ERK and lba1 in the STN at 2 days post injection. However, levels of each of these proteins in rats receiving daily oral DORA-12 were inhibited to near basal levels. Similarly, administration of DORA-12 on days 3 and 4 post CFA injection in the TMJ effectively inhibited the prolonged stimulated expression of protein kinase A, NFkB, and Iba1 in the STN on day 5 post injection. While injection of CFA mediated a nocifensive response to mechanical stimulation of the orofacial region at 2h and 3 and 5 days post injection, treatment with DORA-12 suppressed the nocifensive response on day 5. Somewhat surprisingly, nocifensive responses were again observed on day 10 post CFA stimulation in the absence of daily DORA-12 administration. Our results provide evidence that DORA-12 can inhibit CFA-induced stimulation of trigeminal sensory neurons by inhibiting expression of proteins associated with sensitization of peripheral and central neurons and nociception.

The mechanism of blue light-induced retinal ganglion cell (RGC) injury is poorly understood. In this study, we established a patented light-emitting diode-based system to study the effects of long-term blue light exposure under culture conditions on RGC-5 cells. Long-term blue light exposure significantly reduced cell viability in a time-dependent manner and induced apoptosis and necrosis in RGC-5 cells. Long-term blue light exposure marked an increase in the expression of Bax and active Caspase-3 (p17), which was accompanied by Bcl-2 down-regulation, and displayed features of the mitochondria-dependent apoptosis pathway. Blue light exposure also increased the generation of reactive oxygen species (ROS), and was a strong inducer of ROS-sensitive protein nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) expression. Moreover, blue light exposure constitutively activated p38 mitogen-activated protein kinases and c-Jun NH2-terminal kinase (JNK), as well as induced the phosphorylation of extracellular signal-regulated kinase in the early phase, in blue light-exposed RGC-5 cells. The protein expression of c-jun and c-fos was further enhanced after RGC-5 cells were exposed to blue light. Taken together, these findings indicated that blue light induced RGC-5 cell line death in dependence upon exposure duration. The potential mechanisms for this phenomenon might be via activated mitochondria-dependent apoptosis, increased ROS production and protein expressions of Nrf2 and HO-1, and activated JNK/p38 MAPK signaling pathways.

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.

Angiogenesis is a process that forms new blood capillaries from existing vessels, which is of great physiological and pathological significance. Although recent studies provide evidence that cuprous oxide nanoparticles (CO-NPs) may have biomedical potential, the mechanisms of CO-NPs in angiogenesis have not been investigated to date. We have studied the anti-angiogenic properties of CO-NPs on primary human umbilical vein endothelial cells (HUVECs). We found that CO-NPs were able to induce cell morphology changes and suppress cell proliferation, migration and tube formation in vitro and in vivo dose dependently. Furthermore, CO-NPs could induce cell apoptosis both at the early and late apoptotic stage and induce cell cycle arrest at S phase in a dose dependent manner. As signalling via the vascular endothelial growth factor receptor-2 (VEGFR2) is critical for angiogenic responses, we further explored the expression of VEGFR2 after the treatment of CO-NPs. They were found to inhibit VEGFR2 expression dose and time dependently both at the protein and mRNA level while had no effect on VEGF and VEGFR1 expression. Together, we report for the first time that CO-NPs can act as an anti-angiogenic agent by suppressing VEGFR2 expression, which may be a potential nanomedicine for angiogenesis therapy.

The c-Jun N-terminal kinase (JNK) is well known to play an important role in cell death signaling of the p75 neurotrophin receptor. However, little has been studied about a role of JNK in the signaling pathways of the tropomyosin-related kinase A (TrkA) neurotrophin receptor. In this study, we investigated JNK inhibitor SP600125-controlled TrkA-dependent targets by proteomic analysis to better understand an involvement of JNK in TrkA-mediated signaling pathways. PDQuest image analysis and protein identification results showed that hnRNP C1/C2, α-tubulin, β-tubulin homolog, actin homolog, and eIF-5A-1 protein spots were upregulated by ectopic expression of TrkA, whereas α-enolase, peroxiredoxin-6, PROS-27, HSP70, PP1-gamma, and PDH E1-alpha were downregulated by TrkA, and these TrkA-dependent upregulation and downregulation were significantly suppressed by SP600125. Notably, TrkA largely affected certain PTM(s) but not total protein amounts of the SP600125-controlled TrkA-dependent targets. Moreover, SP600125 strongly suppressed TrkA-mediated tyrosine phosphorylation signaling pathways as well as JNK signaling, indicating that SP600125 could function as a TrkA inhibitor. Taken together, our results suggest that TrkA could play an important role in the cytoskeleton, cell death, cellular processing, and glucose metabolism through activation or inactivation of the SP600125-controlled TrkA-dependent targets.

Hydrolyzed fish collagen (HFC) has recently attracted considerable attention because of its outstanding bioactivity. However, few studies have been performed to determine the biological effects of HFC on bone marrow mesenchymal stem cells (BMSCs), which are often used in regenerative medicine. In this study, the molecular weight, amino acid composition, and contact angle of HFC were measured. The influence of HFC on cell viability and the multidirectional differentiation of BMSCs into osteogenic, endothelial, adipogenic, chondrogenic, and neural lineages were also assessed. Furthermore, the mechanism by which HFC promotes osteogenesis was investigated at the protein level. The molecular weight of HFC ranged from 700 to 1300 Da, the contact angle of HFC was approximately 26°, and HFC was found to be composed of various amino acids, including glycine, proline, and hydroxyproline. At a concentration of 0.2 mg/mL, HFC promoted cell viability, and significantly up-regulated the expression of osteogenic markers (RUNX2, ALP, OPN, and OCN), as well as endothelial markers (CD31, VE-cadherin, and VEGFR2). Western blot results indicated that treatment of BMSCs with 0.2 mg/mL HFC could activate the MAPK/ERK signaling pathway and then increase the protein level of RUNX2, while treatment with PD98059, a specific inhibitor of ERK1/2, could significantly inhibit the expression of P-ERK and RUNX2. Interestingly, real-time PCR demonstrated that HFC inhibited the expression of adipogenic markers (LPL and ADFP) and chondrogenic markers (aggrecan and COLII), whereas it had no effect on neural differentiation markers (MAP2 and β3-tubulin). In summary, this study suggests that without the use of any additional inducing reagent, HFC has the potential to actively promote osteogenic and endothelial differentiation because of its high hydrophilicity and the optimal extracellular microenvironment supplied by its amino acids. This research also revealed that HFC inhibited adipogenic and chondrogenic differentiation, but it had no influence on the neural differentiation of rat bone marrow mesenchymal stem cells (rBMSCs).

Multiple studies have indicated that selective cyclooxygenase-2 (COX-2) inhibitors possess clinically chemopreventive and preclinically anticancer activities. Their long-term use, however, may be limited by the cardiovascular toxicity. This study tried to investigate whether an apple oligogalactan (AOG) could enhance the growth inhibitory effect of celecoxib on colorectal cancer. Caco-2 and HT-29 cell lines were exposed to different concentrations of AOG (0-1 g/L), celecoxib (0-25 μmol/L), and their combination. COX-2 levels were assessed by reverse transcription PCR and Western blot. COX-2 activity was evaluated by measuring prostaglandin E2 concentration. A colitis-associated colorectal cancer (CACC) mouse model was used to determine the effect of the combination in vivo. AOG (0.1-0.5 g/L) could potentiate the inhibitory effect of physiologic doses of celecoxib (5 μmol/L) on cell growth and decrease COX-2 expressions both at RNA and protein levels. In vivo, the combination (2.5% AOG plus 0.04% celecoxib, w/w) prevented against CACC in mice effectively. Our data indicate that AOG could potentiate the growth inhibitory effect of celecoxib on colorectal cancer both in vitro and in vivo through influencing the expression and function of COX-2 and phosphorylation of MAPKs, which suggests a new possible combinatorial strategy in colorectal cancer therapy.

This study was conducted to demonstrate myocardial protective effects and possible underlying mechanisms of vitexin on myocardial ischemia/reperfusion (I/R) injury in rats. Occluding the anterior descending artery for 30 min and restoring blood perfusion for 60 min in rat established a model of myocardial I/R. The elevation of the ST segment of Electrocardiograph (ECG) was observed. The infarct size of the rat heart was assessed by triphenyltetrazolium chloride staining (TTC). LDH, CK, SOD activities and MDA content were determined. An immunohistochemical analysis was applied to measure the expression of myocardial NF-κBp65 and TNF-α. ERK/phospho-ERKand c-Jun/phospho-c-Jun protein expression was examined via Western Blot. Vitexin significantly reduced the elevation of the ST segment of ECG and myocardial infarct size. LDH and CK activities and MDA content were attenuated in serum, while SOD activity was markedly enhanced. Vitexin significantly attenuated I/R-induced increases of myocardial NF-κB and TNF-α. Moreover, Western Blot analysis presented that vitexin markedly enhanced the expression of phospho-ERK and weakened the expression of phospho-c-Jun compared to I/R group. The significant protective effect against myocardial ischemical/reperfusion injury in rat, which is exhibited by vitexin, may be related to its antioxidative and anti-inflammatory effects by regulating inflammatory cytokines and the MAPK pathway.

Previous studies have demonstrated that tumor necrosis factor-alpha (TNF-α) in the red nucleus (RN) plays facilitated roles in the development of abnormal pain. Here, the roles of nuclear factor-kappa B (NF-κB), extracellular signal-regulated kinase (ERK), p38 mitogen-activated protein kinase (MAPK) and c-Jun N-terminal kinase (JNK) in TNF-α-evoked mechanical allodynia were investigated. Repeated microinjection of recombinant rat TNF-α (20 ng daily for 3 days) into the unilateral RN of normal rats induced a significant mechanical allodynia in the contralateral but not ipsilateral hind paw at the fifth day and disappeared 24h later. Re-injection of a single bolus of 20 ng TNF-α into the same RN reproduced this mechanical allodynia within 30 min, which was used as a pain model for further experiments. Immunohistochemistry demonstrated that NF-κB, phospho-ERK (p-ERK) and p-p38 MAPK in the RN were significantly up-regulated at 1h after TNF-α microinjection, the up-regulations of NF-κB and p-ERK but not p-p38 MAPK remained at high levels till 4h later. A significant up-regulation of p-JNK occurred at 4h (but not 1h) after TNF-α microinjection, which was later than those of NF-κB, p-ERK and p-p38 MAPK. Pre-treatment with NF-κB inhibitor PDTC, ERK inhibitor PD98059 or p38 MAPK inhibitor SB203580 at 30 min before TNF-α microinjected into the RN completely prevented TNF-α-evoked mechanical allodynia. Pre-treatment with JNK inhibitor SP600125 did not prevent but reversed TNF-α-evoked mechanical allodynia during the subsequent detection time. Post-treatment with PDTC, PD98059 or SP600125 (but not SB203580) at 4h after TNF-α microinjected into the RN significantly reversed TNF-α-evoked mechanical allodynia. These results further prove that TNF-α in the RN plays a crucial role in the development of abnormal pain, and the algesic effect of TNF-α is initiated through activating NF-κB, ERK and p38 MAPK. The later maintenance of TNF-α-evoked mechanical allodynia mainly relies on the activation of NF-κB, ERK and JNK, but not p38 MAPK.

Microglia-involved neuroinflammation is thought to promote brain damage in various neurodegenerative disorders. Therefore, novel therapeutics suppressing microglia over-activation could prove useful for neuroprotection in inflammation-mediated neurodegenerative diseases. DSF-52 is a novel sesquiterpene dimer compound isolated from medical plant Artemisia argyi by our group. In this study, we investigated whether DSF-52 inhibited the neuroinflammatory responses in lipopolysaccharide (LPS)-activated microglia. Our findings showed that DSF-52 inhibited the production of nitric oxide (NO), prostaglandin E2 (PGE2), tumor necrosis factor-α (TNF-α), as well as mRNA expression of inducible nitric oxide synthase (iNOS), cyclooxygenase 2 (COX-2), interleukin-1β (IL-1β), granulocyte-macrophage colony-stimulating factor (GM-CSF) and macrophage inflammatory protein-1α (MIP-1α) in LPS-activated BV-2 microglia. Moreover, DSF-52 markedly up-regulated mRNA levels of anti-inflammatory cytokine IL-10. Mechanism study indicated that DSF-52 suppressed Akt/IκB/NF-κB inflammation pathway against LPS treatment. Also, DSF-52 down-regulated the phosphorylation levels of JNK and p38 MAPKs, but not ERK. Furthermore, DSF-52 blocked Jak2/Stat3 dependent inflammation pathway through inhibiting Jak2 and Stat3 phosphorylation, as well as Stat3 nuclear translocation. We concluded that the inhibitory ability of DSF-52 on microglia-mediated neuroinflammation may offer a novel neuroprotective modality and could be potentially useful in inflammation-mediated neurodegenerative diseases.

The neuroprotective effect and mechanism of the flavonoid-rich extract (FRE) from Rosa laevigata Michx fruit on cerebral ischemia-reperfusion (I/R) injury were investigated. The contents of flavonoids, saponins and tannin were determined, and ten chemicals including chlorogenic acid, 4-hydroxy-3-methoxybenzoic acid, apigenin, luteolin, kaempferol, querce-tin, kaempferide-3-O-glucoside, quercetin-3-rhamnoside, rutin and isorhamnetin-3-O-β-rutinoside from the crude extract were separated. Oral administration of FRE obviously improved the survival rate and prevented I/R-induced disability and histological damage. Further works showed that the natural product had excellent antioxidant activity, significantly decreased DNA fragmentation, up-regulated the expression of Bcl-2, and down-regulated the expressions of p53, Apaf1, Fas, FasL, Bax, Bid, cytochrome C and active Caspase-3, -9 and -8. Moreover, the FRE decreased the expressions of NF-κB, iNOS, MMP-9, COX-2, TNF-α, IL-1β, IL-4, IL-6, and down-regulated the levels of p-JNK, p-ERK and p-p38 in MAPK pathways. Therefore, the flavonoid-rich extract from R. laevigata Michx fruit has the potential actions for treatment of ischemic stroke due to its anti-oxidant, anti-apoptosis and anti-inflammatory properties.

Porous β-CaSiO3/β-Ca3(PO4)2 (β-CS/β-TCP) composite scaffolds have been previously shown to promote bone formation in vivo. However, the mechanisms underlying such beneficial effects remain unclear. In this study, we recreated an extracellular environment using the extracts of β-CS/β-TCP composites developed in our previous in vivo study, and investigated the effects of the extracts on osteogenic differentiation of rat bone marrow-derived mesenchymal stem cells (rBMSCs) and its related mechanisms. The angiogenic potential of the extracts was also evaluated using human umbilical vein endothelial cells (HUVECs). In the absence of osteogenic supplements, the osteogenic differentiation of rBMSCs was detected by alkaline phosphatase (ALP) activity assay and the messenger RNA expression of a panel of osteoblast markers. The results showed that the soluble ions of porous β-CS/β-TCP composites were capable of promoting cell viability, directly inducing cell differentiation. The increase in phosphorylation of AMP-activated protein kinase (AMPK) and ERK1/2 were observed in rBMSCs cultured in β-CS/β-TCP composite extracts. The ALP expression, calcium deposition, and ERK1/2 phosphorylation of rBMSCs, which was promoted by ions released from β-CS/β-TCP composites, were blocked by an AMPK inhibitor, Compound C. These results indicate that bioactive ions extracted from β-CS/β-TCP composites could stimulate the osteogenic differentiation of rBMSCs via the AMPK-Erk1/2 pathway. Interestingly, the secretion of vascular endothelial growth factor and the viability of HUVECs were shown to be enhanced in the presence of extracts from the β-CS/β-TCP composite scaffolds. Our findings suggest that 50 or 80% wt. CS could promote bone regeneration by stimulating osteogenesis and angiogenesis.

Urocortin (UCN1) is a member of corticotrophin-releasing factor (CRF) family, which has been proven to participate in inflammation. Previous work showed that dihydrotestosterone (DHT) could promote the inflammatory process. Little is known about the effect of DHT on UCN1 expression. The aim of our study is to investigate the effects and underlying mechanisms of DHT on endothelial UCN1 expression in the absence and presence of induced inflammation. Therefore, we tested the alterations of endothelial UCN1 expression treated with DHT in the presence or absence of lipopolysaccharide (LPS). Our data showed that DHT alone decreased UCN1 levels, which were attenuated in the presence of the androgen receptor (AR) antagonist flutamide. Conversely, in the presence of LPS, DHT augmented the LPS-induced increase in UCN1 expression, which was, interestingly, not affected by flutamide. When cells were treated with DHT alone, AR was upregulated and translocated into the nuclei, which might repress UCN1 expression via a potential androgen-responsive element found in human CRF family promoter. In the presence of LPS, DHT did not influence AR expression and location while it increased toll-like receptor 4 expression and activation, which was not altered by flutamide. DHT enhanced LPS-induced p38MAPK, ERK1/2, and nuclear factor κB pathway activation, which may contribute to the elevated expression of UCN1. These data suggest that DHT differentially influences UCN1 levels under normal and inflammatory conditions in human umbilical vein endothelial cells, which involves AR-dependent and -independent mechanisms respectively.

An herb-derived phenolic compound, 4-hydroxybenzyl alcohol (4-HBA), exhibits beneficial effects in cerebral ischemic injury. However, the molecular mechanisms underlying this observation remain unclear. Here we used an in vitro ischemic model of oxygen-glucose deprivation followed by reperfusion (OGD/R) and an in vivo ischemic model of middle cerebral artery occlusion to investigate the relevant neuroprotective mechanisms. We demonstrated that 4-HBA reduced the neuronal injury, LDH release, and up-regulation of 8-hydroxydeoxyguanosine (8-OHdG) induced by OGD/R. Furthermore, 4-HBA reduced the cerebral infarct size and improved the behavioral parameters after cerebral ischemia. These neuroprotective effects may be conferred by the 4-HBA mediated upregulation of the transcription factor nuclear factor E2-related factor 2 (Nrf2), peroxiredoxin 6 (Prdx6) and protein disulfide isomerase (PDI) by the use of 4-HBA. Interestingly, LY294002, a phosphatidylinositol 3-kinase (PI3K) inhibitor, blocked the increase in phosphorylation of Akt and abolished the neuroprotection associated with 4-HBA. Our results suggested that 4-HBA protects neurons against cerebral ischemic injury, and this neuroprotection may occur through upregulation of Nrf2, Prdx6, and PDI expression via the PI3K/Akt pathway.

The blood-retinal barrier (BRB) is critical for maintaining retina homeostasis and low permeability. In this study, we evaluated the effects of electromagnetic pulse (EMP) exposure on the permeability of BRB, alterations of tight junction (TJ) proteins of BRB and if any, involvement of mitogen-activated protein kinase (MAPK) pathway. Male Sprague-Dawley (SD) rats and RF/6A cells which were pretreated with or without MAPKs inhibitors were sham exposed or exposed to EMP at 200kV/m for 200 pulses. The alteration of BRB permeability was examined through fluorescence microscope and quantitatively assessed using Evans blue (EB) and endogenous albumin as tracers. The expressions of TJ proteins and some signaling molecules of MAPK pathway were measured by Western blots. The observations were that EMP exposure resulted in increased BRB permeability concurrent with the decreased expressions of occludin and claudin-5, which were correlated with the increased expressions of phospho-p38, phospho-JNK and phospho-ERK and could be blocked when pretreated with p38 MAPK inhibitor. Thus, the results suggested that the alterations of occludin and claudin-5 may play an important role in the disruption of TJs, which may lead to the transient breakdown of BRB after EMP exposure with the involvement of p38 MAPK pathway through phosphorylation of signaling molecules.

Incidence of hepatocellular carcinoma (HCC) is dramatically increasing and is the third cause of cancer death worldwide. One key approach to control HCC is chemoprevention by naturally occurring agents. This study aims at investigating the antitumor effect of oleanolic acid (OA) and the molecular mechanisms. BALB/c mice were injected subcutaneously with HepG2 cells to establish transplanted tumors. Apoptosis and cell cycle arrest-related markers and signaling cascades were determined by western blot, immunofluorescence, reverse transcriptase-polymerase chain reaction and flow cytometric analysis. OA exhibited inhibitory effect on HCC through induction of apoptosis and cell cycle arrest both in transplanted tumors and in HepG2 cells. OA induced apoptosis through mitochondrial pathway, evidenced by inhibition of Akt/mammalian target of rapamycin pathway, mitochondrial dysfunction, transient increase of adenosine triphosphate, increase of Bax/Bcl-2 ratio, increased release of cytochrome c and activation of caspase/poly (ADP-ribose) polymerase. Activation of mitochondrial apoptotic pathway may be due to reactive oxygen species generated by mitochondrial fatty acid oxidation, resulted from enhancement of lipolysis regulated by cyclic adenosine 3',5'-monophosphate response element-binding protein-hormone-sensitive lipase/peroxisome proliferator-activated receptor γ signaling. OA induced G2/M cell cycle arrest through p21-mediated downregulation of cyclin B1/cdc2. Cyclooxygenase-2 (COX-2) and p53 were involved in OA-exerted effect, and extracellular signal-regulated kinase-p53 signaling played a central role in OA-activated cascades responsible for apoptosis and cell cycle arrest. OA demonstrated significant antitumor activities in HCC in vivo and in vitro models. These data provide new insights into the mechanisms underlying the antitumor effect of OA.

Interferon regulatory factor (IRF) 3, a member of the highly conserved IRF family transcription factors, plays a pivotal role in innate immune response, apoptosis, and oncogenesis. Recent studies have implicated IRF3 in a wide range of host defense. However, whether IRF3 induces defensive responses to hypertrophic stresses such as biomechanical stress and neurohumoral factors remains unclear. Herein, we employed an IRF3-deficient mouse model, cardiac-specific IRF3-overexpression mouse model and isolated cardiomyocytes to investigate the role of IRF3 in cardiac hypertrophy induced by aortic banding (AB) or isoproterenol (ISO). The extent of cardiac hypertrophy was quantitated by echocardiography as well as by pathological and molecular analysis. Our results demonstrate that IRF3 deficiency profoundly exacerbated cardiac hypertrophy, whereas overexpression of IRF3 in the heart significantly blunted pathological cardiac remodeling induced by pressure overload. Similar results were also observed in cultured cardiomyocytes upon the treatment with ISO. Mechanistically, we discovered that IRF3 interacted with ERK2 and thereby inhibited the ERK1/2 signaling. Furthermore, inactivation of ERK1/2 by U0126 offset the IRF3-deficient-mediated hypertrophic response induced by aortic banding. Altogether, these data demonstrate that IRF3 plays a protective role in AB-induced hypertrophic response by inactivating ERK1/2 in the heart. Therefore, IRF3 could be a new target for the prevention and therapy of cardiac hypertrophy and failure.

HERV-K (human endogenous retrovirus type K) type 1-encoded Np9 is a tumor-specific biomarker, but its oncogenic role and targets in human leukemia remain elusive. We first identified Np9 as a potent viral oncogene in human leukemia. Silencing of Np9 inhibited the growth of myeloid and lymphoblastic leukemic cells, whereas expression of Np9 significantly promoted the growth of leukemia cells in vitro and in vivo. Np9 not only activated ERK, AKT and Notch1 pathways but also upregulated β-catenin essential for survival of leukemia stem cells. In human leukemia, Np9 protein level in leukemia patients was substantially higher than that in normal donors (56% vs 4.5%). Moreover, Np9 protein level was correlated with the number of leukemia stem/progenitor cells but not detected in normal CD34(+) hematopoietic stem cells. In addition, Np9-positive samples highly expressed leukemia-specific pol-env polyprotein, env and transmembrane proteins as well as viral particles. Thus, the viral oncogene Np9 is a critical molecular switch of multiple signaling pathways regulating the growth of leukemia stem/progenitor cells. These findings open a new perspective to understand the etiology of human common leukemia and provide a novel target for treating leukemia.

As a potential bioactive material, β-calcium silicate (β-CS) has attracted particular attention in the field of bone regeneration. In this study, porous β-CS/Poly-D,L-Lactide-Glycolide (PDLGA) composite scaffolds were developed with the goals of controlling the degradation rate and improving the mechanical and biological properties. The compressive strength and toughness were significantly enhanced by PDLGA modification of porous β-CS ceramic scaffolds. The effects of the ionic extract from β-CS/PDLGA composite scaffolds on osteogenic differentiation of rat bone marrow-derived mesenchymal stem cells (rBMSCs), proliferation of human umbilical vein endothelial cells (HUVECs) and the related mechanisms were investigated. It was shown that bioactive ions from β-CS/PDLGA scaffolds could enhance cell viability, alkaline phosphatase (ALP) activity, calcium mineral deposition, and mRNA expression levels of osteoblast-related genes of rBMSCs without addition of extra osteogenic reagents. The activation in AMP-activated protein kinase (AMPK), extracellular signal-related kinases (ERK) 1/2 and RUNX-2 were observed in rBMSCs cultured in the extract of β-CS/PDLGA, and these effects could be blocked by AMPK inhibitor Compound C. The extracts of β-CS/PDLGA composites stimulated HUVECs proliferation that was associated with phosphorylation of protein kinase B (Akt) and endothelial nitric oxide synthase (eNOS) as well as an increase in nitric oxide (NO) production and secretion of vascular endothelial growth factor (VEGF). The inductions were abolished by the addition of phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002. The composite scaffolds were implanted in critical sized rabbit femur defects (6 × 10 mm) for 4, 12 and 20 weeks with β-tricalcium phosphate (β-TCP) as controls. Sequential histological evaluations and radiographs revealed that β-CS/PDLGA dramatically stimulated new bone formation and angiogenesis. The biodegradation rate of the β-CS/PDLGA scaffolds was lower than that of β-TCP at each time point examined, and matched the new bone formation rates. These data suggest that β-CS/PDLGA could promote bone regeneration in vivo, which might be ascribed to the enhanced osteogenic differentiation of mesenchymal stem cells (MSCs) and increased angiogenic activity of endothelial cells (ECs).

Cyclophilin A (CypA) plays an important role in many physiology processes and its overexpression has been involved in many diseases including immune disease, viral infection, neuro-degenerative disease, and cancer. However, the actual role of CypA in the diseases is still far from clear, and a complete understanding of CypA is necessary in order to direct more specific and effective therapeutic strategies. Based on the screening of our in-house library through the isomer-specific proteolysis method, we find a CypA activator (1-(2,6-Dibenzyloxybenzoyl)-3-(9H-fluoren-9-yl)-urea), compound 1a, which can increase CypA's PPIase activity and give allosteric behavior. The binding affinity of compound 1a to CypA has been confirmed by Fortebio's Octet RED system and the increased phosphorylation of ERK in H446 cells is observed by treatment with both compound 1a and CsA. In order to further evaluate the binding mode between the activator and CypA, the allosteric binding site and allosteric mechanism of CypA are investigated by molecular dynamics (MD) simulations in combination with mutagenesis experiments. The results show that the allosteric binding site of CypA is 7Å away from its catalytic site and is composed of Cys52, His70, His54, Lys151, Thr152 and Lys155. Compound 1a binds to the allosteric site of CypA, stabilizing the active conformation of catalytic residues, and finally promotes the catalytic efficiency of CypA. We believe our finding of the CypA allosteric activator will be used as an effective chemical tool for further studies of CypA mechanisms in diseases.

Both the deregulation of microRNAs and epidermal growth factor receptor (EGFR) are emerging as important factors in non-small-cell lung cancer (NSCLC). Here, miR-133b was found to be associated with tumor stage, the extent of regional lymph node involvement, stage, visceral pleura or vessel invasion and EGFR mRNA expression in Chinese patients with NSCLC. Bioinformatic analysis and luciferase reporter assay revealed that miR-133b can interact specifically with the 3'-UTR of EGFR mRNA. Functionally, miR-133b transfection showed regulatory activity in translationally repressing EGFR mRNA. Moreover, miR-133b transfection may modulate apoptosis, invasion and sensitivity to EGFR-TKI through the EGFR signaling pathways, especially in EGFR-addicted NSCLC cells. Taken together, our findings show that miR-133b can inhibit cell growth of NSCLC through targeting EGFR and regulating its downstream signaling pathway. This finding has important implications for the development of targeted therapeutics for a number of EGFR-addicted cancers.

Cardiac hypertrophy is a response of the myocardium to increased workload and is characterised by an increase of myocardial mass and an accumulation of extracellular matrix (ECM). As an ECM protein, an integrin ligand, and an angiogenesis inhibitor, all of which are key players in cardiac hypertrophy, mindin is an attractive target for therapeutic intervention to treat or prevent cardiac hypertrophy and heart failure. In this study, we investigated the role of mindin in cardiac hypertrophy using littermate Mindin knockout (Mindin ( -/- )) and wild-type (WT) mice. Cardiac hypertrophy was induced by aortic banding (AB) or angiotensin II (Ang II) infusion in Mindin ( -/- ) and WT mice. The extent of cardiac hypertrophy was quantitated by echocardiography and by pathological and molecular analyses of heart samples. Mindin ( -/- ) mice were more susceptible to cardiac hypertrophy and fibrosis in response to AB or Ang II stimulation than wild type. Cardiac function was also markedly exacerbated during both systole and diastole in Mindin ( -/- ) mice in response to hypertrophic stimuli. Western blot assays further showed that the activation of AKT/glycogen synthase kinase 3β (GSK3β) signalling in response to hypertrophic stimuli was significantly increased in Mindin ( -/- ) mice. Moreover, blocking AKT/GSK3β signalling with a pharmacological AKT inhibitor reversed cardiac abnormalities in Mindin ( -/- ) mice. Our data show that mindin, as an intrinsic cardioprotective factor, prevents maladaptive remodelling and the transition to heart failure by blocking AKT/GSK3β signalling.

Diabetic encephalopathy is clinically characterized by acquired behavior and cognitive dysfunction but its pathogenesis is not clear. This study aimed to explore the pathogenesis of diabetic encephalopathy and the mechanisms of ghrelin to ameliorate cognitive dysfunction in diabetic rats. Thirty-six streptozotocin diabetic rat models were established; 12 weeks later, all the rats were randomly divided into 3 groups [diabetic model group (D), ghrelin treatment group (T1), and ghrelin and D-lys-3-GHRP-6 treatment group (T2)] of 12 each. Twelve normoglycemic rats were classified in the normal group (N). Learning and memory behaviors were measured using a spatial version of the Morris water maze test. The brain-derived neurotrophic factor (BDNF), cAMP responsive element binding protein (CREB), phosphorylated CREB (p-CREB), phosphorylated ERK1/2 (p-ERK1/2), caspase-3, and Bcl-xl protein expressions in the hippocampi of all the rats were detected using immunohistochemistry. The mRNA expressions of BDNF, CREB, and caspase-3 were examined using reverse transcription-polymerase chain reaction. The hippocampus neuronal apoptosis was measured by terminal deoxynucleotidyl transferase dUTP nick end labeling method. We found that learning and memory level in the ghrelin treatment group improved significantly, expression of Bcl-xl, BDNF, CREB, p-CREB, and p-ERK1/2 in the hippocampus was increased in the ghrelin treatment group, and the number of apoptotic neurons in the hippocampus decreased remarkably. Our results showed that the changes of BDNF, CREB, and hippocampus neuronal apoptosis might be involved in the pathogenesis of diabetic encephalopathy. We suggested that ghrelin improved cognitive ability in streptozotocin-induced diabetic rats by improving the expressions of BDNF and CREB and by attenuating hippocampus neuronal apoptosis. The effects of ghrelin depend on the receptor of ghrelin, GHSR-1a, and ERK1/2 pathway.

The molecular mechanisms underlying the behavioral effects of glucocorticoids are poorly understood. We report here that hippocampal neuronal nitric oxide synthase (nNOS) is a crucial mediator. Chronic mild stress and glucocorticoids exposures caused hippocampal nNOS overexpression via activating mineralocorticoid receptor. In turn, hippocampal nNOS-derived nitric oxide (NO) significantly downregulated local glucocorticoid receptor expression through both soluble guanylate cyclase (sGC)/cGMP and peroxynitrite (ONOO(-))/extracellular signal-regulated kinase signal pathways, and therefore elevated hypothalamic corticotrophin-releasing factor, a peptide that governs the hypothalamic-pituitary-adrenal axis. More importantly, nNOS deletion or intrahippocampal nNOS inhibition and NO-cGMP signaling blockade (using NO scavenger or sGC inhibitor) prevented the corticosterone-induced behavioral modifications, suggesting that hippocampal nNOS is necessary for the role of glucocorticoids in mediating depressive behaviors. In addition, directly delivering ONOO(-) donor into hippocampus caused depressive-like behaviors. Our findings reveal a role of hippocampal nNOS in regulating the behavioral effects of glucocorticoids.

Drug carriers are generally introduced into the body intravenously and directly exposed to endothelial cells. Silica nanoparticles could be promising delivery vehicles for drug targeting or gene therapy. However, few studies have been undertaken to determine the biological behavior of silica nanoparticles on endothelial cells. Here we measured reactive oxygen species (ROS) generation, apoptosis and necrosis, proinflammatory and prothrombic properties and the levels of the apoptotic signaling proteins and the transcription factors in human umbilical vein endothelial cells (HUVECs) after exposure to silica nanoparticles of different concentrations (25, 50, 100, and 200 microg/mL) for 24h. The results showed that silica nanoparticles, ranging from 50 microg/mL to 200 microg/mL, markedly induced ROS production, mitochondrial depolarization and apoptosis in HUVECs. At the highest concentration, the necrotic rate, LDH leakage, the expression of CD54 and CD62E, and the release of TF, IL-6, IL-8 and MCP-1 were significantly increased. Silica nanoparticles also activated c-Jun N-terminal kinase (JNK), c-Jun, p53, caspase-3 and NF-kappaB, increased Bax expression and suppressed Bcl-2 protein. Moreover, inhibition of ROS attenuated silica nanoparticles-induced apoptosis and inflammation and the activation of JNK, c-Jun, p53 and NF-kappaB. In summary, our findings demonstrated that silica nanoparticles could induce dysfunction of endothelial cells through oxidative stress via JNK, p53 and NF-kappaB pathways, suggesting that exposure to silica nanoparticles may be a significant risk for the development of cardiovascular diseases such as atherosclerosis and thrombus.

BACKGROUND:

Heparan sulfate proteoglycans (HSPGs) at the cell surface play an important role in cell adhesion, spreading, formation of focal adhesion complexes (FACs), and sensing mechanical stress. Syndecans are members of the HSPGs family and are highly expressed in various tumor cells. Syndecan-4 (SDC4) is a unique member of syndecans that activates protein kinase C alpha (PKCα). However, syndecan-4 in tumor cells development is not clear when receiving mechanical stress. Aims: Here we investigate the role of syndecan-4 in tumor cells spreading and its downstream kinases under mechanical stimulation.

METHODS:

Epithelial tumor cells were seeded onto elastomeric polydimethylsiloxane (PDMS) membranes coated with poly-L-lysine (Pl), fibronectin (Fn), or anti-SDC4 antibody and stretched with a modified pressure-driven cell-stretching (PreCS) device.

RESULTS:

When cells received mechanical stimulation, engagement of syndecan-4 promoted the phosphorylation of focal adhesion kinase (FAK) at tyrosine 397 and PKCα at serine 657. Furthermore, we analyzed the cell contractility marker-myosin light chain 2 (MLC2) in 30 min time courses. The levels of phosphorylated MLC2 at serine19 were augmented through ligations of syndecan-4 but not integrin binding motif (RGD) at 10 min mechanical stimulation and were suppressed at 30 min and this phenomenon was associated with the activity of PKCα.

CONCLUSION:

Our data demonstrate that syndecan-4 is essential for transmitting the mechanotransduction signals via activation of PKCα and is important for tumor cells spreading, assembly of actin cytoskeleton and cell contractility.

© 2015 S. Karger AG, Basel.

BACKGROUND:

MT1G inactivation mediated by promoter methylation has been reported in thyroid cancer. However, the role of MT1G in thyroid carcinogenesis remains unclear. The aim of this study is to examine the biological functions and related molecular mechanisms of MT1G in thyroid cancer.

METHODS:

Methylation-specific PCR (MSP) was performed to analyze promoter methylation of MT1G and its relationship with clinicopathological characteristics of papillary thyroid cancer (PTC) patients. Conventional and real-time quantitative RT-PCR assays were used to evaluate mRNA expression. The functions of ectopic MT1G expression were determined by cell proliferation and colony formation, cell cycle and apoptosis, as well as cell migration and invasion assays.

RESULTS:

MT1G expression was frequently silenced or down-regulated in thyroid cancer cell lines, and was also significantly decreased in primary thyroid cancer tissues compared with non-malignant thyroid tissues. Promoter methylation, along with histone modification, contributes to MT1G inactivation in thyroid tumorigenesis. Moreover, our data showed that MT1G hypermethylation was significantly positively associated with lymph node metastasis in PTC patients. Importantly, restoring MT1G expression in thyroid cancer cells dramatically suppressed cell growth and invasiveness, and induced cell cycle arrest and apoptosis through inhibiting phosphorylation of Akt and Rb.

CONCLUSIONS:

We have for the first time revealed that MT1G appears to be functional tumor suppressor involved in thyroid carcinogenesis mainly through modulating the phosphatidylinositol-3-kinase (PI3K)/Akt pathway and partially through regulating the activity of Rb/E2F pathway in this study.

SCOPE:

Flavonoids have well-known antioxidant, anti-inflammatory, and anti-cancer activities. Isoflavone genistein is considered a potent antioxidant agent against oxidative stress. Although several mechanisms have been proposed, a clear antioxidant mechanism of genistein is still remained to be answered.

METHODS AND RESULTS:

In this study, we focused on the concerted effects on expression of Nrf2 and phase II enzyme pathway components. Transient transfection assays, RT-PCR and immunoblot analysis were performed to study its molecular mechanisms of action. In Caco-2 cells, treatment with genistein markedly attenuated H(2)O(2) -induced peroxide formation; this amelioration was reversed by buthionine sulfoximine(GCLC inhibitor) and zinc protoporphyrin(HO-1 inhibitor). Genistein increased HO-1 and GCLC mRNA and protein expression. Genistein treatment activated the ERK1/2 and PKC signaling pathway; therefore increased Nrf2 mRNA and protein expression. The roles of the ERK1/2 and PKC signaling pathway were determined using PD98059 (ERK1/2 inhibitor) and GF109203X (PKC inhibitor) and RNA interference directed against Nrf2. Both inhibitors and siNrf2 abolished genistein-induced HO-1 and GCLC protein expression. These results suggest the involvement of ERK1/2, PKC, and Nrf2 in inducing HO-1 and GCLC by genistein.

CONCLUSION:

Our studies show that genistein up-regulated HO-1 and GCLC expression through the EKR1/2 and PKC /Nrf2 pathways during oxidative stress.

© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

PURPOSE:

In this study, the effect of heparin-derived oligosaccharide (HDO) on vascular endothelial growth factor (VEGF) induced vascular smooth muscle cell (VSMC) proliferation and the signal transduction mechanisms involved were investigated.

METHODS:

MTT assays were used to measure VSMC proliferation, flow cytometry to analyze cell cycle distribution, RT-PCR for detection of gene transcript levels, and cell-based ELISA, Western blotting and immunocytochemical methods to detect the expression of PKC-α, ERK 1/2, p-ERK 1/2, Akt, p-Akt, p-PDK1 and p-GSK-3β.

RESULTS:

HDO at concentrations of 0.01, 0.1 and 1 μmol·L(-1) dose-dependently inhibited VEGF-induced VSMC proliferation with inhibition indices of 6.8 %, 13.1 % and 28.9 %, respectively. Similar concentrations of HDO dose-dependently decreased the percentage of VEGF-induced cells in S phase to 3.6 %, 3.4 %, and 5.4 %, while increasing that of cells arrested in the G0/G1 phase to 80 %, 82 % and 83.6 %. HDO at 0.01, 0.1 or 1 μmol·L(-1) inhibited VEGF-induced PKC-α mRNA expression, with inhibition indices of 9.2 %, 16.1 % and 54.0 %. HDO at 0.1 or 1 μmol·L(-1) inhibited VEGF-induced proto-oncogene mRNA expression, with inhibition indices of 5.2 % and 6.6 % for c-jun, 8.8 % and 11.6 % for c-myc, and 6.5 % and 11.9 % for c-fos, respectively. Additionally, treatment with 0.01, 0.1 or 1 μmol·L(-1) HDO, inhibited VEGF-induced expression of some proliferation related proteins with inhibition indices of 33.2 %, 56.3 % and 77.0 % for PKC-α, 33.7 %, 38.7 % and 53.2 % for p-Akt, 3.5 %, 24.2 % and 49.3 % for p-ERK 1/2, 39.2 %, 71.8 % and 80.7 % for p-PDK 1 and 41.4 %, 89.4 % and 92.4 % for p-GSK-3β, respectively. The results showed that HDO inhibited PKC-α, c-jun, c-fos and c-myc mRNA transcription, and also down-regulated phosphorylation levels of ERK 1/2 and Akt.

CONCLUSION:

Our study demonstrates that HDO inhibits transcription of proliferation-related proto-oncogenes and arrests G1/S transition through inhibition of the PKC, MAPK and Akt/PI3K pathways in association with inhibition of VSMC proliferation. This altered molecular signature may explain one mechanism of HDO-mediated inhibition of VSMC proliferation.

BACKGROUND:

Castration-resistant prostate cancer (CRPC) is a leading cause of cancer-related deaths in elder men. This disease has limited therapeutic options and poor prognosis as the underlying molecular mechanisms are not clearly understood. Given the emerging roles of microRNA (miRNA) as a key regulator, we postulated that miRNA may play a significant role in CRPC formation.

METHODS:

miR-146a levels in 15 androgen-dependent prostate cancer (ADPC) tissues and 5 CRPC tissues were measured by qRT-PCR. Effects of miR-146a in cell proliferation and migration in vitro and in vivo were evaluated by MTT assay, colony formation assay, transwell migratory assay, and tumor formation assay, respectively.

RESULTS:

we found that miR-146a expression was significantly decreased in CRPC tissues compared to ADPC tissues. Functional analyses showed that ectopic overexpression of miR-146a in androgen-independent cell lines not only inhibited cell growth, colony formation, and migration in vitro, but also reduced tumorigenicity and angiogenesis in vivo. Mechanistic studies revealed that miR-146a repressed the expression of EGFR through binding to its 3'-untranslated region. Also, miR-146a inhibited the expression of MMP2, one of the most important genes in tumor progression. Moreover, downregulation of p-ERK expression significantly abrogated miR-146a-induced prostate cancer cell proliferation.

CONCLUSIONS:

Our findings suggest that ubiquitous loss of miR-146a is a critical mechanism for overexpression of EGFR in CRPC, which is crucial to better understanding the pathogenesis of CRPC.

Copyright © 2011 Wiley Periodicals, Inc.

AIM:

We investigated whether 8-dihydroxy-3-methyl-isochromanone (XJP-1), a novel angiotensin-converting enzyme inhibitor (ACEI), exhibited inhibitory activity to lipopolysaccharide (LPS)-accelerated vascular inflammation.

METHODS:

Human umbilical vein endothelial cells (HUVECs) were isolated from human umbilical cords and cultured. The direct effect of XJP-1 on the activation of endothelial cells was measured using MTT assay. Nitric oxide (NO) in the culture medium was measured using Griess method. The expression of cell adhesion molecules (ICAM-1 and VCAM-1) was determined by flow cytometry and RT-PCR. The protein expression levels of tumor necrosis factor-α (TNF-α), monocyte chemotactic protein (MCP)-1, and endothelin-1 (ET-1) secretion were measured using ELISA. Quantitative analysis of eNOS, iNOS, inhibitory factor NF-κB (IκB) and MAPKs were determined using Western blot analysis. The translocation of NF-κB from the cytoplasm to the nucleus was determined using immunofluorescence.

RESULTS:

XJP-1 significantly inhibited LPS-mediated endothelial cell dysfunction, as measured by NO production, iNOS expression, adhesion molecule (ICAM-1, VCAM-1) expression, and chemokine (TNF-α, MCP-1) production in vitro. It up-regulated eNOS expression in the same experimental setting. XJP-1 alone was found non-cytotoxic at the concentration up to 1000μM. The mechanistic investigations of XJP-1 suppression LPS-induced inflammation in HUVECs revealed that XJP-1 blocked NF-κB nuclear entry in an IκB-dependent manner, as well as inhibited MAPK activation induced by LPS. XJP-1 reduced endothelin-1 secretion and increased nitric oxide metabolite production by HUVECs. However, the effect of XJP-1 on nitric oxide and endothelin-1 metabolite production is mediated by the activation of bradykinin B(2) receptor being counteracted, at least in part, by a specific antagonist.

CONCLUSION:

XJP-1 inhibited LPS-induced cytotoxicity and inflammatory response. The mechanism underlying this protective effect might be related to the inhibition of MAPK and NF-κB signaling pathway activation, suggesting the potential inhibition of the atherosclerotic process by suppressing the expression of chemoattractant molecules and monocyte adhesion. XJP-1 also has an effect in improving endothelin-1 through activating bradykinin B(2) receptor. These findings indicated that XJP-1 is potentially a novel therapeutic candidate for the treatment of atherosclerosis.

Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

PURPOSE:

This study was to investigate the clinicopathologic significance and potential role of HOXB7 in the development and progression of colorectal cancer (CRC).

EXPERIMENTAL DESIGN:

The relationship between HOXB7 expression and clinical characteristics of CRC was analyzed in 224 paraffin-embedded archived CRC specimens by immunohistochemistry (IHC). The effects of HOXB7 on cell growth and proliferation, as well as on tumorigenesis, were examined both in vitro and in vivo, using MTT assay, colony formation assay, cell cycle analysis, soft agar assay, and tumorigenesis in nude mice. Western blotting and real-time reverse transcriptase-PCR were performed to examine the impact of HOXB7 on the PI3K/Akt and MAPK signaling pathways.

RESULTS:

HOXB7 protein level was significantly correlated with advanced Dukes stage (P < 0.001), T stage (P = 0.012), distant metastasis (P = 0.042), higher proliferation index (P = 0.007) and poor survival of patients (P = 0.005). Enforced expression of HOXB7 in CRC cell lines significantly enhanced cell growth, proliferation and tumorigenesis. Conversely, knockdown of HOXB7 caused an inhibition of cell growth, proliferation, and tumorigenesis. We also showed that HOXB7 accelerated G(0)-G(1) to S-phase transition concomitantly with upregulation of cyclin D1 and downregulation of p27Kip1. On the contrary, knockdown of HOXB7 caused G(1)-S-phase arrest, downregulation of cyclin D1 and upregulation of p27Kip1. Enforced expression of HOXB7 could enhance PI3K/AKT and MAPK pathway activity.

CONCLUSION:

Our findings suggest that HOXB7 protein, as a valuable marker of CRC prognosis, plays an important role in the development and progression of human CRC.

©2011 AACR.

BACKGROUND:

Previous studies showed that connective tissue growth factor (CTGF)-induced proliferation of lung fibroblasts and production of chemokines in mesangial cells could be inhibited by lipoxin A(4) (LXA(4)). It is speculated that LXA(4) could modulate the CTGF-induced epithelial to mesenchymal transition.

METHODS:

The expressions of alpha-smooth muscle actin (alpha-SMA), E-cadherin, integrin-linked kinase (ILK), extracellular signal-regulated kinase 1/2 (ERK1/2), phosphatidylinositol 3-kinase (PI3-K), Akt and Smad signaling were assessed by Western blot and/or real-time RT-PCR, and activation of Ras or ILK by activity assay, expressions of alpha-SMA and zonula occludens-1 by immunofluorescence assay in proximal tubular epithelial cells (HK-2).

RESULTS:

Pretreatment of HK-2 cells with LXA(4) inhibited the morphological fibroblast-like changes and alpha-SMA expression induced by CTGF but not by transforming growth factor-beta(1) (TGF-beta(1)). The expressions of E-cadherin and zonula occludens-1 reduced by CTGF but not by TGF-beta(1) were increased by LXA(4). LXA(4) inhibited the expression and activity of ILK and activation of Ras, ERK1/2, PI3-K and Akt in HK-2 cells stimulated by CTGF. LXA(4) did not affect TGF-beta(1)-induced expression of ILK, Smad-2/3 phosphorylation and Smad-2's binding to Smad-4 and subsequent nuclear translocation.

CONCLUSION:

LXA(4) inhibits the tubular epithelial to mesenchymal transition, initiated by CTGF but not by TGF-beta(1), via downregulation of ILK, Ras/MEK/ERK1/2 and PI3-K/Akt-dependent signal pathway stimulated by CTGF.

2010 S. Karger AG, Basel.