Anti-Histone H2A.X (phospho-S139) Anticorpo (A27711)

H4K20me1 is a critical histone lysine methyl modification in eukaryotes. It is recognized and "read" by various histone lysine methyl modification binding proteins. In this study, the function of MBTD1, a member of the Polycomb protein family containing four MBT domains, was comprehensively studied in mouse oocyte meiotic maturation. The results showed that depletion of MBTD1 caused reduced expression of histone lysine methyl transferase Pr-Set7 and H4K20me1 as well as increased oocyte arrest at the GV stage. Increased γH2AX foci were formed, and DNA damage repair checkpoint protein 53BP1 was downregulated. Furthermore, depletion of MBTD1 activated the cell cycle checkpoint protein Chk1 and downregulated the expression of cyclin B1 and cdc2. MBTD1 knockdown also affected chromosome configuration in GV stage oocytes and chromosome alignment at the MII stage. All these phenotypes were reproduced when the H4K20 methyl transferase Pr-Set7 was depleted. Co-IP demonstrated that MBTD1 was correlated with Pr-Set7 in mouse oocytes. Our results demonstrate that MBTD1 is associated with Pr-Set7 to stabilize H4K20me1 in mouse oocyte meiotic maturation.

In this study, Hydroxycamptothecin (HCPT)-loaded micelles were formed in water by the self-assembly of folate (FA)-decorated amphiphilic block copolymer, methoxy poly(ethylene glycol)-poly(ε-caprolactone) (MPEG-PCL), and achieved a hydrodynamic diameter about of 132 nm. HCPT release from the micelles exhibited no initial burst but showed a sustained release profile. The cytotoxicity and targeting ability of FA conjugated polymeric micelles was investigated by using methylthiazoletetrazolium (MTT) and fluorescence microscopy. We found that FA-conjugated micelles had superior cytotoxicity against HeLa cells compared to non-conjugated micelles, and that they exerted this effect by folate receptor (FR)-mediated endocytosis. In addition, HeLa cells were xenografted into nude mice and subjected to radiotherapy (RT) and/or HCPT-loaded micelle treatment. The antitumor efficacy was detected by analysis of tumor growth delay (TGD) and median survival time. Micro fluorine-18-deoxyglucose PET/computed tomography ((18)F-FDG PET/CT) was performed to assess early tumor response to HCPT-loaded micelles in combination with RT. Analysis of cell cycle redistribution, apoptosis and expression of histone H2AX phosphorylation (λ-H2AX) was used to evaluate the mechanism by which HCPT loaded micelles led to radiosensitization. Taken together, the results showed that HCPT-loaded FA decorated micelles efficiently sensitized xenografts in mice to RT, and induced G2/M phase arrest, apoptosis and expression of λ-H2AX.

DNA damage has recently been shown to inhibit or delay germinal vesicle breakdown (GVBD) in mouse oocytes, but once meiosis resumes, DNA-damaged oocytes are able to extrude the first polar body. In this study, using porcine oocytes, we showed that DNA damage did not affect GVBD, but inhibited the final stages of maturation, as indicated by failure of polar body emission. Unlike mitotic cells in which chromosome mis-segregation causes DNA double-strand breaks, meiotic mouse oocytes did not show increased DNA damage after disruption of chromosome attachment to spindle microtubules. Nocodazole-treated oocytes did not display increased DNA damage signals that were marked by γH2A.X signal strength, but reformed spindles and underwent maturation, although aneuploidy increased after extended nocodazole treatment. By using the mouse for parthenogenetic activation studies, we showed that early cleavage stage embryos derived from parthenogenetic activation of nocodazole-treated oocytes displayed normal activation rate and normal γH2A.X signal strength, indicating that no additional DNA damage occured. Our results suggest that DNA damage inhibits porcine oocyte maturation, while nocodazole-induced dissociation between chromosomes and microtubules does not lead to increased DNA damage either in mouse meiotic oocytes or in porcine oocytes.

Nanotechnology is one of today's most promising technological developments, but safety concerns raise questions about its development. Risk assessments of nanomaterials during occupational exposure are crucial for their development. Here, we assessed the lung toxicity of functionalized single-walled carbon nanotube (f-SWCNT) exposure in C57BL/6 mice, elucidated the underlying molecular mechanism, and evaluated the self-repair ability and lung fibrosis of the mice. Soluble f-SWCNTs were administered to mice. After 18 h or 14 days, the lung histopathology, bronchoalveolar lavage fluid, lung edema, vascular permeability, and PaO(2) levels were evaluated, and biochemical and immunostaining tests were also performed. We found that some f-SWCNTs could induce acute lung injury (ALI) in mice via proinflammatory cytokine storm signaling through the NF-κB pathway in vivo. We illustrated that corticosteroid treatments could ameliorate the ALI induced by the f-SWCNTs in mice. Surprisingly, the ALI was almost completely reversed within 14 days, while mild to moderate fibrosis, granuloma, and DNA damage remained in the mice at day 14. Our studies indicate potential remedies to address the growing concerns about the safety of nanomaterials. In addition, we notify that the type of functional groups should be considered in nanomedicine application as differently functionalized SWCNTs generated different effects on the lung toxicity.

BACKGROUND:

High Mobility Group N (HMGN) proteins are a family of chromatin structural proteins that specifically bind to nucleosome core particles. HMGN5 is a novel and characteristic member of the HMGN protein family. We have previously found that HMGN5 is upregulated in prostate cancer and its downregulation had been demonstrated to induce apoptosis and G2-M cell cycle arrest.

METHODS:

The radiosensitization effect of HMGN5 knockdown on PC3 and DU145 cells was assessed using clonogenic assay, flow cytometry, and comet assay. The DNA double-strand break (DSB) repair kinetics of HMGN5 knockdown and control cells after radiation exposure was evaluated using immunocytofluorescence. The mitochondrial reactive oxygen species (ROS) levels were estimated using Dihydrorhodamine 123 (DHR 123) probes. Expression of mitochondrial antioxidant MnSOD was measured by real-time PCR and Western blot. The expression of antiapoptotic proteins Bcl-2 and Bcl-xL as well as cleavage of caspase-3, caspase-9, and PARP were also measured using Western blot.

RESULTS:

HMGN5 knockdown cells exhibit decreased clonogenic survival and increased apoptosis rate in response to 2-8 Gy ionizing radiation (IR). Loss of HMGN5 does not affect the DSB repair kinetics after radiation exposure. HMGN5 knockdown cells demonstrated increased mitochondrial ROS level and suppressed induction of MnSOD upon radiation compared with control cells upon radiation. Further, MnSOD knockdown resulted in inhibited cell viability as well as increased mitochondrial ROS level and apoptosis upon radiation in PC3 and DU145 cells. Finally, HMGN5 knockdown cells showed significantly decreased levels of antiapoptotic proteins Bcl-2 and Bcl-xL as well as increased cleavage of caspase-3, caspase-9, and PARP compared with control cells after radiation.

CONCLUSIONS:

HMGN5 knockdown sensitizes prostate cancer cells to ionizing radiation, and the radiosensitization effect may be partially mediated through suppressed induction of MnSOD and enhanced activation of apoptosis pathway in response to IR.

© 2014 Wiley Periodicals, Inc.

BACKGROUND:

Epithelial-mesenchymal transition (EMT) plays a pivotal role in the development of metastatic cancers. Basic fibroblast growth factor (bFGF) is significantly elevated in metastatic prostate cancers, which has been mentioned mainly to induce EMT in normal cells. However, there is no description about bFGF induced EMT and its underlying mechanism in prostate cancer cells.

METHODS:

Western blotting, immunofluorescence and qRT-PCR assays were used to study protein or mRNA expression profiles of the EMT. Wound healing scratch, migration and invasion assays were used to test the motility of cells undergoing EMT. More methods were used to explore the underlying mechanisms.

RESULTS:

We demonstrated that bFGF promoted EMT and motility of human prostate cancer PC-3 cells. Both protein and mRNA expression of Snail were rapidly increased after bFGF treatment. Ectopic expression of Snail triggered EMT and enhanced cell motility in PC-3 cells, and knockdown of Snail almost abolished bFGF induced EMT, suggesting the critical role of Snail. Mechanistic study demonstrated that bFGF promoted the stability, nuclear localization and transcription of Snail by inhibiting the activity of glycogen synthase kinase 3 beta (GSK-3β) through phosphatidylinositide 3 kinases (PI3K)/protein kinase B (AKT) signaling pathway.

CONCLUSIONS:

It is concluded that bFGF can promote EMT and motility of PC-3 cells, and AKT/GSK-3β signaling pathway controls the stability, localization and transcription of Snail which is crucial for this bFGF induced EMT.

GENERAL SIGNIFICANCE:

To our knowledge, this is the first study to demonstrate that bFGF can induce EMT via AKT/GSK-3β/Snail signaling pathway in prostate cancer cells.

Copyright © 2014 Elsevier B.V. All rights reserved.