The hepatitis B virus×protein (HBx) has been implicated as a potential trigger of the epigenetic deregulation of some genes, but the underlying mechanism remains unknown. The aim of this study is to identify underlying mechanisms involved in HBx-mediated epigenetic modification in the process of HBx induced p16(INK4A) promoter hypermethylation. Liver cell lines were stably transfected with HBx-expressing vector. The methylation status of p16(INK4A) was examined by methyl-specific polymerase chain reaction (MSP) and bisulfite sequencing. Reverse transcription and real-time polymerase chain reaction (real-time RT-PCR), Western blot and immunohistochemistry were used to analyze the expression of HBx, HBx-mediated DNA methylation abnormalities and p16(INK4A). Some cases of HCC and corresponding noncancerous liver tissues were studied. HBx up-regulates DNMT1 and DNMT3A expression in both mRNA level and protein level, and HBx represses p16(INK4A) expression through inducing hypermethylation of p16(INK4A) promoter. Moreover, HBx induces hypermethylation of p16(INK4A) promoter through DNMT1 and DNMT3A. Regulation of DNMT1 and DNMT3A by HBx promoted hypermethylation of p16(INK4A) promoter region. HBx-DNMTs-p16(INK4A) promoter hypermethylation may suggest a mechanism for tumorigenesis during hepatocarcinogenesis.
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http://dx.doi.org/10.1016/j.yexmp.2010.06.013 | DOI Listing |
FEBS J
January 2025
Université d'Angers, Inserm, CNRS, CRCI2NA, ICO, Angers, France.
Senescence is a tumor suppressor mechanism triggered by oncogene expression and chemotherapy treatment. It orchestrates a definitive cessation of cell proliferation through the activation of the p53-p21 and p16-Rb pathways, coupled with the compaction of proliferative genes within heterochromatin regions. Some cancer cells have the ability to elude this proliferative arrest but the signaling pathways involved in circumventing senescence remain to be characterized.
View Article and Find Full Text PDFNeoplasia
December 2024
Department of Pathology, Ajou University School of Medicine, Suwon 16499, Republic of Korea. Electronic address:
Glioblastoma, isocitrate dehydrogenase (IDH)-wildtype (GBM), is the most malignant brain tumor in adults, with limited therapeutic intervention. Previous studies have identified a few prognostic markers for GBM, including the methylation status of O-methylguanine-DNA methyltransferase (MGMT) promoter, TERT promoter mutation, EGFR amplification, and CDKN2A/2B deletion. However, the classification of GBM remains incomplete, necessitating a comprehensive analysis.
View Article and Find Full Text PDFClin Appl Thromb Hemost
December 2024
Department of Hematology and Transfusion sciences, School of Allied Medical Sciences, Tehran University of Medical sciences, Tehran, Iran.
Objective: DNA methylation, as an epigenetic alteration, plays an essential role in the development of atherosclerosis and venous thrombosis. E-cadherin, a tumor suppressor gene and adhesion molecule, has a crucial function in platelet aggregation and hemostasis. P16, a cell cycle regulator, is involved in venous thrombosis.
View Article and Find Full Text PDFInt J Mol Sci
November 2024
Department of Biophysics of Environmental Pollution, Faculty of Biology and Environmental Protection, University of Lodz, Pomorska Str. 141/143, 90-236 Lodz, Poland.
The aim of the present study was to investigate the concentration- and size-dependent effects of non-functionalized polystyrene nanoparticles (PS-NPs) of varying diameters (29 nm, 44 nm, and 72 nm) on specific epigenetic modifications and gene expression profiles related to carcinogenesis in human peripheral blood mononuclear cells (PBMCs) in vitro. This in vitro human-cell-based model is used to investigate the epigenetic effect of various environmental xenobiotics. PBMCs were exposed to PS-NPs at concentrations ranging from 0.
View Article and Find Full Text PDFCell Death Dis
November 2024
Department of Thoracic Surgery, Tongji Hospital, Huazhong University of Science and Technology, Wuhan, China.
Polycomb repressive complex 2 (PRC2) catalyzes the writing of the tri-methylated histone H3 at Lys27 (H3K27me3) epigenetic marker and suppresses the expression of genes, including tumor suppressors. The function of the complex can be partially antagonized by the SWI/SNF chromatin-remodeling complex. Previous studies have suggested that PRC2 is important for the proliferation of tumors with SWI/SNF loss-of-function mutations.
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