title: Epigenetic dysregulation in hepatocellular carcinoma: focus on polycomb group proteins.
abstract: Hepatocellular carcinoma (HCC) development is characterized by the presence of epigenetic alterations, including promoter DNA hypermethylation and post-translational modifications of histone, which profoundly affect expression of a wide repertoire of genes critical for cancer development. Emerging data suggest that deregulation of polycomb group (PcG) proteins, which are key chromatin modifiers repressing gene transcription during developmental stage, plays a causative role in oncogenesis. PcG proteins assemble into polycomb repressive complex 1 (PRC1) and polycomb repressive complex 2 (PRC2) to impose the histone H3 lysine 27 trimethylation (H3K27me3) modification for repression. In this review, we will first recapitulate the mechanisms of two key epigenetic pathways: DNA methylation and histone modifications. Specifically, we will focus our discussion on the molecular roles of PcG proteins. Next, we will highlight recent findings on PcG proteins, their clinicopathological implication and their downstream molecular consequence in hepatocarcinogenesis. Last but not least, we will consider the therapeutic potential of targeting enhancer of zeste homolog 2 (EZH2) as a possible treatment for HCC. Improving our understanding on the roles of PcG proteins in hepatocarcinogenesis can benefit the development of epigenetic-based therapy.
authors.affiliation: State Key Laboratory for Liver Research and Department of Pathology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China.
authors.forename: Sandy Leung-Kuen
authors.initials: SL
authors.lastname: Au
authors.forename: Irene Oi-Lin
authors.initials: IO
authors.lastname: Ng
authors.forename: Chun-Ming
authors.initials: CM
authors.lastname: Wong
mesh_terms: D006528:Carcinoma, Hepatocellular / Q000235:genetics* / Q000378:metabolism; D057890:Epigenomics / Q000379:methods*; D006801:Humans; D008113:Liver Neoplasms / Q000235:genetics* / Q000378:metabolism; D063146:Polycomb-Group Proteins / Q000235:genetics* / Q000378:metabolism
chemical_list: D063146:Polycomb-Group Proteins