title: Downregulation of catalase by reactive oxygen species via hypermethylation of CpG island II on the catalase promoter.
abstract: Catalase, which decomposes reactive oxygen species (ROS), is reduced in hepatocellular carcinoma (HCC); however, the reasons are poorly defined. In this study, it is demonstrated that prolonged exposure to ROS induced methylation of CpG island II on the catalase promoter and downregulated catalase expression at the transcriptional level in HCC cell lines. In addition, hypermethylation of CpG island II was also observed in tumor tissues, together with a decrease in catalase mRNA and protein expression levels when compared to non-tumor tissues. From these data, we suggest that ROS may downregulate catalase through the methylation of promoter during the development of HCC.
authors.affiliation: The Department of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul, South Korea.
authors.forename: Ji Young
authors.initials: JY
authors.lastname: Min
authors.forename: Seung-Oe
authors.initials: SO
authors.lastname: Lim
authors.forename: Guhung
authors.initials: G
authors.lastname: Jung
mesh_terms: D000818:Animals; D006528:Carcinoma, Hepatocellular / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D002374:Catalase / Q000235:genetics* / Q000378:metabolism; D018899:CpG Islands; D019175:DNA Methylation; D015536:Down-Regulation / Q000187:drug effects*; D008113:Liver Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D008745:Methylation / Q000187:drug effects; D012333:RNA, Messenger / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000494:pharmacology*; D012045:Regulatory Sequences, Nucleic Acid
chemical_list: D012333:RNA, Messenger; D017382:Reactive Oxygen Species; D002374:Catalase