title: Global DNA methylation screening of liver in piperonyl butoxide-treated mice in a two-stage hepatocarcinogenesis model.
abstract: Disruptive epigenetic gene control has been shown to be involved in carcinogenesis. To identify key molecules in piperonyl butoxide (PBO)-induced hepatocarcinogenesis, we searched hypermethylated genes using CpG island (CGI) microarrays in non-neoplastic liver cells as a source of proliferative lesions at 25 weeks after tumor promotion with PBO using mice. We further performed methylation-specific polymerase chain reaction (PCR), real-time reverse transcription PCR, and immunohistochemical analysis in PBO-promoted liver tissues. Ebp4.1, Wdr6 and Cmtm6 increased methylation levels in the promoter region by PBO promotion, although Cmtm6 levels were statistically non-significant. These results suggest that PBO promotion may cause altered epigenetic gene regulation in non-neoplastic liver cells surrounding proliferative lesions to allow the facilitation of hepatocarcinogenesis. Both Wdr6 and Cmtm6 showed decreased expression in non-neoplastic liver cells in contrast to positive immunoreactivity in the majority of proliferative lesions produced by PBO promotion. These results suggest that both Wdr6 and Cmtm6 were spared from epigenetic gene modification in proliferative lesions by PBO promotion in contrast to the hypermethylation-mediated downregulation in surrounding liver cells. Considering the effective detection of proliferative lesions, these molecules could be used as detection markers of hepatocellular proliferative lesions and played an important role in hepatocarcinogenesis.
authors: Laboratory of Veterinary Pathology, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu-shi, Tokyo 183-8509, Japan; Pathogenetic Veterinary Science, United Graduate School of Veterinary Sciences, Gifu University, 1-1 Yanagido, Gifu-shi, Gifu 501-1193, Japan.
authors: Atsunori
authors: A
authors: Yafune
authors: Masaomi
authors: M
authors: Kawai
authors: Megu
authors: M
authors: Itahashi
authors: Masayuki
authors: M
authors: Kimura
authors: Fumiyuki
authors: F
authors: Nakane
authors: Kunitoshi
authors: K
authors: Mitsumori
authors: Makoto
authors: M
authors: Shibutani
mesh_terms: D000818:Animals; D015197:Carcinogenicity Tests; D002273:Carcinogens / Q000633:toxicity*; D018899:CpG Islands / Q000187:drug effects; D019175:DNA Methylation / Q000187:drug effects*; D008099:Liver / Q000187:drug effects*; D008114:Liver Neoplasms, Experimental / Q000139:chemically induced*; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D010882:Piperonyl Butoxide / Q000633:toxicity*; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D002273:Carcinogens; D010882:Piperonyl Butoxide
keywords: CGI; CKLF-like MARVEL transmembrane domain-containing protein 6; Cmtm6; CpG island; DEN; Hepatocarcinogenesis; Methylation; Mouse; N-diethylnitrosamine; PBO; Piperonyl butoxide; WD repeat domain 6; Wdr6; piperonyl butoxide