title: Silencing of microRNA-122 is an early event during hepatocarcinogenesis from non-alcoholic steatohepatitis.
abstract: Non-alcoholic steatohepatitis (NASH) has emerged as a common cause of chronic liver disease and virus-independent hepatocellular carcinoma (HCC) in patients with obesity, diabetes, and metabolic syndrome. To reveal the molecular mechanism underlying hepatocarcinogenesis from NASH, microRNA (miRNA) expression profiles were analyzed in STAM mice, a NASH-HCC animal model. MicroRNA expression was also examined in 42 clinical samples of HCC tissue. Histopathological images of the liver of STAM mice at the ages of 6, 8, 12, and 18 weeks showed findings compatible with fatty liver, NASH, liver cirrhosis (LC), and HCC, respectively. Expression of miR-122 in non-tumor LC at the age of 18 weeks was significantly lower than that in LC at the age of 12 weeks. Expression of miR-122 was further decreased in HCCs relative to non-tumor LC at the age of 18 weeks. Expression of miR-122 was also decreased in clinical samples of liver tissue showing macrovesicular steatosis and HCC, being consistent with the findings in the NASH model mice. DNA methylation analysis revealed that silencing of miR-122 was not mediated by DNA hypermethylation of the promoter region. These results suggest that silencing of miR-122 is an early event during hepatocarcinogenesis from NASH, and that miR-122 could be a novel molecular marker for evaluating the risk of HCC in patients with NASH.
authors.affiliation: Division of Pharmacotherapeutics, Keio University Faculty of Pharmacy, Tokyo, Japan.
authors.forename: Yoko
authors.initials: Y
authors.lastname: Takaki
authors.forename: Yoshimasa
authors.initials: Y
authors.lastname: Saito
authors.forename: Azusa
authors.initials: A
authors.lastname: Takasugi
authors.forename: Kohta
authors.initials: K
authors.lastname: Toshimitsu
authors.forename: Shoji
authors.initials: S
authors.lastname: Yamada
authors.forename: Toshihide
authors.initials: T
authors.lastname: Muramatsu
authors.forename: Masaki
authors.initials: M
authors.lastname: Kimura
authors.forename: Kazuo
authors.initials: K
authors.lastname: Sugiyama
authors.forename: Hiromu
authors.initials: H
authors.lastname: Suzuki
authors.forename: Eri
authors.initials: E
authors.lastname: Arai
authors.forename: Hidenori
authors.initials: H
authors.lastname: Ojima
authors.forename: Yae
authors.initials: Y
authors.lastname: Kanai
authors.forename: Hidetsugu
authors.initials: H
authors.lastname: Saito
mesh_terms: D000818:Animals; D001483:Base Sequence; D006528:Carcinoma, Hepatocellular / Q000209:etiology* / Q000235:genetics; D045744:Cell Line, Tumor; D019175:DNA Methylation; D020868:Gene Silencing; D056945:Hep G2 Cells; D006801:Humans; D008113:Liver Neoplasms / Q000209:etiology* / Q000235:genetics; D008297:Male; D008810:Mice, Inbred C57BL; D035683:MicroRNAs / Q000235:genetics*; D008969:Molecular Sequence Data; D065626:Non-alcoholic Fatty Liver Disease / Q000150:complications*; D011401:Promoter Regions, Genetic
chemical_list: C531907:MIRN122 microRNA, human; D035683:MicroRNAs
keywords: Fatty liver; hepatocellular carcinoma; miR-122; microRNA; non-alcoholic steatohepatitis