title: miR-106b downregulates adenomatous polyposis coli and promotes cell proliferation in human hepatocellular carcinoma.
abstract: Aberrant activation of the Wnt/β-catenin signal pathway is frequently observed in hepatocellular carcinoma (HCC). β-Catenin is the major cellular effector of Wnt signaling and inactivation of adenomatous polyposis coli (APC) results in nuclear accumulation of β-catenin. Therefore, it was speculated that APC inhibition could play important roles in activating the Wnt/β-catenin pathway and in HCC progression. In this study, we report that miR-106b expression is markedly upregulated in hepatoma cells and hepatoma tissues compared with immortalized normal liver epithelial cells and normal hepatic tissues. Ectopic expression of miR-106b induces the proliferation and anchorage-independent growth of hepatoma cells, whereas inhibition of miR-106b reduced this effect. Furthermore, miR-106b upregulation in hepatoma cells modulated entry into the G(1)/S transitional phase by upregulating cyclin D1 and downregulating APC. Moreover, we demonstrated that miR-106b downregulates APC expression by directly targeting the 3'-untranslated region of APC messenger RNA. Taken together, our results suggest that miR-106b plays an important role in promoting the proliferation of human hepatoma cells and presents a novel mechanism of micro RNA-mediated direct suppression of APC expression in cancer cells.
authors.affiliation: Department of Radiology, The Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong 510260,  China.
authors.forename: Gang
authors.initials: G
authors.lastname: Shen
authors.forename: Hongyun
authors.initials: H
authors.lastname: Jia
authors.forename: Qiang
authors.initials: Q
authors.lastname: Tai
authors.forename: Yanhao
authors.initials: Y
authors.lastname: Li
authors.forename: Deji
authors.initials: D
authors.lastname: Chen
mesh_terms: D001483:Base Sequence; D006528:Carcinoma, Hepatocellular / Q000235:genetics / Q000473:pathology*; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D017931:DNA Primers; D015536:Down-Regulation / Q000502:physiology*; D017491:Genes, APC; D006801:Humans; D008113:Liver Neoplasms / Q000235:genetics / Q000473:pathology*; D035683:MicroRNAs / Q000502:physiology*; D060888:Real-Time Polymerase Chain Reaction
chemical_list: D017931:DNA Primers; C542541:MIRN106 microRNA, human; D035683:MicroRNAs