title: MicroRNA-122 suppresses cell proliferation and induces cell apoptosis in hepatocellular carcinoma by directly targeting Wnt/β-catenin pathway.
abstract: OBJECTIVE
  To validate whether the anti-cancer effect of microRNA-122 (miR-122) on hepatocellular carcinoma (HCC) is mediated through regulating Wnt/β-catenin signalling pathways.
  
  
  METHODS
  The expression levels of miR-122 in HCC tissues and varied hepatoma cells were quantified by real-time PCR. MiR-122 agomir was transfected into HepG2, Hep3B cells to over-express miR-122. The effect of over-expression miR-122 on proliferation and apoptosis of HepG2 and Hep3B cells was evaluated using CCK-8 kit and flow cytometer respectively. The 3'-UTR segments of Wnt1 containing the miR-122 binding sites were amplified by PCR and the luciferase activity in the transfected cells was assayed. Wnt1 mRNA level was quantified using RT-PCR. Protein levels of Wnt1, β-catenin and TCF-4 were detected using Western blotting.
  
  
  RESULTS
  In comparison with the expression level of miR-122 in para-cancerous tissues or Chang liver cell, the expression level in HCC tissues or varied hepatoma cells was significantly decreased (P < 0.05). Over-expression of miR-122 significantly inhibited the proliferation (P < 0.05), and promoted the apoptosis of HepG2 and Hep3B cells. Over-expressed miR-122 down-regulated the protein levels of Wnt1, β-catenin and TCF-4 (P < 0.05). MiR-122 suppressed the luciferase activity of the pmiR-Wnt1-wt by approximately 50% compared with the negative control, while mutation or removal of the miR-122 binding site using siRNA or mir-122 inhibitor blocked the suppressive effect (P < 0.05).
  
  
  CONCLUSIONS
  MiR-122 expression is down-regulated in human HCC. Over-expression of miR-122 inhibits HCC cell growth and promotes the cell apoptosis by affecting Wnt/β-catenin-TCF signalling pathway.
authors.affiliation: Department of Oncological Surgery, the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Xu
authors.forename: Xiuming
authors.initials: X
authors.lastname: Zhu
authors.forename: Lingjiao
authors.initials: L
authors.lastname: Wu
authors.forename: Rong
authors.initials: R
authors.lastname: Yang
authors.forename: Zeran
authors.initials: Z
authors.lastname: Yang
authors.forename: Qiangfeng
authors.initials: Q
authors.lastname: Wang
authors.forename: Fusheng
authors.initials: F
authors.lastname: Wu
mesh_terms: D017209:Apoptosis / Q000235:genetics*; D006528:Carcinoma, Hepatocellular / Q000378:metabolism / Q000473:pathology*; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D002470:Cell Survival / Q000235:genetics; D015536:Down-Regulation; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D018390:Gene Targeting; D006801:Humans; D008113:Liver Neoplasms / Q000378:metabolism / Q000473:pathology*; D008297:Male; D035683:MicroRNAs / Q000502:physiology*; D008875:Middle Aged; D060449:Wnt Signaling Pathway / Q000235:genetics*
chemical_list: C531907:MIRN122 microRNA, human; D035683:MicroRNAs