title: HCV core protein-induced down-regulation of microRNA-152 promoted aberrant proliferation by regulating Wnt1 in HepG2 cells.
abstract: BACKGROUND
  Hepatitis C virus (HCV) has been reported to regulate cellular microRNAs (miRNAs). The HCV core protein is considered to be a potential oncoprotein in HCV-related hepatocellular carcinoma (HCV-HCC), but HCV core-regulated miRNAs are largely unknown. Our preliminary experiments revealed significant down-regulation of microRNA-152 (miR-152) by HCV core protein in HepG2 cells. Through target gene prediction softwares, Wnt1 was predicted to be a potential target of miR-152. The present study was initiated to investigate whether miR-152 is aberrantly regulated by the HCV core protein, and involved in the regulation of the aberrant proliferation of HCV-HCC cells.
  
  
  METHODS
  MiR-152 levels were examined by stem-loop real-time RT-PCR (SLqRT-PCR). Cell proliferation was analyzed by MTT and colony formation assay. Cell cycle analysis was performed by flow cytometry. Luciferase reporter assay was conducted to confirm miRNA-target association. Wnt1 expression was determined by real-time qPCR and Western blotting.
  
  
  RESULTS
  HCV core protein significantly suppressed miR-152 expression, and led to significant Wnt1 up-regulation with a concomitant aberrantly promoted proliferation. Moreover, we validated that miR-152 inhibition promoted, while miR-152 mimics inhibited cell proliferation. Using, qRT-PCR and western blot, Wnt1 was demonstrated to be regulated by miR-152. Luciferase activity assay showed that while miR-152 mimics significantly reduced the luciferase activity by 83.76% (P<0.0001), miR-152 inhibitor showed no effect on luciferase reporter. Most notably, salvage expression of miR-152 after Ad-HCV core infection for 24 h almost totally reversed the proliferation-promoting effect of the HCV core protein, and meanwhile, reduced the expression of both Wnt1 mRNA and protein to basal levels.
  
  
  CONCLUSIONS
  These findings provide important evidence that the reduced miR-152 expression by HCV core protein can indirectly lose an inhibitory effect on Wnt1, which might, at least partially lead to cell proliferation of liver cancer cells. MiR-152 may have a therapeutic potential to suppress liver cancer proliferation.
authors.affiliation: Department of Laboratory Medicine, the First Affiliated Hospital of Chongqing Medical University, Chongqing, China.
authors.forename: Shifeng
authors.initials: S
authors.lastname: Huang
authors.affiliation: Department of Laboratory Medicine, the First Affiliated Hospital of Chongqing Medical University, Chongqing, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Xie
authors.affiliation: Department of Laboratory Medicine, the First Affiliated Hospital of Chongqing Medical University, Chongqing, China.
authors.forename: Ping
authors.initials: P
authors.lastname: Yang
authors.affiliation: Department of Laboratory Medicine, the First Affiliated Hospital of Chongqing Medical University, Chongqing, China.
authors.forename: Pu
authors.initials: P
authors.lastname: Chen
authors.affiliation: Department of Laboratory Medicine, the First Affiliated Hospital of Chongqing Medical University, Chongqing, China.
authors.forename: Liping
authors.initials: L
authors.lastname: Zhang
mesh_terms: D000256:Adenoviridae / Q000378:metabolism; D001483:Base Sequence; D049109:Cell Proliferation; D015536:Down-Regulation / Q000235:genetics*; D016193:G1 Phase / Q000235:genetics; D015972:Gene Expression Regulation, Neoplastic; D056945:Hep G2 Cells; D016174:Hepacivirus / Q000378:metabolism*; D006801:Humans; D035683:MicroRNAs / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D016196:S Phase / Q000235:genetics; D014410:Tumor Stem Cell Assay; D015854:Up-Regulation / Q000235:genetics; D014758:Viral Core Proteins / Q000378:metabolism*; D051155:Wnt1 Protein / Q000235:genetics* / Q000378:metabolism
chemical_list: C550856:MIRN152 microRNA, human; D035683:MicroRNAs; D012333:RNA, Messenger; D014758:Viral Core Proteins; C495247:WNT1 protein, human; D051155:Wnt1 Protein