title: The putative tumour suppressor microRNA-124 modulates hepatocellular carcinoma cell aggressiveness by repressing ROCK2 and EZH2.
abstract: BACKGROUND
  Recent profile studies of microRNA (miRNA) expression have documented a deregulation of miRNA (miR-124) in hepatocellular carcinoma (HCC).
  
  
  OBJECTIVE
  To determine the status of miR-124 expression and its underlying mechanisms in the pathogenesis of HCC.
  
  
  METHODS
  The expression levels of miR-124 were first examined in HCC cell lines and tumour tissues by real-time PCR. The in vitro and in vivo functional effect of miR-124 was examined further. A luciferase reporter assay was conducted to confirm target associations.
  
  
  RESULTS
  The expression levels of miR-124 were frequently reduced in HCC cells and tissues, and low-level expression of miR-124 was significantly associated with a more aggressive and/or poor prognostic phenotype of patients with HCC (p<0.05). In HCC cell lines, stable overexpression of miR-124 was sufficient to inhibit cell motility and invasion in vitro, and suppress intrahepatic and pulmonary metastasis in vivo. In addition, ectopic overexpression of miR-124 in HCC cells inhibited epithelial-mesenchymal cell transition, formation of stress fibres, filopodia and lamellipodia. Further studies showed that miR-124 could directly target the 3'-untranslated region (3'-UTR) of both ROCK2 and EZH2 mRNAs, and suppress their mRNA and protein expressions. These findings suggest that miR-124 plays a critical role in regulating cytoskeletal events and epithelial-mesenchymal cell transition and, ultimately, inhibits the invasive and/or metastatic potential of HCC, probably by its direct target on ROCK2 and EZH2 genes. These results provide functional and mechanistic links between the tumour suppressor miRNA-124 and the two oncogenes ROCK2 and EZH2 on the aggressive nature of HCC.
  
  
  CONCLUSIONS
  These data highlight an important role for miR-124 in the regulation of invasion and metastasis in the molecular aetiology of HCC, and suggest a potential application of miR-124 in prognosis prediction and cancer treatment.
authors.affiliation: The State Key Laboratory of Oncology in South China, Sun Yat-Sen University, Guangzhou, China.
authors.forename: Fang
authors.initials: F
authors.lastname: Zheng
authors.forename: Yi-Ji
authors.initials: YJ
authors.lastname: Liao
authors.forename: Mu-Yan
authors.initials: MY
authors.lastname: Cai
authors.forename: Yan-Hui
authors.initials: YH
authors.lastname: Liu
authors.forename: Tian-Hao
authors.initials: TH
authors.lastname: Liu
authors.forename: Shu-Peng
authors.initials: SP
authors.lastname: Chen
authors.forename: Xiu-Wu
authors.initials: XW
authors.lastname: Bian
authors.forename: Xin-Yuan
authors.initials: XY
authors.lastname: Guan
authors.forename: Marie C
authors.initials: MC
authors.lastname: Lin
authors.forename: Yi-Xin
authors.initials: YX
authors.lastname: Zeng
authors.forename: Hsiang-Fu
authors.initials: HF
authors.lastname: Kung
authors.forename: Dan
authors.initials: D
authors.lastname: Xie
mesh_terms: D000818:Animals; D014408:Biomarkers, Tumor / Q000378:metabolism*; D006528:Carcinoma, Hepatocellular / Q000378:metabolism* / Q000473:pathology; D045744:Cell Line, Tumor; D003599:Cytoskeleton / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism*; D000071221:Enhancer of Zeste Homolog 2 Protein; D058750:Epithelial-Mesenchymal Transition; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008113:Liver Neoplasms / Q000378:metabolism* / Q000473:pathology; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D035683:MicroRNAs / Q000378:metabolism*; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009362:Neoplasm Metastasis; D063151:Polycomb Repressive Complex 2; D016016:Proportional Hazards Models; D060888:Real-Time Polymerase Chain Reaction; D014157:Transcription Factors / Q000378:metabolism*; D054460:rho-Associated Kinases / Q000378:metabolism*
chemical_list: D014408:Biomarkers, Tumor; D004268:DNA-Binding Proteins; C509207:MIRN124 microRNA, human; D035683:MicroRNAs; D014157:Transcription Factors; C498409:EZH2 protein, human; D000071221:Enhancer of Zeste Homolog 2 Protein; D063151:Polycomb Repressive Complex 2; C515852:ROCK2 protein, human; D054460:rho-Associated Kinases