title: MiR-222 overexpression confers cell migratory advantages in hepatocellular carcinoma through enhancing AKT signaling.
abstract: OBJECTIVE
  This study aims to profile the expressions of 156 microRNAs (miRNA) in hepatocellular carcinoma (HCC) and to characterize the functions of miR-222, the most significantly upregulated candidate identified.
  
  
  METHODS
  miRNA expression profile in HCC tumors, matching adjacent cirrhotic livers, and cell lines was conducted using quantitative PCR. Common miR-222 upregulations were further validated in a larger cohort of tumors. The functional effects of miR-222 inhibition on HCC cell lines were examined. The downstream modulated pathways and target of miR-222 were investigated by coupling gene expression profiling and pathway analysis, and by in silico prediction, respectively. Luciferase reporter assay was done to confirm target interaction.
  
  
  RESULTS
  We identified a 40-miRNA signature that could discriminate tumors from adjacent cirrhotic liver tissue, and further corroborated common miR-222 overexpression in tumors relative to its premalignant counterpart (55.3%; P < 0.0001). Increased miR-222 expression correlated significantly with advanced stage HCC and with the shorter disease-free survival of patients (P < or = 0.01). Inhibition of miR-222 in Hep3B and HKCI-9 significantly retarded cell motility (P < 0.05). Further investigations suggested that AKT signaling was the major pathway influenced by miR-222. A consistent reduction of AKT phosphorylation in Hep3B and HKCI-9 was shown following miR-222 suppression. The protein phosphatase 2A subunit B (PPP2R2A) was predicted as a putative miR-222 target in silico. We found that miR-222 inhibition could augment the tumor protein level and restore luciferase activity in reporter construct containing the PPP2R2A 3' untranslated region (P = 0.0066).
  
  
  CONCLUSIONS
  Our study showed that miR-222 overexpression is common in HCC and could confer metastatic potentials in HCC cells, possibly through activating AKT signaling.
authors.affiliation: Department of Anatomical and Cellular Pathology, The Chinese University of Hong Kong, Shatin, Hong Kong, China.
authors.forename: Queenie W-L
authors.initials: QW
authors.lastname: Wong
authors.forename: Arthur K-K
authors.initials: AK
authors.lastname: Ching
authors.forename: Anthony W-H
authors.initials: AW
authors.lastname: Chan
authors.forename: Kwong-Wai
authors.initials: KW
authors.lastname: Choy
authors.forename: Ka-Fai
authors.initials: KF
authors.lastname: To
authors.forename: Paul B-S
authors.initials: PB
authors.lastname: Lai
authors.forename: Nathalie
authors.initials: N
authors.lastname: Wong
mesh_terms: D006528:Carcinoma, Hepatocellular / Q000235:genetics* / Q000473:pathology; D002465:Cell Movement; D018450:Disease Progression; D006801:Humans; D008103:Liver Cirrhosis / Q000150:complications / Q000235:genetics; D008113:Liver Neoplasms / Q000235:genetics* / Q000473:pathology; D035683:MicroRNAs / Q000378:metabolism*; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism*; D015398:Signal Transduction / Q000235:genetics; D015854:Up-Regulation
chemical_list: D035683:MicroRNAs; D051057:Proto-Oncogene Proteins c-akt; C525710:MIR222, human