title: A functional screening identifies five microRNAs controlling glypican-3: role of miR-1271 down-regulation in hepatocellular carcinoma.
abstract: Hepatocellular carcinoma (HCC) is the major primary liver cancer. Glypican-3 (GPC3), one of the most abnormally expressed genes in HCC, participates in liver carcinogenesis. Based on data showing that GPC3 expression is posttranscriptionally altered in HCC cells compared to primary hepatocytes, we investigated the implication of microRNAs (miRNAs) in GPC3 overexpression and HCC. To identify GPC3-regulating miRNAs, we developed a dual-fluorescence FunREG (functional, integrated, and quantitative method to measure posttranscriptional regulations) system that allowed us to screen a library of 876 individual miRNAs. Expression of candidate miRNAs and that of GPC3 messenger RNA (mRNA) was measured in 21 nontumoral liver and 112 HCC samples. We then characterized the phenotypic consequences of modulating expression of one candidate miRNA in HuH7 cells and deciphered the molecular mechanism by which this miRNA controls the posttranscriptional regulation of GPC3. We identified five miRNAs targeting GPC3 3'-untranslated region (UTR) and regulating its expression about the 876 tested. Whereas miR-96 and its paralog miR-1271 repressed GPC3 expression, miR-129-1-3p, miR-1291, and miR-1303 had an inducible effect. We report that miR-1271 expression is down-regulated in HCC tumor samples and inversely correlates with GPC3 mRNA expression in a particular subgroup of HCC. We also report that miR-1271 inhibits the growth of HCC cells in a GPC3-dependent manner and induces cell death.
  
  
  CONCLUSIONS
  Using a functional screen, we found that miR-96, miR-129-1-3p, miR-1271, miR-1291, and miR-1303 differentially control GPC3 expression in HCC cells. In a subgroup of HCC, the up-regulation of GPC3 was associated with a concomitant down-regulation of its repressor miR-1271. Therefore, we propose that GPC3 overexpression and its associated oncogenic effects are linked to the down-regulation of miR-1271 in HCC.
authors.affiliation: University Bordeaux, Physiopathologie du cancer du foie, U1053, F-33000 Bordeaux, France.
authors.forename: Marion
authors.initials: M
authors.lastname: Maurel
authors.forename: Sandra
authors.initials: S
authors.lastname: Jalvy
authors.forename: Yannick
authors.initials: Y
authors.lastname: Ladeiro
authors.forename: Chantal
authors.initials: C
authors.lastname: Combe
authors.forename: Laetitia
authors.initials: L
authors.lastname: Vachet
authors.forename: Francis
authors.initials: F
authors.lastname: Sagliocco
authors.forename: Paulette
authors.initials: P
authors.lastname: Bioulac-Sage
authors.forename: Vincent
authors.initials: V
authors.lastname: Pitard
authors.forename: Hélène
authors.initials: H
authors.lastname: Jacquemin-Sablon
authors.forename: Jessica
authors.initials: J
authors.lastname: Zucman-Rossi
authors.forename: Benoît
authors.initials: B
authors.lastname: Laloo
authors.forename: Christophe F
authors.initials: CF
authors.lastname: Grosset
mesh_terms: D020413:3' Untranslated Regions; D006528:Carcinoma, Hepatocellular / Q000378:metabolism*; D045744:Cell Line, Tumor; D015972:Gene Expression Regulation, Neoplastic; D053673:Glypicans / Q000378:metabolism*; D022781:Hepatocytes / Q000378:metabolism; D006801:Humans; D008113:Liver Neoplasms / Q000378:metabolism*; D035683:MicroRNAs / Q000378:metabolism*; D012323:RNA Processing, Post-Transcriptional
chemical_list: D020413:3' Untranslated Regions; C105937:GPC3 protein, human; D053673:Glypicans; C556309:MIRN1271 microRNA, human; D035683:MicroRNAs