title: Loss of miR-122 expression in liver cancer correlates with suppression of the hepatic phenotype and gain of metastatic properties.
abstract: Growing evidence indicates that microRNAs have a significant role in tumor development and may constitute robust biomarkers for cancer diagnosis and prognosis. In this study, we evaluated the clinical and functional relevance of microRNA-122 (miR-122) expression in human hepatocellular carcinoma (HCC). We report that miR-122 is specifically repressed in a subset of primary tumors that are characterized by poor prognosis. We further show that the loss of miR-122 expression in tumor cells segregates with specific gene expression profiles linked to cancer progression, namely the suppression of hepatic phenotype and the acquisition of invasive properties. We identify liver-enriched transcription factors as central regulatory molecules in the gene networks associated with loss of miR-122, and provide evidence suggesting that miR-122 is under the transcriptional control of HNF1A, HNF3A and HNF3B. We further show that loss of miR-122 results in an increase of cell migration and invasion and that restoration of miR-122 reverses this phenotype. In conclusion, miR-122 is a marker of hepatocyte-specific differentiation and an important determinant in the control of cell migration and invasion. From a clinical point of view, our study emphasizes miR-122 as a diagnostic and prognostic marker for HCC progression.
authors.affiliation: Laboratory of Experimental Carcinogenesis, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda 20892-4262, MD, USA.
authors.forename: C
authors.initials: C
authors.lastname: Coulouarn
authors.forename: V M
authors.initials: VM
authors.lastname: Factor
authors.forename: J B
authors.initials: JB
authors.lastname: Andersen
authors.forename: M E
authors.initials: ME
authors.lastname: Durkin
authors.forename: S S
authors.initials: SS
authors.lastname: Thorgeirsson
mesh_terms: D006528:Carcinoma, Hepatocellular / Q000235:genetics* / Q000401:mortality / Q000473:pathology; D045744:Cell Line, Tumor; D020869:Gene Expression Profiling; D006801:Humans; D008113:Liver Neoplasms / Q000235:genetics* / Q000401:mortality / Q000473:pathology; D035683:MicroRNAs / Q000032:analysis / Q000502:physiology*; D009361:Neoplasm Invasiveness; D009362:Neoplasm Metastasis; D010641:Phenotype; D011379:Prognosis
chemical_list: C531907:MIRN122 microRNA, human; D035683:MicroRNAs