The tumor-suppressive miR-497-195 cluster targets multiple cell-cycle regulators in hepatocellular carcinoma

PLoS One. 2013;8(3):e60155. doi: 10.1371/journal.pone.0060155. Epub 2013 Mar 27.

Abstract

MicroRNAs (miRNAs) are key post-transcriptional regulators of gene expression and commonly deregulated in carcinogenesis. To explore functionally crucial tumor-suppressive (TS)-miRNAs in hepatocellular carcinoma (HCC), we performed integrative function- and expression-based screenings of TS-miRNAs in six HCC cell lines. The screenings identified seven miRNAs, which showed growth-suppressive activities through the overexpression of each miRNA and were endogenously downregulated in HCC cell lines. Further expression analyses using a large panel of HCC cell lines and primary tumors demonstrated four miRNAs, miR-101, -195, -378 and -497, as candidate TS-miRNAs frequently silenced in HCCs. Among them, two clustered miRNAs miR-195 and miR-497 showed significant growth-suppressive activity with induction of G1 arrest. Comprehensive exploration of their targets using Argonute2-immunoprecipitation-deep-sequencing (Ago2-IP-seq) and genome-wide expression profiling after their overexpression followed by pathway analysis, revealed a significant enrichment of cell cycle regulators. Among the candidates, we successfully identified CCNE1, CDC25A, CCND3, CDK4, and BTRC as direct targets for miR-497 and miR-195. Moreover, target genes frequently upregulated in HCC in a tumor-specific manner, such as CDK6, CCNE1, CDC25A and CDK4, showed an inverse correlation in the expression of miR-195 and miR-497, and their targets. These results suggest the molecular pathway regulating cell cycle progression to be integrally altered by downregulation of miR-195 and miR-497 expression, leading to the aberrant cell proliferation in hepatocarcinogenesis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Carcinoma, Hepatocellular / genetics*
  • Carcinoma, Hepatocellular / pathology
  • Cell Cycle / genetics*
  • Cell Line, Tumor
  • Cell Proliferation
  • Computational Biology
  • Computer Simulation
  • Gene Expression Regulation, Neoplastic
  • Genes, Tumor Suppressor*
  • High-Throughput Nucleotide Sequencing
  • Humans
  • Liver Neoplasms / genetics*
  • Liver Neoplasms / pathology
  • MicroRNAs / genetics*
  • MicroRNAs / metabolism
  • Molecular Sequence Annotation
  • Multigene Family*
  • Reproducibility of Results

Substances

  • MIRN195 microRNA, human
  • MIRN497 microRNA, human
  • MicroRNAs

Associated data

  • GEO/GSE41081

Grants and funding

Grant-in-Aid for Scientific Research (A), (B), (C), and JSPS Fellows, and Scientific Research on Priority Areas and Innovative Areas, and a Global Center of Excellence (GCOE) Program for International Research Center for Molecular Science in Tooth and Bone Diseases from the Ministry of Education, Culture, Sports, Science, and Technology, Japan; a Health and Labour Sciences Research Grant by the Ministry of Health, Labour and Welfare, Japan; a grant from the New Energy and Industrial Technology Development Organization (NEDO). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.