Inhibition of c-FLIP expression by miR-512-3p contributes to taxol-induced apoptosis in hepatocellular carcinoma cells

Oncol Rep. 2010 May;23(5):1457-62. doi: 10.3892/or_00000784.

Abstract

Dysregulation of the antiapoptotic protein cellular FLICE-like inhibitory protein (c-FLIP) has been proven to be associated with tumorigenesis and progress of most human cancers. However, its aberrant expression is poorly elucidated. MicroRNAs (miRNAs) are small non-coding RNAs that are involved in tumorigenesis through negatively regulating gene expression. Our study disclosed that c-FLIP was overexpressed in HepG2 hepatocellular carcinoma cells and down-regulation of c-FLIP enhanced taxol-induced apoptosis. Taxol induction significantly decreased the protein level of c-FLIP. While no decrease in c-FLIP mRNA level was observed, indicating taxol decreased c-FLIP expression through a post-transcriptional mechanism. miR-512-3p was a predicted suppressor of c-FLIP and exhibited an opposite expression manner to c-FLIP before and after taxol induction. Luciferase report assay demonstrated miR-512-3p negatively regulated c-FLIP expression via a conserved miRNA-binding site in 3' untranslated region (3'UTR) of c-FLIP. The decrease of c-FLIP protein due to transfection of miR-512-3p further validated the inhibitory effect of miR-512-3p on c-FLIP. Additional transfection of miR-512-3p remarkably promoted taxol-induced apoptosis, confirming its involvement in apoptosis. In summary, our study disclosed a novel regulatory mechanism that down-regulation of c-FLIP by miR-512-3p contributed to taxol-induced apoptosis. Importantly, the pivotal role of miR-512-3p in determining c-FLIP abundance helps to broaden the implications for cancer therapy by developing small molecules to directly target c-FLIP at mRNA level.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 3' Untranslated Regions
  • Antineoplastic Agents, Phytogenic / pharmacology*
  • Apoptosis / drug effects*
  • Apoptosis / genetics
  • Base Sequence
  • Binding Sites
  • CASP8 and FADD-Like Apoptosis Regulating Protein / genetics
  • CASP8 and FADD-Like Apoptosis Regulating Protein / metabolism*
  • Carcinoma, Hepatocellular / genetics
  • Carcinoma, Hepatocellular / metabolism
  • Carcinoma, Hepatocellular / pathology*
  • Computational Biology
  • Down-Regulation
  • Gene Expression Regulation, Neoplastic
  • Hep G2 Cells
  • Humans
  • Liver Neoplasms / genetics
  • Liver Neoplasms / metabolism
  • Liver Neoplasms / pathology*
  • MicroRNAs / metabolism*
  • Molecular Sequence Data
  • Paclitaxel / pharmacology*
  • RNA Interference
  • RNA, Messenger / metabolism
  • Time Factors
  • Transfection

Substances

  • 3' Untranslated Regions
  • Antineoplastic Agents, Phytogenic
  • CASP8 and FADD-Like Apoptosis Regulating Protein
  • CFLAR protein, human
  • MicroRNAs
  • RNA, Messenger
  • Paclitaxel