Hepatitis C virus Core protein overcomes all-trans retinoic acid-induced cell growth arrest by inhibiting retinoic acid receptor-β2 expression via DNA methylation

Cancer Lett. 2013 Jul 28;335(2):372-9. doi: 10.1016/j.canlet.2013.02.057. Epub 2013 Mar 6.

Abstract

Aberrant promoter methylation of tumor suppressor genes including retinoic acid receptor-β2 (RAR-β2) is frequently detected in hepatitis C virus (HCV)-associated hepatocellular carcinoma; however, the mechanism and its significance are relatively unknown. Here, we showed that HCV Core induced promoter hypermethylation of RAR-β2 to inhibit its expression via up-regulation of DNA methyltransferases 1 and 3b. Under the condition, all-trans retinoic acid (ATRA) failed to activate p16 expression and thus could not inactivate the Rb-E2F pathway. Accordingly, Core-expressing cells exhibited resistance to ATRA-induced growth inhibition. Taken together, HCV Core antagonizes ATRA, a natural anti-cancer compound, to stimulate cell growth via epigenetic down-regulation of RAR-β2.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Carcinoma, Hepatocellular
  • Cell Line, Tumor
  • Cell Proliferation / drug effects
  • Cyclin-Dependent Kinase Inhibitor p16
  • DNA Methylation*
  • Down-Regulation
  • Gene Expression Regulation, Neoplastic
  • Hep G2 Cells
  • Hepacivirus
  • Hepatitis C Antigens / metabolism*
  • Humans
  • Liver Neoplasms
  • Methyltransferases / biosynthesis
  • Neoplasm Proteins / biosynthesis
  • Promoter Regions, Genetic
  • RNA Interference
  • RNA, Small Interfering
  • Receptors, Retinoic Acid / genetics
  • Receptors, Retinoic Acid / metabolism*
  • Tretinoin / pharmacology*
  • Viral Core Proteins / metabolism*

Substances

  • CDKN2A protein, human
  • Cyclin-Dependent Kinase Inhibitor p16
  • Hepatitis C Antigens
  • Neoplasm Proteins
  • RNA, Small Interfering
  • Receptors, Retinoic Acid
  • Viral Core Proteins
  • nucleocapsid protein, Hepatitis C virus
  • retinoic acid receptor beta
  • Tretinoin
  • Methyltransferases