Dual knockdown of N-ras and epiregulin synergistically suppressed the growth of human hepatoma cells

Biochem Biophys Res Commun. 2009 Sep 18;387(2):239-44. doi: 10.1016/j.bbrc.2009.06.128. Epub 2009 Jun 27.

Abstract

Hepatocellular carcinoma (HCC) is a major challenge because of its resistance to conventional cytotoxic chemotherapy and radiotherapy. Multi-targeted therapy might be a new option for HCC treatment. Our previous study showed that N-ras gene was activated in HCC and was inhibited by RNA interference. In the present study, we investigated the alternation of gene expression by microarray in N-Ras-siRNA-treated HepG2 cells. The results revealed that the EREG gene, encoding epiregulin, was dramatically up-regulated in response to silence of N-ras. We speculated that the up-regulation of epiregulin was involved in the compensatory mechanism of N-ras knockdown for cell growth. Therefore, we evaluated whether dual silence of N-ras and epiregulin display a greater suppression of cell growth. The results confirmed that dual knockdown of N-ras and epiregulin synergistically inhibited cell growth. Our results also showed that dual knockdown of N-ras and epiregulin significantly induced cell arrest at G0/G1 phase. Furthermore, Western blot assay showed that dual knockdown of N-ras and epiregulin markedly reduced the phosphorylations of ERK1/2, Akt and Rb, and inhibited the expression of cyclin D1. Our findings imply that multi-targeted silence of oncogenes might be an effective treatment for HCC.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Carcinoma, Hepatocellular / genetics
  • Carcinoma, Hepatocellular / pathology*
  • Carcinoma, Hepatocellular / therapy
  • Cell Line, Tumor
  • Cell Proliferation
  • Cyclin D1 / antagonists & inhibitors
  • Cyclin D1 / biosynthesis
  • Epidermal Growth Factor / genetics*
  • Epiregulin
  • G1 Phase / genetics
  • Gene Knockdown Techniques
  • Gene Silencing
  • Humans
  • Liver Neoplasms / genetics
  • Liver Neoplasms / pathology*
  • Liver Neoplasms / therapy
  • Mitogen-Activated Protein Kinase 1 / antagonists & inhibitors
  • Mitogen-Activated Protein Kinase 1 / biosynthesis
  • Mitogen-Activated Protein Kinase 3 / antagonists & inhibitors
  • Mitogen-Activated Protein Kinase 3 / biosynthesis
  • Proto-Oncogene Proteins c-akt / antagonists & inhibitors
  • Proto-Oncogene Proteins c-akt / biosynthesis
  • Proto-Oncogene Proteins p21(ras) / genetics*
  • RNA, Small Interfering / genetics
  • Resting Phase, Cell Cycle / genetics
  • Retinoblastoma Protein / antagonists & inhibitors
  • Retinoblastoma Protein / biosynthesis

Substances

  • CCND1 protein, human
  • EREG protein, human
  • Epiregulin
  • RNA, Small Interfering
  • Retinoblastoma Protein
  • Cyclin D1
  • Epidermal Growth Factor
  • Proto-Oncogene Proteins c-akt
  • Mitogen-Activated Protein Kinase 1
  • Mitogen-Activated Protein Kinase 3
  • Proto-Oncogene Proteins p21(ras)