Silencing of Hypoxia-Inducible factor-1β Induces Anti-Tumor Effects in Hepatoma Cell Lines Under Tumor Hypoxia

PLoS One. 2014 Jul 28;9(7):e103304. doi: 10.1371/journal.pone.0103304. eCollection 2014.

Abstract

Dimerization of hypoxia-inducible factor-1 beta (HIF-1β) [aryl hydrocarbon receptor nuclear translocator (ARNT)] with HIF-1α is involved in various aspects of cancer biology, including proliferation and survival under hypoxic conditions. We investigated the in vitro mechanism by which silencing of HIF-1β leads to the suppression of tumor cell growth and cellular functions. Various hepatocellular carcinoma (HCC) cell lines (Huh-7, Hep3B, and HepG2) were transfected with small interfering RNA (siRNA) against HIF-1β (siHIF-1β) and cultured under hypoxic conditions (1% O2 for 24 h). The expression levels of HIF-1β, HIF-1α, and growth factors were examined by immunoblotting. Tumor growth was measured using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, and tumor activity was measured by terminal deoxynucleotidyl transferase dUTP nick end labeling, tumor cell invasion, and migration assays. Under hypoxic conditions, silencing of HIF-1β expression suppressed tumor cell growth and regulated the expression of tumor growth-related factors, such as vascular endothelial growth factor, epidermal growth factor, and hepatocyte growth factor. Suppression of tumor cell invasion and migration was also demonstrated in HIF-1β-silenced HCC cell lines. Silencing of HIF-1β expression may induce anti-tumor effects under hypoxic conditions in HCC cell lines.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Apoptosis / genetics
  • Aryl Hydrocarbon Receptor Nuclear Translocator / genetics*
  • Aryl Hydrocarbon Receptor Nuclear Translocator / metabolism
  • Carcinoma, Hepatocellular / genetics
  • Carcinoma, Hepatocellular / metabolism
  • Carcinoma, Hepatocellular / pathology
  • Cell Hypoxia
  • Cell Line, Tumor
  • Cell Movement / genetics
  • Cell Proliferation / genetics*
  • Gene Expression Regulation, Neoplastic*
  • Hep G2 Cells
  • Humans
  • Hypoxia-Inducible Factor 1, alpha Subunit / genetics
  • Hypoxia-Inducible Factor 1, alpha Subunit / metabolism
  • Immunoblotting
  • Liver Neoplasms / genetics
  • Liver Neoplasms / metabolism
  • Liver Neoplasms / pathology
  • RNA Interference*
  • Reverse Transcriptase Polymerase Chain Reaction

Substances

  • Hypoxia-Inducible Factor 1, alpha Subunit
  • Aryl Hydrocarbon Receptor Nuclear Translocator

Grant support

This research was supported by student research project funded by Yonsei University College of Medicine (2010–2011). This study was also supported by a faculty research grant of Yonsei University College of Medicine for 2012 (6-2012-0008). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.