HIF-1α activation under glucose deprivation plays a central role in the acquisition of anti-apoptosis in human colon cancer cells

Int J Oncol. 2014 Jun;44(6):2077-84. doi: 10.3892/ijo.2014.2367. Epub 2014 Apr 3.

Abstract

A poor vascular network development in a tumor mass leads to poor oxygen and nutrient supply. To adapt to a hypoxic microenvironment, it is well-known that cancer cells activate the transcription factor hypoxia-inducible factor-1α (HIF-1α). HIF-1α plays a central role in hypoxia-induced metabolic switching, anti-apoptosis, angiogenesis and drug resistance. Glucose deprivation, another major stressful microenvironment, protects cancer cells from drug-induced apoptosis. However, the molecular mechanisms by which cancer cells adapt to poor nutrient conditions remain poorly understood. In this study, we focused on HIF-1α, signal transducer and activator of transcription 3 (STAT3) and trans-cription factor 4 (TCF4), which are involved in cell survival, anti-apoptosis and drug resistance. We examined their activities and the relationships among these transcription factors under glucose deprivation. Our results showed that glucose deprivation increased HIF-1α, STAT3 and TCF4 DNA-binding activity, as well as the expression levels of their target genes OCT4, BCL-2 and VEGF. HIF-1α knockdown significantly increased poly(ADP-ribose) polymerase 1 (PARP-1) cleavage at higher levels than STAT3 knockdown under glucose deprivation. Furthermore, HIF-1α knockdown led to a significant decrease in the expression levels of both STAT3 and TCF4, although STAT3 knockdown decreased only HIF-1α expression level. Our data indicated that activation of the HIF-1α signaling pathway under glucose deprivation leads to the acquisition of anti-apoptotic properties in human colon cancer cells, and targeting the HIF-1α signaling pathway may provide an effective avenue for treating cancers resistant to conventional therapy.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Apoptosis
  • Basic Helix-Loop-Helix Leucine Zipper Transcription Factors / genetics
  • Basic Helix-Loop-Helix Leucine Zipper Transcription Factors / metabolism*
  • Cell Line, Tumor
  • Cell Survival / genetics
  • Cell Survival / physiology
  • Colonic Neoplasms / metabolism
  • Colonic Neoplasms / pathology*
  • Gene Expression Regulation, Neoplastic
  • Gene Knockdown Techniques
  • Glucose / metabolism*
  • Humans
  • Hypoxia-Inducible Factor 1, alpha Subunit / genetics
  • Hypoxia-Inducible Factor 1, alpha Subunit / metabolism*
  • STAT3 Transcription Factor / genetics
  • STAT3 Transcription Factor / metabolism*
  • Signal Transduction / genetics
  • Signal Transduction / physiology
  • Transcription Factor 4
  • Transcription Factors / genetics
  • Transcription Factors / metabolism*

Substances

  • Basic Helix-Loop-Helix Leucine Zipper Transcription Factors
  • HIF1A protein, human
  • Hypoxia-Inducible Factor 1, alpha Subunit
  • STAT3 Transcription Factor
  • STAT3 protein, human
  • TCF4 protein, human
  • Transcription Factor 4
  • Transcription Factors
  • Glucose