Induction of transcription factor CEBP homology protein mediates hypoglycaemia-induced necrotic cell death in human neuroblastoma cells

J Neurochem. 2006 Nov;99(3):952-64. doi: 10.1111/j.1471-4159.2006.04135.x. Epub 2006 Aug 29.

Abstract

Oxygen and glucose deprivation are direct consequences of tissue ischaemia. We explored the interaction of hypoxia and hypoglycaemia on cell survival and gene expression in the absence of glutamatergic signalling using human SH-SY5Y neuroblastoma cells as a model. In agreement with previous investigations in non-neural cells, prolonged hypoxia (0.5% O(2)) failed to induce significant cell death in this system. In contrast, exposure to hypoglycaemia induced significant necrotic cell death (> 80% after 72 h). Interestingly, hypoglycaemia-induced cell death was completely abrogated by simultaneous exposure to hypoxia, suggesting strong cytoprotective effects of hypoxia. Subsequent microarray analysis of the underlying transcriptional responses revealed that the transcription factor CEBP homology protein (CHOP) was strongly induced by hypoglycaemia, and suppressed by simultaneous hypoxia. RNA interference against CHOP significantly protected cells from glucose deprivation-induced cell death. Hypoxia-induced vascular endothelial growth factor (VEGF) activation also protected cells against hypoglycaemia-induced cell death, but VEGF failed to modify hypoglycaemia-induced CHOP induction. Our data suggest that hypoglycaemia-induced necrotic cell death of neuroblastoma cells is an active process mediated via the induction of the transcription factor CHOP, and that hypoxia counteracts this cell death via at least two distinct mechanisms: repression of CHOP and induction of VEGF.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Apoptosis / genetics
  • Apoptosis / physiology
  • Blotting, Western
  • Brain Neoplasms / pathology*
  • CCAAT-Enhancer-Binding Proteins / biosynthesis*
  • CCAAT-Enhancer-Binding Proteins / genetics
  • CCAAT-Enhancer-Binding Proteins / physiology
  • Caspase 3 / metabolism
  • Cell Death
  • Cell Line, Tumor
  • Fluorescent Dyes
  • Glucose / deficiency
  • Humans
  • Hypoglycemia / metabolism*
  • Hypoxia / pathology
  • Necrosis
  • Neuroblastoma / pathology*
  • Oligonucleotide Array Sequence Analysis
  • Signal Transduction / physiology
  • Transfection
  • Vascular Endothelial Growth Factor A / physiology

Substances

  • CCAAT-Enhancer-Binding Proteins
  • Fluorescent Dyes
  • Vascular Endothelial Growth Factor A
  • Caspase 3
  • Glucose