The von Hippel-Lindau gene product inhibits renal cell apoptosis via Bcl-2-dependent pathways

J Biol Chem. 2001 Nov 2;276(44):40599-605. doi: 10.1074/jbc.M103424200. Epub 2001 Aug 20.

Abstract

Previous studies have reported a protective role for the von Hippel-Lindau (VHL) gene products against pro-apoptotic cellular stresses, but the mechanisms remain unclear. In this study, we examined the role of VHL in renal cells subjected to chemical hypoxia, using four VHL-negative and two VHL-positive cell lines. VHL-negative renal carcinoma cells underwent apoptosis following chemical hypoxia (short-term glucose deprivation and antimycin treatment), as evidenced by morphologic changes and internucleosomal DNA cleavage. Reintroduction of VHL expression prevented this apoptosis. VHL-negative cells displayed a significant (greater than 5-fold) activation of caspase 9 and release of cytochrome c into the cytosol following chemical hypoxia. In contrast, VHL-positive cells showed minimal caspase 9 activation, and absence of cytochrome c release under the same conditions. Caspase 8 was only minimally activated in both VHL-negative and -positive cells. In addition, VHL-positive cells displayed a striking up-regulation of Bcl-2 expression (5-fold) following chemical hypoxia. Antisense oligonucleotides to Bcl-2 significantly down-regulated Bcl-2 protein expression in VHL-positive cells and rendered them sensitive to apoptosis. Overexpression of Bcl-2 in VHL-negative cells conferred resistance to apoptosis. Our results suggest that VHL protects renal cells from apoptosis via Bcl-2-dependent pathways.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Apoptosis / physiology*
  • Base Sequence
  • Carcinoma, Renal Cell / pathology
  • Cell Hypoxia
  • Cytochrome c Group / metabolism
  • DNA Primers
  • Kidney / cytology*
  • Kidney Neoplasms / pathology
  • Ligases / genetics
  • Ligases / physiology*
  • Proto-Oncogene Proteins c-bcl-2 / physiology*
  • Tumor Cells, Cultured
  • Tumor Suppressor Proteins*
  • Ubiquitin-Protein Ligases*
  • Von Hippel-Lindau Tumor Suppressor Protein
  • von Hippel-Lindau Disease / genetics*

Substances

  • Cytochrome c Group
  • DNA Primers
  • Proto-Oncogene Proteins c-bcl-2
  • Tumor Suppressor Proteins
  • Ubiquitin-Protein Ligases
  • Von Hippel-Lindau Tumor Suppressor Protein
  • Ligases