Cancer cells promote survival through depletion of the von Hippel-Lindau tumor suppressor by protein crosslinking

Oncogene. 2011 Dec 1;30(48):4780-90. doi: 10.1038/onc.2011.183. Epub 2011 May 30.

Abstract

Nuclear factor-κB (NF-κB) and insulin-like growth factor-1 (IGF-1)-mediated signaling is associated with different tumors including renal cell carcinoma. NF-κB- and IGF-1-mediated signaling is found to be inhibited in the presence of wild-type von Hippel-Lindau (VHL) tumor suppresser gene. Therefore, negative regulator of VHL may be a good target for regulating NF-κB and IGF-1R. In this study, we found that VHL, a tumor suppressor protein that downregulates the NF-κB activity and the stability of IGF-1R was depleted by TGase 2 through polymerization via crosslinking and proteasomal degradation in kidney, breast and ovary cancer cell lines. We also found that TGase 2 knockdown promotes hypoxia-inducible factor 1α (HIF-1α) degradation, and thereby decrease HIF-1α transcriptional activity. Importantly, VHL expression was decreased in vivo in TGase-2-transgenic mice, and this was associated with increased NF-κB activity and the levels of expression of IGF-1R, HIF-1α and erythropoietin in kidney tissue. These results suggest a novel mechanism of regulation of the VHL tumor suppressor by TGase 2 that appears to be independent of the known cancer regulatory mechanisms.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Cell Line, Tumor
  • Cell Survival*
  • Down-Regulation
  • GTP-Binding Proteins / antagonists & inhibitors
  • Genes, Tumor Suppressor
  • Humans
  • Insulin-Like Growth Factor I / metabolism
  • Mice
  • Mice, Transgenic
  • Molecular Sequence Data
  • NF-kappa B / metabolism
  • Neoplasms / metabolism
  • Neoplasms / pathology*
  • Protein Glutamine gamma Glutamyltransferase 2
  • Transglutaminases / antagonists & inhibitors
  • Von Hippel-Lindau Tumor Suppressor Protein / chemistry
  • Von Hippel-Lindau Tumor Suppressor Protein / genetics
  • Von Hippel-Lindau Tumor Suppressor Protein / metabolism*

Substances

  • NF-kappa B
  • Insulin-Like Growth Factor I
  • Protein Glutamine gamma Glutamyltransferase 2
  • Transglutaminases
  • Von Hippel-Lindau Tumor Suppressor Protein
  • GTP-Binding Proteins