Up-regulation of Hypoxia-Inducible Factors HIF-1alpha and HIF-2alpha Under Normoxic Conditions in Renal Carcinoma Cells by Von Hippel-Lindau Tumor Suppressor Gene Loss of Function

Oncogene. 2000 Nov 16;19(48):5435-43. doi: 10.1038/sj.onc.1203938.

Abstract

Hypoxia induces transcription of a range of physiologically important genes including erythropoietin and vascular endothelial growth factor. The transcriptional activation is mediated by the hypoxia-inducible factor-1 (HIF-1), a heterodimeric member of the basic helix-loop-helix PAS family, composed of alpha and beta subunits. HIF-1alpha shares 48 per cent identity with the recently identified HIF-2alpha protein that is also stimulated by hypoxia. In a previous study of hemangioblastomas, the most frequent manifestation of hereditary von Hippel-Lindau disease (VHL), we found elevated levels of vascular endothelial growth factor and HIF-2alpha mRNA in stromal cells of the tumors. Mutations of the VHL tumor suppressor gene are associated with a variety of tumors such as renal clear cell carcinomas (RCC). In this study, we analysed the expression of the hypoxia-inducible factors HIF-1alpha and HIF-2alpha in a range of VHL wildtype and VHL deficient RCC cell lines. In the presence of functional VHL protein, HIF-1alpha mRNA levels are elevated, whereas HIF-2alpha mRNA expression is increased only in cells lacking a functional VHL gene product. On the protein levels, however, in VHL deficient cell lines, both HIF-alpha subunits are constitutively expressed, whereas re-introduction of a functional VHL gene restores the instability of HIF-1alpha and HIF-2alpha proteins under normoxic conditions. Moreover, immunohistochemical analyses of RCCs and hemangioblastomas demonstrate up-regulation of HIF-1alpha and HIF-2alpha in the tumor cells. The data presented here provide evidence for a role of the VHL protein in regulation of angiogenesis and erythropoiesis mediated by the HIF-1alpha and HIF-2alpha proteins.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Basic Helix-Loop-Helix Transcription Factors
  • Carcinoma, Renal Cell / genetics
  • Carcinoma, Renal Cell / metabolism*
  • Cerebellum / metabolism
  • Cerebellum / physiology
  • DNA-Binding Proteins / biosynthesis*
  • DNA-Binding Proteins / genetics
  • Endothelial Growth Factors / biosynthesis
  • Endothelial Growth Factors / genetics
  • Genes, Tumor Suppressor / physiology*
  • Glucose Transporter Type 1
  • Hemangioblastoma / genetics
  • Hemangioblastoma / metabolism
  • Humans
  • Hypoxia-Inducible Factor 1
  • Hypoxia-Inducible Factor 1, alpha Subunit
  • Immunohistochemistry
  • Kidney Neoplasms / genetics*
  • Kidney Neoplasms / metabolism
  • Ligases*
  • Lymphokines / biosynthesis
  • Lymphokines / genetics
  • Monosaccharide Transport Proteins / biosynthesis
  • Monosaccharide Transport Proteins / genetics
  • Mutation
  • Nuclear Proteins / biosynthesis*
  • Nuclear Proteins / genetics
  • Oxygen / metabolism*
  • Polymerase Chain Reaction
  • Proteins / genetics*
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Trans-Activators / biosynthesis*
  • Trans-Activators / genetics
  • Transcription Factors*
  • Tumor Cells, Cultured
  • Tumor Suppressor Proteins*
  • Ubiquitin-Protein Ligases*
  • Up-Regulation
  • Vascular Endothelial Growth Factor A
  • Vascular Endothelial Growth Factors
  • Von Hippel-Lindau Tumor Suppressor Protein
  • von Hippel-Lindau Disease / genetics

Substances

  • Basic Helix-Loop-Helix Transcription Factors
  • DNA-Binding Proteins
  • Endothelial Growth Factors
  • Glucose Transporter Type 1
  • HIF1A protein, human
  • Hypoxia-Inducible Factor 1
  • Hypoxia-Inducible Factor 1, alpha Subunit
  • Lymphokines
  • Monosaccharide Transport Proteins
  • Nuclear Proteins
  • Proteins
  • RNA, Messenger
  • SLC2A1 protein, human
  • Trans-Activators
  • Transcription Factors
  • Tumor Suppressor Proteins
  • Vascular Endothelial Growth Factor A
  • Vascular Endothelial Growth Factors
  • endothelial PAS domain-containing protein 1
  • Ubiquitin-Protein Ligases
  • Von Hippel-Lindau Tumor Suppressor Protein
  • Ligases
  • VHL protein, human
  • Oxygen