Inhibition of HIF2alpha is sufficient to suppress pVHL-defective tumor growth.

Biallelic inactivation of the von Hippel-Lindau tumor suppressor gene (VHL) is linked to the development of hereditary (VHL-associated) and sporadic clear-cell renal carcinomas as well as other abnormalities. The VHL gene product, pVHL, is part of an E3 ubiquitin ligase complex that targets the alpha subunits of the heterodimeric transcription factor HIF (hypoxia-inducible factor) for degradation in the presence of oxygen. Here we report that a HIF2alpha variant lacking both of its two prolyl hydroxylation/pVHL-binding sites prevents tumor inhibition by pVHL in a DNA-binding dependent manner. Conversely, downregulation of HIF2alpha with short hairpin RNAs is sufficient to suppress tumor formation by pVHL-defective renal carcinoma cells. These results establish that tumor suppression by pVHL is linked to regulation of HIF target genes.