HIF-2α promotes hypoxic cell proliferation by enhancing c-Myc transcriptional activity

Summary HIF-2α promotes von Hippel-Lindau ( VHL )-deficient renal clear cell carcinoma (RCC) tumorigenesis, while HIF-1α inhibits RCC growth. As HIF-1α antagonizes c-Myc function, we hypothesized that HIF-2α might enhance c-Myc activity. We demonstrate here that HIF-2α promotes cell-cycle progression in hypoxic RCCs and multiple other cell lines. This correlates with enhanced c-Myc promoter binding, transcriptional effects on both activated and repressed target genes, and interactions with Sp1, Miz1, and Max. Finally, HIF-2α augments c-Myc transformation of primary mouse embryo fibroblasts (MEFs). Enhanced c-Myc activity likely contributes to HIF-2α-mediated neoplastic progression following loss of the VHL tumor suppressor and influences the behavior of hypoxic tumor cells.