Our results suggest that in contrast to the known negative regulation of HIF-2α in most cell types, high PHD3 expression in ccRCC cells maintains elevated HIF-2α expression and that of its target genes, which may enhance kidney cancer aggressiveness.
Specifically, we identify and functionally characterize a coregulatory enhancer cluster, activated by the renal cancer driver HIF2A and an NF-κB-driven lymphoid element, as a mediator of metastasis <i>in vivo</i> We conclude that oncogenic pathways can acquire metastatic phenotypes through cross-lineage co-option of physiologic epigenetic enhancer states.<b>Significance:</b> Renal cancer is associated with significant mortality due to metastasis.
HIFs have been widely studied because of their involvement in cancer, and HIF2α-specific inhibitors are being investigated in clinical trials for the treatment of kidney cancer.
Recent studies have identified small molecule inhibitors of HIF-2α that demonstrate exquisite isoform selectivity, and clinical trials for treatment of HIF-2α-driven kidney cancers are ongoing.
The DNA-damaging agent camptothecin (CPT) and its analogs demonstrate clinical utility for the treatment of advanced solid tumors, and CPT-based nanopharmaceuticals are currently in clinical trials for advanced kidney cancer; however, little is known regarding the effects of CPT on hypoxia-inducible factor-2α (HIF-2α) accumulation and activity in clear cell renal cell carcinoma (ccRCC).
Taken together our data identify Tempol as an agent with potential therapeutic activity targeting expression of HIF2α in VHL-deficient clear cell kidney cancer and illustrate the importance of studying biochemical processes at relevant physiological O2 levels.
Kidney cancers often delete chromosome 3p, spanning the VHL tumor suppressor gene, and chromosome 14q, which presumably harbors ≥ 1 tumor suppressor genes. pVHL inhibits the hypoxia-inducible transcription factor (HIF), and HIF2α is a kidney cancer oncoprotein.