USP10 regulates HIF2α stability by deubiquitinating HIF2α regardless of VHL status in kidney cancer.

BACKGROUND: Hypoxia inducible factor 2α (HIF2α) is a major oncogenic driver in clear cell renal cell carcinoma (ccRCC). HIF2α is upregulated by von Hippel-Lindau (VHL) gene loss-of-function mutations in ccRCC. Deubiquitinating enzymes (DUBs) have emerged as key regulators of oncoprotein stability, but which DUBs sustain HIF2α accumulation in ccRCC remains unknown. Our study sought to systematically identify DUBs that stabilize HIF2α regardless of VHL status. METHODS: We selected three ccRCC cell lines with distinct VHL gene statuses, and 15 DUB inhibitors were applied to screen for DUBs that regulate the degradation of the HIF2α protein in ccRCC regardless of VHL gene status. Coimmunoprecipitation (Co-IP) and mass spectrometry (MS) were used to verify the interactions between DUBs and the HIF2α protein. RESULTS: In our study, the PR-619 inhibitor caused a decrease in the HIF2α protein level in 786-O, OS-RC-2, and SW839 cells, and MG132 treatment increased HIF2α protein expression after PR-619 treatment. Furthermore, the MS, Co-IP and Western blotting results revealed that ubiquitin-specific peptidase 10 (USP10) is a DUB that binds to HIF2α and that depletion of USP10 leads to HIF2α downregulation through promotion of HIF2α ubiquitination. We also confirmed that USP10 expression was upregulated in kidney cancer and had a positive correlation with HIF2α expression in RCC patient samples. CONCLUSIONS: Our results suggest that USP10 promotes HIF2α stability.