Hypoxia-triggered ERRα acetylation enhanced its oncogenic role and promoted progression of renal cell carcinoma by coordinating autophagosome-lysosome fusion.

Abstract

Estrogen-related receptor α (ERRα) is dysregulated in many types of cancer and exhibits oncogenic activity by promoting tumorigenesis and metastasis of cancer cells. However, its defined role in renal cell carcinoma (RCC) has not been fully elucidated. To reveal the biological function of ERRα and determine the underlying regulatory mechanism in RCC, the quantitative proteomics analysis and mechanism investigation were conducted. The results demonstrated that ERRα promoted the proliferation and tumorigenesis of RCC cells by maintaining lysosome-dependent autophagy flux. ERRα inhibition impaired the transcriptional expression of LAMP2 and VAMP8 and blocked the fusion of autophagosomes with lysosomes, causing the impairment of the autophagy-lysosome pathway and tumor repression in RCC. Moreover, VHL mutant-induced hyperactive hypoxia signaling in RCC triggered p300/CBP-mediated acetylation at the DNA-binding domain of ERRα, and this acetylation promoted its affinity toward targeting DNA and Parkin-mediated ubiquitination and proteasome-dependent degradation. This regulatory model enhanced ERRα transactivation on the expression of LAMP2 and VAMP8, which then maintained autophagy flux and RCC progression. Pharmaceutical inhibition on ERRα acetylation-mediated autophagy-lysosome pathway led to growth repression and sunitinib sensitivity of RCC cells. Taken together, this study uncovered a novel regulatory mechanism of acetylation contributing to the transcriptional performance and the oncogenic role of ERRα in RCC progression by modulating the autophagy-lysosome pathway. These findings might provide a novel approach for the clinical diagnosis and resolution of sunitinib resistance of RCC.