SHARPIN regulates the development of clear cell renal cell carcinoma by promoting von Hippel-Lindau protein ubiquitination and degradation

SHANK-associated RH domain interacting protein (SHARPIN) plays an important role in carcinogenesis, as well as inflammation and immunity. Our study explored the effects and underlying mechanisms of SHARPIN in clear cell renal cell carcinoma (ccRCC). By analyzing The Cancer Genome Atlas database, we found that upregulated SHARPIN in patients with ccRCC led to a poor prognosis. Semiquantitative immunohistochemical analysis of clinical samples was carried out arid the results suggested the positive association between SHARPIN and hypoxia-induced factor-2 alpha (HIF-2 alpha). Von Hippel-Lindau protein (pVHL) is a tumor suppressor that contributes to degrading HIF 2 alpha. Mechanically, SHARPIN promoted the ubiquitination and proteasomal degradation of pVHL, resulting in the sustained activation of HIF-2 alpha. The alpha and beta domains of pVHL and ubiquitin-like domain of SHARPIN are required for the interaction. The knockdown of SHARPIN effectively inhibited acquired sorafenib resistance in ccRCC cell lines and tumor growth in xenograft models. In conclusion, our work reveals a novel posttranslational regulation of SHARPIN on pVHL, indicating that SHARPIN could be a potential target for ccRCC treatment.

Automated summary

SHARPIN upregulation in ccRCC patients leads to poor prognosis and is positively associated with HIF-2α; SHARPIN promotes the ubiquitination and degradation of pVHL to sustain HIF-2α activation.