Di-Ras2 Promotes Renal Cell Carcinoma Formation by Activating the MAPK Pathway in the Absence of VHL

Abstract

Clear cell renal cell carcinoma (ccRCC) is one of the most common and lethal human urological malignancies in the world. The pathological drivers for ccRCC are still poorly understood. One of them is the Ras family of small GTPases that function as \"molecular switches\" in many diseases including ccRCC. Among them, Di-Ras2 encodes a 26-kDa GTPase that shares 60% homology to Ras and Rap. Yet little is known about the biological function(s) of Di-Ras2. In this study, we found that Di-Ras2 was upregulated in ccRCC, and promoted the proliferation, migration and invasion of human ccRCC cells in the absence of von Hippel-Lindau (VHL). Mechanistically, Di-Ras2 induces and regulates ccRCC formation by modulating phosphorylation of the downstream effectors and activating the MAPK signaling pathway. Moreover, Di-Ras2 interacts with E3 ubiquitin ligase, VHL, which facilitates the ubiquitination and degradation of Di-Ras2. Together, these results indicate a potential function of Di-Ras2 as an oncogene and biomarker in ccRCC, and these data provide a new perspective of the relationship between VHL and the MAPK pathway in ccRCC tumorigenesis.