The Most Common VHL Point Mutation R167Q in Hereditary VHL Disease Interferes with Cell Plasticity Regulation

SIMPLE SUMMARY: Von Hippel–Lindau (VHL) disease is characterized by mutations in the VHL gene, which can induce numerous benign and malignant tumors in different organs, as well as highly vascularized clear cell renal cell carcinomas (ccRCCs). The aim of this study was to examine whether the VHL-R167Q mutation, which is associated with a high risk of developing ccRCC (type 2B VHL disease), could impact the plasticity of renal carcinoma cells. Our transcriptomic results show that VHL-R167Q regulates hypoxia-, plasticity-, and stemness-related genes. Moreover, analysis in a ccRCCs TCGA dataset highlighted that a number of genes regulated by hypoxia and related to stemness in VHL-R167Q-expressing tumors are associated with a poor survival in ccRCCs patients. ABSTRACT: Von Hippel–Lindau disease (VHL) is a rare hereditary syndrome due to mutations of the VHL tumor suppressor gene. Patients harboring the R167Q mutation of the VHL gene have a high risk of developing ccRCCs. We asked whether the R167Q mutation with critical aspects of pseudo-hypoxia interferes with tumor plasticity. For this purpose, we used wild-type VHL (WT-VHL) and VHL-R167Q reconstituted cells. We showed that WT-VHL and VHL-R167Q expression had a similar effect on cell morphology and colony formation. However, cells transfected with VHL-R167Q display an intermediate, HIF2-dependent, epithelial–mesenchymal phenotype. Using RNA sequencing, we showed that this mutation upregulates the expression of genes involved in the hypoxia pathway, indicating that such mutation is conferring an enhanced pseudo-hypoxic state. Importantly, this hypoxic state correlates with the induction of genes belonging to epithelial–mesenchymal transition (EMT) and stemness pathways, as revealed by GSEA TCGA analysis. Moreover, among these deregulated genes, we identified nine genes specifically associated with a poor patient survival in the TCGA KIRC dataset. Together, these observations support the hypothesis that a discrete VHL point mutation interferes with tumor plasticity and may impact cell behavior by exacerbating phenotypic switching. A better understanding of the role of this mutation might guide the search for more effective treatments to combat ccRCCs.