Rescuing the Function of Missense-Mutated Tumor Suppressor VHL using Stabilizing Small Molecules

Somatic mutations in the VHL gene, coupled with VHL loss of heterozygosity, drive sporadic clear cell renal cell carcinoma (ccRCC). From structural considerations, we hypothesized that certain mutations in the VHL gene thermodynamically destabilize the folded protein product; these mutations would increase the ratio of unfolded:folded pVHL, and thus cause loss of function. To test this, we used computational structure-based screening followed by biophysical characterization and cellular assays to identify small molecules that bind to the folded (native) conformation of pVHL and stabilize it. These studies led to creation of an agent, CP4.29, that stabilizes the native folded structure of mutant pVHL: this in turn restores wild-type pVHL activities to cells that harbor mutant VHL. These compounds may serve as starting points for further development into an unprecedented new class of kidney cancer drugs. The approach described herein may also serve as a blueprint for developing agents to correct destabilized mutations underlying other human diseases.