A High Throughput Screening Campaign for Inhibitors of RGS6 and RGS17

Abstract

G Protein Coupled Receptors (GPCRs) are highly targeted proteins for drug discovery, with over 50% of all drugs on the market targeting these receptors. Regulator of G Protein Signaling (RGS) Proteins regulate the signaling cascade of GPCRs by accelerating the intrinsic GTPase activity of G protein alpha subunits and returning the heterotrimeric G protein to its inactive state. Recently RGS proteins have been implicated as being important in a variety of disease states. RGS17 has been identified as being inappropriately upregulated in both lung and prostate cancer. Knockdown of RGS17 resulted in decreased cell proliferation in vitro, and reduced tumor mass and volume when compared to control when cell lines were injected subcutaneously in nude mice. RGS6 has been shown to play an essential role in doxorubicin mediated cardio toxicity, has been shown to have an important role in anxiolytic and depression phenotypes in mice, and has been implicated as a critical mediator of behavioral and pathological responses to alcohol. Here we present the screening of two RGS proteins (RGS6 and RGS17) using Alpha Screen technology against the NCI Next Diversity Library. Assay robustness was determined for both proteins, with RGS6 Z‐factors above 0.7 and RGS17 Z‐factors above 0.6. Approximately 20,000 compounds were screened against RGS6 resulting in identification of 20 hit compounds, and roughly 60,000 compounds (including the 20K also screened against RGS6) were screened against RGS17 resulting in the identification of 131 hit compounds. Tanimoto similarity analysis was performed on all hits to allow for small scale SAR analysis of confirmed lead compounds. Follow up experiments are under way including dose response analysis and structure based analysis utilizing NMR and molecular modeling.Support or Funding InformationSupported in part by RO1CA160470, in part by OVPRED internal funding initiative RAF‐DLR and in part by a Pre‐Doctoral Fellowship from the American Foundation of Pharmaceutical Education (AFPE)