Abstract IA003: Chemoproteomic discovery of a covalent allosteric inhibitor of WRN helicase

Abstract The WRN helicase serves as a key target in the treatment of cancers characterized by microsatellite instability (MSI) because it plays a crucial role in resolving harmful non-canonical DNA structures that arise in cells with defective mismatch repair systems. Despite the critical functions of human DNA and RNA helicases, no drugs targeting these enzymes have been approved, largely due to the difficulties in identifying potent and selective inhibitors. In this study, we present the chemoproteomics-based identification of a clinical-stage, covalent allosteric inhibitor of WRN, VVD-133214. This inhibitor specifically interacts with a cysteine residue (C727) within the helicase domain, which undergoes inter-domain movement during the DNA unwinding process. VVD-133214 reacts with the WRN protein in a nucleotide cooperative manner, promoting stable, compact structures that impede the enzyme's dynamic flexibility essential for its helicase activity. Inhibition of WRN by VVD-133214 leads to extensive double-stranded DNA breaks, nuclear enlargement, and ultimately cell death, specifically in MSI-high cells but not in microsatellite stable cells. The inhibitor demonstrated good tolerance in mice and significant tumor reduction in various MSI-high colorectal cancer cell lines and patient-derived xenograft models. Our findings highlight an allosteric strategy to inhibit WRN function that avoids interference from the endogenous ATP cofactor in cancer cells and positions VVD-133214 as a promising therapeutic candidate for patients with MSI-high cancers. Citation Format: Matthew P. Patricelli, Kristen A. Baltgalvis, Kelsey N. Lamb, Kent T. Symons, Chu-Chiao Wu, Melissa A. Hoffman, Aaron N. Snead, Xiaodan Song, Thomas Glaza, Shota Kikuchi, Jason C. Green, Donald C. Rogness, Betty Lam, Maria E. Rodriguez-Aguirre, David R. Woody, Christie L. Eissler, Socorro Rodilles, Seth M .Negron, Steffen M. Bernard, Eileen Tran, Jonathan Pollock, Ali Tabatabaei, Victor Contreras, Heather N Williams, Martha K. Pastuszka, John J. Sigler, Piergiorgio Pettazzoni, Markus G. Rudolph, Moritz Classen, Doris Brugger, Christopher Claiborne, Jean-Marc Plancher, Isabel Cuartas, Joan Seoane, Laurence E. Burgess, Robert T. Abraham, David S. Weinstein, Gabriel M. Simon, Todd M. Kinsella. Chemoproteomic discovery of a covalent allosteric inhibitor of WRN helicase [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Expanding and Translating Cancer Synthetic Vulnerabilities; 2024 Jun 10-13; Montreal, Quebec, Canada. Philadelphia (PA): AACR; Mol Cancer Ther 2024;23(6 Suppl):Abstract nr IA003.