Discovery and Characterization of BAY-805, a Potent and Selective Inhibitor of Ubiquitin-Specific Protease USP21
Fabian Göricke, Victoria Vu, Leanna Smith, U. Scheib, Raphael Böhm, Namık Akkılıç, Gerd Wohlfahrt, Jörg Weiske, Ulf Bömer, Krzysztof Brzezinka, Niels Lindner, Philip Lienau, Stefan Gradl, Hartmut Beck, Peter J. Brown, Vijayaratnam Santhakumar, Masoud Vedadi, Dalia Baršytė-Lovejoy, C.H. Arrowsmith, Norbert Schmees, Kirstin Petersen
Abstract
USP21 belongs to the ubiquitin-specific protease (USP) subfamily of deubiquitinating enzymes (DUBs). Due to its relevance in tumor development and growth, USP21 has been reported as a promising novel therapeutic target for cancer treatment. Herein, we present the discovery of the first highly potent and selective USP21 inhibitor. Following high-throughput screening and subsequent structure-based optimization, we identified BAY-805 to be a non-covalent inhibitor with low nanomolar affinity for USP21 and high selectivity over other DUB targets as well as kinases, proteases, and other common off-targets. Furthermore, surface plasmon resonance (SPR) and cellular thermal shift assays (CETSA) demonstrated high-affinity target engagement of BAY-805, resulting in strong NF-κB activation in a cell-based reporter assay. To the best of our knowledge, BAY-805 is the first potent and selective USP21 inhibitor and represents a valuable high-quality in vitro chemical probe to further explore the complex biology of USP21.