AtomNet-Aided OTUD7B Inhibitor Discovery and Validation

SIMPLE SUMMARY: Protein deubiquitinases are an important family of enzymes commonly deregulated in cancer. However, few deubiquitinase inhibitors have been identified and used in cancer treatment. Here, using an artificial intelligence (AI) AtomNet guided screening pipeline, we searched 4 million compounds for potential OTUD7B inhibitors and validated one compound with a series of in vivo and in vitro assays. This compound, 7Bi, efficiently inhibited OTUD7B activity both in cells and in vitro, leading to reduced cancer cell proliferation. These data show a promise to use 7Bi in treating cancers with increased OTUD7B expression including both breast and lung cancer. ABSTRACT: Protein deubiquitinases play critical pathophysiological roles in cancer. Among all deubiquitinases, an oncogenic function for OTUD7B has been established in genetic NSCLC murine models. However, few deubiquitinase inhibitors have been developed due to technical challenges. Here, we report a putative small molecule OTUD7B inhibitor obtained from an AI-aided screen of a 4 million compound library. We validated the effects of the OTUD7B inhibitor (7Bi) in reducing Akt-pS473 signals in multiple NSCLC and HEK293 cells by blocking OTUD7B-governed GβL deubiquitination in cells, as well as inhibiting OTUD7B-mediated cleavage of K11-linked di-ub in an in vitro enzyme assay. Furthermore, we report in leukemia cells, either genetic depletion or 7Bi-mediated pharmacological inhibition of OTUD7B reduces Akt-pS473 via inhibiting the OTUD7B/GβL signaling axis. Together, our study identifies the first putative OTUD7B inhibitor showing activities both in cells and in vitro, with promising applications as a therapeutic agent in treating cancer with OTUD7B overexpression.