Structural optimization and biological evaluation of ML364 based derivatives as USP2a inhibitors.

Ubiquitination is a representative post-translational modification that tags target proteins with ubiquitin to induce protein degradation or modify their functions. Deubiquitinating enzymes (DUBs) play a crucial role in reversing this process by removing ubiquitin from target proteins. Among them, USP2a has emerged as a promising target for cancer therapy due to its oncogenic properties in various cancer types, but its inhibitors have been limited. In this study, our aim was to optimize the structure of ML364, a USP2a inhibitor, and synthesize a series of its derivatives to develop potent USP2a inhibitors. Compound 8v emerged as a potential USP2a inhibitor with lower cytotoxicity compared to ML364. Cellular assays demonstrated that compound 8v effectively reduced the levels of USP2a substrates and attenuated cancer cell growth. We confirmed its direct interaction with the catalytic domain of USP2a and its selective inhibitory activity against USP2a over other USP subfamily proteins (USP7, 8, or 15). In conclusion, compound 8v has been identified as a potent USP2a inhibitor with substantial potential for cancer therapy.

Discovery of dioxo-benzo[b]thiophene derivatives as potent YAP-TEAD interaction inhibitors for treating breast cancer.

Disruption of protein-protein interaction between transcriptional enhancer factor (TEA)-domain (TEAD; a transcription factor) and its co-activator Yes-associated protein (YAP)/ transcriptional co-activator with PDZ-binding motif (TAZ) is a potential therapeutic strategy against various types of solid tumors. Based on hit compound 8 and 9a, hydrazone derivatives with dioxo-benzo[d]isothiazole (9b-n) and oxime ester (10a-s) or amide derivatives (11a-r) with dioxo-benzo[b]thiophene were designed and synthesized as novel TEAD-YAP interaction inhibitors. Amide derivative 11q exhibited a higher potency in inhibiting TEAD-YAP reporter expression activity (IC50 = 12.7 µM), endogenous target gene (e.g., CTGF and CYR61) expression, breast cancer cell growth (GI50 = 3.2 µM), and anchorage-independent growth in soft agar. Molecular docking analysis suggested that the newly synthesized compounds bound to interface 2 of TEAD had lower docking scores compared to the compounds that bind to interface 3; moreover, they were predicted to overlap with YAP. Therefore, we identified 11q as an attractive therapeutic agent for treating solid tumors overexpressing YAP/TAZ.