Discovery of Highly Potent and Selective EZH2 Covalent Inhibitors via Incorporating Basic Amines

Targeted covalent inhibition is a promising strategy to address the high dose and acquired drug resistance issues of the first-generation EZH2 noncovalent inhibitors. Recently we have reported a new generation of highly potent EZH2 covalent inhibitors, but further optimization to enhance aqueous solubility is required. Here, we described the systematic optimization of EPZ-6438 by preserving the aqueous groups, resulting in the identification of a highly potent and selective EZH2 covalent inhibitor 13, which displayed nanomolar potency in biochemical and cellular assays. Moreover, SAM competition experiments preliminarily confirmed that 13 was noncompetitive with SAM, leading to the remarkable reduction of the H3K27Me3 marker. In addition, 13 exhibited superior cell growth inhibition in the EZH2 mutant cancer cell lines. The discovery of 13 holds promise for the development of highly potent EZH2 covalent inhibitors.