MS023 is an inhibitor of type I protein arginine methyltransferases (PRMTs; IC50s = 30, 119, 83, 4, and 5 nM for PRMT1, -3, -4, -6, and -8, respectively). It is selective for these type I PRMTs over PRMT5, -7, and -9, as well as a panel of 25 protein lysine methyltransferases (PKMTs) and DNA methyltransferases (DNMTs) when used at a concentration of 10 μM. It inhibits the methylation of histone 4 at arginine 3 (H4R3) in MCF-7 breast cancer cells (IC50 = 9 nM) and H3R2 in HEK293 cells (IC50 = 56 nM). MS023 (20 μM) also inhibits the methylation of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) nucleocapsid protein and the replication of SARS-CoV-2 in Vero E6 cells. It reduces tumor growth in a Huh7 mouse xenograft model when administered at a dose of 160 mg/kg.
