MS1943 is a first-in-class, orally bioavailable EZH2 selective degrader, with an IC50 of 120 nM. MS1943 significantly reduces EZH2 protein levels in numerous triple-negative breast cancer (TNBC) and other cancer and noncancerous cell lines. MS1943 effectively blocks proliferation of multiple TNBC and other cancer cell lines.In Vitro:MS1943 (0.625-5 μM; 3 days) inhibits cell growth with an GI50 of 2.2 μM.
MS1943 (0.625-5 μM; 4 days) induces cell death in MDA-MB-468 cells. MS1943 effectively reduces EZH2 levels in BT549, HCC70 and MDA-MB-231 TNBC cells, as well as KARPAS-422 and SUDHL8 lymphoma cells and PNT2 non-cancerous prostate cells.
MS1943 (1.25-5.0 μM; 2 days) inhibits EZH2 and SUZ12 protein levels in a concentration- and timedependent manner, without affecting EED protein levels, whereas the H3K27me3 mark was also suppressed.In Vivo:MS1943 (150 mg/kg body weight; i.p.; once daily for 36 days) suppresses tumor growth.
MS1943 induces apoptosis in the MDA-MB-468 xenograft model.
A single i.p. injection of MS1943 at 50 mg/kg body weight achieved a peak plasma concentration (Cmax) of 2.9 μM and resulted in plasma concentrations above its cellular IC50 value for ~2h. A single 150 mg/kg body weight p.o. dose achieved Cmax of 1.1 μM, but plasma concentrations were below the cellular IC50 value.