BAY 1816032 is an orally active, ATP-competitive (Ki = 1.2 μM), highly potent and selective BUB1 inhibitor (IC50 = 6.1 nM with 10 μM ATP; affinity Kd = 3.3 nM/BUB1 vs 57 nM/STK10, 850 nM/DMPK2, 2.3 μM/DDR1 and >2.3 μM toward more than 390 other kinases) th at effectively targets BUB1-dependent cellular signaling (H2A-pThr120 IC50 = 29 nM post 1h treatment of nocodazole-arrested HeLa cells) and tumor cell proliferation in vitro (IC50 range from 0.5 to 5.8 μM in 43 human and mouse cancer cultures) and in human triple-negative breast xenograft models in vivo (25-50 mg/kg twice daily p.o.; SUM-149 and MDA-MB-436).
