BS-181

BS-181 is a potent, selective CDK7 inhibitor with IC50 of 21 nM, 40-fold selectivity over CDK2/cycE and no significant activity against CDK1/cycB, CDK4/cycD1, CDK5/p35NCK, CDK6/cycD1, and CDK9/cycT (IC50>1 uM) ; promotes cell cycle arrest and inhibits cancer cell growth in a panel of cell lines representing a range of tumor types (IC50=1.5 to 37 uM), inhibits the phosphorylation of CDK7 substrates, inhibits phosphorylation of the RNA polymerase II COOH-terminal domain (CTD) at P-Ser5 (IC50=9 uM), inhibits RB phosphorylation at Ser795 and Ser821 (IC50=15 uM) ; induces apoptosis in vitro, and shows antitumor effects in vivo.