BS-181 is a highly selective CDK7 inhibitor (IC50: 21 nM); >40-fold selective for CDK7 than CDK1/2/4/5/6/9.

CDK7:21 nM

BS-181促进细胞周期停滞并抑制癌细胞生长，所有测试细胞系的生长均被抑制，IC50值介于11.5至37μM之间。BS-181以约15μM的表观IC50值抑制RB在Ser795和Ser821的磷酸化，与P-Ser2抑制的IC50相似。BS-181处理MCF-7细胞导致G1期停滞及凋亡[1]。BS-181抑制GC细胞和正常胃上皮RGM-1细胞系的生长，其抑制浓度（IC50）分别为17至22μM和6.5μM。BS-181显著以剂量依赖性方式抑制细胞迁移和侵袭能力[2]。

BS-181（5 mg/kg、10 mg/kg，腹腔内）能够抑制裸鼠中MCF-7肿瘤的生长。通过静脉注射（i.v）和腹腔内注射10 mg/kg的BS-181显示出快速清除[1]。BS-181（每天10 mg/kg或20 mg/kg，腹腔内）与对照组相比，显著以剂量依赖的方式抑制肿瘤生长[2]。

In vitro kinase inhibition.: Inhibition of CDK7 activity is measured by incubation of increasing amounts of BS-181 with purified recombinant CDK7/CycH/MAT1 complex, followed by measurement of free ATP remaining in the reaction using a luciferase assay, luciferase activity therefore providing a measure of inhibition of CDK7 activity for the determination of IC50.

Cell viability is detected using Cell Counting Kit (CCK-8 kit) according to supplier's introductions. Briefly, BGC823 cells are seeded at 104?cells per well for 48 hours with or without BS-181. Then, the absorbance is detected at 450 nm (reference at 650 nm) in each well.