In vitro kinase inhibition.

Inhibition of CDK7 activity was measured by incubation of increasing amounts of BS-181 HCl 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 lines

MCF-7 cells

Preparation method

The solubility of this compound in DMSO is >10 mM. General tips for obtaining a higher concentration: Please warm the tube at 37 ℃ for 10 minutes and/or shake it in the ultrasonic bath for a while. Stock solution can be stored below -20 ℃ for several months.

Reaction Conditions

50 μM; 24 hrs

Applications

In MCF-7 cells, BS-181 HCl inhibited the phosphorylation of CDK7 substrates, and promoted cell cycle arrest and apoptosis to inhibit the growth of cancer cell lines.

Animal models

Mice bearing MCF-7 xenografts

Dosage form

10 or 20 mg/kg; i.p.; b.i.d., for 2 weeks

Applications

In mice bearing MCF-7 xenografts, BS-181 HCl inhibited tumor growth in a dose-dependent manner, without apparent toxicity.

Other notes

Please test the solubility of all compounds indoor, and the actual solubility may slightly differ with the theoretical value. This is caused by an experimental system error and it is normal.

IC50: 21 nm (CDK7)

Normal progression through the cell cycle requires the sequential action of cyclin-dependent kinases CDK1, CDK2, CDK4, and CDK6. Direct or indirect deregulation of CDK activity is a feature of almost all cancers and has led to the development of CDK inhibitors as anticancer agents.BS-181 is a highly selective CDK7 inhibitor with IC50 of 21 nM. ; >40-fold selective for CDK7 than CDK1, 2, 4, 5, 6, or 9.

In vitro: BS-181, inhibited CAK activity with an IC50 of 21 nmol/L. Testing of other CDKs as well as another 69 kinases showed that BS-181 only inhibited CDK2 at concentrations lower than 1 μmol/L, with CDK2 being inhibited 35-fold less potently (IC50 880 nmol/L) than CDK7. In MCF-7 cells, BS-181 inhibited the phosphorylation of CDK7 substrates, promoted cell cycle arrest and apoptosis to inhibit the growth of cancer cell lines [1].

In vivo: BS-181 was stable in vivo with a plasma elimination half-life in mice of 405 minutes after i.p. administration of 10 mg/kg. The same dose of drug inhibited the growth of MCF-7 human xenografts in nude mice. BS-181 therefore provides the first example of a potent and selective CDK7 inhibitor with potential as an anticancer agent [1].

Clinical trial: BS-181 is currently in the preclinical development and non clinical trial is ongoing.

Reference:
[1] Ali S, Heathcote DA, Kroll SH, Jogalekar AS, Scheiper B, Patel H, Brackow J, Siwicka A, Fuchter MJ, Periyasamy M, Tolhurst RS, Kanneganti SK, Snyder JP, Liotta DC, Aboagye EO, Barrett AG, Coombes RC.  The development of a selective cyclin-dependent kinase inhibitor that shows antitumor activity. Cancer Res. 2009;69(15):6208-15.