BS-181 HCl

Catalog No.S1572

For research use only.

BS-181 HCl is a highly selective CDK7 inhibitor with IC50 of 21 nM. It is more than 40-fold selective for CDK7 than CDK1, 2, 4, 5, 6, or 9.

BS-181 HCl Chemical Structure

CAS No. 1397219-81-6 

Selleck's BS-181 HCl has been cited by 14 publications

Purity & Quality Control

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Biological Activity

Description BS-181 HCl is a highly selective CDK7 inhibitor with IC50 of 21 nM. It is more than 40-fold selective for CDK7 than CDK1, 2, 4, 5, 6, or 9.
Features Demonstrates higher inhibitory selectivity for CDK7 vs. other CDKs and kinases from other classes.
CDK7 [1]
(Cell-free assay)
21 nM
In vitro

BS-181 is a small molecule inhibitor of CDK7 in a cell-free environment, which displays more potential activity than roscovitine with IC 50 of 510 nM. Among the CDKs and other 69 kinases from many different classes, BS-181 shows high inhibitory selectivity for CDK7, inhibits CDK2 at concentrations lower than 1 μM which being inhibited 35-fold less potently (IC50 with 880 nM) than CDK7, shows slight inhibition for CDK1, CDK4, CDK5, CDK6 and CDK9 with IC50 values higher than 3.0 μM, and only shows inhibition for several kinases from other classes at high concentrations (>10 μM). BS-181 promotes cell cycle arrest and inhibits the cancer cell growth of a range of tumor types, including breast, lung, prostate and colorectal cancer with IC50 in the range of 11.5-37 μM. In MCF-7 cells, BS-181 inhibits the phosphorylation of the CDK7 substrate RNA polymerase II COOH-terminal domain (CTD), and promotes cell cycle arrest and apoptosis to inhibit the growth of cancer cell lines. [1]

In vivo BS-181 is stable in vivo with a plasma elimination half-life in mice of 405 minutes after i.p. administration of 10 mg/kg. BS-181 inhibits the growth of MCF-7 xenografts in the nude mice model in a dose-dependent manner, with 25% and 50% reduction in tumor growth after 2 weeks of treatment at 10 mg/kg/day and 20 mg/kg/day, respectively without apparent toxicity. [1]

Protocol (from reference)

Kinase Assay:[1]
  • 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 Research:[1]
  • Cell lines: MCF-7 cells
  • Concentrations: Dissolved in DMSO, final concentration ~50 μM
  • Incubation Time: 24 hours
  • Method: MCF-7 cells are exposed to BS-181 for 24 hours. For the determination of cell cycle and apoptosis, cells are stained with propidium iodide or labeled with Annexin V-FITC, then labeled cells are acquired within 1 hour, by using the RXP cytomics software on a Beckman Coulter Elite ESP, and the data are analyzed using Flow Jo v7.2.5. For the assessment of CDKs, cells are lysed and analyzed by western blotting.
  • (Only for Reference)
Animal Research:[1]
  • Animal Models: MCF-7 cells are established in female nu/nu-BALB/c athymic nude mice
  • Dosages: 10 or 20 mg/kg
  • Administration: Twice daily by i.p. injection
  • (Only for Reference)

Solubility (25°C)

In vitro

DMSO 83 mg/mL
(199.04 mM)
Ethanol 22 mg/mL warmed
(52.75 mM)
Water 3 mg/mL
(7.19 mM)

In vivo

Add solvents to the product individually and in order
(Data is from Selleck tests instead of citations):
1% DMSO+30% polyethylene glycol+1% Tween 80
For best results, use promptly after mixing.

30 mg/mL

* Please note that Selleck tests the solubility of all compounds in-house, and the actual solubility may differ slightly from published values. This is normal and is due to slight batch-to-batch variations.

Chemical Information

Molecular Weight 416.99


CAS No. 1397219-81-6 
Storage 3 years -20°C powder
2 years -80°C in solvent

In vivo Formulation Calculator (Clear solution)

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Method for preparing DMSO master liquid: mg drug pre-dissolved in μL DMSO ( Master liquid concentration mg/mL, Please contact us first if the concentration exceeds the DMSO solubility of the batch of drug. )

Method for preparing in vivo formulation: Take μL DMSO master liquid, next addμL PEG300, mix and clarify, next addμL Tween 80, mix and clarify, next add μL ddH2O, mix and clarify.

Method for preparing in vivo formulation: Take μL DMSO master liquid, next add μL Corn oil, mix and clarify.

Note: 1. Please make sure the liquid is clear before adding the next solvent.
2. Be sure to add the solvent(s) in order. You must ensure that the solution obtained, in the previous addition, is a clear solution before proceeding to add the next solvent. Physical methods such
as vortex, ultrasound or hot water bath can be used to aid dissolving.

Molarity Calculator

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Tech Support

Answers to questions you may have can be found in the inhibitor handling instructions. Topics include how to prepare stock solutions, how to store inhibitors, and issues that need special attention for cell-based assays and animal experiments.

Handling Instructions

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