Catalog No.S7159 Synonyms: OTS167

For research use only.

OTSSP167 (OTS167) is a highly potent MELK (maternal embryonic leucine zipper kinase) inhibitor with IC50 of 0.41 nM.

OTSSP167 Chemical Structure

CAS No. 1431697-89-0

Selleck's OTSSP167 has been cited by 13 publications

Purity & Quality Control

Choose Selective MELK Inhibitors

Biological Activity

Description OTSSP167 (OTS167) is a highly potent MELK (maternal embryonic leucine zipper kinase) inhibitor with IC50 of 0.41 nM.
Features MELK-selective inhibitor.
MELK [1]
(Cell-free assay)
0.41 nM
In vitro

OTSSP167 inhibits A549, T47D, DU4475, and 22Rv1 cancer cells, in which MELK is highly expressed, with IC50 values of 6.7, 4.3, 2.3, and 6.0 nM, respectively. OTSSP167 inhibited the phosphorylation of PSMA1 (proteasome subunit alpha type 1) and DBNL (drebrin-like), which are novel MELK substrates and are important for stem-cell characteristics and invasiveness. OTSSP167 suppresses mammosphere formation of breast cancer cells through the inhibition of PSMA1 phosphorylation. [1]

In vivo OTSSP167 exhibits significant tumor growth suppression in xenograft studies using breast, lung, prostate, and pancreas cancer cell lines in mice by both intravenous and oral administration. In MDA-MB-231 model, intravenous administration of OTSSP167 at 20 mg/kg once every two days results in TGI of 73% The oral administration at 10 mg/kg once a day reveals TGI of 72%. OTSSP167 for multiple cancer types in dose-dependent and MELK-dependent manners with no or a little body-weight loss. [1]

Protocol (from reference)

Kinase Assay:[1]
  • in vitro kinase assay:

    MELK recombinant protein (0.4 μg) is mixed with 5 μg of each substrate in 20 μL of kinase buffer containing 30 mM Tris-HCl (pH), 10 mM DTT, 40 mM NaF, 10 mM MgCl2, 0.1 mM EGTA with 50 μM cold-ATP and 10 Ci of [γ-32P]ATP for 30 min at 30 °C. The reaction is terminated by addition of SDS sample buffer and boiled for 5 min prior to SDS-PAGE. The gel is dried and autoradiographed with intensifying screens at room temperature. OTSSP167 (final concentration of 10 nM) is dissolved in DMSO and added to kinase buffer before the incubation.

Cell Research:[1]
  • Cell lines: A549, T47D, DU4475, and 22Rv1, HT1197
  • Concentrations: 0.005-0.1 μM
  • Incubation Time: 72 h
  • Method: Cell Counting Kit-8
Animal Research:[1]
  • Animal Models: MDA-MB-231, A549, DU145 xenografts
  • Dosages: 1 mg/kg , 5mg/kg ,10 mg/kg, 20 mg/kg
  • Administration: oral

Solubility (25°C)

In vitro

Chemical Information

Molecular Weight 487.42


CAS No. 1431697-89-0
Storage 3 years -20°C powder
2 years -80°C in solvent
Smiles CC(=O)C1=CN=C2C=CC(=NC2=C1NC3CCC(CC3)CN(C)C)C4=CC(=C(C(=C4)Cl)O)Cl

In vivo Formulation Calculator (Clear solution)

Step 1: Enter information below (Recommended: An additional animal making an allowance for loss during the experiment)

mg/kg g μL

Step 2: Enter the in vivo formulation (This is only the calculator, not formulation. Please contact us first if there is no in vivo formulation at the solubility Section.)

% DMSO % % Tween 80 % ddH2O

Calculation results:

Working concentration: mg/ml;

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

Mass Concentration Volume Molecular Weight

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

Tel: +1-832-582-8158 Ext:3
If you have any other enquiries, please leave a message.

* Indicates a Required Field

Please enter your name.
Please enter your email. Please enter a valid email address.
Please write something to us.
Tags: buy OTSSP167 | OTSSP167 supplier | purchase OTSSP167 | OTSSP167 cost | OTSSP167 manufacturer | order OTSSP167 | OTSSP167 distributor