CCT251921 is a novel, potent, selective, and orally bioavailable small-molecule inhibitor of CDK8 and CDK19 (IC50 =2.3 nM; CDK19 = 2.6 nM). CCT251921 showed the optimal compromise of in vitro bioactive compound, pharmacokinetic, and physicochemical properties and is suitable for progression to animal models of cancer. The Mediator complex-associated cyclin-dependent kinase CDK8 has been implicated in human disease, particularly in colorectal cancer where it has been reported as a putative oncogene.

Physicochemical Properties

Molecular Formula	C21H23CLN6O
Molecular Weight	410.8999
Exact Mass	410.162
CAS #	1607837-31-9
PubChem CID	74222277
Appearance	White to off-white solid powder
Density	1.5±0.1 g/cm3
Boiling Point	696.4±55.0 °C at 760 mmHg
Flash Point	375.0±31.5 °C
Vapour Pressure	0.0±2.2 mmHg at 25°C
Index of Refraction	1.757
LogP	2.78
Hydrogen Bond Donor Count	2
Hydrogen Bond Acceptor Count	5
Rotatable Bond Count	2
Heavy Atom Count	29
Complexity	626
Defined Atom Stereocenter Count	0
InChi Key	VPJXPDLMACOGIZ-UHFFFAOYSA-N
InChi Code	InChI=1S/C21H23ClN6O/c1-27-16-3-2-13(10-14(16)11-26-27)15-12-25-19(23)17(22)18(15)28-8-5-21(6-9-28)4-7-24-20(21)29/h2-3,10-12H,4-9H2,1H3,(H2,23,25)(H,24,29)
Chemical Name	8-(2-amino-3-chloro-5-(1-methyl-1H-indazol-5-yl)pyridin-4-yl)-2,8-diazaspiro[4.5]decan-1-one
Synonyms	CCT251921 CCT-251921 CCT 251921
HS Tariff Code	2934.99.9001
Storage	Powder-20°C 3 years 4°C 2 years In solvent -80°C 6 months -20°C 1 month
Shipping Condition	Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

Biological Activity

ln Vitro	Tested on a panel of 279 kinases, 55 receptors, ion channels, and enzymes at 1 μM, CCT-251921 has an acceptable water solubility and minimal activity; weak inhibition of CYP was seen. In human cancer cell lines with constitutively activated WNT pathway signaling, such as LS174T (β-catenin mutant), SW480, Colo205 (APC mutant), or PA-1 human teratocarcinoma WNT ligand-dependent cells, CCT-251921 exhibits potent inhibition of reporter gene-based readouts measuring basal WNT pathway activity [1].
ln Vivo	For the purpose of advancing preclinical efficacy and safety investigations as well as facilitating additional assessment of CDK8/19 pharmacology, CCT-251921 shows enhanced oral pharmacokinetics and pharmacological characteristics. CCT-251921 therapy decreased mouse tumor weight (54.2%) at day 15 in an APC mutant SW620 human colorectal cancer xenograft model. After the last dosage, STAT1SER727 phosphorylation inhibition lasts for longer than six hours [1].
References	[1]. Discovery of Potent, Selective, and Orally Bioavailable Small-Molecule Modulators of the Mediator Complex-Associated Kinases CDK8 and CDK19. J Med Chem. 2016 Feb 11;59(3):1078-101.

Solubility Data

Solubility (In Vitro)

DMSO : ~25 mg/mL (~60.84 mM)

Solubility (In Vivo)

Solubility in Formulation 1: ≥ 2.5 mg/mL (6.08 mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution. For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL. Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution. Solubility in Formulation 2: ≥ 2.5 mg/mL (6.08 mM) (saturation unknown) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), clear solution. For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly. Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution. Solubility in Formulation 3: ≥ 2.5 mg/mL (6.08 mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution. For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.  (Please use freshly prepared in vivo formulations for optimal results.)

Preparing Stock Solutions		1 mg	5 mg	10 mg
	1 mM	2.4337 mL	12.1684 mL	24.3368 mL
	5 mM	0.4867 mL	2.4337 mL	4.8674 mL
	10 mM	0.2434 mL	1.2168 mL	2.4337 mL

*Note: Please select an appropriate solvent for the preparation of stock solution based on your experiment needs. For most products, DMSO can be used for preparing stock solutions (e.g. 5 mM, 10 mM, or 20 mM concentration); some products with high aqueous solubility may be dissolved in water directly. Solubility information is available at the above Solubility Data section. Once the stock solution is prepared, aliquot it to routine usage volumes and store at -20°C or -80°C. Avoid repeated freeze and thaw cycles.