CK-636 (also called CK636; CK-0944636; CK0944636) is a potent inhibitor of the actin-related protein (Arp2/3) complex with IC50 values of 4 μM, 24 μM and 32 μM for inhibition of actin polymerization induced by human, fission yeast and bovine Arp2/3 complex, respectively. CK-636 binds between Arp2 and Arp3 where it appears to block movement of Arp2 and Arp3 into their active conformation and inhibits Arp2/3 complex’s ability to nucleate actin filaments. In a concentration dependence way, CK-636 reduced the formation of actin filament comet tails by Listeria with IC50 value of 22 μM in infected SKOV3 cells.

Physicochemical Properties

Molecular Formula	C16H16N2OS
Molecular Weight	284.38
Exact Mass	284.098
CAS #	442632-72-6
Related CAS #	442632-72-6
PubChem CID	588963
Appearance	Light yellow to yellow solid powder
Density	1.3±0.1 g/cm3
Boiling Point	576.8±45.0 °C at 760 mmHg
Flash Point	302.6±28.7 °C
Vapour Pressure	0.0±1.6 mmHg at 25°C
Index of Refraction	1.674
LogP	3.1
Hydrogen Bond Donor Count	2
Hydrogen Bond Acceptor Count	2
Rotatable Bond Count	4
Heavy Atom Count	20
Complexity	349
Defined Atom Stereocenter Count	0
InChi Key	ACAKNPKRLPMONU-UHFFFAOYSA-N
InChi Code	InChI=1S/C16H16N2OS/c1-11-12(13-5-2-3-6-14(13)18-11)8-9-17-16(19)15-7-4-10-20-15/h2-7,10,18H,8-9H2,1H3,(H,17,19)
Chemical Name	N-[2-(2-Methyl-1H-indol-3-yl)ethyl]-2-thiophenecarboxamide
Synonyms	CK0944636; CK636; CK-0944636; CK 636;CK 0944636; CK-636
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	Arp2 and Arp3 appear to be prevented from adopting their active conformations by CK-636, which binds between them. CK-636 modifies the conformation of Arp3 by inserting into its hydrophobic core. Infected SKOV3 cells (IC50=22 μM), CK-636 inhibits actin polymerization and Listeria monocytogenes' production of actin filament comet tails [1]. T cells treated with CK-636 also exhibited an elongated morphology with sharp pseudopodia at the leading edge, and their width was roughly 30% less than that of T cells treated with DMSO [2].
ln Vivo
Animal Protocol
References	[1]. Characterization of two classes of small molecule inhibitors of Arp2/3 complex. Nature. 2009 Aug 20;460(7258):1031-4. [2]. Migration of T cells on surfaces containing complex nanotopography. PLoS One. 2013 Sep 12;8(9):e73960. [3]. Discovery of the migrasome, an organelle mediating release of cytoplasmic contents during cell migration. Cell Res. 2015 Jan;25(1):24-38.

Solubility Data

Solubility (In Vitro)

DMSO:57 mg/mL (200.4 mM) Water:<1 mg/mL Ethanol:50 mg/mL (175.8 mM)

Solubility (In Vivo)

Solubility in Formulation 1: ≥ 2.5 mg/mL (8.79 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 (8.79 mM) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), suspension solution; with ultrasonication. 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 (8.79 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	3.5164 mL	17.5821 mL	35.1642 mL
	5 mM	0.7033 mL	3.5164 mL	7.0328 mL
	10 mM	0.3516 mL	1.7582 mL	3.5164 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.