GSK126 (GSK-2816126; GSK-2816126A) is a selective and SAM (S-adenosyl-methionine)-competitive inhibitor of EZH2 (Enhancer of zeste homolog 2) methyltransferase with anticancer activity. It inhibits EZH2 with an IC50 of 9.9 nM, and shows >1000-fold selective for EZH2 over other human methyltransferases. It exhibits high antiproliferative activity and in vivo antitumor efficacy.

Physicochemical Properties

Molecular Formula	C31H38N6O2
Molecular Weight	526.67
Exact Mass	526.305
CAS #	1346574-57-9
Related CAS #	1346574-57-9
PubChem CID	68210102
Appearance	White to yellow solid powder
Density	1.3±0.1 g/cm3
Boiling Point	823.4±65.0 °C at 760 mmHg
Flash Point	451.8±34.3 °C
Vapour Pressure	0.0±3.0 mmHg at 25°C
Index of Refraction	1.654
LogP	3.14
Hydrogen Bond Donor Count	3
Hydrogen Bond Acceptor Count	5
Rotatable Bond Count	7
Heavy Atom Count	39
Complexity	972
Defined Atom Stereocenter Count	1
SMILES	CC[C@H](C)N1C=C(C2=C(C=C(C=C21)C3=CN=C(C=C3)N4CCNCC4)C(=O)NCC5=C(C=C(NC5=O)C)C)C
InChi Key	FKSFKBQGSFSOSM-QFIPXVFZSA-N
InChi Code	InChI=1S/C31H38N6O2/c1-6-22(5)37-18-20(3)29-25(30(38)34-17-26-19(2)13-21(4)35-31(26)39)14-24(15-27(29)37)23-7-8-28(33-16-23)36-11-9-32-10-12-36/h7-8,13-16,18,22,32H,6,9-12,17H2,1-5H3,(H,34,38)(H,35,39)/t22-/m0/s1
Chemical Name	(S)-1-(sec-butyl)-N-((4,6-dimethyl-2-oxo-1,2-dihydropyridin-3-yl)methyl)-3-methyl-6-(6-(piperazin-1-yl)pyridin-3-yl)-1H-indole-4-carboxamide
Synonyms	GSK-2816126; GSK 2816126; GSK2816126; GSK126; GSK-126; GSK 126
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	Regardless of the substrate employed, GSK126 selectively inhibits the activity of both wild-type and mutant EZH2 methyltransferase with a similar degree of efficacy (Ki=0.5-3 nM). It is competitive with S-adenosylmethionine (SAM) but not with peptide substrates. GSK126 has remarkable selectivity towards many other protein classes and other methyltransferases (EZH1, IC50=680 nM) [1]. Three SCLC cell lines were treated with GSK126 to cause growth inhibition. Lu130, H209, and DMS53 SCLC cell lines were treated with 0.5, 2, and 8 μM GSK126, and the WST-8 test was used to examine the growth curves. GSK126 treatment at 8 μM decreased cell proliferation in all three cell lines, but Lu130 and H209 were more susceptible to GSK126, even at lower dosages [2].
ln Vivo	In female beige SCID mice, GSK126 is given intraperitoneally at a dosage amount of 0.2 mL per 20 g body weight. GSK126 significantly and efficiently suppresses the growth of EZH2 mutant DLBCL xenografts in mice as well as the proliferation of EZH2 mutant DLBCL cell lines[1].
Animal Protocol	Dissolved in 20% captisol; 150 mg/kg; i.p. Female beige SCID mice bearing Pfeiffer or KARPAS-422 tumors
References	[1]. EZH2 inhibition as a therapeutic strategy for lymphoma with EZH2-activating mutations. Nature. 2012 Dec 6;492(7427):108-12. [2]. PRC2 overexpression and PRC2-target gene repression relating to poorer prognosis in small cell lung cancer. Sci Rep. 2013 May 29;3:1911.
Additional Infomation	GSK126 is a member of the class of methylindoles that is 1H-indole substituted by (2S)-butan-2-yl, methyl, N-[(4,6-dimethyl-2-oxo-1,2-dihydropyridin-3-yl)methyl]acetamide, and 6-(piperazin-1-yl)pyridin-3-yl groups at positions 1, 3, 4, and 6, respectively. It is a potent and highly selective inhibitor of EZH2 methyltransferase (IC50 = 9.9 nM). It has a role as a neuroprotective agent, an antiatherosclerotic agent, an antineoplastic agent, an anti-obesity agent, an angiogenesis inhibitor and an EC 2.1.1.43 (enhancer of zeste homolog 2) inhibitor. It is a member of pyridines, a secondary carboxamide, a pyridone, a N-arylpiperazine and a methylindole. EZH2 Inhibitor is any agent that inhibits the histone lysine methyltransferase EZH2.

Solubility Data

Solubility (In Vitro)

DMSO: 3 mg/mL (5.7 mM) Water:<1 mg/mL Ethanol:<1 mg/mL

Solubility (In Vivo)

Solubility in Formulation 1: ≥ 1.25 mg/mL (2.37 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 12.5 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: 1.25 mg/mL (2.37 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), suspension solution; with ultrasonication. For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 12.5 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: ≥ 1.25 mg/mL (2.37 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 12.5 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly. Solubility in Formulation 4: ≥ 0.82 mg/mL (1.56 mM) (saturation unknown) in 5% DMSO + 40% PEG300 + 5% Tween80 + 50% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution. Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution. Solubility in Formulation 5: ≥ 0.82 mg/mL (1.56 mM) (saturation unknown) in 5% DMSO + 95% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), clear solution. 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 6: 4% DMSO+corn oil:0.5mg/mL Solubility in Formulation 7: 10 mg/mL (18.99 mM) in 50% PEG300 50% Saline (add these co-solvents sequentially from left to right, and one by one), suspension solution; with ultrasonication. Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution. Solubility in Formulation 8: 20 mg/mL (37.97 mM) in 20% SBE-β-CD adjusted to pH 4-4.5 with 1 N acetic (add these co-solvents sequentially from left to right, and one by one), clear solution; with heating and sonication.  (Please use freshly prepared in vivo formulations for optimal results.)

Preparing Stock Solutions		1 mg	5 mg	10 mg
	1 mM	1.8987 mL	9.4936 mL	18.9872 mL
	5 mM	0.3797 mL	1.8987 mL	3.7974 mL
	10 mM	0.1899 mL	0.9494 mL	1.8987 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.