Inhibitory activities

Biochemical assays used the five-member PRC2 complex (human Flag-EZH2, EED, SUZ12, AEBP2, RbAp48) containing either wild-type or mutant EZH2, [3H]-SAM and histone H3 peptides (21-44) with K27me0, K27me1 or K27me2 were used as substrates, reactions were incubated for 30 min. Global histone modification levels were determined by enzyme-linked immunosorbent assay (ELISA) or western blot methods using antibodies specific for total histoneH3, H3K27me1, H3K27me2 orH3K27me3.

Cell lines

Lu130, H209, and DMS53 small cell lung cancer (SCLC) cell lines.

Preparation method

Dissolved in DMSO. General tips for obtaining a higher concentration: Please warm the tube at 37℃ for 10 minutes and/or shake it in the ultrasonic bath for a while. Stock solution can be stored below -20℃ for several months.

Reaction Conditions

0.5, 2, and 8 μM; 72, 144, 192 h.

Applications

GSK126 inhibited cell growth in all the three cell lines at 8 μM.

Animal models

Mice using subcutaneous xenografts of KARPAS-422 and Pfeiffer cells.

Dosage form

15, 50, 150 mg/kg, 10 days of once daily; 300 mg/kg twice per week; administered intraperitoneally.

Applications

GSK126 decreases H3K27me3 and increases gene expression in a dose-dependent way. GSK126 completely inhibited tumour growth at 50 mg/kg and increases survival of mice bearing the more aggressive KARPAS-422 tumours. GSK126 was well tolerated at the doses and schedules examined as measured by little to no decrease in body weight.

Other notes

Please test the solubility of all compounds indoor, and the actual solubility may slightly differ with the theoretical value. This is caused by an experimental system error and it is normal.

GSK126 is an inhibitor of EZH2 with Ki Value of 93 pM [1].

Over-expression of EZH2 has been reported to be correlated with cancer progression and poor prognosis, high grade and high stage in several tumor types. GSK126 is a potent inhibitor of EZH2 and its functional residence time on activated form of EZH2/PRC2 is mush longer than unactivated forms [1]. When tested with lymphoma cell lines, results showed that harboring EZH2 mutations such as Y641N, Y641F or A677G were more sensitivity [2]. In DMS53, Lu30, H209 SCLC cells, cellular growth was inhibited with 0.5, 2, and 8μM GSK126 treatment [3]. And GSK126 could also significantly restore ARNTL expression in ovarian cancer cells thus inhibit cell growth and enhance chemosensitivity of cisplatin [4].

Intermittent dosing of GSK126 treated subcutaneous KARPAS-422 xenografts model could effectively inhibit its growth with or without a 1 week drug holiday. In mouse model with EZH2 mutant DLBCL xenografts, treatment with GSK126 could markedly inhibit its growth [2].

References:
1. Sato, T., et al., PRC2 overexpression and PRC2-target gene repression relating to poorer prognosis in small cell lung cancer. Sci Rep, 2013. 3(1911).
2. McCabe, M.T., et al., EZH2 inhibition as a therapeutic strategy for lymphoma with EZH2-activating mutations. Nature, 2012. 492(7427): p. 108-12.
3. Van Aller, G.S., et al., Long residence time inhibition of EZH2 in activated polycomb repressive complex 2. ACS Chem Biol, 2014. 9(3): p. 622-9.
4. Yeh, C.M., et al., Epigenetic silencing of ARNTL, a circadian gene and potential tumor suppressor in ovarian cancer. Int J Oncol, 2014. 45(5): p. 2101-7.