GSK503

GSK503 is a potent and specific inhibitor of EZH2 methyltransferase with Kiapp values of 3 to 27 nM.

Signaling Pathways >> Epigenetics >> Epigenetic Reader Domain

Signaling Pathways >> Epigenetics >> Histone Methyltransferase

Research Areas >> Cancer

Ki: 3 to 27 nM (EZH2)[1]

GSK503 inhibits the methyltransferase activity of wild type and mutant EZH2 with similar potency (Kiapp=3-27 nM) and is structurally related to GSK126 and GSK343. GSK503 is >200 fold selective over EZH1 (Kiapp=636 nM) and >4000 fold selective over other histone methyltransferases[1].

In a melanoma mouse model, conditional EZH2 ablation as much as treatment with the GSK503 stabilizes the disease through inhibition of growth and virtually abolishes metastases formation without affecting normal melanocyte biology[2]. GSK503 displays favorable pharmacokinetics in mice. GSK503, but not vehicle, prevents the formation of germinal center after SRBC or NP-KLH immunization, phenocopying the Ezh2 null phenotype. GSK503 treatment leads to reduced numbers of GC B-cells by flow cytometry, reduces number and volume of GCs by immunohistochemistry, and impairs formation high affinity antibodies[1].

Mice: To pharmacologically inhibit Ezh2 activity, Tyr::N-RasQ61K Ink4a-/- and C57Bl/6 mice are subjected to treatment with GSK503, which is diluted (15 mg/mL) in 20% Captisol solution. Efficient Ezh2 inhibition is achieved by daily intraperitoneal injections of 150 mg/kg GSK503 over 35 consecutive days. Mice are monitored during and after treatment to measure GSK503-induced reversible weight loss. C57Bl/6 and Foxn1nu/nu mice engrafted with melanoma cells are subjected to TM and GSK503 treatment as described above[2].

[1]. Béguelin W, et al. EZH2 is required for germinal center formation and somatic EZH2 mutations promote lymphoid transformation. Cancer Cell. 2013 May 13;23(5):677-92.

[2]. Zingg D, et al. The epigenetic modifier EZH2 controls melanoma growth and metastasis through silencing of distinct tumour suppressors. Nat Commun. 2015 Jan 22;6:6051.

(+)-JQ1 | GSK126 | Tazemetostat (EPZ-6438) | Birabresib (OTX015) | A 485 | Curcumin | ARV-771 | ARV-825 | I-BET762 | BI 2536 | UNC 0642 | GSK343 | C646 | Pinometostat (EPZ5676) | 3-Deazaneplanocin A (hydrochloride)