Background:

EPZ015666 is a potent and selective inhibitor of PRMT5 with IC50 value of 22 nM [1].

Protein arginine methyltransferase-5 (PRMT5) is an enzyme that plays an important role in many cellular processes including tumorigenesis [1].

EPZ015666 is an orally bioavailable PRMT5 inhibitor. In a competitive inhibition model, EPZ015666 inhibited PRMT5 with Ki value of 5 nM and exhibited >20000-fold selectivity over 20 other protein methyltransferases (PMTs). In MCL cell lines Z-138, Mino, Maver-1, Granta-519 and Jeko-1, EPZ015666 decreased the level of SmD3, which was a PRMT5 substrate in a concentration-dependent way. Also, EPZ015666 reduced SmD3me2s in all cell lines. The cellular thermal shift assay (CETSA) in A375 cells showed that EPZ015666 specifically bound to PRMT5. EPZ015666 showed potent antiproliferative effects with IC50 values of 96, 450 and 61-904 nM for Z-138, Maver-1 and additional MCL cell lines respectively in a concentration-dependent way [1].

In SCID mice bearing Z-138 and Maver-1 xenografts, EPZ015666 (25, 50, 100 and 200 mg/kg) showed tumor-growth inhibition (TGI) in a dose-dependent way [1].

Reference:
[1].? Chan-Penebre E, Kuplast KG, Majer CR, et al. A selective inhibitor of PRMT5 with in vivo and in vitro potency in MCL models. Nat Chem Biol, 2015, 11(6): 432-437.