A-366

A-366 is a potent, highly selective, peptide-competitive histone methyltransferase G9a inhibitor with IC₅₀s of 3.3 and 38 nM for G9a and GLP (EHMT1), respectively. A-366 shows >1000-fold selectivity over 21 other methyltransferases. A-366 is also a potent, nanomolar inhibitor of the Spindlin1-H3K4me3-interaction (IC₅₀=182.6 nM). A-366 displays high affinity at human histamine H3 receptor (K_i=17 nM) and shows subtype selectivity among subsets of the histaminergic and dopaminergic receptor families^[1][2][3][4]. In Vitro:A-366 (0.01-10 μM; 14 days) induces differentiation and affects viability in MV4;11 cells^[4].
A-366 (0.3-3 μM; 72 hours) reduces the total levels of H3K9me2 in a time and concentration dependent manner with a cellular EC50 of ~300 nM in PC-3 prostate adenocarcinoma cells. A-366 (0.01-10 μM; 4 days; HL-60 cells) results in a dose-dependent differentiation and a corresponding decrease in proliferation. DNA content analysis of A-366-treated HL-60 cells showed an accumulation of cells in G1 consistent with cytostasis^[4]. In Vivo:A-366 (30 mg/kg; osmotic mini-pump; daily for 14 days) treatment of MV4;11 xenografts elicits growth inhibition^[4].