A-395 is an antagonist of polycomb repressive complex 2 (PRC2) protein-protein interactions that potently inhibits the trimeric PRC2 complex (EZH2-EED-SUZ12, IC50: 18 nM).

PRC2:18 nM

The embryonic ectoderm development (EED) protein is an essential subunit of PRC2. A-395 antagonizes the H3K27me3 binding functions of EED by binding to the H3K27me3-binding pocket, thereby preventing the allosteric activation of PRC2's catalytic activity. A-395 competes for H3K27me3 peptide binding to EED (IC50: 7 nM) and selectively modulates PRC2 activity in cells, markedly reducing the H3K27 methyl mark. A-395 inhibits H3K27me2 and H3K27me3 (IC50s: 390 nM and 90 nM, respectively) and induces growth inhibition in human tumor cell lines sensitive to SAM-competitive EZH2 inhibitors, unlike its close chemical analog A-395N.

1,000 multiple myeloma cells are seeded in each well of 96-well cell culture plates and treated with A-395 (0.001-100 μM) or DMSO control for 10 d before the cell proliferation assay. Cell proliferation assays are conducted with the CellTiter-Glo Luminescent Cell Viability Assay.