Figure 5.

Compound 16 is selective for EZH2 over other protein methyltransferases. (A) Effects of EPZ-6438, 16, and 17 on inhibiting the EZH2 catalytic activity in an EZH2 methyltransferase assay (³H-labeled S-adenosyl methionine [SAM] was used as the methyl donor). IC₅₀ results shown are the mean values ± SD from duplicate experiments. (B) Effect of 16 on inhibiting the EZH1 catalytic activity in an EZH1 methyltransferase assay (³H-labeled SAM was used as the methyl donor). IC₅₀ results shown are the mean values ± SD from duplicate experiments. (C) Effect of 16 on reducing the EZH1 protein level in MDA-MB-453 cells. MDA-MB-453 cells were treated with DMSO or 16 at the indicated concentration for 48 h. The cell lysates were analyzed by Western blotting to examine the EZH1 protein level. β-Actin and H3 were used as the loading controls. Results shown are representative of at least two independent experiments. (D) Selectivity of compound 16 (at 10 μM) against a panel of 20 protein methyltransferases in radioactive methyltransferase assays. Error bars represent ± SD in duplicate experiments.