Discovery of potential epigenetic inhibitors against histone methyltransferases through molecular docking and molecular dynamics simulations

Histone methyltransferases (HMTases) catalyze histone methylations that are the important epigenetic marks regulating gene expression, cell fate, and disease progression. In this study, we investigated potential epigenetic inhibitors against HMTases through in silico approaches, including ensembled molecular docking and molecular dynamics simulations (MDS).We identified three candidate compounds, including echinomycin, emetine, and streptonigrin, which showed interactions with HMTases. Echinomycin showed similar binding affinity with H3K4-HMTase NSD3 and H3K9-HMTase SETDB1 but streptonigrin and emetine had preferential binding affinity with NSD3 and SETDB1, respectively. The binding of NSD3 to streptonigrin and echinomycin and binding of SETDB1 to emetine and echinomycin were further confirmed by the results of hydrogen bonding profile and MM/PBSA calculations. Together, our results uncover the binding affinities of echinomycin, emetine, and streptonigrin with histone methyltransferases, and suggest that these compounds are potential epigenetic inhibitors regulating cell activities.