Verticillin A is found to be a potent inhibitor of histone methyltransferases, selective for G9a, GLP, SUV39H1, SUV39H2, MLL1, and NSD2. Methods of using Verticillin A are provided. The Verticillin A can be synthetically produced or it can be isolated from natural sources. Methods if inhibiting one or more histone methyltransferases are provided. In addition, methods are provided for treating diseases or disorders related to overexpression of one or more histone methyltransferases. Exemplary diseases and disorders to be treated include cancer, asthma, HIV, and progeria.
