Synthesis and structure-activity relationship studies of LLY-507 analogues as SMYD2 inhibitors

SET and MYND domain-containing protein 2 (SMYD2), a lysine methyltransferase, is reported to catalyze the methylation of lysine residues on histone and non-histone proteins. As a potential target for cancer therapy, there are several SMYD2 inhibitors are reported, LLY-507 as a cell-active inhibitor exhibits submicromolar potency against SMYD2 in several cancer cell lines. To know which structural fragment of LLY-507 is suitable for chemical modification, three sites are chosen for structure-activity relationship studies (SARs). Among our focused library, compounds 43 and 44 with amide link on site C showed reasonably improved potency indicating that modification on this fragment is more flexible and introduction of electrophilic warheads in this position might provide lysine-targeting covalent inhibitors for SMYD2.