A novel small molecule ZYZ384 targeting SMYD3 for hepatocellular carcinoma via reducing H3K4 trimethylation of the Rac1 promoter.

SMYD3 (SET and MYND domain-containing 3) is a histone lysine methyltransferase highly expressed in different types of cancer(s) and is a promising epigenetic target for developing novel antitumor therapeutics. No selective inhibitors for this protein have been developed for cancer treatment. Therefore, the current study describes developing and characterizing a novel small molecule ZYZ384 screened and synthesized based on SMYD3 structure. Virtual screening was initially used to identify a lead compound and followed up by modification to get the novel molecules. Several technologies were used to facilitate compound screening about these novel molecules' binding affinities and inhibition activities with SMYD3 protein; the antitumor activity has been assessed in vitro using various cancer cell lines. In addition, a tumor-bearing nude mice model was established, and the activity of the selected molecule was determined in vivo. Both RNA-seq and chip-seq were performed to explore the antitumor mechanism. This work identified a novel small molecule ZYZ384 targeting SMYD3 with antitumor activity and impaired hepatocellular carcinoma tumor growth by reducing H3K4 trimethylation of the Rac1 promoter triggering the tumor cell cycle arrest through the AKT pathway.