To further elucidate SMYD3 function in the crosstalk between its binding partners AMPK and mTOR upon NCS exposure, we treated HCT-116 and AGS gastrointestinal cancer cells and the MDA-MB-231 breast cancer cell line with the novel active site-selective covalent SMYD3 inhibitor EM127. This evidence concerns the gene SMYD3 and breast carcinoma.