Indeed,in enzymatic assays, compound 8a displayed more than18-fold HDAC3 selectivity over other class I HDACs, while more than3000-fold selectivity over HDAC4–6. In biological assays performed on the B16–F10 murine melanomacell line and the 4T1 murine breast cancer cell line, compound 8a showed high cytotoxic effects, whereas less cytotoxicitytoward healthy human cell lines was observed. Here, HDAC3 is linked to breast cancer.