Nuclear proteins from mouse breast tumor tissues were extracted by NE-PER Nuclear and Cytoplasmic Extraction Reagents (Thermo Scientific). The HDACs activity was evaluated by EpiQuik HDAC Activity/Inhibition Assay Kit (Epigentek, Brooklyn, NY) according to the manufacturer’s protocols, respectively, as done previously (13 (link), 18 (link)). The enzymatic activities of HDACs were colorimetrically demonstrated and detected by an Epoch Microplate Spectrophotometer at 450 nm.