Cell pellets were lysed with RIPA buffer (150 mM sodium chloride, 1% NP-40, 0.5% sodium deoxycholate, 0.1% SDS, 50 mM Tris pH 8.0) plus protease inhibitor (cat. no. P8340) and phosphatase inhibitor (cat. no. P5726; both Sigma-Aldrich; Merck KGaA) at recommended rates. Western blotting was conducted as described previously (20 (link)). Total protein was determined using a BCA assay (Bio-Rad Laboratories, Inc.). Blocking of membranes was performed at room temperature for 1 h; primary antibody incubations were performed overnight at 4°C, with secondary antibody incubations performed at room temperature for 1 h. Labelled bands were detected by Clarity ECL kit (Bio-Rad Laboratories, Inc.) and images were captured by the ChemiDoc MP Bio-Rad image system. Antibodies directed against HDAC6 (1:1,000; cat. no. 7558), DNMT3a (1:1,000; cat. no. 3598), DNMT3b (1:1,000; cat. no. 67259) and enhancer of zeste homolog 2 (1:2,000; EZH2; cat. no. 5246) were purchased from Cell Signaling Technology, Inc. Anti-β-actin antibody (1:3,000; cat. no. AC-74) was acquired from Sigma-Aldrich (Merck KGaA). The secondary antibodies used were horseradish peroxidase-conjugated goat anti-mouse IgG (H+L) and goat-anti-rabbit IgG (H+L) antibodies (1:3,000; cat. nos. 1706516 and 1706515; Bio-Rad Laboratories, Inc.).