B MEFs (upper panel) and CCRF-CEM cells (lower panel) were pretreated with 20 μM DMSO, 1 μM MG132, 0.02 μM Concanamycin A (Conc A), 20 μM Calpeptin (Calp), or 20 μM Z-VAD-FMK (Z-VAD) for 2 hours, followed by 16-hour ATO co-treatment at 1 μg/mL for MEFs or 0.3 μg/mL for CCRF-CEM cells. Immunoblotting of DNMT3A in whole cell lysate is shown. 