Loss of HDAC protein expression in SFN-treated cells. (A) HCT116 cells were treated as described in Figure 1 legend, except that five replicate plates were used for SFN and vehicle, respectively, and 36 h later class I HDACs were immunoblotted in whole cell lysates. Loading control, β-actin. HeLa nuclear extract was included as a reference. Right panel: HDAC expression normalized to β-actin (mean ± SE, n = 5), ***P < 0.001 for SFN versus the corresponding vehicle control. (B) Concentration-dependent loss of HDAC2 and HDAC3, 24 h post-SFN treatment. (C) Expression of class I and selected class II HDACs at 6-h post-SFN exposure. (D) Transient overexpression of HDAC6 and HDAC3 in HCT116 cells blocks tubulin hyperacetylation and/or histone H4K12 acetylation (H4K12ac) induced by SFN. Results are representative of the findings from two or more experiments.