Effect of SFN on the total activity and protein expression of HDACs in JB6 P+ cells. Effect of SFN on the total activity and protein expression of HDACs in JB6 P+ cells. Cells (1 × 105/10-cm dish) were incubated with various concentrations of SFN (0–5.0 μmol/L) for 5 days. A, SFN inhibited total HDAC activity; the nuclear fraction was isolated and analyzed for total HDAC activity, as described in Materials and Methods. B, SFN decreased HDAC protein expression. The proteins were resolved by SDS-PAGE and Western blotting, as described in Materials and Methods. The expression of HDAC1, HDAC2, HDAC3, and HDAC4 proteins were detected by hybridization with specific antibodies. The relative expression levels were quantified based on the signal intensity of the corresponding bands and normalized using β-actin. The graphical data are presented as the mean ± SD from 3 independent experiments. * and # represent P < 0.05 and P < 0.01, respectively, which indicate significant differences in each target protein compared with its level in non-SFN-treated cells. Zheng-Yuan Su et al. Cancer Prev Res 2014;7:319-329 ©2014 by American Association for Cancer Research