Figure 4. HDIs induced ERK1/2 activation but inhibited c-SRC and STAT3 activation in human cancer cells. UOK121, SF295 and H460 cells were treated with romidepsin (1-2-5 ng/ml) + verapamil (5 μg/mL), vorinostat (2.5-5-7.5 μM), or apicidin (1-2-5 μM) for 24 h and ERK1/2 phosphorylation, c-SRC phosphorylation and STAT3 phosphorylation were detected by western blot analysis. Protein levels were normalized to GAPDH and plotted as mean ± SD from three independent experiments. **p < 0.05, *p < 0.01 vs control value. Representative immunoblots are shown in Figure S2.