Combination effects of DMNB and TRAIL on DNA-PKcs/Akt molecules and caspase activity. (A) PC3 cells (left) and KM12 cells (right) were treated with the indicated doses of TRAIL in the presence or absence of 5 μM DMNB for 6 or 8 h, respectively, and assessed using Western blot analysis to monitor the protein levels of DNA-PKcs, pAkt and tAkt. The activation of caspases and Bax and the cleavage of PARP in cells treated with TRAIL and/or DMNB were determined by Western blot analysis. Actin was used as a loading control. (B) PC3 and KM12 cells were treated with 1 ng/ml TRAIL in the presence or absence of 5 μM DMNB for 2 h, and then incubated with an anti-DR5 antibody (1:100), and subsequently labeled with FITC-conjugated secondary antibodies (1:200) to determine the surface expression of DR5. Mouse IgG was used as an isotype control. The shaded and unshaded peaks correspond to control and specific staining, respectively.