Effect of DMNB on TRAIL-induced cytotoxicity and apoptosis. PC3 (A) and KM12 (B) cells were treated with the indicated doses of TRAIL in the presence or absence of DMNB (1, 5, or 10 μM), and cell survival was determined after 96 h of incubation using the MTT assay (left). PC3 and KM12 cells were treated with the indicated doses of TRAIL in the presence or absence of 5 μM DMNB for 6 or 8 h, respectively. Thereafter, the percentage of apoptotic cells was determined using Annexin V staining and flow cytometry (right). Each point is the average of triplicate determinants. *p < 0.05, **p < 0.01, ***p < 0.001.