Effect of Can on TRAIL-mediated apoptosis in prostate cancer cells. DU145 cells were treated with Can (0, 0.25, 0.50 and 1 μM) for 18 h and then with TRAIL (200 ng/ml) for an additional 2 h. (A) The morphology of DU145 cells was evaluated by interference light microscopy (scale bar=100 μm; magnification, ×100). (B) Cellular viability was assessed with crystal violet staining in DU145 cells. (C) Quantification of the average density of crystal violet staining in DU145 cells. (D) Cellular viability was evaluated with trypan blue dye exclusion assays in DU145. (E) Morphology, (F and G) crystal violet cellular viability and (H) trypan blue staining in LNCaP cells. *P<0.05, **P<0.01 and ***P<0.0001. Can, cantharidin; TRAIL, tumor necrosis factor-related apoptosis-inducing ligand.