Effects of casticin on TRAIL-induced apoptosis in gastric cancer cells.

Casticin enhanced TRAIL-induced apoptotic cell death measured using flow cytometric analysis (A and B), cell apoptosis ELISA detection kit (C and D) in BGC-823, SGC-7901, and MGC-803 cells (mean±SD, n=3). ^*P<0.05 vs. treatment with DMSO or 0 h; ^#P<0.05 vs. treatment with 1 µmol/l casticin or TRAIL at the same concentration alone for 6 h. The enzymatic activities of caspase-3(E), -8(F), and -9(G) were determined by incubation of 20 µg of total protein with 200 µM chromogenic substrate (Ac-DEVD-pNA or Ac-IETD-pNA or Ac-LEHD-pNA) in 100 µl assay buffer for 2 h at 37 °C. The release of chromophore p-nitroanilide (pNA) was monitored by a spectrophotometer (405 nm). Data shown are the mean±S.D (n = 3). * p<0.01 vs. 0.1% DMSO; # p<0.05 vs. treatment with casticin and TRAIL alone. The cleavage of PARP was examined by western blotting analysis in BGC-823 and SGC-7901 cells (H).