Fig. 3.

Activation of proapoptotic pathways by C-DIMs in colon cancer cells. (A) C-DIMs decreased cell survival rates. RKO and SW480 cells were treated with various C-DIMs (15 μM) or DMSO (D) for 24 h and cell viability was measured with WST-1 assay as described in Materials and Methods. Results are expressed as means ± SDs for three replicate determinations for each treatment group and significantly (P < 0.05) decreased activity is indicated by *. Cell survival for DMSO treatment was set at 100%. Activation of PARP and caspase cleavage, induction of GRP78, DR5 and CHOP and phosphorylation of JNK in RKO and SW480 cells treated with 15 μM C-DIM analogs for 24 h (B) and comparison of DIM-C-pPhBr, DIM-C-pPhF with the classical ER stress activators, Tg and Tm (C). Colon cancer cells were treated with 15 μM C-DIMs, 10 μM Tg and 10 μg/ml Tm for 24 h and whole-cell lysates were analyzed by western blot as described in Materials and Methods. (D) Effects of caspase inhibitors on DIM-C-pPhBr-induced PARP cleavage in RKO cells. Cells were pretreated with 10 μM Z-IETD-FMK or Z-VAD-FMK for 1 h and then cotreated with DIM-C-pPhBr for 24 h. Whole-cell lysates were analyzed by western blot analysis as described in Materials and Methods.