Fig. 4.

CHOP-dependent induction of DR5 by DIM-C-pPhBr, DIM-C-pPhF and Thapsigargin in RKO cells. (A) DIM-C-pPhBr and Tg induced transactivation in RKO cells transfected with pDR5 constructs. Cells were transfected with pDR5-Luc construct and then treated with 10–15 μM DIM-C-pPhBr or 5–10 μM Tg for 24 h. Whole-cell lysates were analyzed for luciferase activity as described in Material and Methods. Results are expressed as means ± SDs for three replicates for each treatment group and significant (P < 0.05) induction is indicated by an asterisk. (B) Increased CHOP recruitment to the DR5 promoter as determined in a chromatin immunoprecipitation assay. Cells were treated with 15 μM DIM-C-pPhF, DIM-C-pPhBr or 5 μM Tg for 12 or 24 h, and recruitment of CHOP to the DR5 promoter was determined by chromatin immunoprecipitation assay as described in Materials and Methods. The interaction of TFIIB with the glyceraldehyde-3-phosphate dehydrogenase (GAPDH) promoter but not genomic DNA between the GAPDH and chromosome condensation-related SMC-associated protein 1 genes served as positive and negative controls for the chromatin immunoprecipitation assay.