Fig. 4.

TRAIL-R2 plays a major role in apoptosis induced by TRAIL in ER stressed cells. MDA-MB231 cells were transfected with 50 nM TRAIL-R2 (a), TRAIL-R1 (b) or scrambled (control) siRNA (a, b) for 48 h prior to incubation in the absence or presence of tunicamycin (250 ng/ml) for 15 h. After this incubation cells were treated with or without TRAIL (500 ng/ml) for 6 h and apoptosis was determined as described in “Materials and methods” section. Error bars represent S.D. from three independent experiments. Protein knockdown was assessed by western blotting and GAPDH was used as a control for protein loading. Results are representative of at least three independent experiments