Fig. 6.

GRP78 knockdown activates the UPR and sensitizes cells to TRAIL-induced apoptosis. a Cell lysates from MDA-MB231 cells transfected with siRNAs (50 nM) for 48 h were analyzed for protein expression as described in “Materials and methods” section. b MDA-MB231 cells were transfected with 50 nM GRP78 siRNA or a scrambled (control) siRNA for 48 h as described in “Materials and methods” section. XBP1s and CHOP mRNA levels were determined by RT-PCR and β-actin was used as a control for mRNA input. Results are representative of at least two independent experiments. c MDA-MB231 or HeLa cells were transfected with siRNAs for 48 h and treated with TRAIL (500 ng/ml) for 24 h. Apoptosis was assessed as the percentage of hypodiploid cells. Error bars represent S.D. from three independent experiments. *P <0.05, **P <0.01. d MDA-MB231 cells transfected with siRNAs (50 nM) for 48 h were incubated with or without TRAIL for 24 h in the presence or absence of Z-VAD-fmk. Hypodiploid cells were determined as described under “Materials and methods” section. Error bars represent S.D. from three independent experiments. **P <0.01