Figure 7

Blockage of DR5 induction abrogates augmented induction of apoptosis by GGTI-298 and TRAIL combination ( A ), whereas inhibition of DR4 induction sensitizes cells to GGTI-298 plus TRAIL-induced apoptosis ( A -C). A and B, A549 cells were cultured in a 6-well plate and the next day transfected with the indicated siRNAs twice in a 24 h interval. Twenty four hours after the second transfection, cells were treated with 15 μM GGTI-298 plus 20 ng/ml TRAIL (A and B, right panel) or 15 μM GGTI-298 only (B, left panel) for 8 h and then subjected to preparation of whole-cell protein lysates for Western blotting (A and B, left panels) or detection of apoptosis by Annexin V staining (A and B, right panels). C, H157 cells were cultured in a 6-well plate and the next day transfected with the indicated siRNAs twice in a 24 h interval. Twenty four hours after transfection, the cells were treated with 15 μM GGTI-298, 20 ng/ml TRAIL or GGTI-298 plus TRAIL. After 8 h (left panel) and 24 h (right panel), the cells were harvested for preparation of whole-cell protein lysates for Western blotting (left panel) or for detection of apoptosis by the Annexin V staining (right panel), respectively. Data are means of duplicate experiments; Bars, ± SEs. Ctrl, control; GGTI, GGTI-298; G + T, GGTI-298 plus TRAIL; CF, cleaved from.