Comparing the effects of GGTI-DU40 and SN-DU40 on modulation of DR5, DR4 and c-FLIP ( A ), on decreasing cell survival ( B ), and on TRAIL-induced apoptosis ( C and D ) in human NSCLC cells. A and D, The indicated cell lines were treated with the given concentrations of GGTI-DU40 or SN-DU40 for 8 h (A) or with DMSO, 10 μM GGTI-DU40 or SN-DU40 alone, 20 ng/ml TRAIL alone of the combination of TRAIL with GGTI-DU40 or SN-DU40 for 6 h (D). The cells were then subjected to preparation of whole-cell protein lysates and subsequent Western blot analysis for the proteins as indicated. CF, cleaved form. B and C, The indicated cell lines were seeded in 96-well plates and treated with the given concentrations of GGTI-DU40 or SN-DU40 (B) or with 20 ng/ml TRAIL alone, the given concentrations of GGTI-DU40 or SN-DU40 alone, or the combination of GGTI-DU40 or SN-DU40 with TRAIL (C). After 3 days (A) or 24 h (C), the cells were subjected to the SRB assay for measurement of cell number. Data are means of four replicate determinations. Bars, ± SDs.