Fig. 4

Combined treatment-induced cell death was inhibited by anti-TRAIL antibody and pan-caspase inhibitor. (a) After the pre-treatment of anti-TRAIL antibody (1 μg/ml) for 1 h, B16F10 and CT26 cells were treated with the indicated amount of bortezomib (50 nM) and varying amounts of ILz:rhTRAIL: ILz:T, ILz:rhTRAIL; bort, bortezomib; anti-T, anti-TRAIL antibody. Cell death was analyzed by XTT assay 24 h after treatment. (b) B16F10 and CT26 cells were cultured onto a 96-well plate and treated with ILz:rhTRAIL (100 ng/ml) and bortezomib (100 nM) with or without z-VAD-fmk (50 μM) pre-treatment for 1 h. After 24 h, cell death was assayed by XTT: ILz:T, ILz:rhTRAIL; bort, bortezomib; z-VAD, z-VAD-fmk. *p < 0.05 by Student’s t-test. (c) B16F10 cells were stained with propidium iodide (PI) and Annexin V using FITC Annexin V Apoptosis Detection Kit (BD Biosciences). Cells were harvested after trypsin treatment and the stained populations were analyzed by Flow cytometry (FACSCalibur™, BD Biosciences, US) using BD CellQuest™ program. The populations (%) are marked in the figures