Figure 2
ABT-737 synergizes with TRAIL to trigger caspase-dependent apoptosis. (a) U87MG (left panel) and U118MG (right panel) cells were treated for indicated times with 5 ng/ml (U87MG) or 10 ng/ml (U118MG) TRAIL and/or 5 μM ABT-737. Apoptosis was determined by FACS analysis of DNA fragmentation of propidium iodide-stained nuclei. Data represent mean±S.E.M. of three independent experiments performed in triplicate (**P<0.001). (b) U87MG (left panel) and U118MG (right panel) cells were treated for indicated times with 5 ng/ml (U87MG) or 10 ng/ml (U118MG) TRAIL and/or 5 μM ABT-737. Caspase activation was analyzed by western blotting; arrowheads indicate caspase cleavage fragments. A representative experiment of three independent experiments is shown. (c) U87MG (left panel) and U118MG (right panel) cells treated for 24 h with 5 ng/ml (U87MG) or 10 ng/ml (U118MG) TRAIL, 5 μM ABT-737 and/or 20 μM zVAD.fmk. Cell viability was determined by MTT assay and is expressed as percentage of untreated controls. Data represent mean+S.E.M. of three independent experiments performed in triplicate. (d) U87MG cells were treated for 12 h with 5 ng/ml TRAIL and/or 5 μM ABT-737 in the presence or absence of 20 μM zVAD.fmk. Colonies were stained with crystal violet after 18 days and were counted under the microscope. One representative experiment (right panel) and the percentage of colony numbers compared with untreated control are shown (left panel). Data represent mean+S.E.M. of three independent experiments (**P<0.001)
