Overexpression of Bcl-XL inhibits the caspase-3-like protease activation and induction of apoptosis caused by CDDP treatment. (A) Western blot analysis showing expression levels of Bcl-XL in U87MG Bcl-XL-overexpressing clones (Bcl-XL-6, -9, -13, -11, -12, and -8) and empty vector-transfected clones (SFFV-2 and -5). U87MG and U87MG.ΔEGFR cells were treated with 5 μg/ml of CDDP for 2 days. For each sample, 20 μg total cell lysate was used. (B) Caspase-3-like protease activity of the Bcl-XL-overexpressing clones 2 days after treatment with 5 μg/ml CDDP measured as described in Fig. 4A. Values are means of two to six independent experiments. (Bars = SE.) (C) Apoptosis rate of Bcl-XL-overexpressing clones 2 days after treatment with 5 μg/ml of CDDP determined by TUNEL assay. Values represent means from two to three independent experiments in triplicate. (Bars = SE.)