R115777 synergizes with paclitaxel to induce cytochrome c (cyt C) and caspase-3. (A) R115777 (100 nM) synergized with paclitaxel (2 nM) in caspase-3 activation. RPMI8226/S cells were treated with drugs for 48 hours before caspase-3 and caspase-8 activities were assayed. Results represent means and standard deviation of 3 independent experiments. (B) R115777 (100 nM) synergized with paclitaxel (2 nM) in causing cytochrome c release. RPMI8226/S cells were treated with drugs for 72 hours before harvesting for Western blot analysis. (C) Effect of treatment of paclitaxel and R115777 on apoptotic and prosurvival Bcl2 family members. RPMI8226/S cells were treated with drugs at indicated concentrations for 72 hours before harvesting for Western blot analysis.