fig2

Figure 2. Synergistic interactions between obatoclax and TRAIL require different treatment schedules. (A) Dose-response curves for obatoclax, TRAIL, or the combination following 48-h treatment of H460, A549, and SW1573 cells. (B) Synergistic activity was calculated and represented by the Combination Index (CI); CI < 0.9 = synergy, CI < 0.3 = strong synergy. (C) Cell death measurement after 48-h concurrent treatment with 2 μM obatoclax, 50 ng/mL TRAIL, or both for A549 and 0.5 μM obatoclax, 50 ng/mL TRAIL, or the combination for SW1573. (D) Measurement of cell death after 48-h obatoclax treatment followed by the addition of TRAIL for 24 h: 2 μM obatoclax, 50 ng/mL TRAIL, or the combination, for A549; and 0.5 μM obatoclax, 50 ng/mL TRAIL, or the combination for SW1573. (E) Measurement of cell death after incubation with caspase inhibitor zVAD using pre-incubation or concurrent treatment for A549 and SW1573 cells, respectively. Values are means ± SEM of at least three separate experiments. Statistics: (B) **P < 0.0001, SW1573 compared to H460 and A549; (C and D) *P < 0.01, higher sub-G1 for the combination of obatoclax with TRAIL compared to single agents; (E): P < 0.01, lower for zVAD compared to no zVAD.