Fig. 1

TL32711 interacts synergistically with Btz to induce apoptosis in both Btz-naïve MM cells and Btz-resistant MM cells. a–b Btz-naïve U266 cells or Btz-resistant PS-R cells were exposed to the indicated concentrations of Btz +/− TL for 24 h (U266) or 48 h (PS-R), followed by flow cytometric analysis of cell death after staining with 7-AAD. c U266 and PS-R cells were exposed (24 h or 48 h) to varying concentrations of Btz +/− TL at a fixed ratio (1:100 or 1:30), after which the percentage of annexin V+ cells was determined. Median dose-effect analysis was then employed to characterize the nature of the interaction between these agents with constant ratio. The fraction affected (FA) less than 1.0 reflect synergistic interactions. The results are representative of three separate experiments. d U266 and PS-R cells were incubated with Btz +/− TL for 24 h or 48 h, after which γH2A.X and cleavage of Caspase-3 and PARP were monitored by immunoblotting analysis. CF, cleavage fragment. β-actin was assayed to ensure equivalent loading and transfer. **P < 0.01; ***P < 0.001