Figure 1. Combined treatment with the BH3-mimetic ABT263 and the ERK inhibitor TIC10/ONC201 yields a synergistic antiproliferative effect across different glioblastoma cells.

A. SF188 (pediatric), T98G (adult) and MGPP-3 (murine, transgenically derived) glioblastoma cells were treated with the indicated concentrations of TIC10/ONC201 or ABT263 under serum starvation (1.5% FBS). After 72 h, a MTT assay was performed. Graphs were plotted using the CompuSyn software. B. The antiproliferative effect of ABT263 and TIC10/ONC201 was assessed by an MTT assay after 72 h of treatment with the single agents or the respective combination at indicated concentrations under serum starvation (1.5% FBS). Normalized isobolograms were calculated using the CompuSyn software. The ED₅₀ values of TIC10/ONC201 and ABT263 are normalized and plotted on the x- or y-axis. The connecting line represents additivity. Data points located below the line indicate a synergistic drug-drug interaction and data points above the line indicate an antagonistic drug-drug interaction. C. Representative microphotographs of SF188 and MGPP-3 glioblastoma cells treated with solvent, ABT263, TIC10/ONC201 or both for 48 h at indicated concentrations. Magnification, x20; scale bar, 100 μm. D. 3-dimensional representation of the chemical structures of TIC10/ONC201 and ABT263.