Effect of single and combination treatments on cell survival in a panel of GBM cells. (A–C) The characteristics of TMZ-sensitive cells were observed at 72 h post treatment, (D–F) whereas birinapant-sensitive cells at 96 h post treatment. (G) For combination treatments, additional reduction in cell survival were evident at 48 h post treatment in cells that were sensitive to TMZ and birinapant single treatment, (H) and at 72 h post treatment in TMZ- or birinapant-sensitive cells. (I) Three of the GBM cells that were resistant to single treatments had benefited from combined treatments. (J) Four of the GBM cells remained resistant to the treatments. One-way ANOVA, *P<0.05, **P<0.01, ***P<0.001.