CASP3 and glioblastoma: Overall, the responsiveness of the GBM cell line panel to TMZ/TRAIL treatment was improved when compared to the single agent treatments (Figure 4A, Figure 2D); this reduction in cell viability (Figure 4A) correlated with an increase in apoptotic cell death in TMZ and TRAIL-treated U251 cells, as evidenced by PARP cleavage and the prevention of such cleavage upon caspase inhibition (Supplementary Figure S1C), a significant increase in the number of Hoechst-labelled condensed nuclei (Supplementary Figure S1D), and caspase-3 substrate cleavage (Supplementary Figure S1E).