TP53 and non-small cell lung carcinoma: To determine the mode of action of BTZ-induced cell death in Onc-p53–expressing NSCLC cells, we first determined the contribution of apoptosis by testing the effect of the pan-caspase inhibitor QVD-OPh on BTZ-induced cell death of H1975 cells, and remarkably, cell death was almost completely rescued by QVD-OPh (P < 0.005; Fig. 3A).