ErPC and radiation cooperate to induce cell death in T98G cells. T98G were irradiated with a single dose of 0, 2.5, 5 or 10 Gy and subsequently treated with 0, 12.5, 25 or 50 μM ErPC as indicated. Induction of apoptosis and necrosis was quantified 24 h, 48 h and 72 h after treatment by fluorescence microscopy counting the cells with apoptotic and necrotic morphology upon combined staining with Hoechst 33342 and PI. The percentage of viable cells was calculated as indicated in Fig.1. Data show (A) one representative of three independent experiments or (B, C, D) means ± s.d. ; n = 3. (A) Photomicrographs of morphologic appearance of T98G cells upon treatment with medium (control), 10 Gy, 50 μM ErPC or 10 Gy and 50 μM ErPC. (B) Dose dependent increase in efficacy of the combination 48 h after treatment. (C and D) Time dependent increase in efficacy of the combination.