ErPC induces growth arrest and apoptosis in human malignant glioma cell lines. T98G, A172 and U87MG were treated with 0, 12.5, 25, 50, 75 or 100 μM ErPC for 24 h, 48 h and 72 h as indicated. Subsequently, induction of apoptosis and necrosis was analyzed by fluorescence microscopy upon combined staining with Hoechst33342 and propidium iodide (PI). Apoptotic and necrotic cell death was quantified by counting cells with apoptotic and necrotic morphology. The percentage of viable cells was calculated from the difference of total cell count (= 100%) and apoptotic (% apoptosis) plus necrotic cells (% necrosis) (% viable cells = 100% – (% apoptosis + % necrosis). While 25 to 50 μM ErPC were sufficient to induce growth arrest and apoptosis in T98G and A172 cells, 75 to 100 μM ErPC were required to induce similar effects in U87MG cells. Data show one representative of three independent experiments (A) or means ± s.d., n = 3 (B, C, D, E). (A) Morphologic appearance of human malignant glioma cell lines 48 h after treatment with the indicated ErPC-concentrations. (B) Time-dependent decrease in the amount of viable cells upon treatment with 50 μM ErPC. (C, D, E) Concentration-dependent decrease in the amount of viable (C) T98G (D) A172 and (E) U87MG cells upon ErPC-treatment.