Sch B induces apoptosis in U87 and U251 cells. U87 and U251 cells were exposed to various concentrations of Sch B for 48 h. A. Sch B treated cells were stained with annexin-V/propidium iodide (PI). The Q3 (annexin-V−/PI−), Q4 (annexin-V+/PI−) and Q2 (annexin-V+/PI+) quadrants represent the populations of normal, early apoptotic and late apoptotic cells, respectively. B. Percentages of surviving cells and early and late apoptotic cells are shown as the means ± SD (n = 3). C. Apoptotic nuclear morphological changes induced by Sch B (0, 25, 50, 100 μmol/L) for 48 h were observed using Hoechst 33342 staining in U87 and U251 cells. The arrowheads indicate apoptotic cells, which exhibited highly condensed and fragmented nuclear morphologies. D. Percentages of apoptotic cells are shown as the means ± SD (n = 3). *P < 0.05, **P < 0.01, ***P < 0.001 compared with the control group.