Effect of Sch B on cell cycle progression in glioma cells. A. U87 and U251 cells were exposed to various concentrations of Sch B (0, 25, 50, 100 μmol/L) for 48 h and then analysed using flow cytometry. B. The percentages of the total cell population in the G0/G1, S, and G2/M phases of the cell cycle are calculated. C. Effects of Sch B on the protein levels of cyclin D1 and CDK4 in U87 and U251 cells were measured by western blot analysis, with β-actin as a loading control.