Fig. 4

Effects of honokiol and temozolomide (TMZ) on autophagy of human U87-MG glioma cells. Human U87-MG cells were exposed to 40 μM honokiol for 24, 48, and 72 h (a) and to honokiol (40 μM), TMZ (100 μM), and their combination for 72 h (b). Cell autophagy was analyzed by flow cytometry. Cells were pretreated with 1 mM 3-methyladenine (3-MA), an inhibitor of cell autophagy, for 1 h and then exposed to honokiol (40 μM), TMZ (100 μM), and their combination for 72 h. Cell autophagy (c) and cell apoptosis (d) were quantified by flow cytometry. Each value represents the mean ± SEM for n = 6. *, ^#, and ⁺, values significantly (p < 0.05) respectively differ from the control, TMZ-, and honokiol+TMZ-treated groups