Fig. 7

Effects of chloroquine (CLQ), an inhibitor of cell autophagy, on honokiol-induced autophagy and apoptosis in human temozolomide (TMZ)-sensitive and -resistant glioma cells. Human U87-MG cells were pretreated with 20 μM CLQ for 1 h and then exposed to 40 μM honokiol, 100 μM TMZ, and their combination for another 72 h (a, b). Human TMZ-resistant U87-MG-R9 cells, selecting from human U87-MG cells and culturing in DMEM medium containing TMZ, were pretreated with 20 μM CLQ for 1 h and then exposed to 40 μM honokiol for 72 h (c, d). Cell autophagy (a and c) and apoptosis (b and d) were quantified using flow cytometry. Each value represents the mean ± SEM for n = 3. Symbols *, ^#, and ⁺, indicate the values significantly (p < 0.05) differ from the control, TMZ-, and honokiol+TMZ-treated groups, respectively