A. Combination of DS7423 and TMZ resulted in additive cytotoxicity in 3 GBM cell lines in vitro. B. and C. The combination treatment of TMZ with DS increased autophagic cell death within 24 hours in U87 cells, as shown by increased punctate GFP fluorescence at 24 hours. Data are presented as the mean ± SD of three experiments. D. Cells treated with the either DS7423, TMZ or combination of DS and TMZ. DS and TMZ combination increased LC3-11 levels in comparison to either DS or TMZ alone. E. and F. Survival increased after oral administration of DS7423, TMZ, or DS7423 + TMZ in nude mice bearing intracranial U87 xenografts. D, Kaplan–Meier survival curves comparing the treatments using log-rank tests. DS and TMZ were compared with the control group, and DS + TMZ was compared with the control group, TMZ alone, and DS alone. E, Representative H&E-stained whole brain sections at 4 weeks after treatment. Immunostaining of the brain sections of mice treated with DS7423, TMZ, and DS+TMZ for 4 weeks (n = 2). The tissue sections were incubated with antibodies against Ki-67. Bar, 100 μm.