Figure 6.

Inhibition of autophagy enhances the antitumor effects of PI3K inhibition. A) Mice bearing ZR75-1 xenografts were randomized to treatment with vehicle (n = 7), CQ (0.288 mg/ml in drinking water; n = 7), GDC-0941 [800 mg/kg per week (QW); n = 8], or the combination (n = 8). B) Mice bearing ZR75-1/FR xenografts were treated with a fulv (5 mg QW) backbone, and randomized to vehicle (n = 5), CQ (50 mg/kg i.p. QD; n = 5), GDC-0941 [100 mg/kg per day (QD); n = 5], or the combination (n = 7). Means ± sem are shown. *P < 0.05 compared with control unless otherwise indicated with brackets. C–E) ZR75-1/FR tumors were harvested at 4 h after the final dose of GDC-0941 or CQ on d 3. Tumor sections were analyzed by TUNEL to assess apoptosis (C) and by IHC for Ki67 to assess cell proliferation (D). *P < 0.05 by Bonferroni multiple comparison–adjusted post hoc test compared with control unless otherwise indicated with brackets. Ns, not significant. E) Tumor lysates were analyzed by immunoblot using the indicated antibodies. FL, full-length; CL, cleaved. Densitometry analysis was performed on p62, LC-3-II, and vinculin. p62 and LC-3-II signal intensities were normalized to vinculin control, and data are shown as the percentage of vehicle-treated controls.