Insulin rescues PI3K inhibitor-induced growth suppression and signaling, 667 cells were treated with 0.5 μM BKM-120 (A) or 0.4 μM GDC-0084 (B) along with 10 ng/µL insulin, and cell proliferation was measured by Cell Titer Glo assay. (C) 667 cells were treated with 0.25 μM BKM-120 along with 20 μg/mL insulin, and PI3K-mTOR signaling was analyzed by western blot. (D) The glioma cells 308, 810, and 1228 were treated with 0.25 μM GDC-0084 along with 10 μg/mL insulin, and PI3K-mTOR signaling was analyzed by western blot. **P < .01, ***P < .001, ****P < .0001.