PI3Kα-IN-14 (compound F8) is a selective PI3Kα inhibitor with an IC 50 of 0.14 nM. PI3Kα-IN-14 induces a great decrease in mitochondrial membrane which caused cell cycle arrest at G1 phase and apoptosis in U87-MG cells. PI3Kα-IN-14 shows significant anti-proliferative activities against three tumor-derived cell lines (PC-3: IC 50 of 0.28 μM; HCT-116: IC 50 of 0.57 μM; and U87-MG: IC 50 of 1.37 μM).