Flupentixol decreases lung cancer cell viability. (A) Flupentixol (2.5, 5, 10, 20, or 40 μM) inhibited the viability of four NSCLC cell lines (H661, A549, H520 and SK-SEM-1) in a dose-dependent manner but had little effect on BEAS-2B cells. The cells were treated with flupentixol for 24 hours, and MTT assays were performed to measure cell viability. (B) H661 and A549 cells were treated with increasing concentrations of flupentixol (2.5, 5, 10, 20, or 40 μM) for 24, 48, and 72 hours. The inhibitory effect of flupentixol in lung cancer cells was in a dose- and time-dependent manner. (C) The 24-hour cytotoxicity of flupentixol was stronger than those of two known PI3K inhibitors (BYL719 and BKM120) in A549 and H661 cells.