PI3K inhibitors impair normal and CLL human T-cell survival and function. (A) CellTiter-Blue assay of T-cell viability after 24 hours of treatment with the indicated concentrations of PI3K inhibitors. (B) Inhibition of PI3K signaling in normal or CLL patient CD3⁺ T cells isolated from human PBMCs was measured by assessing levels of pS473-AKT after 24 hours of incubation with inhibitors, followed by stimulation with anti-CD3/anti-CD28. Graphs display mean + standard deviation (SD) compiled from all samples; n = 3 normal donors and n = 4 CLL patient samples. (C-D) Cytokine bead array analysis of Th1/Th2 cytokines secreted from human CD3⁺ normal or CLL T cells incubated with the indicated inhibitors (1 μM, for 24 hours), following anti-CD3/anti-CD28 stimulation. (E-F) The expression of Th transcription factors was assessed by qRT-PCR in CD3⁺ T cells incubated with the indicated inhibitors (1 μM, 24 hours), followed by anti-CD3/anti-CD28 stimulation (24 hours). Graph displays ΔΔCT for each transcription factor. Data in (C-F) are representative of 3 independent experiments, using a unique donor for each experiment. Graphs display mean + SD of technical triplicates from a representative donor. *P < .05, **P < .005, ***P < .0005, ordinary 1-way ANOVA. ns, not statistically significant.