Fig. 4

Influence of PI3K inhibitor to IL-7-mediated CD8⁺ T cell cytotoxicity in patients with primary cutaneous melanoma. Purified peripheral CD8⁺ T cells (nine HLA-A02 restricted patient with primary cutaneous melanoma and six HLA-A02 restricted healthy individuals) and tissue-infiltrating CD8⁺ T cells (tumor and para-tumor tissues of six HLA-A02 restricted melanoma patients) were stimulated with recombinant human IL-7 (10 ng/mL) and PI3K inhibitor (25 µmol/L) for 48 h in the presence of anti-CD3/CD28. Cells were washed twice, and 10⁴ of stimulated CD8⁺ T cells were co-cultured with 10⁵ of SK-MEL-5 cells for another 48 h. The percentage of target cell death was calculated by measurement of LDH level in the supernatants. IFN-γ and TNF-α level in the supernatants was measured by ELISA. Inhibition of PI3K dampened the cytotoxicity of a peripheral CD8⁺ T cells from melanoma patients and controls, as well as b tissue-infiltrating CD8⁺ T cells from tumor tissues and para-tumor tissues. Inhibition of PI3K inhibitor suppressed IFN-γ secretion by c peripheral CD8⁺ T cells from melanoma patients and controls, as well as d tissue-infiltrating CD8⁺ T cells from tumor tissues and para-tumor tissues. Inhibition of PI3K inhibitor also suppressed TNF-α secretion by e peripheral CD8⁺ T cells from melanoma patients and controls, as well as f tissue-infiltrating CD8⁺ T cells from tumor tissues and para-tumor tissues. Individual level of each subject is shown. Statistical analysis was performed using one-way ANOVA and LSD-t test