Fig. 3

SFN attenuated IFN-γ-induced PD-L1 expression on tumor cells. A A549 cells were treated with SFN at different concentrations. After 24 h, the cells were collected and stained with Annexin-V in a binding buffer. Then, apoptosis was tested by flow cytometry after the addition of propidium iodide. B A549 cells were treated with IFN-γ at various concentrations for different time periods. PD-L1 expression was investigated by flow cytometry. C, D A549 and H322 cells were treated with or without IFN-γ and SFN for 24 h, and PD-L1 expression was tested by flow cytometry. E, F Western blot was performed to detect PD-L1 expression after the cells were treated with IFN-γ or SFN. G–J A549 and H322 cells were incubated with meso CAR-T cells at various effector to target (E:T) ratios (1:1, 1:5, 1:10) for 24 h, and PD-L1 expression on tumor cells was examined by flow cytometry (G,I). A549 and H322 cells were incubated with meso CAR-T cells at a 1:1 ratio and were additionally treated with SFN. After 24 h, PD-L1 expression was tested by flow cytometry (H, J). Results are representative of five independent experiments. *, P < 0.05; **, P < 0.01; ***, P < 0.001; ****, P < 0.0001 (Student’s t test)