Fig. 4

The hNK cells with higher GPX4 expression showed resistance to L-KYN induced ferroptosis. A The percentage of FVD⁺ freshly isolated hNK cells (primary hNK cells) after being stimulated with 200 μm L-KYN for 48 h in vitro, detected by flow cytometry (the left two columns of the diagram). Then the survival hNK cells were expanded in vitro (SE-hNK cells) and stimulated with L-KYN again. The proportion of FVD⁺ cells was also detected by flow cytometry (the right two columns of the diagram). B and C The flow cytometric analysis for the MFI of MitoSox, LiperFluo and FerroOrange in the primary and SE- hNK cells (B), or the proportion of FVD⁺ NK-92 cells (C) as in Fig. 4A. D The expression of GPX4 in the FVD⁻ or FVD⁺ primary hNK cells when stimulated with L-KYN for 48 h, analyzed by flow cytometric. The pictures on the left were representative flow cytometric results. E The expression of GPX4 in the SE-hNK cells compared with the primary hNK cells, detected with flow cytometry. F The intracellular GSH level measured in the whole cell lysates of primary or SE- hNK cells. G The SE-hNK cells were stimulated with or without L-KYN at the presence of GPX4-IN-3 for 48 h. Then the percentage of FVD⁺ cells was measured by flow cytometry. All the results were replicated in 3 (A, B, D, E, F, G) or 4 (C) independent experiments. * p < 0.05, ** p < 0.01, *** p < 0.001