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. 2023 Feb 27;11(2):e006130. doi: 10.1136/jitc-2022-006130

Figure 5.

Figure 5

CAF-secreted IL-6 impeded NK cytotoxic function. (A–C) The effect of exogenous treatment with IL-6 in Capan2-Luc cells alone (A) and in coculture of Capan2-Luc with PBNK (B) or NK92 (C). For the luminescence-based tumor killing assay, nanoLuc luciferase-expressing Capan2 (Capan2-Luc) cells were generated. (**p<0.01) (B, C) PBNK or NK92 cells were cocultured with Capan2-Luc cells at a 10:1 or 2:1 ratio for 24 hours. (****p<0.0001) (D) The effect of the suppression of IL-6 on the activation of NK cells was investigated in the coculture of Capan2 with PBNK. Prior to coculture, PBNK cells were pretreated with CM from mock-, nintedanib-, and nintedanib plus αIL-6-treated CAFs for 24 hours. CAF-derived IL-6 attenuated the activation of NK cells. (E) IL-6-mediated signal transduction pathways in PBNK were validated under the treatment of IL-6 (100 ng/mL) with or without anti-IL-6 antibody (100 ng/mL) for 2 hours. (F) PBNK cells in the presence or absence of αIL-6 were incubated with CM from mock-, and nintedanib-treated CAFs for 2 h, and then the activation of STAT3 was detected by western blotting analysis. (G) Expression of CD69 on Jurkat T cells on treatment of CAF-derived CM in the presence or absence of nintedanib. Quantitative data were obtained from N=4 per group. (****p<0.0001) CAF, cancer-associated fibroblast; CM, conditioned media; NK, natural killer; PBNK, peripheral blood mononuclear cell-derived NK.