Abstract 6309: Activated neutrophils inhibit chemotactic migration of activated T lymphocytes to CXCL11 by multiple mechanisms

Abstract

Abstract Objective High density of tumor-infiltrating lymphocytes (TILs) in the tumor is associated with favorable prognosis of cancer patients, while that of tumor-associated neutrophils (TAN) shows inverse correlation with outcome. We examined the effects of activated neutrophils on chemotactic migration of activated T cells in vitro. Methods Neutrophils and mononuclear cells (PBMC) were collected from the blood of healthy donor. Neutrophils were stimulated with PMA (1uM) or LPS (10ug/ml) for 15 min, washed extensively, and incubated for another 4 hours. PBMC were cultured on anti-CD3 mAb-coated plate with recomnibant-IL-2 (10ng/ml) for 7-14days. The activated T cells were placed in culture inserts with 3μm pore and migration to CXCL-11 (1000ng/ml) placed in lower chamber with or without neutrophils was examined after 2 hours. Random migration of activated T cells on fibronectin coated plate was evaluated with timelapsed analysis using Biostudio system. Degradation of CXCL-11 was examined with western blotting. Results Neutrophils stimulated with PMA or LPS produced neutrophil extracellular traps (NETs). Migration of T cells to CXCL-11 was drastically inhibited in the presence of PMA-activated neutrophils. The inhibition was similarly detected when NETs was removed from PMA-activated neutrophils by ultracentrifugation. Timelapse analysis also showed the NET-depleted supernatant greatly inhibited random migration, which was totally canceled by the pretreatment with 800U/ml catalase. When neutrophils were activated by LPS, T cell migration was also significantly inhibited (p=0.02) but not by NET-depleted supernatant (p=0.99). In western blotting, CXCL11 was totally degraded by LPS-stimulated neutrophils, which was greatly reduced by the depletion of NET component. CXCL11 degraded by NETs was restored by protease inhibitor, 5mM phenylmethylsulfonyl fluoride (PMSF). The reduced migration induced by LPS-stimulated neutrophils was mostly restored with 2mM PMSF. Conclusion Activated neutrophils inhibit chemotactic migration of activated T cells through multiple mechanisms including ROS production and chemokine degradation. TAN may have suppressive effects on the accumulation of TILs. Citation Format: Kohei Tamura, Yuki Kaneko, Yurie Futoh, Kazuya Takahashi, Yuki Kimura, Akira Saito, Mineyuki Tojo, Hideyo Miyato, Hideyuki Ohzawa, Yasushi Saga, Yuji Takei, Hiroyuki Fujiwara, Joji Kitayama. Activated neutrophils inhibit chemotactic migration of activated T lymphocytes to CXCL11 by multiple mechanisms [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 6309.