Neutrophil extracellular traps promote growth of lung adenocarcinoma by mediating the stability of m6A-mediated SLC2A3 mRNA-induced ferroptosis resistance and CD8(+) T cell inhibition

Abstract

To investigate the potential mechanisms underlying neutrophil extracellular traps (NETs) confer ferroptosis resistance and CD8(+) T cell inhibition in lung adenocarcinoma (LUAD). By the intravenous injection of LLC cells into the tail vein, a LUAD mouse model was created. Phorbol-12-myristate-13-acetate (PMA) stimulated neutrophils to facilitate NETs formation and combined with NETs inhibitor DNase I to explore NETs mechanism on LLC cell proliferation, migration, ferroptosis resistance, and CD8(+) T cell activity. CitH3, myeloperoxidase (MPO), cell-free DNA, and MPO-DNA levels in LUAD were increased, indicating an increase in NETs formation in LUAD. PMA promoted NETs formation in tumours of mice, increased the number of CD3(+)CD4(+) T cells, decreased perforin, granzyme A, granzyme B, IFNγ, and TNF-α levels, and promoted LUAD growth and the number of lung tumour nodules, indicating that PMA promoted NETs formation, reduced the activity of CD8(+)T cells, and promoted LUAD growth. DNase I partially reversed the effects of PMA. NETs promoted LLC cell proliferation and migration, while DNase I reversed NETs effects. Erastin inhibited LLC cell proliferation and migration and promoted ferroptosis. NETs partially reversed Erastin effects. Further results showed that NETs promoted LLC cell proliferation and migration and inhibited ferroptosis by promoting YTHDF2-mediated SLC2A3 mRNA degradation. Sh-YTHDF2 partially reversed the effect of NETs on LLC cells, whereas si-SLC2A3 partially reversed sh-YTHDF2 effects on LLC cells. In addition, NETs inhibited LLC cell ferroptosis by inhibiting CD8(+) T cell activity. Sh-YTHDF2 and DNase I inhibited NETs formation in tumours, increased the activity of CD8(+) T cells and inhibited LUAD growth. Our results suggested that NETs promoted the growth of LUAD through inhibiting ferroptosis and CD8(+) T cell activity by promoting YTHDF2-mediated SLC2A3 mRNA degradation.

Keywords: SLC2A3; lung adenocarcinoma; m6A; neutrophil extracellular traps; tumour immune microenvironment.