Non-small cell lung cancer (NSCLC) remains a leading cause of global mortality, necessitating novel therapies. This study investigated the therapeutic role of natural killer cell-derived exosomes (NK-Exo), whose antitumor mechanisms are incompletely understood. Exosomes were isolated from interleukin (IL)-2-independent NK-92MI cells via differential ultracentrifugation and characterized by nanoparticle tracking, electron microscopy, and western blotting. They exhibited cup-shaped morphology (50–150 nm), expressed CD81/TSG101, and demonstrated selective cytotoxicity against tumor cells (A549, A375) but not nontumor cells (293 T) in vitro; this effect was corroborated in patient-derived lung organoids. Small RNA sequencing revealed miR-140-3p as highly enriched in NK-Exo, and its expression correlated with improved survival in patients with NSCLC. Functional validation showed that overexpressing miR-140-3p enhanced NK-Exo cytotoxicity and directly inhibited cancer cell migration and invasion, whereas inhibiting miR-140-3p promoted tumor growth. Mechanistically, miR-140-3p directly targeted xylosyltransferase 1 (XYLT1), as confirmed by dual-luciferase assay, leading to reduced levels of heparan sulfate proteoglycan 2 (HSPG2). Knockdown of XYLT1 phenocopied the tumor-suppressive effects of miR-140-3p, while supplementation with heparan sulfate reversed them. In a Lewis lung carcinoma mouse model, intratumoral delivery of NK-Exo, miR-140-3p mimic, or XYLT1 Small interfering RNA (siRNA) significantly inhibited tumor growth and alleviated splenomegaly. In conclusion, NK-Exo deliver miR-140-3p to suppress tumors via the novel miR-140-3p/XYLT1/HSPG2 axis, presenting a promising therapeutic strategy for cancer.
Li et al. (Sat,) studied this question.