Surface‐Engineered Natural Killer Cell‐Derived Small Extracellular Vesicles Induce Potent Anti‐Tumour Effects in Lung Cancer Cells

ABSTRACT Small extracellular vesicles (sEVs) derived from natural killer (NK) cells possess inherent anti‐tumour activity and offer the advantages of cell‐free therapy. In this study, we genetically engineered NK‐sEVs to express interleukin 15 (IL15), an anti‐tumour cytokine, and the monoclonal antibody cetuximab on their surface, creating a potent anti‐tumour immunotherapy with enhanced tumour‐targeting capabilities. These IL15‐ and cetuximab‐tethered NK‐sEVs (eEVs) were generated using lentivirus‐based modification. eEVs selectively bound to EGFR + cancer cells in vitro, confirming cetuximab‐mediated targeting. Compared to control NK‐sEVs, eEVs exhibited significantly enhanced cytotoxicity by directly inducing cancer cell death and promoting NK cell‐mediated killing. In a lung cancer mouse model, eEVs selectively accumulated in tumours and exhibited significant anti‐tumour efficacy. Notably, their administration, alone or in combination with anti‐PD‐1 antibody therapy, effectively suppressed tumour growth. Overall, our results indicate that genetically engineered NK‐sEVs, equipped with IL15 and cetuximab, exhibit potent anti‐tumour activity and tumour‐targeting capabilities. These findings suggest that eEVs hold significant potential as a novel immunotherapeutic strategy for cancer treatment.