NK-derived exosomes in anti-tumor strategies.

Tumors remain one of the major challenges confronting researchers today. The development of tumor is driven by genetic factors, environmental exposures, and homeostatic disruptions, leading to the transformation of normal cells into malignant ones. Natural killer (NK) cells, a crucial class of immune cells in immunotherapy, can directly recognize and eliminate tumor cells without prior stimulation by tumor antigens. Exosomes derived from NK cells exert anti-tumor effects through multiple mechanisms, including the release of cytotoxic molecules, death receptor ligand-mediated apoptosis, and the secretion of cytokines and other bioactive molecules. However, the therapeutic efficacy of unmodified exosomes is constrained by insufficient active components, suppression by the tumor microenvironment, and a lack of targeting specificity. Drug loading and engineering strategies can enhance their therapeutic potential. In this review, we examine advancements in NK cell-derived exosome (NK-Exos)-based anti-tumor strategies, focusing on studies involving native exosomes, drug-loaded exosomes, and surface-modified exosomes for tumor eradication.