Engineered nanoparticles to enhance natural killer cell activity towards onco-immunotherapy: a review.

Natural killer (NK) cells have emerged as a potent alternative immunotherapeutic approach to T cell therapy for cancer. Despite promising results from preclinical and clinical studies, numerous challenges have limited the application of NK cell-based therapy, including poor expansion of NK cells in vitro, their short in vivo life span, time-intensiveness, treatment complexities, and the cost burden of the treatment. Recent advancements in the development of immune cell-delivering nanosystems have led to promising strategies to overcome these limitations and enhance NK cell toxicity towards cancer cells. This review first summarizes the biological roles of NK cells and their tumoricidal mechanisms. NK cells, in the context of the immune system and the tumor microenvironment, have reportedly provided novel insights into specific therapeutic targets. Eventually, various strategies targeting NK cells using nanoplatforms to modulate the NK cell responses for effective cancer immunotherapy are described herein. Altogether, this review discusses the potential of nanotechnology in advancements in NK cell-based onco-immunotherapy.