[Research progress on umbilical cord mesenchymal stem cells combined with CAR-NK cells in tumor immunotherapy].

Chimeric antigen receptor natural killer (CAR-NK) cell therapy has shown broad prospects in the field of tumor immunotherapy, owing to its advantages such as low immunogenicity, "off-the-shelf" preparation and a good safety record. However, in the treatment of solid tumors, it faces core challenges including insufficient in vivo persistence, low homing efficiency, and immunosuppression within the tumor microenvironment (TME). Umbilical cord mesenchymal stem cells (UC-MSCs) have unique abilities in immune regulation, paracrine secretion, and remodeling of the TME, providing a new strategy for overcoming the limitations of CAR-NK cell therapy. This review summarizes the recent research progress on both CAR-NK cells and UC-MSCs in tumor immunotherapy. It further discusses the synergistic mechanism and experimental evidence supporting the combination of UC-MSCs with CAR-NK cells, and analyzes the challenges and development prospects of this method as a new tumor immunotherapy.