Fig. 5

The impact of radiation therapy on NK and CAR-NK cell activity, infiltration, and antitumor cytolytic ability. Radiation therapy is key in enhancing the activity and infiltration of NK and CAR-NK cells within the tumor microenvironment. The timing of radiotherapy mediates several crucial effects: (1) Radiation promotes the expansion of natural killer (NK) cells, boosting their cytotoxic potential. (2) It activates NK cells, stimulating the secretion of effector cytokines like IFN-γ and TNF-α, strengthening their antitumor responses. (3) Radiotherapy reduces tumor burden, facilitating the infiltration of CAR-NK cells into the tumor site. (4) Radiation-induced lymphopenia creates additional space for CAR-NK cell expansion, enhancing their therapeutic efficacy. (5) Radiation also induces the release of chemokines, which attract CAR-NK cells to the tumor, optimizing their localization and activity. The synergy between radiation therapy and CAR-NK cell therapy underscores the potential of this combined approach for cancer treatment