Advances in CAR NK Cell Therapy for Targeting and Eradicating Circulating Tumor Cells: Challenges and Solutions for Aging Patients Mini Review

Chimeric Antigen Receptor (CAR) Natural Killer (NK) cells represent a promising advancement in cancer immunotherapy, particularly for targeting circulating tumor cells (CTCs) and preventing metastasis. This review examines the latest developments in CAR NK cell therapy, including diverse NK cell sources, genetic engineering techniques, and dual mechanisms of action. Targeting CTCs with CAR NK cells shows significant potential in aggressive cancers like triple-negative breast cancer (TNBC) and pancreatic cancer. The impact of aging on NK cell function, especially regarding cytotoxicity, cytokine secretion, and persistence, poses challenges for elderly patients, but strategies such as interleukin-15 and metabolic interventions offer potential solutions. The review also addresses current limitations, such as poor persistence in immunosuppressive microenvironments and low solid tumor infiltration, while proposing combination therapies to enhance effectiveness. Although still in earlier clinical stages compared to CAR T cells, CAR NK cells’ safety profile and MHC-independent recognition mechanisms make them a versatile therapeutic option. Future directions include optimizing NK cell persistence, improving infiltration, and developing age-adapted therapies for elderly patients.