Abstract

Natural Killer (NK) cells are a promising tool for adoptive cell therapy, and genetic modification is key to enhancing their therapeutic potential. This study directly compared the functional and proliferative characteristics of two engineered NK cell populations: those immortalized with human telomerase reverse transcriptase (hTERT-NK) and those incorporating an inducible Caspase 9 (iCasp9-NK) safety switch. NK cells were isolated and transduced with vectors encoding either hTERT or iCasp9. Proliferative capacity was assessed over extended culture, and functional activity was evaluated through standard cytotoxicity and degranulation assays against target cells. The hTERT-NK cells demonstrated significantly enhanced and sustained proliferative activity compared to the iCasp9-NK cells, suggesting that hTERT overexpression effectively bypasses replicative senescence. While both cell types maintained robust cytotoxic function, the hTERT-NK population exhibited a more favorable profile of activation markers and reduced expression of exhaustion markers over time. This comparative analysis provides crucial data for the rational design of next-generation NK cell therapies. The findings suggest that hTERT-mediated immortalization offers a substantial advantage in generating the large cell numbers required for clinical trials, while the iCasp9 switch remains a vital component for ensuring patient safety. Future strategies may involve combining both modifications to create a highly potent, scalable, and controllable therapeutic agent.