Abstract: Natural killer (NK) cells are pivotal in immune surveillance and hold significant potential for cancer immunotherapy. Although pluripotent stem cells (PSCs), including induced pluripotent stem cells (iPSCs) and embryonic stem cells (ESCs), are emerging as promising sources for NK cell generation, the influence of PSC origin on NK cell differentiation and function remains poorly understood. Given the variability in differentiation efficiency and functional properties of PSC-derived NK cells, this study aimed to compare NK cell differentiation from various PSC sources and evaluate their cytotoxic potential for immunotherapeutic applications. We derived NK cells from iPSCs generated from CD34+, CD56+, and CD56- cells isolated from human umbilical cord blood, as well as from ESCs. Our results demonstrated that NK cells from CD34+ iPSCs (CD34+ iPSC-NK cells) exhibited superior expansion and cytotoxicity compared to those derived from CD56+ or CD56- iPSCs. ESC-derived NK cells (ESC-NK cells) displayed higher cytotoxic activity than CD34+ iPSC-derived NK cells, despite sharing similar NK receptor profiles. Further, we enhanced ESC-NK cells by introducing a chimeric antigen receptor (CAR) targeting HER2, a tumor-associated antigen. CAR ESC-NK cells significantly outperformed wild-type ESC-NK cells in cytotoxicity against HER2-positive cancer cells. Our findings highlight that ESCs represent a robust source for generating functional NK cells with enhanced cytotoxicity, especially when engineered with CAR constructs. However, due to variability observed between different PSC origins, our study emphasizes the importance of screening PSC lines to optimize NK cell differentiation and function prior to clinical application in immunotherapy.
Funding Source: This research was supported by a grant of Korean Cell-Based Artificial Blood Project funded by the Korean government (grant number: RS-2023-KH140925).
