Feeder-free differentiation of human iPSCs into natural killer cells with cytotoxic potential against malignant brain rhabdoid tumor cells.

Kiran, Sonia; Xue, Yu; Sarker, Drishty B; Li, Yan; Sang, Qing-Xiang Amy · Bioact Mater · 2024

basic_science · Level V

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Abstract

Natural killer (NK) cells are cytotoxic immune cells that can eliminate target cells without prior stimulation. Human induced pluripotent stem cells (iPSCs) provide a robust source of NK cells for safe and effective cell-based immunotherapy against aggressive cancers. In this <i>in vitro</i> study, a feeder-free iPSC differentiation was performed to obtain iPSC-NK cells, and distinct maturational stages of iPSC-NK were characterized. Mature cells of CD56<sup>bright</sup> CD16<sup>bright</sup> phenotype showed upregulation of CD56, CD16, and NK cell activation markers NKG2D and NKp46 upon IL-15 exposure, while exposure to aggressive atypical teratoid/rhabdoid tumor (ATRT) cell lines enhanced NKG2D and NKp46 expression. Malignant cell exposure also increased CD107a degranulation markers and stimulated IFN-γ secretion in activated NK cells. CD56<sup>bright</sup> CD16<sup>bright</sup> iPSC-NK cells showed a ratio-dependent killing of ATRT cells, and the percentage lysis of CHLA-05-ATRT was higher than that of CHLA-02-ATRT. The iPSC-NK cells were also cytotoxic against other brain, kidney, and lung cancer cell lines. Further NK maturation yielded CD56<sup>-ve</sup> CD16<sup>bright</sup> cells, which lacked activation markers even after exposure to interleukins or ATRT cells - indicating diminished cytotoxicity. Generation and characterization of different NK phenotypes from iPSCs, coupled with their promising anti-tumor activity against ATRT <i>in vitro</i>, offer valuable insights into potential immunotherapeutic strategies for brain tumors.