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

Sonia Kiran; Yu Xue; Drishty B Sarker; Yan Li; Qing-Xiang Amy Sang

doi:10.1016/j.bioactmat.2024.02.031

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

Bioact Mater. 2024 Mar 8:36:301-316. doi: 10.1016/j.bioactmat.2024.02.031. eCollection 2024 Jun.

Authors

Sonia Kiran¹, Yu Xue¹, Drishty B Sarker¹, Yan Li^{2

3}, Qing-Xiang Amy Sang^{1

3}

Affiliations

¹ Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL 32306-4390, USA.
² Department of Chemical and Biomedical Engineering, FAMU-FSU College of Engineering, Florida State University, Tallahassee, FL, 32310-6046, USA.
³ Institute of Molecular Biophysics, Florida State University, Tallahassee, FL, 32306-4380, USA.

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 in vitro 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^bright CD16^bright 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^bright CD16^bright 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^-ve CD16^bright 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 in vitro, offer valuable insights into potential immunotherapeutic strategies for brain tumors.

Keywords: Atypical teratoid rhabdoid tumor; Cytokine activation; Cytotoxicity; Human induced pluripotent stem cells; Natural killer cells.