Background: Natural Killer (NK) cells are a type of immune cells that belong to the innate immune system and executes a rapid immune reaction against cancer cells and viruses without prior activation. The huge success of chimeric antigen receptor (CAR)-T cells has motivated scientists to genetically modify human NK cells with CARs to further improve their tumor killing capacity. To engineer NK cells with a CAR, NK cells can be isolated from peripheral blood and umbilical cord blood. NK cells can also be derived from induced pluripotent stem cells (iPSCs) to produce a homogenous and standardized group of NK cells for the treatment of cancer. Here, we test the feasibility to engineer our EGFR-CAR construct into iPSC-derived hematopoietic stem cells (iPSC-HSC) to generate EGFR-CAR NK cells that will eradicate glioblastoma (GBM).
Material and Methods: iPSCs-derived HSCs were differentiated into NK cells using co-culture with a feeder stroma of OP9-DL1 cells in the presence of human cytokines and NK cells were assessed by flow cytometry. Expanded NK cells (with K562 feeder cells expressing mb-IL-21 and 4-1BB) and HSCs from peripheral blood were efficiently transduced with a retroviral vector, carrying a CAR targeting EGFR. CAR expression was assessed by flow cytometry. After transduction, the CAR-NK cells were collected for cytotoxicity assay to test their efficacy. CAR-HSCs were differentiated into CAR-NK cells utilizing OP9-DL1 stroma cells.
Results: Our results demonstrated that iPSCs can be fully differentiated into NK cells expressing typical NK cell surface markers including CD56, NKp46, CD16 and NKG2A, etc. In addition, HSCs can be engineered with EGFR-CAR without affecting their differentiation into CAR-NK cells. Our engineered EGFR-CAR NK cells showed an enhanced antitumor activity against GBM compared to NK cells without the EGFR-CAR.
Conclusion: Collectively, our study suggests the feasibility of engineering CAR-EGFR NK cells from iPSCs for effective “off the shelf” immunotherapy. Our approach can be utilized to generate an unlimited number of CAR-NK cells to treat patients with cancer such as GBM in the clinical setting.
Citation Format: Melissa Yu, Anthony G. Mansour, Kun-Yu Teng, Guoqiang Sun, Yanhong Shi, Michael A. Caligiuri. iPSC-derived natural killer cells expressing EGFR-CAR against glioblastoma [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 3313.