The Korean Association for Immune Cell Engineering and Therapy (KAICET) 2026
IL-15-Stimulated hiPSC-Derived NK Cells Target TMZ-Surviving High-Grade Glioma Cells

Thi-Anh-Thuy Tran1, Young-Hee Kim1, Jung Eun Lee3, Sue-Jee Park2, Yeong Jin Kim2, Kyung-Sub Moon1, 2, In-Young Kim2, Shin Jung1, 2, Duck Cho4, Seung-Ho Yang3, Tae-Young Jung1, 2 *
1 Brain Tumor Research Laboratory, Chonnam National University Medical School and Hwasun Hospital, Hwasun, Republic of Korea.
2Department of Neurosurgery, Chonnam National University Medical School and Hwasun Hospital, Hwasun, Republic of Korea.
3 Department of Neurosurgery, College of Medicine, Seoul St. Mary’s Hospital, The Catholic University of Korea, Seoul, Republic of Korea.
4 Department of Laboratory Medicine and Genetics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.

Background
Temozolomide (TMZ) is the standard chemotherapy for high-grade glioma (HGG); however, TMZ-surviving tumor cells frequently contribute to recurrence and treatment resistance. Human induced pluripotent stem cell (hiPSC)-derived natural killer (NK) cells represent a scalable and renewable off-the-shelf immunotherapy platform. This study evaluated the therapeutic potential of IL-15-stimulated hiPSC-derived NK cells against TMZ-surviving HGG cells.
Methods
hiPSC-derived NK cells were differentiated from a hiPSC cell line and expanded using K562-OX40L-mbIL18/IL21 feeder cells. NK-cell phenotype and transcriptomic profiles were characterized and compared with peripheral blood-derived NK cells (PB-NK) by flow cytometry and RNA sequencing. Antitumor activity was evaluated in HGG cell lines with differential TMZ sensitivity, post-TMZ recurrent patient-derived GBM tumors, and primary GBM tumors with distinct MGMT methylation status. HGG cells were exposed to TMZ and subsequently co-cultured with hiPSC-NK cells with or without IL-15. Antitumor activity was assessed in 2D and 3D spheroid models by measuring tumor cell viability and IFN-γ production.
Results
Expanded hiPSC-derived NK cells exhibited mature NK-cell phenotypes and retained key NK-cell transcriptional signatures comparable to peripheral blood-derived NK cells. hiPSC-derived NK cells effectively eliminated TMZ-surviving tumor cells derived from both TMZ-resistant and TMZ-sensitive HGG cell lines. Robust antitumor activity was also observed against recurrent GBM cells obtained following standard TMZ treatment, either alone or after TMZ re-treatment. Similarly, hiPSC-derived NK cells effectively targeted TMZ-surviving primary GBM cells derived from newly diagnosed patients regardless of MGMT methylation status. Tumor killing was accompanied by increased IFN-γ secretion and NK-cell degranulation. In 3D spheroid cultures, hiPSC-derived NK cells significantly reduced spheroid growth and increased tumor cell death. Notably, their anti-tumor activity was comparable to PB-NK cells and superior to NK-92 cells. Furthermore, IL-15 stimulation consistently enhanced hiPSC-derived NK-cell cytotoxicity and IFN-γ production across multiple HGG models.
Conclusion
hiPSC-derived NK cells effectively targeted TMZ-surviving and recurrent HGG cells across multiple preclinical models. IL-15 stimulation further enhanced NK-cell cytotoxicity and IFN-γ production. Collectively, these findings support IL-15-enhanced hiPSC-derived NK cells as a promising off-the-shelf immunotherapeutic strategy for high-grade glioma.

Acknowledgement: This work was supported by a National Research Foundation (NRF) grant of Korea funded by the Ministry of Science & ICT (RS-2024-00353589).