B7-H3-targeted natural killer cells effectively kill atypical teratoid / rhabdoid tumors and extend survival in orthotopic xenografts

Choe, T.; Chakravarti, S.; Holl, N. J.; Zinsky, M. T.; Jones, D. G.; Guchhait, S.; Rahnama, R.; Vorri, S. C.; Amaral, A.; Lucas, C.-H. G.; Raabe, E. H.; Bonifant, C.

doi:10.64898/2026.01.15.699746

bioRxiv · 10.64898/2026.01.15.699746

B7-H3-targeted natural killer cells effectively kill atypical teratoid / rhabdoid tumors and extend survival in orthotopic xenografts

Choe, T.·Chakravarti, S.·Holl, N. J.·Zinsky, M. T.·Jones, D. G.·Guchhait, S.·Rahnama, R.·Vorri, S. C.·Amaral, A.·Lucas, C.-H. G.·Raabe, E. H.·Bonifant, C.

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Abstract

BackgroundAtypical teratoid/rhabdoid tumors (AT/RTs) are the most common malignant CNS tumor in infants, and patients suffer from low survival rates and treatment-related morbidities. These tumors frequently overexpress the pan-cancer antigen B7-H3 (CD276), which can be targeted with immunotherapy. We hypothesized that adding a B7-H3-targeting cytotoxic chimeric antigen receptor (CAR) to NK cells can enhance killing against AT/RTs. MethodsWe designed a library of variable affinity B7-H3-targeted CARs, which were transduced into primary healthy donor-derived NK cells. We verified B7-H3 expression in a panel of AT/RT cell lines and further engineered luciferase and nuclear GFP-expressing AT/RT (CHLA-04, CHLA-06, BT12, BT37) as well as a CHLA-06-derived B7-H3 knockout. We tested CAR-NK cell functionality using in vitro co-culture cytotoxicity assays. We delivered anti-B7-H3 CAR-NK cells intratumorally or intracerebroventricularly (ICV) to AT/RT orthotopic xenografts and monitored for tumor growth and animal survival. ResultsB7-H3-targeted CAR-NK cells demonstrated target-specific cytotoxicity when compared to unmodified NK cells. Knockout of B7-H3 in target cells abolished the increased CAR-mediated target killing. When delivered intratumorally to CHLA-06 orthotopic xenograft-bearing mice, anti-B7-H3 CAR-NK cells eliminated tumor cells and prolonged survival. When CAR-NK cells were delivered ICV against a CNS disseminated tumor model of BT12, treated mice had significantly improved survival. ConclusionsAnti-B7-H3 CAR-NK cells effectively kill AT/RTs in multiple pre-clinical in vitro and in vivo models in an antigen-specific manner. Evidence of efficacy in translationally relevant models provides support for using B7-H3-targeting CAR-NK cells in high-risk AT/RT patients.

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Choe, T., Chakravarti, S., Holl, N. J., Zinsky, M. T., Jones, D. G., Guchhait, S., Rahnama, R., Vorri, S. C., Amaral, A., Lucas, C.-H. G., Raabe, E. H., Bonifant, C.. 2026-01-16. B7-H3-targeted natural killer cells effectively kill atypical teratoid / rhabdoid tumors and extend survival in orthotopic xenografts. https://doi.org/10.64898/2026.01.15.699746

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