Novel EGFRvIII-CAR transgenic mice for rigorous preclinical studies in syngeneic mice.

Neuro-oncology 2022 Feb 01

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Rigorous preclinical studies of chimeric antigen receptor (CAR) immunotherapy will require large quantities of consistent and high-quality CAR-transduced T (CART) cells that can be used in syngeneic mouse glioblastoma (GBM) models. To this end, we developed a novel transgenic (Tg) mouse strain with a fully murinized CAR targeting epidermal growth factor receptor variant III (EGFRvIII). We first established the murinized version of EGFRvIII-CAR and validated its function using a retroviral vector (RV) in C57BL/6J mice bearing syngeneic SB28 GBM expressing EGFRvIII. Next, we created C57BL/6J-background Tg mice carrying the anti-EGFRvIII-CAR downstream of a Lox-Stop-Lox cassette in the Rosa26 locus. We bred these mice with CD4-Cre Tg mice to allow CAR expression on T cells and evaluated the function of the CART cells both in vitro and in vivo. To inhibit immunosuppressive myeloid cells within SB28 GBM, we also evaluated a combination approach of CART and an anti-EP4 compound (ONO-AE3-208). Both RV- and Tg-CART cells demonstrated specific cytotoxic activities against SB28-EGFRvIII cells. A single intravenous infusion of EGFRvIII-CART cells prolonged the survival of glioma-bearing mice when preceded by a lymphodepletion regimen with recurrent tumors displaying profound EGFRvIII loss. The addition of ONO-AE3-208 resulted in long-term survival in a fraction of CART-treated mice and those survivors demonstrated delayed growth of subcutaneously re-challenged both EGFRvIII+ and parental EGFRvIII- SB28. Our new syngeneic CAR Tg mouse model can serve as a useful tool to address clinically relevant questions and develop future immunotherapeutic strategies. © The Author(s) 2021. Published by Oxford University Press on behalf of the Society for Neuro-Oncology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Citation

Pavlina Chuntova, Yafei Hou, Ryosuke Naka, Akane Yamamichi, Tiffany Chen, Yitzhar Goretsky, Ryusuke Hatae, Takahide Nejo, Gary Kohanbash, Abigail L Mende, Megan Montoya, Kira M Downey, David Diebold, Jayne Skinner, Hong-Erh Liang, Bjoern Schwer, Hideho Okada. Novel EGFRvIII-CAR transgenic mice for rigorous preclinical studies in syngeneic mice. Neuro-oncology. 2022 Feb 01;24(2):259-272