EXTH-53 - VEGFR2-specific CAR-T cells show improved tumor infiltration in syngeneic mouse glioma models

Friday, November 17, 2023

7:30 PM – 9:30 PM PT

Location: Exhibit Hall A/B

Poster Presenter(s)

Maximilian Mastall

Department of Neurology and Clinical Neuroscience Center, University Hospital and University of Zurich, Zurich, Switzerland
Zurich, Switzerland

Author(s)

GD

Gina Dunkel

Department of Preclinical Imaging and Radiopharmacy, Eberhard Karls University of Tuebingen, Tuebingen, Germany
Tuebingen, Germany
Manuela Silginer

Department of Neurology and Clinical Neuroscience Center, University Hospital and University of Zurich, Zurich, Switzerland
Zurich, Zurich, Switzerland
NO

Naoki Okada

Laboratory of Vaccine and Immune Regulation (BIKEN), Graduate School of Pharmaceutical Sciences, Osaka University, Osaka, Japan
Osaka, Japan
Tobias Weiss

Department of Neurology and Clinical Neuroscience Center, University Hospital and University of Zurich, Zurich, Switzerland
Zurich, Switzerland
Michael Weller

Department of Neurology and Clinical Neuroscience Center, University Hospital and University of Zurich, Zurich, Switzerland
Zurich, Zurich, Switzerland
BW

Bettina Weigelin

Department of Preclinical Imaging and Radiopharmacy, Eberhard Karls University of Tuebingen, Tuebingen, Germany
Tuebingen, Germany
Patrick Roth

Department of Neurology, University Hospital and University of Zurich, Zurich, Switzerland
Zurich, Zurich, Switzerland

Background: Chimeric antigen receptor (CAR-)T cell therapy, a powerful immunotherapy against hematological malignancies, has so far limited efficiency in solid tumors. Also in glioblastoma, a major obstacle remains limited infiltration of CAR-T cells into the tumor. Vessel-targeting CAR-T cells have been shown to infiltrate solid tumors more efficiently. Vascular endothelial growth factor receptor 2 (VEGFR2) is expressed in the glioma vasculature and VEGFR2-specific CAR-T cells prolong the survival of xenograft glioma-bearing mice. In this study, we investigated the efficacy of murine VEGFR2-specific CAR-T cells against syngeneic experimental gliomas and assessed the CAR-T cell infiltration of this approach.

Methods: VEGFR2-CAR-T cells were generated by retroviral transduction to express a second generation CAR construct. Their activity was assessed in co-culture assays in vitro against murine endothelial and glioma cells, respectively. Syngeneic orthotopic mouse glioma models were used to explore the infiltration of intravenously administered CAR-T cells by in vivo fluorescence molecular tomography (FMT), ex vivo flow cytometry as well as ex vivo 3D light-sheet fluorescence microscopy (LSFM).

Results: VEGFR2-CAR-T cells showed anti-endothelial and anti-glioma activity in vitro. Intravenous treatment with fluorescently labeled CAR-T or mock-transduced T cells of tumor-bearing mice resulted in a higher FMT signal at the tumor site. This was confirmed by ex vivo flow cytometry, wherein CAR-T cells represented a larger fraction of all T cells within the tumor (26.5% CAR versus 5.4% Mock, p=0.0013) resulting in a higher donor T cell to tumor cell ratio. Similarly, significantly more VEGFR2-CAR-T cells were detected at the tumor site compared to tumor-targeting (but not vessel-targeting) control CAR-T cells. Currently, VEGFR2-CAR-T cell infiltration patterns as well as vasculature density are further investigated and visualized by LSFM.

Conclusion: VEGFR2-CAR-T cells show improved glioma infiltration in syngeneic mouse models. Therefore, VEGFR2 might be a relevant target that could improve CAR-T cell infiltration in glioblastoma.