IL15 modification enables CAR T cells to act as a dual targeting agent against tumor cells and myeloid-derived suppressor cells in GBM

Autor: Stephen Gottschalk, Maciej S Lesniak, Irina V Balyasnikova, Jason Miska, Catalina Lee-Chang, Markella Zannikou, Joseph T Duffy, Rebecca N Levine, Maggie Seblani, Qianli Liu, Aaron Presser, Victor A Arrieta, Christopher J Chen, Adam M Sonabend, Craig M Horbinski
Jazyk: angličtina
Rok vydání: 2023
Předmět:
Zdroj: Journal for ImmunoTherapy of Cancer, Vol 11, Iss 2 (2023)
Druh dokumentu: article
ISSN: 2051-1426
DOI: 10.1136/jitc-2022-006239
Popis: Introduction The immunosuppressive tumor microenvironment (TME) is a major barrier to the efficacy of chimeric antigen receptor T cells (CAR-T cells) in glioblastoma (GBM). Transgenic expression of IL15 is one attractive strategy to modulate the TME. However, at present, it is unclear if IL15 could be used to directly target myeloid-derived suppressor cells (MDSCs), a major cellular component of the GBM TME. Here, we explored if MDSC express IL15Rα and the feasibility of exploiting its expression as an immunotherapeutic target.Methods RNA-seq, RT-qPCR, and flow cytometry were used to determine IL15Rα expression in paired peripheral and tumor-infiltrating immune cells of GBM patients and two syngeneic murine GBM models. We generated murine T cells expressing IL13Rα2-CARs and secretory IL15 (CAR.IL15s) or IL13Rα2-CARs in which IL15 was fused to the CAR to serve as an IL15Rα-targeting moiety (CAR.IL15f), and characterized their effector function in vitro and in syngeneic IL13Rα2+glioma models.Results IL15Rα was preferentially expressed in myeloid, B, and dendritic cells in patients’ and syngeneic GBMs. In vitro, CAR.IL15s and CAR.IL15f T cells depleted MDSC and decreased their secretion of immunosuppressive molecules with CAR.IL15f T cells being more efficacious. Similarly, CAR.IL15f T cells significantly improved the survival of mice in two GBM models. TME analysis showed that treatment with CAR.IL15f T cells resulted in higher frequencies of CD8+T cells, NK, and B cells, but a decrease in CD11b+cells in tumors compared with therapy with CAR T cells.Conclusions We demonstrate that MDSC of the glioma TME express IL15Ra and that these cells can be targeted with secretory IL15 or an IL15Rα-targeting moiety incorporated into the CAR. Thus, IL15-modified CAR T cells act as a dual targeting agent against tumor cells and MDSC in GBM, warranting their future evaluation in early-phase clinical studies.
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