P32-specific CAR T cells with dual antitumor and antiangiogenic therapeutic potential in gliomas

Liat Rousso-Noori,Shauli Talmor,Tova Waks,Luis Alvarez-Vallina,Anat Globerson Levin,Dinorah Friedmann-Morvinski,Zelig Eshhar,Tambet Teesalu,Ignacio Mastandrea,Maarja Haugas

doi:10.1038/s41467-021-23817-2

Abstract

Glioblastoma is considered one of the most aggressive malignancies in adult and pediatric patients. Despite decades of research no curative treatment is available and it thus remains associated with a very dismal prognosis. Although recent pre-clinical and clinical studies have demonstrated the feasibility of chimeric antigen receptors (CAR) T cell immunotherapeutic approach in glioblastoma, tumor heterogeneity and antigen loss remain among one of the most important challenges to be addressed. In this study, we identify p32/gC1qR/HABP/C1qBP to be specifically expressed on the surface of glioma cells, making it a suitable tumor associated antigen for redirected CAR T cell therapy. We generate p32 CAR T cells and find them to recognize and specifically eliminate p32 expressing glioma cells and tumor derived endothelial cells in vitro and to control tumor growth in orthotopic syngeneic and xenograft mouse models. Thus, p32 CAR T cells may serve as a therapeutic option for glioblastoma patients.

Highlights

Glioblastoma is considered one of the most aggressive malignancies in adult and pediatric patients
We identified p32/gC1qR/hyaluronic acid binding protein (HABP)/C1qBP to be the receptor for the CGKRK peptide, expressed in high levels on the surface of tumor cells and tumor-associated endothelial cells[13]
Among the known list of challenges is the identification of a suitable neoantigen or tumorassociated antigen (TAA) to re-direct the engineered chimeric antigen receptors (CAR) T cells

Summary

Results

P32 is expressed in murine and human glioma. Others and we have identified p32 as the receptor for three tumor-homing peptides targeted nanoparticles: Lyp-1, CGKRK, and LinTT113,20,21. p32 expression is significantly up-regulated in human cancers compared to their corresponding normal tissue[20], and it is primarily expressed in the mitochondria[17,22], several studies reported the expression of p32 on the surface of malignant cells[23,24]. Specific cytotoxic activity and CAR+ T cell expansion were further confirmed by co-culture of SP6 and p32 mCAR T cells with GFP+ glioma cells and analyzed by flow cytometry (Supplementary Fig. 5a). While p32 hCAR T cells were able to exert their cytotoxic effect (Fig. 3e and Supplementary Fig. 5b), proliferate (Fig. 3f) and secrete IFN-γ (Fig. 3g) when co-culture with glioma cells, UT T cells showed little to no response These results demonstrate that both murine and human p32 CAR T cells recognize p32+ glioma target cells and are able to kill only p32-expressing glioma cells. No toxic or adverse effects were observed in the mice infused with p32 mCAR T cells (Supplementary Fig. 6a), suggesting specificity and safety of these CAR T cells in vivo. Our results suggest that p32 CAR T cells are able to recognize tumor cells and tumor-associated endothelial cells, suggesting a possible antiangiogenic effect of p32 CAR T cells by targeting the tumor vasculature

Discussion

Findings

Methods