Mesothelin is a surface antigen present on human meningioma and can be effectively targeted by CAR T-cells.

Abstract

Background: Meningioma is the most common primary CNS tumor, with high-grade cases exhibiting aggressive behavior, frequent recurrence, and poor prognosis. Currently, no systemic therapies are approved for recurrent or malignant meningiomas. Chimeric antigen receptor (CAR) T-cell therapy has shown efficacy in hematologic malignancies and promise for solid tumors but its use for meningiomas has been underexplored. Mesothelin, a glycoprotein overexpressed in several solid tumors of mesodermal origin, may serve as a viable immunotherapeutic target. This study aimed to evaluate mesothelin as a CAR T-cell target in meningiomas.

Methods: Mesothelin expression was analyzed in patient-derived meningioma samples using immunohistochemistry, flow cytometry, and droplet digital PCR. Mesothelin-specific CAR T-cells were generated and evaluated in vitro, ex vivo using patient-derived organotypic tumor spheroids (PDOTS), and in vivo using orthotopic meningioma mouse models of human xenografts. Cytotoxicity, T-cell proliferation, cytokine secretion, and tumor clearance were assessed.

Results: Mesothelin was detected in a subset of tumors across all meningioma grades at the transcript and protein levels, with surface expression confirmed in patient-derived primary cells. Mesothelin-specific CAR T-cells exhibited potent and specific cytotoxicity, T-cell activation, and cytokine secretion in vitro and effectively eliminated PDOTS. In orthotopic human xenograft models, mesothelin CAR T-cell therapy led to significant tumor regression and prolonged survival.

Conclusions: Mesothelin is a viable CAR T-cell target for meningiomas, and mesothelin-specific CAR T-cell therapy shows strong preclinical efficacy. These findings provide a rationale for early-phase clinical trials of mesothelin CAR T-cell therapy in patients with refractory meningiomas.