Adoptive transfer of genetically modified Wilms' tumor 1-specific T cells in a novel malignant skull base meningioma model.

Background: Meningiomas are the most commonly diagnosed primary intracranial neoplasms. Despite significant advances in modern therapies, the management of malignant meningioma and skull base meningioma remains a challenge. Thus, the development of new treatment modalities is urgently needed for these difficult-to-treat meningiomas. The goal of this study was to investigate the potential of build-in short interfering RNA-based Wilms' tumor protein (WT1)-targeted adoptive immunotherapy in a reproducible mouse model of malignant skull base meningioma that we recently established.

Methods: We compared WT1 mRNA expression in human meningioma tissues and gliomas by quantitative real-time reverse-transcription polymerase chain reaction. Human malignant meningioma cells (IOMM-Lee cells) were labeled with green fluorescent protein (GFP) and implanted at the skull base of immunodeficient mice by using the postglenoid foramen injection (PGFi) technique. The animals were sacrificed at specific time points for analysis of tumor formation. Two groups of animals received adoptive immunotherapy with control peripheral blood mononuclear cells (PBMCs) or WT1-targeted PBMCs.

Results: High levels of WT1 mRNA expression were observed in many meningioma tissues and all meningioma cell lines. IOMM-Lee-GFP cells were successfully implanted using the PGFi technique, and malignant skull base meningiomas were induced in all mice. The systemically delivered WT1-targeted PBMCs infiltrated skull base meningiomas and significantly delayed tumor growth and increased survival time.

Conclusions: We have established a reproducible mouse model of malignant skull base meningioma. WT1-targeted adoptive immunotherapy appears to be a promising approach for the treatment of difficult-to-treat meningiomas.