10246-CB-9 Preclinical Model Development for AAV-Mediated Gene Therapy in Brain Tumors

Abstract Background Driver mutations involved in brain tumorigenesis are being increasingly identified, and the expansion of cancer genome profiling has enabled their detection in clinical practice. However, actionable targets for molecular therapies remain limited. In hereditary neurological diseases, gene therapy using adeno-associated virus (AAV) vectors–known for their safety and stability–is already in clinical use to deliver functional copies of disease-causing genes. In contrast, its application to brain tumors remains underexplored, and the development of suitable preclinical models is urgently needed. Methods We evaluated the blood-brain barrier (BBB) permeability and tumor transduction efficiency of BBB-penetrating AAVs (PHP. eB and AAV-F) following intravenous or local delivery to orthotopic xenografts of human medulloblastoma and allografts derived from murine neural stem cells. Results Intravenous injection into nude mice revealed that PHP. eB failed to cross the BBB, while AAV-F did penetrate but showed low transduction efficiency in D425 xenografts. We then shifted to local injection and tested nine AAV serotypes in D425 tumors; AAV-DJ showed the highest efficiency but remained confined along the needle tract. For allograft evaluation, we established a murine brain tumor model using neural stem cells engineered with p53 and Atrx mutations plus Mycn amplification. Systemic delivery of PHP. eB in B6 mice demonstrated BBB permeability and moderate infection of tumor cells. Conclusion To develop gene replacement therapy for brain tumors, we attempted to establish a model that overcomes the challenges of BBB permeability and tumor cell capsid tropism. Although AAV vectors are non-replicative and may have limited compatibility with tumors, they hold promise for preventive treatment of hereditary brain tumors, delivery of tumoricidal secretory proteins with selective cytotoxicity, or targeting of non-dividing cells in the tumor microenvironment. These potential applications warrant further investigation.