IL-4 IMMUNOTHERAPY TARGETING THE UNIQUE EXTRACELLULAR MATRIX IN RECURRENT GLIOBLASTOMA

Abstract Glioblastoma (GBM) is an aggressive primary brain tumor characterized by high treatment resistance and an extremely high rate of recurrence. To understand the mechanisms of treatment resistance and develop novel therapeutic approaches, we prepared 11 patient-derived human GBM cells and 5 mouse GBM cells from genetically engineered mouse models. We performed repeated irradiation for them to analyze the mechanisms of acquired resistance. During repeated irradiation, GBM cells enhanced radio- and chemo-resistance, increased invasiveness, and elevated ability to establish an immunosuppressive microenvironment. We identified upregulation of Collagen type I and III (COL I & III) as crucial for this adaptive resistance. COL I & III, rarely expressed in normal brain tissue but highly expressed in resistant GBM, emerged as potential markers for targeting therapy-resistant GBM tumors. To apply these findings to treatment, we focused on von Willebrand factor (vWF), which selectively binds to expose COL I & III in abnormal tissues. We developed CBD-IL-12 by conjugating vWF’s collagen-binding domain (CBD) into the immunostimulatory cytokine IL-12. In mouse models of therapy-resistant GBM, intravenously administered CBD-IL-12 accumulated specifically in tumor sites, without accumulating in normal brain tissue or other healthy organs. CBD-IL-12 enhanced dendritic cell recruitment, increased CD8+ T cell infiltration, and improved the immunosuppressive tumor environment, resulting in tumor suppression and significantly prolonged survival. Our findings suggest that extracellular matrix proteins have tumor-specific and abundant presence in the tumor microenvironment, indicating their potential application in targeted therapy. We demonstrated that therapy-resistant GBM cells exhibited upregulated expression of COL I & III, and CBD can be utilized to selectively deliver cytokines to tumor sites. This CBD-based immunotherapy approach shows promise in transforming the treatment landscape for recurrent GBM, offering a novel strategy to combat this challenging malignancy.