The blood-brain barrier (BBB) defines the physiological function of the brain. Its disruption is common in multiple neuropathological diseases. Accumulating evidence suggest that BBB alterations occur in early stages of neurodegenerative diseases, being associated with neuronal loss processes. The vascular abnormalities and BBB leakage characterize the progression of gliomas, however it is unclear their correlation with the neurodegeneration observed in such tumors.
Methods: To establish the different gene signatures we have performed an in-silico analysis using glioma data sets and we have validated the results in a cohort of 26 gliomas (high and low grade) and 7 controls from non-tumor donors. We have also used patient-derived xenografts (PDXs) to correlate the degree of BBB disruption (measured by IgG extravasation immunofluorescence staining) with the neuronal loss (evaluated by NeuN immunofluorescence staining) and with the motor impairment (assessed by a rotarod test). Results: We measured the expression of a series of signatures associated with different biological processes, relevant for glioma development. The “Synapse” and the “BBB dysfunction” signatures were inversely correlated during glioma development. Thus, the most aggressive tumors were associated with BBB breakdown and neuronal dysfunction. These phenotypes correlate with the mesenchymal subtype of gliomas and with a shorter survival. The vascular normalization induced by the isocitrate dehydrogenase 1 (IDH1) mutations rescued the neuronal loss, reducing the motor impairment and increasing the overall survival of PDX-bearing mice. Conclusions: Our data demonstrate that vascular normalization can revert the neuronal loss and the aggressiveness in those tumors, which is linked to the appearance of motor dysfunction symptoms. Overall, we propose that disruption of the BBB is associated with neurodegeneration in glioma patients. These results could help us to understand the progression of this pathology as well as other neurodegenerative diseases and therefore to improve their therapeutic approaches.
Citation Format: Pablo Mata-Martínez, Berta Segura-Collar, Maria Garranzo-Asensio, Juan M. Sepúlveda-Sánchez, Aurelio Hernández-Lain, Pilar Sánchez-Gómez, Ricardo Gargini. Blood-brain barrier dysfunction leads to neuronal loss in glioma pathology [abstract]. In: Proceedings of the AACR Virtual Special Conference on the Evolving Tumor Microenvironment in Cancer Progression: Mechanisms and Emerging Therapeutic Opportunities; in association with the Tumor Microenvironment (TME) Working Group; 2021 Jan 11-12. Philadelphia (PA): AACR; Cancer Res 2021;81(5 Suppl):Abstract nr PO013.