CNSC-03. Angubindin-1-Mediated Disruption of Brain Endothelium Enhances T-cell Recruitment and Drug Delivery in Rodent Glioma Models

The blood-brain barrier (BBB) limits drug entry, allowing malignant glioma progression. Previous studies indicate that inhibition of tricellular junction protein angulin-1 (lipolysis-stimulated lipoprotein receptor/LSR) enhances brain delivery in non-tumor bearing rodents. Our studies evaluate the effect of LSR inhibition, with binding protein angubindin-1, on immune cell regulation and glioma progression. We first treated rat brain endothelial (RBMVEC), human-derived glioma (CBTN7316-6349 and LN229) and rat glioma cells (S635) with angubindin-1 (75-600 µg/mL) to assess LSR interaction via co-immunoprecipitation, cellular fractionation and immunoblotting over 24 hours. Immunocompetent and immunodeficient rats were intracranially injected with glioma cells then administered doxil (3 mg/kg), angubindin-1 (10 mg/kg), or combination therapy for 14 days and then monitored for toxicity/survival. We found that angubindin-1 dose-dependently increased LSR expression in endothelial and glioma cells, with statistical significance at 24 hours (p < 0.05). Cellular fractionation confirmed angubindin-1 binding to membrane LSR, with time-dependent decrease between 2-8 hours (p < 0.05). In the immunocompetent S635 rat glioma models, angubindin-1 increased CD3+ T-cell recruitment in tumoral and peritumoral (± 250 µm from tumor bulk) regions compared to control, doxil, and combination treatments (166 vs 235 cells/µm2, p < 0.01) and that CD4+ T-cell recruitment in peritumoral region was higher in all treatment groups compared to control (134 vs 149 vs 185 cells/µm2, p < 0.05). Interestingly, angubindin-1 and combination treatment reduced CD8+ T-cell recruitment in the peritumoral region (p < 0.01). No survival benefit was observed in immunodeficient S635 rat glioma models, suggesting increased CNS drug delivery must be paired with T-cell recruitment for favorable glioma effect from LSR inhibition. Ongoing studies explore angubindin-1’s role on human derived glioma cells/rodent models, with a focus on immune cell migration, drug delivery, and toxicity/survival. Collectively, these studies explore the role of angubindin-1 as a potential additive agent for BBB disruption for improved CNS treatment exposure, enhanced T-cell recruitment and prolonged survival.