Impact of Glioblastoma Multiforme on Blood-Brain Barrier Integrity
Author
Sathiyalingam, Elaxmi
Term
4. term
Publication year
2024
Pages
61
Abstract
Glioblastoma multiforme (GBM) is an aggressive brain tumor; its presence disrupts the blood-brain barrier (BBB), creating a blood-brain tumor barrier (BBTB) that hinders drug delivery through loss of tight junctions, aberrant angiogenesis, and upregulated efflux transporters. This thesis examined how two GBM-associated cell lines, T10 and U87, influence BBB integrity. In vitro barrier models based on porcine brain capillary endothelial cells were established as monoculture and as co-cultures with either T10 or U87. Barrier function was assessed by trans-endothelial electrical resistance (TEER). Gene expression in the barrier models was profiled by RT-qPCR for claudin-5, ZO-1, transferrin receptor (TfR), VEGFR1, P-glycoprotein (P-gp), and LRP1, and the cancer cell lines were analyzed for EGFR, VEGF-A, COX-2, and Ang-2. Claudin-5 localization was visualized by immunocytochemistry, and a T10 xenograft mouse model was used for immunohistochemistry of claudin-5, VEGFR1, and P-gp. Co-culture with T10 yielded significantly higher TEER than endothelial monoculture, whereas co-culture with U87 showed significant decreases at selected time points. The barrier models displayed significant differences across setups in claudin-5, VEGFR1, P-gp, and LRP1 expression, and T10 expressed lower EGFR, VEGF-A, and COX-2 than U87. Staining confirmed the presence of claudin-5, VEGFR1, and P-gp. Together, the findings indicate that GBM cell heterogeneity leads to divergent effects on BBB properties, underscoring the need for further study to inform strategies for drug delivery in GBM.
Glioblastoma multiforme (GBM) er en aggressiv hjernetumor; tilstedeværelsen af tumor forstyrrer blod-hjerne-barrieren (BBB) og danner en blod-hjerne-tumor-barriere (BBTB), som besværliggør lægemiddeltransport gennem tab af stramme forbindelser, øget angiogenese og opregulering af effluks-transportører. Dette speciale undersøgte, hvordan to GBM-associerede cellelinjer, T10 og U87, påvirker BBB’s integritet. In vitro-barriemodeller med endothelceller fra svinehjernekapillærer blev etableret som monokultur og som samkulturer med enten T10 eller U87. Barrierefunktionen blev vurderet ved trans-endotelial elektrisk modstand (TEER). Genekspression i barriemodellerne blev analyseret med RT-qPCR for claudin-5, ZO-1, transferrinreceptor (TfR), VEGFR1, P-glykoprotein (P-gp) og LRP1, og kræftcellelinjerne blev undersøgt for EGFR, VEGF-A, COX-2 og Ang-2. Claudin-5-lokalisering blev visualiseret med immunocytokemi, og en T10-xenograft-musmodel blev anvendt til immunhistokemi af claudin-5, VEGFR1 og P-gp. Samkultur med T10 gav signifikant højere TEER end endothel-monokultur, mens samkultur med U87 viste signifikante fald på udvalgte tidspunkter. Barriemodellerne viste signifikante forskelle mellem opsætninger i ekspressionen af claudin-5, VEGFR1, P-gp og LRP1, og T10 udtrykte lavere EGFR, VEGF-A og COX-2 end U87. Farvninger bekræftede tilstedeværelsen af claudin-5, VEGFR1 og P-gp. Samlet peger resultaterne på, at heterogenitet mellem GBM-celler giver forskellige effekter på BBB-egenskaber, hvilket understreger behovet for yderligere studier til at informere strategier for lægemiddellevering ved GBM.
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