Vascular endothelial growth factor receptor 2 (VEGFR-2) signalling activity in paediatric pilocytic astrocytoma is restricted to tumour endothelial cells
| Autor: | A H, Sikkema, E S J M, de Bont, G, Molema, A, Dimberg, P J, Zwiers, S H, Diks, E W, Hoving, W A, Kamps, M P, Peppelenbosch, W F A, den Dunnen |
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| Rok vydání: | 2011 |
| Předmět: |
Vascular Endothelial Growth Factor Receptor-1
Neovascularization Pathologic Reverse Transcriptase Polymerase Chain Reaction Lasers Protein Array Analysis Endothelial Cells Fluorescent Antibody Technique Astrocytoma Vascular Endothelial Growth Factor Receptor-3 Vascular Endothelial Growth Factor Receptor-2 Humans RNA Messenger Phosphorylation Child Microdissection Signal Transduction |
| Zdroj: | Neuropathology and applied neurobiology. 37(5) |
| ISSN: | 1365-2990 |
| Popis: | Tumours depend on angiogenesis for enhanced tumour cell survival and progression. Vascular endothelial growth factor receptor (VEGFR) signalling plays a major part in this process. Previously, we evaluated tyrosine kinase activity in paediatric brain tumour tissue lysates using a peptide microarray containing 144 different tyrosine kinase peptide substrates. When applied to paediatric pilocytic astrocytoma tissue, this analysis revealed extensive phosphorylation of VEGFR-derived peptides. The aim of the current study was to validate this result and determine the presence of VEGFR-2 activity in paediatric pilocytic astrocytoma as the main VEGFR in terms of mitogenic signalling. In addition, the localization of VEGFR1-3 mRNA expression was assessed.VEGFR-2 phosphorylation was determined by adopting a proximity ligation assay approach. Enrichment of endothelial markers and VEGFRs in tumour endothelium was determined by quantitative polymerase chain reaction (qPCR) analysis of laser-microdissected blood vessels.Proximity ligation assays on tumour cryosections showed the presence of phosphorylation of VEGFR-2, which primarily localized to vascular endothelium. qPCR analysis of endothelial markers and VEGFRs showed a 13.6-fold average enrichment of VEGFR-2 expression in the laser-microdissected endothelium compared to whole tumour. Also the expression of VEGFR-1 and -3 was highly enriched in the endothelium fraction with an average fold-enrichment of 16.5 and 50.8 respectively.Phosphorylated VEGFR-2 is detected on endothelial cells in paediatric pilocytic astrocytoma. Furthermore, endothelial cells are the main source of VEGFR1-3 mRNA expression. This suggests a crucial role for VEGF/VEGFR-induced angiogenesis in the progression and maintenance of these tumours. |
| Databáze: | OpenAIRE |
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