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Angiogenic switch and vascular stability in human Leydig cell tumours
1Department of Anatomy, University Hospital Eppendorf, Hamburg, Germany.
Angiogenesis
|October 1, 2003
Summary
Leydig cell tumors exhibit altered vascular endothelial growth factor (VEGF) signaling, with VEGF-KDR interactions potentially destabilizing tumor blood vessels. Stabilized vessels in tumors may explain their low malignancy.
Area of Science:
- Oncology
- Vascular Biology
- Endocrinology
Background:
- Human Leydig cell tumors show high vascularization and low malignancy.
- Studying tumor neovascularization and vascular wall stabilization is crucial.
Purpose of the Study:
- To investigate the role of vascular endothelial growth factor (VEGF) and its receptors in Leydig cell tumors.
- To understand the mechanisms behind vascular destabilization and stabilization in these tumors.
Main Methods:
- Analysis of VEGF, VEGF mRNA, and its receptors (KDR, Flt-1) in tumor and normal tissues.
- Ultrastructural examination of vascular walls in tumor marginal, peri-tumoral, and central regions.
- In vitro application of VEGF(165) to normal testicular tissue.
Main Results:
- Leydig cell tumors have increased VEGF in testicular veins and express VEGF mRNA and KDR, but lack Flt-1 in peri-tumoral vessels.
- Normal Leydig cell capillaries express both Flt-1 and KDR.
- Vascular destabilization (lack of basement membrane/peri-endothelial cells) was observed in peri-tumoral areas, while tumor center vessels were stabilized.
- VEGF(165) application induced destabilization in KDR-expressing normal capillaries.
Conclusions:
- VEGF may act in an autocrine manner on tumor endothelial cells, with VEGF-KDR interaction (without Flt-1) potentially causing vascular destabilization.
- Stabilized vascular walls in 79% of Leydig tumor vessels may contribute to their low malignant potential.