Does VEGF facilitate local tumor growth and spread into the abdominal cavity by suppressing endothelial cell adhesion, thus increasing vascular peritoneal permeability followed by ascites production in ovarian cancer?

Background: Ovarian cancer is mostly associated with pathologically regulated permeability of peritoneal vessels, leading to ascites. Here, we investigated the molecular regulation of endothelial permeability by the vasc
Background: Ovarian cancer is mostly associated with pathologically regulated permeability of peritoneal vessels, leading to ascites. Here, we investigated the molecular regulation of endothelial permeability by the vascular endothelial growth factor (VEGF) and both tight and adherens junction proteins (VE-cadherin and claudin 5) with regards to the tumor biology of different ovarian cancer types.
Methods: Serum and ascites samples before and after surgery, as well as peritoneal biopsies of 68 ovarian cancer patients and 20 healthy controls were collected. In serum and ascites VEGF protein was measured by ELISA. In peritoneal biopsies co-localization of VE-cadherin and claudin 5 was investigated using immunohistochemical dual staining. In addition, the gene expression of VE-cadherin and claudin 5 was quantified by Real-time PCR. Differences in VEGF levels, VE-cadherin and claudin 5 gene expression were analyzed in relation to various tumor characteristics (tumor stage, grading, histological subtypes, resection status after surgery) and then compared to controls. Furthermore, human primary ovarian cancer cells were co-cultured with human umbilical vein endothelial cells (HUVEC) and changes in VE-cadherin and claudin 5 were investigated after VEGF inhibition.
Results: VEGF was significantly increased in tumor patients in comparison to controls and accumulates in ascites. The highest VEGF levels were found in patients diagnosed with advanced tumor stages, with tumors of poor differentiation, or in the group of solid / cystic-solid tumors. Patients with residual tumor after operation showed significantly higher levels of VEGF both before and after surgery as compared to tumor-free resected patients. Results of an immunohistochemical double-staining experiment indicated co-localization of VE-cadherin and claudin 5 in the peritoneal vasculature. Compared to controls, expression of VE-cadherin and claudin 5 was significantly suppressed in peritoneal vessels of tumor patients, but there were no significant differences regarding VE-cadherin and claudin 5 expression in relation to different tumor characteristics. A significant positive correlation was found between VE-cadherin and claudin 5 expression. VEGF inhibition in vitro was associated with significant increase in VE-cadherin and claudin 5.
Conclusions: Our results indicate that increased peritoneal permeability in ovarian cancer is due to down-regulation of adhesion proteins via tumor derived VEGF. Advanced ovarian cancer with aggressive tumor biology may be associated with early dysregulation of vascular permeability leading to ascites. These patients may benefit from therapeutic VEGF inhibition.
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Author:Inga Bekes, Thomas W. P. Friedl, Tanja Köhler, Volker Möbus, Wolfgang Janni, Achim Wöckel, Christine Wulf
Pubmed Id:
Parent Title (English):Molecular Cancer
Publisher:BioMed Central
Place of publication:London
Document Type:Article
Date of Publication (online):2016/02/12
Date of first Publication:2016/02/12
Publishing Institution:Universitätsbibliothek Johann Christian Senckenberg
Release Date:2016/10/17
Tag:Ascites; Claudin 5; Ovarian cancer; VE-cadherin; VEGF; Vascular permeability
First Page:1
Last Page:13
This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (, which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver ( applies to the data made available in this article, unless otherwise stated.
HeBIS PPN:428652522
Dewey Decimal Classification:610 Medizin und Gesundheit
Licence (German):License LogoCreative Commons - Namensnennung 4.0

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