Elevated expression of endoglin, a component of the TGF-β-receptor complex, correlates with proliferation of tumor endothelial cells

✍ Scribed by Daniel W. Miller; Wolff Graulich; Bernadett Karges; Sabine Stahl; Michael Ernst; Annette Ramaswamy; H.-Harald Sedlacek; Rolf Müller; Jürgen Adamkiewicz

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: French
• Weight: 161 KB
• Volume: 81
• Category: Article
• ISSN: 0020-7136
• DOI: 10.1002/(sici)1097-0215(19990517)81:4<568::aid-ijc11>3.0.co;2-x

✦ Synopsis

Endoglin/CD105 is a membrane protein involved in the TGF-␤ receptor signalling pathway. Endoglin expression has been reported to be selective for a few cell types, in particular endothelial cells, although a number of conflicting reports have been published. In this study, we performed a detailed analysis of endoglin expression in human lung tumors and different tumor and endothelial cell lines, employing reversetranscriptase-polymerase-chain reaction as well as immunoblotting and immunohistochemistry using verified antibodies to endoglin. Our data show a clearly preferential expression of both endoglin mRNA and protein in endothelial cells. In tumors, endoglin expression was strongly elevated in the angiogenic endothelium at the tumor edges. In agreement with this observation, we find a clear correlation between endoglin expression and markers of proliferation, such as cyclin A and Ki-67, suggesting that endoglin expression is linked to cell-cycle regulation. These findings not only resolve some of the discrepancies in the literature, but also provide the basis for further applications making use of its selective localization and expression in the tumor vasculature.