Angiopoietins in angiogenesis.

Abstract

Tie-1 and Tie-2 tyrosine kinase receptors are expressed specifically on vascular endothelial cells and on a certain subtype of macrophages implicated in angiogenesis, thus, they have been a major focus of angiogenesis research. Tie-1 and Tie-2 are essential for vascular maturation during developmental, physiological and pathological angiogenesis. Angiopoietin 1-4 (Ang-1-4) have been identified as bona fide ligands of the Tie-2 receptor, while Tie-1 remains an orphan receptor which is able to heterodimerize with Tie-2 and to modulate Tie-2 signal transduction. The most exhaustively studied angiopoietins are Ang-1 and Ang-2. Ang-1 is a critical player in vessel maturation and it mediates migration, adhesion and survival of endothelial cells. Ang-2 disrupts the connections between the endothelium and perivascular cells and promotes cell death and vascular regression. Yet, in conjunction with VEGF, Ang-2 promotes neo-vascularization. Hence, angiopoietins exert crucial roles in the angiogenic switch during tumor progression, and increased expression of Ang-2 relative to Ang-1 in tumors correlates with poor prognosis. Its central role in the regulation of physiological and pathological angiogenesis makes the angiopoietin/Tie signaling pathway a therapeutically attractive target for the treatment of vascular disease and cancer.

• Authors: Ernesta Fagiani, Gerhard Christofori
• Journal: Cancer letters (Cancer Lett) Vol. 328 Issue 1 Pg. 18-26 (Jan 01 2013) ISSN: 1872-7980 [Electronic] Ireland
• PMID: 22922303 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't, Review)
• Copyright: Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Chemical References

• Angiopoietins
• Receptor, TIE-1
• Receptor, TIE-2

Topics

• Angiopoietins (metabolism)
• Humans
• Neoplasms (blood supply)
• Neovascularization, Pathologic
• Receptor, TIE-1 (metabolism)
• Receptor, TIE-2 (metabolism)
• Signal Transduction (physiology)