title: Thymidine phosphorylase and 2-deoxyribose stimulate human endothelial cell migration by specific activation of the integrins alpha 5 beta 1 and alpha V beta 3.
abstract: Thymidine phosphorylase is an angiogenic factor that is frequently overexpressed in solid tumors, in rheumatoid arthritis, and in response to inflammatory cytokines. Our previous studies showed that cells expressing thymidine phosphorylase stimulated endothelial cell migration in vitro. This was a consequence of the intracellular metabolism of thymidine by thymidine phosphorylase and subsequent extracellular release of 2-deoxyribose. The mechanisms by which 2-deoxyribose might mediate thymidine phosphorylase-induced cell migration in vitro, however, are obscure. Here we show that both thymidine phosphorylase and 2-deoxyribose stimulated the formation of focal adhesions and the tyrosine 397 phosphorylation of focal adhesion kinase in human umbilical vein endothelial cells. Although similar actions occurred upon treatment with the angiogenic factor vascular endothelial growth factor (VEGF), thymidine phosphorylase differed from VEGF in that its effect on endothelial cell migration was blocked by antibodies to either integrin alpha 5 beta 1 or alpha v beta 3, whereas VEGF-induced endothelial cell migration was only blocked by the alpha v beta 3 antibody. Further, thymidine phosphorylase and 2-deoxyribose, but not VEGF, increased the association of both focal adhesion kinase and the focal adhesion-associated protein vinculin with integrin alpha 5 beta 1 and, in intact cells, increased the co-localization of focal adhesion kinase with alpha 5 beta 1. Thymidine phosphorylase and 2-deoxyribose-induced focal adhesion kinase phosphorylation was blocked by the antibodies to alpha 5 beta 1 and alpha v beta 3, directly linking the migration and signaling components of thymidine phosphorylase and 2-deoxyribose action. Cell surface expression of alpha 5 beta 1 was also increased by thymidine phosphorylase and 2-deoxyribose. These experiments are the first to demonstrate a direct effect of thymidine phosphorylase and 2-deoxyribose on signaling pathways associated with endothelial cell migration.
authors.affiliation: Department of Oncology, Albert Einstein College of Medicine, Bronx, New York 10467, USA.
authors.forename: Kylie A
authors.initials: KA
authors.lastname: Hotchkiss
authors.forename: Anthony W
authors.initials: AW
authors.lastname: Ashton
authors.forename: Edward L
authors.initials: EL
authors.lastname: Schwartz
mesh_terms: D000906:Antibodies / Q000494:pharmacology; D002465:Cell Movement / Q000187:drug effects*; D003855:Deoxyribose / Q000494:pharmacology*; D016228:Endothelial Growth Factors / Q000494:pharmacology; D004730:Endothelium, Vascular / Q000166:cytology*; D051417:Focal Adhesion Kinase 1; D051416:Focal Adhesion Protein-Tyrosine Kinases; D006801:Humans; D039081:Integrin alpha5beta1 / Q000276:immunology / Q000502:physiology*; D039302:Integrin alphaVbeta3 / Q000276:immunology / Q000502:physiology*; D036341:Intercellular Signaling Peptides and Proteins / Q000494:pharmacology; D008222:Lymphokines / Q000494:pharmacology; D010766:Phosphorylation; D019000:Phosphotyrosine / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D013939:Thymidine Phosphorylase / Q000494:pharmacology*; D014471:Umbilical Veins; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; D016596:Vinculin / Q000378:metabolism
chemical_list: D000906:Antibodies; D016228:Endothelial Growth Factors; D039081:Integrin alpha5beta1; D039302:Integrin alphaVbeta3; D036341:Intercellular Signaling Peptides and Proteins; D008222:Lymphokines; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; D016596:Vinculin; D019000:Phosphotyrosine; D003855:Deoxyribose; D013939:Thymidine Phosphorylase; D011505:Protein-Tyrosine Kinases; D051417:Focal Adhesion Kinase 1; D051416:Focal Adhesion Protein-Tyrosine Kinases; C496050:PTK2 protein, human