title: Endostatin inhibits the vascular endothelial growth factor-induced mobilization of endothelial progenitor cells.
abstract: Circulating endothelial cells (CECs) are present in peripheral blood and have been shown to contribute to normal and pathological neovascularization. Antiangiogenic molecules can inhibit neovascularization in tumors and other sites, but their effect on CECs has not yet been determined. We hypothesize that angiogenic factors will increase the number of CECs, and conversely, antiangiogenic treatment will reduce these numbers. Mice treated with high levels of vascular endothelial growth factor (VEGF) showed increased numbers of Flk-1-positive cells in peripheral blood and endothelial cell colonies compared with vehicle-treated controls. These changes were accompanied by increased bone marrow neovascularization. In contrast, mice that received VEGF and endostatin had significantly lower numbers of CECs and reduced bone marrow vascularization. Endostatin-induced apoptosis was probably responsible for the decreased number of CECs. Systemic delivery of a VEGF antagonist, soluble Flt-1, also inhibited the VEGF-induced increase in CECs. These results were further confirmed in a Tie2/LacZ mouse model, in which endostatin reduced the number of beta-galactosidase-expressing peripheral blood mononuclear cells. We propose that endothelial progenitor cells are a novel target for endostatin and suggest that the relative numbers of CECs can serve as a surrogate marker for the biological activity of antiangiogenic treatment.
authors.affiliation: Department of Urology, Children's Hospital, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts 02115, USA.
authors.forename: Gunter
authors.initials: G
authors.lastname: Schuch
authors.forename: John V
authors.initials: JV
authors.lastname: Heymach
authors.forename: Masashi
authors.initials: M
authors.lastname: Nomi
authors.forename: Marcelle
authors.initials: M
authors.lastname: Machluf
authors.forename: Jeremy
authors.initials: J
authors.lastname: Force
authors.forename: Anthony
authors.initials: A
authors.lastname: Atala
authors.forename: Joseph P
authors.initials: JP
authors.lastname: Eder
authors.forename: Judah
authors.initials: J
authors.lastname: Folkman
authors.forename: Shay
authors.initials: S
authors.lastname: Soker
mesh_terms: D000818:Animals; D002465:Cell Movement / Q000187:drug effects* / Q000502:physiology; D043169:Endostatins / Q000008:administration & dosage / Q000096:biosynthesis / Q000235:genetics / Q000494:pharmacology*; D004730:Endothelium, Vascular / Q000166:cytology* / Q000187:drug effects; D006801:Humans; D051379:Mice; D016513:Mice, SCID; D008822:Mice, Transgenic; D013234:Stem Cells / Q000166:cytology* / Q000187:drug effects; D042461:Vascular Endothelial Growth Factor A / Q000037:antagonists & inhibitors / Q000494:pharmacology / Q000502:physiology*
chemical_list: D043169:Endostatins; D042461:Vascular Endothelial Growth Factor A