title: Novel highly efficient intrabody mediates complete inhibition of cell surface expression of the human vascular endothelial growth factor receptor-2 (VEGFR-2/KDR).
abstract: The human vascular endothelial growth factor receptor-2 (VEGFR-2/KDR) and its ligand vascular endothelial growth factor (VEGF) play an essential role in tumor angiogenesis and in haematological malignancies. To inhibit VEGF induced signalling, intrabodies derived from two scFv fragments recognizing the VEGF receptor were generated. When these intrabodies were expressed in endothelial cells, they blocked the transport of KDR to the cell surface. We developed a cell culture model using porcine aortic endothelial cells overexpressing KDR for testing the efficiency of anti-KDR intrabodies. The two intrabodies were targeted to the ER and colocalized with the KDR receptor in an intracellular compartment. No degradation of the receptor was observed. An immature incomplete glycosylated protein of 195 kDa was detected, suggesting that the intrabodies affect the maturation of the receptor. Despite the presence of significant amounts of receptor protein, the inactivation by one of the two intrabodies was highly effective, resulting in complete functional inhibition of KDR and inhibition of in vitro angiogenesis. The new intrabody appears to be a powerful tool with which to inhibit KDR function.
authors.affiliation: Gesellschaft für Biotechnologische Forschung mbH, Department of Gene Regulation and Differentiation, Mascheroder Weg 1, D-38124 Braunschweig, Germany. tbo@gbf.de
authors.forename: Thomas
authors.initials: T
authors.lastname: Böldicke
authors.forename: Holger
authors.initials: H
authors.lastname: Weber
authors.forename: Peter P
authors.initials: PP
authors.lastname: Mueller
authors.forename: Bernhard
authors.initials: B
authors.lastname: Barleon
authors.forename: Maria
authors.initials: M
authors.lastname: Bernal
mesh_terms: D000818:Animals; D000906:Antibodies; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D006224:Cricetinae; D004730:Endothelium, Vascular / Q000254:growth & development / Q000378:metabolism; D015870:Gene Expression; D006031:Glycosylation; D006801:Humans; D007128:Immunoglobulin Fragments / Q000235:genetics / Q000378:metabolism*; D066298:In Vitro Techniques; D008970:Molecular Weight; D018919:Neovascularization, Physiologic; D011994:Recombinant Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000276:immunology / Q000378:metabolism; D015398:Signal Transduction; D013552:Swine; D014162:Transfection; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000276:immunology / Q000378:metabolism
chemical_list: D000906:Antibodies; D007128:Immunoglobulin Fragments; D011994:Recombinant Proteins; C055966:immunoglobulin Fv; D040301:Vascular Endothelial Growth Factor Receptor-2