title: Probing for integrin alpha v beta3 binding of RGD peptides using fluorescence polarization.
abstract: Integrin alpha(v)beta(3) is an adhesion molecule involved in tumor invasion, angiogenesis, and metastasis. There is substantial interest in developing novel agents that bind to integrin alpha(v)beta(3). Here we report the synthesis and characterization of a fluorescent integrin alpha(v)beta(3) probe and its use in a nonradioactive, simple, sensitive fluorescence polarization (FP) assay to quantify binding to integrin alpha(v)beta(3). For assay validation, the FP assay was compared to a cell adhesion assay. In the two assays, probe binding to integrin alpha(v)beta(3) showed a similar dependence on probe concentration. The FP assay was successfully applied to measure the binding affinity to integrin alpha(v)beta(3) of several cyclic peptides containing the Arg-Gly-Asp (RGD) motif. The FP assay we describe here may be appropriate for high-throughput screening for integrin alpha(v)beta(3)-binding ligands used for anti-integrin therapy or noninvasive imaging of integrin expression.
authors.affiliation: Department of Experimental Diagnostic Imaging, The University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030, USA.
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.forename: Qingping
authors.initials: Q
authors.lastname: Wu
authors.forename: Marites
authors.initials: M
authors.lastname: Pasuelo
authors.forename: John S
authors.initials: JS
authors.lastname: McMurray
authors.forename: Chun
authors.initials: C
authors.lastname: Li
mesh_terms: D002448:Cell Adhesion / Q000187:drug effects; D045744:Cell Line, Tumor; D005452:Fluoresceins / Q000737:chemistry; D005454:Fluorescence Polarization / Q000379:methods*; D006801:Humans; D020128:Inhibitory Concentration 50; D039302:Integrin alphaVbeta3 / Q000737:chemistry / Q000378:metabolism*; D008545:Melanoma / Q000378:metabolism / Q000473:pathology; D015394:Molecular Structure; D009842:Oligopeptides / Q000737:chemistry / Q000378:metabolism*; D010456:Peptides, Cyclic / Q000494:pharmacology; D011485:Protein Binding; D017186:Titrimetry; D019096:Vitronectin / Q000494:pharmacology
chemical_list: D005452:Fluoresceins; D039302:Integrin alphaVbeta3; D009842:Oligopeptides; D010456:Peptides, Cyclic; D019096:Vitronectin; C024098:6-carboxyfluorescein; C047981:arginyl-glycyl-aspartic acid