SearchPublisher and Institutes
You are here: Home :: Area NEM :: Life sciences :: Biochemistry
Elke Guthaus, Markus Bürgle, Niko Schmiedeberg, Stefan Hocke, Alexandra Eickler, Michael D. Kramer, C.G.J. Fred Sweep, Viktor Magdolen, Horst Kessler, Manfred Schmitt
uPA-Silica-Particles (SP-uPA): A Novel Analytical System to Investigate uPA-uPAR Interaction and to Test Synthetic uPAR Antagonists as Potential Cancer Therapeutics
The urokinasetype plasminogen activation system, including the serine protease uPA (urokinasetype plasminogen activator) and its cell surface receptor (uPAR, CD87), are important key molecules in tumor invasion and metastasis. Besides its proteolytic function, binding of uPA to uPAR on tumor cells exerts various cell responses such as migration, adhesion, proliferation, and differentiation. Hence, the uPA/uPAR system is a potential target for tumor therapy. We have designed a new generation of uPAderived synthetic cyclic peptides suited to interfere with the binding of uPA to uPAR and present a new technology involving micro silica particles coated with uPA (SPuPA) and reacting with recombinant soluble uPAR (suPAR), to rapidly assess the antagonistic potential of uPApeptides by flow cytofluorometry (FACS). For this, we used silica particles of 10 m in diameter to which HMWuPA is coupled using the EDC/NHS method. Soluble, recombinant suPAR was added and the interaction of SPuPA with suPAR verified by reaction with monoclonal antibody HD13.1 directed to uPAR, followed by a cyan dye (cy5)labeled antibody directed against mouse IgG. Thereby it was possible to test naturally occurring ligands of uPAR (HMWuPA, ATF) as well as highly effective, synthetic cyclic uPAderived peptides (cyclo21,29 uPA21 30, cyclo21,29uPA21 30, cyclo21,29[ DCys[21]2-Nal24Cys29]uPA21 30, and cyclo21,29uPA21 30. The results obtained with the noncellular SPuPA/uPAR system are highly comparable to those obtained with a cellular system involving FITCuPA and the promyeloid cell line U937 as the source of uPAR.
Biological Chemistry, Walter de Gruyter
Print ISSN: 1431-6730
Volume: 383, 01/2002
Pages: 207 - 216