Antagonistic anti-urokinase plasminogen activator receptor (uPAR) antibodies significantly inhibit uPAR-mediated cellular signaling and migration.
Interactions between urokinase plasminogen activator receptor (uPAR) and its various ligands regulate tumor growth, invasion, and metastasis. Antibodies that bind specific uPAR epitopes may disrupt these interactions, thereby inhibiting these processes. Using a highly diverse and naïve human fragment of the antigen binding (Fab) phage display library, we identified 12 unique human Fabs that bind uPAR. Two of these antibodies compete against urokinase plasminogen activator (uPA) for uPAR binding, whereas a third competes with beta1 integrins for uPAR binding. These competitive antibodies inhibit uPAR-dependent cell signaling and invasion in the non-small cell lung cancer cell line, H1299. Additionally, the integrin-blocking antibody abrogates uPAR/beta1 integrin-mediated H1299 cell adhesion to fibronectin and vitronectin. This antibody and one of the uPAR/uPA antagonist antibodies shows a significant combined effect in inhibiting cell invasion through Matrigel/Collagen I or Collagen I matrices. Our results indicate that these antagonistic antibodies have potential for the detection and treatment of uPAR-expressing tumors.
Duriseti
Sai
S
Graduate Group in Biophysics, University of California, San Francisco, California 94158-2517.
Goetz
David H
DH
Department of Pharmaceutical Chemistry, University of California, San Francisco, California 94158-2517.
Hostetter
Daniel R
DR
Department of Pharmaceutical Chemistry, University of California, San Francisco, California 94158-2517.
LeBeau
Aaron M
AM
Department of Pharmaceutical Chemistry, University of California, San Francisco, California 94158-2517.
Wei
Ying
Y
Department of Medicine and Cardiovascular Research Institute, University of California, San Francisco, California 94158-2517. Electronic address: ying.wei@ucsf.edu.
Craik
Charles S
CS
Department of Pharmaceutical Chemistry, University of California, San Francisco, California 94158-2517. Electronic address: craik@cgl.ucsf.edu.
D000818:Animals; D000911:Antibodies, Monoclonal; D002289:Carcinoma, Non-Small-Cell Lung / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000187:drug effects* / Q000235:genetics / Q000276:immunology; D006801:Humans; D007140:Immunoglobulin Fab Fragments / Q000235:genetics / Q000276:immunology / Q000494:pharmacology*; D009361:Neoplasm Invasiveness; D009363:Neoplasm Proteins / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D011485:Protein Binding / Q000187:drug effects / Q000235:genetics / Q000276:immunology; D055293:Receptors, Urokinase Plasminogen Activator / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects* / Q000276:immunology; D018411:Spodoptera; D014568:Urokinase-Type Plasminogen Activator / Q000235:genetics / Q000276:immunology / Q000378:metabolism
D000911:Antibodies, Monoclonal; D007140:Immunoglobulin Fab Fragments; D009363:Neoplasm Proteins; D055293:Receptors, Urokinase Plasminogen Activator; D014568:Urokinase-Type Plasminogen Activator