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Journal of Biomedicine and Biotechnology
Volume 2012 (2012), Article ID 984589, 7 pages
http://dx.doi.org/10.1155/2012/984589
Research Article

Characterization of Plasminogen Binding to NB4 Promyelocytic Cells Using Monoclonal Antibodies against Receptor-Induced Binding Sites in Cell-Bound Plasminogen

1Cell Biology Department, Pompeu Fabra University, Barcelona, Spain
2Centre de Diagnòstic Genètic Molecular, Hospital Duran i Reynals, 08907 L'Hospitalet de Llobregat, Spain
3Centre Atenció Primària (CAP) Canaletes, Institut Català de la Salut (ICS), Passeig d'Horta 17, 08290 Cerdanyola del Vallès, Spain

Received 24 April 2012; Accepted 6 June 2012

Academic Editor: Lindsey A. Miles

Copyright © 2012 Mercè Jardí et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The NB4 promyelocytic cell line exhibits many of the characteristics of acute promyelocytic leukemia blast cells, including the translocation (15 : 17) that fuses the PML gene on chromosome 15 to the RARα gene on chromosome 17. These cells have a very high fibrinolytic capacity. In addition to a high secretion of urokinase, NB4 cells exhibit a 10-fold higher plasminogen binding capacity compared with other leukemic cell lines. When tissue-type plasminogen activator was added to acid-treated cells, plasmin generation was 20–26-fold higher than that generated by U937 cells or peripheral blood neutrophils, respectively. We found that plasminogen bound to these cells can be detected by fluorescence-activated cell sorting using an antiplasminogen monoclonal antibody that specifically reacts with this antigen when it is bound to cell surfaces. All-trans retinoid acid treatment of NB4 cells markedly decreased the binding of this monoclonal antibody. This cell line constitutes a unique model to explore plasminogen binding and activation on cell surfaces that can be modulated by all-trans retinoid acid treatment.