title: Cells of the human myelomonocytic line RC-2A synthesize tissue factor-like procoagulant and urokinase-type plasminogen activator.
abstract: Cells of the myelomonocytic leukemia cell line RC-2A were studied for their ability to synthesize clotting-promoting and fibrinolytic factors. The cells were observed to generate procoagulant activity (PCA) in readily measurable quantities. Incubation of RC-2A cells with phorbol myristate acetate (PMA; 3 ng/ml) or phytohemagglutinin (PHA, 10 micrograms/ml) for 18 h resulted in a 4-5-fold increase in PCA relative to unstimulated control. The PCA of RC-2A cells was tissue factor-like in that it was dependent on factor VII but not on factors VIII or IX. RC-2A cells also produced plasminogen activator (PA). Secreted PA was approximately 70% of the PA of an identical number of human monocyte-derived macrophages; fresh isolated monocytes synthesized virtually no PA. Compared to macrophages, RC-2A cells secreted less or no PA-inhibitors. Lysates of RC-2A cells contained over three times more PA than lysed macrophages. Stimulation of the cells with lectins (PHA, concanavalin A) or PMA was followed by a modest (2-3-fold) increase in PA. Enzyme immunoassay with antibodies to urokinase (u-PA) or tissue-type PA (t-PA) identified the RC-2A plasminogen activator as being of urokinase type.
authors.forename: E
authors.initials: E
authors.lastname: Karhumäki
authors.forename: L
authors.initials: L
authors.lastname: Saravo
authors.forename: H
authors.initials: H
authors.lastname: Helin
mesh_terms: D001779:Blood Coagulation Factors / Q000096:biosynthesis*; D002460:Cell Line; D003208:Concanavalin A / Q000494:pharmacology; D005167:Factor VII / Q000494:pharmacology; D006023:Glycoproteins / Q000378:metabolism; D006098:Granulocytes / Q000378:metabolism*; D006801:Humans; D007124:Immunoenzyme Techniques; D008264:Macrophages / Q000378:metabolism*; D009000:Monocytes / Q000378:metabolism*; D010835:Phytohemagglutinins / Q000494:pharmacology; D015849:Plasminogen Inactivators; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014568:Urokinase-Type Plasminogen Activator / Q000096:biosynthesis*
chemical_list: D001779:Blood Coagulation Factors; D006023:Glycoproteins; D010835:Phytohemagglutinins; D015849:Plasminogen Inactivators; C045071:leukocyte procoagulant activity; D003208:Concanavalin A; D005167:Factor VII; D014568:Urokinase-Type Plasminogen Activator; D013755:Tetradecanoylphorbol Acetate