Fibrinolytic activity of in vitro cultivated human bladder cell lines

Three human bladder carcinoma cell lines, T 24, RT 4, and MANO, a human bladder nonmalignant epithelial cell line, HCV-29, and a human lung fibroblast line, 460 H1, were investigated for their ability to induce fibrinolytic, urokinase and plasmin inhibitory activities in cell culture, using serum-free medium, for up to 36 h. Generally, the non-malignant cell line and the fibroblast line had a greater ability to produce urokinase inhibitor than did the malignant cell lines. The amount produced varied greatly between cells and over the study period. A low concentration of plasminogen activator, immunologically identical with urokinase, and its accumulation in culture supernate were found with RT 4 after 12 h and 24 h cultivations, whereas no plasminogen activator was detected in all other cell lines for periods up to 36 h. No plasmin, non-specific protease or plasmin inhibitory activities were detected in any of the supernates from the cell lines.