Active and pro-plasminogen activator on the surface of human bladder cancer cells derived from a high grade invasive tumour.

Intact UCRU-BL28 cells derived from a high grade invasive human bladder cancer produced both active and pro-plasminogen activator. Following culture of cells in the presence of plasminogen, all of the pro-plasminogen activator was converted to an active form. Cell-surface extracts showed plasminogen activator activity with a molecular mass of 55,000, similar to that of human urokinase. Extracts also contained gelatinase activities with molecular masses of 101,000; 80,000; 74,000 and 70,000 in polyacrylamide gel electrophoresis. These tumour cell-surface proteinases may be involved in invasion and metastasis in human bladder cancer.