Measurement of plasminogen activator activity from human fibrosarcoma cells by a new microassay

✍ Scribed by M. Rezaee; L. Chen; R. H. Kramer

• Publisher: John Wiley and Sons
• Year: 1987
• Tongue: French
• Weight: 775 KB
• Volume: 40
• Category: Article
• ISSN: 0020-7136
• DOI: 10.1002/ijc.2910400620

✦ Synopsis

Elevated levels of plasminogen activator (PA) activity have been correlated with neoplasia and may have an important role in tumor-cell invasion and metastasis. We have developed a new caseinolytic assay that uses an immunochemical approach to measure the activity of PA elaborated by malignant tumor cells. The highly sensitive assay consists in incubating a source of PA (viable tumor cells, cell extracts, or conditioned medium) with purified plasminogen in microtiter plates precoated with a suitable protein substrate such as casein. Clearance of the immobilized protein substrate by PA-generated plasmin is then measured by a technique based on the enzyme-linked immunosorbent assay. In experiments using urokinase as a source of PA, the assay displayed near linearity over several log units of urokinase activity and could detect as little as 10-2 Ploug units of PA activity. Besides successfully measuring PA activity produced by the human HT1080 fibrosarcoma cell line, the assay permitted detection of significant plasminogen-independent proteolytic activity generated by intact tumor cells cultured in direct contact with immobilized protein substrates.