MMP-9 and MMP-2 activities in stomach and breast tumours, as measured by a novel MMP activity assay using modified urokinase as a substrate
article
Matrix metalloproteinases (MMPs) play an important role in many pathological processes. However, MMP activities are difficult to determine since no simple specific and/or chromogenic substrates exist. Therefore, we have developed a novel MMP activity assay using a modified urokinase as a substrate. In this urokinase, as obtained by protein engineering, the plasmin activation site was substituted by an activation site which is only specifically recognized by MMPs. In this way the MMP activity can be monitored via urokinase activity as measured by a simple chromogenic assay. The assay was made specific for either MMP-2 or MMP-9 by a catching step using specific MMP-2 or MMP-9 antibodies that do not interfere with MMP-activity. Both active (directly) and latent MMP (after activation with APMA) can be monitored. Using these assays it was observed that tissue homogenates contained hardly any active MMP-9. However, after activation by APMA tumor tissue homogenates from the stomach contained a higher MMP-9 activity compared to healthy tissue from the stomach. MMP-2 activity was hardly detectable in both tumor and normal tissue. In tissue homogenates from malign and benign breast tumours it was observed that homogenates from malignant tissue contained significantly more MMP-9, both in active and latent form. No differences were observed for MMP-2. These results suggest that in breast and stomach tumors MMP-9, but not MMP-2, might play an important role in tumour pathology.
TNO Identifier
234746
ISSN
13690191
Source
Fibrinolysis and Proteolysis, 12(SUPPL. 1), pp. 30.
Pages
30
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