Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.21.7 (plasmin)
 9,023 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

This report describes the purification and characterization of single-chain tissue-type plasminogen activator (sct-PA) present in tissue culture medium of a cell line established from human uterine muscle. The cell line used for the experiment, KW, had estrogen receptor. The PA fraction (KW-PA) was purified from the tissue culture medium of KW employing several steps of affinity chromatography and gel filtration in the presence of aprotinin. The final product (KW-PA) of purification, which predominantly contained the inactive form of sct-PA as well as active sct-PA to a lesser extent, revealed a single band with a molecular weight of 70,000 on sodium dodecyl sulphate (SDS) polyacrylamide gel electrophoresis both in the absence and presence of reducing agent. Electrophoretic enzymography demonstrated a single lytic zone at Mr 70,000. When KW-sct-PA was treated with plasmin, SDS-polyacrylamide gel electrophoresis revealed two bands of Mr 37,000 and 33,000 under reduced conditions. Such plasmin treatment of KW-sct-PA enhanced the enzymatic activity as well as the [3H]DFP incorporation significantly. The KW-sct-PA demonstrated a higher affinity for lysine than did melanoma-t-PA, but the fibrin affinity of KW-sct-PA was identical with that of melanoma-t-PA. Circular dichroism (CD) analysis showed that the CD spectra of KW-sct-PA were different from those of melanoma-t-PA. These results suggest that the single-chain inactive form of t-PA which was obtained from the tissue culture medium of the cell line from human uterine muscle is activated to a two-chain form on plasmin treatment, with an accompanying significant increase in enzymatic activity.
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PMID:Production and characterization of single-chain tissue-type plasminogen activator produced by an established cell line from human uterine muscle. 249 95

Plasminogen activator is a protease which catalyses the conversion of the inactive plasminogen to the active plasmin. Most transformed cell lines and solid tumors produce elevated levels of plasminogen activator compared with nontransformed counterparts. This increased synthesis of plasminogen activator may play a role in tumorigenesis, cancer invasion and metastasis. Measurement of plasminogen activator in tumor extracts and body fluids may provide diagnostic and prognostic information. Finally, since plasminogen activator is an estradiol-inducible enzyme, its measurement in breast carcinomas might be a marker for a functional estrogen receptor.
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PMID:Plasminogen activator and cancer. 637 29

Urokinase-type plasminogen activator (u-PA), which cleaves plasminogen to yield plasmin, is a serine protease of fibrinolysis and is presumed to play a key role in extracellular proteolysis and facilitate the migration of cancer cells. This study was conducted prospectively to evaluate the prognostic significance of u-PA antigen level in breast cancer tissues. u-PA concentrations in the cytosol of 226 breast cancer tissues were determined prospectively by enzyme-linked immunosorbent assay using cytosol fractions prepared for steroid hormone assay. The median follow-up period of the patients was 60 months. Various prognostic factors were evaluated by univariate analysis or multivariate analysis using the Cox proportional-hazards method. Patients with primary breast cancer containing high levels of u-PA had a significantly shorter disease-free survival than patients with low levels of u-PA antigens. In multivariate analysis, a high level of u-PA was an independent risk factor for disease-free survival, being independent of age, axillary node status, and estrogen receptor status. Among the major prognostic factors, a high u-PA antigen level, lymph node involvement, and a positive estrogen receptor status were the most important for predicting relapse-free survival (P = 0.044, P < 0.0001, P = 0.0039). This first prospective study confirmed the prognostic significance of the u-PA antigen level in association with other major prognostic factors. The results of our present study suggest that u-PA in breast cancer tissue might be involved in breast cancer invasion and metastasis.
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PMID:A prospective study on the prognostic significance of urokinase-type plasminogen activator levels in breast cancer tissue. 939 89

Plasminogen activators are known to be involved in the metastatic spread of breast cancer. In the present study we examined the effects of antiestrogens [Analog II (1,1-dichloro-cis-2,3-diphenyl cyclopropane) (AII), ICI-182,780 (ICI) and tamoxifen (TAM)], on the in vitro release of uPA from estrogen receptor (ER)-positive MCF-7 (MCF) and ER-negative MDA-MB-231 (MDA) human breast cancer cell lines. Using a solid-phase radioassay, uPA activity was found to be higher in the culture medium from MDA cells compared to MCF cells. Aminocaproic acid, a specific plasmin inhibitor, produced a 50-60% reduction in the degradation of labeled substrate, in the solid phase assay, using culture medium from both cell lines, thus indicating that most of the proteolysis observed was due to uPA-mediated plasmin generation from plasminogen. In the absence of plasminogen, the enzyme activity was not detected in either the quantitative assay or by zymography. In MDA cells, uPA release was not altered by any of the antiestrogens used alone or in the presence of estradiol. In contrast, in MCF cells, ICI alone produced maximal inhibition (40%) of enzyme release, while estradiol alone produced a 120% increase in enzyme activity. When co-administered with estradiol, in MCF cultures, each antiestrogen reduced enzyme activity to control levels. Substrate gel zymography revealed that the urokinase-type PA is the predominant form of PA released by both cell lines. Comparison of the activity of all three antiestrogens used in this study indicates that ICI is the most potent inhibitor of enzyme activity in ER-positive MCF cells.
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PMID:The influence of antiestrogens on the release of plasminogen activator (uPA) by MDA-MB-231 and MCF-7 breast cancer cells. 956 41

We have recently described the urokinase-type plasminogen activator (uPA) and its type 1 inhibitor (PAI-1) as strong prognostic variables in breast cancer (J. A. Foekens et al., Cancer Res., 52: 6101-6105, 1992; J. Grondahl-Hansen et al., Cancer Res., 53: 2513-2521, 1993; J. A. Foekens et al., J. Clin. Oncol., 11: 899-908, 1994). A specific cell surface receptor (uPAR) binds uPA and strongly enhances plasmin generation, and the amount of uPAR in the tumor tissue might therefore be a rate-limiting factor in the extracellular proteolysis involved in tumor invasion. Here, we report on the prognostic value of uPAR in cytosolic (uPARc) and Triton (uPARt) extracts prepared from 505 primary breast tumors. The median observation time was 54 (range: 12-125) months. uPAR levels were determined by a sandwich ELISA. Univariate analysis showed that high uPAR levels (above the median value) were significantly associated with a shorter overall survival, showing a stronger discriminatory effect for uPARc [relative hazard rate (RHR): 1.47; P = 0.012)] as compared with uPARt (RHR, 1.33; P = 0.059), while no statistically significant differences were found for relapse-free survival. Multivariate analysis including all patients showed that when including other biochemical variables (estrogen receptor, progesterone receptor, PS2, cathepsin D, uPA, and PAI-1), the only retained independent variable via backward elimination was PAI-1 for both relapse-free survival and overall survival. When analyzed separately in clinically relevant subgroups, the prognostic value of uPAR was particularly strong in a subgroup of 201 node-positive postmenopausal women, showing considerably shorter overall (RHR: 2.39; P < 0.0001) and relapse free (RHR: 1.91; P = 0.0006) survival for patients with high uPARc content. High uPARt levels were also significantly associated with shorter overall survival in this subgroup of patients (RHR: 1.5; P = 0.047), but not with relapse-free survival (P = 0.64). Multivariate analysis, including the basic model, estrogen and progesterone receptors, PS2, cathepsin D, uPA, PAI-1, uPARc, and uPARt in the subgroup of postmenopausal node-positive patients, showed that only uPARc and PAI-1 were significant independent prognostic parameters, with respect to overall survival, RHRs being 2.72 (P < 0.0001) and 1.81 (P = 0.005), respectively. In multivariate analysis of relapse-free survival, uPARc, PAI-1, and uPA were independent parameters with respective relative relapse rates of 1.91 (P = 0.002) for uPARc, 1.68 (P = 0.02) for PAI-1, and 1.6 (P = 0.03) for uPA. These data lend support to the hypothesis that uPAR is an important molecule in plasmin-mediated extracellular matrix degradation leading to cancer cell dissemination and death of the patient.
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PMID:Prognostic significance of the receptor for urokinase plasminogen activator in breast cancer. 981 97

Serine proteases convert plasminogen to plasmin which is involved in tissue remodeling under physiologic and pathophysiologic conditions, including breast carcinoma invasion and progression. Both urokinase-type plasminogen activator (uPA) and pro-uPA associate with uPA receptor (uPAR) on target cells, where plasminogen activator inhibitors (e.g., PAI-1) may modulate their activities. Expression levels of these factors were compared in breast carcinomas relative to patient characteristics, carcinoma features, and clinical outcome. uPA, uPAR, and PAI-1 were quantified by enzyme-linked immunosorbent assay (ELISA) in extracts of 226 biopsies while estrogen receptor (ER) and progestin receptor (PR) were determined by enzyme immunoassay (EIA) or radio-ligand binding. Each set of assays contained a novel reference specimen with known quantities of each of these five analytes. Levels in ng/mg protein of these biomarkers exhibited ranges: uPA (0-12.3); uPAR (0-19.5); PAI-1 (0-91.2). When considered independently, expression of uPA, uPAR, or PAI-1 was unrelated to patient age or menopausal status. Although no correlation was observed between each analyte with stage, grade, or ER/PR status, levels appeared to differ with pathology and nodal status. A dendrogram from hierarchical clustering of uPA, uPAR, and PAI-1 levels in 106 specimens revealed three clusters of breast cancer patients. Kaplan-Meier analyses of uPA, uPAR, and PAI-1 indicated a correlation with overall survival (OS), suggesting collective examination of these biomarkers is useful in predicting clinical outcome of breast cancer.
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PMID:Expression of urokinase-type plasminogen activator (uPA), its receptor (uPAR), and inhibitor (PAI-1) in human breast carcinomas and their clinical relevance. 2246 24