Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0006142 (breast cancer)
 160,383 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Urokinase-type plasminogen activator (uPA) initiates an extracellular proteolytic cascade with which invasive cells eliminate barriers to movement. We have evaluated the antiinvasive and antimetastatic properties of two recently developed synthetic uPA inhibitors, B428 and B623, in a BALB/c mouse mammary carcinoma model. We used the F3II and M3 tumor cell lines, previously described by our laboratory. In vitro, noncytotoxic concentrations of B428 or B623 inhibited secreted and cell-associated uPA activity produced by tumor cells and blocked uPA-mediated whole tumor cell degradation of fibronectin, allowing deposition of extracellular fibronectin fibrils. In vivo, administration of compounds was not associated with overt toxic effects. Daily i.p. treatment with B428 (20 mg/kg/day) or B623 (7.5 mg/kg/day) for 2 weeks, beginning after tumor take, markedly blocked the invasion of the muscle and adipose layers of the subcutis and dermis in mice bearing highly invasive F3II tumors. However, these compounds neither inhibited tumor-induced angiogenesis nor reduced the incidence of spontaneous lung metastasis. Moreover, B623 enhanced the formation of experimental lung metastasis. Our results suggest that synthetic uPA inhibitors act as potent antiinvasiveness agents in vivo but may be unable to control progression of the metastatic disease in the present mammary tumor model.
Breast Cancer Res Treat 1996
PMID:Effects of synthetic urokinase inhibitors on local invasion and metastasis in a murine mammary tumor model. 888 63

The conversion of plasminogen to active plasmin is thought to be a crucial step in the process of extracellular matrix degradation associated with metastatic spread. Activation of plasminogen is initiated by urokinase plasminogen activator (uPA). The binding of uPA to the uPA cell surface receptor (uPA-R) accelerates plasmin generation from plasminogen and localizes uPA activity to the cell surface. We investigated the mRNA-expression of uPA-R in 19 different human breast cancer cell lines. In a competitive reverse transcription polymerase chain reaction (cRT-PCR) we simultaneously co-amplified two different RNA templates bearing the same primer recognition sequences, the cell line RNA and a known amount of an in vitro synthesized uPA-R-RNA internal standard. We analyzed the two PCR products differing 50 bp in size by agarose gel electrophoresis and calculated the initial uPA-R-RNA template concentration from the relative intensities of the bands quantified by video densitometry. We grouped the investigated cell lines according to their in vitro invasiveness according to literature. Cell lines with a high potential of invasiveness showed a higher expression of uPA-R compared to those with a low potential of invasiveness (Student's t-test, p 0.04). In addition to that we compared the uPA-R mRNA levels with uPA-R, uPA, and PAI-1 protein levels in culture supernatants and cell lysates. The obtained results in breast cancer cell lines with different invasiveness and in benign epithelial cell lines revealed the complex cooperation of the urokinase type proteolytic pathway. uPA, uPA-R, and PAI-1 are to be considered as a diagnostic tool rather than assaying a particular molecule alone. Our findings support the hypothesis that the urokinase proteolytic pathway plays a central role in the acquisition of an invasive phenotype and favors its potential use as a prognostic marker in patients with breast cancer.
Breast Cancer Res Treat 1996
PMID:Quantification of uPA receptor expression in human breast cancer cell lines by cRT-PCR. 888 68

We inoculated the KLE human endometrial cancer, MCF-7 and ZR-75 human breast cancer, and PC-3 human prostate cancer cells into three-dimensional type I collagen gel system that contained uniformy dispersed MG-63 osteoblast-like cells. Then, we analyzed the morphological evidence of osteoblasts reaction, local invasion around the inoculated cancer cells and expression of the cathepsin D and urokinase-type plasminogen activator (uPA) around the sites of inoculation using immunocytochemistry. The prostate cancer cells produced morphological evidence of blastic reaction presented as an increased number of MG-63 osteoblasts and increase density of type I collagen around the sites of inoculation with PC-3 cells. The inoculated MCF-7 and ZR-75 cells decreased the density of type I collagen and number of osteoblasts and invaded the collagen gel around the sites of inoculation. The KLE endometrial cancer cells and cell-free media produced no reaction at the inoculation sites suggestive of cancer cell-specific interactions with osteoblasts in this system. The expression of uPA was remarkably higher at the inoculation sites of PC-3 cells as compared with those of the other cancer cells. Cathepsin D expression was higher at the sites of inoculation with KLE, MCF-7 and PC-3 cancer cells. MG-63 osteoblasts contained relatively low expression of uPA and cathepsin D. We conclude that this collagen gel system is a useful model for studying the morphological evidence of local invasion and osteoblasts reaction produced in response to local growth of metastatic cancer cell in vitro.
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PMID:Three-dimensional type I collagen gel system containing MG-63 osteoblasts-like cells as a model for studying local bone reaction caused by metastatic cancer cells. 891 85

The levels of uPA, its inhibitors PAI-1 and PAI-2, and the uPA receptor (uPAR) have prognostic value in breast cancer. However, different extraction methods and assays kits are used in different laboratories and may directly influence the levels observed. To define a buffer suitable for both PAI-2 and uPAR extraction from breast cancer tissue compatible with hormone receptors and other cytosolic prognosticator assays, we compared PAI-2 and uPAR values obtained by immunoenzymatic assays (American Diagnostica, Greenwhich, USA) in several extraction conditions: 1) cytosol obtained with the standard hormone receptor buffer; 2) solubilized pellets obtained by Triton X100 extraction of the pelleted membranes obtained with standard hormone receptor buffer; 3) cytosol obtained by direct extraction in the buffer (containing Triton X100) recommended by the manufacturer, after 2 hours or 12 hours of incubation. Cytosol extracts prepared using the standard procedure recommended for hormone receptors gave the highest PAI-2 values. The highest uPAR values were obtained in the subsequent detergent extraction of the pelleted membranes. PAI-2 levels obtained with the kit manufacturer's method after 12 hours of incubation were lower than those obtained after 2 hours of incubation, whereas uPAR levels were similar. We conclude that the most suitable extraction protocol employs standard hormone receptor extraction buffer to obtain a supernatant cytosol fraction for PAI-2 assay, and subsequent detergent extraction of the pelleted membranes to obtain an extract suitable for uPAR.
Breast Cancer Res Treat 1996
PMID:Influence of the extraction procedure on plasminogen activator inhibitor-2 (PAI-2) and urokinase receptor (uPAR) assays in breast cancer tissues. 894 32

The relative importance of different proteinases, and their inhibition, in the breakdown of human endothelial basement membrane (BM) by MDA-MB-231 and MCF7ADR human breast cancer cell lines has been studied using 35S-labelled BM-coated 96-well culture plates. Basement membrane degradation (BMD) was independent of cell proliferation above the seeding density. Inhibitors of aspartic (pepstatin and PD 134678-0073) and cysteine proteinases (E64) had little effect on BMD under normal culture conditions, suggesting that cathepsins D, B and L have only a minor role. In contrast, inhibitors of urokinase-type plasminogen activator (uPA) and/or plasminogen activation to plasmin (aprotinin, amiloride, EACA, tranexamic acid, anti-uPA antibody) all reduced BMD by MDA-MB-231 cells by approximately 30-40%, but only in the presence of serum or plasminogen. BB94, an inhibitor of matrix metalloproteinases (MMPs), also reduced BMD by about 30% under these conditions but was similarly effective in serum-free medium. Combinations of BB94 with any of the uPA/plasminogen activation inhibitors in serum-containing medium had additive effects, while BB94 with pepstatin and E64 under serum-free conditions reduced BMD to 16% of control. Serum-containing conditioned medium exhibited appreciable BMD, largely due to aprotinin-inhibitable activity. Although small reductions in cell proliferation were seen with some inhibitors, the combination of BB94 with E64 or E64d reduced the cell population by about 60% under serum-containing conditions. These in vitro observations suggest that combinations of proteinase inhibitors, particularly of uPA/plasminogen activation and MMPs, may merit clinical evaluation as potential antimetastatic therapy for breast cancer.
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PMID:Proteinase inhibitors reduce basement membrane degradation by human breast cancer cell lines. 908 29

During activation of the fibrinolytic system plasminogen is converted to plasmin by tissue plasminogen activator (t-PA) or urokinase-type plasminogen activator (u-PA). t-PA is predominantly released from endothelial cells, u-PA primarily by renal parenchymal cells. The activation of plasminogen is regulated by plasminogen activator inhibitor-1 (PAI-1), plasmin is controlled by alpha 2-plasmin inhibitor. The fibrinolytic system is not only involved in the intravascular dissolution of fibrin (thrombi), it also plays a vital role in normal physiologic reproduction, wound repair, angiogenesis, and tissue remodeling. Fibrinolysis is also a vital component in the pathogenesis of neoplastic disease. It is essential in releasing cells from their primary site of origin, providing nutrition for neoplastic cell growth and promoting cell mobility and motility. In neoplastic cells the degradation of the extracellular matrix proteins is facilitated by excessive expression of u-PA, t-PA, and u-PAR. In many forms of carcinoma increased expression of u-PAR and u-PA is associated with significantly shorter survival. Greater expression of u-PA in breast cancer cells, for example, is associated with shorter survival and increased relapse rate. Progressively aggressive neoplastic cells evidence high expression of u-PA and u-PAR activities, variable expression of t-PA, and enhanced PAI-1 and PAI-2 activities. In acute nonlymphocytic leukemias, poor outcome correlates with high t-PA levels. In acute progranulocytic leukemia there is a high incidence of DIC. Neoplastic prostatic tissue also expresses high u-PA activity and the more aggressive the cell line, the greater the number of u-PAR and the higher the u-PA activity. In gynecologic malignancies, a greater expression of u-PA in combination with cathepsin D is associated with widespread disease and poor prognosis. High u-PA values were also seen in patients with brain, gastric, and hepatic malignancies. It is evident that the plasminogen-plasmin system is a vital component in the biology of neoplastic disease and that it is, in theses conditions, in no way beneficial to the host.
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PMID:The fibrinolytic system in neoplasia. 912 11

Cancer cell invasion is accomplished by the concerted action of several extracellular proteolytic enzyme systems, one of which is the urokinase plasminogen activation system. The different components of this system. e.g. urokinase plasminogen activator (uPA), its receptor uPAR, as well as its main inhibitor plasminogen activator inhibitor type 1 (PAI-1) have all been shown to have prognostic value in breast cancer, i.e. high tumor levels are associated with a poor prognosis. In order to further substantiate the prognostic value of uPA and PAI-1, we have tested the cutpoints (median values and optimized outpoints) from our first study (Cancer Res 53: 2513-2521, 1993) in an independent group of breast cancer patients. Breast cancer cytosols from 100 premenopausal and 150 post-menopausal node positive patients were included. The median observation time was 80 months (range 49-145). Univariate analysis showed that high PAI-1 levels (above the median PAI-1 value) were significantly associated with short recurrence-free survival (RR: 1.65; 95% CI: 1.04-2.63; P = 0.03) and short overall survival (RR: 2.46; 95% CI: 1.52-3.96; P = 0.0001) in postmenopausal patients. Postmenopausal patients with high uPA levels (above the median uPA value) had a significantly shorter recurrence-free survival (RR: 2.04; 95% CI: 1.17-3.56; P = 0.01) and overall survival (RR: 2.07; 95% CI: 1.16-3.70; P = 0.01) than patients with low uPA values. Nearly identical results were obtained when using the optimized PAI-1 or uPA value. In a Cox multivariate analysis which included other established prognostic factors, high PAI-1 was found to be an independent prognostic variable predicting short overall survival with a relative risk of 2.27 in postmenopausal women, and high uPA was found to be an independent prognostic variable predicting short recurrence-free survival with a relative risk of 1.86 in postmenopausal women. The present study indicates that uPA and PAI-1 are independent and significant prognostic variables in subsets of breast cancer patients.
Breast Cancer Res Treat 1997 Apr
PMID:Prognostic significance of PAI-1 and uPA in cytosolic extracts obtained from node-positive breast cancer patients. 913 Dec 71

uPA and PAI-1 are becoming established as amongst the most effective markers of poor prognosis for patients with node-negative breast cancer; tPA is an index of longer survival. This paper describes a sensitive ELISA for the measurement of uPA, tPA and PAI-1 in breast cancer cytosols. The structure of the assay involves coating Ab (sheep alpha-Chicken IgY), catching Ab (chicken alpha-analyte), tagging Ab (rabbit alpha-analyte) and detecting Ab (goat alpha-rabbit IgG) labelled with HRP. The assay has a high degree of accuracy and specificity. Comparison with the American Diagnostic kits shows the results' equivalence for PAI-1 and tPA. For uPA the results of the assay were twice as high. The assay is sensitive and relatively inexpensive. It is the first published assay to yield strictly comparative values for uPA, tPA and PAI-1 in tissue extracts and is readily subject to external quality control.
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PMID:A sensitive and robust assay for urokinase and tissue-type plasminogen activators (uPA and tPA) and their inhibitor type I (PAI-1) in breast tumor cytosols. 917 11

MCF7 and ZR75-1 breast cancer cells grow as adherent monolayers in tissue culture. Treatment with the serum serine protease plasmin causes them to detach and to grow as floating multicellular spheroids. Two plasmin activators, urokinase plasminogen activator and streptokinase, induce the same growth pattern changes in the presence of plasminogen. Serum contains also plasminogen activator inhibitors. Aged serum, deficient in plasminogen activator inhibitors, converts spontaneously monolayer breast cancer cells into multicellular spheroids which readily revert to monolayer growth after addition of fresh serum. Urokinase blocks the reversion. The formation of multicellular spheroids does not affect the proliferative rate of breast tumor cells but endows tumor cells with increased resistance to the chemotherapeutic drugs, doxorubicin and paclitaxel.
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PMID:Plasmin induces the formation of multicellular spheroids of breast cancer cells. 923 31

We have previously observed in vitro that some stromal proteinases (MMP-2, MT1-MMP) were expressed or activated by invasive carcinoma cell lines exhibiting mesenchymal features, presumably acquired through an epithelial to mesenchymal transition (EMT). To examine the potential contribution of c-ets-1 to this phenotype, we have compared here the expression of c-ets-1 with invasiveness in vitro and expression of vimentin, E-cadherin, uPA, MMP-1 and MMP-3 in a panel of human breast cancer cell lines. Our results clearly demonstrate an association between c-ets-1 expression and the invasive, EMT-derived phenotype, which is typified by the expression of vimentin and the lack of E-cadherin. While absent from the two non-invasive, vimentin-negative cell lines, c-ets-1 was abundantly expressed in all the four vimentin-positive lines. However, we could not find a clear quantitative or qualitative relationship between the expression of c-ets-1 and the three proteinases known to be regulated by c-ets-1, except that when they were expressed, it was only in the invasive c-ets-1-positive lines. UPA mRNAs were found in three of the four vimentin-positive lines, MMP-1 in two of the four, and MMP-3 could not be detected in any of the cell lines. Intriguingly, MDA-MB-435 cells, which exhibit the highest metastatic potential of these cell lines in nude mice, expressed vimentin and c-ets-1, but lacked expression of these three proteinases, at least under the culture conditions employed. Taken together, our results show that c-ets-1 expression is associated with an invasive, EMT-derived phenotype in breast cancer cells, although it is apparently not sufficient to ensure the expression of uPA, MMP-1 or MMP-3, in the vimentin-positive cells. Such proteases regulation is undoubtedly qualified by the cellular context. This study therefore advances our understanding of the molecular regulation of invasiveness in EMT-associated carcinoma progression, and suggests that c-ets-1 may contribute to the invasive phenotype in carcinoma cells.
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PMID:Expression of c-ets-1 mRNA is associated with an invasive, EMT-derived phenotype in breast carcinoma cell lines. 924 54


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