Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.21.73 (urokinase-type plasminogen activator)
 10,685 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Basement membrane-degrading enzymes of two clonal sublines of the murine Lewis lung carcinoma with distinct patterns of organ-selective metastasis were analyzed. Subline M-27 is highly metastatic to the lung and does not form liver metastases, while subline H-59 is highly metastatic to lymph nodes and liver, but not to lung. Qualitative and quantitative differences in the enzymatic profiles were found. H-59 cells which were significantly more invasive in vitro in the Matrigel invasion assay were found by zymogram analysis to secrete high levels of a 72 kDa gelatinase, while M-27 cells produced low levels of this gelatinase and of a higher molecular weight species which migrated in the 107 kDa region. On the other hand, M-27 cells produced significantly higher levels of urokinase type plasminogen activator (uPA) as indicated by a fibrinolysis assay and by Western blot analysis. Northern blot assays revealed an increase of approx. 3-fold in mRNA for cathepsin B in tumor M-27 which was reflected in a quantitative difference in plasma membrane cathepsin B levels as detected by Western blot analysis. H-59 cells on the other hand expressed approx. 8.5-fold more mRNA for cathepsin L. The quantitative differences in the levels of basement membrane degrading proteinases released by these tumor cells suggest that invasion by these cells is differentially regulated--a possible factor in their distinct patterns of dissemination.
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PMID:Differences in the repertoires of basement membrane degrading enzymes in two carcinoma sublines with distinct patterns of site-selective metastasis. 131 14

NIH 3T3 cells transformed by different activated ras genes showed different patterns of protease gene expression, indicating the existence of least two pathways for NIH 3T3 transformation from mutated ras genes. In cells transformed by activated mammalian EJ-ras and chimeric EJ/vHa-ras, high constitutive levels of urokinase plasminogen activator (uPA) mRNA and/or phorbol-12-myristate-13-acetate (PMA) inducibility of the uPA mRNA was observed. However, PMA did not induce cathepsin L (CL) mRNA levels in these same cell lines. In contrast, NIH 3T3 cells transformed by homologous yeast RAS1Leu sequences showed low levels of uPA mRNA and a lack of PMA inducibility of uPA mRNA, but did show high constitutive levels of the mRNA for CL and/or PMA inducibility of CL mRNA expression. Based on their differences in PMA inducibility these two phenotypes are designated rasuPA+/CL- and rasCL+/uPA-, respectively. Run-on assays indicated the differences in the levels of CL and uPA mRNA with ras transformation and phorbol ester induction are due to changes in transcription rates. Based on the observation of the two ras-transformed phenotypes for protease expressions, we asked whether uPA and CL can substitute for each other in the promotion of experimental metastasis. Injection of in vitro antisense inhibited cells in nude mice showed an inhibition of lung colonization by anti-uPA only in the rasuPA+/CL- phenotype and by anti-CL only in the rasCL+/uPA- phenotype. The data thus show the existence of two distinct activated ras-transformed metastatic phenotypes induced in the same parental cell line and that uPA or CL protease expressions alternatively facilitate the metastasis of cells with one ras phenotype and not with the other.
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PMID:Fibroblasts transformed by different ras oncogenes show dissimilar patterns of protease gene expression and regulation. 142 14

Increased levels of both the cysteine protease, cathepsin L, and the serine protease, uPA (urokinase-type plasminogen activator), are present in solid tumors and are correlated with malignancy. uPA is released by tumor cells as an inactive single-chain proenzyme (pro-uPA) which has to be activated by proteolytic cleavage. We analyzed in detail the action of the cysteine protease, cathepsin L, on recombinant human pro-uPA. Enzymatic assays, SDS-PAGE and Western blot analysis revealed that cathepsin L is a potent activator of pro-uPA. As determined by N-terminal amino acid sequence analysis, activation of pro-uPA by cathepsin L is achieved by cleavage of the Lys158-Ile159 peptide bond, a common activation site of serine proteases such as plasmin and kallikrein. Similar to cathepsin B (Kobayashi et al., J. Biol. Chem. (1991) 266, 5147-5152) cleavage of pro-uPA by cathepsin L was most effective at acidic pH (molar ratio of cathepsin L to pro-uPA of 1:2,000). Nevertheless, even at pH 7.0, pro-uPA was activated by cathepsin L, although a 10-fold higher concentration of cathepsin L was required. As tumor cells may produce both pro-uPA and cathepsin L, implications for the activation of tumor cell-derived pro-uPA by cathepsin L may be considered. Different pathways of activation of pro-uPA in tumor tissues may coexist: (i) autocatalytic intrinsic activation of pro-uPA; (ii) activation by serine proteases (plasmin, kallikrein, Factor XIIa); and (iii) activation by cysteine proteases (cathepsin B and L).
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PMID:Effective activation of the proenzyme form of the urokinase-type plasminogen activator (pro-uPA) by the cysteine protease cathepsin L. 155 16

Human lung macrophages express all four of the known lysosomal thiol proteases: cathepsins B, H, L, and S. These enzymes share a similar size and targeting mechanism for lysosomal accumulation and all have relatively indiscriminate substrate specificity in comparison with such highly selective serine proteases as urokinase or thrombin. These enzymes do have distinctive properties: only cathepsin B has C-terminal dipeptidase activity, only cathepsin H has potent aminopeptidase activity, and only cathepsin L and S are elastolytic. Cathepsin S is unique in that it is stable at neutral pH; indeed, at neutral pH it has elastolytic activity roughly comparable with that of neutrophil elastase. Recent studies of the differential expression of these cathepsins suggest they not only cooperate in terminal degradation of endocytized protein but also have specific functions such as proenzyme activation, antigen processing, and tissue remodeling, especially bone matrix resorption. Lysates of lung macrophages degrade elastin at neutral pH, suggesting that necrosis of macrophages at sites of macrophage accumulation, e.g., caseation necrosis, could contribute to tissue destruction. Tissue destruction and remodeling by thiol proteases expressed by live macrophages, however, is limited by tight compartmentalization of cathepsins to lysosomes. Nonetheless, macrophages accumulate at sites of known injury in cigarette smokers. Because these cells contain potent elastases, and because lysosomal enzyme release and cell surface acidification are regulated events, dysregulation of thiol protease expression in stimulated macrophages may contribute to the injury observed in cigarette smokers with non-alpha-1-protease inhibitor-type emphysema.
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PMID:The role of thiol proteases in tissue injury and remodeling. 795 52

We have established human oral-squamous-cancer cell lines, BHY and HN, derived from non-metastatic cancer and metastatic cancer respectively. We examined the expression of matrix-degrading enzymes and their inhibitors in these cell lines. Both cell lines expressed pro-matrix metalloproteinase (MMP)1, proMMP2, proMMP9, membrane-type MMP and urokinase-type plasminogen activator. In addition to these enzymes, BHY cells secreted proMMP7 and procathepsin L, while HN cells secreted a large amount of active MMP2. BHY cells secreted a tissue inhibitor of matrix metalloproteinase, TIMP2, but only a trace level of TIMP1. Contrary to BHY cells, HN cells secreted TIMP1, but only a trace level of TIMP2. When we inoculated these cells into the masseter muscle of nude mice, both types of cell formed solid tumors, whose microscopic appearance was identical to that of the original tumors. BHY tumors were highly differentiated squamous-cell carcinomas, and invasive to the masseter muscle and the mandibular bone. Despite their local aggressiveness, BHY tumors did not metastasize to any distant organs. HN tumors were poorly differentiated squamous-cell carcinomas, weakly invasive to the muscle, but not to the mandibular bone. However, HN tumors frequently metastasized to cervical lymph nodes. These results suggest that the net activity of MMP2 (active MMP2/TIMP2) and cathepsin L secreted from cancer cells may contribute respectively to lymph-node metastasis and to bone invasion by oral cancer cells.
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PMID:Possible contribution of active MMP2 to lymph-node metastasis and secreted cathepsin L to bone invasion of newly established human oral-squamous-cancer cell lines. 898

Invasive and metastatic cells require protease expression for migration through the extracellular matrix. Metastatic NIH 3T3 fibroblasts transformed by different activated ras genes showed two different protease phenotypes, rasuPA+/CL- and rasCL+/uPA- (Zhang, J-Y., and Schultz, R. M. (1992) Cancer Research 52, 6682-6689). Phenotype rasuPA+/CL- is dependent on expression of the serine-type protease urokinase plasminogen activator (uPA) and the phenotype rasCL+/uPA- on the cystine-type protease cathepsin L (CL) for lung colonization in experimental metastasis. The existence of multiple invasive phenotypes on ras-isoform transformation implied the activation of alternative pathways downstream from Ras. We now show that c-Raf-1, extracellular signal-regulated protein kinase (ERK)-1, and ERK-2 are hyperphosphorylated, and the ERK activity is high in both the uPA- and CL-dependent ras-transformed invasive phenotypes. Levels of c-Jun and c-Jun NH2-terminal kinase (JNK) activity are also high in the uPA-dependent phenotype, but they are almost undetectable in the CL-dependent phenotype. The uPA Ras-response element is a PEA3/URTF element, and mobility shift assays show a strong PEA3/URTF protein band in the uPA-dependent phenotype. This band is competed by a consensus AP-1 DNA sequence and by antibodies to PEA3 and c-Jun. Thus, the uPA-invasive phenotype appears to require the activation of Ets/PEA3 and c-Jun transcription factors activated by the ERK and JNK pathways, while the CL-invasive phenotype appears to require ERK activity with suppression of JNK and c-Jun activities. These postulates are supported by the introduction of a dominant negative c-Jun, TAM67, into cells of phenotype rasuPA+/CL-, which down-regulated the high uPA mRNA levels characteristic of this phenotype to basal levels and up-regulated basal levels of CL mRNA to levels similar to those observed in cells of phenotype rasCL+/uPA-. We conclude that the JNK pathway acts as a switch between two distinct protease phenotypes that are redundant in their abilities to grow tumors and metastasize.
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PMID:Characterization of downstream Ras signals that induce alternative protease-dependent invasive phenotypes. 903 12

Activation of protein kinase C- (PKC) and Fos/Jun-dependent signal transduction pathways are thought to be major effects of oncogene action in different tumor systems including human non-small-cell lung carcinoma (NSCLC). We have previously shown that the phorbol ester analogue phorbol-myristate-acetate (PMA), which is a potent activator of PKC, can induce squamous-type cellular differentiation and the expression of proteinases, such as plasminogen activators and pro-cathepsin L, in several NSCLC cell lines. To investigate the PMA-dependent effect on proteinase secretion in more detail, we have now analysed the role of a downstream transmitter of PKC activity in this process, namely Fos, which is part of the AP-1 transcription factor in the nucleus. We transfected a cell line derived from an undifferentiated squamous-cell lung carcinoma with different chimeric fos-estrogen receptor constructs (fos-ER) which makes selective activation of this transcription factor possible. The resulting clones were treated either with PMA as activator of PKC, or with diethylstilbestrol (DES), an estrogen analogue binding to and thereby activating preformed Fos-ER molecules. We show that cells treated with either substance undergo similar phenotypic changes (change from cuboidal to spindle-cell type) and decrease their doubling rates and cloning efficiencies. This is paralleled by the induction of several proteinase genes such as t-PA, urokinase, and pro-cathepsins B and L. Contrary to activated PKC, Fos in this system seems to be unable to initiate terminal squamous-cell differentiation, as assessed by the production of cornified envelopes. It is, however, efficient in the stimulation of neutral or lysosomal proteinase secretion as determined by Western-blot analysis and zymography. This Fos-ER expressing system thus seems to be a valuable tool in the molecular dissection of pathways that lead to the activation and secretion of proteinases in NSCLC cells.
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PMID:Control of proteinase expression by phorbol-ester- and Fos-dependent pathways in human non-small-cell lung-cancer cells. 913 54

Proteases such as matrix metalloproteinases (MMPs), cysteine- and serine-proteinases are capable of degrading extracellular matrix and basement membranes and have been implicated in human brain tumours. MMPs are a homologous family of zinc-dependent proteases. Within this group, attention has been focused on the gelatinases (MMP-2 and MMP-9) which are thought to play an important role in tumour progression. The cysteine proteinases which have received most attention in relation to tumour progression are cathepsin B (CB) and to a lesser extent cathepsin L (CL). Among the serine proteinases, urokinase plasminogen activator and its receptor have been the subject of much investigation. In the present review, evidence from current literature on the possible role or significance of serine- and cysteine-proteinases and MMPs and their inhibitors in human brain tumours is discussed with special reference to gliomas. Although direct evidence is reported for MMPs and serine proteinases to support their role in glioma invasion, much of the evidence for the involvement of cysteine proteinases remains circumstantial.
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PMID:Proteases and their inhibitors in human brain tumours: a review. 942 49

The biochemical mechanism(s) by which germ cells can form specialized junctions with Sertoli cells in the seminiferous epithelium at various stages of the spermatogenic cycle is unknown. This study sought to examine the biochemical changes that are involved when germ cells are cocultured with Sertoli cells in vitro preceding the establishment of specialized Sertoli-germ cell junctions. While isolated germ cells were allowed to attach to Sertoli cells, media from both the apical and basal compartments of bicameral units were collected to assess serine and cysteine protease activity. The expression of selected serine and cysteine proteases and their corresponding inhibitors in these Sertoli-germ cell cocultures was also examined by RT-PCR. Using an [125I]-collagen film assay, a transient but significant increase in serine protease activity was noted in both the apical and basal compartments when germ cells began to settle onto the Sertoli cell monolayer preceding the formation of intercellular junctions. A specific tryptase (RNK-Tryp 2, a serine protease formerly cloned from a rat granular lymphocyte leukemia cell line, RNK-16, cDNA expression library) was shown to be expressed exclusively by Sertoli cells and not germ cells. Furthermore, Sertoli cell tryptase expression as well as urokinase plasminogen activator (u-PA, also a serine protease) increased significantly when germ cells were adhering to Sertoli cells. The decline in total serine protease activity when Sertoli-germ cell junctions were being formed was accompanied by a concomitant increase in alpha2-macroglobulin (alpha2-MG, a nonspecific protease inhibitor) expression. No significant changes in cysteine protease activity in either the apical or basal compartment were noted. However, there was a transient but significant increase in cathepsin L expression when germ cells were adhering to Sertoli cells preceding cell junction formation. The subsequent reduction in cathepsin L expression after this transient increase was accompanied by a concomitant increase in cystatin C expression. These results suggest that proteases and their corresponding inhibitors are working synergistically and are likely to be involved in the adherence of germ cells to Sertoli cells and the subsequent formation of intercellular junctions.
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PMID:Interactions of proteases and protease inhibitors in Sertoli-germ cell cocultures preceding the formation of specialized Sertoli-germ cell junctions in vitro. 943 34

In node-negative breast cancer, 70% of patients are cured by surgery alone and thus should be spared the necessity of systemic adjuvant treatment. Histomorphological and tumor biological prognostic factors may be employed to assess the patient's risk profile with regard to disease recurrence and death. To evaluate the relationship between tumor biological factors and the metastatic potential of primary breast cancer, proteolytic factors uPA, PAI-1, and cathepsin L, which are associated with tumor invasion and metastasis, were determined in breast cancer tissue extracts by ELISA and the values assessed by uni- and multivariate analysis as well as CART (classification and regression trees) in comparison with traditional prognostic factors. Cysteine protease cathepsin L, serine protease uPA, and the protease inhibitor PAI-1 were determined by ELISA in extracts of primary tumors of 103 node-negative breast cancer patients and values assessed by univariate and multivariate analysis in comparison with traditional prognostic factors (tumor size, steroid hormone receptor status, grading, vessel invasion, menopausal status). Median follow-up of patients still alive at time of follow-up was 56.5 months (range 34-88). PAI-1, cathepsin L, tumor size, grading, and steroid hormone receptor status but not uPA, vessel invasion, and menopausal status were of prognostic relevance for disease-free survival (univariate analysis). Multivariate analysis of disease-free survival (Cox proportional hazards model) disclosed PAI-1 (relative risk of 8.6, p = 0.0001) to be the only strong and statistically independent prognostic factor. By CART-analysis, however, the combination of PAI-1 (< or = 14 ng/mg protein) and cathepsin L (< or = 1,100 ng/mg protein) allowed the identification of a subgroup comprising 68% of the node-negative breast cancer patients having a very low risk of disease recurrence (2/70; incidence of 0.8% per year) versus the high-risk group with PAI-1 (> 14 ng/mg protein) and cathepsin L (> 1,100 ng/mg protein) showing an increased recurrence rate (14/33; incidence of 8.6% per year). We conclude that by the combined determination of PAI-1 and cathepsin L tumor levels low-risk node-negative breast cancer patients may be identified. These patients most probably will not benefit from systemic adjuvant therapy.
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PMID:Identification of low-risk node-negative breast cancer patients by tumor biological factors PAI-1 and cathepsin L. 970 80


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