Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P00750 (PLA)
 16,800 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The C3H/10T 1/2 embryo cell line, which is nontumorigenic when inoculated subcutaneously in saline suspension, produces tumors when implanted subcutaneously attached to 1 X 5 X 10 mm plastic plates. Under these in vivo conditions there is direct selection for "spontaneous" transformants that have undergone the specific cellular alterations required for neoplastic behavior. This is in contrast to the conventional situation where transformants are obtained in vitro and are only secondarily tested in vivo for neoplastic behavior. Early passages of cell lines from four different C3H/10T 1/2 tumors explanted back in culture were quantitatively examined for tumorigenicity and for alteration in the properties of density inhibition, anchorage dependence, serum requirement, and plasminogen activator production. A fairly consistent quantitative relationship was found between the degree of growth aggressiveness in vivo and the degree of expression of these phenotypic markers of the transformed state in vitro during early passages of the cell lines after tumor explantation.
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PMID:Neoplasms produced from C3H/10T 1/2 cells attached to plastic plates; saturation density, anchorage dependence and serum requirement of in vitro lines correlated with growth aggressiveness in vivo. 65 20

The distributions of urokinase and tissue plasminogen activators (uPA, tPA), uPA receptor (uPAR), and plasminogen activator inhibitors (PAI-1, PAI-2) were studied immunohistochemically in two subsets of colorectal adenocarcinomas with low and high aggressiveness, respectively: nine Dukes' stage A tumors with additional other good prognostic markers and 13 Duke's stage C tumors with also other poor prognostic markers (referred to as Dukes' stage A and Dukes' stage C tumors). The results showed that these components of the tissue destructive plasminogen activation system were accumulated at the invading front of the tumors. Both tumor groups showed accumulations of uPA, uPAR, and PAI-1 at the tumor-host interface compared with the location within the tumor epithelium and the adjacent normal mucosa and muscularis propria (all P < .05). However, the uPA level at the tumor-host interface in the Dukes' stage C tumors was twice the level in the Dukes' stage A tumors (P < .05). The uPAR level was also significantly higher in the Dukes' stage C tumors (P < .05), whereas the PAI-1 level was not significantly higher. This may indicate that uPA in more aggressive tumors exceeds the inhibitory capacity represented by PAIs, resulting in enhanced tissue destructive potential that promotes tumor invasion. uPA and uPAR antigen levels and the uPA/PAI-1 ratio at the tumor-host interface appeared to be related to tumor aggressiveness in colorectal cancer.
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PMID:Antigen levels of urokinase plasminogen activator and its receptor at the tumor-host interface of colorectal adenocarcinomas are related to tumor aggressiveness. 755 47

In an attempt to define the role of plasminogen activator in invasiveness and differentiation of human melanoma cells, the modulation of these parameters was studied in two melanoma clones characterized by marked differences in their basal features, using 12-O-tetradecanoyl-phorbol-13-acetate (TPA) and retinoic acid, two differentiation inducers, and doxorubicin, a cytotoxic agent. TPA induced only slight reductions, whereas retinoic acid and doxorubicin caused an increase in invasiveness, enzymatic activity and differentiation in the clone showing low invasivity, low urokinase-type plasminogen activator levels and high differentiation. In contrast, in the clone showing high invasivity, high urokinase-type plasminogen activator levels and low differentiation it was found that: TPA was ineffective; retinoic acid induced a reduction of plasminogen activator but no modifications of invasiveness and differentiation; doxorubicin caused a decrease in invasiveness and plasminogen activator activity but no modification of morphological features. The different behaviour of the two clones thus could be related to the basal features of the clones. The results reported here indicate that in the presence of these drugs the associations between invasiveness and urokinase-type plasminogen activator activity and between invasiveness and differentiation are lost. Drug treatment therefore significantly affected the features of the clone characterized by low biological aggressiveness (high differentiation, low invasiveness), whereas the highly aggressive clone did not show a consistent response to drug treatment.
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PMID:Modification of invasion and differentiation in human melanoma cell clones. 795 Mar 60

Even with the new fibrin-specific plasminogen activators thrombolytic therapy remains burdened with numerous side effects, some of them being severe or even life threatening, therapists being horrified if in rare cases the patient dies from severe haemorrhage subsequent to thrombolysis. The incidence and severity of bleeding increase with increasing aggressiveness of the therapeutic regimen and with increasing time during which the thrombolytic state is maintained. Furthermore, side effects related either to the plasminogen activator used (allergic reactions and systemic fibrinogen breakdown e.g.) or related to the underlying disease (pulmonary embolism and reperfusion arrhythmias e.g.) have to be considered. In order not to let thrombolysis become a double-edged sword, the risks of thrombolytic therapy should carefully be weighted against the benefits before thrombolysis is commenced.
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PMID:[Undesirable side effects in thrombolytic therapy]. 833 26

Carcinogenesis in the human colon is associated with a marked increase of urokinase type plasminogen activator and a decrease of tissue type plasminogen activator. This study was performed to determine the concentrations of urokinase type plasminogen activator and tissue type plasminogen activator in normal tissue and carcinomas along the upper part of the gastrointestinal tract. Activity and antigen levels of both activators were determined in homogenates of endoscopically obtained biopsies from normal and carcinomatous tissues. Although the concentrations of tissue type plasminogen activator and urokinase type plasminogen activator in normal squamous epithelium of the oesophagus were low compared with those in columnar epithelium from the stomach, the urokinase type plasminogen activator/tissue type plasminogen activator antigen ratio of the different locations showed hardly any difference. Significant but heterogeneous increases were found in urokinase type plasminogen activator concentrations of biopsy specimens originating from carcinomas of both epithelial cell types. A decrease in tissue type plasminogen activator concentrations, as found in human colon carcinomas, could only be shown in carcinomas of columnar epithelium origin but not in squamous cell carcinomas of the oesophagus. The increase of urokinase type plasminogen activator and urokinase type plasminogen activator/tissue type plasminogen activator antigen ratio and the decrease of tissue type plasminogen activator in the carcinomas did not show a significant correlation with known prognostic determinants as differentiation grade, TNM classification, intestinal metaplasia, inflammation, and ulceration. The heterogeneous increase of urokinase type plasminogen activator in oesophageal and stomach carcinomas, together with the recently described association of urokinase type plasminogen activator in tissue extracts of breast carcinomas with aggressiveness and prognosis, may be relevance to prognostic studies, may be of relevance to prognostic studies in oesophageal and gastric cancer.
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PMID:Plasminogen activators in normal tissue and carcinomas of the human oesophagus and stomach. 843 57

Malignant transformation is associated with alterations in both cell-cell and cell-matrix interactions. The E2 and C5 clones, derived from the human colon adenocarcinoma LoVo cell line, show, respectively, low and high metastatic capacity as experimental xenografts in vivo. In this study, we have assessed the adhesion and spreading of E2 and C5 cells on basement membrane laminin, expression of the laminin receptor integrins alpha 6 beta 1 and alpha 6 beta 4 and expression of gelatinolytic and plasminogen-dependent activities. On days 5 and 7 after subcutaneous grafting to immunosuppressed newborn rats, well-differentiated E2 tumors displayed a polarized expression of these integrin subunits, with the exception of the beta 1 subunit which remained pericellular. In contrast, C5 tumors were unorganized and the three integrin subunits remained nonpolarized and pericellular. Flow cytometry results showed that the expression of alpha 6 beta 1 and alpha 1 beta 4 integrins was weaker in the highly metastatic C5 clone than in the E2 clone whereas laminin expression was not significantly different. Under-expression and pericellular localization of these integrin receptors in C5 cells as compared to E2 cells may explain the difference in their binding and spreading capacity on laminin, organization of peritumoral basement membrane and maintenance of a differentiated phenotype. Whereas similar levels of gelatinolytic and plasminogen activator activities have been detected in the culture supernatant of the two clones, histozymograms showed that plasminogen-dependent caseinolysis appeared earlier in sections of C5 and parental tumors than in those of E2 xenografts. These results suggest that enhanced aggressiveness of C5 tumors in vivo may be linked to both an impairment of basement membrane setting due to integrin underexpression and distribution and of proteolytic activities modulated by tumor/host interactions.
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PMID:Expression of the alpha 6, beta 1 and beta 4 integrin subunits, basement membrane organization and proteolytic capacities in low and high metastatic human colon carcinoma xenografts. 862 Dec 66

The plasminogen activating system plays a key role in the cascade of tumour-associated proteolysis leading to extracellular matrix degradation and stromal invasion. Changes in the expression of this system, consisting of urokinase- and tissue-type plasminogen activators (uPA and tPA, respectively), plasminogen activator inhibitors (PAI-1, PAI-2) and uPA receptor, have been associated with tumour aggressiveness in a variety of solid malignant tumours. This paper describes a study of squamous intraepithelial lesions (SILs, n=36), squamous cell carcinomas (SCCs, n=42), and normal mucosa (n=5) of the uterine cervix by in situ hybridization with (35)S-labelled RNA probes. uPA transcripts were absent from normal mucosa and non-invasive lesions, but present in atypical epithelial cells of all microinvasive carcinomas ( n=19) and in some of the more advanced invasive carcinomas (n=11). PAI-1 transcripts were found in stromal cells of most tissue samples with, however, significantly increased levels in invasive SCC compared with SIL, microinvasive SCC, and normal mucosa. uPA-positive invasive carcinomas often displayed additional PAI-1 expression by tumour cells. At variance with uPA, tPA transcripts were found in atypical epithelial cells of low- and high-grade SILs. In the majority of SCCs tested (27/29 cases), the HPV 16 E6/E7 oncogene and uPA transcription were correlated. uPA and PAI-1 expression indicates invasive growth when expressed by atypical epithelial cells of squamous cervical lesions. Moreover, the presence of uPA transcripts is indicative of early invasive growth. uPA and tPA seem to have different functions in the development of invasive properties in uterine cervical squamous epithelium.
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PMID:Urokinase gene expression indicates early invasive growth in squamous cell lesions of the uterine cervix. 1054 82

There is abundant evidence that the plasminogen activator (PA) system with its key components uPA (urokinase-type plasminogen activator), its cell surface receptor uPA-R (CD87) and its inhibitor PAI-1 plays a key role in tumour invasion and metastasis. Elevated levels of these factors in tumour tissue are associated with tumour aggressiveness and poor patient outcome. Animal models suggest that the PA system is not essential for fertility or survival under physiological conditions. Thus, it seems well suited as a therapeutic target for patients with solid malignant tumours. Novel therapy concepts targeting the uPA system are currently being explored. A variety of different synthetic uPA inhibitor classes have been developed over the last decades. First generation inhibitors displayed a low uPA inhibitory potency combined with broad specificity. More recently, structure based design, x-ray crystallographic screening or NMR based screening have revealed a large number of new, potent and selective uPA-inhibitors. A few modern compounds have shown promising results in preclinical testing and are now ready for Phase I clinical studies. Other therapeutic strategies such as antagonists of uPA/uPA-R interaction or gene therapeutic approaches to suppress the uPA-system are still being evaluated in in vitro and in vivo models. For clinical application, a combination therapy targeting more than one of the interacting proteolytic pathways may be required for effective antiproteolytic therapy. In addition, antiproteolytic agents may provide additive or synergistic treatment benefits if used in combination together with conventional therapeutics, in particular in those solid tumours for which potent conventional regimens already exist.
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PMID:Interference with the urokinase plasminogen activator system: a promising therapy concept for solid tumours. 1172 4

Proteolytic factors belonging t the plasminogen activator family (plasmin, u-PA, t-PA, u-PAR, PAI-1, and PAI-2), which usually are involved in blood clotting and degradation of blood clots, are also present in healthy and diseased tissue of the kidney, lung, liver, gastro-intestinal tract, breast, prostate, ovary, and brain. These factors are engaged in brain development, angiogenesis and vascular invasion, wound healing as well as in placenta development and embryogenesis. Plasminogen activators u-PA and t-PA, their inhibitors PAI-1 and PAI-2, and the u-PA-receptor (u-PAR, CD87) are often elevated in solid malignant tumour tissues compared to their normal counterparts. In breast cancer patients, an elevated tumour tissue extract antigen content of u-PA, PAI-1, and u-PAR is associated with increased tumour aggressiveness and poor prognosis; in contrary, an elevated content of t-PA and PAI-2 indicates a favourable prognosis. For clinical relevant determination of these proteolytic factors in tumour tissue extracts, only enzymo-immunometric tests (ELISA) are recommended. Enzymometric and enzymographic tests are actually conducted only in an experimental, preclinical context.
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PMID:[Tumor-associated prognostic factors of the plasminogen activator family: determination and clinical value of u-PA, t-PA, PAI-1, and PAI-2]. 1611 55

The plasminogen activator system is a complex system with multiple interactions and members participating in fibrinolysis, cell migration, angiogenesis, wound healing, embryogenesis, tumor cell dissemination, and metastasis in a variety of solid tumors. Increased levels of uPA and/or PAI-1 in primary tumor tissues of breast cancer patients correlate with tumor aggressiveness and poor clinical outcome. Patients with high tumor tissue antigen content of uPA and/or PAI-1 have a worse probability of disease-free and overall survival than patients with low levels of both of the biomarkers, serving as prognostic markers. The clinical utility of uPA and PAI-1 has been proven on the highest level of evidence (LOE-I). Next to being clinically useful prognostic factors allowing estimates of the course of disease in early breast cancer, uPA and PAI-1 may also serve as predictive factors predicting response to systemic therapy. Node-negative primary breast cancer patients with high uPA/PAI-1 levels benefit significantly from adjuvant chemotherapy. The aim of the ongoing NNBC-3 trial is to determine the benefits of a sequential anthracycline-docetaxel regimen in high-risk node-negative breast cancer patients compared to the current standard of anthracycline-based chemotherapy. At present, uPA and PAI-1 provide the unique opportunity to allow validated and clinically relevant risk assessment of breast cancer patients, over and above that provided by established risk factors. Therefore, in the evidence-based, annually updated AGO guidelines for breast cancer management, the German Working Group for Gynecological Oncology (AGO) has recommended both biomarkers as risk-group-classification markers for routine clinical decision making in node-negative breast cancer, next to established clinical and histomorphological factors.
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PMID:uPA and PAI-1 in breast cancer: review of their clinical utility and current validation in the prospective NNBC-3 trial. 1842 92


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