Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0017636 (glioblastoma)
 18,345 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The human U373 glioblastoma/astrocytoma cell line was found to constitutively produce and secrete a plasminogen activator and a plasminogen activator inhibitor. The plasminogen activator was identified as urokinase based on apparent molecular weight, immunoblotting with anti-urokinase antibodies, and Northern blotting with a human urokinase cDNA probe. The inhibitor secreted by U373 cells was found to be related to the PAI-1 molecule based on reactivity with anti-human PAI-1 antibodies, apparent molecular weight, and Northern blot analysis with a human PAI-1 cDNA probe. The expression of both urokinase and the PAI-1-like molecule by U373 cells could be modulated by phorbol myristate acetate or by inflammatory mediators such as interferon-gamma and interleukin-1. In the case of interleukin-1, the alpha form exhibited no detectable effect while the beta form not only elevated inhibitor levels, it also appeared to induce the production of tissue plasminogen activator. Thus, in these cells interleukin-1 beta induces alterations in PA and PAI expression and interleukin-1 alpha does not, even though the two forms are reported to utilize the same cellular receptor.
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PMID:Modulation of plasminogen activator and plasminogen activator inhibitor expression in the human U373 glioblastoma/astrocytoma cell line by inflammatory mediators. 172 61

Fresh brain-tumor samples were obtained at operation and analyzed for their content of tissue type plasminogen activator (tPA) using an activity assay (gel chromatography zymogram) and an enzyme-linked immunospecific assay. The specimens were taken from 23 glioblastomas, 35 metastatic tumors, 42 meningiomas, 16 low-grade gliomas, and seven acoustic neurinomas; seven specimens were from normal brain. A strong correlation was found between the results of the two assays (r = 0.77, p less than 0.0001). There was a threefold difference in the tPA content of the benign tumors as compared to malignant tumors (p = 0.0006), the latter having less tPA. Histologically benign meningiomas contained higher tPA than malignant meningiomas (p = 0.01); however, the difference between low-grade gliomas and high-grade gliomas was less evident. Overall regression analysis data have shown an inverse relationship between the tissue content in tPA and the presence and degree of tumor necrosis and peritumoral brain edema (p = 0.004 and p = 0.0004, respectively). This finding was most consistent in the glioblastoma group where the correlation coefficient values were r = 0.53 and r = -0.55, respectively. There was no significant correlation between the tissue tPA content and the age and sex, steroid use, or plasma tPA of the patients or the duration of symptoms. In summary, this is the first demonstration of tPA in a large series of human brain tumors and in normal brain. The differences observed have clear biological significance and, although the source of tPA in tumor tissue is still unknown, a relative reduction in tPA in tumor tissue may play an integral role in the development of tissue necrosis and tissue edema. The lack of tPA in tumor necrosis was not due to tissue destruction and cell death since urokinase was readily detectable in that tissue.
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PMID:Biological significance of tissue plasminogen activator content in brain tumors. 189 96

Recent studies have suggested important roles for certain proteases and protease inhibitors in the growth and development of the CNS. In the present studies, inhibitors of urokinase or thrombin in cultured neural cells and serum-free medium from the cells were identified by screening for components that formed sodium dodecyl sulfate-stable complexes with 125I-urokinase or 125I-thrombin. Rinsed glioblastoma possessed two components that complexed 125I-urokinase. One was type 1 plasminogen activator inhibitor (PAI-1), because the 125I-urokinase-containing complexes were immunoprecipitated with anti-PAI-1 antibodies. The other component formed complexes with 125I-urokinase that were not recognized by antibodies to PAI-1 or protease nexin-1 (PN-1). Its identity is unknown. In addition to these cell-bound components, the glioblastoma cells also secreted two inhibitors that formed complexes with 125I-urokinase; one was PAI-1, and the other was PN-1. The secreted PN-1 also formed complexes with 125I-thrombin. It was the only thrombin inhibitor detected in these studies. Human neuroblastoma cells did not contain components that formed detectable complexes with either 125I-urokinase or 125I-thrombin. However, human neuroblastoma cells did contain very low levels of PN-1 mRNA and PN-1 protein. Added PN-1 bound to the surface of both glioblastoma and neuroblastoma cells. This interaction accelerated the inhibition of thrombin by PN-1 and blocked the ability of PN-1 to form complexes with 125I-urokinase. Thus, cell-bound PN-1 was a specific thrombin inhibitor.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Inhibitors of urokinase and thrombin in cultured neural cells. 198 20

We have studied the regulation by glucocorticoids and dibutyryl cAMP of the amounts of urokinase-type plasminogen activator (u-PA), tissue-type plasminogen activator (t-PA) and a Mr approximately 54000 plasminogen activator inhibitor accumulated in serum-free conditioned culture fluid by a human fibrosarcoma, a human glioblastoma and a human melanoma cell line (HT-1080, UCT/gl-1 and Bowes). For the quantitation of u-PA and t-PA, we used sandwich-type ELISA with a combination of polyclonal and monoclonal antibodies. For an estimation of variations in the amount of the inhibitor, we used sodium dodecyl sulphate-polyacrylamide gel electrophoresis followed by Coomassie blue staining of conditioned culture fluid proteins, the inhibitor protein band being identified by its selective removal by passage of the conditioned culture fluids through a column with monoclonal antibodies against the inhibitor. The modulation of the 3 proteins by the hormonal agents varied greatly between the cell lines. The proteins were independently regulated, in the sense that the hormonal agents did not concomitantly change their levels in the direction expected either to increase or decrease total extracellular plasminogen activator activity. In conditioned culture fluids containing both t-PA and inhibitor, the two were present in the medium as a Mr approximately 120 000 complex. In contrast, no u-PA inhibitor complexes were found in conditioned culture fluid from any of the cell lines; this is likely to be due to the occurrence of u-PA in the culture fluid in the one-chain proenzyme form, which, unlike active u-PA, does not react with the inhibitor. These findings illustrate the complexity of the regulation of extracellular plasminogen activator activity, and imply that the presumed functional diversity of u-PA and t-PA may be related to their independent regulation.
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PMID:Hormonal regulation of extracellular plasminogen activators and Mr approximately 54,000 plasminogen activator inhibitor in human neoplastic cell lines, studied with monoclonal antibodies. 301 58

Transforming growth factor-beta 1 has been shown to suppress the urokinase activity in the glioblastoma cell line T-MG1 and the carcinoma cell line T-CAR1. The molecular mechanisms behind the decrease in the proteolyic activity is shown to be at least partly due to increased synthesis of plasminogen activator inhibitor type-1 and not by decreased synthesis of urokinase.
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PMID:Transforming growth factor-beta 1 is a potent inducer of plasminogen activator inhibitor type-1 in human glioblastoma and carcinoma cell lines. 326 61

In the human glioblastoma cell line, T-MG1, plasminogen activator activity (PA-activity) was demonstrated by using the chromogenic substrate S-2251. Using monoclonal antibodies against human urokinase type PA (u-PA) and human tissue type PA (t-PA), only u-PA activity was found in T-MG1 cell extracts. The u-PA activity in T-MG1 cells was suppressed in a dose-dependent manner by B-TGF and EGF after 24 hours of exposure to these growth factors. Twenty units of B-TGF caused a decrease in PA-activity of 80%, while 10 ng/ml EGF gave a decrease in PA-activity of 60%. The suppressive effects of B-TGF and EGF were observed after 2 hours and 4 hours of incubation, respectively and sustained for at least 24 hours. The effects of B-TGF and EGF were not antienzymatic, but rather mediated through regulatory mechanisms. In view of the capacity of invasive growth of gliomas and the potential role of PA in invasive growth, the suppression of PA-activity in gliomas by B-TGF and EGF may be of importance.
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PMID:Type beta transforming growth factor and epidermal growth factor suppress the plasminogen activator activity in a human glioblastoma cell line. 326 20

Monoclonal antibodies against a human plasminogen activator of M(r) approximately 52,000 (HPA52) were derived by immunization of mice with an impure preparation of the enzyme (urokinase), subsequent hybridization of spleen cells with NSI-Ag4/1 myeloma cells, and cloning of the hybridomas. Selection of mice for hybridization and screening of hybridomas were based solely on direct inhibition of an enzymatic assay of the plasminogen activator with the impure enzyme preparation. A cloned hybridoma produced IgG1 antibodies that bound to and inhibited the enzymatic activity of HPA52 irrespective of whether the HPA52 was derived from urokinase or from human glioblastoma cells, whereas there was no inhibition of or binding to a plasminogen activator of M(r) approximately 70,000 from human melanoma cells or a plasminogen activator of M(r) approximately 36,000 that is a degradation product of HPA52 and present in urokinase. Nor did the anti-HPA52 IgG1 inhibit a murine plasminogen activator of M(r) approximately 48,000 derived from sarcoma virus-transformed cells. By using affinity chromatography with columns of anti-HPA52 IgG1 bound to Sepharose, HPA52 was purified from urokinase to homogeneity as evaluated by NaDodSO(4)/polyacrylamide gel electrophoresis. This study demonstrates that inhibitory monoclonal antibodies against enzymes can be derived with the sole use of impure enzyme preparations and shows how such antibodies subsequently can be used for enzyme purification.
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PMID:Monoclonal antibody that specifically inhibits a human Mr 52,000 plasminogen-activating enzyme. 680 14

Incorporation of the serine protease active site reagent diisopropyl fluorophosphate (DFP) into a plasminogen activator with an Mr of approximately 52000 released from cultured human glioblastoma cells was strongly enhanced by incubation with plasmin. This observation led to the isolation of an inactive form of the enzyme from serum-free conditioned culture fluid by affinity chromatography on a column of a Sepharose-bound monoclonal antibody raised against urokinase. An 831-fold purification was obtained with a yield of 41%. The purified molecule was homogeneous as evaluated by polyacrylamide gel electrophoresis with sodium dodecyl sulfate (NaDodSO4), having one stainable band under nonreducing as well as reducing conditions with an Mr of approximately 52000. It was unable to activate plasminogen, but catalytic amounts of plasmin converted it into active enzyme. After NaDodSO4-polyacrylamide gel electrophoresis, the active enzyme showed one band under nonreducing conditions, but after reduction, two bands with Mr values of approximately 20000 and 32000 were observed. The active enzyme incorporated [3H]DFP into the approximately Mr 32000 band, while no incorporation was observed into the inactive form. These findings show that the Mr 52000 human plasminogen activator exists in a proenzyme form consisting of a single polypeptide chain that by proteolysis between half-cystine residues is converted into the active enzyme consisting of two chains with molecular weights of approximately 20000 and 32000, the active site being on the latter chain. The results are consistent with the active form of the enzyme being identical with the higher molecular weight form of urokinase, and together with recent observations that a murine plasminogen activator is released from sarcoma virus transformed cells as an inactive proenzyme, they suggest that zymogens to plasminogen activators are of more general occurrence.
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PMID:Purification of zymogen to plasminogen activator from human glioblastoma cells by affinity chromatography with monoclonal antibody. 689 Dec 64

Eighty three patients suffering from brain tumors have been treated by anticancer pellets containing 5-FU, urokinase, mitomycin and BUdR in dimethylsiloxan (Silastic) for three years. Constant and prolonged release of the chemicals from the anticancer pellet had already been proved in vitro. The amount of daily release were 1-3/1,000 of original volume. Tissue concentration of 5-FU was measured by bioassay system using staphylococcus 209 P strain with plate dilution method. In spite of the rapid disappearance of serum 5-FU, the local high accumulation of 5-FU was demonstrated in vivo. In rat neurogenic tumor, 1.104 microgram/g was detected on 60 days after the application of anticancer pellet containing 500 mg of 5-FU. The growth of tumor was also suppressed. The clinical study consists of 83 patients, 30 of glioblastoma, 19 of metastatic brain tumor, 13 of astrocytoma, 7 of oligodendroglioma, 4 of ependymoblastoma, 4 of malignant lymphoma and 6 of others. The median survival time of gliblastoma was prolonged to 71.5 weeks by the implantation of anticancer pellet from 40 weeks of control group. However, the median survival time of astrocytoma and metastatic brain tumor were 24 and 6 months, respectively, which have no significant difference from control groups. In the patients of metastatic brain tumor, the regrowth of metastatic foci in the brain was completely suppressed. However, most of them were succumbed from the original tumors. The concentration of 5-FU in several human tissue was measured in ten patients with different time intervals after the implantation of the anticancer pellet. Although they have different histologic patterns, the concentrations of 5-FU in human brain tumors were ranged from 0.05 to 0.67 microgram/g by 14 months after the implantation of the anticancer pellet. The adjacent cystic fluids also contain from 0.62 to 4.9 microgram/ml of 5-FU for two years. These results mean that they are keeping higher level of 5-FU than the tumoricidal level of 5-FU (0.056 microgram/g) for more than two years. On the other hand, no respective accumulation was demonstrated in other tissues. None of the patients showed any adverse reactions except a continuous slight fever up to 38 degrees C.
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PMID:[Treatment of brain tumors with anticancer pellet--experimental and clinical study (author's transl)]. 709 76

A survey of 56 normal and neoplastic tissues has shown that plasminogen activators were released by cultured human cells in several molecular weights and their susceptibility to inhibition by antibodies to the normal urinary enzyme, urokinase. Melanoma cells characteristically secreted plasminogen activators which were immunochemically distinct from urokinase and which migrated on sodium dodecyl sulfate-polyacrylamide gel electrophoresis as a prominent, closely spaced doublet with an apparent molecular weight of approximately 70,000 and a minor molecular weight component of approximately 60,000. Enzymes with similar characteristics have been observed in serum-free harvest fluids collected from other neoplastic tissue (a breast carcinoma, a glioblastoma, a malignant teratoma, a uterine sarcoma, and a carcinoma of the renal pelvis) and from normal tissue (8-week embryo fibroblasts, normal esophageal fibroblasts, and one culture of normal adult bladder epithelium). Plasminogen activators released by cells derived from most normal adult tissues, or from a 26-week-old embryo, and from other tumors of ectodermal or mesenchymal origin were inhibited by anti-urokinase antibody and showed a closely spaced doublet with a molecular weight of 60,000 as the most abundant molecular species with no evidence of the enzyme with a molecular weight of 70,000.
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PMID:Molecular species of plasminogen activators secreted by normal and neoplastic human cells. 719 17


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