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

The fibrinolytic characteristics of the endothelial hybrid cell line EA.hy 926, established by fusing a human umbilical vein endothelial cell with a human carcinoma cell line, were studied. The hybrid cell line produced large amounts of tissue-type plasminogen activator (t-PA), plasminogen activator inhibitor type 1, and a small amount of urokinase. All plasminogen activator present in conditioned medium was complexed with inhibitor because the cells secreted plasminogen activator inhibitor in excess over plasminogen activator and no activator activity was detectable in conditioned media by direct activity assays. t-PA activator activity was, however, demonstrable in conditioned media after treatment with sodium dodecyl sulfate, in agreement with t-PA antigen determinations. Increased plasminogen activator inhibitor activity could be induced by incubating the cells in the presence of endotoxin or microtubule inhibitors, whereas increased t-PA activity could be induced by microtubule inhibitors. Interleukin-1 had no effect. The fibrinolytic characteristics of the hybrid cell line were stable for at least 30 passages. The perpetual human hybrid cell line EA.hy 926 therefore may be a useful tool for the study of fibrinolysis in cultured endothelial cells.
 ...
PMID:Fibrinolytic properties of a human endothelial hybrid cell line (Ea.hy 926). 313 Sep 8

Plasma concentrations of urokinase-type plasminogen activator (competitive radioimmunoassay), tissue-type plasminogen activator (sandwich enzyme-linked immunosorbent assay), and plasminogen activator inhibitor (functional assay) were measured in 17 women with endometrial cancer and 52 women with cervical carcinoma. Significantly increased plasma urokinase-type plasminogen activator antigen levels were found (11.3 +/- 4.7 ng/mL) in cervical cancer patients when compared with an age-matched control group (7.4 +/- 0.6 ng/mL). Women with endometrial cancer (9.9 +/- 2.0 ng/mL) showed a similar pattern of plasma urokinase-type plasminogen activator antigen levels. Patients with advanced cervical cancer (International Federation of Gynecology and Obstetrics stages III and IV) revealed higher plasma urokinase-type plasminogen activator antigen levels than those with stages I and II disease. Compared with an age-matched control group, neither carcinoma group showed elevated plasma concentrations of tissue-type plasminogen activator and plasminogen activator inhibitor.
 ...
PMID:Increased plasma levels of urokinase-type plasminogen activator with endometrial and cervical cancer. 313 31

The correlation between malignant transformation and increased PA synthesis or secretion has been examined in a variety of cell lines. To study the relationship between content and composition of PAs and colorectal neoplasms, we measured u-PA and t-PA antigen levels in normal mucosa, tubular adenoma, adenocarcinoma in adenoma, and adenocarcinoma, using a sensitive sandwich enzyme immunoassay. This assay was very sensitive and was not hindered by the presence of serine protease inhibitors. Both adenomas and carcinomas had higher u-PA antigen levels than normal mucosa. The u-PA antigen level of adenomas was lower than that of carcinomas. Antigen level of t-PA, however, was lower in both adenomas and carcinomas compared with that in normal mucosa, the values being lowest in carcinomas. Two cases of carcinoma in adenoma had PA contents similar to those of carcinomas. u-PA antigen level of adenomas with dysplastic epithelium was higher than that of adenomas without dysplastic epithelium. Therefore, the increase of u-PA content in adenomas could be a parameter of malignant changes in adenomas.
 ...
PMID:Comparative study of plasminogen activator antigens in colonic carcinomas and adenomas. 317 33

Colon carcinoma cells are first found as microscopic foci within benign tumors or adenomas. The carcinoma must invade the adenoma which protrudes into the colon lumen before it can infiltrate the bowel wall. A quantitative model for this process has been developed in tissue culture in which human colon carcinoma cells destroy cocultivated adenoma colonies. 43 adenoma colonies were assayed by cocultivation with carcinoma cells. Constitutive secretion of the urokinase form of plasminogen activator by carcinoma cells apparently plays some role in adenoma destruction as inhibition of this protease by the competitive inhibitor benzamidine reversibly inhibited adenoma destruction (p less than 0.01). Elevation of plasminogen activator secretion by addition of the tumor promoter 12-tetradecanoylphorbol-13-acetate significantly enhanced the destruction of colonies cultured from tubular adenomas with only mild dysplasia (p less than 0.025) and from villous, villotubular and tubular adenomas with moderate to severe dysplasia (p less than 0.0005).
 ...
PMID:Tumor-promoter-enhanced destruction of noninvasive human benign colon tumor cells by cocultivated carcinoma cells. 323 26

Cell lines derived from 3 different types of human tumor (e.g., squamous carcinomas, melanomas and gliomas) were examined for production of plasminogen activator activity and for attachment and spreading on various extracellular matrix components in the presence or absence of plasminogen. All of the squamous carcinoma and melanoma lines produced high levels of plasminogen activator activity. In contrast, 4 of 6 glioma lines had undetectable activity. Cells from all 3 tumor types attached and spread on fibrinogen-coated or fibrin-coated plastic dishes in the absence of plasminogen. In the presence of exogenous plasminogen, the attachment and spreading of the cells which produced high levels of plasminogen activator activity was inhibited. The plasminogen activator-deficient cells were much less sensitive to exogenous plasminogen. In the presence of plasminogen, attachment and spreading on fibronectin-coated dishes was also partially inhibited. In contrast, plasminogen had no effect on the attachment and spreading of the cells on type-I or -IV collagen, laminin or thrombospondin. Previous studies have shown that tumor-cell adhesion to the extracellular matrix depends on the synthesis of receptors for extracellular matrix components or on the synthesis of extracellular matrix components themselves. The present study shows that, in addition, the production of enzymes which are capable of degrading these components also influences tumor-cell adhesion to extracellular matrix moieties.
 ...
PMID:Plasminogen activator production by human tumor cells: effect on tumor cell-extracellular matrix interactions. 369 23

Hypofibrinogenemia and disseminated intravascular coagulation are common events in patients with metastatic prostate carcinoma. This study tests the hypothesis that prostate tumor growth and metastasis is associated with sustained activation of fibrinolysis secondary to increased release of plasminogen activator. We implanted an androgen-insensitive prostate tumor into an inbred strain of rats and serially measured plasminogen, plasminogen activator, plasmin and fibrinogen. Control groups included animals without tumor and a group implanted with transitional cell bladder carcinoma, a locally infiltrating tumor not usually associated with hemostatic complications. Our results showed a significant and steady rise in plasma plasminogen activator, plasmin and fibrinogen levels in animals implanted with prostate cancer. This, however, is not specific for prostate tumor. Similar, perhaps more profound changes were noted in animals implanted with the transitional cell carcinoma.
 ...
PMID:The fibrinolytic system in experimental prostate tumor. 381 May 52

Human carcinoma HEp-3 lost its tumorigenic and metastatic potential upon prolonged culture in vitro. This change was accompanied by a reduced production of plasminogen activator (PA) of the urokinase type (uPA), which is secreted by HEp-3 cells, a change in response to effectors that modulate uPA production, and an alteration of cell morphology. Similar but more rapid changes occurred when malignant HEp-3 cells were exposed to dimethyl sulfoxide (DMSO). uPA activity in the culture medium dropped below 50% of the control level within 6 h after the addition of DMSO and became undetectable after 24 h of treatment. This drop in uPA activity was not caused by an increased production of PA inhibitors. The cell-associated uPA decreased to 25 to 30% of the control level within 6 h of DMSO treatment and remained at this level for at least 96 h; the reduced uPA production was partially accounted for by a rapid decrease in the functional and chemical concentration of uPA mRNA. In contrast, the concentrations of most of the abundant mRNA species did not appear to be significantly affected, and cell growth was only slightly inhibited in the presence of DMSO. Malignant HEp-3 cells treated with DMSO responded to cholera toxin with an enhanced production of uPA, and their morphology became indistinguishable from that of nonmalignant HEp-3 cells grown in vitro for prolonged periods of time. All of the above changes were fully and rapidly reversible. The inhibitory effect of DMSO on PA production appears to be specific for uPA of human cell lines.
 ...
PMID:Effect of dimethyl sulfoxide on human carcinoma cells, inhibition of plasminogen activator synthesis, change in cell morphology, and alteration of response to cholera toxin. 383 48

The tissue levels of two proteolytic enzymes, plasminogen activator and cathepsin B - like cysteine proteinase, which were found to be increased in malignant tumors and to be proportional to tumor metastatic potential in some instances, have been determined in a panel of solid metastasizing tumors in mice. The examination of B16 melanoma, MCa mammary carcinoma and of two lines of Lewis lung carcinoma with widely different potential to spontaneously metastasize, showed no correlation between metastatic potential and the tissue content of the proteinases considered. The treatment of the animals with cytotoxic antitumor drugs (CCNU, GANU, cisplatin, and cyclophosphamide) or with antimetastatic drugs acting with a mechanism unrelated with cytotoxicity (ICRF 159 and DM-COOK) caused only marginal inhibition in some instances, whereas no meaningful pattern of inhibition either based in terms of metastatic potential of the tumor or on drug mechanism of action was recognizable. A direct involvement of the two proteinases examined in the process of metastasis in the tumor panel used is thus not apparent, although a more complex interaction with other latent proteinases and inhibitors might be operative.
 ...
PMID:Proteinases and proteinase inhibition by cytotoxic and antimetastatic drugs in transplantable solid metastasizing tumors in mice. 389 94

Eighteen patients with renal-cell carcinoma have been investigated in an attempt to elucidate the ratio of active urokinase enzyme to urokinase antigen in the tumor and adjacent normal kidney. The tumor itself exhibited a significantly increased total fibrinolytic activity, an increase in the relative contribution of anti-urokinase IgG-inhibitable plasminogen activator activity and increased levels of urokinase antigen when compared to normal renal tissue. In tumor-adjacent tissue total fibrinolytic activity was also, but not significantly, increased, this increase being completely due to tissue-type plasminogen activator. Correlation of active urokinase-type plasminogen activator with urokinase antigen revealed that in tumor tissue the enzyme was present to more than 70% in its active form whereas in tumor-adjacent tissue and normal renal tissue only half of the enzyme appeared to be active. No correlation was obtained between urokinase antigen present in one of the 3 tissues investigated and plasma urokinase antigen.
 ...
PMID:Increased urokinase activity to antigen ratio in human renal-cell carcinoma. 392 43

The fibrinolytic system was studied in primary biliary cirrhosis (16 patients) and large bile duct obstruction (10 patients, nine of whom had carcinoma). Plasma fibrinolysis (plasminogen activator activity) was decreased and fibrinogen increased in both groups of patients, particularly in those with large duct obstruction. These changes were related to the degree of cholestasis. Plasminogen activator activity was inversely related to serum triglyceride levels in patients with primary biliary cirrhosis. Urokinase inhibitors were decreased in both groups and antiplasmins increased in patients with large duct obstruction; fibrin/fibrinogen degradation products were normal in primary biliary cirrhosis and moderately increased in large duct obstruction. None of these fibrinolytic indices was related to the degree of cholestasis. Fibrinolytic activity and fibrinogen returned almost to normal levels after palliative surgery in the three patients with large duct obstruction who were studied. The decreased plasma fibrinolysis and increased fibrinogen may be due to altered lipid metabolism in cholestatic jaundice. In patients undergoing surgery for large duct obstruction there may be an increased risk of thrombosis.
 ...
PMID:Fibrinolysis in cholestatic jaundice. 412 Aug 48


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>