Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0023418 (leukemia)
 93,477 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The plasminogen activator levels of a series of murine tumors commonly used in cancer drug screening were determined and compared to the levels found in normal mouse tissues. Tumors high in plasminogen activator included the B16 and colon 26. The Lewis lung and M5076 carcinoma showed an intermediate level of activity, while the plasminogen activator activity in the L1210 leukemia and colon 38 was barely elevated above background. The specific activity of the enzyme (per micrograms protein) in extracts of B16 and colon 26 was three or four times higher than in the most active normal organs surveyed (kidney, lung, brain and intestine). The high level of plasminogen activator activity measured in extracts of the B16 tumor was reflected in a substantial elevation of the levels of fibrin degradation products in the serum of mice carrying this tumor. This result suggests that the tumor-associated plasminogen activator activity is less subject to inhibitory controls in vivo than is the plasminogen activator of most normal tissues, since the total mass of the tumor was far less than the total mass of the fibrinolytically active tissues, and yet the bulk of the fibrin degradation products were caused by the tumor. We conclude that the high levels of plasminogen activator activity which are observed in many human tumors are found only in some of the transplantable murine tumors. Since this enzyme is active at an increased level in vivo in mice carrying the B16 tumor, plasminogen activator may be a suitable target for selective, enzyme-activated chemotherapy with this tumor test system.
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PMID:Plasminogen activator in normal and tumor-bearing mice. 668 48

We have investigated the effects of the tumor promoter 12-0-tetradecanoyl-phorbol-13-acetate (TPA) on plasminogen activator production, hexose transport and metabolism, and the incorporation of choline into the acid soluble pool and into phosphatidylcholine in suspension cultures of mouse L, mouse P388 leukemia, human HeLa, and Chinese hamster ovary cells, and in monolayer cultures of baby hamster kidney (BHK), mouse 3T3, mouse 3T6, and mouse P388D1 macrophage-like cells. BHK, 3T3, P388D1, and P388 cells produced plasminogen activator constitutively, but no significant production was observed in the other cell lines. Plasminogen activator production was induced or stimulated by TPA only in P388 cells (10- to 20-fold by 100 ng TPA/ml). On the other hand, phosphatidylcholine synthesis was stimulated by TPA only in HeLa cells, and hexose transport, as measured with 3-0-methyl-D-glucose, only in 3T3 and P388D1 cells, as well as in human lymphocytes. The stimulation of hexose transport occurred more rapidly than the induction of plasminogen activator production and seemed to be part of the mitogenic response of cells to TPA treatment. A stimulation of deoxyglucose uptake was similarly limited to 3T3 and P388D1 cells. A significant decarboxylation of carbon 1 of deoxyglucose occurred in P388 and P388D1 cells, but not in Novikoff cells, and any decarboxylation that occurred was not stimulated by TPA. The results indicate that the various investigated responses of cells to TPA are unrelated and occur independent of each other. The time courses of the biochemical responses also differ significantly.
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PMID:Lack of correlation between effects of tumor promoter TPA on plasminogen activator production, phosphatidyl choline synthesis, and hexose transport in mammalian cell culture systems. 719 88

Haemostatic parameters were studied in 12 adult patients with acute myeloid leukaemia and acute lymphoblastic leukaemia in complete remission using high-dose cytosine arabinoside regiments together with with other drugs. Increased tissue plasminogen activator (t-PA:Ag) antigen 4 hours after AraC application (p < 0.05) as well as increased levels of plasminogen activator inhibitor activity (PAI) (p < 0.05) and fibrinopeptide A (FPA) antigen (p < 0.05) were observed on day 2. All patients during bone marrow aplasia suffered from infectious complications (7 from sepsis and 5 from fever of undetermined origin). During that period of infection the increased levels of FPA on day 21 (p < 0.05), PAI on days 15 and 21 (p < 0.05) and fibrinogen on day 21 (p < 0.05) as well as decreased values of antithrombin III (p < 0.05) on day 21 and protein C on day 15 (p < 0.05) were measured. t-PA:Ag, plasminogen, alpha 2 antiplasmin and fibrin(ogen) degradation products were within normal throughout infectious complications. None of the patients experienced clinically manifest thrombotic complication. Though the results demonstrate that changes found were not clinically important (even if they were statistically significant), and that haemostasis was compensated as well as that thrombosis was not serious problem, authors recommend routine haemostasis monitoring in acute leukaemia patients, especially at diagnosis, in association with chemotherapy and during infectious complications.
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PMID:[Hemostasis in patients with acute leukemia treated with high doses of cytosine-arabinoside: the effect of chemotherapy and infectious complications on hemostasis]. 781 98

Recent reports have suggested that basic fibroblast growth factor (bFGF) could play a permissive role in hematopoiesis, in combination with specific colony-stimulating factors. We investigated the expression of bFGF and FGF-receptors (FGF-Rs) in leukemic cell lines of various hematopoietic lineages. Three protein isoforms of bFGF of approximately 18, 22 and 24 kDa were detected in the myeloid cell line K562, but not in myelomonocytic or lymphoid (T or B) cell lines. In vitro-induced differentiation of K562 cells did not change the pattern of expression of the different bFGF isoforms. Accordingly, the mRNA of bFGF was found expressed in K562, but not in other leukemic lines tested, as assayed by reverse transcript amplification (RT-PCR). Using the same technique, we searched for the presence of high affinity FGF-Rs on these cells: in eight out of ten cell lines tested, mRNA for at least one FGF-R among FGF-R1, FGF-R3 or FGF-R4 was expressed, whereas FGF-R2 was never detected. We found that two cell lines were responsive to bFGF in different biological assays: (i) in K562 myeloid cells induced to differentiate by hemin, preincubation with bFGF and heparin increased cell viability and decreased hemin-induced DNA fragmentation, without affecting erythroid differentiation; and (ii) in U937 monocytic cells, the production of plasminogen activator was increased by bFGF or aFGF in combination with heparin. Binding experiments with 125I-bFGF (up to 200 pM) in the presence of heparin revealed high affinity receptors on the K562 and U937 cell lines (1177 +/- 440 and 392 +/- 184 sites/cell, Kd = 61.7 +/- 8.6 and 43.1 +/- 13.5 pM, respectively). Thus our results strongly suggest that cells of hematopoietic origin could express functional FGF-receptors.
Leukemia 1995 Jan
PMID:Expression of basic fibroblast growth factor (bFGF) and FGF-receptors in human leukemic cells. 784 32

In recent years, it is known that endothelial cells play an important role in the genesis of some diseases, but there are only few papers dealing with the role of endothelial cells in leukemia. In this study some of the active factors released by the endothelial cells in patients with acute leukemia such as von Willebrand factor, prostaglandin, fibronectin, tissue-type plasminogen activator and its inhibitor were determined. It was found that the levels of these factors changed significantly in patients with acute leukemia, as compared with those in normal controls, especially in cases with bleeding tendency and infection. The possible mechanism and the clinical significance were discussed.
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PMID:[Active factors released by endothelial cells in acute leukemia]. 804 83

Plasma interleukin-6 (IL-6) was higher in patients with disseminated intravascular coagulation (DIC) than in those without DIC. Levels of IL-1 beta and TNF alpha were also significantly higher in patients with DIC. Plasma IL-6 was highest in patients with underlying sepsis and was also high in those with advanced solid cancer. Levels were high in some patients with acute promyelocytic leukaemia and were significantly higher in patients with organ failure than in those without this complication. Plasma IL-6 was higher in DIC patients showing a poor response to therapy than in those with a good response. Incubation with IL-6 caused significant increases in tissue factor activity in mononuclear cells and release of plasminogen activator-1 antigen from human umbilical vein endothelial cells. As increases in IL-6 might give rise to hypercoagulable and hypofibrinolytic states, this may be a cause of DIC and be related to prognosis and organ failure.
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PMID:Increased plasma level of interleukin-6 in disseminated intravascular coagulation. 821 55

In patients with disseminated intravascular coagulation (DIC), hyperfibrinolysis was observed in patients with leukaemia, but hypofibrinolysis was seen in those with sepsis. Although the plasma tissue plasminogen activator (t-PA) level was higher in patients with DIC than in those without DIC, there was no significant difference in t-PA level between the patients with leukaemia and sepsis. Hyperfibrinolysis might not be caused by t-PA derived from leukaemic cells, although the PA antigen level in leukaemic cell homogenates was significantly higher in patients with DIC than in those without DIC. The activation of t-PA by leukaemic cell homogenates in the absence of bromocyan fibrinogen fragments suggested that leukaemic cell homogenates had t-PA stimulator activity. The t-PA stimulator activity was high in both acute myeloblastic leukaemia (AML) and acute lymphoblastic leukaemia (ALL), especially in DIC, but this activity was not detected in chronic myelocytic leukaemia (CML) or normal cells. Since fibrinogen and soluble fibrin monomer complex levels in leukaemic cells were also high in patients with DIC, fibrinogen degradation products might be the major t-PA stimulator in leukaemic cells. This might be one of the causes of hyperfibrinolysis in leukaemia.
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PMID:Stimulation of tissue type plasminogen activator by leukaemic cell homogenates. 821 56

We have examined the mononuclear cell fraction from 35 individuals, 18 with hematologic malignancies and 17 healthy controls for the presence of cell surface-associated plasminogen activator (PA) activity. PA activity was found on the cell surface of 10 out of 12 samples from patients with acute leukemia. In addition to active urokinase (uPA) found on the cell surface in four out of five acute myeloid leukemia patients, tissue-type PA activity was detected in the same samples (3 of 5). Two out of four samples from acute lymphoid leukemia displayed only uPA activity and three out of three samples from biphenotypic leukemia were also clearly uPA-positive. Plasmin activity was not detected in any of the samples. PA activity was not found on the surface of mononuclear cells from either patients with chronic lymphoid leukemia or healthy controls and, in this respect, the cell surface-bound uPA activity behaved as a marker for acute leukemia. The finding of PA activity on the cell surface in acute leukemia suggests that there may be continuous generation of plasmin with consequent consumption of plasma plasmin inhibitors.
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PMID:Abundant urokinase activity on the surface of mononuclear cells from blood and bone marrow of acute leukemia patients. 833 54

Disturbances in the regulation of the balance between the fibrinolytic and procoagulant properties of leukemic cells may contribute to the coagulopathy of acute leukemia. The coagulant response to a number of stimuli is regulated by the expression of tissue factor, but the role of the plasminogen activator inhibitors, PAI-1 and PAI-2, in contributing to the net coagulant response is not known. In this study, we have examined the production of these proteins by cultured myeloid leukemic cells arrested at different stages of differentiation. Northern blot analysis showed time-dependent and differential production of mRNA for PAI-2 and tissue factor, and to a much lesser extent, PAI-1, in response to the differentiating agent, 12-phorbol-13-myristate acetate. The capacity to synthesize PAI-2 appeared to be related to the stage of myeloid cell differentiation. Examination of the gene products by immunoblot analysis demonstrated multiple forms of PAI-2 in all myeloid cells examined. In addition, a common characteristic of all the myeloid cells was the production of a high molecular weight species of tissue factor which may be a secreted form unique to leukemic cells. Taken together, the findings demonstrate that myeloid leukemic cells are capable of generating a multicomponent coagulant response.
Leukemia 1993 Jun
PMID:Tissue factor and plasminogen activator inhibitor expression in the differentiation of myeloid leukemic cells. 830 77

The urinary type plasminogen activator, urokinase (uPA) is localized on the cell surface through the binding of a specific receptor, the uPA receptor (uPAR). The uPA localization enhances plasmin formation on the cell surface and facilitates cell migration. The cellular and tissue distribution of uPAR is not fully established. We have analyzed uPAR expression in nine leukemic cell lines of distinct lineages and maturational states and correlated this with expression of plasminogen receptors, tissue-type plasminogen activator (tPA) receptors and LDL receptor-related protein (LRP). The most immature and least differentiated cell line (an erythro-myeloid cell line) and cells of lymphoid lineage, did not express uPAR, whereas cells differentiated along the myelo-monocytic pathway displayed this receptor. Plasminogen and tPA receptors were expressed by all leukemic cell lines and by all nucleated peripheral blood cells but B and T lymphocytes were negative for cell surface expression of both uPAR and LRP while monocytes and neutrophils were positive for expression of both uPAR and LRP. PMA stimulation induced surface expression of uPAR in lymphocytes but did not induce expression of LRP by these cells. In contrast, lymphoid cell lines were negative for uPAR expression even after PMA stimulation, indicating differences in regulation of uPAR expression between lymphocytes and lymphoid cell lines. The pattern of uPAR expression on leukemic cell lines was also studied on bone marrow blast cells from leukemic patients. Only the most mature myeloid cells expressed uPAR on their surfaces. In contrast, M3 leukemic cells and other blast cells displaying lymphoid markers such as TdT (+) and/or CD2 (+) did not express intracellular or cell-surface associated uPAR, indicating an heterogeneity among these promyelocytic cells and suggesting that uPAR may be a useful marker for leukemia typing. Myeloid blast cells from some patients contained intracellular pools of uPAR but displayed no receptor on the cell surface, suggesting that translocation may be a mechanism regulating uPAR expression in these cells. The comparison of uPAR expression between these cell lines and peripheral blood cells and it correlation with plasminogen receptors, tPA receptors and LRP expression offers new insights regarding potential mechanisms for regulation of uPA-uPAR-mediated pericellular proteolysis.
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PMID:Distinct patterns of urokinase receptor (uPAR) expression by leukemic cells and peripheral blood cells. 897 26


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