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 effects of catalase treatment were studied in two in vitro passaged ascites tumour lines (ATP C+ and EAT) and in three in vitro established human myeloid leukemia cell lines (HL-60; KG-1; KG-1a) characterized by the arrest of cells at different stages of maturation. The results demonstrate that catalase treatment favoured proliferation in the in vitro passaged ascites tumour cells, but not in the in vitro established leukemia lines. Enzyme assays on five in vitro cell lines revealed that catalase was only present in HL-60. Although glutathione peroxidase activity was initially found in all five cell lines, it disappeared from two ascites tumour cells when they were transferred in culture. It is hypothesized that catalase treatment favours ascites tumour cell proliferation because it replaces glutathione peroxidase in eliminating H2O2.
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PMID:Antioxidant enzymes and proliferative activity of cell lines of different origin. 261 35

Possible cytolytic interactions between hydrogen peroxide (H2O2) and neutrophil granule proteins were studied. Preliminary experiments demonstrated synergistic cytolysis when erythro-leukemia targets were exposed to H2O2 combined with a low molecular weight (approximately 3900) granule extract that was predominantly composed of peptide defensins. The synergistic interaction was confirmed when sublytic concentrations of H2O2 were combined with defensin preparations that had been purified to homogeneity. Synergy was concentration dependent in regard to both molecules and could not be explained by trace contamination of defensin preparations with myeloperoxidase. Sequential addition experiments suggested that synergistic lysis required a simultaneous exposure to both cytotoxins. In the presence of sublytic concentrations of H2O2, the binding of iodinated defensin to targets was significantly increased, providing a possible explanation for the observed synergy. Since both molecules are concurrently secreted by activated neutrophils, this interaction may be important during leukocyte-mediated anti-tumor effects or inflammatory tissue injury.
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PMID:Synergistic cytolysis mediated by hydrogen peroxide combined with peptide defensins. 283 69

Various agents induce differentiation of human leukemia cells in vitro. Most of these agents cause myeloid differentiation, but phorbol diesters, 1-alpha,25-dihydroxyvitamin D3 (1,25[OH2]D3), and certain lymphokines cause differentiation to monocyte-like cells. The purpose of this study was to determine the cooperative effects of 1,25(OH2)D3 and the lymphokine gamma interferon (IFN-gamma) on HL-60 cell differentiation. The recombinant human IFN-gamma or 1,25(OH2)D3 caused a slight reduction in the proliferation of the HL-60 cells (30%-40% reduction at doses of 100-200 U/ml [0.25-0.50 nM] IFN-gamma, or 5-25 nM 1,25[OH2]D3). HL-60 cells treated with 100 U/ml IFN-G had an eightfold increase in expression of nonspecific esterase (NSE) and a twofold increase in H2O2 production in response to phorbol myristate acetate (PMA). 1,25(OH2)D3 enhanced NSE expression eight- to 30-fold and H2O2 secretion twofold in response to PMA. There was also enhanced expression of HLA-DR and the receptor for C3bi. The 1,25(OH2)D3- and IFN-gamma-differentiating effects appeared to be additive or synergistic. Populations of IFN-gamma-treated HL-60 cells (but not the 1,25[OH2]D3-treated cells) had multinucleated giant cells. The polykaryons had NSE activity and had some properties of macrophage polykaryons or osteoclasts. 1,25(OH2)D3 did not augment the IFN-gamma-induced polykaryon formation.
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PMID:Cooperative effects of gamma interferon and 1-alpha,25-dihydroxyvitamin D3 in inducing differentiation of human promyelocytic leukemia (HL-60) cells. 308 Mar 26

Soluble immune response suppressor (SIRS), a protein of Mr 14,000, is a lymphokine produced by interferon- or concanavalin A-activated suppressor T cells and is oxidized to its activated form, SIRSox, by H2O2 produced by macrophages. SIRSox inhibits antibody secretion by B lymphocytes and cell division by normal or transformed cell lines. Effects of purified growth factors on suppression of antibody secretion were examined to determine whether any would oppose the inhibitory effects of SIRS or SIRSox. Interleukin 1 (IL-1), interleukin 2 (IL-2), and epidermal growth factor (EGF) each inhibited SIRS-mediated suppression of antibody secretion by cultured mouse spleen cells. Inhibition of SIRS activity was most effective when growth factors were added late in the culture period. IL-1, IL-2, and EGF also blocked suppression by SIRSox. However, EGF and IL-1 blocked suppression by SIRSox only when added 3-6 hr before addition of SIRSox, whereas IL-2 blocked suppression by SIRSox when added before or up to 3 hr after addition of SIRSox. Further evaluation showed that IL-2, but not EGF or IL-1, reversed inhibition of antibody secretion by SIRSox in a time- and concentration-dependent manner. With 50 units of IL-2 per 0.5-ml culture, reversal was complete within 1 hr. The ability of growth factors to interfere with inhibition of cell division by SIRSox was examined with the human B-cell leukemia RPMI-1788. This cell line binds EGF but is not known to have cell surface receptors for IL-1 or IL-2. EGF (0.3-1 ng/ml), when added to RPMI-1788 cultures 4-6 hr before SIRSox, interfered with the ability of SIRSox to inhibit cell division. Taken together, these data indicate that growth factors interfere with both the immunosuppressive and growth inhibitory properties of SIRSox in both heterogeneous and homogeneous cell populations.
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PMID:Inhibition of soluble immune response suppressor activity by growth factors. 387 57

A high molecular weight proteinaceous factor in the cell extract of sarcoma 180 (S-180) was found to inhibit phorbol myristate acetate (PMA)-triggering of macrophage H2O2 release. This factor (S-180 factor) was stable at 56 C for 1 hr and resistant to ultraviolet-irradiation. The S-180 factor inhibited the specific binding of PMA to macrophages and this was accompanied by a parallel reduction of PMA-triggered H2O2 release. S-180 factor preferentially depressed macrophage H2O2 release in response to phorbol diesters including PMA, 4 beta-phorbol 12 13 beta,13 alpha-diacetate, 4 beta-phorbol 12 beta,13 alpha-didecanoate, 4 beta-phorbol 12 beta,13 alpha-dibenzoate, and 4-omicron-methyl-PMA rather than the H2O2 release triggered by wheat germ agglutinin or by phagocytosis of latex particles. The S-180 factor failed to affect the PMA-elicited macrophage cell spreading and macrophage phagocytic activity against latex beads with or without PMA-mediated stimulation. A similar inhibitory factor was found in the extracts of some other murine tumor cells (Ehrlich carcinoma and thymic leukemia) and normal cells (liver, spleen, and peritoneal exudate cells).
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PMID:Suppression of phorbol myristate acetate-triggering of macrophage H2O2 release by sarcoma 180 originating factor. 391 50

Mammalian erythrocytes have large amounts of catalase, an enzyme which catabolizes hydrogen peroxide (H2O2). Because catalase has a low affinity for H2O2, others have suggested that glutathione peroxidase clears most H2O2 within the erythrocyte and that catalase is of little import. We hypothesized that erythrocyte catalase might function to protect heterologous somatic cells against challenge by high levels of exogenous H2O2 (e.g., in areas of inflammation). We find that, whereas nucleated cells (L1210 murine leukemia) are readily killed by an enzymatically generated flux of superoxide (and, therefore, H2O2), the addition of human and murine erythrocytes blocks lethal damage to the target cells. Inhibition of erythrocyte superoxide dismutase, depletion of glutathione, and lysis of the erythrocytes do not diminish this protection. However, inhibition of erythrocyte catalase abrogates the protective effect and the addition of purified catalase (but not superoxide dismutase) restores it. Furthermore, erythrocytes derived from congenitally hypocatalasemic mice (in which other antioxidant systems are intact) do not protect L1210 cells. Our results raise the possibility that the erythrocyte may serve as protection against by-products of its own cargo, oxygen.
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PMID:Erythrocyte catalase. A somatic oxidant defense? 394 56

Rat basophilic leukemia cells have frequently been employed for investigating the pathways of leukotriene biosynthesis, a class of biologically active arachidonic acid metabolites. However, information is lacking on the levels of selenium-dependent glutathione peroxidase (Se-GSH-Px), non-Se-GSH-Px and glutathione S-transferases (GSH-S-Trs), key enzymes involved in fatty acid hydroperoxide metabolism and leukotriene biosynthesis in these cells. Both GSH-S-Trs and non-Se-GSH-Px reactions are catalyzed by the same enzyme. In the present studies, we have measured the enzyme activities of GSH-Px(s) and GSH-S-Trs in the 105,000 X g supernatant fraction of sonified RBL-1 cells. The specific activities for GSH-Px(s) toward H2O2, cumene hydroperoxide, and 15S-hydroperoxy-eicosatetraenoic acid (15S-HPETE) are 12.6, 17.9 and 26.9 nmoles X min-1 X mg-1 protein, respectively. A specific activity of 18.9 nmoles X min-1 X mg-1 protein with 1-chloro-2,4-dinitrobenzene was estimated for the GSH-S-Trs. Therefore, the cell fraction that exhibits 5-lipoxygenase activity also contains selenium and non-selenium glutathione peroxidases.
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PMID:Measurement of glutathione requiring enzymes involved in arachidonic acid cascade of rat basophilic leukemia cells. 644 77

Various human and mouse myeloid leukemia cell lines can differentiate to mature myeloid or monocytoid cells in response to different agents. The myeloblastic leukemia of the RFM/Un mouse (the RF.AML line) was studied here to determine its ability to differentiate after in vitro and in vivo treatment. The RF.AML cells were passed in vivo by i.v. or i.p. injection of freshly harvested leukemic spleen cells or in vitro-passaged leukemia cells. The cells proliferated in the spleen and peritoneal cavity. The RF.AML cells had the appearance of myeloblasts or myelomonoblasts on Wright's stain, had slight positivity for peroxidase, and lacked staining for nonspecific esterase. The cells grew in suspension in vitro with a doubling time of 48 hr. Various phorbol diester tumor promotors inhibited proliferation and incorporation of thymidine into the RF.AML cells. Phorbol myristate acetate (10 to 100 nM) caused the cells to adhere to plastic, and enhanced the phagocytic ability of the cells for Candida albicans. The RF.AML cells had specific receptors for phorbol dibutyrate, binding 0.37 +/- 0.03 (S.E.) pmol of [3H]phorbol dibutyrate/10(6) cells after a 2-hr incubation at 4 degrees with 50 nM [3H]phorbol dibutyrate. Thirty-three to 300 nM dexamethasone caused 19 to 37% of the cells to become nonspecific esterase positive and enhanced their phagocytosis of C. albicans. Likewise, 0.5 or 1.0 microM 13-cis-retinoic acid, or 0.6 or 1.2% dimethyl sulfoxide enhanced the phagocytic ability of the RF.AML cells but had no effect on the adherence, proliferation, or nonspecific esterase activity. None of the treatments induced lysozyme activity in the cells or rendered the RF.AML cells able to produce H2O2 in response to phorbol myristate acetate treatment in vitro. In vivo treatment of mice with RF.AML present with phorbol myristate acetate or dexamethasone did not induce differentiation of the RF.AML cells or alter the survival of the animals. Thus, although the RF.AML cells differentiate in vitro in response to various agents, in vivo differentiation was not seen in this model.
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PMID:Comparison of in vitro and in vivo differentiation of myeloblastic leukemia of the RFM/Un mouse. 659 93

The activation of N2-methyl-9-hydroxyellipticinium acetate (4) by a peroxidase--H2O2 system leads to the formation of an omicron-quinone (7a). This omicron-quinone is not directly generated from the starting material but through a quinone imine intermediate (6) which is subsequently oxidized. This reaction is highly dependent on pH values. The omicron-quinone 7a is easily protonated (7b), gives an addition product with methanol (9), and is reduced by cysteine. The omicron-quinone 7b has a rather low inhibitory effect against L1210 leukemia cell multiplication but acts as an electron carrier and dramatically augments the oxygen consumption in xanthine oxidase-NADH and rat liver microsomes-NADPH systems.
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PMID:omicron-Quinone formation in the biochemical oxidation of the antitumor drug N2-methyl-9-hydroxyellipticinium acetate. 683 91

Giant round pink inclusions (congruent to 2 micrometers) were seen in neutrophilic myeloblasts, promyelocytes, and myelocytes from three patients with acute myelogenous leukemia. On preliminary examination of the bone marrow smears, these inclusions looked like ingested red blood cells in that they were pink and not azurophilic. The bone marrow specimens were processed for the electron microscopic demonstration of peroxidase with 3,3'-diaminobenzidine and H2O2 at pH 7.6. In all three cases, the inclusions were determined to be large peroxidase-positive granules since they were limited by a single unit membrane and, unlike endocytized red blood cells, were not contained within phagocytic vasuoles. The granules were homogeneously dense for peroxidase and showed no obvious crystalline structure when examined stained or unstained on grid. We believe that they correspond to the giant pink round granules Van Slyck and Rebuck observed in immature leukemic granulocytes in 1974 and termed the pseudo-Chediak-Higashi anomaly. Like the giant purple granules seen in leukemia with this anomaly, these granules also appear to be an abnormal variant of peroxidase-positive azurophil (primary) granules. Their lack of azurophilia is due to the absence of sulfated glycoaminoglycans.
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PMID:Electron microscopic and peroxidase cytochemical analysis of pink pseudo-Chediak-Higashi granules in acute myelogenous leukemia. 693 28


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