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Rotondo S, Dell'Elba G, Krauze-Brzósko K, Manarini S, Martelli N, Pecce R, Evangelista V, Cerletti C. Licofelone, a dual lipoxygenase-cyclooxygenase inhibitor, downregulates polymorphonuclear leukocyte and platelet function. Eur J Pharmacol 2002; 453:131-9. [PMID: 12393068 DOI: 10.1016/s0014-2999(02)02385-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Polymorphonuclear leukocytes are strongly implicated in the pathogenesis of inflammatory disease. Polymorphonuclear leukocyte recruitment at sites of inflammation, mainly sustained by the beta2-integrins, is followed by the synthesis and release of inflammatory mediators, such as leukotrienes, proteolytic enzymes and reactive oxygen species. Functional and metabolic interactions between polymorphonuclear leukocytes and platelets can contribute to and exacerbate the process. The effects of the dual 5-lipoxygenase and cyclooxygenase inhibitor licofelone ([2,2-dimethyl-6-(4-chlorophenyl)-7-phenyl-2,3-dihydro-1H-pyrrolizine-5-yl]-acetic acid) were studied on arachidonic acid transcellular metabolism occurring between polymorphonuclear leukocytes and platelets. The formation of leukotriene C(4), a leukotriene A(4)-derived metabolite, by mixed polymorphonuclear leukocyte/platelet suspensions stimulated with 10 microM A23187 was inhibited by licofelone with an IC(50) of 3.8 +/- 0.07 microM. The formation of 5,12-di-hydroxy-eicosatetraenoic acid (HETE) was abolished at concentrations > or = 10 microM. Licofelone also inhibited the generation of reactive oxygen species by polymorphonuclear leukocytes stimulated with 1 microM n-formyl-methionyl-leucyl-phenylalanine (fMLP), 10 nM complement fraction 5a (C5a) and 1 microM platelet activating factor (PAF) with IC(50)s of 24.4 +/- 0.6, 11.0 +/- 1.5 and 11.7 +/-1.2 microM; elastase release induced by the three agonists was inhibited with IC(50)s of 12.2 +/- 2.2, 23.5 +/- 8 and 2.6 +/- 1 microM, respectively. Homotypic polymorphonuclear leukocyte aggregation induced by fMLP, C5A and PAF was inhibited by licofelone with IC(50)s of 23.7 +/- 4.8, 15.6 +/- 3.4 and 15.4 +/- 4 microM, respectively. The present study extends the anti-lipoxygenase and anti-cyclooxygenase activities of licofelone to the production of arachidonic acid metabolites generated as a consequence of polymorphonuclear leukocyte-platelet transcellular metabolism and to polymorphonuclear leukocyte responses relevant to the pathogenesis of inflammation. The coexistence within the same molecule of a wide spectrum of anti-inflammatory properties is of interest.
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Affiliation(s)
- Serenella Rotondo
- G Bizzozero Laboratory of Blood and Vascular Cell Interactions, Istituto di Ricerche Farmacologiche Mario Negri, Consorzio Mario Negri Sud, Via Nazionale, Santa Maria Imbaro 66030, Italy
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2
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Sperker B, Tomkiewicz C, Burk O, Barouki R, Kroemer HK. Regulation of human beta-glucuronidase by A23187 and thapsigargin in the hepatoma cell line HepG2. Mol Pharmacol 2001; 59:177-82. [PMID: 11160851 DOI: 10.1124/mol.59.2.177] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
A novel approach to reducing organ toxicity of anticancer agents is the application of nontoxic glucuronide prodrugs from which the active drug is released by human beta-glucuronidase, an enzyme present at high levels in many tumors. In view of high interindividual variability in beta-glucuronidase expression, regulation of this enzyme is an essential factor modulating bioactivation of glucuronide prodrugs. However, data on regulation of human beta-glucuronidase expression are not available. Preliminary evidence from animal experiments points to a role of intracellular calcium in regulation of beta-glucuronidase activity. Therefore, we investigated regulation of beta-glucuronidase by the calcium ionophore A23187 and the calcium ATPase inhibitor thapsigargin in the human hepatoma cell line HepG2. The enzyme was characterized on activity, protein, and mRNA levels by cleavage of 4-methylumbelliferyl-beta-D-glucuronide, Western blotting, Northern blotting, and nuclear run-on transcription. Incubation of HepG2 cells with A23187 and thapsigargin, respectively, revealed a time and concentration dependent down-regulation of beta-glucuronidase activity to about 50% of the control level. This effect could also be demonstrated in several other cell lines (e.g., HL-60, ECV 304, 32M1, Caco-2/TC7). Effects on protein and mRNA levels paralleled those obtained on enzymatic activity. In line with these data, A23187 and thapsigargin decreased beta-glucuronidase transcriptional rate. Our data demonstrate regulation of human beta-glucuronidase by xenobiotics. Down-regulation of beta-glucuronidase by A23187 and thapsigargin is at least partly mediated by a transcriptional mechanism. Based on our findings, we speculate that beta-glucuronidase activity and hence bioactivation of glucuronide prodrugs in humans can be modulated by exogenous factors.
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Affiliation(s)
- B Sperker
- Institut für Pharmakologie, Ernst Moritz Arndt Universität Greifswald, Greifswald, Germany.
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Sitrin RG, Pan PM, Harper HA, Todd RF, Harsh DM, Blackwood RA. Clustering of urokinase receptors (uPAR; CD87) induces proinflammatory signaling in human polymorphonuclear neutrophils. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2000; 165:3341-9. [PMID: 10975852 DOI: 10.4049/jimmunol.165.6.3341] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Leukocytes use urokinase receptors (uPAR; CD87) in adhesion, migration, and proteolysis of matrix proteins. Typically, uPAR clusters at cell-substratum interfaces, at focal adhesions, and at the leading edges of migrating cells. This study was undertaken to determine whether uPAR clustering mediates activation signaling in human polymorphonuclear neutrophils. Cells were labeled with fluo-3/AM to quantitate intracellular Ca2+ ([Ca2+]i) by spectrofluorometry, and uPAR was aggregated by Ab cross-linking. Aggregating uPAR induced a highly reproducible increase in [Ca2+]i (baseline to peak) of 295 +/- 37 nM (p = 0.0002). Acutely treating cells with high m.w. urokinase (HMW-uPA; 4000 IU/ml) produced a response of similar magnitude but far shorter duration. Selectively aggregating uPA-occupied uPAR produced smaller increases in [Ca2+]i, but saturating uPAR with HMW-uPA increased the response to approximate that of uPAR cross-linking. Cross-linking uPAR induced rapid and significant increases in membrane expression of CD11b and increased degranulation (release of beta-glucuronidase and lactoferrin) to a significantly greater degree than cross-linking control Abs. The magnitude of degranulation correlated closely with the difference between baseline and peak [Ca2+]i, but was not dependent on the state of uPA occupancy. By contrast, selectively cross-linking uPA-occupied uPAR was capable of directly inducing superoxide release as well as enhancing FMLP-stimulated superoxide release. These results could not be duplicated by preferentially cross-linking unoccupied uPAR. We conclude that uPAR aggregation initiates activation signaling in polymorphonuclear neutrophils through at least two distinct uPA-dependent and uPA-independent pathways, increasing their proinflammatory potency (degranulation and oxidant release) and altering expression of CD11b/CD18 to favor a firmly adherent phenotype.
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Affiliation(s)
- R G Sitrin
- Pulmonary and Critical Care Medicine Division, University of Michigan, Ann Arbor, MI 48109, USA.
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Bossù E, Aglianò AM, Desideri N, Sestili I, Porrà R, Grandilone M, Quaglia MG. LTB4 as marker of 5-LO inhibitory activity of two new N-omega-ethoxycarbonyl-4-quinolones. J Pharm Biomed Anal 1999; 19:539-48. [PMID: 10704120 DOI: 10.1016/s0731-7085(98)00250-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The supposed 5-LO inhibitory activity of two N-omega-ethoxycarbonyl-4-quinolones was tested determining leukotriene B4 (LTB4) in RBL-1 cell cultures, pretreated with the two compounds of interest. LTB4, obtained by solid-phase extraction (SPE) from cell cultures supernatants, was determined by micellar electrokinetic chromatography (MEKC). The analysis was performed using an uncoated capillary, filled with borate buffer at pH 8.3, containing 12.5 mM SDS as micelles generator. Therefore, following the decreasing of LTB4 it was possible to verify the 5-LO inhibitory activity of two quinolone derivatives. To asses the suitability of the use of LTB4 as marker of the activity of the new compounds, the analysis was repeated using quercetin, a well known 5-LO inhibitor.
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MESH Headings
- 12-Hydroxy-5,8,10,14-eicosatetraenoic Acid/analysis
- Animals
- Arachidonate 5-Lipoxygenase/metabolism
- Biomarkers/analysis
- Calcimycin/pharmacology
- Chromatography, High Pressure Liquid
- Chromatography, Micellar Electrokinetic Capillary
- Culture Media, Conditioned/chemistry
- Electrophoresis, Capillary
- Enzyme Activation/drug effects
- Evaluation Studies as Topic
- Hydroxyeicosatetraenoic Acids/analysis
- Leukemia, Basophilic, Acute/enzymology
- Leukemia, Basophilic, Acute/pathology
- Leukotriene B4/analysis
- Leukotriene B4/metabolism
- Lipoxygenase Inhibitors/pharmacology
- Prostaglandins B/analysis
- Quercetin/pharmacology
- Quinolones/pharmacology
- Rats
- Sodium Dodecyl Sulfate/chemistry
- Tumor Cells, Cultured
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Affiliation(s)
- E Bossù
- Centro di Studio per la Chimica del Farmaco del CNR presso il Dip Studi Farmaceutici della Università La Sapienza, Rome, Italy
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Adhesion-Dependent Release of Elastase From Human Neutrophils in a Novel, Flow-Based Model: Specificity of Different Chemotactic Agents. Blood 1998. [DOI: 10.1182/blood.v92.12.4819] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
AbstractNeutrophils must adhere to the vessel wall, migrate, and degranulate in an ordered manner to perform their protective function. Disruption of these processes may be pathogenic. Current knowledge of the degranulation process is derived almost exclusively from studies on neutrophils in suspension, in which priming with the nonphysiological agent cytochalasin B is necessary to obtain elastase release in response to activating agents. To avoid this, we have adopted a different approach. Using a novel flow-based adhesion system, we have been able to quantify the release of elastase from the primary granules of activated neutrophils adherent to immobilized platelets or purified receptors without priming. Comparing stimuli, formyl tripeptide (fMLP), interleukin-8 (IL-8), activated complement fragment C5a, and platelet-activating factor (PAF) all induced rapid conversion to CD11b/CD18 (MAC-1) -mediated stationary adhesion when perfused over neutrophils already rolling on platelet monolayers or purified P-selectin. However, fMLP, C5a, and IL-8, but not PAF, induced release of elastase from the adherent cells in minutes. Neutrophils stimulated in suspension showed little degranulation. Treatment of neutrophils with an inhibitor of 5-lipoxygenase–activating protein (MK886) and thus synthesis of leukotrienes (LTs) or with an antagonist of the LTB4 receptor (LY223982) blocked the release of elastase. This indicated that endogenous synthesis of 5-lipoxygenase products such as LTs and autocrine activation of neutrophils was required for fMLP-driven elastase release. We hypothesize that the differential ability of PAF and fMLP to induce elastase release from surface-adherent neutrophils could arise from differential ability to generate leukotrienes, such as LTB4, and would be an appropriate mechanism for the control of elastase release during inflammation in vivo, where it is important that cytotoxic agents are not released until activated neutrophils have migrated into the extravascular tissues.
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Adhesion-Dependent Release of Elastase From Human Neutrophils in a Novel, Flow-Based Model: Specificity of Different Chemotactic Agents. Blood 1998. [DOI: 10.1182/blood.v92.12.4819.424k16_4819_4827] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Neutrophils must adhere to the vessel wall, migrate, and degranulate in an ordered manner to perform their protective function. Disruption of these processes may be pathogenic. Current knowledge of the degranulation process is derived almost exclusively from studies on neutrophils in suspension, in which priming with the nonphysiological agent cytochalasin B is necessary to obtain elastase release in response to activating agents. To avoid this, we have adopted a different approach. Using a novel flow-based adhesion system, we have been able to quantify the release of elastase from the primary granules of activated neutrophils adherent to immobilized platelets or purified receptors without priming. Comparing stimuli, formyl tripeptide (fMLP), interleukin-8 (IL-8), activated complement fragment C5a, and platelet-activating factor (PAF) all induced rapid conversion to CD11b/CD18 (MAC-1) -mediated stationary adhesion when perfused over neutrophils already rolling on platelet monolayers or purified P-selectin. However, fMLP, C5a, and IL-8, but not PAF, induced release of elastase from the adherent cells in minutes. Neutrophils stimulated in suspension showed little degranulation. Treatment of neutrophils with an inhibitor of 5-lipoxygenase–activating protein (MK886) and thus synthesis of leukotrienes (LTs) or with an antagonist of the LTB4 receptor (LY223982) blocked the release of elastase. This indicated that endogenous synthesis of 5-lipoxygenase products such as LTs and autocrine activation of neutrophils was required for fMLP-driven elastase release. We hypothesize that the differential ability of PAF and fMLP to induce elastase release from surface-adherent neutrophils could arise from differential ability to generate leukotrienes, such as LTB4, and would be an appropriate mechanism for the control of elastase release during inflammation in vivo, where it is important that cytotoxic agents are not released until activated neutrophils have migrated into the extravascular tissues.
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Burchardt ER, Müller-Peddinghaus R. Antiedematous effects of combination therapies with the leukotriene synthesis inhibitor BAY X 1005 in the archidonic acid-induced mouse ear inflammation test. Prostaglandins Leukot Essent Fatty Acids 1997; 56:301-6. [PMID: 9150376 DOI: 10.1016/s0952-3278(97)90574-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The leukotriene synthesis inhibitor (LSI) BAY X 1005 was tested in the arachidonic acid (AA)-induced mouse ear inflammation test (AA-MEIT) alone and in combination with other representative anti-inflammatory compounds for antiedematous effects. When BAY X 1005 was used as a monotherapy, the ED50 (half-maximal effect) was observed at 5.1 mg/kg per os (p.o.) and at 0.8 microg for topical application. The maximal inhibition of edema formation was estimated to be 63% for p.o. application and 54% for topical application. Furthermore, experiments were carried out in which the animals were conditioned with a combination of the H1/5-HT receptor antagonists pyrilamine and methysergide in addition to treatment with BAY X 1005. This conditioning treatment alone, without BAY X 1005, resulted in a 45 +/- 13% reduction in edema formation. ED50 substance effects were observed at 5.3 mg/kg p.o. and at 0.02 microg per ear for topical application. The maximal inhibition of edema formation in the conditioned groups was 82% for the oral administration of BAY X 1005 and 72% for the topical application. To further characterize the antiinflammatory properties of BAY X 1005 in the conditioned and unconditioned AA-MEIT, BAY X 1005 was tested in combination with the nitric oxide (NO) synthase inhibitor L-NAME, with the cyclooxygenase inhibitor indomethacin, and in combination with both compounds. BAY X 1005 consistently exerted anti-inflammatory effects in the AA-MEIT. The effects of a combination of different inhibitors of inflammatory mediators were not simply additive in this model, as was demonstrated in the case of the combination of L-NAME and indomethacin where a smaller inhibition than with either substance alone was observed. In the conditioned model, a combination of BAY X 1005 with L-NAME or indomethacin, or with both compounds together was less effective than the monotherapy with BAY X 1005. Taken together, these data suggest that cyclooxygenase products and NO have little effect on edema formation in the conditioned and unconditioned AA-MEIT model and that their interaction with leukotrienes is of minor quantitative importance. Our results underline the complexity of the AA-MEIT model and provide a rationale for H1/5-HT-conditioning animals to compensate for peculiarities in the mouse-specific mediator spectrum and to recognize the importance of the leukotriene-specific inflammatory response.
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Affiliation(s)
- E R Burchardt
- Bayer AG, Pharma Research Center, Institute for Cardiovascular and Arteriosclerosis Research, Wuppertal, Germany
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Brock TG, McNish RW, Peters-Golden M. Translocation and leukotriene synthetic capacity of nuclear 5-lipoxygenase in rat basophilic leukemia cells and alveolar macrophages. J Biol Chem 1995; 270:21652-8. [PMID: 7665580 DOI: 10.1074/jbc.270.37.21652] [Citation(s) in RCA: 110] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Leukotriene (LT) synthesis involves the translocation of enzymatically active 5-lipoxygenase (5-LO) from a soluble site to a bound site, where it interacts with 5-lipoxygenase-activating protein (FLAP). In human polymorphonuclear leukocytes (PMNs), 5-LO moves from the cytosol to the nuclear envelope (NE) to interact with FLAP. However, 5-LO has recently been found within the nucleus, as well as the cytosol, of rat basophilic leukemia (RBL) cells and alveolar macrophages (AMs). To assess whether nuclear 5-LO can contribute to LT synthesis in these cells, we investigated whether this enzyme pool 1) translocates upon cell activation, 2) colocalizes with FLAP, and 3) is enzymatically active. By cell fractionation followed by immunoblotting, both cytosolic and nuclear soluble 5-LO decreased dramatically in RBL cells following activation with the calcium ionophore A23187. Concurrently, 5-LO increased in the pelletable nuclear pool, where FLAP was also detected. The loss of both cytosolic and nuclear soluble 5-LO, with concomitant increase exclusively at the NE, as well as co-localization with FLAP, were confirmed by indirect immunofluorescent and confocal microscopy. In AMs, the nuclear soluble pool of 5-LO moved to the NE, where FLAP was also found; however, the cytosolic 5-LO pool did not translocate. Application of these methods to PMNs confirmed that cytosolic 5-LO moved to the nuclear envelope and co-localized with FLAP. By cell-free assay, nuclear soluble proteins from both RBL cells and AMs, but not PMNs, were able to generate 5-LO products from arachidonate, and this was inhibited by the direct 5-LO inhibitor zileuton. Cytosolic proteins from all cell types also showed cell-free 5-LO activity. These results demonstrate three distinct patterns of 5-LO translocation that are specific for each cell type: translocation of only a cytosolic pool in PMNs, of only a nuclear pool in AMs, and of both cytosolic and nuclear pools in RBL cells. By virtue of its enzymatic activity and ability to translocate, nuclear 5-LO has the potential to contribute to LT synthesis in RBL cells and AMs. Finally, these results provide a foundation for considering the individual functions of discrete pools of 5-LO in future studies.
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Affiliation(s)
- T G Brock
- Department of Internal Medicine, University of MIchigan Medical Center, Ann Arbor 48109-0652, USA
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Hatzelmann A, Fruchtmann R, Mohrs KH, Raddatz S, Matzke M, Pleiss U, Keldenich J, Müller-Peddinghaus R. Mode of action of the leukotriene synthesis (FLAP) inhibitor BAY X 1005: implications for biological regulation of 5-lipoxygenase. AGENTS AND ACTIONS 1994; 43:64-8. [PMID: 7741044 DOI: 10.1007/bf02005767] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Five-lipoxygenase (5-LOX) inhibition is gaining increasing importance as a novel approach to therapy of allergic asthma and other inflammatory diseases. Presently, two types of inhibitors are known, direct 5-LOX inhibitors (LOI) and the FLAP (five lipoxygenase activating protein) binding leukotriene synthesis inhibitors (LSI). The 5-LOX selective and orally active quinoline LSI, BAY X 1005, shares many mechanistic features with the indole LSI, MK-886. The binding of BAY X 1005 to FLAP correlates with LTB4 synthesis inhibition. BAY X 1005 has been shown to bind to the 18 kD protein FLAP. BAY X 1005 inhibits 5-LOX translocation from the cytosol to membranes and reverses 5-LOX translocation. The use of BAY X 1005 has helped to elucidate part of the complex FLAP/5-LOX interaction by showing that FLAP appears to represent a 5-LOX substrate transfer protein channelling endogenous and exogenous arachidonic acid to the leukotriene synthetizing 5-LOX. This notion presented by our group in 1992 has stimulated further mechanistic studies. These findings have additionally led to the hypothesis that substrate competition is not confined to the LSI/FLAP interaction but may also be true for the LOI/5-LOX interaction and that even mixed LSI/LOI 5-LOX inhibitors are feasible, yet have not been described. Further mechanistic work on LSI will be orientated not only to further elucidate the complex FLAP/5-LOX interaction, but also to identify FLAP-related eicosanoid binding proteins.
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Affiliation(s)
- A Hatzelmann
- Bayer AG, Pharma Research Center, Wuppertal, Germany
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