Project description:Previous in vitro and in vivo studies have demonstrated the potential of using cysteinyl leukotriene receptor antagonists (LTRAs) for chemoprevention, but this has not been investigated in any clinical setting. We therefore investigated the chemopreventive effect of LTRAs in a nationwide population-based study. From the Taiwan National Health Insurance Research Database, we enrolled adults with newly-diagnosed asthma between 2001 and 2011. Among these patients, each LTRA user was matched with five randomly-selected LTRA non-users by sex, age, asthma diagnostic year and modified Charlson Comorbidity Index score. We considered the development of cancer as the outcome. Totally, 4185 LTRA users and 20925 LTRA non-users were identified. LTRA users had a significantly lower cancer incidence rate than LTRA non-users did. Multivariable Cox regression analyses adjusting for baseline characteristics and comorbidities showed LTRA use was an independent protecting factor (hazard ratio = 0.31 [95% CI: 0.24-0.39]), and cancer risk decreased progressively with higher cumulative dose of LTRAs. In conclusion, this study revealed that the LTRA use decreased cancer risk in a dose-dependent manner in asthma patients. The chemopreventive effect of LTRAs deserves further study.
Project description:In our previous genome-wide association study, we demonstrated the association between MHC class I-related chain A (MICA) and hepatocellular carcinoma (HCC) development in patients with chronic hepatitis C. Increasing membrane-bound MICA (mMICA) in cancer cells by reducing MICA sheddases facilitates natural killer (NK) cell-mediated cytotoxicity. Our recent study clarified that A disintegrin and metalloproteases (ADAM), including ADAM9, are MICA sheddases in HCC, and that the suppression of ADAMs increases mMICA, demonstrating the rationality of mMICA-NK targeted therapy. Furthermore, we showed that regorafenib suppresses ADAM9 transcriptionally and translationally. A library of FDA-approved drugs was screened for more efficient inhibitors of ADAM9. Flow cytometry evaluation of the expression of mMICA after treatment with various candidate drugs identified leukotriene receptor antagonists as potential ADAM9 inhibitors. Furthermore, leukotriene receptor antagonists alone or in combination with regorafenib upregulated mMICA, which was in turn downregulated by leukotriene C4 and D4 via ADAM9 function. Our study demonstrates that leukotriene receptor antagonists could be developed as novel drugs for immunological control and suppression of ADAM9 in HCC. Further, leukotriene receptor antagonists should be explored as combination therapy partners with conventional multi-kinase inhibitors for developing therapeutic strategies with enhanced efficacies for HCC management and treatment.
Project description:BackgroundAsthma is the most common chronic condition of childhood. Leukotriene receptor antagonists (LTRAs) are included in international guidelines for children and young people (CYP), but there have been highly publicised concerns about potential adverse effects. The aim was to identify and understand the reported frequency of adverse drug reactions (ADRs) attributed to LTRAs in CYP with asthma.MethodsEmbase, MEDLINE, PubMed and CINAHL were searched up to October 2020. Reference lists of eligible papers were manually screened. Eligible studies identified adverse events attributed to an LTRA in individuals aged between 0 and 18 years diagnosed with asthma. Four different tools were used to assess risk of bias or quality of data to accommodate the papers assessed.ResultsThe search identified 427 papers after deduplication; 15 were included (7 case reports, 7 case-controlled or cohort studies and 1 randomised control trial (RCT)). 7012 patients were recorded, of which 6853 received an LTRA. 13 papers examined the ADRs attributed to montelukast, one to pranlukast and one to unspecified LTRAs. After language standardisation, 48 ADRs were found, 20 of which were psychiatric disorders. Across all studies, the most commonly reported ADRs were 'anxiety', 'sleep disorders' and 'mood disorders'. The frequency of ADRs could be calculated in seven of the eight studies. Applying standardised frequency terms to the prospective studies and RCT, there were 14 'common' and 'uncommon' ADRs. 'Common' ADRs included 'agitation/hyperactivity/irritability/nervousness', 'aggression' and 'headache'. The case reports showed a similar pattern, describing 46 different ADRs experienced by a total of eight patients.ConclusionsLTRAs have a wide range of suspected ADRs in CYP, predominantly gastrointestinal and neuropsychiatric disorders. Careful monitoring of CYP with asthma is required, both to assess and manage ADRs and to step treatment down when clinically stable.Prospero registration numberCRD42020209627.
Project description:BackgroundLeukotriene-receptor antagonists (LTRAs) are recommended as an alternative treatment in patients with mild asthma, but their effect compared with placebo is unclear.PurposeTo determine the benefits and harms of LTRAs as monotherapy or in combination with inhaled corticosteroids compared with placebo in adults and adolescents with asthma.Data sourcesMEDLINE and the Cochrane Central Register of Controlled Trials from inception through June 2015.Study selectionPeer-reviewed, English-language, randomized, controlled trials in patients with asthma that reported the effect of LTRAs versus placebo on measures of asthma control.Data extractionThree researchers extracted data on study population, interventions, outcome measures, and adverse events. One researcher assessed risk of bias.Data synthesisOf the 2008 abstracts that were screened, 50 trials met eligibility criteria. Random-effects meta-analyses of 6 trials of LTRA monotherapy showed that LTRAs reduced the risk for an exacerbation (summary risk ratio [RR], 0.60 [95% CI, 0.44 to 0.81]). In 4 trials of LTRAs as add-on therapy to inhaled corticosteroids, the summary RR for exacerbation was 0.80 (CI, 0.60 to 1.07). Leukotriene-receptor antagonists either as monotherapy or as add-on therapy to inhaled corticosteroids increased FEV1, whereas FEV1 percentage of predicted values was improved only in trials of LTRA monotherapy. Adverse event rates were similar in the intervention and comparator groups.LimitationVariation in definitions and reporting of outcomes, high risk of bias in some studies, heterogeneity of findings, possible selective outcome reporting bias, and inability to assess the effect of asthma severity on summary estimates.ConclusionLeukotriene-receptor antagonists as monotherapy improved asthma control compared with placebo, but which patients are most likely to respond to treatment with LTRAs remains unclear.Primary funding sourceNational Institutes of Health.
Project description:Diagnosing and treating asthma in paediatric patients remains challenging, with many children and adolescents remaining uncontrolled despite treatment. Selecting the most appropriate pharmacological treatment to add onto inhaled corticosteroids (ICS) in children and adolescents with asthma who remain symptomatic despite ICS can be difficult. This literature review compares the efficacy and safety of long-acting β2-agonists (LABAs), leukotriene receptor antagonists (LTRAs) and long-acting muscarinic antagonists (LAMAs) as add-on treatment to ICS in children and adolescents aged 4-17 years.A literature search identified a total of 29 studies that met the inclusion criteria, including 21 randomised controlled trials (RCTs) of LABAs versus placebo, two RCTs of LAMAs (tiotropium) versus placebo, and four RCTs of LTRA (montelukast), all as add-on to ICS. In these studies, tiotropium and LABAs provided greater improvements in lung function than LTRAs, when compared with placebo as add-on to ICS. Although exacerbation data were difficult to interpret, tiotropium reduced the risk of exacerbations requiring oral corticosteroids when added to ICS, with or without additional controllers. LABAs and LTRAs had a comparable risk of asthma exacerbations with placebo when added to ICS. When adverse events (AEs) or serious AEs were analysed, LABAs, montelukast and tiotropium had a comparable safety profile with placebo.In conclusion, this literature review provides an up-to-date overview of the efficacy and safety of LABAs, LTRAs and LAMAs as add-on to ICS in children and adolescents with asthma. Overall, tiotropium and LABAs have similar efficacy, and provide greater improvements in lung function than montelukast as add-on to ICS. All three controller options have comparable safety profiles.
Project description:Leukotriene E4 (LTE4) the most stable of the cysteinyl leukotrienes (cysLTs) binds poorly to classical type 1 (CysLT1) and 2 (CysLT2) receptors although it induces potent responses in human airways in vivo, such as bronchoconstriction, airway hyperresponsiveness and inflammatory cell influx suggesting the presence of a novel receptor that preferentially responds to LTE4. To identify such a receptor two human mast cell lines, LAD2 and LUVA, were selected that differentially responded to LTE4 when analysed by intracellular signalling and gene expression. Comparative transcriptome analysis and recombinant gene overexpression experiments revealed CysLT1 as a receptor responsible for potent LTE4-induced response in LAD2 but not in LUVA cells, an observation confirmed further by gene knockdown and selective inhibitors. Lentiviral overexpression of CysLT1 in LUVA cells augmented intracellular calcium signalling induced by LTE4 but did not restore full agonist responses at the gene expression level. Our data support a model where both an increased expression of Gαq-coupled CysLT1, and sustained intracellular calcium mobilisation and extracellular signal-regulated kinase (Erk) activation, are required for LTE4-mediated regulation of gene expression in human cells. Our study shows for the first time that CysLT1 expression is critically important for responsiveness to LTE4 within a human cell system.
Project description:Background: Cysteinyl leukotrienes (cysLTs) are important mediators of innate immune responsiveness and chronic inflammatory diseases. CysLTs acting through cysteinyl leukotriene receptors may influence the migration and activity of cells such as eosinophils, monocytes and dendritic cells. Objective: To determine the gene expression signature of human monocytes in response to cysLTs and to elucidate the signaling pathways involved in monocyte activation. Methods: Gene expression was analyzed using oligonucleotide microarrays. Responsiveness to cysLTs was assessed by real-time PCR, calcium flux, kinase activation and chemotaxis assays. Results: Cysteinyl leukotriene type I receptor (CysLTR1) transcript 1 is predominantly expressed in human monocytes and cysLTs signal through CysLTR1 in these cells. Several immediate-early genes, including early growth response (Egr) -2, 3, FosB, activating transcription factor 3 and nuclear receptor subfamily 4 were significantly induced by LTD4. This effect was mediated by CysLTR1 coupled to Gαi/o, activation of phospholipase C, and inositol-1,4,5-triphosphate (IP3) and store operated calcium channels. LTD4 induced p38 MAP kinase phosphorylation, a pathway also involved in the regulation of immediate-early genes expression in monocytes. LTD4 stimulated monocyte chemotactic activity that was fully blocked by a selective CysLTR1 inhibitor MK571 and pertussis toxin, suggesting that CysLTR1 coupled to Gαi/o is a dominant functional pathway in human monocytes. Conclusion: Our data show that cysLTs acting through CysLTR1 can significantly influence the activation and migration of human monocytes and that these effects can be fully inhibited by CysLTR1 antagonists. Clinical implications: Antileukotriene therapies are likely to significantly block the proinflammatory functions of human monocytes. Keywords: monocytes stimulated with LTD4
Project description:Leukotriene (LT) D4 contributes to aberrant cytokine networks of classical Hodgkin lymphonoma, This study has investigated LTD4 induced gene expression and pathway in Hodgkin lymphonma cell line L1236.
Project description:BACKGROUND:Cysteinyl leukotrienes (CysLTs) are important mediators of innate immune responsiveness and chronic inflammatory diseases. CysLTs acting through CysLT receptors can influence the migration and activity of cells, such as eosinophils, monocytes, and dendritic cells. OBJECTIVE:We sought to determine the gene expression signature of human monocytes in response to CysLTs and to elucidate the signaling pathways involved in monocyte activation. METHODS:Gene expression was analyzed by using oligonucleotide microarrays. Responsiveness to CysLTs was assessed by using real-time PCR, calcium flux, kinase activation, and chemotaxis assays. RESULTS:CysLT type 1 receptor (CysLTR(1)) transcript 1 is predominantly expressed in human monocytes, and CysLTs signal through CysLTR(1) in these cells. Several immediate-early genes, including early growth response 2 and 3, FBJ murine osteosarcoma viral oncogene homolog B, activating transcription factor 3, and nuclear receptor subfamily 4 were significantly induced by leukotriene (LT) D(4). This effect was mediated by CysLTR(1) coupled to the G protein alpha inhibitory subunit, activation of phospholipase C, and inositol-1,4,5-triphosphate and store-operated calcium channels. LTD(4) induced p38 mitogen-activated protein kinase phosphorylation, a pathway also involved in the regulation of immediate-early gene expression in monocytes. LTD(4) stimulated monocyte chemotactic activity that was fully blocked by a selective CysLTR(1) inhibitor, MK571, and pertussis toxin, suggesting that CysLTR(1) coupled to the G protein alpha inhibitory subunit is a dominant functional pathway in human monocytes. CONCLUSION:Our data show that CysLTs acting through CysLTR(1) can significantly influence the activation and migration of human monocytes and that these effects can be fully inhibited by CysLTR(1) antagonists.
Project description:The cysteinyl leukotrienes (cys-LTs) are proinflammatory lipid mediators acting on the type 1 cys-LT receptor (CysLT(1)R) to mediate smooth muscle constriction and vascular permeability. GPR17, a G protein-coupled orphan receptor with homology to the P2Y and cys-LT receptors, failed to mediate calcium flux in response to leukotriene (LT) D(4) with stable transfectants. However, in stable cotransfections of 6xHis-tagged GPR17 with Myc-tagged CysLT(1)R, the robust CysLT(1)R-mediated calcium response to LTD(4) was abolished. The membrane expression of the CysLT(1)R analyzed by FACS with anti-Myc Ab was not reduced by the cotransfection, yet both LTD(4)-elicited ERK phosphorylation and the specific binding of [(3)H]LTD(4) to microsomal membranes were fully inhibited. CysLT(1)R and GPR17 expressed in transfected cells were coimmunoprecipitated and identified by Western blots, and confocal immunofluorescence microscopy revealed that GPR17 and CysLT(1)R colocalize on the cell surface of human peripheral blood monocytes. Lentiviral knockdown of GPR17 in mouse bone marrow-derived macrophages (BMMPhis) increased both the membrane expression of CysLT(1)R protein by FACS analysis and the LTD(4)-elicited calcium flux in a dose-dependent manner as compared with control BMMPhis, indicating a negative regulatory function of GPR17 for CysLT(1)R in a primary cell. In IgE-dependent passive cutaneous anaphylaxis, GPR17-deficient mice showed a marked and significant increase in vascular permeability as compared with WT littermates, and this vascular leak was significantly blocked by pretreatment of the mice with the CysLT(1)R antagonist, MK-571. Taken together, our findings suggest that GPR17 is a ligand-independent, constitutive negative regulator for the CysLT(1)R that suppresses CysLT(1)R-mediated function at the cell membrane.