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BACKGROUND: The C-type lectin family 18 (CLEC18) with lipid and glycan binding capabilities is important to metabolic regulation and innate immune responses against viral infection. However, human CLEC18 comprises three paralogous genes with highly similar sequences, making it challenging to distinguish genetic variations, expression patterns, and biological functions of individual CLEC18 paralogs. Additionally, the evolutionary relationship between human CLEC18 and its counterparts in other species remains unclear. METHODS: To identify the sequence variation and evolutionary divergence of human CLEC18 paralogs, we conducted a comprehensive analysis using various resources, including human and non-human primate reference genome assemblies, human pangenome assemblies, and long-read-based whole-genome and -transcriptome sequencing datasets. RESULTS: We uncovered paralogous sequence variants (PSVs) and polymorphic variants (PVs) of human CLEC18 proteins, and identified distinct signatures specific to each CLEC18 paralog. Furthermore, we unveiled a novel segmental duplication for human CLEC18A gene. By comparing CLEC18 across human and non-human primates, our research showed that the CLEC18 paralogy probably occurred in the common ancestor of human and closely related non-human primates, and the lipid-binding CAP/SCP/TAPS domain of CLEC18 is more diverse than its glycan-binding CTLD. Moreover, we found that certain amino acids alterations at variant positions are exclusive to human CLEC18 paralogs. CONCLUSIONS: Our findings offer a comprehensive profiling of the intricate variations and evolutionary characteristics of human CLEC18.
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Évolution moléculaire , Variation génétique , Lectines de type C , Humains , Lectines de type C/génétique , Lectines de type C/métabolisme , Animaux , Primates/génétiqueRÉSUMÉ
Immunoglobulin A nephropathy (IgAN) is an autoimmune disease characterized by abnormal IgA deposition in glomerulus. Current diagnosis of IgAN still depends on renal biopsy, an invasive method that might increase the risk of clinical outcomes. Therefore, we aimed to explore the characteristics of T cell repertoire in IgAN from peripheral blood samples for identifying innovative diagnostic biomarkers. Herein, we included 8 IgAN patients, 25 non-IgAN patients, and 10 healthy controls in the study. A high-throughput immune repertoire sequencing was conducted to investigate the T-cell receptor beta-chain (TCRß) repertoire of peripheral blood. Characteristics of TCRß repertoire were assessed for these three distinct groups. A reduced TCRß repertoire diversity was observed in IgAN patients compared to non-IgAN and healthy individuals. A skewed distribution toward shorter TCRß complementarity determining region (CDR3) length was found in non-IgAN relative to IgAN patients. In addition, the differences in usages of five TRBV genes (TRBV5-4, TRBV6-4, TRBV12-1, TRBV16, and TRBV21-1) were identified between IgAN, non-IgAN, and healthy subjects. Of note, the TRBV6-4 gene, which is associated with mucosal-associated invariant T (MAIT) cells, exhibited higher usage in IgAN patients, suggesting potential importance of MAIT cells in IgAN. In short, our findings supported TCR repertoire characteristics as potential biomarkers for IgAN diagnosis.
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INTRODUCTION: Ankylosing spondylitis (AS) is a chronic inflammatory autoimmune disease in which T-cell immune responses play important roles. AS has been characterized by altered T-cell receptor (TCR) repertoire profiles, which are thought to be caused by expansion of disease-related TCR clonotypes. However, how biological agents affect the TCR repertoire status and whether their therapeutic outcomes are associated with certain features or dynamic patterns of the TCR repertoire are still elusive. MATERIAL AND METHODS: We collected clinical samples from AS patients pre- and post-treatment with biologics. TCR repertoire sequencing was conducted to investigate associations of TCRα and TCRß repertoire characteristics with disease activity and inflammatory indicators/cytokines. RESULTS: Our results showed that good responders were associated with an increase in the TCR repertoire diversity with higher proportions of contracted TCR clonotypes. Additionally, we further identified a positive correlation between TCR repertoire diversity and interleukin (IL)-23 levels in AS patients. A network analysis revealed that contracted AS-associated TCR clonotypes with the same complementary-determining region 3 (CDR3) motifs, which represented high probabilities of sharing TCR specificities to AS-related antigens, were dominant in good responders of AS after treatment with biologic therapies. CONCLUSIONS: Our findings suggested an important connection between TCR repertoire changes and therapeutic outcomes in biologic-treated AS patients. The status and dynamics of TCR repertoire profiles are useful for assessing the prognosis of biologic treatments in AS patients.
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Pelvispondylite rhumatismale , Humains , Pelvispondylite rhumatismale/traitement médicamenteux , Lymphocytes T , Biothérapie , Pronostic , Maladie chronique , Récepteurs aux antigènes des cellules T/génétiqueRÉSUMÉ
Introduction: Cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) are considered for patients with peritoneal metastasis (PM). However, patients selection that relies on conventional prognostic factors is not yet optimal. In this study, we performed whole exome sequencing (WES) to establish tumor molecular characteristics and expect to identify prognosis profiles for PM management. Methods: In this study, blood and tumor samples were collected from patients with PM before HIPEC. Tumor molecular signatures were determined using WES. Patient cohort was divided into responders and non-responders according to 12-month progression-free survival (PFS). Genomic characteristics between the two cohorts were compared to study potential targets. Results: In total, 15 patients with PM were enrolled in this study. Driver genes and enriched pathways were identified from WES results. AGAP5 mutation was found in all responders. This mutation was significantly associated with better OS (p = 0.00652). Conclusions: We identified prognostic markers that might be useful to facilitate decision-making before CRS/HIPEC.
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Cancer immunotherapies are treatments that use drugs or cells to activate patients' own immune systems against cancer cells. Among them, cancer vaccines have recently been rapidly developed. Based on tumor-specific antigens referred to as neoantigens, these vaccines can be in various forms such as messenger (m)RNA and synthetic peptides to activate cytotoxic T cells and act with or without dendritic cells. Growing evidence suggests that neoantigen-based cancer vaccines possess a very promising future, yet the processes of immune recognition and activation to relay identification of a neoantigen through the histocompatibility complex (MHC) and T-cell receptor (TCR) remain unclear. Here, we describe features of neoantigens and the biological process of validating neoantigens, along with a discussion of recent progress in the scientific development and clinical applications of neoantigen-based cancer vaccines.
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OBJECTIVE: To investigate the changes of Spike protein-HLA binding affinity profiles between the Wuhan strain and two dominant variants, the Delta and the Omicron strains, among the Taiwanese, the British and the Russian populations. METHODS: The HLA frequencies and the HLA-peptide binding affinity profiles in the T-CoV database were combined to conduct the study. We focused on the public alleles in the three populations (HLA-A, HLA-B, HLA-C, HLA-DRB1, and/or HLA-DPA1/DPB1 alleles) and the altered peptides of the spike protein (compared to the Wuhan strain) in the Delta G/478K·V1 (B.1.617.2 + AY.1 + AY.2) and the Omicron (BA.1) strains. RESULTS: For the Delta strain, tight bindings of the altered peptides to the HLA alleles decrease in all three populations and almost vanish in the Taiwanese population. For the Omicron strain, tight bindings are mostly preserved for both HLA classes and in the Taiwanese and the British populations, with a slight reduction in HLA class II in the Taiwanese (1.4%), while the Russian population preserves a relatively high fraction of tight bindings for both HLA classes. CONCLUSION: We comprehensively reported the changes in the HLA-associated SARS-CoV-2 Spike protein peptide binding profiles among the Taiwanese, the British, and the Russian populations. Further studies are needed to understand the immunological mechanisms and the clinical value of our findings.
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COVID-19 , Glycoprotéine de spicule des coronavirus , Humains , Glycoprotéine de spicule des coronavirus/génétique , SARS-CoV-2/génétique , COVID-19/épidémiologie , COVID-19/génétiqueRÉSUMÉ
Aldosterone-producing adenoma (APA) is a benign adrenal tumor that results in persistent hyperaldosteronism. As one major subtype of primary aldosteronism, APA leads to secondary hypertension that is associated with immune dysregulation. However, how the adaptive immune system, particularly the T-cell population, is altered in APA patients remains largely unknown. Here, we performed TCR sequencing to characterize the TCR repertoire between two age-matched groups of patients: one with APA and the other one with essential hypertension (EH). Strikingly, we found a significant reduction of TCR repertoire diversity in the APA group. Analyses on TCR clustering and antigen annotation further showed that the APA group possessed lower diversity in TCR clonotypes with non-common antigen-specific features, compared with the EH group. In addition, our results indicated that the strength of correlation between generation probabilities and frequencies of TCR clonotypes was significantly higher in the APA group than that in the EH group. Finally, we observed that clinical features, including plasma aldosterone level, aldosterone-renin ratio, and blood sodium level, were positively associated with the strength of correlation between generation and abundance of TCR clonotypes in the APA group. Our findings unveiled the correlation between T-cell immune repertoire and APA, suggesting a critical role of such adrenal adenoma in the T-cell immunity of patients with hypertension.
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Adénomes , Hypertension artérielle , Adénomes/génétique , Aldostérone , Hypertension essentielle/complications , Humains , Hypertension artérielle/complications , Récepteurs aux antigènes des cellules T/génétique , RénineRÉSUMÉ
Marfan syndrome (MFS) is a rare disease that affects connective tissue, which causes abnormalities in several organ systems including the heart, eyes, bones, and joints. The autosomal dominant disorder was found to be strongly associated with FBN1, TGFBR1, and TGFBR2 mutations. Although multiple genetic mutations have been reported, data from Asian populations are still limited. As a result, we utilized the whole exome sequencing (WES) technique to identify potential pathogenic variants of MFS in a Taiwan cohort. In addition, a variety of annotation databases were applied to identify the biological functions as well as the potential mechanisms of candidate genes. In this study, we confirmed the pathogenicity of FBN1 to MFS. Our results indicated that TTN and POMT1 may be likely related to MFS phenotypes. Furthermore, we found nine unique variants highly shared in a MFS family cohort, of which eight are novel variants worthy of further investigation.
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The coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has become a public health emergency. The most common symptoms of COVID-19 are fever, cough, and fatigue. While most patients with COVID-19 present with mild illness, some patients develop pneumonia, an important risk factor for mortality, at early stage of viral infection, putting these patients at increased risk of death. So far, little has been known about differences in the T cell repertoires between COVID-19 patients with and without pneumonia during SARS-CoV-2 infection. Herein, we aimed to investigate T cell receptor (TCR) repertoire profiles and patient-specific SARS-CoV-2-associated TCR clusters between COVID-19 patients with mild disease (no sign of pneumonia) and pneumonia. The TCR sequencing was conducted to characterize the peripheral TCR repertoire profile and diversity. The TCR clustering and CDR3 annotation were exploited to further discover groups of patient-specific TCR clonotypes with potential SARS-CoV-2 antigen specificities. Our study indicated a slight decrease in the TCR repertoire diversity and a skewed CDR3 length usage in patients with pneumonia compared to those with mild disease. The SARS-CoV-2-associated TCR clusters enriched in patients with mild disease exhibited significantly higher TCR generation probabilities and most of which were highly shared among patients, compared with those from pneumonia patients. Importantly, using similarity network-based clustering followed by the sequence conservation analysis, we found different patterns of CDR3 sequence motifs between mild disease- and pneumonia-specific SARS-CoV-2-associated public TCR clusters. Our results showed that characteristics of overall TCR repertoire and SARS-CoV-2-associated TCR clusters/clonotypes were divergent between COVID-19 patients with mild disease and patients with pneumonia. These findings provide important insights into the correlation between the TCR repertoire and disease severity in COVID-19 patients.
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COVID-19/immunologie , Pneumopathie infectieuse/immunologie , Récepteurs aux antigènes des cellules T/génétique , SARS-CoV-2/physiologie , Lymphocytes T/immunologie , Adulte , Sujet âgé , Évolution de la maladie , Femelle , Humains , Mâle , Adulte d'âge moyen , Pandémies , Récepteurs aux antigènes des cellules T/métabolisme , Analyse de séquence d'ADN , Indice de gravité de la maladieRÉSUMÉ
Rheumatoid arthritis (RA) is a systematic autoimmune disease, predominantly causing chronic polyarticular inflammation and joint injury of patients. For the treatment of RA, biologic disease-modifying antirheumatic drugs (bDMARDs) have been used to reduce inflammation and to interfere with disease progression through targeting and mediating the immune system. Although the therapeutic effects of bDMARDs in RA patients have been widely reported, whether these drugs also play important roles in T-cell repertoire status is still unclear. We therefore designed the study to identify the role of T-cell repertoire profiles in RA patients with different types of bDMARD treatments. A high-throughput sequencing approach was applied to profile the T-cell receptor beta chain (TCRB) repertoire of circulating T lymphocytes in eight patients given adalimumab (anti-TNF-α) with/without the following use of either rituximab (anti-CD20) or tocilizumab (anti-IL6R). We subsequently analyzed discrepancies in the clonal diversity and CDR3 length distribution as well as usages of the V and J genes of TCRB repertoire and interrogated the association between repertoire diversity and disease activities followed by the treatment of bDMARDs in these RA patients. All groups of patients showed well-controlled DAS28 scores (<2.6) after different treatment regimens of drugs and displayed no significant statistical differences in repertoire diversity, distribution of CDR3 lengths, and usage of V and J genes of TCRB. Nonetheless, a trend between overall TCRB repertoire diversity and disease activity scores in all bDMARD-treated RA patients was observed. Additionally, age was found to be associated with repertoire diversity in RA patients treated with bDMARDs. Through the profiling of the TCR repertoire in RA patients receiving different biologic medications, our study indicated an inverse tendency between TCR repertoire diversity and disease activity after biologic treatment in RA patients.
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Antirhumatismaux/usage thérapeutique , Polyarthrite rhumatoïde/métabolisme , Biothérapie/méthodes , Marqueurs biologiques/analyse , Récepteurs aux antigènes des cellules T/métabolisme , Facteur de nécrose tumorale alpha/antagonistes et inhibiteurs , Adulte , Sujet âgé , Polyarthrite rhumatoïde/traitement médicamenteux , Polyarthrite rhumatoïde/anatomopathologie , Études cas-témoins , Évolution de la maladie , Femelle , Études de suivi , Humains , Mâle , Adulte d'âge moyen , Pronostic , Récepteurs aux antigènes des cellules T/génétiqueRÉSUMÉ
The phthalate plasticizer, di(2-ethyl-hexyl) phthalate (DEHP), and its derived metabolites are common anthropogenic environmental toxins, which are known to act as endocrine disruptors. Numerous studies have associated DEHP with disruption of sex hormones, abnormal development of reproductive organs, allergies, and inflammation. Its role in promoting inflammation has been reported by both human epidemiological and animal studies. In stomach tissue, chronic inflammation is known to accompany mucosal damage, and pave the way to gastritis, stomach ulcers, and ultimately gastric cancer. Eastern Asian populations possess the highest gastric cancer incidences in the world. Coincidentally, East Asia is one of the world's major sites for plastics manufacture and export. Thus, possible correlations between DEHP, a common plasticizer, and gastric cancer are of great interest. Our study revealed several critical findings. First, even at very low dosage, mimicking the residual plasticizer exposure, detrimental effects of DEHP on gastric cells can be detected. Second, gastric cells treated with DEHP increased cyclooxygenase-2 (COX-2) in a time-dependent manner. Third, promoter deletion studies revealed a critical role of nuclear factor-kappa B (NF-κB) for COX-2 gene responses. Finally, our results indicated that a low concentration of DEHP is able to trigger COX-2 activation via the extracellular signal-regulated kinase (ERK1/2) and NF-κB signaling pathway. Taken together, we demonstrate that very low doses of DEHP enhance the expression of the prototypical inflammatory gene, COX-2, in gastric cancer cells via ERK1/2 and NF-κB activation. This study provides important insights into the inflammatory process and damages associated with phthalate plasticizers exposure.
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Cyclooxygenase 2/métabolisme , Phtalate de bis[2-éthylhexyle]/toxicité , Régulation de l'expression des gènes/effets des médicaments et des substances chimiques , Plastifiants/toxicité , Adénocarcinome , Animaux , Lignée cellulaire tumorale , Phtalate de bis[2-éthylhexyle]/métabolisme , Polluants environnementaux/composition chimique , Polluants environnementaux/métabolisme , Polluants environnementaux/toxicité , Humains , Mitogen-Activated Protein Kinase 1/métabolisme , Mitogen-Activated Protein Kinase 3/métabolisme , Facteur de transcription NF-kappa B/antagonistes et inhibiteurs , Facteur de transcription NF-kappa B/génétique , Facteur de transcription NF-kappa B/métabolisme , Plastifiants/métabolisme , Interférence par ARN , Petit ARN interférent/métabolisme , Transduction du signal/effets des médicaments et des substances chimiques , Tumeurs de l'estomacRÉSUMÉ
MicroRNA regulation is crucial for gene expression and cell functions. It has been linked to tumorigenesis, development and metastasis in colorectal cancer (CRC). Recently, the let-7 family has been identified as a tumor suppressor in different types of cancers. However, the function of the let-7 family in CRC metastasis has not been fully investigated. Here, we focused on analyzing the role of let-7g in CRC. The Cancer Genome Atlas (TCGA) genomic datasets of CRC and detailed data from a Taiwanese CRC cohort were applied to study the expression pattern of let-7g. In addition, in vitro as well as in vivo studies have been performed to uncover the effects of let-7g on CRC. We found that the expression of let-7g was significantly lower in CRC specimens. Our results further supported the inhibitory effects of let-7g on CRC cell migration, invasion and extracellular calcium influx through store-operated calcium channels. We report a critical role for let-7g in the pathogenesis of CRC and suggest let-7g as a potential therapeutic target for CRC treatment.
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Helicobacter pylori has been identified as one of the major causes of chronic gastritis, gastric and duodenal ulcers, and gastric cancer. Lipopolysaccharide (LPS) is a major component of the outer membrane of gram-negative bacteria, and H. pylori LPS might play an exclusively important role in activating inflammatory pathways in monocytes and macrophages. To study the role of LPS in the underlying mechanism of inflammatory responses, we established an in vitro model using the human AGS gastric cancer cell line. We found that LPS mediates inflammation through setting off a cascade of events: activation of the store-operated calcium (SOC) channel, initiation of downstream NF-κB signaling, and phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2). Phosphorylated ERK1/2 promotes the nuclear translocation of NF-κB, and eventually elevates the expression level of COX-2, a major inflammatory gene.
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Calcium/métabolisme , Cyclooxygenase 2/génétique , Régulation de l'expression des gènes tumoraux/effets des médicaments et des substances chimiques , Lipopolysaccharides/pharmacologie , Tumeurs de l'estomac/génétique , Inhibiteurs des canaux calciques/pharmacologie , Canaux calciques/métabolisme , Lignée cellulaire tumorale , Chélateurs/pharmacologie , Cyclooxygenase 2/métabolisme , Extracellular Signal-Regulated MAP Kinases/métabolisme , Humains , Modèles biologiques , Facteur de transcription NF-kappa B/métabolisme , Nitriles/pharmacologie , Protéine ORAI1/métabolisme , Phosphorylation/effets des médicaments et des substances chimiques , Régions promotrices (génétique)/génétique , Tumeurs de l'estomac/anatomopathologie , Molécule-1 d'interaction stromale/métabolisme , Sulfones/pharmacologie , Facteurs tempsRÉSUMÉ
BACKGROUND: Anemia is common among end-stage renal disease (ESRD) patients who undergone hemodialysis. The total reduction of red blood cell (RBC) count is associated with poor prognosis in these patients. Although erythropoietin (EPO) has been used as an effective treatment for ESRD patients with anemia, a large number of patients still present poor responses to EPO treatment. METHODS: We measured T-cell receptor sequencing profiles, including length of complementarity-deteremining region 3 (CDR3), intra- and inter-group (EPO resistant vs. responsive) clonotype diversity, V(D)J usage profiles and V-J combinations from ESRD patients and to investigate the correlation between these features and EPO treatment efficacy. RESULTS: Our results revealed statistical significance in the top 3 ~ 15 most abundant joint distributions of Vß/Jß among the two groups, suggesting the importance of V or J gene utilization in the EPO response of ESRD patients. CONCLUSIONS: In summary, we provided evidence addressing the potential correlation between the immune repertoire and EPO response in ESRD patients. TRIAL REGISTRATION: TMU-JIRB 201309026. Registered 16 October 2013.
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Anémie/traitement médicamenteux , Érythropoïétine/administration et posologie , Défaillance rénale chronique/traitement médicamenteux , Adulte , Sujet âgé , Femelle , Humains , Mâle , Adulte d'âge moyen , Dialyse rénale/statistiques et données numériques , Résultat thérapeutiqueRÉSUMÉ
Dysfunctional intratumoral immune reactions are shaped by complex networks of cytokines (including chemokines), and how the cytokinome landscape coordinates with tumors has not been systematically investigated. Using high-dimensional datasets of cancer specimens, we explored the transcript abundance, biomarker potential, and prognostic impact of local cytokines across 19 tumor types. We found that most cytokines are highly locally dysregulated (p = 0.024), revealing spatiotemporal pattern of local cytokines in the development of cancers. In addition, we noted the significant downregulation of CCL14 and CXCL12 in 9 and 10 cancer types, respectively, implying their crucial roles in tumor pathogenesis. We also found that cytokines showed significantly higher specificity properties compared to other protein-coding genes (PCGs) in primary tumor specimens (p << 0.001), indicating that tissue context remains an issue when considering cancer cytokinomes. Finally, we linked concentrations of local cytokines to patient survival. Our results thus provide a panoramic view of pan-cancer cytokinomes, which highlights tumor type specificity of cancer-related cytokines and their impacts on disease prognosis.
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Triple negative breast cancer (TNBC) accounts for approximately 15-20% of all types of breast cancer, and treatment is still limited. This type of breast cancer shows a high risk of recurrence, visceral metastasis, a worse prognosis, and shorter distant metastasis-free survival. Several studies have been reported that genetics factors are associated with breast cancer disease progression and patients' survival. In this study, we combined Taiwanese microarray data from the GEO database and The Cancer Genome Atlas (TCGA) database to study the role of Integrin Beta1 (ITGB1) in TNBC. Two triple negative breast cancer cell lines (MDA-MB-231; MDA-MB-468) were used to validate the functions of ITGB1. We found that a higher ITGB1 gene expression level was associated to lower survival. Silencing of ITGB1 inhibited TNBC cell migration, invasion and store-operated calcium influx. Our study provided a potential candidate biomarker for breast cancer cells migration, invasion and TNBC patients' survival.
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Marqueurs biologiques tumoraux/génétique , Régulation de l'expression des gènes tumoraux , Antigènes CD29/génétique , Tumeurs du sein triple-négatives/génétique , Asiatiques/génétique , Calcium/métabolisme , Cycle cellulaire , Lignée cellulaire tumorale , Mouvement cellulaire , Prolifération cellulaire , Femelle , Analyse de profil d'expression de gènes , Extinction de l'expression des gènes , Humains , Antigènes CD29/métabolisme , Pronostic , ARN messager/métabolisme , Petit ARN interférent/génétique , TaïwanRÉSUMÉ
PURPOSE: Calcium signaling is an important intracellular pathway. Increased intracellular calcium is associated with cytokine regulation and inflammatory signals secretion. The purpose of this study is to understand the molecular mechanisms by which calcium signaling controls IL-8 activation in human RPE cells. METHODS: Fluorescence-based calcium imaging and different mutants of IL-8 plasmids were used in this study. The IL-8 promoter activation, gene expression, and secretion were detected by using luciferase reporter assay, quantitative real-time PCR (Q-PCR), and ELISA, respectively. In addition, pharmacological inhibitors and small interfering RNA (siRNA) were applied to clarify the mechanisms of IL-8 activation. RESULTS: Our study reported that intracellular calcium mobilization activated IL-8 gene expression and secretion. Application of pharmacological inhibitor BAY 11-7082, siRNA, and plasmids of the nuclear factor κ light chain enhancer of activated B cells (NF-κB) binding site, we identified that NF-κB is the main transcription factor involved in intracellular calcium mobilization-mediated IL-8 activation in human RPE cells. CONCLUSIONS: Collectively, our findings highlight the important role of intracellular calcium mobilization in the activation of IL-8. These findings may be helpful for the clinical applications in the age-related macular degeneration (AMD) prevention and treatment.
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Calcium/métabolisme , Régulation de l'expression des gènes , Interleukine-8/génétique , Dégénérescence maculaire/métabolisme , ARN/génétique , Épithélium pigmentaire de la rétine/métabolisme , Technique de Western , Signalisation calcique , Cellules cultivées , Test ELISA , Humains , Interleukine-8/biosynthèse , Dégénérescence maculaire/anatomopathologie , ARN/métabolisme , Réaction de polymérisation en chaine en temps réel , Épithélium pigmentaire de la rétine/anatomopathologieRÉSUMÉ
Divalent lead (Pb(2+) ) is a common industrial pollutant epidemiologically associated with gastric cancers. Pb(2+) was found to promote tumorigenesis, which may include interleukin (IL)-8, a pro-inflammatory chemokine that promotes angiogenesis and tumor metastasis. Given that the gastrointestinal tract is a major route of Pb(2+) exposure, we investigated the ability of Pb(2+) to induce IL-8 expression in gastric carcinoma cells and its underlying mechanism. At a concentration of 0.1 µM, Pb(2+) induced IL-8 gene activation in gastric carcinoma AGS cells. Using a IL-8 promoter-deletion analysis, transcription factor activator protein 1 (AP-1) was identified as a necessary component of Pb(2+) -induced IL-8 gene activation. Upregulation of the IL-8 gene was abrogated by the MEK inhibitor, PD98059, and partially suppressed by the epidermal growth factor receptor inhibitors, AG1478 and PD153035. Furthermore, c-Jun protein expression was induced in cells treated with Pb(2+) , and overexpression of c-Jun enhanced Pb(2+) -induced IL-8 activation. Collectively, our findings highlight the pivotal roles of AP-1 and extracellular signal-regulated kinase in signal transduction of Pb(2+) -induced IL-8 gene activation. These molecules may be potential therapeutic targets for Pb(2+) -related inflammation leading to stomach carcinogenesis. © 2013 Wiley Periodicals, Inc. Environ Toxicol 30: 315-322, 2015.
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Polluants environnementaux/toxicité , Extracellular Signal-Regulated MAP Kinases/métabolisme , Interleukine-8/biosynthèse , Interleukine-8/génétique , Plomb/toxicité , Tumeurs de l'estomac/métabolisme , Facteur de transcription AP-1/métabolisme , Lignée cellulaire tumorale , Antienzymes/pharmacologie , Récepteurs ErbB/antagonistes et inhibiteurs , Extracellular Signal-Regulated MAP Kinases/antagonistes et inhibiteurs , Flavonoïdes/pharmacologie , Humains , Protéines proto-oncogènes c-jun/biosynthèse , Quinazolines/pharmacologie , Tyrphostines/pharmacologie , Régulation positive/effets des médicaments et des substances chimiquesRÉSUMÉ
Lead ions (Pb(2+) ) are toxic industrial pollutants associated with chronic inflammatory diseases in humans and animals. Previously, we found that Pb(2+) ions induce COX-2 gene expression via the EGF receptor/nuclear factor-κB signal transduction pathway in epidermoid carcinoma cell line A431. In this study, to see whether Pb(2+) ions affect COX-2 expression by epigenetic mechanisms, we looked at the mRNAs of DNA methyltransferases (DNMTs) using real-time PCR of total RNA from these cells. Cells exposed to Pb(2+) had low levels of DNMT3a mRNA, whereas the levels of DNMT1 and DNMT3b mRNAs remained unchanged. Pretreatment of cells with DNMT inhibitor 5-aza-2'-deoxycytidine (5 µM) followed by Pb(2+) (1 µM) significantly increased levels of COX-2 mRNA compared with cells treated with Pb(2+) alone. Overexpression of tumor suppressor gene Rb correlated with an increase in COX-2 mRNA and a decrease in DNMT3a mRNA. Conversely, overexpression of transcription factor E2F1 correlated with a decrease in COX-2 mRNA and an increase in DMNT3a mRNA. Pretreatment with EGFR inhibitors AG1478 and PD153035 significantly limited Pb(2+) -induced reduction in DNMT3a mRNA. In addition, gene knockdown of DNMT3a with short hairpin RNA correlated with increased COX-2 mRNA induced by Pb(2+) . Our findings suggest Pb(2+) ions induce COX-2 expression indirectly by reducing DNMT3a methylation of the COX-2 promoter via transcription factors Rb and E2F1.