RESUMEN
Lung cancer is among the most aggressive types of malignant tumors that contributes to cancer-associated deaths worldwide with a high occurrence and fatality rate. Histone deacetylase 2 (HDAC2), prevent the aberrant transcription of a number of genes that are primarily responsible for controlling the cell cycle, cell proliferation, and signaling pathways in numerous cancers. Previous studies reported the role of HDACs and YY1 in the growth and development of several cancers. Although, it is noteworthy that remarkable efforts have been taken for the treatment of lung cancer using molecularly targeted therapies and chemotherapeutic agents, but the outcome is still poor for this critically persistent cancer. Therefore, the aim of the present study is to identify an efficacious, novel therapeutic biomarkers for the successful diagnosis of lung cancer at the early stage of the disease and the molecular insights involved. In the present study, qPCR and western bot data revealed that the expression level of HDAC2 and YY1 were upregulated in the cell lines and tumor samples of lung cancer patients. Moreover, MTT, qPCR, western blot, cell cycle analysis, and migration assays showed that inhibition of HDAC2 reduced YY1 expression, similarly, depletion of YY1 using knockdown approach inhibited the proliferation, migration, invasion, and blockage of the cell cycle by suppressing c-Myc in lung cancer cell lines. In conclusion, the current study findings support the notion that HDAC2's anticancer role was attributed through YY1 regulation by targeting c-Myc and could act as potential novel candidate biomarker for the lung cancer diagnosis.
Asunto(s)
Neoplasias Pulmonares , MicroARNs , Humanos , MicroARNs/genética , Proteínas Proto-Oncogénicas c-myc/genética , Proteínas Proto-Oncogénicas c-myc/metabolismo , Línea Celular Tumoral , Histona Desacetilasa 2/genética , Histona Desacetilasa 2/metabolismo , Transducción de Señal , Neoplasias Pulmonares/patología , Proliferación Celular/genética , Movimiento Celular/genética , Regulación Neoplásica de la Expresión Génica , Factor de Transcripción YY1/genética , Factor de Transcripción YY1/metabolismoRESUMEN
INTRODUCTION: Selenium (Se) as well as selenoproteins are vital for osteochondral system development. Se deficiency (SeD) has a definite impact on the expression and activity of histone deacetylases (HDACs). Abnormal expression of some HDACs affects cartilage development. This current study aims to explore the relationship between differentially expressed HDACs and cartilage development, especially extracellular matrix (ECM) homeostasis maintenance, under SeD conditions. MATERIALS AND METHODS: Dark Agouti rats and C28/I2 cell line under SeD states were used to detect the differently expressed HDAC by RT-qPCR, western blotting and IHC staining. Meanwhile, the biological roles of the above HDAC in cartilage development and homeostasis maintenance were confirmed by siRNA transfection, western blotting, RNA sequence and inhibitor treatment experiments. RESULTS: HDAC2 exhibited lower expression at protein level in both animals and chondrocytes during SeD condition. The results of cell-level experiments indicated that forkhead box O3A (FOXO3A), which was required to maintain metabolic homeostasis of cartilage matrix, was reduced by HDAC2 knockdown. Meanwhile, induced HDAC2 was positively associated with FOXO3A in rat SeD model. Meanwhile, knockdown of HDAC2 and FOXO3A led to an increase of intracellular ROS level, which activated NF-κB pathway. Se supplementary significantly inhibited the activation of NF-κB pathway with IL-1ß treatment. CONCLUSION: Our results suggested that low expression of HDAC2 under SeD condition increased ROS content by decreasing FOXO3A in chondrocytes, which led to the activation of NF-κB pathway and ECM homeostasis imbalance.
Asunto(s)
Proteína Forkhead Box O3 , Histona Desacetilasa 2 , Selenio , Animales , Ratas , Cartílago , Matriz Extracelular , Histona Desacetilasa 2/genética , FN-kappa B , Especies Reactivas de Oxígeno , Selenio/farmacología , Proteína Forkhead Box O3/genéticaRESUMEN
BACKGROUND: Tyrosine kinase inhibitors (TKIs) such as sunitinib are multitarget antiangiogenic agents in clear cell renal cell carcinoma (ccRCC). They are widely used in the treatment of advanced/metastatic renal cancer. However, resistance to TKIs is common in the clinic, particularly after long-term treatment. YTHDC1 is the main nuclear reader protein that binds with m6A to regulate the splicing, export and stability of mRNA. However, the specific role and corresponding mechanism of YTHDC1 in renal cancer cells are still unclear. METHODS: The Cancer Genome Atlas (TCGA) dataset was used to study the expression of YTHDC1 in ccRCC. Cell counting kit-8 (CCK-8), wound healing, Transwell and xenograft assays were applied to explore the biological function of YTHDC1 in ccRCC. Western blot, quantitative real time PCR (RTâqPCR), RNA immunoprecipitation PCR (RIP-qPCR), methylated RIP-qPCR (MeRIP-qPCR) and RNA sequencing (RNA-seq) analyses were applied to study the YY1/HDAC2/YTHDC1/ANXA1 axis in renal cancer cells. The CCK-8 assay and xenograft assay were used to study the role of YTHDC1 in determining the sensitivity of ccRCC to sunitinib. RESULTS: Our results demonstrated that YTHDC1 is downregulated in ccRCC tissues compared with normal tissues. Low expression of YTHDC1 is associated with a poor prognosis in patients with ccRCC. Subsequently, we showed that YTHDC1 inhibits the progression of renal cancer cells via downregulation of the ANXA1/MAPK pathways. Moreover, we also showed that the YTHDC1/ANXA1 axis modulates the sensitivity of tyrosine kinase inhibitors. We then revealed that HDAC2 inhibitors resensitize ccRCC to tyrosine kinase inhibitors through the YY1/HDAC2 complex. We have identified a novel YY1/HDAC2/YTHDC1/ANXA1 axis modulating the progression and chemosensitivity of ccRCC. CONCLUSION: We identified a novel YY1/HDAC2/YTHDC1/ANXA1 axis modulating the progression and chemosensitivity of ccRCC.
Asunto(s)
Carcinoma de Células Renales , Neoplasias Renales , Proteínas del Tejido Nervioso , Factores de Empalme de ARN , Anexina A1/genética , Anexina A1/metabolismo , Carcinoma de Células Renales/tratamiento farmacológico , Carcinoma de Células Renales/genética , Carcinoma de Células Renales/metabolismo , Línea Celular Tumoral , Proliferación Celular/genética , Histona Desacetilasa 2/genética , Histona Desacetilasa 2/metabolismo , Humanos , Neoplasias Renales/tratamiento farmacológico , Neoplasias Renales/genética , Neoplasias Renales/metabolismo , Sistema de Señalización de MAP Quinasas , Proteínas del Tejido Nervioso/genética , Proteínas del Tejido Nervioso/metabolismo , Inhibidores de Proteínas Quinasas , Factores de Empalme de ARN/genética , Factores de Empalme de ARN/metabolismo , Sunitinib/farmacología , Factor de Transcripción YY1/genética , Factor de Transcripción YY1/metabolismoRESUMEN
Nuclear deformation is an essential phenomenon allowing cell migration and can be observed in association with pathological conditions such as laminopathies, neurodegenerative disorders and diabetes. Abnormal nuclear morphologies are a hallmark of cancer progression and nuclear deformability is a necessary feature for metastatic progression. Nevertheless, the cellular processes and the key molecular components controlling nuclear shape are poorly understood, in part due to a limited availability of assays that allow high-throughput screening of nuclear morphology-phenotypes. In this study, we explore the application of micropillared substrates as the basis for a phenotypic screening platform aimed at identifying novel determinants of nuclear morphology. We designed PDMS substrates to maximize simplicity in image acquisition and analyses, and in a small-scale screening of inhibitors targeting chromatin-modifying enzymes, we identify histone deacetylation as cellular process involved in nuclear deformation. With increasingly specific targeting approaches, we identify HDAC2 as a novel player in controlling nuclear morphology through gene transcription repression. This study shows the effectiveness of micropillar-based substrates to act as phenotypic drug screening platforms and opens a new avenue in the identification of genes involved in determining the nuclear shape.
Asunto(s)
Histona Desacetilasa 2 , Neoplasias , Cromatina/genética , Cromatina/metabolismo , Evaluación Preclínica de Medicamentos , Histona Desacetilasa 2/genética , Histona Desacetilasa 2/metabolismo , Humanos , FenotipoRESUMEN
Green tea polyphenols (GTPs) are regarded as anticancer substances and have been revealed to play significant roles in the development of malignant melanoma. However, the mechanisms by which GTPs perform anticarcinogenic activity are not well elucidated. Cellular function assays revealed that GTPs inhibited melanoma cell proliferation, migration, invasion, epithelial-mesenchymal transition (EMT), and promoted apoptosis in vitro. Circ_MITF expression was elevated in melanoma tissues and cells but was decreased by GTPs in cells. Functional experiments indicated circ_MITF overexpression reversed the anticancer effects of GTPs on melanoma cells. Then the underlying mechanism analysis suggested that circ_MITF served as a sponge for miR-30e-3p to upregulate the level of HDAC2. MiR-30e-3p reexpression attenuated the regulatory effects of circ_MITF on GTPs-treated melanoma cells. Silencing of miR-30e-3p promoted the malignant phenotypes in GTPs-treated melanoma cells, which were reversed by HDAC2 knockdown. Preclinically, administration of GTPs suppressed the expression of downstream target genes and repressed tumorigenesis of xenografts in nude mice. In all, GTPs suppressed melanoma progression by regulating circ_MITF/miR-30e-3p/HDAC2 axis, providing a potential therapeutic strategy for human malignant melanoma intervention.
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Melanoma , MicroARNs , Animales , Proliferación Celular/genética , Histona Desacetilasa 2/genética , Humanos , Melanoma/tratamiento farmacológico , Ratones , Ratones Desnudos , MicroARNs/genética , MicroARNs/metabolismo , Factor de Transcripción Asociado a Microftalmía , Polifenoles/farmacología , ARN Circular , Neoplasias Cutáneas , Té , Melanoma Cutáneo MalignoRESUMEN
Aberrant epigenetic modifications are responsible for tumor development and cancer progression; however, readily reversible. Bioactive molecules from diets are promising to cure cancer by modulating epigenetic marks and changing immune response. These compounds specifically target the activity of DNMTs and HDACs to cure various human cancers. In view of this, we investigated the anticancer and epigenetic regulatory activities of an edible-plant Paederia foetida. The efficacy of methanolic extract of P. foetida leaves (MEPL) was tested for the modulation of epigenetic factors in gene silencing, i.e. DNMT and HDAC and expression pattern of certain tumor-suppressor genes. After treatment of prostate cancer cells (PC-3 and DU-145) with MEPL, lupeol and ß-sitosterol; induction of apoptosis, decrease in cellular-viability and inhibition of cellular-migration were noticed. Simultaneously there was inhibition of DNMT1, HDACs and pro-inflammatory, IL-6, IL1-ß, TNF-α and anti-inflammatory, IL-10 genes in cancer and THP1 cell lines. The DNMT1 protein content, enzyme activity and Bcl2 expression decreased significantly; however, expression of E-cadherin (CDH1) and pro-apoptotic gene Bax increased significantly after the treatment of cells with drugs. We conclude plant-derived compounds can be considered to target epigenetic machineries involved with malignant transformation and can open new avenues for cancer therapeutics provoking immune response.
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Supervivencia Celular/efectos de los fármacos , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Inflamación/metabolismo , Extractos Vegetales/farmacología , Neoplasias de la Próstata , Rubiaceae/química , Línea Celular Tumoral , ADN (Citosina-5-)-Metiltransferasa 1/genética , ADN (Citosina-5-)-Metiltransferasa 1/metabolismo , Histona Desacetilasa 1/genética , Histona Desacetilasa 1/metabolismo , Histona Desacetilasa 2/genética , Histona Desacetilasa 2/metabolismo , Humanos , Inflamación/genética , Masculino , Triterpenos Pentacíclicos , Fitoquímicos , Extractos Vegetales/química , Hojas de la Planta/química , ARN Mensajero/genética , ARN Mensajero/metabolismo , SitoesterolesRESUMEN
The biological role of miR-500a-5p has not yet been reported in the context of colorectal cancer (CRC). Here, we show that miR-500a-5p expression is decreased in CRC tissues compared with adjacent normal tissues. Low miR-500a-5p expression is associated with malignant progression. Moreover, transfection of CRC cells with miR-500a-5p induces G0/G1 cell cycle arrest and inhibits their growth and migration. Mechanistically, miR-500a-5p directly targets HDAC2 and inhibits HDAC2-mediated proliferation in CRC in nude mice. Furthermore, YY1 binds to the promoter of miR-500a-5p and negatively regulates its transcription. Restoration of miR-500a-5p expression is up-regulated via the p300/YY1/HDAC2 complex. Besides, therapeutic delivery of miR-500a-5p significantly suppresses tumour development in a xenograft tumour model and a HDAC2 inhibitor FK228-treated CRC model. Our studies demonstrate that miR-500a-5p functions as a tumour suppressor in CRC by targeting the p300/YY1/HDAC2 axis, which contributes to the development of and provides new potential candidates for CRC therapy.
Asunto(s)
Neoplasias Colorrectales/metabolismo , Proteína p300 Asociada a E1A/metabolismo , Histona Desacetilasa 2/metabolismo , MicroARNs/metabolismo , Factor de Transcripción YY1/metabolismo , Animales , Apoptosis/genética , Apoptosis/fisiología , Línea Celular , Línea Celular Tumoral , Proliferación Celular/genética , Proliferación Celular/fisiología , Neoplasias Colorrectales/genética , Proteína p300 Asociada a E1A/genética , Femenino , Regulación Neoplásica de la Expresión Génica/genética , Regulación Neoplásica de la Expresión Génica/fisiología , Células HCT116 , Histona Desacetilasa 2/genética , Humanos , Etiquetado Corte-Fin in Situ , Ratones , Ratones Endogámicos BALB C , Ratones Desnudos , MicroARNs/genética , Transducción de Señal/genética , Transducción de Señal/fisiología , Factor de Transcripción YY1/genéticaRESUMEN
Rosmarinic acid (RA), a main phenolic compound contained in rosemary which is used as tea, oil, medicine and so on, has been known to present anti-inflammatory, anti-oxidant and anti-cancer effects. Histone deacetylases (HDACs) are enzymes that play important roles in gene expression by removing the acetyl group from histone. The aberrant expression of HDAC in human tumors is related with the onset of human cancer. Especially, HDAC2, which belongs to HDAC class I composed of HDAC 1, 2, 3 and 8, has been reported to be highly expressed in prostate cancer (PCa) where it downregulates the expression of p53, resulting in an inhibition of apoptosis. The purpose of this study is to investigate the effect of RA in comparison with suberoylanilide hydroxamic acid (SAHA), an HDAC inhibitor used as an anti-cancer agent, on survival and apoptosis of PCa cell lines, PC-3 and DU145, and the expression of HDAC. RA decreased the cell proliferation in cell viability assay, and inhibited the colony formation and tumor spheroid formation. Additionally, RA induced early- and late-stage apoptosis of PC-3 and DU145 cells in Annexin V assay and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay, respectively. In western blot analysis, RA inhibited the expression of HDAC2, as SAHA did. Proliferating cell nuclear antigen (PCNA), cyclin D1 and cyclin E1 were downregulated by RA, whereas p21 was upregulated. In addition, RA modulated the protein expression of intrinsic mitochondrial apoptotic pathway-related genes, such as Bax, Bcl-2, caspase-3 and poly (ADP-ribose) polymerase 1 (PARP-1) (cleaved) via the upregulation of p53 derived from HDAC2 downregulation, leading to the increased apoptosis of PC-3 and DU145 cells. Taken together, treatment of RA to PCa cell lines inhibits the cell survival and induces cell apoptosis, and it can be used as a novel therapeutic agent toward PCa.
Asunto(s)
Apoptosis/efectos de los fármacos , Puntos de Control del Ciclo Celular/efectos de los fármacos , Cinamatos/análisis , Depsidos/análisis , Histona Desacetilasa 2/metabolismo , Rosmarinus/química , Anexina A5 , Caspasa 3/genética , Caspasa 3/metabolismo , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Ciclina D1/genética , Ciclina D1/metabolismo , Ciclina E/genética , Ciclina E/metabolismo , Fragmentación del ADN/efectos de los fármacos , Regulación de la Expresión Génica , Histona Desacetilasa 2/genética , Inhibidores de Histona Desacetilasas/farmacología , Histona Desacetilasas/metabolismo , Humanos , Etiquetado Corte-Fin in Situ , Masculino , Proteínas Oncogénicas/genética , Proteínas Oncogénicas/metabolismo , Poli(ADP-Ribosa) Polimerasa-1/genética , Poli(ADP-Ribosa) Polimerasa-1/metabolismo , Antígeno Nuclear de Célula en Proliferación/genética , Antígeno Nuclear de Célula en Proliferación/metabolismo , Neoplasias de la Próstata/metabolismo , Transducción de Señal , Tés de Hierbas , Tés Medicinales , Vorinostat/análisis , Proteína X Asociada a bcl-2/genética , Proteína X Asociada a bcl-2/metabolismo , Ácido RosmarínicoRESUMEN
SCOPE: Histone deacetylases (HDACs) have emerged as epigenetic regulators of risk factors associated with the metabolic syndrome (MetS), and certain botanical extracts have proven to be potent HDAC inhibitors. Understanding the role of dietary procyanidins in HDAC inhibition is important in exploring the therapeutic potential of natural products. METHODS: C57BL/6 mice were gavaged with vehicle (water) or grape seed procyanidin extract (GSPE, 250 mg/kg) and terminated 14 h later. Liver and serum were harvested to assess the effect of GSPE on HDAC activity, histone acetylation, Pparα activity and target-gene expression, and serum lipid levels. RESULTS: GSPE increased histone acetylation and decreased Class I HDAC activity in vivo, and dose-dependently inhibited recombinant HDAC2 and 3 activities in vitro. Accordingly, Pparα gene and phosphorylated protein expression were increased, as were target genes involved in fatty acid catabolism, suggesting increased Pparα activity. Serum fibroblast growth factor 21 (Fgf21) was elevated, and triglyceride levels were reduced by 28%. CONCLUSION: GSPE regulates HDAC and Pparα activities to modulate lipid catabolism and reduce serum triglycerides in vivo.
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Biflavonoides/farmacología , Catequina/farmacología , Extracto de Semillas de Uva/farmacología , Inhibidores de Histona Desacetilasas/farmacología , PPAR alfa/metabolismo , Proantocianidinas/farmacología , Acetilación/efectos de los fármacos , Animales , Apolipoproteína A-V/genética , Relación Dosis-Respuesta a Droga , Factores de Crecimiento de Fibroblastos/sangre , Factores de Crecimiento de Fibroblastos/genética , Extracto de Semillas de Uva/administración & dosificación , Extracto de Semillas de Uva/química , Histona Desacetilasa 2/antagonistas & inhibidores , Histona Desacetilasa 2/genética , Histona Desacetilasa 2/metabolismo , Histona Desacetilasas/metabolismo , Histonas/metabolismo , Metabolismo de los Lípidos/efectos de los fármacos , Hígado/efectos de los fármacos , Hígado/metabolismo , Masculino , Ratones Endogámicos C57BL , Fosforilación/efectos de los fármacos , Triglicéridos/sangreRESUMEN
BACKGROUND: Neutrophil-predominant asthma is less responsive to steroids and associated with poorer disease control. The effects of Antiasthma Simplified Herbal Medicine Intervention (ASHMI), a traditional Chinese medicine formula reported to be efficacious in asthmatic patients and murine asthma models, on neutrophil predominant asthma are unknown. OBJECTIVE: To determine the effects of standard ASHMI and refined formula ASHMI (ASHMI(II)) in a neutrophil-predominant murine model of ragweed (RW) asthma and explore underlying mechanisms. METHODS: BALB/c mice were systemically sensitized, intranasally challenged with RW extract, and orally treated with ASHMI, ASHMI(II), or vehicle (water). In a separate experiment, some RW sensitized mice were treated with dexamethasone before challenge. After RW challenge, airway hyperreactivity (AHR), total and differential bronchoalveolar lavage fluid leukocyte counts, lung histologic features, and bronchoalveolar lavage fluid cytokine and chemokine levels were assessed. RW stimulation of the murine macrophage cell line RAW264.7 was used to determine effects of ASHMI active compound ganoderic acid C1 (GAC1) on tumor necrosis factor α (TNF-α) production and regulation of phosphorylated IκB and histone deacetylase 2 (HDAC2) levels. RESULTS: ASHMI and ASHMI(II) markedly reduced AHR, mucous production, neutrophilic inflammation, and TNF-α, interleukin 8, and interleukin 17 levels and decreased eosinophilic inflammation and TH2 responses in vivo (P < .01-.001 for all). GAC1 inhibited TNF-α production in RW-stimulated RAW264.7 cells in association with suppression of phosphorylated IκB and increased HDAC2 expression. Dexamethasone failed to reduce AHR and neutrophilic inflammation. CONCLUSION: ASHMI treatment was efficacious in a murine model of neutrophil-predominant asthma via modulation of innate chemokines, TH2 responses, nuclear factor-κB, and HDAC2. ASHMI, and/or its constituent GAC1, may be a valuable option for treating neutrophil-predominant asthma.
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Ambrosia/efectos adversos , Asma/terapia , Medicamentos Herbarios Chinos/administración & dosificación , Macrófagos/efectos de los fármacos , Neutrófilos/efectos de los fármacos , Neumonía/terapia , Administración Oral , Alérgenos/inmunología , Animales , Antígenos de Plantas/inmunología , Línea Celular , Modelos Animales de Enfermedad , Regulación de la Expresión Génica/efectos de los fármacos , Histona Desacetilasa 2/genética , Histona Desacetilasa 2/metabolismo , Humanos , Proteínas I-kappa B/metabolismo , Recuento de Leucocitos , Macrófagos/inmunología , Ratones , Ratones Endogámicos BALB C , Neutrófilos/inmunología , Triterpenos/farmacología , Factor de Necrosis Tumoral alfa/metabolismoRESUMEN
BACKGROUND & AIMS: Gender influences incidence, progression, and therapy of hepatogastrointestinal diseases. The aim of this study was to elucidate the molecular mechanism of gender-specific UDP-glucuronosyltransferases (UGT1A) regulation, representing important hepatogastrointestinal detoxification enzymes for xenobiotics, drugs, and endobiotics. METHODS: UGT1A-gene activation was studied by reporter gene experiments and estrogen receptor alpha (ESR1/ERα) co-transfection using KYSE70- and HepG2 cells (male origin), and SW403 cells (female origin). Cell lines, and humanized transgenic UGT1A (htgUGT1A) mice (female/male) were treated with the ERα inhibitor tamoxifen. UGT1A mRNA expression was analyzed by TaqMan PCR, the recruitment of ERα, histone deacetylases (HDAC), and the aryl hydrocarbon receptor (AhR) by chromatin immunoprecipitation (ChIP), and ERα expression in gastrointestinal mouse tissues by Western blot and immunofluorescence. RESULTS: In KYSE70 cells (male), UGT1A gene expression was induced 5-10 fold, and inhibited in the presence of ERα by 55-77%. In SW403 (female) cells, absent inducibility was restored after tamoxifen treatment. In the jejunum and colon of tgUGT1A mice, UGT1A induction that was exclusively detected in male mice could be restored in female mice after tamoxifen pre-treatment. ChIP assays demonstrated the recruitment of ERα and HDACs to the xenobiotic response elements of UGT1A promoters during gene repression. Western blot showed higher ERα expression in the female jejunum and colon. CONCLUSIONS: We show gender-specific transcriptional control of UGT1A genes in jejunum and colon, which is repressed by ERα and the recruitment of HDCAs to the UGT1A promoter sequence in females. A molecular mechanism controlling gender-specific drug metabolism and its therapeutic reversal is demonstrated.
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Receptor alfa de Estrógeno/metabolismo , Glucuronosiltransferasa/genética , Histona Desacetilasa 1/metabolismo , Histona Desacetilasa 2/metabolismo , Animales , Línea Celular , Café , Colon/metabolismo , Receptor alfa de Estrógeno/genética , Femenino , Regulación Enzimológica de la Expresión Génica/efectos de los fármacos , Células Hep G2 , Histona Desacetilasa 1/genética , Histona Desacetilasa 2/genética , Humanos , Yeyuno/metabolismo , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Regiones Promotoras Genéticas , ARN Mensajero/genética , ARN Mensajero/metabolismo , Receptores de Hidrocarburo de Aril/metabolismo , Moduladores Selectivos de los Receptores de Estrógeno/farmacología , Caracteres Sexuales , Tamoxifeno/farmacologíaRESUMEN
The serotonin (5-HT) transporter (SERT) facilitates clearance of extracellular 5-HT by its uptake and internalization. Decreased expression of SERT and consequent high 5-HT levels have been implicated in various diarrheal disorders. Thus, appropriate regulation of SERT is critical for maintenance of 5-HT homeostasis in health and disease. Previous studies demonstrated that SERT is regulated via posttranslational and transcriptional mechanisms. However, the role of epigenetic mechanisms in SERT regulation is not known. Current studies investigated the effects of histone deacetylase (HDAC) inhibition on SERT expression and delineated the mechanisms. Treatment of Caco-2 cells with the pan-HDAC inhibitors butyrate (5 mM) and trichostatin (TSA, 1 µM) decreased SERT mRNA and protein levels. Butyrate- or TSA-induced decrease in SERT was associated with decreased activity of human SERT (hSERT) promoter 1 (upstream of exon 1a), but not hSERT promoter 2 (upstream of exon 2). Butyrate + TSA did not show an additive effect on SERT expression, indicating that mechanisms involving histone hyperacetylation may be involved. Chromatin immunoprecipitation assays demonstrated enrichment of the hSERT promoter 1 (flanking nt -250/+2) with tetra-acetylated histone H3 or H4, which was increased (~3-fold) by butyrate. Interestingly, specific inhibition of HDAC2 (but not HDAC1) utilizing small interfering RNA decreased SERT mRNA and protein levels. The decrease in SERT expression by HDAC inhibition was recapitulated in an in vivo model. SERT mRNA levels were decreased in the ileum and colon of mice fed pectin (increased availability of butyrate) compared with controls fed a fiber-free diet (~50-60%). Our results identify a novel role of HDAC2 as a regulator of SERT gene expression in intestinal epithelial cells.