deoxycholic-acid and Barrett-Esophagus

Hydrophobic bile acids like deoxycholic acid (DCA), which cause oxidative DNA damage and activate NF-κB in Barrett's metaplasia, might contribute to carcinogenesis in Barrett's esophagus. We have explored mechanisms whereby ursodeoxycholic acid (UDCA, a hydrophilic bile acid) protects against DCA-induced injury in vivo in patients and in vitro using nonneoplastic, telomerase-immortalized Barrett's cell lines. We took biopsies of Barrett's esophagus from 21 patients before and after esophageal perfusion with DCA (250 μM) at baseline and after 8 wk of oral UDCA treatment. DNA damage was assessed by phospho-H2AX expression, neutral CometAssay, and phospho-H2AX nuclear foci formation. Quantitative PCR was performed for antioxidants including catalase and GPX1. Nrf2, catalase, and GPX1 were knocked down with siRNAs. Reporter assays were performed using a plasmid construct containing antioxidant responsive element. In patients, baseline esophageal perfusion with DCA significantly increased phospho-H2AX and phospho-p65 in Barrett's metaplasia. Oral UDCA increased GPX1 and catalase levels in Barrett's metaplasia and prevented DCA perfusion from inducing DNA damage and NF-κB activation. In cells, DCA-induced DNA damage and NF-κB activation was prevented by 24-h pretreatment with UDCA, but not by mixing UDCA with DCA. UDCA activated Nrf2 signaling to increase GPX1 and catalase expression, and protective effects of UDCA pretreatment were blocked by siRNA knockdown of these antioxidants. UDCA increases expression of antioxidants that prevent toxic bile acids from causing DNA damage and NF-κB activation in Barrett's metaplasia. Elucidation of this molecular pathway for UDCA protection provides rationale for clinical trials on UDCA for chemoprevention in Barrett's esophagus.

Topics: Adult; Aged; Aged, 80 and over; Anticarcinogenic Agents; Antioxidants; Barrett Esophagus; Catalase; Cell Line; Deoxycholic Acid; DNA Damage; Epithelial Cells; Esophageal Neoplasms; Esophagus; Female; Glutathione Peroxidase; Glutathione Peroxidase GPX1; Histones; Humans; Male; Middle Aged; NF-E2-Related Factor 2; Phosphorylation; RNA Interference; RNA, Messenger; Time Factors; Transcription Factor RelA; Transfection; Treatment Outcome; Up-Regulation; Ursodeoxycholic Acid

Dysregulation of toll-like receptor (TLR) signaling within the gastrointestinal epithelium has been associated with uncontrolled inflammation and tumorigenesis. We sought to evaluate the role of TLR4 in the development of gastroesophageal reflux-mediated inflammation and mucosal changes of the distal esophagus. Verified human esophageal Barrett's cells with high grade dysplasia (CPB) and esophageal adenocarcinoma cells (OE33) were treated with deoxycholic acid for 24 hours. Cells were pretreated with a TLR4-specific inhibitor peptide 2 hours prior to deoxycholic acid treatment. Inflammatory markers were evaluated using immunoblotting and enzyme-linked immunosorbent assay. A surgical reflux mouse model was generated by performing a side-to-side anastomosis between the second portion of the duodenum and the gastroesophageal junction. Control animals underwent laparotomy with incision and closure of the esophagus superior to the gastroesophageal junction (sham procedure). Esophageal sections were evaluated using hematoxylin and eosin staining and immunohistochemistry. Deoxycholic acid increased expression of inflammatory markers including intercellular adhesion molecule-1, vascular cell adhesion molecule-1, and interleukin 8. Pretreatment with a TLR4 inhibitor significantly decreased deoxycholic acid-induced inflammatory marker expression. C3H/HeNCrl mice demonstrated a significant increase in mucosal hyperplasia and proliferation following DGEA compared to sham procedure. TLR4 mutant mice (C3H/HeJ) undergoing DGEA demonstrated an attenuated hyperplastic and proliferative response compared to C3H/HeNCrl mice. Inhibition of TLR4 signaling attenuates reflux-induced inflammation in vivo. These findings identify TLR4 inhibition as a potential therapeutic target to halt the progression of pathologic esophageal changes developing in the setting of chronic gastroesophageal reflux disease.

Topics: Animals; Barrett Esophagus; Deoxycholic Acid; Esophageal Neoplasms; Gastroesophageal Reflux; Humans; Inflammation; Mice; Mice, Inbred C3H; Toll-Like Receptor 4; Treatment Outcome

Obesity is a known risk factor for the development of gastroesophageal reflux disease (GERD), Barrett's Esophagus (BE) and the progression to esophageal adenocarcinoma. The mechanisms by which obesity contributes to GERD, BE and its progression are currently not well understood. Recently, changes in lipid metabolism especially in the context of a high fat diet have been linked to GERD and BE leading us to explore whether fatty acid oxidation plays a role in the disease progression from GERD to esophageal adenocarcinoma. To that end, we analyzed the expression of the rate-limiting enzyme, carnitine palmytoyltransferase 1A (CPT1A), in human tissues and cell lines representing different stages in the sequence from normal squamous esophagus to cancer. We determined uptake of palmitic acid, the most abundant fatty acid in human serum, with fluorescent dye-labeled lipids as well as functional consequences of stimulation with palmitic acid relevant to Barrett's tumorigenesis, e.g., proliferation, characteristics of stemness and IL8 mediated inflammatory signaling. We further employed different mouse models including a genetic model of Barrett's esophagus based on IL1β overexpression in the presence and absence of a high fat diet and deoxycholic acid to physiologically mimic gastrointestinal reflux in the mice. Together, our data demonstrate that CPT1A is upregulated in Barrett's tumorigenesis and that experimental palmitic acid is delivered to mitochondria and associated with increased cell proliferation and stem cell marker expression.

Topics: Adenocarcinoma; Animals; Barrett Esophagus; Carcinogenesis; Carnitine; Carnitine O-Palmitoyltransferase; Cell Proliferation; Cell Transformation, Neoplastic; Deoxycholic Acid; Esophageal Neoplasms; Fluorescent Dyes; Gastroesophageal Reflux; Humans; Interleukin-8; Mice; Obesity; Palmitic Acid

The bile acid component of gastric refluxate has been implicated in inflammation of the oesophagus including conditions such as gastro-oesophageal reflux disease (GORD) and Barrett's Oesophagus (BO). Here we demonstrate that the hydrophobic bile acid, deoxycholic acid (DCA), stimulated the production of IL-6 and IL-8 mRNA and protein in Het-1A, a model of normal oesophageal cells. DCA-induced production of IL-6 and IL-8 was attenuated by pharmacologic inhibition of the Protein Kinase C (PKC), MAP kinase, tyrosine kinase pathways, by the cholesterol sequestering agent, methyl-beta-cyclodextrin (MCD) and by the hydrophilic bile acid, ursodeoxycholic acid (UDCA). The cholesterol-interacting agent, nystatin, which binds cholesterol without removing it from the membrane, synergized with DCA to induce IL-6 and IL-8. This was inhibited by the tyrosine kinase inhibitor genistein. DCA stimulated the phosphorylation of lipid raft component Src tyrosine kinase (Src). while knockdown of caveolin-1 expression using siRNA resulted in a decreased level of IL-8 production in response to DCA. Taken together, these results demonstrate that DCA stimulates IL-6 and IL-8 production in oesophageal cells via lipid raft-associated signaling. Inhibition of this process using cyclodextrins represents a novel therapeutic approach to the treatment of inflammatory diseases of the oesophagus including GORD and BO.

Topics: Barrett Esophagus; beta-Cyclodextrins; Bile Acids and Salts; Caveolin 1; Cell Line, Tumor; Cholesterol; Cytokines; Deoxycholic Acid; Esophagus; Gastroesophageal Reflux; Gene Expression; Humans; Inflammation; Interleukin-6; Interleukin-8; Lipids; Membrane Microdomains; Neoplasms; NF-kappa B; Phosphorylation; Signal Transduction; src-Family Kinases

The frequency of esophageal adenocarcinoma is rising despite widespread use of proton pump inhibitors (PPIs), which heal reflux esophagitis but do not prevent reflux of weakly acidic gastric juice and bile in Barrett's esophagus patients. We aimed to determine if weakly acidic (pH 5.5) bile salt medium (WABM) causes DNA damage in Barrett's cells. Because p53 is inactivated frequently in Barrett's esophagus and p38 can assume p53 functions, we explored p38's role in DNA damage response and repair. We exposed Barrett's cells with or without p53 knockdown to WABM, and evaluated DNA damage, its response and repair, and whether these effects are p38 dependent. We also measured phospho-p38 in biopsies of Barrett's metaplasia exposed to deoxycholic acid (DCA). WABM caused phospho-H2AX increases that were blocked by a reactive oxygen species (ROS) scavenger. WABM increased phospho-p38 and reduced bromodeoxyuridine incorporation (an index of S phase entry). Repair of WABM-induced DNA damage proceeded through p38-mediated base excision repair (BER) associated with reduction-oxidation factor 1-apurinic/apyrimidinic endonuclease I (Ref-1/APE1). Cells treated with WABM supplemented with ursodeoxycholic acid (UDCA) exhibited enhanced p38-mediated responses to DNA damage. All of these effects were observed in p53-intact and p53-deficient Barrett's cells. In patients, esophageal DCA perfusion significantly increased phospho-p38 in Barrett's metaplasia. WABM exposure generates ROS, causing oxidative DNA damage in Barrett's cells, a mechanism possibly underlying the rising frequency of esophageal adenocarcinoma despite PPI usage. p38 plays a central role in oxidative DNA damage response and Ref-1/APE1-associated BER, suggesting potential chemopreventive roles for agents like UDCA that increase p38 activity in Barrett's esophagus.

Topics: Barrett Esophagus; Cell Line, Transformed; Cell Proliferation; Deoxycholic Acid; DNA Damage; DNA Repair; Epithelial Cells; Esophageal Mucosa; Female; Histones; Humans; Hydrogen-Ion Concentration; Male; Oxidative Stress; p38 Mitogen-Activated Protein Kinases; Phosphorylation; Primary Cell Culture; S Phase Cell Cycle Checkpoints; Signal Transduction; Tumor Suppressor Protein p53; Ursodeoxycholic Acid

Esophageal adenocarcinoma (EAC) incidence has been rapidly increasing, potentially associated with the prevalence of the risk factors gastroesophageal reflux disease (GERD), obesity, high-fat diet (HFD), and the precursor condition Barrett's esophagus (BE). EAC development occurs over several years, with stepwise changes of the squamous esophageal epithelium, through cardiac metaplasia, to BE, and then EAC. To establish the roles of GERD and HFD in initiating BE, we developed a dietary intervention model in C57/BL6 mice using experimental HFD and GERD (0.2% deoxycholic acid, DCA, in drinking water), and then analyzed the gastroesophageal junction tissue lipidome and microbiome to reveal potential mechanisms. Chronic (9 months) HFD alone induced esophageal inflammation and metaplasia, the first steps in BE/EAC pathogenesis. While 0.2% deoxycholic acid (DCA) alone had no effect on esophageal morphology, it synergized with HFD to increase inflammation severity and metaplasia length, potentially via increased microbiome diversity. Furthermore, we identify a tissue lipid signature for inflammation and metaplasia, which is characterized by elevated very-long-chain ceramides and reduced lysophospholipids. In summary, we report a non-transgenic mouse model, and a tissue lipid signature for early BE. Validation of the lipid signature in human patient cohorts could pave the way for specific dietary strategies to reduce the risk of BE in high-risk individuals.

Topics: Adenocarcinoma; Animals; Barrett Esophagus; Deoxycholic Acid; Diet, High-Fat; Disease Models, Animal; Esophageal Mucosa; Esophageal Neoplasms; Gastric Mucosa; Gastrointestinal Microbiome; Lipid Metabolism; Male; Mice; Mice, Inbred C57BL

The fundamental mechanisms underlying erosive oesophagitis and subsequent development of Barrett's oesophagus (BO) are poorly understood. Here, we investigated the contribution of specific components of the gastric refluxate on adhesion molecules involved in epithelial barrier maintenance. Cell line models of squamous epithelium (HET-1A) and BO (QH) were used to examine the effects of bile acids on cell adhesion to extracellular matrix proteins (Collagen, laminin, vitronectin, fibronectin) and expression of integrin ligands (α

Topics: Animals; Barrett Esophagus; Cell Adhesion; Cell Line; Collagen; Deoxycholic Acid; Disease Models, Animal; Epithelial Cells; Esophagitis; Fibronectins; Gastroesophageal Reflux; Gene Expression Profiling; Gene Expression Regulation; Humans; Integrin alphaV; Integrins; Laminin; Permeability; Protein Transport; Rats; Tissue Array Analysis; Vitronectin

Barrett's esophagus (BE) is essentially a metaplasia in which the normal stratified squamous epithelium is replaced by columnar epithelium. This study focuses on the involvement of OCT4 and SOX2, 2 key cell-reprogramming factors, in the deoxycholic acid (DCA)-induced expression of the intestinal hallmarks Cdx2 and MUC2 using both in vivo and in vitro models. Up-regulated expression of OCT4 and down-regulated expression of SOX2 were observed in BE compared with normal esophagus and esophagitis. Consistent with the data in vivo, DCA induced time-dependent expression of OCT4 at both the mRNA and protein levels and decreased nuclear expression of SOX2 in Het-1A cells. Down-regulation of OCT4 expression by siRNA abrogated DCA-induced expression of Cdx2 and MUC2, whereas siRNA against SOX2 significantly upregulated the expression of both Cdx2 and MUC2. Our data indicate that both OCT4 and SOX2 play important roles in the development of BE triggered by bile acid reflux.

Topics: Animals; Barrett Esophagus; CDX2 Transcription Factor; Cell Line; Cellular Reprogramming; Deoxycholic Acid; Disease Models, Animal; Epithelial Cells; Esophagitis; Esophagus; Gene Expression Regulation; Humans; Mucin-2; Octamer Transcription Factor-3; Phenotype; Rats; Rats, Sprague-Dawley; RNA, Small Interfering; Signal Transduction; SOXB1 Transcription Factors; Stem Cells

Barrett's esophagus is a metaplastic lesion. However, the cellular and molecular mechanisms involved are poorly understood. The aim of this study was to investigate the roles of KLF4 and BMP4 in the pathogenesis of Barrett's epithelium.. Immunohistochemistry was used to analyse the expression of KLF4, BMP4, CDX2, MUC2 and MUC5AC in human esophageal specimens. Human esophageal squamous epithelial cells were subjected to bile acid treatment and used in transfection experiments. Quantitative real-time PCR and Western blot analysis were used to detect the expression of KLF4, BMP4, CDX2, MUC2 and MUC5ac.. In human tissues, Barrett's epithelium strongly expressed BMP4, p-Smad1/5/8 and KLF4. Furthermore, bile acids increased the expression of BMP4, KLF4, p-Smad1/5/8, CDX2, MUC2 and MUC5ac in esophageal epithelial cells in a time-dependent manner. Moreover, we found that BMP4 up-regulated the expression of KLF4, CDX2, MUC2 and MUC5ac, but Noggin, a specific BMP4 antagonist, can block the expression of KLF4, CDX2, MUC2 and MUC5ac induced by BMP4. However, BMP4 cannot induce the expression of CDX2, MUC2 and MUC5ac in cells with KLF4 siRNA, and Noggin cannot block the expression of KLF4, CDX2, MUC2 and MUC5ac in cells transfected with the KLF4 expression vector.. Our results demonstrate that BMP4 promotes a phenotype change of an esophageal squamous epithelium via up-regulation of KLF4.

Topics: Adult; Aged; Barrett Esophagus; Biomarkers; Bone Morphogenetic Protein 4; Carrier Proteins; Cell Line; Deoxycholic Acid; Down-Regulation; Esophagus; Female; Humans; Immunohistochemistry; Kruppel-Like Factor 4; Kruppel-Like Transcription Factors; Male; Middle Aged; Mucins; Phenotype; Phosphorylation; RNA, Messenger; RNA, Small Interfering; Signal Transduction; Smad Proteins; Up-Regulation

Induction by bile acid of caudal type homeobox 2 (CDX2) and cyclooxygenase-2 (COX-2) expression via nuclear factor-κB (NF-κB) activation is a critical event in the development of Barrett's esophagus (BE) and esophageal adenocarcinoma (EAC). Guggulsterone (GS) is a plant sterol that inhibits NF-κB activity. Here, we evaluated whether GS has either or both chemopreventive or therapeutic effects against EAC.. Two EAC cells lines were treated with deoxycholic acid (DCA) in the presence of GS or vehicle. The levels of transcription and translation of IκBα, CDX2, and COX-2 were determined. Prostaglandin E2 (PGE2) levels, cell viability, and cell cycle distribution were assessed as well.. GS inhibited DCA-induced IκBα phosphorylation. GS and the NF-κB inhibitor BAY11-7085 suppressed DCA-induced CDX2 and COX-2 expression in EAC cells. GS also suppressed basal transcription levels of CDX2 and COX-2 and reduced constitutive synthesis of COX-2 and PGE2. Further, GS reduced the viability of EAC cells, increased their numbers in the apoptotic sub-G1 fraction.. GS suppressed DCA-induced and NF-κB-dependent activation of CDX2 and COX-2 expression. Further, GS also reduced the viability of EAC cells. GS may serve as candidate for preventing and treating EAC and BE.

Topics: Adenocarcinoma; Anticarcinogenic Agents; Apoptosis; Barrett Esophagus; CDX2 Transcription Factor; Cell Line; Cell Line, Tumor; Cell Proliferation; Cell Survival; Cholagogues and Choleretics; Cyclooxygenase 2; Deoxycholic Acid; Dinoprostone; Drug Screening Assays, Antitumor; Esophageal Neoplasms; Homeodomain Proteins; Humans; I-kappa B Proteins; Neoplasm Proteins; NF-kappa B; Phosphorylation; Pregnenediones

It is generally accepted that esophageal adenocarcinoma arises from a Barrett's metaplastic lesion. Altered glycoprotein expression has been demonstrated in tissue from patients with Barrett's esophagus and esophageal cancer but the mechanisms regarding such changes are unknown. The bile acid deoxycholic acid (DCA) alters many cell signaling pathways and is implicated in esophageal cancer progression. We have demonstrated that DCA disrupts Golgi structure and affects protein secretion and glycosylation processes in cell lines derived from normal squamous epithelium (HET-1A) and Barrett's metaplastic epithelium (QH). Cell surface expression of glycans was identified using carbohydrate-specific probes (wheat germ agglutinate, conconavalin A, peanut agglutinin, lithocholic acid and Ulex europaeus agglutinin) that monitored N-glycosylation, O-glycosylation and core fucosylation in resting and DCA-treated cells. DCA altered intracellular localization and reduced cell surface expression of N-acetyl-D-glucosamine, α-methyl-mannopyranoside (Man/Glc) and fucose in both cell lines. Furthermore, DCA reduced the expression of epithelial growth factor receptor and E-cadherin in a manner analogous to treatment of cells with the N-glycan biosynthesis inhibitor tunicamycin. This is the first study to identify an altered Golgi structure and glycomic profile in response to DCA in esophageal epithelial cells, a process which could potentially contribute to metaplasia, dysplasia and cancer of the esophagus.

Topics: Barrett Esophagus; Cadherins; Deoxycholic Acid; Epithelial Cells; ErbB Receptors; Esophagus; Fucose; Glycosylation; Golgi Apparatus; Humans

Beclin-1 has a central role in the regulation of autophagy. Barrett's esophagus (BE) is associated with a significantly increased risk for the development of esophageal adenocarcinoma (EAC). In the current study, we evaluated the role of Beclin-1 and autophagy in the EAC. Biopsies obtained from patients with BE and EAC, tissues from a rat model of BE and EAC, and esophageal cell lines were evaluated for the expression of Beclin-1 by immunohistochemistry, immunoblotting, or RT-PCR. Since reflux of bile acids is important in EAC, we also evaluated the effect of exposure to deoxycholic acid (DCA) on autophagy and Beclin-1 expression. Beclin-1 expression was high in squamous epithelium and nondysplastic BE, whereas its expression was low in dysplastic BE and EAC. The same pattern of expression was observed in rat tissues and in esophageal cell lines. Normal esophageal epithelium and HET-1A cells (derived from normal squamous epithelium) show high levels of Beclin-1, but lower levels of Beclin-1 were found in BE and EAC cell lines (CP-A, CP-C, and OE33). Acute exposure to DCA led to increased Beclin-1 expression and increased autophagy as evaluated by electron microscopy and counting percentage of GFP-LC3-positive BE cells with punctate pattern. In contrast, chronic exposure to DCA did not result in the alteration of Beclin-1 levels or autophagy. In summary, these data suggest that autophagy is initially activated in response to bile acids, but chronic exposure to bile acids leads to decreased Beclin-1 expression and autophagy resistance.

Topics: Adenocarcinoma; Amino Acids; Animals; Apoptosis Regulatory Proteins; Autophagy; Barrett Esophagus; Beclin-1; Bile Acids and Salts; Blotting, Western; Cell Line, Tumor; Cell Proliferation; Deoxycholic Acid; Disease Progression; Esophageal Neoplasms; Humans; Immunohistochemistry; Membrane Proteins; Microarray Analysis; Microscopy, Confocal; Microscopy, Electron, Transmission; Rats; Real-Time Polymerase Chain Reaction; RNA; RNA, Small Interfering

Cdx2 expression in esophageal stem cells induced by reflux bile acids may be an important factor for development of Barrett's esophagus, whereas Notch signaling is a molecular signaling pathway that plays an important role in the determination of cell differentiation. ATOH1 (a factor associated with Notch signaling) plays an important role in differentiation of stem cells into goblet cells. However, the relationship between the Notch signaling pathway and Cdx2 expression in the development of Barrett's esophagus has not been explored. The aim of this study was to investigate the interrelationship between Notch signaling and Cdx2 in esophageal epithelial cells. The expressions of Cdx2, MUC2, and intracellular signaling molecules related to Notch signaling (Notch1, Hes1, and ATOH1) were examined using real-time polymerase chain reaction (PCR) and immunohistochemical staining with biopsy specimens obtained from esophageal intestinal metaplasia (IM) with goblet cells (IM⁺) and columnar epithelium not accompanied by goblet cells (IM⁻). For in vitro experiments, we employed human esophageal epithelial cell lines (OE33, OE19, and Het-1A). After forced Cdx2 expression by applying a Cdx2 expression vector to the cells, changes in the expressions of Notch1, Hes1, ATOH1, Cdx2, and MUC2 were analyzed by real-time PCR and western blot analysis. Changes in expressions of Notch1, Hes1, ATOH1, Cdx2, and MUC2 in cells were analyzed following stimulation with bile acids in the presence or absence of Cdx2 blocking with Cdx2-siRNA. Suppressed Hes1 and enhanced ATOH1 and MUC2 expressions were identified in IM⁺ specimens. Forced expression of Cdx2 in cells suppressed Hes1, and enhanced ATOH1 and MUC2 expressions, whereas bile acids suppressed Hes1, and enhanced ATOH1, Cdx2, and MUC2 expressions. On the other hand, these effects were blocked by siRNA-based Cdx2 downregulation. Enhanced expression of Cdx2 by stimulation with bile acids may induce intestinal differentiation of esophageal columnar cells by interaction with the Notch signaling pathway.

Topics: Adenocarcinoma; Aged; Barrett Esophagus; Basic Helix-Loop-Helix Transcription Factors; CDX2 Transcription Factor; Cell Line, Tumor; Cholic Acid; Deoxycholic Acid; Epithelial Cells; Esophageal Neoplasms; Esophagus; Female; Gene Expression; Gene Silencing; Goblet Cells; Homeodomain Proteins; Humans; Male; Metaplasia; Mucin-2; Real-Time Polymerase Chain Reaction; Receptor, Notch1; RNA, Small Interfering; Signal Transduction; Transcription Factor HES-1; Transfection

Decreases in Sonic hedgehog (SHH) and CDX2 expression are associated with atrophy and intestinal metaplasia in the gastric mucosa. The pathogenesis of development of Barrett's oesophagus is still unclear.. To examine the gene expression of CDX2 and SHH and their signalling pathways in the columnar epithelium and the association with endoscopic appearance, gastric pH or bile acids.. Sixty-three patients with metaplastic columnar epithelium of the lower oesophagus were studied. Whole biopsy specimens and microdissected tissues were examined for messenger RNA.. BMP4 expression was significantly higher in patients with tubular mucosal patterns of columnar epithelium visualised by Narrow Band Imaging with magnification. The expression of SHH was significantly lower and that of CDX2 was higher in the goblet columnar epithelium than in non-goblet columnar epithelium. CDX2 expression was significantly higher in the patients with hypoacidity than in the others. BMP4 and PTCH1 expression was significantly higher in the group with higher concentrations of deoxycholic acid than in the group with lower concentrations.. SHH might be the initial factor inducing columnar metaplasia, and subsequent or simultaneous BMP4 stimuli might induce the CDX2 expression that causes goblet-cell metaplasia.

Topics: Aged; Barrett Esophagus; Biomarkers; Bone Morphogenetic Protein 4; CDX2 Transcription Factor; Deoxycholic Acid; Epithelial Cells; Esophagus; Female; Gastric Juice; Gene Expression; Hedgehog Proteins; Homeodomain Proteins; Humans; Hydrogen-Ion Concentration; Male; Middle Aged; Mucin 5AC; Mucin-6; Patched Receptors; Patched-1 Receptor; Receptors, Cell Surface; Signal Transduction

The development of Barrett's esophagus and its progression to adenocarcinoma are clearly linked to reflux of acid and bile. Our objective in this study was to develop an optimized ex vivo biopsy culture technique to study the molecular signaling events induced after insult with individual refluxate constituents. We illustrate the utility of this method by showing results for NF-kB centered cell signaling, and compare the results with those obtained from esophageal cell lines. We show that upregulation of the two NF-kB target genes show differences in pH preference, with IL-8 being preferentially upregulated by DCA at neutral pH, and IkB being upregulated by neutral DCA, acidic DCA, and acid alone. This was found to be true in both cell lines and biopsy cultures. The maximum responses were noted in both models when mixed reflux (DCA at pH 6) was utilized, perhaps reflecting the pH preference of DCA (pKa 6.2). Both the optimized ex vivo models, and the in vitro cell lines show that bile and acid are capable of inducing NF-kB dependent gene expression, with some interesting differences in preferred transcriptional target. In conclusion, in both cells and cultured biopsies, similar reflux driven gene expression changes were noted, with maximum effects noted with DCA exposures at pH 6.

Topics: Adenocarcinoma; Barrett Esophagus; Cell Line, Tumor; Cholagogues and Choleretics; Deoxycholic Acid; Esophageal Neoplasms; Gene Expression; Humans; Hydrogen-Ion Concentration; I-kappa B Proteins; In Vitro Techniques; Interleukin-8; NF-kappa B p50 Subunit; Signal Transduction; Up-Regulation

Cancer-related inflammation recently has been proposed as a major physiological hallmark of malignancy. Some genetic alterations known to promote cellular proliferation and induce malignant transformation also may participate in an intrinsic inflammatory pathway that produces a cancer-promoting inflammatory microenvironment. Little is known about this intrinsic inflammatory pathway in Barrett's esophagus. We have used a series of nontransformed and transformed human Barrett's epithelial cell lines developed in our laboratory to explore the potential contribution of interleukin (IL)-6 and signal transducer and activator of transcription (STAT3) (key molecules in the intrinsic inflammatory pathway) to Barrett's carcinogenesis. We determined IL-6 mRNA expression and protein secretion and protein expression of activated phospho-STAT3 and its downstream target myeloid cell leukemia (mcl)-1 (Mcl-1). We used an IL-6 blocking antibody and two JAK kinase inhibitors (AG490 and JAK inhibitor I) to assess whether STAT3 activation is IL-6 dependent. We also used small interfering RNAs (siRNAs) to STAT3 and Mcl-1 to assess effects of STAT3 pathway inhibition on apoptosis. Phospho-STAT3 was expressed only by transformed Barrett's cells, which also exhibited higher levels of IL-6 mRNA and of IL-6 and Mcl-1 proteins than nontransformed Barrett's cells. STAT3 phosphorylation could be blocked by IL-6 blocking antibody and by AG490 and JAK inhibitor I. In transformed Barrett's cells, rates of apoptosis following exposure to deoxycholic acid were significantly increased by transfection with siRNAs for STAT3 and Mcl-1. We conclude that activation of the IL-6/STAT3 pathway in transformed Barrett's epithelial cells enables them to resist apoptosis. These findings demonstrate a possible contribution of the intrinsic inflammatory pathway to carcinogenesis in Barrett's esophagus.

Topics: Apoptosis; Barrett Esophagus; Cell Line, Transformed; Cell Transformation, Neoplastic; Cyclin-Dependent Kinase Inhibitor p16; Deoxycholic Acid; Epithelial Cells; Esophageal Neoplasms; Esophagitis; Esophagus; Genes, ras; Humans; Interleukin-6; Janus Kinases; Myeloid Cell Leukemia Sequence 1 Protein; Phosphorylation; Protein Kinase Inhibitors; Proto-Oncogene Proteins c-bcl-2; RNA Interference; RNA, Messenger; Signal Transduction; STAT3 Transcription Factor; Telomerase; Time Factors; Transfection; Tumor Microenvironment; Tumor Suppressor Protein p53; Tyrosine

Recently, a mouse model for Barrett's esophagus based on a zinc-deficient diet supplemented with deoxycholic bile acids has been published. The aim of this study was to attempt to reproduce these data and extend them by employing genetically modified mice and intraperitoneal iron supplementation. The study design encompassed six experimental groups (wild type, Apc-mutant and Smad4-mutant mice, with or without iron injections), with all animals fed with the zinc-deficient diet supplemented with deoxycholic bile acids. All treatments were started at 3-5 weeks of age (the majority [78%] at 5 weeks). Animals were scheduled for euthanasia at two distinct time points, namely at 3 and 6 months of age. All mice showed signs of considerable distress already 4 weeks after the start of the modified diets, and had to be euthanized before the first evaluation time point (mean age 9.3 weeks, range 5-15 weeks). No differences were observed between wild type and genetically modified mice, or between animals with or without iron supplementation. On histological examination, we could not detect any lesions (Barrett's esophagus-like or tumors) other than esophagitis. In the currently presented experimental settings, we were not able to reproduce the mouse model according to which Barrett's-like lesions could be detected in animals fed with the zinc-deficient diet supplemented with deoxycholic bile acids.

Topics: Animals; Barrett Esophagus; Cholagogues and Choleretics; Deoxycholic Acid; Diet; Dietary Supplements; Disease Models, Animal; Esophagitis; Iron; Mice; Mice, Mutant Strains; Reproducibility of Results; Smad4 Protein; Trace Elements; Zinc

Gastroesophageal reflux is associated with adenocarcinoma in Barrett's esophagus, but the incidence of this tumor is rising, despite widespread use of acid-suppressing medications. This suggests that refluxed material other than acid might contribute to carcinogenesis. We looked for potentially carcinogenetic effects of two bile acids, deoxycholic acid (DCA) and ursodeoxycholic acid (UDCA), on Barrett's epithelial cells in vitro and in vivo. We exposed Barrett's (BAR-T) cells to DCA or UDCA and studied the generation of reactive oxygen/nitrogen species (ROS/RNS); expression of phosphorylated H2AX (a marker of DNA damage), phosphorylated IkBα, and phosphorylated p65 (activated NF-κB pathway proteins); and apoptosis. During endoscopy in patients, we took biopsy specimens of Barrett's mucosa before and after esophageal perfusion with DCA or UDCA and assessed DNA damage and NF-κB activation. Exposure to DCA, but not UDCA, resulted in ROS/RNS production, DNA damage, and NF-κB activation but did not increase the rate of apoptosis in BAR-T cells. Pretreatment with N-acetyl-l-cysteine (a ROS scavenger) prevented DNA damage after DCA exposure, and DCA did induce apoptosis in cells treated with NF-κB inhibitors (BAY 11-7085 or AdIκB superrepressor). DNA damage and NF-κB activation were detected in biopsy specimens of Barrett's mucosa taken after esophageal perfusion with DCA, but not UDCA. These data show that, in Barrett's epithelial cells, DCA induces ROS/RNS production, which causes genotoxic injury, and simultaneously induces activation of the NF-κB pathway, which enables cells with DNA damage to resist apoptosis. We have demonstrated molecular mechanisms whereby bile reflux might contribute to carcinogenesis in Barrett's esophagus.

Topics: Aged; Analysis of Variance; Animals; Apoptosis; Barrett Esophagus; Cell Line; Cell Transformation, Neoplastic; Deoxycholic Acid; DNA Damage; Epithelial Cells; Histones; Humans; I-kappa B Proteins; Male; Middle Aged; NF-kappa B; NF-KappaB Inhibitor alpha; Rats; Reactive Nitrogen Species; Reactive Oxygen Species; Signal Transduction; Ursodeoxycholic Acid

Activation-induced cytidine deaminase (AID) induces somatic mutations in various host genes of non-lymphoid tissues, thereby contributing to carcinogenesis. We recently demonstrated that Helicobacter pylori infection and/or proinflammatory cytokine stimulation triggers aberrant AID expression in gastric epithelial cells, causing mutations in the tumour-suppressor TP53 gene. The findings of the present study provide evidence of ectopic AID expression in Barrett's oesophagus and Barrett's oesophageal adenocarcinoma, a cancer that develops under chronic inflammatory conditions. Immunoreactivity for endogenous AID was observed in 24 of 28 (85.7%) specimens of the columnar cell-lined Barrett's oesophagus and in 20 of 22 (90.9%) of Barrett's adenocarcinoma, whereas weak or no AID protein expression was detectable in normal squamous epithelial cells of the oesophagus. We validated these results by analysing tissue specimens from another cohort comprising 16 cases with Barrett's oesophagus and four cases with Barrett's adenocarcinoma. In vitro treatment of human non-neoplastic oesophageal squamous-derived cells with sodium salt deoxycholic acid induced ectopic AID expression via the nuclear factor-kappaB activation pathway. These findings suggest that aberrant AID expression occurs in a substantial proportion of Barrett's epithelium, at least in part due to bile acid stimulation. Considering the genotoxic activity of AID, our current findings suggest that aberrant AID expression might enhance the susceptibility to genetic alterations in Barrett's columnar-lined epithelial cells, leading to cancer development.

Topics: Adenocarcinoma; Adult; Aged; Aged, 80 and over; Barrett Esophagus; Bile Acids and Salts; Blotting, Western; Cells, Cultured; Cytidine Deaminase; Deoxycholic Acid; Esophageal Neoplasms; Esophagus; Female; Humans; Immunoenzyme Techniques; Male; Middle Aged; NF-kappa B; Real-Time Polymerase Chain Reaction; RNA, Messenger

Barrett's esophagus (BE) is a premalignant condition associated with the development of esophageal adenocarcinoma (EAC). Previous studies have implicated hydrophobic bile acids and gastric acid in BE and EAC pathogenesis. In this study, we tested the hypothesis that DNA damage, cytotoxicity and oxidative stress induced by bile acids and gastric acid can be attenuated by the cytoprotective, hydrophilic bile acid glycoursodeoxycholic acid (GUDCA). Non-dysplastic BE cells were exposed for 10 min to pH 4 and/or bile acid cocktail or to pH 4 and a modified cocktail consisting of a mixture of bile acids and GUDCA. DNA damage was evaluated by the comet assay; cell viability and proliferation were measured by trypan blue staining and the MTS assay; reactive oxygen species (ROS) were measured using hydroethidium staining; oxidative DNA/RNA damage was detected by immunostaining with antibody against 8-OH-dG; thiol levels were measured by 5-chloromethylfluorescein diacetate (CMFDA) staining; and the expression of antioxidant proteins was evaluated by western blotting. DNA damage and oxidative stress were significantly increased, while thiol levels were decreased in BE cells treated with pH 4 and bile acid cocktail compared with cells treated with pH 4 alone or untreated cells. Bile acids and low pH also significantly decreased cell proliferation. Expression of the antioxidant enzymes, MnSOD and CuZnSOD, was elevated in the cells treated with bile acids and low pH. When GUDCA was included in the medium, all these effects of pH 4 and bile acids were markedly reduced. In conclusion, treatment of BE cells with acidified medium and a bile acid cocktail at physiologically relevant concentrations induces DNA damage, cytotoxicity, and ROS. The cytoprotective bile acid, GUDCA, inhibits these deleterious effects by inhibiting oxidative stress.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Antioxidants; Barrett Esophagus; Bile Acids and Salts; Cell Line; Cell Proliferation; Cell Survival; Cytoprotection; Deoxycholic Acid; Deoxyguanosine; DNA Damage; Esophagus; Free Radical Scavengers; Glycochenodeoxycholic Acid; Glycocholic Acid; Glycodeoxycholic Acid; Humans; Hydrogen-Ion Concentration; Oxidative Stress; Protective Agents; Reactive Oxygen Species; RNA; Sulfhydryl Compounds; Superoxide Dismutase; Taurocholic Acid; Time Factors; Ursodeoxycholic Acid

Reflux of gastroduodenal contents and consequent inflammatory responses are associated with the development of Barrett's oesophagus (BO) and the promotion of oesophageal adenocarcinoma (OAC). Deregulation of inflammatory processes is a hallmark of oesophageal cancer. In this study, we aimed to investigate (i) the transcriptional responses to deoxycholic acid (DCA) in cell lines representative of either end of the oesophageal cancer sequence, (ii) the expression of DCA-regulated genes in data charting oesophageal carcinogenesis and (iii) the impact of these genes on oesophageal inflammatory signalling. Gene expression microarrays were utilized to demonstrate differential transcriptional responses between squamous (HET-1A) and adenomatous (SKGT4) cell lines exposed to DCA. Differential basal and DCA-inducible expression of cytokines such as interleukin (IL) 8 was observed between both cell types. A cohort of DCA-regulated genes specific to each cell type was identified in microarray experimentation and subsequently validated. Cell type-specific genes included TRB3, CXCL14, GDF15 and LIF in HET-1A cells, with COX2-, ESM1-, URHF1- and IL1alpha-and IL1beta-specific expression in SKGT4 cells. Over 30% of the genes altered in BO and OAC were shown to be regulated by DCA utilizing an integrative genomic approach. One such gene, tribbles-homology-3 (TRB3) was induced specifically in HET-1A cells, absent in SKGT4 cells and decreased in BO samples in silico and in vivo. Inhibition and re-introduction of TRB3 in HET-1A and SKGT4 cells, respectively, demonstrated the ability of TRB3 to regulate inflammatory signalling through nuclear factor-kappaB. This study identifies mechanisms through which bile acids such as DCA, in conjunction with the loss of key signalling molecules, could regulate oesophageal metaplasticity.

Topics: Barrett Esophagus; Cell Cycle Proteins; Cell Line, Tumor; Deoxycholic Acid; Down-Regulation; Esophagus; Gene Expression Profiling; Gene Expression Regulation; Genomics; Humans; Interleukin-8; NF-kappa B; Protein Serine-Threonine Kinases; Repressor Proteins; Response Elements; Signal Transduction

Bile salts play an important pathogenic role in the development of Barrett adenocarcinoma (BA). However, the precise role of different bile salts in this process is still unknown. The aim of the present study was to compare the effects of two different bile salts, deoxycholic acid (DCA) and ursodeoxycholic acid (UDCA) on the expression of COX-2, CDX-2 and DNA repair enzymes (MUTYH, OGG-1) in the Barrett epithelial cancer cells (OE-19). OE-19 cells were incubated with DCAor UDCA(100 microM or 300 microM at pH=7.0) over 24 h. To investigate the involvement of NF kappaB, in separate experiments the cells were incubated with DCA in the presence of proteosome inhibitor (MG-132). Cells cycle and apoptosis were analyzed by FACS analysis. After incubation of OE-19 cells with bile salts, the expression of mRNA of COX-2, DNA repair enzymes (MUTYH, OGG-1) and caudal-related homebox transcription factor CDX-2 were measured by quantitative RT-PCR. OE-19 cell were also transfected with siRNA-RelA (p65) to asses effect of NF kappaB inactivation on COX-2 and CDX2 expression. DCA caused a stronger reduction in cell survival of OE-19 cells than UDCA. In addition, DCA stimulated directly the translocation of NF kappaB p65 (active form) in the nuclei of OE-19 cells. DCA caused stronger than UDCA stimulation of the COX-2 mRNA expression in these cells and this effect was significantly attenuated by the addition of inhibitor of NF kappaB activity (proteosome inhibitor MG-132). siRNA-RelA reduced expression not only of NF kappaB but also expression of COX-2 as well as CDX-2 mRNA. DCA caused stronger downregulation of mRNA for DNA repair enzymes MUTYH and OGG-1 than UDCA. In contrast, UDCA induced stronger CDX-2 mRNA expression than DCA in OE-19 cells. We conclude that bile salts are involved in the carcinogenesis of Barrett adenocarcinoma via inhibition of DNA repair enzymes and induction of COX-2 and this last effect is, at least partly, mediated by NF kappaB. DCA shows carcinogenic potential due to high upregulation of COX-2, CDX-2 and downregulation of DNA repair enzymes.

Topics: Adenocarcinoma; Barrett Esophagus; CDX2 Transcription Factor; Cell Line, Tumor; Cyclooxygenase 2; Deoxycholic Acid; DNA Glycosylases; Down-Regulation; Esophageal Neoplasms; Gene Expression Regulation, Neoplastic; Homeodomain Proteins; Humans; NF-kappa B; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Up-Regulation; Ursodeoxycholic Acid

The progression from Barrett's metaplasia to adenocarcinoma is associated with the acquirement of an apoptosis-resistant phenotype. The bile acid deoxycholate (DCA) has been proposed to play an important role in the development of esophageal adenocarcinoma, but the precise molecular mechanisms remain undefined. The aim of this study was to investigate DCA-stimulated COX-2 signaling pathways and their possible contribution to deregulated cell survival and apoptosis in esophageal adenocarcinoma cells.. Following exposure of SKGT-4 cells to DCA, protein levels of COX-2, MAPK and PARP were examined by immunoblotting. AP-1 activity was assessed by mobility shift assay. DCA-induced toxicity was assessed by DNA fragmentation and MTT assay.. DCA induced persistent activation of the AP-1 transcription factor with Fra-1 and JunB identified as the predominant components of the DCA-induced AP-1 complex. DCA activated Fra-1 via the Erk1/2- and p38 MAPK while Erk1/2 is upstream of JunB. Moreover, DCA stimulation mediated inhibition of proliferation with concomitant low levels of caspase-3-dependent PARP cleavage and DNA fragmentation. Induction of the anti-apoptotic protein COX-2 by DCA, via MAPK/AP-1 pathway appeared to balance the DCA mediated activation of pro-apoptotic markers such as PARP cleavage and DNA fragmentation. Both of these markers were increased upon COX-2 suppression by aspirin pretreatment prior to DCA exposure.. DCA regulates both apoptosis and COX-2-regulated cell survival in esophageal cells suggesting that the balance between these two opposing signals may determine the transformation potential of DCA as a component of the refluxate.

Topics: Adenocarcinoma; Apoptosis; Barrett Esophagus; Cell Growth Processes; Cell Line, Tumor; Collagen Type XI; Cyclooxygenase 2; Deoxycholic Acid; DNA, Neoplasm; Enzyme Induction; Esophageal Neoplasms; Humans; Mitogen-Activated Protein Kinase 1; Mitogen-Activated Protein Kinase 3; Mitogen-Activated Protein Kinases; p38 Mitogen-Activated Protein Kinases; Proto-Oncogene Proteins c-fos; Proto-Oncogene Proteins c-jun; Signal Transduction; Transcription Factor AP-1

Barrett's esophagus (BE) is the predominant risk factor for the development of esophageal adenocarcinoma. BE is characterized by intestinal metaplasia with goblet cells. Reflux of bile acids is known to induce intestinal metaplasia, but the mechanisms are unclear. Inhibition of Notch signaling accompanied by increased Hath1 and induction of caudal homeobox 2 (CDX2) may be involved in development of intestinal goblet cells.. Esophageal adenocarcinoma cell lines OE19 and OE33 were exposed for up to 8 hours to DCA (100-300 microM), and for up to 24 hours with and without the gamma-secretase inhibitor, DAPT (20 microM). Notch signaling components and CDX2 levels were measured by real-time PCR (for mRNA) and by Western blot analysis (for proteins).. DCA induced a time and concentration dependent decrease in Notch pathway components mRNAs in OE33 and in the proteins in both cell lines. CDX2 mRNA and Hath1 protein were increased in OE19 by 3-fold. Inhibition of Notch pathway by DAPT decreased downstream Notch signaling mRNAs and proteins in both cell lines and increased Hath1 and CDX2 proteins only in OE19.. Bile acid inhibition of Notch signaling in esophageal cells is correlated with an increase in Hath1 and CDX2 and may be one of the key processes contributing to the formation of BE.

Topics: Barrett Esophagus; Basic Helix-Loop-Helix Transcription Factors; Bile Acids and Salts; CDX2 Transcription Factor; Cell Line, Tumor; Deoxycholic Acid; Dipeptides; Esophagus; Gene Expression Regulation; Homeodomain Proteins; Humans; Receptors, Notch; RNA, Messenger; Signal Transduction; Transcription Factor HES-1

Deoxycholic acid (DCA) is a secondary bile acid implicated in various cancers of the gastrointestinal (GI) tract. In oesophageal adenocarcinoma, DCA is believed to contribute to carcinogenesis during reflux where stomach contents enter the lower oesophagus. It is imperative that we understand the mechanisms whereby oesophageal carcinogens function in order that therapeutic options may be developed. We have previously shown that DCA can damage chromosomes and does so through its generation of reactive oxygen species (ROS). We show here, after detailed experiments, that DCA appears to have a non-linear dose response for DNA damage. DCA induces DNA damage (as measured by the micronucleus assay) at doses of 100 microM and higher in oesophageal OE33 cells, but fails to induce such DNA damage below this cut-off dose. We also show that in terms of NF-kappaB activation (as measured by up-regulation of two NF-kappaB target genes) by DCA, a similar dose response is observed. This dose-response data may be important clinically as DCA exposure to the oesophagus may be used as a way to identify the 10% of Barrett's oesophagus patients currently progressing to cancer from the 90% of patients who do not progress. Only quantitative studies measuring DCA concentrations in refluxates correlated with histological progression will answer this question. We further show here that ROS are behind DCAs ability to activate NF-kappaB as antioxidants (epigallocatechin gallate, resveratrol and vitamin C) abrogate DCAs ability to up-regulate NF-kappaB-controlled genes. In conclusion, low doses of DCA appear to be less biologically significant in vitro. If this were to be confirmed in vivo, it might suggest that reflux patients with low DCA concentrations may be at a lower risk of cancer progression compared to patients with high levels of DCA in their refluxate. Either way, antioxidant supplementation may possibly help prevent the deleterious effects of DCA in the whole GI tract.

Topics: Adenocarcinoma; Barrett Esophagus; Cell Line, Tumor; Cell Transformation, Neoplastic; Deoxycholic Acid; DNA; DNA Damage; Esophageal Neoplasms; Esophagus; Gene Expression; Gene Expression Regulation; Humans; Micronucleus Tests; Mutagens; NF-kappa B; Reactive Oxygen Species

Obesity is an important risk factor for Barrett adenocarcinoma. However, the role of adiponectin (anti-inflammatory adipokine from adipose tissue) and ghrelin (orexigenic peptide gastric origin) on the progression of Barrett's carcinogenesis has not been investigated so far. The aim of the present study was: (1) to compare the expression of adiponectin and ghrelin receptors in Barrett's esophagus and in normal squamous epithelium; (2) to assess the effect of adiponectin and ghrelin on apoptosis in Barrett's adenocarcinoma cells in vitro; and (3) to investigate the effect of ghrelin on IL-1beta and COX-2 expression in OE-19 cells incubated with TNFalpha.. The expression of ghrelin and adiponectin receptors (GHS-R1a, Adipo-R1, Adipo R-2) in biopsies from Barrett's esophagus and in Barrett's adenocarcinoma cell line OE-19 was assessed by quantitative RT-PCR (qRT-PCR). The OE-19 cells were also incubated with adiponectin (5-10 microg/ml), and the apoptosis and proliferation were assessed by FACS and MTT assays. Additionally, effects of adiponectin on the mRNA and protein expression of proapoptotic Bax and antiapoptotic Bcl-2 were assessed by RT-PCR and Western blot, respectively. In two different in vitro models of esophagitis the OE-19 cells were incubated with ghrelin alone or in the presence of TNFalpha or bile acids in the normal or pulse acidified medium, and the expression of IL-1beta and COX-2 as markers for inflammation were assessed by FACS and qRT-PCR, respectively.. Adiponectin caused a significant increase in apoptosis, and this affect was accompanied by increased Bax and decreased Bcl-2 expression. In contrast, ghrelin had no effect on apoptosis of OE-19 cells incubated in neutral or acidified medium with or without addition of deoxycholic acid. At the mRNA level, the expression of adiponectin receptors (Adipo-R1, Adipo-R2) was decreased, and the expression of ghrelin receptor (GHS-R1a) was increased in Barrett's mucosa. Ghrelin caused a decrease in TNFalpha-induced COX-2 and IL-1beta expression in OE-19 cells.. Adiponectin and ghrelin have an inhibitory effect on Barrett's carcinogenesis by two different mechanisms: (1) by an increase in apoptosis by adiponectin, and (2) by anti-inflammatory actions of ghrelin. The decrease in levels of these two peptides in obesity may explain the progression of Barrett's carcinoma in obese individuals.

Topics: Adenocarcinoma; Adiponectin; Apoptosis; Barrett Esophagus; Cell Line, Tumor; Culture Media; Cyclooxygenase 2; Deoxycholic Acid; Epithelium; Esophageal Neoplasms; Ghrelin; Humans; Hydrogen-Ion Concentration; Interleukin-1beta; Receptors, Adiponectin; Receptors, Ghrelin; Tumor Necrosis Factor-alpha

Bile acids are often refluxed into the lower oesophagus and are candidate carcinogens in the development of oesophageal adenocarcinoma. We show here that the secondary bile acid, deoxycholic acid (DCA), is the only one of the commonly refluxed bile acids tested here, to show genotoxicity, in terms of chromosome damage and mutation induction in the human p53 gene. This genotoxicity was apparent at both neutral and acidic pH, whilst there was a considerable increase in bile-induced toxicity at acidic pH. The higher levels of cell death and low cell survival rates at acidic pH may imply that acid bile exposure is toxic rather than carcinogenic, as dead cells do not seed cancer development. We also show that DCA (at neutral and acid pH) induced the release of reactive oxygen species (ROS) within the cytoplasm of exposed cells. We further demonstrate that the genotoxicity of DCA is ROS mediated, as micronucleus induction was significantly reduced when cells were treated with DCA + the anti-oxidant vitamin C. In conclusion, we show that DCA, is an effective genotoxin at both neutral and acidic pH. As bile acids like DCA can induce DNA damage at neutral pH, suppressing the acidity of the refluxate will not completely remove its carcinogenic potential. The genotoxicity of DCA is however, ROS dependent, hence anti-oxidant supplementation, in addition to acid suppression may block DCA driven carcinogenesis in Barrett's patients.

Topics: Adenocarcinoma; Antioxidants; Ascorbic Acid; Barrett Esophagus; Carcinoma, Squamous Cell; Cell Survival; Deoxycholic Acid; Detergents; DNA Damage; Esophageal Neoplasms; Humans; Hydrogen-Ion Concentration; Micronucleus Tests; Reactive Oxygen Species; Tumor Cells, Cultured; Tumor Suppressor Protein p53

p63 is a member of the p53 protein family that regulates differentiation and morphogenesis in epithelial tissues and is required for the formation of squamous epithelia. Barrett's mucosa is a glandular metaplasia of the squamous epithelium that develops in the lower esophagus in the context of chronic, gastroesophageal reflux and is considered as a precursor for adenocarcinoma. Normal or squamous cancer esophageal cells were exposed to deoxycholic acid (DCA, 50, 100, or 200 microM) and chenodeoxycholic and taurochenodeoxycholic acid at pH 5. p63 and cyclooxygenase-2 (COX-2) expressions were studied by Western blot and RT-PCR. DCA exposure at pH 5 led to a spectacular decrease in the levels of all isoforms of the p63 proteins. This decrease was observed within minutes of exposure, with a synergistic effect between DCA and acid. Within the same time frame, levels of p63 mRNA were relatively unaffected, whereas levels of COX-2, a marker of stress responses often induced in Barrett's mucosa, were increased. Similar results were obtained with chenodeoxycholic acid but not its taurine conjugate at pH 5. Proteasome inhibition by lactacystin or MG-132 partially blocked the decrease in p63, suggesting a posttranslational degradation mechanism. These results show that combined exposure to bile salt and acid downregulates a critical regulator of squamous differentiation, providing a mechanism to explain the replacement of squamous epithelium by a glandular metaplasia upon exposure of the lower esophagus to gastric reflux.

Topics: Acetylcysteine; Apoptosis; Barrett Esophagus; Carcinoma, Squamous Cell; Cell Line, Tumor; Cells, Cultured; Chenodeoxycholic Acid; Cyclooxygenase 2; Deoxycholic Acid; DNA-Binding Proteins; Down-Regulation; Doxorubicin; Esophageal Neoplasms; Esophagus; Fluorescent Antibody Technique; Humans; Hydrogen-Ion Concentration; Leupeptins; Proteasome Inhibitors; Taurochenodeoxycholic Acid; Trans-Activators; Transcription Factors; Tumor Suppressor Proteins

Barrett's esophagus (BE) is a premalignant lesion in which columnar epithelium (containing goblet cells) replaces esophageal squamous cells. Previous evidence suggested that hydrophobic bile acids and zinc deficiency each play a role in BE development. We fed wild-type C57BL/6 mice a zinc-deficient diet containing the hydrophobic bile acid, deoxycholic acid for various times up to 152 days. All mice fed this diet developed esophagitis by 69 days on the diet and 63% of the mice on this diet for 88 to 152 days also developed a BE-like lesion. Esophageal tissues showed thickened mucosa, increased proliferation, and increased expression of markers associated with oxidative and nitrosative stress. The newly formed BE-like lesions expressed Mucin-2, a marker of columnar differentiation. They also showed translocation of the p65 subunit of nuclear factor-kappaB and beta -catenin to the nucleus and typical histological changes associated with BE lesions. This mouse model of esophagitis and BE is expected to contribute to a deeper understanding of BE pathogenesis and to strategies for prevention of BE progression to cancer.

Topics: Animals; Barrett Esophagus; Cell Division; Deoxycholic Acid; Diet; Disease Models, Animal; Disease Progression; Esophagitis; Immunohistochemistry; Male; Mice; Mice, Inbred C57BL; Oxidative Stress; Zinc

Barrett's esophagus (BE) is a premalignant lesion of the distal esophagus in which squamous epithelial cells are replaced by metaplastic intestinal-like columnar epithelium that contains goblet cells. The factors that contribute to the progression from normal squamous mucosa to BE, Barrett's dysplasia, and adenocarcinoma are not well understood at the molecular level. Since reflux of bile acids is associated with BE development, we speculate that cells with an apoptosis-resistant phenotype are selected after long-term repeated exposure to pulses of bile acids. This will result in the survival of cells with unrepaired DNA damage, and a consequent increase in genomic instability leading to cancer progression. The major goal of this study is to compare sensitivity to apoptosis induced by the bile acid, deoxycholate (DOC), a known inducer of apoptosis, in normal esophageal squamous epithelium, normal colon epithelium, and BE.. Thirteen patients with a confirmed diagnosis of BE and four patients who had undergone clinically indicated colectomy were included in the present study. Freshly obtained biopsies were incubated with control medium or medium supplemented with 1 mM DOC for 3 h and then evaluated for apoptotic changes using transmission electron microscopy and immunohistochemical staining for two apoptotic markers, cleaved caspase 3 and cleaved cytokeratin 18.. Our results indicate that BE is resistant to apoptosis induced by DOC compared to esophageal squamous epithelium and normal colon epithelium. In addition, electron micrographs revealed mitochondrial swelling in squamous epithelial cells treated ex vivo with DOC, which was absent in epithelial cells of BE. Formation of swollen mitochondria is an early marker of apoptotic cell death. Altogether, the data indicate that reduced apoptosis capability in BE tissue may contribute to progression to esophageal adenocarcinoma.

Topics: Adult; Aged; Apoptosis; Barrett Esophagus; Biopsy; Caspase 3; Caspases; Colon; Deoxycholic Acid; Epithelium; Esophagus; Humans; Immunohistochemistry; In Vitro Techniques; Intestinal Mucosa; Keratins; Microscopy, Electron, Transmission; Middle Aged

Barrett's oesophagus patients accumulate chromosomal defects during the histological progression to cancer, one of the most prominent of which is the amplification of the whole of chromosome 4. We aimed to study the role that the transcription factor NF-kappaB, a candidate cancer- promoting gene, present on chromosome 4, plays in Barrett's oesophagus, using OE33 cells as a model. Specifically, we wanted to determine if NF-kappaB was activated by exposure to bile acid (deoxycholic acid) in oesophageal cells. We employed pathway specific cDNA microarrays and real-time PCR, to first identify bile acid induced genes and specifically to investigate the role of NF-kappaB. An NF-kappaB reporter system was used, as well as an inhibitor of NF-kappaB (pyrrolidine dithiocarbamate) to confirm the activation of NF-kappaB by bile. We show that physiological levels of DCA (100-300 microM) were capable of activating NF-kappaB in OE33 cells and inducing NF-kappaB target gene expression (particularly IkappaB and IL-8). Other gene expression abnormalities were also shown to be induced by DCA. Importantly, preliminary experiments showed that NF-kappaB activation by bile occurred at neutral pH, but not at acid pH. Acidic bile did however cause over-expression of the c-myc oncogene, as reported previously. Hence, we present data showing that NF-kappaB may be a key mediator of carcinogenesis in bile exposed Barrett's tissues. In addition, neutral bile acids appear to play a significant part in reflux induced gene expression changes. We postulate that the activation of the survival factor NF-kappaB by bile may be linked to the previous cytogenetic data from our laboratory showing the amplification of NF-kappaB's chromosome (chromosome 4), during Barrett's cancer progression. Hence chromosome 4 amplification may provide a survival mechanism for bile exposed oesophageal tissues via NF-kappaB.

Topics: Adenocarcinoma; Barrett Esophagus; Deoxycholic Acid; Esophageal Neoplasms; Esophagus; Gene Expression Regulation, Neoplastic; Humans; I-kappa B Proteins; Interleukin-8; NF-kappa B

To examine the expression of the transcription factor nuclear factor kappa B (NF-kappaB) in Barrett's epithelium and adenocarcinoma and the impact of NF-kappaB expression on tumor stage and response to neoadjuvant chemotherapy and radiation therapy.. Progression of Barrett's esophagus to adenocarcinoma is associated with a wide range of cellular and molecular abnormalities. Nuclear factor-kappa B (NF-kappaB) regulates several genes involved in inflammatory, immune and apoptotic responses, but its role in esophageal inflammation and tumorigenesis has not been reported.. Mobility shift assay was used to measure NF-kappaB activity in nuclear extracts of fresh-frozen biopsies from tumor and uninvolved tissues (n = 30) and esophageal cell lines OE33, SKGT-4, and OE21. RelA expression was assessed by immunohistochemical staining (n = 97). The NF-kappaB/RelA and IkappaB protein expressions were also examined by Western blotting.. NF-kappaB was not expressed in normal esophageal squamous epithelium, in contrast to increased expression in 40% of patients with Barrett's epithelium. Sixty-one percent of resected tumors (n = 97) displayed NF-kappaB immunoreactivity, and 87.5% of the NF-kappaB-positive tumors were Stage IIb and III compared with only 12.5% of patients with Stage I and IIa disease (P < 0.05). The expression of NF-kappaB inversely correlated with major or complete pathologic responses to neoadjuvant chemotherapy and radiation therapy, with 15/20 (75%) responders in the NF-kappaB-negative group compared with 7/38 (18%) in the NF-kappaB-positive group (P < 0.00001). Moreover, incubation of esophageal cell lines OE33, SKGT-4, and OE21 with deoxycholic acid or low pH induced NF-kappaB expression.. Bile acids and low pH induce NF-kappaB expression in esophageal cell lines. NF-kappaB activation is common in esophageal adenocarcinoma. In patients with Barrett's epithelium and an associated esophageal adenocarcinoma, there is a progressive expression of NF-kappaB through Barrett's tumorigenesis. The absence of NF-kappaB expression in esophageal adenocarcinoma correlates with response to neoadjuvant chemoradiotherapy and may be of value in predicting response to neoadjuvant therapy.

Topics: Adenocarcinoma; Antineoplastic Agents; Barrett Esophagus; Bile Acids and Salts; Cell Line, Tumor; Cell Transformation, Neoplastic; Chemotherapy, Adjuvant; Deoxycholic Acid; Esophageal Neoplasms; Esophagectomy; Humans; Hydrogen-Ion Concentration; Neoadjuvant Therapy; Neoplasm Staging; NF-kappa B; Predictive Value of Tests; Radiotherapy, Adjuvant; Survival Analysis; Treatment Outcome

Barrett's oesophagus is an acquired precancerous condition that develops from mucosal injury incurred due to chronic gastro-oesophageal reflux. The aim of this study was to determine if bile and/or acid components of the refluxate can induce DNA damage in vitro. The oesophageal cell lines FLO-1 and HET1-A were exposed to primary bile salts, individually or as a mixture, and the secondary bile salt sodium deoxycholate, in neutral or acidified media. Cells were then examined in the comet assay to measure DNA strand breaks. Cell viability was also monitored. Acidified media induced DNA damage in a pH- and time-dependent manner. The primary bile compounds sodium glycocholate, glycocholic acid, sodium taurocholate and taurochenodeoxycholate, as an equimolar mixture (100 microM), caused a small but significant (P < 0.028) elevation in DNA damage, but only at neutral pH in FLO-1 cells. Sodium deoxycholate (100 microM) caused a significant (P < 0.008) elevation in DNA damage in both cell lines, but again only at neutral pH. These data suggest that specific components of gastro-oesophageal refluxate are capable of causing DNA damage and may participate in the genesis and progression of Barrett's oesophagus via this mechanism.

Topics: Barrett Esophagus; Bile Acids and Salts; Cell Line; Cell Survival; Comet Assay; Deoxycholic Acid; DNA Damage; Esophagus; Gastroesophageal Reflux; Humans; Hydrogen-Ion Concentration

C-myc over expression is implicated in malignancy although to date this has not been studied in Barrett's metaplasia. We sought to determine c-myc expression in the malignant progression of Barrett's metaplasia and whether it may be induced by bile acids seen in gastro-oesophageal refluxate.. C-myc protein and mRNA levels were assessed in 20 Barrett's metaplasia and 20 oesophageal adenocarcinoma samples by western blotting and real time polymerase chain reaction. Levels of c-myc and proliferation were also assessed in cell lines OE21, OE33, SW-480, and TE-7 stimulated with pulses or continuous exposure to the bile acids deoxycholic acid and chenodeoxycholic acid.. C-myc protein was upregulated in 50% of Barrett's metaplasia and 90% of oesophageal adenocarcinoma samples compared with squamous, gastric, and duodenal controls. C-myc immunolocalisation in Barrett's metaplasia revealed discrete nuclear localisation, becoming more diffuse with progression from low to high grade dysplasia to adenocarcinoma. Both continual and pulsed bile acid induced c-myc at pH 4, with no effect at pH 7 or with acidified media alone. Pulsed bile acid treatment induced proliferation (p<0.05); in contrast, continuous exposure led to suppression of proliferation (p<0.05).. We have shown upregulation of c-myc with malignant progression of Barrett's metaplasia and suggest that acidified bile may be a novel agent responsible for induction of this oncogene.

Topics: Adenocarcinoma; Barrett Esophagus; Bile Acids and Salts; Blotting, Western; Cell Division; Chenodeoxycholic Acid; Deoxycholic Acid; Esophageal Neoplasms; Fluorescent Antibody Technique; Gastroesophageal Reflux; Gene Expression Regulation; Genes, myc; Humans; Immunohistochemistry; Polymerase Chain Reaction; Tumor Cells, Cultured; Up-Regulation