Development Of Esophageal Adenocarcinoma Research Articles

Genome-wide tracts of homozygosity and exome analyses reveal repetitive elements with Barrets esophagus/esophageal adenocarcinoma risk

BackgroundBarrett’s esophagus (BE) is most commonly seen as the condition in which the normal squamous epithelium lining of the esophagus is replaced by goblet cells. Many studies show that BE is a predisposing factor for the development of esophageal adenocarcinoma (EAC), a particularly lethal cancer. The use of single nucleotide polymorphisms (SNPs) to map BE/EAC genes has previously provided insufficient genetic information to fully characterize the heterogeneous nature of the disease. We therefore hypothesize that rigorous interrogation of other types of genomic changes, e.g. tracts of homozygosity (TOH), repetitive elements, and insertion/deletions, may provide a comprehensive understanding of the development of BE/EAC.ResultsFirst, we used a case-control framework to identify TOHs by using SNPs and tested for association with BE/EAC. Second, we used a case only approach on a validation series of eight samples subjected to exome sequencing to identify repeat elements and insertion/deletions. Third, insertion/deletions and repeat elements identified in the exomes were then mapped onto genes in the significant TOH regions. Overall, 24 TOH regions were significantly differentially represented among cases, as compared to controls (adjusted-P = 0.002–0.039). Interestingly, four BE/EAC-associated genes within the TOH regions consistently showed insertions and deletions that overlapped across eight exomes. Predictive functional analysis identified NOTCH, WNT, and G-protein inflammation pathways that affect BE and EAC.ConclusionsThe integration of common TOHs (cTOHs) with repetitive elements, insertions, and deletions within exomes can help functionally prioritize factors contributing to low to moderate penetrance predisposition to BE/EAC.

The landscape of selection in 551 esophageal adenocarcinomas defines genomic biomarkers for the clinic.

Esophageal adenocarcinoma (EAC) is a poor prognosis cancer type with rapidly rising incidence. Our understanding of genetic events that drive EAC development is limited, and there are few molecular biomarkers for prognostication or therapeutics. Using a cohort of 551 genomically characterized EACs with matched RNA-seq, we discover 77 EAC driver genes and 21 non-coding driver elements. We identify a mean of 4.4 driver events per tumor, derived more commonly from mutations rather than copy number alterations, and compare these mutations to the exome-wide mutational excess using dN/dS calculations. We observe mutual exclusivity or co-occurrence of events within and between a number of dysregulated EAC pathways, suggestive of strong functional relationships. Poor prognostic indicators (SMAD4, GATA4) are verified in independent cohorts with significant predictive value. Over 50% of EACs contain sensitizing events for CDK4/6 inhibitors, which are highly correlated with clinically relevant sensitivity in a panel EAC cell lines and organoids.

Prevalence and risk factors for Barrett’s esophagus in patients with chronic gastroesophageal reflux disease

Introduction/Objective. The most important complication of gastroesophageal reflux disease (GERD) is Barrett?s esophagus (B?) and the development of esophageal adenocarcinoma. Prevalence of BE is 5?15% in patients with GERD symptoms. The aim of the study was to investigate the prevalence and risk factors for BE in patients with chronic reflux symptoms. A prospective study was conducted in the Clinic of Gastroenterology, Nis Clinical Center. Methods. We included 676 patients with chronic reflux symptoms, who underwent esophagogastroduodenoscopy. The biopsy specimens were obtained in a four-quadrant fashion at intervals of 2 cm from the circumferential endoscopic Barrett?s epithelium in the distal esophagus. BE was diagnosed by pathological examination. Results. Out of the total number patients with GERD, 92 were diagnosed with columnar-lined esophagus (CLE), the prevalence being 13.6%. Histological examination of biopsy from 92 patients with CLE revealed specialized intestinal metaplasia in 15 patients, with the prevalence of 2.22%. Compared to patients without BE, patients with BE were older and more commonly male. Univariable analyses showed that hiatal hernia and Helicobacter pylori infection were two significant risk factors for the onset of esophagitis. The age and the presence of reflux symptoms were associated with the presence of BE. Older age could be considered a significant risk factor for the development of BE and GERD. Conclusion. Prevalence of biopsy-proven BE and CLE in Serbia was 2.22% and 13.6%, respectively, in patients with GERD symptoms.

Antiproliferative and apoptogenic effects of myosmine on erythroleukemia and hepatocellular carcinoma cells

Myosmine, 3-(1-pyrroline-2-yl) pyridine is a minor tobacco alkaloid that has also been found in various widely used foods. Recently, this phytochemical has been gaining an increasing interest as a potential risk factor for the development of oesophageal adenocarcinoma. This study aimed to examine the effects of myosmine on the cell viability and proliferative activity of erythroleukemia and hepatocellular carcinoma cells and to obtain additional information about the mechanisms underlying its cytotoxic activity. The in vitro cytotoxic effect of myosmine on the HepG2 and MEL tumour cell lines was assessed by MTT dye reduction and trypan blue dye exclusion assays. The alterations in the tumour cell morphology induced by myosmine were analysed by fluorescent microscopy after staining with acridine orange (AO)/ethidium bromide (EtBr) and 4′,6-diamidine-2′-phenylindole dihydrochloride (DAPI). Annexin V-FITC/propidium iodide (PI) staining was used to assess the apoptosis-inducing ability of myosmine. The modulating action of antioxidant treatment on myosmine-induced cytotoxicity against the HepG2 tumour cell line was also examined. The cell viability tests indicated that myosmine induced a significant dose-dependent reduction of the viability and proliferative activity of both tumour cell lines. Fluorescent microscopy studies revealed marked alterations in the morphology of myosmine-treated tumour cells with signs of cell cycle arrest and apoptosis. The results of the simultaneous treatment with myosmine and vitamin C showed modulating activity of vitamin C on the cytotoxic effect of myosmine with concentration- and time-dependent variations. The presented results could contribute to the assessment of the potential health risks associated with the dietary myosmine exposure. Abbreviations AO: acridine orange; DAPI: 4‘,6-diamidine-2‘-phenylindole dihydrochloride; DMEM: Dulbecco's modified Eagle medium; DMSO: dimethyl sulfoxide; EtBr: ethidium bromide; FITC: fluorescein isothiocyanate; GERD: gastroesophageal reflux disease; MEL: murine erythroleukemia; MTT: 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide; NNN: N'-nitrosonornicotine; PBS: phosphate buffered saline; PI: propidium iodide

Barrett's esophagus with esophageal adenocarcinoma: risk factors with the current treatment modalities and the journey so far a comprehensive review of the literature

Barrett’s esophagus (BE) is defined as columnar metaplasia of the esophagus a premalignant condition where the esophageal squamous epithelium undergoes columnar changes with metaplasia which predisposes to the development of esophageal adenocarcinoma. Patients with BE are at increased risk for adenocarcinoma which develops in a metaplasia-dysplasia-carcinoma sequence. The definition of BE is still presently a worldwide controversy mainly concerning the diagnostic criteria of BE which histologically requires identifying goblet cells in biopsies. This review focuses on potential key regulators, epigenetic alterations, answer questions on the various controversial issues surrounding the definition, pathogenesis, histopathology, molecular biology, clinical aspects, surveillance, treatments, complications, management of dysplasia and early cancer. As a comprehensive review, it impartially systemizes knowledge from a large number of highly significant publications which describes the molecular and biochemical alterations occurring over BE progression sequence involving multidisciplinary subject from epidemiology, biomarkers, genomics/genetics, gastroenterology, gastrointestinal surgery, and endoscopic therapy.

Upregulation of circulating miR130a is correlated with development of Barrett's esophagus and esophageal adenocarcinoma.

BackgroundBarrett’s esophagus (BE) is one of the major known risk factors for esophageal adenocarcinoma (EAC). Circulating miRNAs are emerging as predictive biomarkers for early detection of malignancy. However, the potential for circulating miRNAs to be used as biomarkers for BE neoplastic progression to EAC has not been well characterized.MethodWe performed a systematic screening approach to identify spectrum miRNAs in the serum of both BE and EAC patients.ResultsmiRNA-array web-based software identified 116 sequences differentially expressed between BE patients and healthy controls. Subsequent study revealed that miR130a was significantly upregulated in serum samples of BE and EAC patients compared to healthy controls. We found an increase in serum miR130a in low-grade and high-grade dysplasia BE patients compared to individuals with metaplasia. We also observed that miR130a expression levels increased gradually from early-stage (I, II) to advanced-stage (III, IV) EAC patients.ConclusionOur preliminary results provide evidence that circulating miR130a is correlated with the development of BE and EAC.

Signatures within the esophageal microbiome are associated with host genetics, age, and disease

BackgroundThe esophageal microbiome has been proposed to be involved in a range of diseases including the esophageal adenocarcinoma cascade; however, little is currently known about its function and relationship to the host. Here, the esophageal microbiomes of 106 prospectively recruited patients were assessed using 16S rRNA and 18S rRNA amplicon sequencing as well as shotgun sequencing, and associations with age, gender, proton pump inhibitor use, host genetics, and disease were tested.ResultsThe esophageal microbiome was found to cluster into functionally distinct community types (esotypes) defined by the relative abundances of Streptococcus and Prevotella. While age was found to be a significant factor driving microbiome composition, bacterial signatures and functions such as enrichment with Gram-negative oral-associated bacteria and microbial lactic acid production were associated with the early stages of the esophageal adenocarcinoma cascade. Non-bacterial microbes such as archaea, Candida spp., and bacteriophages were also identified in low abundance in the esophageal microbiome. Specific host SNPs in NOTCH2, STEAP2-AS1, and NREP were associated with the composition of the esophageal microbiome in our cohort.ConclusionsThis study provides the most comprehensive assessment of the esophageal microbiome to date and identifies novel signatures and host markers that can be investigated further in the context of esophageal adenocarcinoma development.

A435 - Remission of Barrett's Esophagus after Sleeve Gastrectomy, A Case Study

Background: Barrett's Esophagus (BE),common in individuals with gastroesophageal reflux disease (GERD), pre-disposes the affected individual to the potential development of intestinal metaplasia, dysplasia and esophageal adenocarcinoma. Due to physiologic changes incurred post Laparoscopic Sleeve Gastrectomy (LSG), there is an increased risk of BE development, or progression in patients with active GERD. Because of this, many surgeons consider a patient who has BE to be contraindicated for LSG surgery.

Toll-Like Receptor-4 Is a Mediator of Proliferation in Esophageal Adenocarcinoma

Chronic inflammation from reflux disease has been implicated as part of the development of esophageal adenocarcinoma. Toll-like receptors (TLRs), a component of the innate immune system, have been implicated in mediating hyperplasia and metaplasia in response to inflammatory stimuli. Increased TLR4 in human esophageal cancer has been correlated with its carcinogenesis. We hypothesized that TLR4 mediates proliferation of human esophageal adenocarcinoma cells. Normal human esophageal (HET1A) and adenocarcinoma (OE33, FLO-1) cell lines were cultured using standard techniques. TLR4 was measured at baseline and in response to reflux stimuli. All cell lines were treated with the TLR4 agonist lipopolysaccharide for 48 hours, and growth response was measured. Changes in myeloid differentiation primary response 88 (MyD88), tumor necrosis factor receptor associated factor 6 (TRAF6), and nuclear factor-κB (NF-κB) activity were measured during lipopolysaccharide treatment. All cell lines had NF-κB inhibited, and growth rate response was measured. TLR4 was expressed in all cell lines, with increased baseline expression in adenocarcinoma cell lines (p < 0.05). Reflux stimuli increased TLR4 expression (p < 0.01) in normal esophageal cells. After treatment with lipopolysaccharide, all cell lines showed significant increases in proliferation (p < 0.05) due to the NF-κB pathway, and their growth rate was reduced with NF-κB inhibition (p < 0.05). TLR4 is consistently detectable in esophageal cell lines and most highly expressed in adenocarcinoma. TLR4 expression increases in an inflammatory model of reflux disease. TLR4 activation results in increased proliferation due to the TLR4-MyD88-TRAF6-NF-κB signaling pathway, and inhibition of NF-κB leads to decreased esophageal cell growth. These findings suggest TLR4 may be a target to suppress esophageal cancer growth.

Serial Endoscopic Evaluation of Esophageal Disease in a Cancer Model: A Paradigm Shift for Esophageal Adenocarcinoma (EAC) Drug Discovery and Development

A rat model of surgically induced reflux recapitulates the development and progression of human esophageal adenocarcinoma (EAC). In this study, reflux was induced in rats followed by postoperative endoscopy with biopsy, to diagnose and monitor disease progression.Overall, percentage agreement between visual endoscopy and gold standard histology was 95%, with disease-specific classification accuracies of 100% and 75% for Barrett’s with dysplasia and EAC, respectively. Additionally, the percentage agreement for biopsy in tumors >4 mm was 75%. Thereby, establishing endoscopic evaluation as a reliable tool to assess disease progression and provide biopsies for downstream correlates in a de novo EAC model.

Carbonic anhydrases II, IX, and XII in Barrett's esophagus and adenocarcinoma.

The aim of our retrospective study was to investigate the expression and clinical significance of the cancer-associated carbonic anhydrases (CAs) II, IX, and XII in Barrett's esophagus and esophageal adenocarcinoma (EAC). We evaluated 101 archival specimens from patients with EAC as well as seven and 26 samples from patients with high-and low-grade dysplasia, respectively. In addition, normal esophageal squamous epithelium, gastric, and intestinal metaplasia were analyzed when present. The expression patterns of isozymes were detected by immunohistochemistry. CAII and CIX expression levels were lower in the squamous epithelium than in the columnar cells while CAXII showed an opposite pattern and was present mainly in squamous epithelium. Expression patterns in benign, dysplastic, or malignant esophageal columnar lesions were not significantly different. The assessment of clinicopathological associations showed that CAII was significantly downregulated in metastatic disease (p = 0.026). CAIX showed no association with prognosis, although there appeared to be an association (p = 0.056) between high expression and nodal spread. In conclusion, CAII, CAIX, and CAXII do not serve as biomarkers for different phases in the development of EAC.

Inter-institutional variations regarding Barrett's esophagus diagnosis.

Barrett's esophagus (BE) is a known precursor for development of esophageal adenocarcinoma and surveillance of affected patients is necessary when cancer progression risk is considered to be high. However, the accuracy of BE diagnosis may not be homogenous among institutions with endoscopy units. We investigated inter-institutional variability by examining the accuracy of endoscopic diagnosis of BE at 4 different hospitals. The accuracy of BE diagnosis at the 4 hospitals was retrospectively reviewed by 6 expert endoscopists, who independently reviewed endoscopic images of approximately 500 consecutive patients examined at each hospital without information regarding the diagnosis by the on-site endoscopists. When the expert reviewers made different diagnosis, a final diagnosis was made by consensus. That was then compared with the diagnosis of the attending endoscopists at each hospital and their concordance was calculated separately for each endoscopy unit. In addition, the relationship between diagnostic accuracy and endoscopic experience was assessed. The prevalence of BE diagnosis by the on-site endoscopists was not homogenous and varied widely (17.2-96.8%). In 1 hospital, over-diagnosis was the cause of dissimilarity, while under-diagnosis was the cause in two hospitals. Diagnostic accuracy by the attending endoscopists in all 4 hospitals ranged from 44.6 to 83.1% (P < 0.05). There was no significant association between diagnostic accuracy and endoscopic experience or board licensing status of the on-site endoscopists. Diagnostic accuracy for BE was not homogenous among 4 hospitals, and problems related to over- and under-diagnosis should be considered.

Identification of genes and pathways in esophageal adenocarcinoma using bioinformatics analysis.

Esophageal adenocarcinoma (EAC) is one of the most common subtypes of esophageal cancer, and is associated with a low 5-year survival rate. The present study aimed to identify key genes and pathways associated with EAC using bioinformatics analysis. The gene expression profiles of GSE92396, which includes 12 EAC samples and 9 normal esophageal samples, were downloaded from the Gene Expression Omnibus database. Differentially expressed genes (DEGs) between the EAC and normal samples were identified using the limma package in R language. Gene ontology and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses of the identified DEGs were conducted using the online analysis tool, the Database for Annotation, Visualization and Integrated Discovery. A protein-protein interaction (PPI) network of the DEGs was constructed using the Search Tool for the Retrieval of Interacting Genes (STRING) database and Cytoscape software. Finally, module analysis was conducted for the PPI network using the MCODE plug-in in Cytoscape. Of the 386 DEGs identified, the 150 upregulated genes were mainly enriched in the KEGG pathways of complement and coagulation cascades, maturity onset diabetes of the young and protein digestion and absorption; and the 236 downregulated genes were mainly enriched in amoebiasis, retinol metabolism and drug metabolism-cytochrome P450. Based on information from the STRING database, a PPI network comprising of 369 nodes and 534 edges was constructed in Cytoscape. The top 10 hub nodes with the highest degrees were determined as interleukin-8, involucrin, tissue inhibitor of metalloproteinase 1, fibronectin 1, serpin family E member 1, serpin family A member 1, cystic fibrosis transmembrane conductance regulator, secreted phosphoprotein 1, collagen type I alpha 1 chain and angiotensinogen. A total of 6 modules were detected from the PPI network that satisfied the criteria of MCODE score >4 and number of nodes >4. KEGG pathways enriched for the module DEGs were mainly within arachidonic acid metabolism, complement and coagulation cascades and rheumatoid arthritis. In conclusion, identification of these key genes and pathways may improve understanding of the mechanisms underlying the development of EAC, and may be used as diagnostic and therapeutic targets in EAC.

Gastroesophageal reflux and Barrett's esophagus: a pathway to esophageal adenocarcinoma.

The incidence of esophageal adenocarcinoma (EAC) has increased significantly in Western countries. The rising prevalence of gastroesophageal reflux disease (GERD) and obesity has played a major role in the increasing numbers of EAC. Approximately 10-15% of patients with GERD will develop Barrett's esophagus (BE). This metaplastic transformation is due to the chronic injury produced by repeated reflux episodes and involves genetic mutations that can lead to a malignant transformation. Ultimately, the development of EAC is characterized by the sequence BE metaplasia-dysplasia-invasive carcinoma.

Abstract 3077: Krüppel-like factor 5 and its connection to Sonic Hedgehog signaling in Barrett's esophagus and esophageal adenocarcinoma

Abstract Aims: We sought to determine whether KLF5 was involved, at either phenotypic or functional levels, in the genesis and progression of Barrett's esophagus (BE) to esophageal adenocarcinoma (EAC), and whether this involvement was related to sonic hedgehog (SHH) signaling. In human adults, KLF5 is expressed in the less differentiated cells of the intestinal crypts, where its activity promotes cell proliferation, contributes to intestinal epithelial homeostasis, and is necessary for villus formation. KLF5 has been found to be highly active in a number of other cancer types, including gastric cancer; moreover, the known role of KLF5 in intestinal epithelial differentiation may contribute to metaplasia and dysplasia in BE and EAC development. We also sought to ascertain whether KLF5 activity was connected to the sonic hedgehog (SHH) pathway, since this pathway is already known to be highly active in BE and EAC. Methods and results: Quantitative reverse transcriptase PCR (qRT-PCR) performed on RNA obtained from BE cell lines (GhTRT and QhTRT) and EAC cell lines (SKGT4 and OE33) revealed that KLF5 is underexpressed in BE cell lines and overexpressed in EAC cell lines relative to normal primary squamous esophageal epithelial cells (HEEpic). Moreover, qRT-PCR performed on clinical BE and EAC tissue specimens showed the same pattern, with downregulation in BE tissues and upregulation in EAC tissues (relative to matched normal esophageal control tissues). Next, we determined KLF5 functional effects in EAC in vitro. The EAC cell line SKGT4 was transfected with KLF5 siRNA, and WST-1 cell proliferation assays revealed significantly lower cell proliferation at 72 hours (p&amp;lt;0.00005) and 96 hours (p&amp;lt;0.05) after transfection, relative to mock-transfected SKGT4. We then assayed KLF5 downstream effects on esophageal adenocarcinogenesis as well as SHH signaling in vitro. qRT-PCR performed on KLF5-silenced SKGT4 RNA revealed significantly diminished expression (relative to mock-transfected SKGT4) of the following known EAC-related genes: CDX1 (p&amp;lt;0.005), VIL1 (p&amp;lt;0.05), MUC2 (p&amp;lt;0.005), and MUC5ac (p&amp;lt;0.0005); moreover, GLI1, a known SHH pathway target gene, was significantly downregulated by KLF5 inhibition (p&amp;lt;0.005), while PTCH1, a known SHH pathway-inhibitory gene, was significantly upregulated (p&amp;lt;0.05). Conclusion: These tissue phenotypic and in vitro functional data identify KLF5 as a potential oncogene in esophageal adenocarcinogenesis. KLF5 is a potential therapeutic and/or chemopreventive target that can be evaluated in future studies of EAC or BE, such as with metformin, which is known to inhibit KLF5 activity. We also identify a potential new connection between KLF5 and SHH pathway activity in the development of EAC. This potential connection deserves further exploration in other malignancies, as well as in physiologic functions such as human development or adult stem cell maintenance. Citation Format: Christopher K. Ng, Yulan Cheng, John M. Abraham, Stephen J. Meltzer. Krüppel-like factor 5 and its connection to Sonic Hedgehog signaling in Barrett's esophagus and esophageal adenocarcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3077.

PO-172 Role of lithocholic acid-induced cell signalling in oesophageal cancer progression model

IntroductionA p53-checkpoint operates in the development of oesophageal adenocarcinoma (OAC) defined by prevalent TP53 gene mutations in patients with Barrett’s and high-grade dysplasia (HGD). The molecular genetic relationship between OAC and its precursor lesion, Barrett’s oesophagus, is poorly understood. The effective therapeutic targets should focus on early mutations of the disease, which become clonal in the later stage. Mutational context of some specific single nucleotide variants are common throughout the progression of the disease, suggesting exposure to common mutagens throughout the progression course.Material and methodsTP53 null or truncated cell lines were generated by targeting exon 4 of TP53 gene using CRISPR/Cas9 technology. Cell cycle analysis and Annexin V5 stained cells were analysed by FACS after treatment with lithocholic acid (LCA) to recapitulate the reflux of bile acids in OAC. Changes in proteins levels and signalling pathways upon LCA exposure were identified using mass spectrometry and validated with western blotting. Immunohistochemistry (IHC) analysis of OAC and normal tissues was performed to check the expression of identified bile acid-induced genes in tumours.Results and discussionsOesophageal Barrett’s wt-p53 cell line CPA was used to define the effects of TP53 gene ablation on stress responses, cell survival, and mutation rates. FACS analysis revealed TP53 null cells sensitivity towards LCA via apoptotic pathway. Mass spectrometry analysis identified disrupted NDRG1 and TGFβ pathways. SMAD4 driver mutations have previously been reported exclusively to OAC, which provide a clear genetic boundary between OAC and HGD. Western blot analysis after LCA exposure showed increased levels of SMAD4-independent of p53 pathway. SMAD4 depletion in TP53 null cells stimulates cell-migration in the presence of inhibitory levels of LCA, corroborates the role of SMAD4 loss in metastasis. Loss of p53 also upregulates NDRG1 which increases migration in presence of LCA and was found to be a pro-invasive factor. IHC staining of OAC, lymph node and normal tissues showed heterogeneous expression of NDRG1 in tumour, mostly in membrane, suggesting its dynamic expansion on LCA exposure in vivo.ConclusionThe recurrent reflux of bile acids in Barrett’s cells, especially LCA, could sensitise cells to harbour further mutations. LCA induces p53-independent upregulation of SMAD4. Depletion of NDRG1 and SMAD4 in p53 null cells stimulates cell-migration in the presence of LCA, corroborating their role in metastasis.

PO-305 Chromatin accessibility profiling identifies an underlying HNF4A-GATA6 regulatory module in oesophageal adenocarcinoma

IntroductionThe chromatin landscape of mammalian cells underpins their transcriptional profiles, which then dictate fate and function. Mutations within chromatin remodelling genes have been implicated in early oesophageal adenocarcinoma (OAC) development, thus alterations in the chromatin landscape may pose an important molecular step in OAC development. OAC is often lethal, therefore genome-wide, basic research will provide foundations to develop new treatments and patient stratification methods.Material and methodsWe have used Assay for Transposase-Accessible Chromatin using sequencing (ATAC-seq) to profile the accessible chromatin landscape of normal oesophagus and oesophageal adenocarcinoma tissue samples, in addition to representative cell lines. Downstream analysis has involved bioinformatic de novo motif analysis and ATAC-footprinting, Chromatin immunoprecipitation with sequencing (ChIP-seq) and siRNA-mediated knockdowns.Results and discussionsOur results revealed an altered chromatin landscape in cancerous tissue and identified ‘cancer-specific’ regions of accessibility. Using de novo motif discovery methods and footprinting analysis, we have identified enriched transcription factor motifs for GATA6 and HNF4A in differentially accessible regions and footprints. Also, comparison between the chromatin landscape of OAC cell-lines and OAC tissue identified the cell-line that best represents OAC tumours. HNF4A ChIP-seq and GATA6 ChIP-seq data, in oesophageal cancer cells, shows co-occupancy of HNF4A and GATA6 at 90% of sites and confirm motif enrichment and footprint observations. HNF4A and GATA6 knockdown experiments demonstrate overlap of gene regulation and also identify genes that are exclusively regulated by the presence HNF4A and GATA6. Importantly, genes directly regulated by HNF4A or GATA6 are on average overexpressed in OAC, however genes regulated by both factors are more overexpressed by 2-fold.ConclusionOur data demonstrate the power of ATAC-seq in genome-wide discovery methods and we have identified a novel HNF4A-GATA6 transcription network that is active in OAC.

Conjugated Bile Acids Promote Invasive Growth of Esophageal Adenocarcinoma Cells and Cancer Stem Cell Expansion via Sphingosine 1-Phosphate Receptor 2–Mediated Yes-Associated Protein Activation

Esophageal adenocarcinoma (EAC) is the sixth leading cause of cancer deaths worldwide and has been dramatically increasing in incidence over the past decade. Gastroesophageal reflux and Barrett esophagus are well-established risk factors for disease progression. Conjugated bile acids (CBAs), including taurocholate (TCA), represent the major bile acids in the gastroesophageal refluxate of advanced Barrett esophagus and EAC patients. Our previous studies suggested that CBA-induced activation of sphingosine 1-phosphate receptor 2 (S1PR2) plays a critical role in promoting cholangiocarcinoma cell invasive growth. However, the role of CBAs in EAC development and underlying mechanisms remains elusive. In the current study, we identified that the expression level of S1PR2 is correlated to invasiveness of EAC cells. TCA significantly promoted cell proliferation, migration, invasion, transformation, and cancer stem cell expansion in highlyinvasive EAC cells (OE-33 cells), but had less effect on the lower invasive EAC cells (OE-19 cells). Pharmacologic inhibition of S1PR2 with specific antagonist JTE-013 or knockdown of S1PR2 expression significantly reduced TCA-induced invasive growth of OE-33 cells, whereas overexpression of S1PR2 sensitized OE-19 cells to TCA-induced invasive growth. Furthermore, TCA-induced activation of S1PR2 was closely associated with YAP and β-catenin signaling pathways. In conclusion, CBA-induced activation of the S1PR2 signaling pathway is critically involved in invasive growth of EAC cells and represents a novel therapeutic target for EAC.

Su1118 APPEARANCE OR PROGRESSION OF DYSPLASIA AND CANCER IN BARRETT’S ESOPHAGUS UNDERGOING RADIOFREQUENCY ABLATION

Barrett’s esophagus (BE) is a known risk factor for esophageal adenocarcinoma (EAC). Radiofrequency ablation (RFA) has been associated with a high rate of complete eradication for dysplasia and intestinal metaplasia. Data are limited on patients who have progression of dysplasia or development of EAC while undergoing RFA therapy. We aimed to better characterize these patients. This was a retrospective review of medical records at a tertiary academic medical center. We included patients with at least one RFA treatment for BE without EAC. Patients achieving complete eradication of dysplasia were excluded. Data collected included demographics, date of BE diagnosis, endoscopy findings, anatomic pathology, location of the newly developed dysplasia, length of BE, RFA adjuvant therapies, and date of death. A total of 475 patients underwent RFA, of which 39 (8.2%) progressed to low grade dysplasia (LGD), high grade dysplasia (HGD) or EAC while undergoing therapy. The distribution of these changes is depicted in Table 1. Only 1 patient was female. Patient demographic data is found in Table 2. For those with HGD receiving RFA, 12.6% progressed into cancer. The majority of cancer developed in the distal esophagus (13/23 = 56.5 %). Seven patients (30.4 %) had their original HGD distributed over the entire BE segment prior to initial RFA. The progression was observed after an average of 3.0 RFA sessions. Twenty patients had endoscopic mucosal resection (EMR) and 2 had esophagectomy. Four (17.4 %) patients died. Eight patients achieved complete remission of intestinal metaplasia. For those who underwent RFA for LGD, 6 patients progressed to cancer and 6 to HGD. The rate of progression into cancer was significantly lower (5.1%) than those undergoing treatment for HGD (12.6%) (p= 0.04). The average number of RFA sessions before progression was 2.6. All 6 developed cancer in the distal BE segment and 5 of these patients had original low grade dysplasia in the distal BE segment. All 6 patients received adjuvant EMR and 2 esophagectomy. Two of these patients died. The 2 patients with short segment BE (2cm and 2.75 cm) progressed to cancer. Of the 4 patients with non-dysplastic Barrett’s who progressed while receiving RFA, the dysplasia appeared in the distal BE segment in 2, in the proximal in 1 and in the mid distal in 1. One patient developed cancer, but ultimately achieved complete remission of intestinal metaplasia. Our study shows that 8.2% of patients receiving RFA for BE have progression of dysplasia or development of cancer. Those at highest risk for progression are patients initially treated for HGD with 12.6% progressing to cancer after an average of 3.0 RFA sessions. Further studies are needed to determine why this progression occurred and how it can be avoided.Tabled 1Table 1. Number of patients with progression of dysplasia or progression to cancer based on initial indication for RFA therapy.Progression to:RFA for NDBE/ID (175)RFA for LGD (117)RFA for HGD (183)Indefinite DysplasiaLow grade Dysplasia1High Grade Dysplasia26Cancer16*23*Total4 (2.3%)12 (10.3%)23 (12.6%)Abbreviations: non-dysplastic Barrett’s esophagus (NDBE), indefinite dysplasia (ID), low grade dysplasia (LGD), high grade dysplasia (HGD). *P = 0.04 for progression into cancer between LGD and HGD groups Open table in a new tab Tabled 1Table 2. Characteristics of patients who had progression of dysplasia or development of cancer after RFA.RFA for NDBE/IDRFA for LGDRFA for HGDMean Age First Dysplasia or Mean Age First BE for NDBE (Range)64.5 (60-74)68.5 (54-78)72.3 (52-84)Mean Age Diagnosis Highest Progression (Range)68.5 (61-76)71.6 (57-81)74.2 (52-82)Mean Length BE Segment cm (Range)3.8 (2-5)7.0 (2-17)7.0 (1-14)Mean Number RFA Sessions Before Progression (Range)2.0 (1-3)2.6 (1-5)3.0 (1-11)Original Site of Dysplasia in Barrett’s Segment Before RFANAProximal11Proximal Mid10Mid04Mid Distal11Distal67Entire27Unknown13Site of Progression In EsophagusProximal124Proximal Mid003Mid023Mid Distal110Distal2713Adjuvant TherapyEMR2720ESD001Chemo-radiation002Brachytherapy002Esophagectomy022Cryotherapy123Radiation001Rate of CRIM128Deaths114Abbreviations: non-dysplastic Barrett’s esophagus (NDBE), indefinite dysplasia (ID), low grade dysplasia (LGD), high grade dysplasia (HGD), not applicable (NA), complete remission of intestinal metaplasia (CRIM). Open table in a new tab

Clinical Guidelines Update on the Diagnosis and Management of Barrett's Esophagus.

Barrett's esophagus is a condition in which metaplastic columnar epithelium replaces stratified squamous epithelium in the distal esophagus. This condition occurs due to chronic gastroesophageal reflux disease and is a risk factor for the development of esophageal adenocarcinoma. Multiple clinical guidelines have been published around the world in recent years to assist gastroenterologists in the management of these patients and have evolved as new data have become available. While some information such as surveillance technique has not drastically changed, there has been an evolution over the years in diagnostic criteria, screening and endoscopic therapy with a variety of subtle differences among the different guidelines. Herein, we highlight areas of agreement and disagreement on definitions, screening, surveillance, and treatment techniques among these guidelines for the optimal management of Barrett's esophagus patients.