Pathogenesis Of Esophageal Adenocarcinoma Research Articles

Abstract 555: Role of TRIM31 in the pathogenesis of esophageal adenocarcinoma

Abstract Background: Esophageal adenocarcinoma (EAC) is one the deadliest cancers in United States (US) and the only major cancer in the US with increasing incidence. Gastroesophageal reflux disease (GERD) can cause Barrett’s esophagus (BE), a columnar metaplasia of the esophagus strongly associated with the development of EAC. GERD leading to BE is a common pre-occurrence in EAC patients, but the mechanism remains obscure. To explore the mechanism and its components, we compared gene expression in BE and EAC cells with normal esophageal cells and found high expression of tripartite motif-containing protein 31 (TRIM31) in BE and EAC compared to normal esophagus (NE) by transcriptomic profiling of RNA extracted from human esophageal tissues. E3 ubiquitin ligase TRIM 31 is a new member of TRIM family and it has been reported to have oncogenic potentials in some cancers. However, its role in EAC pathogenesis is yet to be understood. Methods: RNA sequencing and transcriptomic profiling were performed on human NE, BE, and EAC epithelial tissue samples. TRIM31 expression in NE cell line (Het-1A) and EAC cell lines (OE19, Flo-1, OE33, SK-GT-2, and OACM5.1C) were identified by Western blot analysis. The Het-1A cell line, after exposure to acidic pH and bile acids, was assessed for variable TRIM31 expression. Cell morphology and viability analyses of NE and EAC cell lines after exposure to acidic pH and bile acids either alone or in combinations were observed by microscopy and WST-1 assay respectively. Results: Transcriptomic analysis showed that BE and EAC are similar in their differential gene expression with upregulation of the TRIM31 compared to that in NE. Concordant with their columnar phenotype, BE and EAC groups displayed a multitude of differentially expressed genes relative to NE samples; however, less differentially expressed genes were found comparing BE and EAC groups. Western blot demonstrated frequent overexpression of TRIM31 in EAC cell lines with very low expression of TRIM31 in NE epithelial cell line. When NE epithelial cell line Het-1A was exposed to acidic pH as well as bile acids in acidic pH, we saw a change in cell morphology that may correlate with the metaplasia of these cells to more resilient forms, as seen in human BE and EAC. Interestingly, bile acids in acidic pH increased TRIM31 expression in NE cell line Het-1A. Bile acids had a greater effect on decreasing cell viability at high concentrations and that effect is enhanced when bile acids were added in acidic pH. WST-1 cell viability assay revealed that EAC cells were more resistant to bile acids as well as bile acids in acidic pH induced decreased in cell viability compared to that in NE cell line Het-1A. The sustained cell viability of EAC cell lines under these harsh conditions correlates with the upregulation of TRIM31. Conclusions: Thus, TRIM31 may be an important oncogenic factor in GERD-induced EAC development and may be an innovative therapeutic target and marker for EAC. Citation Format: Md Sazzad Hassan, Jesse Mast, Annie Ritter, Saisantosh Ponna, Niranjan Awasthi, Urs von Holzen. Role of TRIM31 in the pathogenesis of esophageal adenocarcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 555.

MiRNA profiling of esophageal adenocarcinoma using transcriptome analysis.

Esophageal adenocarcinoma (EAC) occurs following a series of histological changes through epithelial-mesenchymal transition (EMT). A variable expression of normal and aberrant genes in the tissue can contribute to the development of EAC through the activation or inhibition of critical molecular signaling pathways. Gene expression is regulated by various regulatory factors, including transcription factors and microRNAs (miRs). The exact profile of miRs associated with the pathogenesis of EAC is largely unknown, though some candidate miRNAs have been reported in the literature. To identify the unique miR profile associated with EAC, we compared normal esophageal tissue to EAC tissue using bulk RNA sequencing. RNA sequence data was verified using qPCR of 18 selected genes. Fourteen were confirmed as being upregulated, which include CDH11, PCOLCE, SULF1, GJA4, LUM, CDH6, GNA12, F2RL2, CTSZ, TYROBP, and KDELR3 as well as the downregulation of UGT1A1. We then conducted Ingenuity Pathway Analysis (IPA) to analyze for novel miR-gene relationships through Causal Network Analysis and Upstream Regulator Analysis. We identified 46 miRs that were aberrantly expressed in EAC compared to control tissues. In EAC tissues, seven miRs were associated with activated networks, while 39 miRs were associated with inhibited networks. The miR-gene relationships identified provide novel insights into potentially oncogenic molecular pathways and genes associated with carcinogenesis in esophageal tissue. Our results revealed a distinct miR profile associated with dysregulated genes. The miRs and genes identified in this study may be used in the future as biomarkers and serve as potential therapeutic targets in EAC.

The Role of Microbiota in the Pathogenesis of Esophageal Adenocarcinoma.

Simple SummaryEsophageal adenocarcinoma has a poor 5-year survival rate and is among the highest mortality cancers. Changes in the esophageal microbiome have been associated with cancer pathogenesis; however, the molecular mechanism remains obscure. This review article critically analyzes the molecular mechanisms through which microbiota may mediate the development and progression of esophageal adenocarcinoma and its precursors-gastroesophageal reflux disease and Barrett’s esophagus. It summarizes changes in esophageal microbiome composition in normal and pathologic states and subsequently discusses the role of altered microbiota in disease progression. The potential role of esophageal microbiota in protecting against the development of esophageal adenocarcinoma is also discussed. By doing so, this article highlights specific directions for future research developing microbiome-mediated therapeutics for esophageal adenocarcinoma.Esophageal adenocarcinoma (EAC) is associated with poor overall five-year survival. The incidence of esophageal cancer is on the rise, especially in Western societies, and the pathophysiologic mechanisms by which EAC develops are of extreme interest. Several studies have proposed that the esophageal microbiome may play an important role in the pathophysiology of EAC, as well as its precursors—gastroesophageal reflux disease (GERD) and Barrett’s esophagus (BE). Gastrointestinal microbiomes altered by inflammatory states have been shown to mediate tumorigenesis directly and are now being considered as novel targets for both cancer treatment and prevention. Elucidating molecular mechanisms through which the esophageal microbiome potentiates the development of GERD, BE, and EAC will provide a foundation on which new therapeutic targets can be developed. This review summarizes current findings that elucidate the molecular mechanisms by which microbiota promote the pathogenesis of GERD, BE, and EAC, revealing potential directions for additional research on the microbiome-mediated pathophysiology of EAC.

Identification of TLR2 Signalling Mechanisms Which Contribute to Barrett's and Oesophageal Adenocarcinoma Disease Progression.

Simple SummaryOesophageal adenocarcinoma (EAC) is a common type of oesophageal cancer with a rapidly rising incidence. Risk factors such as reflux, smoking, obesity and Barrett’s oesophagus cause chronic irritation and inflammation in the oesophagus. A receptor that causes inflammation, called Toll-like receptor 2 (TLR2), is expressed at higher levels in oesophageal cells from patients with Barrett’s and EAC, compared to disease-free patients. This study aimed to identify mechanisms involved in TLR2-mediated inflammation in oesophageal cells; and to assess whether TLR2 represents a therapeutic target to limit EAC development. Findings reveal that TLR2 activation in Barrett’s organoids and oesophageal cancer cells amplifies inflammation and promotes cancer development by causing the secretion of several inflammatory factors, most notably the nuclear protein, HMGB1. We demonstrate that TLR2 neutralisation efficiently blocks the inflammatory effects of TLR2 in these systems, revealing the therapeutic potential of TLR2 targeting to limit oesophageal disease and cancer progression.Chronic inflammation plays an important role in the pathogenesis of oesophageal adenocarcinoma (EAC) and its only known precursor, Barrett’s oesophagus (BE). Recent studies have shown that oesophageal TLR2 levels increase from normal epithelium towards EAC. TLR2 signalling is therefore likely to be important during EAC development and progression, which requires an inflammatory microenvironment. Here, we show that, in response to TLR2 stimulation, BE organoids and early-stage EAC cells secrete pro-inflammatory cytokines and chemokines which recruit macrophages to the tumour site. Factors secreted from TLR2-stimulated EAC cells are shown to subsequently activate TLR2 on naïve macrophages, priming them for inflammasome activation and inducing their differentiation to an M2/TAM-like phenotype. We identify the endogenous TLR2 ligand, HMGB1, as the factor secreted from EAC cells responsible for the observed TLR2-mediated effects on macrophages. Our results indicate that HMGB1 signalling between EAC cells and macrophages creates an inflammatory tumour microenvironment to facilitate EAC progression. In addition to identifying HMGB1 as a potential target for early-stage EAC treatment, our data suggest that blocking TLR2 signalling represents a mechanism to limit HMGB1 release, inflammatory cell infiltration and inflammation during EAC progression.

Abstract 3604: Identification of genes involved in pathogenesis of esophageal adenocarcinoma using RNA sequencing from laser capture micro-dissected formalin-fixed paraffin-embedded tissue specimens

Abstract Esophageal adenocarcinoma (EAC) is one of the most aggressive human cancers and the only major cancer in the United States with increasing incidence. The overall 5-year survival rate of EAC is below 20 percent and treatment remains largely ineffective due to the high resistance to chemotherapy, despite recent advances in systemic treatment options as well as surgical techniques. Gastroesophageal reflux disease (GERD) causes Barrett's esophagus (BE), a columnar metaplasia containing goblet cells of the esophagus strongly associated with the development of EAC. However, the mechanisms driving EAC development remains poorly understood. In this study, transcriptomic profiling was performed using RNA-sequencing (RNA-seq) on normal, premalignant Barrett's and malignant adenocarcinoma esophageal tissues for better understanding the pathogenesis of EAC. Pure population of cells were collected by laser capture microdissection (LCM) of histologically confirmed formalin-fixed paraffin-embedded (FFPE) esophageal tissues. Total RNA was extracted from micro-dissected sections using the Ambion RecoverAll kit followed by RNA quality assessment using Bioanalyzer to determine the RNA integrity number (RIN) and DV200 metric. 15 RNA samples with sufficient purity and appropriate concentrations were sent for library preparations and sequenced on an Illumina NextSeq500. Differential gene expression and network analysis methods were then applied to discover novel driver genes and pathways for EAC development. Clustering for RNA-seq data shows nice clustering of normal esophagus (NE), Barrett's esophagus (BE) and esophageal adenocarcinoma (EAC) samples in relation to gene expression patters. Comparing differentially expressed genes using FDR<0.001 we found many genes differentially expressed, especially between each of the BE and EAC when compared to the NE. Interestingly, there are much less differentially expressed genes when comparing each of the BE and EAD to each other. This shows that BE and EAC are closer to each other than to the normal esophagus, but there are still key differences between them. Using pathway analysis and functional annotation we have identified differentially expressed candidate genes and pathways in BE and EAC involving quite a few pathways including PI3 kinase, focal adhesion kinase and metabolic pathways. In summary, this transcriptomic profiling will improve our understanding of EAC pathogenesis and these candidate genes could be diagnostic and therapeutic targets for EAC. Citation Format: Matthew Guggenbiller, Md Sazzad Hassan, Min Yan, Jun Li, Victoria Makuru, Urs von Holzen. Identification of genes involved in pathogenesis of esophageal adenocarcinoma using RNA sequencing from laser capture micro-dissected formalin-fixed paraffin-embedded tissue specimens [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 3604.

Corrigendum: Discovery of Novel and Clinically Relevant Markers in Formalin-Fixed Paraffin-Embedded Esophageal Cancer Specimen.

[This corrects the article DOI: 10.3389/fonc.2018.00157.].

Elucidating the pathogenesis of esophageal adenocarcinoma through meta-analysis of public data.

71 Background: Esophageal adenocarcinoma (EAC) is the sixth most common cause of cancer-related deaths worldwide. It commonly arises in the setting of reflux disease and Barett’s esophagus. It remains incurable and holds a poor prognosis. Dissecting the genetic signature of EAC can pave new therapeutic avenues. Methods: We employed our Search Tag Analyze Resource (STARGEO) platform to conduct meta-analysis using the National Center for Biotechnology’s (NCBI) Gene Expression Omnibus (GEO). We tagged 151 tumor samples from EAC patients and 62 normal esophageal samples as a control. We then analyzed the signature in Ingenuity Pathway Analysis, restricting genes that showed statistical significance (p < 0.05) and an absolute experimental log ratio greater than 0.15 between tumor and control. Results: Our analysis revealed granulocyte adhesion and diapedesis and FXR/RXR signaling as top canonical pathways. TGFB1, TNF, and beta-estradiol were top upstream regulators with predicted activation. TGFB1 and TNF expression have been correlated with poor prognosis in EAC. Also, beta-estradiol has tumorigenic activity in several cancers but has not been investigated in EAC. Among the top upregulated genes were oncogenic genes such as tetraspanin 8, the antiapoptotic factor OLFM4, and the protease cathepsin E (CTSE). SPINK1, a trypsin inhibitor with recently suggested role in cancer, and the choline transporter SLC44A4, a drug target for pancreatic cancer, were also upregulated. The most downregulated genes included alcohol dehydrogenase 7, associated with EAC in alcohol-drinkers, and the pro-apoptotic gene CRCT1. We also found downregulation of the serine peptidase inhibitor SPINK7. SPINK7 is involved in maintaining epithelial-barrier integrity and is implicated in eosinophilic esophagitis pathogenesis. Lastly, there was downregulation of the candidate tumor suppressor gene transglutaminase 3. Conclusions: Despite screening efforts, EAC incidence and mortality continues to increase as does the need for better treatment. This meta-analysis defines the significant gene expression changes within causal disease processes to provide markers for detection, prognostic insight, and therapeutic value for EAC.

Discovery of Novel and Clinically Relevant Markers in Formalin-Fixed Paraffin-Embedded Esophageal Cancer Specimen.

Due to the ineffectiveness of chemoradiation and targeted therapy in esophageal anticancer care and the subsequent low survival rates, we constructed a high throughput method to discover and investigate new markers with prognostic, diagnostic, and therapeutic clinical utility. This was accomplished by developing a quick, inexpensive, and dependable platform to simultaneously quantify thousands of proteins which subsequently revealed novel markers involved in the pathogenesis of esophageal adenocarcinoma (EAC) via discovery mass spectrometry paired with conservative biostatistics. Our method uncovered a perfect storm of tumor suppressors being downregulated, proliferation markers ramped up, and chemoresistance markers overexpressed—many of which could serve as new therapy targets for EAC. The 12 markers discovered by this method are novel regarding their involvement in the pathogenesis of EAC. The molecular oncology arena now has a dozen new proteomic targets suitable for validation and elucidation of their clinical utility via gene knockdown in cellular and animal models. This new method can be replicated and applied to other cancers or disease states for research and development and discovery-based investigations. Our findings, which serve as a proof of concept, will hopefully motivate research groups to further expound on the molecular processes involved in the aggressiveness of EAC and other solid tumor diseases, ultimately leading to improved patient management strategies.

The Association between O(6)-Methylguanine DNA Methyltransferase (MGMT) rs11016879 and rs7069143 Polymorphisms and Susceptibility to Еsophageal Аdenocarcinoma in a Han Chinese Population

Some evidence has shown that O(6)-methylguanine DNA methyltransferase (MGMT) plays a key role in the pathogenesis of Esophageal Adenocarcinoma (EA) in some populations but not Chinese Han. The objective of this study is to investigate this issue. Three SNPs (rs11016879, rs7069143, rs7071825) were genotyped in 205 unrelated EA patients and 216 healthy controls matched for age and gender using pre-designed TaqMan SNP genotyping assay kits on an ABI PRISM 7900 HT Sequence Detection System. Meanwhile, expression level of MGMT was measured by quantitative real-time reverse-transcription polymerase chain reaction (RT-PCR), including 102 patients for EA and 113 healthy controls. The alleles distribution of rs11016879 (G/A, OR = 1.412, 95% CI = 1.053–1.894, P = 0.021) and the genotypes distribution of rs7069143 (CC/CT, OR = 1.580, 95% CI = 1.047–2.384, P = 0.029) significantly differed between the case and control groups. The expression level of MGMT significantly reduced in patients (control, 0.963 ± 0.094; case, 0.586 ± 0.083; P = 0.022), which was correlated with an increased risk for EA. These findings indicated that the association between MGMT and EA might exist in Chinese Han.

Esophageal Cancer: Genomic and Molecular Characterization, Stem Cell Compartment and Clonal Evolution.

Esophageal cancer (EC) is the eighth most common cancer and is the sixth leading cause of death worldwide. The incidence of histologic subtypes of EC, esophageal adenocarcinoma (EAC) and esophageal squamous carcinoma (ESCC), display considerable geographic variation. EAC arises from metaplastic Barrett’s esophagus (BE) in the context of chronic inflammation secondary to exposure to acid and bile. The main risk factors for developing ESCC are cigarette smoking and alcohol consumption. The main somatic genetic abnormalities showed a different genetic landscape in EAC compared to ESCC. EAC is a heterogeneous cancer dominated by copy number alterations, a high mutational burden, co-amplification of receptor tyrosine kinase, frequent TP53 mutations. The cellular origins of BE and EAC are still not understood: animal models supported a cellular origin either from stem cells located in the basal layer of esophageal epithelium or from progenitors present in the cardia region. Many studies support the existence of cancer stem cells (CSCs) able to initiate and maintain EAC or ESCC. The exact identification of these CSCs, as well as their role in the pathogenesis of EAC and ESCC remain still to be demonstrated. The reviewed studies suggest that current molecular and cellular characterization of EAC and ESCC should serve as background for development of new treatment strategies.

Dysregulation of WNT5A/ROR2 Signaling Characterizes the Progression of Barrett-Associated Esophageal Adenocarcinoma.

The mechanism underlying the progression of normal esophageal mucosa to esophageal adenocarcinoma remains elusive. WNT5A is a noncanonical WNT, which mainly functions via the receptor tyrosine kinase-like orphan receptor 2 (ROR2), and has an unclear role in carcinogenesis. In this study, we aimed to determine the role of WNT5A/ROR2 signaling in esophageal adenocarcinoma. Analysis of WNT5A and ROR2 expression patterns in healthy controls, Barrett and esophageal adenocarcinoma patients' esophageal clinical specimens as well as in various esophageal cell lines demonstrated a ROR2 overexpression in esophageal adenocarcinoma tissues compared with Barrett and healthy mucosa, whereas WNT5A expression was found significantly downregulated toward esophageal adenocarcinoma formation. Treatment of esophageal adenocarcinoma OE33 cells with human recombinant WNT5A (rhWNT5A) significantly suppressed proliferation, survival, and migration in a dose-dependent fashion. rhWNT5A was found to inhibit TOPflash activity in ROR2 wild-type cells, whereas increased TOPflash activity in ROR2-knockdown OE33 cells. In addition, ROR2 knockdown alone abolished cell proliferation and weakened the migration properties of OE33 cells. These findings support an early dysregulation of the noncanonical WNT5A/ROR2 pathway in the pathogenesis of esophageal adenocarcinoma, with the loss of WNT5A expression together with the ROR2 overexpression to be consistent with tumor promotion. The dysregulation of WNT5A/ROR2 noncanonical WNT signaling in Barrett-associated esophageal adenocarcinoma introduces possible prognostic markers and novel targets for tailored therapy of this malignancy. Mol Cancer Res; 14(7); 647-59. ©2016 AACR.

Epigenetics in the Pathogenesis of Esophageal Adenocarcinoma.

Epigenetic influences, such as DNA methylation, histone acetylation, and up-regulation/down-regulation of genes by microRNAs, change the genetic makeup of an individual without affecting DNA base-pair sequences. Indeed, epigenetic changes play an integral role in the progression from normal esophageal mucosa to Barrett's esophagus to esophageal adenocarcinoma via dysplasia-metaplasia-neoplasia sequence. Many genes involved in esophageal adenocarcinoma display hypermethylation, leading to their down-regulation. The classes of these genes include cell cycle control, DNA and growth factor repair, tumor suppressors, antimetastasis, Wnt-related genes, and proapoptotic genes. Histone acetylation in the pathophysiology of esophageal diseases has not been thoroughly investigated, and its critical role in the development of esophageal adenocarcinoma is less defined. Many microRNAs have been associated with the development of Barrett's esophagus and esophageal adenocarcinoma. Here, we critically addressed the specific steps most closely influenced by microRNAs in the progression from Barrett's esophagus to esophageal adenocarcinoma. However, microRNAs can target up to hundreds of genes, making it difficult to correlate directly with a given phenotype of the disease. Esophageal adenocarcinoma progressing from premalignant condition of Barrett's esophagus carries an extremely poor prognosis. Risk stratification for patients based on their epigenetic profiles may be useful in providing more targeted and directed treatment to patients.

Targeting chemokine pathways in esophageal adenocarcinoma

Esophageal adenocarcinoma (EAC) is one of the fastest growing malignancies in the US and needs newer therapeutic and diagnostic strategies. Chronic inflammation plays a role in the pathogenesis of EAC and contributes to the dysplastic conversion of normal esophageal epithelium to Barrett's esophagus and frank adenocarcinoma. Chemokines play important roles in mediating inflammation and recent evidence implicates these ligands and their receptors in the development and spread of various tumors. We demonstrated that the chemokines IL8, CXCL1 and CXCL3 are significantly overexpressed during esophageal carcinogenesis and accompanied by amplification and demethylation of the chr4q21 gene locus. We also demonstrated that IL8 levels can be detected in serum of patients with EAC and can serve as potential biomarkers. We now demonstrate that inhibition of IL8 receptor, CXCR2, leads to decreased invasiveness of esophageal adenocarcinoma derived cells without affecting cellular proliferation. Taken together, these studies reveal the important roles that chemokines play in development of esophageal cancer and demonstrate that these pathways can serve as potential therapeutic targets.

Reflux composition influences the level of NF-κB activation and upstream kinase preference in oesophageal adenocarcinoma cells.

Oesophageal adenocarcinoma (OA) incidence is rising and prognosis is poor. Understanding the molecular basis of this malignancy is key to finding new prevention and treatment strategies. Gastroesophageal reflux disease is the primary cause of OA, usually managed with acid suppression therapy. However, this often does little to control carcinogenic bile acid reflux. The transcription factor nuclear factor kappa B (NF-κB) plays a key role in the pathogenesis of OA and its activity is associated with a poor response to chemotherapy, making it an attractive therapeutic target. We sought to decipher the role of different bile acids in NF-κB activation in oesophageal cell lines using short, physiologically relevant exposure times. The effect of an acidic or neutral extracellular pH was investigated concurrently, to mimic in vivo conditions associated with or without acid suppression. We found that some bile acids activated NF-κB to a greater extent when combined with acid, whereas others did so in its absence, at neutral pH. The precise composition of an individual's reflux, coupled with whether they are taking acid suppressants may therefore dictate the extent of NF-κB activation in the oesophagus, and hence the likelihood of histological progression and chemotherapy success. Regardless of pH, the kinase inhibitor of κB kinase was pivotal in mediating reflux induced NF-κB activation. Its importance was confirmed further as its increased activation was associated with histological progression in patient samples. We identified further kinases important in acid or bile induced NF-κB signalling in oesophageal cells, which may provide suitable targets for therapeutic intervention.

Increased Toll-like receptor 5 expression indicates esophageal columnar dysplasia

Toll-like receptor 5 (TLR5) is an immune receptor, which recognizes bacterial flagellin. Increased expression has been reported in various premalignant and malignant lesions indicating a role in carcinogenesis. We assessed the expression of TLR5 in normal esophageal squamous epithelium, Barrett's esophagus with and without dysplasia, and in esophageal adenocarcinoma. Specimens with normal esophagus (n=93), gastric (n=75) or intestinal metaplasia (n=53) without dysplasia, and low-grade (n=56) or high-grade dysplasia (n=33) and esophageal adenocarcinoma (n=94) were studied. TLR5 immunohistochemical stainings were analyzed for the proportion of positive cells and the intensity of expression. In normal squamous epithelium, only the basal third showed TLR5 expression. In esophageal gastric or intestinal metaplasia, expression was present in majority of the cells but significantly weaker (p<0.001) than in dysplastic epithelium. In dysplasia, expression extended to the apical cytoplasm, contrasting basolateral expression in non-dysplastic columnar epithelium. Receiver operating characteristic curve analysis showed that moderate to high expression intensity of TLR5 indicates low-grade dysplasia with 86 % sensitivity and 83 % specificity. Carcinomas showed increased expression in comparison with non-dysplastic columnar epithelium, but there was no association with prognosis. Our results indicate that the esophageal columnar dysplasia is associated with clear increase of TLR5 expression and dissolution of regular polarized expression. TLR5 staining provides a possible biomarker for the recognition of low-grade dysplasia. In addition, the findings suggest a role for abnormal expression of TLR5 in the pathogenesis of esophageal adenocarcinoma and suggest importance of altered microbiome in the pathogenesis of complications of Barrett's esophagus.

Abstract 3336: The role of Notch signaling in esophageal adenocarcinoma

Abstract Background: The Notch signaling pathway plays a critical role in embryonic development and carcinogenesis. Aberrant Notch signaling has been linked to a wide variety of cancers. Activation of Notch pathway can either suppress or promote tumors depending on the cell type and context. However, the role of the Notch pathway in the pathogenesis and development of esophageal adenocarcinoma (EAC) is poorly understood. Objective: Elucidate the role of NOTCH signaling pathway in EAC. Methodology: In this study, the expression of Notch components in EAC tissues, matched non-tumor esophageal mucosa and normal esophagus tissues, EAC cell lines (FLO-1, JH-EsoAd1, OE19 and OE33) and 3 primary esophageal normal epithelial cells were assessed by quantitative RT- PCR, western blot analysis, immunofluorescence and immunohistochemistry. The effect of blocking as well as ectopic activation of the Notch pathway on the proliferation, colony formation, and gene expression were also characterized. Results: The aberrant activation of Notch signaling was observed in human EAC clinical samples. Expression of most Notch pathway components was elevated in EAC. The expression of activated NOTCH1 also associated with the differentiation grade of EAC. We found that blocking Notch activity by gamma-secretase inhibitors(GSI) affects the proliferation and/or survival of EAC cell lines and human EAC samples ex vivo cultures. In contrast, this effect was not observed in human esophageal epithelial cell line, Het-1A. However, we observed that activation of Notch signaling by NOTCH1icd could promote colony formation in Het-1A cells. Conclusions: Our results showed that Notch signaling promotes the growth and pathogenesis of EAC. Therefore, Notch signaling pathway could be a promising therapeutic target for treatment of human EAC. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3336. doi:1538-7445.AM2012-3336

Immunohistochemical Expression of Ki-67, PCNA, pRb, p16, p53, Bcl-2 and Bax in Esophageal Adenocarcinoma and Barrett’s Associated Dysplasia

Background: Esophageal adenocarcinoma (EAC) has an extremely poor prognosis. There is a need to characterize the molecular alterations in the carcinogenesis of EAC in order to improve the diagnosis and treatment. Materials and Methods: We used 7 markers to explore the changes in the cell cycle, proliferation and apoptosis in patients with EAC and Barrett’s esophagus (BE)-associated dysplasia. The protein expression of Ki-67, PCNA, pRb, p16, p53, Bcl-2 and Bax was evaluated by immunohistochemistry in archival tissue samples, collected from 15 patients with EAC and 5 patients with BE-associated dysplasia. We analyzed also lymph-node, omentum and liver metastases from the primary esophageal tumors. Results: Ki-67, PCNA, pRb, p16, p53, Bcl-2 and Bax expression was observed in 100%, 87%, 60%, 40%, 100%, 7% and 93% of tumor samples, and in 100%, 80%, 0%, 80%, 80%, 20% and 100% of dysplasia samples, respectively. Significant difference in the expression of the markers between EAC and BE-associated dysplasia was detected for pRb (p = 0.006). Ki-67 expression was associated with clinicopathological parameter T (p = 0.012; V = 0.585). Ninefold higher risk to develop EAC was established for the patient with strong p53 expression, than the lacking p53 patient. Patients with strong p53 expression survived 6.8 months longer than the patients with weak p53 expression and 8.6 months longer than the patients with moderate p53 expression. No correlation was found between the expression of the other markers and prognosis. Conclusion: The results suggest that Ki-67, PCNA, pRb, p16, p53 and Bax participate in the pathogenesis of EAC, whereas Bcl-2 does not play essential role in EAC and BE-associated dysplasia. The balance between cell proliferation and apoptosis is lost in EAC and BE-associated dysplasia. Abnormal p53 protein expression has predictive and prognostic value in EAC. Larger prospective studies are needed to confirm these findings.

Abstract 1092: Insulin-like growth factors modulate chemosensitivity to cisplatin and 5-fluorouracil in human esophageal cell lines

Abstract Resistance to chemotherapy remains a major obstacle to survival of patients with esophageal adenocarcinoma (EADC). The aim of this study was to evaluate whether insulin-like growth factors (IGFs), recently implicated in the molecular pathogenesis of EADC, modulate chemosensitivity to Cisplatin (CDDP) and 5-Fluoruracil (5-Fu), two agents widely used in current clinical practice. Expression of IGF1, its receptor (IGF1R), and IGF2 (mRNA and protein) were studied using quantitative (real-time) PCR and Western blot in human esophageal cell lines: Het1A (derived from immortalized normal esophageal epithelium), OE33 and JHEsoAd1 (each derived from a primary EADC). For each cell line, the effect of various concentrations of IGFs, CDDP and 5-Fu, alone and in combination, on cell proliferation and clonogenicity were evaluated by standard MTT and colony formation assays, respectively. Changes in expression of 84 critical genes downstream from IGF1R were studied by PCR-array. Relative to Het1A, IGF1 and IGF2 mRNA were significantly (P&amp;lt;0.05) underexpressed by OE33; by contrast, JHEsoAd1 underexpressed IGF1 but overexpressed IGF2. Administration of either IGF1 (250ng/ml) or IGF2 (500ng/ml) to cell cultures resulted in increased cellular proliferation of JHEsoAD1 cells (after IGF1: 1.24+/-0.05 vs. 1.00+/-0.00 untreated, P&amp;lt;0.01; after IGF2: 1.15+/-0.06 vs. 1.00+/-0.06 untreated, P&amp;lt;0.05). As expected, cell proliferation and clonogenicity of all cell lines were inhibited by CDDP and/or 5-FU (at all dosages ranging from 1-4ug/ml). However, these cytotoxic effects were overcome by the administration of either IGF1 or IGF2 with the exception of: 1) JHEsoAd1 cells treated with CDDP, where IGF2 administration further reduced cellular proliferation (0.35+/-0.06 vs. 0.53+/-0.03 for cells treated with CDDP alone; P&amp;lt;0.05), and 2) JHEsoAd1 cells treated with 5-Fu, where IGF1 administration significantly reduced clonogenicity (0.07+/-0.07 vs. 0.49+/-0.06 for cells treated with 5-Fu alone; P&amp;lt;0.05). PCR-array analysis revealed up-regulation (Het1A and JHEsoAd1) and down-regulation (OE33 and JHEsoAd1) of selected PI3K/AKT pathway genes following IGF1 and IGF2 therapy. These pre-clinical studies confirm a central role for the IGF axis in esophageal tumor biology, with potential for IGFs to enhance the cytotoxic efficacy of standard chemotherapeutic agents in esophageal cell lines. The identification of novel molecular regulatory pathways downstream from IGF1R modulated by IGF therapy may well inform future cytotoxic and targeting strategies. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1092. doi:10.1158/1538-7445.AM2011-1092

Progressive silencing of p14ARF in oesophageal adenocarcinoma

The frequency of oesophageal adenocarcinoma is increasing in Western countries for unknown reasons, and correlates with a corresponding increase in the pre-malignant condition, Barrett's Oesophagus, which raises the risk of adenocarcinoma by some 40- to 125-fold. We have examined how disease progression correlates with changes in expression of the p14ARF (ARF) tumour suppressor, a key regulator of the p53 tumour suppressor pathway that is silenced in some 30% of cancers overall, but for which a role in oesophageal cancer is unclear. We have used quantitative PCR, RT-PCR, methylation-specific PCR and chromatin-immunoprecipitation to examine the regulation and function of ARF in oesophageal adenocarcinoma tissue specimens and cell lines. We find highly significant reductions (P< 0.001) in ARF expression during disease progression from normal oesophageal epithelium to Barrett's Oesophagus to adenocarcinoma, with 57/76 (75%) adenocarcinomas displaying undetectable levels of ARF expression. Retention of ARF expression in adenocarcinoma is a highly significant indicator of increased survival (P< 0.001) and outperforms all clinical variables in a multivariate model. CpG methylation as well as histone H3 methylation of lysines 9 and 27 contribute independently to ARF gene silencing in adenocarcinoma cell lines and can be reversed by 5-aza-2′-deoxycytidine. The results suggest that silencing of ARF is involved in the pathogenesis of oesophageal adenocarcinoma and show that either DNA or histone methylation can provide the primary mechanism for ARF gene silencing. Silencing of ARF could provide a useful marker for increased risk of progression and poor prognosis.

XRCC1 and XPD polymorphisms and esophageal adenocarcinoma risk

DNA damage is important in the pathogenesis of esophageal adenocarcinoma (EA). Polymorphic variants in DNA repair genes may be modifiers of the risk of EA through their role in altering human host response to gastroesophageal acid reflux, a well-described risk factor for EA. We studied the role of genetic polymorphisms of two key DNA repair genes, xeroderma pigmentosum group D (XPD) (Asp312Asn and Lys751Gln) in the nucleotide excision repair (NER) pathway and X-ray repair cross-complementing gene 1 (XRCC1) (Arg399Gln) in the base excision repair (BER) pathway, in the development of EA in 183 cases and 336 frequency-matched controls for age, gender and race. Genomic DNA was extracted from blood samples. Odds ratios (ORs) and 95% confidence intervals (CIs) were obtained from logistic regression models, adjusted for body mass index at 18 years of age, smoking and alcohol exposure. The variant genotypes of XPD Lys751Gln polymorphism were associated with a higher risk of EA; the adjusted OR comparing Gln/Gln + Lys/Gln with Lys/Lys was 1.49 (95% CI: 1.02-2.14). Although no significant relationships were found for the XRCC1 Arg399Gln polymorphism alone, this polymorphism did modify the relationship between XPD Lys751Gln and EA risk; when both polymorphisms were evaluated together, adding the number of variant alleles of the two polymorphisms resulted in a significant trend (trend test, P = 0.008); compared with individuals with no variant alleles (n = 88), the adjusted ORs of developing EA are 1.49 (95% CI: 0.88-2.59), 1.69 (95% CI: 0.98-2.96) and 2.58 (95% CI: 1.31-5.06) for one (n = 195), two (n = 166) and three or four variant alleles (n = 70), respectively. No relationships were found for the XPD Asp312Asn polymorphism. We conclude that combined NER and BER pathways are important to the development of EA.