Increased Expression and Secretion of Interleukin-6 in Patients with Barrett’s Esophagus

A double-blind randomized clinical trial of inflammatory cytokine and pepsin levels in the saliva of patients with voice prostheses

BACKGROUND

Tracheoesophageal speech is one of the most effective method used for voice rehabilitation after laryngectomy. The main limitation is the need for periodic voice prothesis (VP) replacements. The process of developing VP usage complications is still unexplored. The aim of this study was to assess the level of cytokines (IL-1β, IL-6, IL-8, IL-10, TNFα) and pepsin in saliva as potential factors reducing VP longevity.

METHODS

Prospective double-blind randomized clinical trial was conducted (NCT04268459). Patients were randomly divided into two groups depending on VP replacement regimen (regular-every 3 months, or irregular-when complications occur). Levels of IL-1β, IL-6, IL-8, IL-10, TNFα, and pepsin in saliva samples (fasting and after eating) of laryngectomized patients were measured using ELISA tests.

RESULTS

Fifty-two patients (26 in both groups) with control group (7 patients) participated in the study. The level of IL-1β, IL-6, IL-8, IL-10, TNFα, and pepsin did not differ according to regularity of VP replacements (p = 0.301-0.801). IL-6 levels were significantly higher when VP complications occurs (p = 0.012).

CONCLUSIONS

The saliva components were not significantly different depending on the frequency of VP replacements. IL-6 plays an important role in the development of VP use complications.

Multifaceted association of overweight and metabolically unhealthy with the risk of Barrett's esophagus in the UK Biobank cohort

The association of overweight/obesity and metabolically unhealthy (MU) with the risk of developing Barrett's esophagus (BE) remains uncertain. We evaluated whether MU and overweight/obesity are associated with increased BE incidence and whether they have a synergistic impact on BE development. We analyzed the body mass index (BMI) and metabolic indicators at baseline of 402,510 individuals from the UK Biobank with no history of BE. Overweight/obesity and MU were defined as BMI ≥ 25.0 kg/m2 and presence of ≥ 1 MU indicators, respectively. Accordingly, the participants were categorized into four groups: (1) metabolically healthy non-overweight/obesity (MHNO), (2) metabolically unhealthy non-overweight/obesity (MUNO), (3) metabolically healthy overweight/obesity (MHO), and (4) metabolically unhealthy overweight/obesity (MUO). During a median follow-up of 13.5 years, 6195 (1.5%) individuals were newly diagnosed with BE. Among them, 39,281 (9.8%), 92,000 (22.9%), 25,297 (6.3%), and 245,932 (61.1%) individuals were classified as MHNO, MUNO, MHO, and MUO, respectively. In Cox regression analyses, both MU and overweight/obesity were independently associated with BE incidence. Moreover, BE incidence was significantly higher in the MUNO, MHO, and MUO groups, compared to the MHNO group. MU and overweight/obesity are independent risk factors for BE and have a synergistic effect on BE development.

Gastroesophageal reflux disease increases the risk of essential hypertension: results from the Nationwide Readmission Database and Mendelian randomization analysis

BACKGROUND

The link between gastroesophageal reflux disease (GERD) and essential hypertension (EH) and its causal nature remains controversial. Our study examined the connection between GERD and the risk of hypertension and assessed further whether this correlation has a causal relationship.

METHODS

First, we utilized the National Readmission Database including 14 422 183 participants to conduct an observational study. Dividing the population into GERD and non-GERD groups, we investigated the correlation between GERD and EH using multivariate logistic regression. Next, bidirectional two-sample Mendelian randomization was adopted. The summary statistics for GERD were obtained from a published genome-wide association study including 78 707 cases and 288 734 controls. We collected summary statistics for hypertension containing 70 651 cases and 223 663 controls from the FinnGen consortium. We assessed causality primarily by the inverse-variance weighted method with validation by four other Mendelian randomization approaches as well as an array of sensitivity analyses.

RESULTS

In the unadjusted model, GERD patients had a higher risk of EH than the non-GERD group, regardless of gender (odds ratio, 1.43; 95% confidence interval: 1.42-1.43; P < .001). Further adjusting for critical confounders did not change this association. For Mendelian randomization, we found that genetically predicted GERD was causally linked to an enhanced risk of EH in inverse-variance weighted technique (odds ratio, 1.52; 95% confidence interval: 1.39-1.67; P = 3.51 × 10-18); conversely, EH did not raise the risk of GERD causally.

CONCLUSIONS

GERD is a causal risk factor for EH. Further research is required to probe the mechanism underlying this causal connection.

Signaling Pathways in the Pathogenesis of Barrett's Esophagus and Esophageal Adenocarcinoma

Barrett's esophagus (BE) is a premalignant lesion that can develop into esophageal adenocarcinoma (EAC). The development of Barrett's esophagus is caused by biliary reflux, which causes extensive mutagenesis in the stem cells of the epithelium in the distal esophagus and gastro-esophageal junction. Other possible cellular origins of BE include the stem cells of the mucosal esophageal glands and their ducts, the stem cells of the stomach, residual embryonic cells and circulating bone marrow stem cells. The classical concept of healing a caustic lesion has been replaced by the concept of a cytokine storm, which forms an inflammatory microenvironment eliciting a phenotypic shift toward intestinal metaplasia of the distal esophagus. This review describes the roles of the NOTCH, hedgehog, NF-κB and IL6/STAT3 molecular pathways in the pathogenesis of BE and EAC.

Cancer Risk in Barrett's Esophagus: A Clinical Review

Esophageal adenocarcinoma (EAC) is rapidly increasing in incidence and is associated with a poor prognosis. Barrett's esophagus (BE) is a known precursor of esophageal adenocarcinoma. This review aims to explore Barrett's esophagus, esophageal adenocarcinoma, and the progression from the former to the latter. An overview of the definition, diagnosis, epidemiology, and risk factors for both entities are presented, with special attention being given to the areas of debate in the literature. The progression from Barrett's esophagus to esophageal adenocarcinoma is reviewed and the relevant molecular pathways are discussed. The definition of Barrett's esophagus remains debated and without international consensus. This, alongside other factors, has made establishing the true prevalence of Barrett's esophagus challenging. The degree of dysplasia can be a histological challenge, but is necessary to guide clinical management. The progression of BE to EAC is likely driven by inflammatory pathways, pepsin exposure, upregulation of growth factor pathways, and mitochondrial changes. Surveillance is maintained through serial endoscopic evaluation, with shorter intervals recommended for high-risk features.

Deoxycholic acid induces proinflammatory cytokine production by model oesophageal cells via lipid rafts

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.

Advances of Tumorigenesis, Diagnosis at Early Stage, and Cellular Immunotherapy in Gastrointestinal Malignancies

Globally, in 2018, 4.8 million new patients have a diagnosis of gastrointestinal (GI) cancers, while 3.4 million people died of such disorders. GI malignancies are tightly relevant to 26% of the world-wide cancer incidence and occupies 35% of all cancer-associated deaths. In this article, we principally investigated molecular and cellular mechanisms of tumorigenesis in five major GI cancers occurring at esophagus, stomach, liver, pancreas, and colorectal region that illustrate high morbidity in Eastern and Western countries. Moreover, through this investigation, we not only emphasize importance of the tumor microenvironment in development and treatment of malignant tumors but also identify significance of M2PK, miRNAs, ctDNAs, circRNAs, and CTCs in early detection of GI cancers, as well as systematically evaluate contribution of personalized precision medicine including cellular immunotherapy, new antigen and vaccine therapy, and oncolytic virotherapy in treatment of GI cancers.

Advances in Drug Resistance of Esophageal Cancer: From the Perspective of Tumor Microenvironment

Drug resistance represents the major obstacle to get the maximum therapeutic benefit for patients with esophageal cancer since numerous patients are inherently or adaptively resistant to therapeutic agents. Notably, increasing evidence has demonstrated that drug resistance is closely related to the crosstalk between tumor cells and the tumor microenvironment (TME). TME is a dynamic and ever-changing complex biological network whose diverse cellular and non-cellular components influence hallmarks and fates of tumor cells from the outside, and this is responsible for the development of resistance to conventional therapeutic agents to some extent. Indeed, the formation of drug resistance in esophageal cancer should be considered as a multifactorial process involving not only cancer cells themselves but cancer stem cells, tumor-associated stromal cells, hypoxia, soluble factors, extracellular vesicles, etc. Accordingly, combination therapy targeting tumor cells and tumor-favorable microenvironment represents a promising strategy to address drug resistance and get better therapeutic responses for patients with esophageal cancer. In this review, we mainly focus our discussion on molecular mechanisms that underlie the role of TME in drug resistance in esophageal cancer. We also discuss the opportunities and challenges for therapeutically targeting tumor-favorable microenvironment, such as membrane proteins, pivotal signaling pathways, and cytokines, to attenuate drug resistance in esophageal cancer.

Differential MicroRNA Signatures in the Pathogenesis of Barrett's Esophagus

OBJECTIVES:

Barrett's esophagus (BE) is the precursor lesion and a major risk factor for esophageal adenocarcinoma (EAC). Although patients with BE undergo routine endoscopic surveillance, current screening methodologies have proven ineffective at identifying individuals at risk of EAC. Since microRNAs (miRNAs) have potential diagnostic and prognostic value as disease biomarkers, we sought to identify an miRNA signature of BE and EAC.

METHODS:

High-throughput sequencing of miRNAs was performed on serum and tissue biopsies from 31 patients identified either as normal, gastroesophageal reflux disease (GERD), BE, BE with low-grade dysplasia (LGD), or EAC. Logistic regression modeling of miRNA profiles with Lasso regularization was used to identify discriminating miRNA. Quantitative reverse transcription polymerase chain reaction was used to validate changes in miRNA expression using 46 formalin-fixed, paraffin-embedded specimens obtained from normal, GERD, BE, BE with LGD or HGD, and EAC subjects.

RESULTS:

A 3-class predictive model was able to classify tissue samples into normal, GERD/BE, or LGD/EAC classes with an accuracy of 80%. Sixteen miRNAs were identified that predicted 1 of the 3 classes. Our analysis confirmed previous reports indicating that miR-29c-3p and miR-193b-5p expressions are altered in BE and EAC and identified miR-4485-5p as a novel biomarker of esophageal dysplasia. Quantitative reverse transcription polymerase chain reaction validated 11 of 16 discriminating miRNAs.

DISCUSSION:

Our data provide an miRNA signature of normal, precancerous, and cancerous tissue that may stratify patients at risk of progressing to EAC. We found that serum miRNAs have a limited ability to distinguish between disease states, thus limiting their potential utility in early disease detection.

Systemic interleukin 10 levels indicate advanced stages while interleukin 17A levels correlate with reduced survival in esophageal adenocarcinomas

Introduction

Reflux promotes esophageal adenocarcinomas (EAC) creating a chronic inflammatory environment. EAC show an increasing incidence in the Western World and median survival rates are still low. The main reasons for poor prognosis despite new multimodal therapies are diagnosis of EACs at an already advanced stage and distant metastases. Hence, we wanted to investigate the presence of systemic inflammatory interleukins (IL) and their impact on patient prognosis.

Material and methods

Systemic expression levels of pro- and anti-inflammatory markers (IL-2, IL-4, IL-6, IL-10, IL-17A and IL-22) in the sera of 43 EAC patients without neoadjuvant radiochemotherapy were measured by flow cytometric analysis. A correlation to clinicopathological data was performed. Log-rank and Cox regression analysis were used to investigate the impact on patient survival. 43 sera of age and gender matched healthy volunteers were used as controls.

Results

Increased systemic IL-6 (p = 0.044) and lower IL-17A (p = 0.002) levels were found in EAC patients as opposed to controls. A correlation of IL-10 levels with an increased T stage was found (p = 0.020). Also, systemic IL-10 levels were highly elevated in patients with distant metastasis (p<0.001). However, only systemic IL-17A levels had an influence on patient survival in multivariate analysis.

Conclusion

Systemic IL-6 levels are increased, while IL-17A levels are reduced in EAC patients compared to healthy controls. In addition, circulating IL-10 might help to identify patients with advanced disease and high IL-17A might indicate a limited prognosis.

Pathogenesis and Cells of Origin of Barrett's Esophagus

In patients with Barrett's esophagus (BE), metaplastic columnar mucosa containing epithelial cells with gastric and intestinal features replaces esophageal squamous mucosa damaged by gastroesophageal reflux disease. This condition is estimated to affect 5.6% of adults in the United States, and is a major risk factor for esophageal adenocarcinoma. Despite the prevalence and importance of BE, its pathogenesis is incompletely understood and there are disagreements over the cells of origin. We review mechanisms of BE pathogenesis, including transdifferentiation and transcommitment, and discuss potential cells of origin, including basal cells of the squamous epithelium, cells of esophageal submucosal glands and their ducts, cells of the proximal stomach, and specialized populations of cells at the esophagogastric junction (residual embryonic cells and transitional basal cells). We discuss the concept of metaplasia as a wound-healing response, and how cardiac mucosa might be the precursor of the intestinal metaplasia of BE. Finally, we discuss shortcomings in current diagnostic criteria for BE that have important clinical implications.

Exposure of Barrett's and esophageal adenocarcinoma cells to bile acids activates EGFR-STAT3 signaling axis via induction of APE1

The development of Barret’s esophagus (BE) and its progression to esophageal adenocarcinoma (EAC) is highly linked to exposure to acidic bile salts due to chronic gastroesophageal reflux disease (GERD). In this study, we investigated the role of Apurinic/apyrimidinic endonuclease 1 /redox effector factor-1 (APE-1/REF-1) in STAT3 activation in response to EAC. Our results indicate that APE1 is constitutively overexpressed in EAC whereas its expression is transiently induced in response to acidic bile salts in non-neoplastic BE. Using overexpression or shRNA knockdown of APE1, we found that APE1 is required for phosphorylation, nuclear localization, and transcription activation of STAT3. By using an APE1 redox-specific mutant (C65A) and APE1 redox inhibitor (E3330), we demonstrate that APE1 activates STAT3 in a redox-dependent manner. By using pharmacologic inhibitors and genetic knockdown systems, we found that EGFR is a required link between APE1 and STAT3. EGFR phosphorylation (Y1068) was directly associated with APE1 levels and redox function. Co-immunoprecipitation and proximity ligation assays indicated that APE-1 coexists and interacts with the EGFR-STAT3 protein complex. Consistent with these findings, we demonstrated a significant induction in mRNA expression levels of STAT3 target genes (IL-6, IL-17A, BCL-xL, Survivin and c-Myc) in BE and EAC cells, following acidic bile salts treatment. ChIP assays indicated that acidic bile salts treatment enhances binding of STAT3 to the promoter of its target genes, Survivin and BCL-xL. Inhibition of APE1/REF-1 redox activity using E3330 abrogated STAT3 DNA binding and transcriptional activity. The induction of APE-1 - STAT3 axis in acidic bile salts conditions provided a survival advantage and promoted cellular proliferation. In summary, our study provides multiple pieces of evidence supporting a critical role for APE1 induction in activating the EGFR-STAT3 signaling axis in response to acidic bile salts, the main risk factors for Barrett’s carcinogenesis.

Intravesicular administration of sodium hyaluronate ameliorates the inflammation and cell proliferation of cystitis cystica et glandularis involving interleukin-6/JAK2/Stat3 signaling pathway

Cystitis cystica et glandularis (CCEG) is a chronic cystitis that causes extreme agony in affected patients. However, there are lack of effective conservative treatments. In this study, it is evident that intravesicular sodium hyaluronate (SH) therapy significantly improved the clinical symptoms of CCEG patients and ameliorated the bladder mucosal inflammation and cell proliferation characteristics of the disease. Immunohistochemical staining showed that the staining intensities of hyaluronidase (HYAL 1/2), CD44, IL-6 and phosphorylated signal transducer and activator of transcription 3 (p-Stat3) in bladder mucosal tissue were significantly increased in CCEG patients compared with control patients and that intravesicular SH treatment suppressed these protein expression. We established a CCEG rat model by treating rats with E. coli intravesicularly, and we found that HYAL 1/2 and CD44 expression levels were significantly increased in the E. coli group compared with the NC group. Activation of the IL-6/JAK2/Stat3 pathway and the expression levels of the downstream pro-apoptotic proteins Mcl-1 and Bcl-xL were also significantly increased in the E. coli group compared with the NC group. The above changes were significantly mitigated by intravesicular SH treatment. Therefore, SH may serve as an effective therapy for CCEG by inhibiting bladder mucosal inflammation and proliferation.

The tumor microenvironment in esophageal cancer

Esophageal cancer is a deadly disease, ranking sixth among all cancers in mortality. Despite incremental advances in diagnostics and therapeutics, esophageal cancer still carries a poor prognosis, and thus there remains a need to elucidate the molecular mechanisms underlying this disease. There is accumulating evidence that a comprehensive understanding of the molecular composition of esophageal cancer requires attention to not only tumor cells but also the tumor microenvironment, which contains diverse cell populations, signaling factors, and structural molecules that interact with tumor cells and support all stages of tumorigenesis. In esophageal cancer, environmental exposures can trigger chronic inflammation, which leads to constitutive activation of pro-inflammatory signaling pathways that promote survival and proliferation. Anti-tumor immunity is attenuated by cell populations such as myeloid-derived suppressor cells (MDSCs) and regulatory T cells (Tregs), as well as immune checkpoints like programmed death-1 (PD-1). Other immune cells such as tumor-associated macrophages can have other pro-tumorigenic functions, including the induction of angiogenesis and tumor cell invasion. Cancer-associated fibroblasts secrete growth factors and alter the extracellular matrix (ECM) to create a tumor niche and enhance tumor cell migration and metastasis. Further study of how these TME components relate to the different stages of tumor progression in each esophageal cancer subtype will lead to development of novel and specific TME-targeting therapeutic strategies, which offer considerable potential especially in the setting of combination therapy.

Immature myeloid progenitors promote disease progression in a mouse model of Barrett's-like metaplasia

Cdx2, an intestine specific transcription factor, is expressed in Barrett's esophagus (BE). We sought to determine if esophageal Cdx2 expression would accelerate the onset of metaplasia in the L2-IL-1β transgenic mouse model for Barrett's-like metaplasia. The K14-Cdx2::L2-IL-1β double transgenic mice had half as many metaplastic nodules as control L2-IL-1β mice. This effect was not due to a reduction in esophageal IL-1β mRNA levels nor diminished systemic inflammation. The diminished metaplasia was due to an increase in apoptosis in the K14-Cdx2::L2-IL-1β mice. Fluorescence activated cell sorting of immune cells infiltrating the metaplasia identified a population of CD11b+Gr-1+ cells that are significantly reduced in K14-Cdx2::L2-IL-1β mice. These cells have features of immature granulocytes and have immune-suppressing capacity. We demonstrate that the apoptosis in K14-Cdx2::L2-IL-1β mice is CD8+ T cell dependent, which CD11b+Gr-1+ cells are known to inhibit. Lastly, we show that key regulators of CD11b+Gr-1+ cell development, IL-17 and S100A9, are significantly diminished in the esophagus of K14-Cdx2::L2-IL-1β double transgenic mice. We conclude that metaplasia development in this mouse model for Barrett's-like metaplasia requires suppression of CD8+ cell dependent apoptosis, likely mediated by immune-suppressing CD11b+Gr-1+ immature myeloid cells.

Rebamipide Alters the Esophageal Microbiome and Reduces the Incidence of Barrett's Esophagus in a Rat Model

BACKGROUND

Barrett's esophagus (BE) is characterized by a distinct Th2-predominant cytokine profile. However, antigens that shift the immune response toward the Th2 profile are unknown.

AIM

We examined the effects of rebamipide on the esophageal microbiome and BE development in a rat model.

METHODS

BE was induced by esophagojejunostomy in 8-week-old male Wistar rats. Rats were divided into control and rebamipide-treated group receiving either a normal or a 0.225 % rebamipide-containing diet, respectively, and killed 8, 16, 24, and 32 weeks after the operation. PCR-amplified 16S rDNAs extracted from esophageal samples were examined by terminal-restriction fragment length polymorphism (T-RFLP) analysis to assess microbiome composition. The dynamics of four bacterial genera (Lactobacillus, Clostridium, Streptococcus, and Enterococcus) were analyzed by real-time PCR.

RESULTS

The incidences of BE in the control and rebamipide group at 24 and 32 weeks were 80 and 100, and 20 and 33 %, respectively. T-RFLP analysis of normal esophagus revealed that the proportion of Clostridium was 8.3 %, while that of Lactobacillales was 71.8 %. The proportions of Clostridium increased and that of Lactobacillales decreased at 8 weeks in both groups. Such changes were consistently observed in the control but not in the rebamipide group. Clostridium and Lactobacillus expression was lower and higher, respectively, in the rebamipide group than in the control group.

CONCLUSIONS

Rebamipide reduced BE development and altered the esophageal microbiome composition, which might play a role in BE development.

Chemoprevention in Barrett's Esophagus: Current Status

Chemoprevention in Barrett's esophagus is currently applied only in research settings. Identifying pathways that can be targeted by safe, pharmaceutical or natural compounds is key to expanding the scope of chemoprevention. Defining meaningful surrogate markers of cancer progression is critical to test the efficacy of chemopreventive approaches. Combinatorial chemoprevention that targets multiple components of the same pathway or parallel pathways could reduce the risk and improve the efficacy of chemoprevention. Here we discuss the role of chemoprevention as an independent or an adjuvant management option in BE-associated esophageal adenocarcinoma.

Role of Obesity in the Pathogenesis and Progression of Barrett's Esophagus

Central obesity is involved in the pathogenesis and progression of Barrett's esophagus to esophageal adenocarcinoma. Involved are likely both mechanical and nonmechanical effects. Mechanical effects of increased abdominal fat cause disruption of the gastroesophageal reflux barrier leading to increased reflux events. Nonmechanical effects may be mediated by inflammation, via classically activated macrophages, pro-inflammatory cytokines, and adipokines such as Leptin, all of which likely potentiate reflux-mediated inflammation. Insulin resistance, associated with central obesity, is also associated with both Barrett's pathogenesis and progression to adenocarcinoma. Molecular pathways activated in obesity, inflammation and insulin resistance overlap with those involved in Barrett's pathogenesis and progression.

Metabolic syndrome increases risk of Barrett esophagus in the absence of gastroesophageal reflux: an analysis of SEER-Medicare Data

GOALS

To evaluate the association between metabolic syndrome (MetS) and risk of Barrett esophagus (BE) using the Surveillance, Epidemiology, and End Results (SEER)-Medicare linked database compared with 2 control groups--Medicare population controls and endoscopy controls.

BACKGROUND

BE principally arises as an adaptation to the proinflammatory state induced by gastroesophageal reflux disease (GERD). The relationship between obesity and BE is presumed to be mediated by GERD. However, evidence suggests central adiposity also increases risk of BE independent of GERD. Central adiposity is one risk factor defining MetS, which confers a systemic proinflammatory state--a potential GERD-independent mechanism by which obesity could increase the risk of BE.

STUDY

MetS was defined as diagnosis of at least 3 of the following conditions: obesity, elevated triglycerides, high blood pressure, and elevated fasting glucose. Multivariable logistic regression was used to estimate adjusted odds ratios and 95% confidence intervals.

RESULTS

In 2198 incident BE cases, prior MetS was significantly associated with BE (odds ratio, 1.20; 95% confidence interval: 1.07, 1.36) compared with population controls. However, GERD status modified the association; among those without prior GERD, MetS increased risk of BE by 34%; however, no association was observed among those with a prior GERD diagnosis (P-value for effect modification <0.001). MetS was not associated with risk of BE compared with endoscopy controls.

CONCLUSIONS

MetS increased the risk of BE compared with population controls, an association driven by and confined to the non-GERD stratum. MetS may mediate an association between central adiposity and BE for those without GERD.

Active matrix metalloproteases are expressed early on and are high during the Barrett's esophagus malignancy sequence

OBJECTIVE

Molecular processes underlying Barrett's malignant development are poorly understood. Matrix metalloproteases (MMPs) are enzymes involved in inflammation, tissue remodeling, and malignant development. Therefore, active MMPs may have a role in early metaplasia development and Barrett's esophagus' malignant progression. We desired to gain more insight into the role of MMPs during the Barrett's esophagus pathogenesis sequence.

MATERIAL AND METHODS

In a surgical Barrett's mouse model, and in nonmalignant Barrett's and malignant esophageal cell lines, the activity of MMPs was investigated using a MMP activatable probe. MMP activity was further validated in Barrett's esophagus and esophageal adenocarcinoma patient biopsies and was further differentiated by investigating MMP9 and MMP13 expressions.

RESULTS

The mouse model showed probe activation in stromal cells early on in the esophagitis and metaplasia stages. MMP probe activation was higher in the Barrett's and cancer cell lines and biopsies as compared to normal cells and tissues. Co-immunostainings confirmed that, at the tissue level, the probe activation was mostly confined to CD45-positive stromal cells. MMP13 expression was highest in Barrett's metaplasia, whereas MMP9 was highest in the esophageal adenocarcinomas.

CONCLUSION

During the Barrett's pathogenesis process, MMP activity is increased early on in the inflamed esophagus and remains high in metaplasia and esophageal adenocarcinoma. However, there is a switch of MMP13 to MMP9 expression once neoplasia develops. In the future, detecting specific MMP subtypes could be used for distinguishing nonmalignant from neoplastic Barrett's esophagus.

Chemoprevention in Barrett's oesophagus

Increasing incidence of oesophageal adenocarcinoma along with poor survival entails novel preventive strategies. Agents that target pro-oncogenic pathways in Barrett's mucosa could halt this neoplastic transformation. In this review, we will use epidemiological associations and molecular mechanisms to identify novel chemoprevention targets in Barrett's oesophagus. We will also discuss recent chemoprevention trials.

The role of inflammation in cancer of the esophagus

Esophageal adenocarcinoma is the eighth most common malignancy worldwide. The overall prognosis is poor, with 5-year survival ranges of approximately 15-25%, and 30-50% for patients who can be treated with curative intent. There has been a marked increase in incidence of esophageal adenocarcinoma over the last 30 years, with chronic and severe reflux, diet and obesity identified as principal factors fuelling this rise in the West. Esophageal adenocarcinoma is an exemplar model of an inflammation-associated cancer. The key molecular pathways driving tumor development and influencing tumor biology are the subject of considerable research efforts, and is the principal focus of this review. In addition, the diverse range of changes occurring in the local immune response, tissue microenvironment, metabolic profile, intracellular signaling mechanisms and microRNA signatures are discussed, as well as novel targeted therapies.

Twist 1 regulates the expression of PPARγ during hormone-induced 3T3-L1 preadipocyte differentiation: a possible role in obesity and associated diseases

BACKGROUND

Twist 1 is highly expressed in adipose tissue and has been associated with obesity and related disorders. However, the molecular function of Twist 1 in adipose tissue is unclear. Twist 1 has been implicated in cell lineage determination and differentiation. Therefore, we investigated both the role of Twist 1 in adipocyte precursor mobilization and the relationship of Twist 1 with other molecular determinants of adipocyte differentiation.

METHODS

We examined Twist 1 mRNA and protein expression in subcutaneous adipose tissues from diet-induced obese C57/BL6 mice and Wistar rats and in obese patients undergoing liposuction or adipose transplant surgeries. Twist 1 expression was measured on days 0, 2, 4, 8, and 12 of 3T3-L1 differentiation in vitro. The role of Twist 1 in adipogenesis was explored using retroviral interference of Twist 1 expression. Adipokine secretion was evaluated using a RayBio® Biotin Label-based Adipokine Array.

RESULTS

Twist 1 mRNA and protein levels were reduced in diet-induced obese mice and rats and in obese humans. Twist 1 was upregulated during 3T3-L1 preadipocyte differentiation in vitro, beginning from the fourth day of differentiation induction. Retroviral interference of Twist 1 expression did not significantly impair lipid formation; however, retroviral interference induced PPARγ mRNA and protein expression on day 4 of differentiation induction. Adipokine array analyses revealed increased secretion of CXCR4 (19.55-fold), VEGFR1 (92.13-fold), L-21 R (63.55-fold), and IL-12 R beta 1 (59.66-fold) and decreased secretion of VEGFR3 (0.01-fold), TSLP R (0.071-fold), MIP-1 gamma (0.069-fold), TNF RI/TNFRSF1A (0.09-fold), and MFG-E8 (0.06-fold).

CONCLUSIONS

Twist 1 is a regulator of adipocyte gene expression although it is not likely to regulate differentiation. We identified PPARγ as a potential target of Twist 1 and found variation in the secretion of multiple adipokines, which might indicate a prospective mechanism linking Twist 1 expression with obesity or associated diseases.

Inflammation and oxidative stress markers and esophageal adenocarcinoma incidence in a Barrett's esophagus cohort

BACKGROUND

Persons with Barrett's esophagus experience increased risk of esophageal adenocarcinoma. Prediagnostic inflammation markers predict several cancers, but their role in predicting esophageal adenocarcinoma is unknown.

METHODS

We investigated whether biomarkers of inflammation [C-reactive protein (CRP), interleukin-6 (IL6), soluble tumor necrosis factor (sTNF) receptors I and II], and of oxidative stress (F2-isoprostanes) predicted progression to esophageal adenocarcinoma in a prospective cohort of 397 patients with Barrett's esophagus, 45 of whom developed esophageal adenocarcinoma. Biomarkers were measured in stored plasma samples from two time points during follow-up, the mean of which served as the primary predictor. Adjusted hazard ratios (HR) and 95% confidence intervals (CI) were estimated using Cox regression.

RESULTS

CRP level above the median was associated with an 80% increased risk of esophageal adenocarcinoma. The HR and 95% CI adjusted for age, gender, and further adjusted for waist-hip ratio and smoking were 1.98 (1.05-3.73) and 1.77 (0.93-3.37), respectively, with Ptrend for continuous CRP = 0.04. Persons with IL6 levels above the median also had almost 2-fold increased risk [HR and 95% CI adjusted for age and gender, and further adjusted for waist-hip ratio and smoking were 1.95 (1.03-3.72) and 1.79 (0.93-3.43), respectively, but no evidence of a trend was observed]. Concentrations of TNF receptors and F2-isoprostanes were not associated with esophageal adenocarcinoma risk.

CONCLUSIONS

Further research is needed to evaluate the role of inflammation and associated markers in esophageal adenocarcinoma development in persons with Barrett's esophagus.

IMPACT

This prospective study suggests that inflammation markers, particularly CRP and IL6, may help identify persons at higher risk of progression to esophageal adenocarcinoma.

Upregulation of miRNA-143, -145, -192, and -194 in esophageal epithelial cells upon acidic bile salt stimulation

Barrett's esophagus (BE) is a metaplastic condition of the distal esophagus that occurs because of chronic gastroesophageal reflux. Previous studies have identified BE-specific microRNAs (miRNAs) in comparison with normal squamous epithelium (SQ). We hypothesized that BE-specific miRNAs could be induced in esophageal SQ cells by exposure to acid and/or bile salts. We aimed to determine whether BE-specific miRNAs are upregulated in an esophageal SQ cell line (Het-1A) in an environment with acid and/or bile salts and whether this is nuclear factor-κB (NF-κB) dependent. Acid and/or bile salt incubations were performed in Het-1A cells. Experiments were performed with or without inhibiting the NF-κB pathway. Quantitative reverse transcriptase polymerase chain reaction was performed to determine expression of miRNA-143, -145, -192, -194, cyclo-oxygenase-2 (COX2), mucin 2 (MUC2), and sex determining region Y-box 9. For validation, we determined levels of these miRNAs in biopsies from patients with reflux esophagitis and normal SQ. Significantly increased expression levels of miRNA-143 (2.7-fold), -145 (2.6-fold), -192 (2.0-fold), -194 (2.2-fold), COX2, MUC2, and sex determining region Y-box 9 were found upon acidic bile salt incubation, but not upon acid or bile salt alone. NF-κB pathway inhibition significantly decreased miRNA-143, -192, -194, COX2, and MUC2 expression. Additionally, miRNA-143, -145 and -194 expression was increased in reflux esophagitis biopsies compared with normal SQ, but no changes were found in miRNA-192 expression. Our findings suggest that upregulation of BE-specific miRNAs by acidic bile may be an early event in the transition of SQ to BE and that their expression is partly regulated by the NF-κB pathway.

Anti-inflammatory effect of full-length adiponectin and proinflammatory effect of globular adiponectin in esophageal adenocarcinoma cells

Adiponectin, an adipocyte-derived hormone with anti-inflammatory and antitumor activity, inhibits esophageal adenocarcinoma (EAC) cell proliferation and induces apoptosis. Chronic inflammation is a key process involved in initiation and progression of EAC, but the roles and mechanisms of adiponectin in inflammation have not been fully understood in EAC. We aimed to analyze the effects of two types of adiponectin, full-length adiponectin (f-Ad) and globular adiponectin (g-Ad), on inflammatory factors' expression and explore the roles of ROS/NF-κB signaling pathway in adiponectin-regulated inflammation in EAC cells. It was found that f-Ad and g-Ad differently regulated both mRNA and protein levels of TNF-α, IL-8, and IL-6 in a dose-dependent manner in OE19 cells. g-Ad apparently induced TNF-α, IL-8, and IL-6 production, which was inhibited by PDTC or NAC, and increased intracellular ROS levels and NF-κB p65 activation, whereas f-Ad significantly suppressed production of inflammatory factors and NF-κB p65 activation and also decreased the intracellular ROS levels. In conclusion, the study demonstrated that g-Ad exerts a proinflammatory effect whereas f-Ad appears to induce an anti-inflammatory effect in a ROS/NF-κB-dependent manner in OE19 cells.

An array of possibilities in cancer research using cytokine antibody arrays

Protein arrays have shown potential applications in cancer research. After several decades of research, it has become evident that many cytokines are central to the development of cancer and its treatment. Cytokine antibody arrays that have been designed to simultaneously detect multiple cytokines are not only available, but show a diversity of applications in the study of many diseases in addition to cancer. This review will focus on the implementation of cytokine antibody arrays in many aspects of cancer research, such as biomarker discovery, molecular mechanisms of cancer development, preclinical studies and the effects of cancer compounds.

1,25-dihydroxyvitamin D in the pathogenesis of Barrett's esophagus and esophageal adenocarcinoma

The incidence of reflux-related esophageal disease - Barrett's esophagus and esophageal adenocarcinoma - is rising, and the prognosis remains poor. Evidence exists that 1,25-dihydroxyvitamin D may augment the course of colon, breast and prostate cancer but little knowledge exists regarding its impact on disease of the esophagus. Important immune cells involved in reflux-related esophageal disease include CD4(+) T cells, macrophages and dendritic cells, and key signaling pathways include Wnt, Hedgehog, NFκ-B and IL-6-JAK-STAT. There is an inter-relationship between these entities and 1,25-dihydroxyvitamin D, which has been described in animal models and some human tissue. Despite this, there is an incomplete understanding of how the immune cell population and signaling pathways contribute to the course and prognosis of Barrett's esophagus and esophageal adenocarcinoma. More investigation with a focus on the clinical outcomes of patients with Barrett's esophagus and esophageal adenocarcinoma and the immune cell population and cell signaling activity in the diseased esophagus is necessary to determine the immunomodulatory role of 1,25-dihydroxyvitamin D in the pathogenesis of esophageal diseases.

Adiponectin modulates DCA-induced inflammation via the ROS/NF-κ B signaling pathway in esophageal adenocarcinoma cells

BACKGROUND

Deoxycholic acid (DCA) promotes the development and progression of esophageal adenocarcinoma (EAC) by inducing inflammation. Adiponectin is reported to have anti-inflammatory and anti-tumor effects.

PURPOSE

This study investigated the effects of two types of adiponectin, full-length adiponectin (f-Ad) and globular adiponectin (g-Ad), on DCA-induced inflammation, and investigated the involvement of the reactive oxygen species (ROS)/NF-κB signaling pathway in inflammation in EAC.

METHODS

OE19 cells were treated with DCA (50-300 μM) and/or f-Ad/g-Ad (10.0 μg/ml) or N-acetylcysteine (NAC). The viability of cells exposed to DCA was measured by use of the MTT assay. mRNA and protein levels of the inflammatory factors were examined by real-time PCR and ELISA. Intra-cellular ROS levels were determined by use of flow cytometry. Protein levels of total and p-NF-κB p65 were measured by western blot.

RESULTS

DCA induced dose and time-dependent cytotoxicity. mRNA and protein expression of TNF-α, IL-8, and IL-6 in cells treated with DCA alone were up-regulated, and intra-cellular ROS and p-NF-κB p65 protein levels were also increased. g-Ad promoted inflammatory factor production, ROS levels, and p-NF-κB p65 protein expression whereas f-Ad had a suppressive effect. When combined with DCA, g-Ad enhanced the pro-inflammatory effect of DCA whereas f-Ad, similar to NAC, suppressed the effect.

CONCLUSION

DCA has a pro-inflammatory effect in EAC. f-Ad has an anti-inflammatory effect whereas g-Ad seems to have a pro-inflammatory effect in an ROS/NF-κB p65-dependent manner. This indicates that f-Ad could be a potential anti-inflammatory reagent for cancer therapy.

Barrett's esophagus: cancer and molecular biology

The following paper on the molecular biology of Barrett's esophagus (BE) includes commentaries on signaling pathways central to the development of BE including Hh, NF-κB, and IL-6/STAT3; surgical approaches for esophagectomy and classification of lesions by appropriate therapy; the debate over the merits of minimally invasive esophagectomy versus open surgery; outcomes for patients with pharyngolaryngoesophagectomy; the applications of neoadjuvant chemotherapy and chemoradiotherapy; animal models examining the surgical models of BE and esophageal adenocarcinoma; the roles of various morphogens and Cdx2 in BE; and the use of in vitro BE models for chemoprevention studies.

The esophagitis to adenocarcinoma sequence; the role of inflammation

Esophageal adenocarcinoma (EAC) is the eighth most common cancer worldwide, and approximately 15% of patients survive 5years. Reflux disease (GERD) and Barrett's esophagus (BE) are major risk factors for the development of EAC, and epidemiologic studies highlight a strong association with obesity. The immune, inflammatory and intracellular signaling changes resulting from chronic inflammation of the esophageal squamous epithelium are increasingly well characterized. In GERD and Barrett's, an essential role for T-cells in the initiation of inflammation in the esophagus has been identified, and a balance between T-cell responses and phenotype may play an important role in disease progression. Obesity is a chronic low-grade inflammatory state, fueled by adipose tissue derived- inflammatory mediators such as IL-6, TNF-α and leptin, representing a novel area for targeted research. Additionally, reactive oxygen species (ROS) and receptor tyrosine kinase (RTK) activation may drive progression from esophagitis to EAC, and downstream signaling pathways employed by these molecules may be important. This review will explain the diverse range of mechanisms potentially driving and maintaining inflammation within the esophagus and explore both existing and future therapeutic strategies targeting the process.

Stromal cells participate in the murine esophageal mucosal injury response

We identified α-smooth muscle actin (α-SMA)- and vimentin-expressing spindle-shaped esophageal mesenchymal cells in the adult and neonate murine esophageal lamina propria. We hypothesized that these esophageal mesenchymal cells express and secrete signaling and inflammatory mediators in response to injury. We established primary cultures of esophageal mesenchymal cells using mechanical and enzymatic digestion. We demonstrate that these primary cultures are nonhematopoietic, nonendothelial, stromal cells with myofibroblast-like features. These cells increase secretion of IL-6 in response to treatment with acidified media and IL-1β. They also increase bone morphogenetic protein (Bmp)-4 secretion in response to sonic hedgehog. The location of these cells and their biological functions demonstrate their potential role in regulating esophageal epithelial responses to injury and repair.

The decreased expression of Beclin-1 correlates with progression to esophageal adenocarcinoma: the role of deoxycholic acid

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.

Inflammation and cancer

There is evidence supporting the hypothesis that inflammation participates in providing conditions that lead to cancer. An unresolved inflammation due to any failure in the precise control of the immune response can continue to perturb the cellular microenvironment, thereby leading to alterations in cancer-related genes and posttranslational modification in crucial cellular proteins involved in the cell cycle, DNA repair and apoptosis. In addition, there are data indicating that inflammatory cells and immunomodulatory mediators present in the tumor microenvironment influence tumor progression and metastasis. Historically, tumor-infiltrating leukocytes have been considered to be manifestations of an intrinsic defence mechanism against developing tumors. However, increasing evidence indicates that leukocyte infiltration can promote tumor phenotypes, such as angiogenesis, growth and invasion. This may be due to inflammatory cells that probably can influence cancer promotion by secreting cytokines, growth factors, chemokines and proteases, which stimulate proliferation and invasiveness of cancer cells. Consequently, events and molecules implicated in this cross talk between the tumor microenvironment and inflammatory process may emerge as attractive targets in anticancer therapeutic interventions with significant clinical impact.

Contribution of Fibroblast and Mast Cell (Afferent) and Tumor (Efferent) IL-6 Effects within the Tumor Microenvironment

Hyperactive inflammatory responses following cancer initiation have led to cancer being described as a 'wound that never heals'. These inflammatory responses elicit signals via NFκB leading to IL-6 production, and IL-6 in turn has been shown to induce epithelial to mesenchymal transition in breast cancer cells in vitro, implicating a role for this cytokine in cancer cell invasion. We previously have shown that conditioned medium derived from cancer-associated fibroblasts induced an Epithelial to Mesenchymal transition (EMT) in PMC42-LA breast cancer cells and we have now identify IL-6 as present in this medium. We further show that IL-6 is expressed approximately 100 fold higher in a cancer-associated fibroblast line compared to normal fibroblasts. Comparison of mouse-specific (stroma) and human-specific (tumor) IL-6 mRNA expression from MCF-7, MDA MB 468 and MDA MB 231 xenografts also indicated the stroma rather than tumor as a significantly higher source of IL-6 expression. Mast cells (MCs) feature in inflammatory cancer-associated stroma, and activated MCs secrete IL-6. We observed a higher MC index (average number of mast cells per xenograft section/average tumor size) in MDA MB 468 compared to MDA MB 231 xenografts, where all MC were observed to be active (degranulating). This higher MC index correlated with greater mouse-specific IL-6 expression in the MDA MB 468 xenografts, implicating MC as an important source of stromal IL-6. Furthermore, immunohistochemistry on these xenografts for pSTAT3, which lies downstream of the IL-6 receptor indicated frequent correlations between pSTAT3 and mast cell positive cells. Analysis of publically available databases for IL-6 expression in patient tissue revealed higher IL-6 in laser capture microdissected stroma compared to adjacent tissue epithelium from patients with inflammatory breast cancer (IBC) and invasive non-inflammatory breast cancer (non-IBC) and we show that IL-6 expression was significantly higher in Basal versus Luminal molecular/phenotypic groupings of breast cancer cell lines. Finally, we discuss how afferent and efferent IL-6 pathways may participate in a positive feedback cycle to dictate tumor progression.

Role of Th-2 cytokines in the development of Barrett's esophagus in rats

BACKGROUND

Barrett's esophagus is characterized by a distinct Th-2-predominant cytokine profile, unlike the pro-inflammatory nature of reflux esophagitis. The aim of this study was to examine the role of Th-2 cytokines during the development of Barrett's esophagus, using a rat model.

METHODS

Barrett's esophagus was induced by Levrat's esophagojejunostomy technique in Brown-Norway (BN) rats. Rats were killed at 8, 15, 30, and 50 weeks after the operation. We studied the incidences of esophagitis and Barrett's esophagus, and the mRNA expression of cytokines and CDX2 by real-time reverse transcriptase-polymerase chain reaction and immunohistochemical staining. Finally, we compared the incidence of Barrett's esophagus in BN rats with that in Sprague-Dawley (SD) rats.

RESULTS

Esophagitis was found in all rats. Barrett's esophagus appeared 8 weeks after the operation, and its incidence and length increased over time. Levels of Th-2 cytokines such as interleukin (IL)-4, IL-10, and IL-13 were significantly increased in Barrett's esophagus as compared to those in non-Barrett's esophagus, while there were no differences in the levels of pro-inflammatory cytokines. The peak of elevated IL-4 mRNA was observed before that of CDX2 mRNA. IL-4 was co-localized in CD4-positive cells and CDX2-positive goblet cells. The incidence of Barrett's esophagus was more common in BN rats (8/10, 80%) than in SD rats (2/7, 28%) at 30 weeks.

CONCLUSION

Th-2 cytokines, especially IL-4, may play a crucial role in the development of Barrett's esophagus in an early phase. These results provide understanding of the pathogenesis of Barrett's esophagus from the aspect of the Th-2 immune response.

Cancer-related inflammation and Barrett's carcinogenesis: interleukin-6 and STAT3 mediate apoptotic resistance in transformed Barrett's cells

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.

miR-200 family expression is downregulated upon neoplastic progression of Barrett’s esophagus

AIM: To investigate miR-200 family expression in Barrett’s epithelium, gastric and duodenal epithelia, and esophageal adenocarcinoma.

METHODS: Real-time reverse transcriptase-polymerase chain reaction was used to measure miR-200, ZEB1 and ZEB2 expression. Ingenuity Pathway Analysis of miR-200 targets was used to predict biological outcomes.

RESULTS: Barrett’s epithelium expressed lower levels of miR-141 and miR-200c than did gastric and duodenal epithelia (P < 0.001). In silico analysis indicated roles for the miR-200 family in molecular pathways that distinguish Barrett’s epithelium from gastric and duodenal epithelia, and which control apoptosis and proliferation. All miR-200 members were downregulated in adenocarcinoma (P < 0.02), and miR-200c expression was also downregulated in non-invasive epithelium adjacent to adenocarcinoma (P < 0.02). The expression of all miR-200 members was lower in Barrett’s epithelium derived high-grade dysplastic cell lines than in a cell line derived from benign Barrett’s epithelium. We observed significant inverse correlations between miR-200 family expression and ZEB1 and ZEB2 expression in Barrett’s epithelium and esophageal adenocarcinoma (P < 0.05).

CONCLUSION: miR-200 expression might contribute to the anti-apoptotic and proliferative phenotype of Barrett’s epithelium and regulate key neoplastic processes in this epithelium.

Characterization of squamous esophageal cells resistant to bile acids at acidic pH: implication for Barrett's esophagus pathogenesis

Barrett's esophagus (BE) is a premalignant condition, where normal squamous epithelium is replaced by intestinal epithelium. BE is associated with an increased risk of developing esophageal adenocarcinoma (EAC). However, the BE cell of origin is not clear. We hypothesize that BE tissue originates from esophageal squamous cells, which can differentiate to columnar cells as a result of repeated exposure to gastric acid and bile acids, two components of refluxate implicated in BE pathology. To test this hypothesis, we repeatedly exposed squamous esophageal HET1A cells to 0.2 mM bile acid (BA) cocktail at pH 5.5 and developed an HET1AR-resistant cell line. These cells are able to survive and proliferate after repeated 2-h treatments with BA at pH 5.5. HET1AR cells are resistant to acidification and express markers of columnar differentiation, villin, CDX2, and cytokeratin 8/18. HET1AR cells have increased amounts of reactive oxygen species, concomitant with a decreased level and activity of manganese superoxide dismutase compared with parental cells. Furthermore, HET1AR cells express proteins and activate signaling pathways associated with inflammation, cell survival, and tumorigenesis that are thought to contribute to BE and EAC development. These include STAT3, NF-κB, epidermal growth factor receptor (EGFR), cyclooxygenase-2, interleukin-6, phosphorylated mammalian target of rapamycin (p-mTOR), and Mcl-1. The expression of prosurvival and inflammatory proteins and resistance to cell death could be partially modified by inhibition of STAT3 signaling. In summary, our study shows that long-term exposure of squamous cells to BA at acidic pH causes the cells to display the same characteristics and markers as BE.

Exercise and the Prevention of Oesophageal Cancer (EPOC) study protocol: a randomized controlled trial of exercise versus stretching in males with Barrett's oesophagus

BACKGROUND

Chronic gastro-oesophageal reflux disease and excessive body fat are considered principal causes of Barrett's oesophagus (a metaplastic change in the cells lining the oesophagus) and its neoplastic progression, oesophageal adenocarcinoma. Metabolic disturbances including altered levels of obesity-related cytokines, chronic inflammation and insulin resistance have also been associated with oesophageal cancer development, especially in males. Physical activity may have the potential to abrogate metabolic disturbances in males with Barrett's oesophagus and elicit beneficial reductions in body fat and gastro-oesophageal reflux symptoms. Thus, exercise may be an effective intervention in reducing oesophageal adenocarcinoma risk. However, to date this hypothesis remains untested.The 'Exercise and the Prevention of Oesophageal Cancer Study' will determine whether 24 weeks of exercise training will lead to alterations in risk factors or biomarkers for oesophageal adenocarcinoma in males with Barrett's oesophagus. Our primary outcomes are serum concentrations of leptin, adiponectin, tumour necrosis factor-alpha, C-reactive protein and interleukin-6 as well as insulin resistance. Body composition, gastro-oesophageal reflux disease symptoms, cardiovascular fitness and muscular strength will also be assessed as secondary outcomes.

METHODS/DESIGN

A randomized controlled trial of 80 overweight or obese, inactive males with Barrett's oesophagus will be conducted in Brisbane, Australia. Participants will be randomized to an intervention arm (60 minutes of moderate-intensity aerobic and resistance training, five days per week) or a control arm (45 minutes of stretching, five days per week) for 24 weeks. Primary and secondary endpoints will be measured at baseline (week 0), midpoint (week 12) and at the end of the intervention (week 24).

DISCUSSION

Due to the increasing incidence and very high mortality associated with oesophageal adenocarcinoma, interventions effective in preventing the progression of Barrett's oesophagus are urgently needed. We propose that exercise may be successful in reducing oesophageal adenocarcinoma risk. This primary prevention trial will also provide information on whether the protective association between physical activity and cancer is causal.

TRIAL REGISTRATION

ACTRN12609000401257.

A link between the interleukin-6/Stat3 anti-apoptotic pathway and microRNA-21 in preimplantation mouse embryos

Signal transducers and activators of transcription-3 (Stat3) plays a central role in interleukin-6 (IL-6)-mediated cell proliferation by inhibiting apoptosis in a variety of cell types. MicroRNA-21 (miRNA-21), a ubiquitous miRNA, acts as an anti-apoptotic factor that seems to be indirectly but strictly linked to Stat3. In order to determine whether the IL-6 induced Stat3 anti-apoptosis pathway is linked with miRNA-21, we first determined the effects of recombinant mouse IL-6 on Stat3 expression, mouse embryo viability, and the mRNA levels of apoptosis related genes and miRNA-21 during mouse embryo development in vitro. Addition of 10 or 100 ng/ml of recombinant IL-6 to the culture medium did not affect the developmental ability of 2-cell stage embryos into blastocysts. However, total cell number was significantly increased and apoptosis was reduced in blastocyst stage embryos cultured in the presence of 100 ng/ml of recombinant IL-6. Furthermore, addition of recombinant IL-6 to the culture medium significantly increased the copy numbers of anti-apoptotic miRNA-21, up-regulated Bcl2l1, and down-regulated casp3. Similarly, the injection of mature miRNA-21 into cells up-regulated Bcl2l1 and down-regulated casp3. These results suggest that the induction of the Stat3 anti-apoptotic pathway by IL-6 is linked to miRNA-21 expression, which possibly results in the regulation of cell apoptosis in early mouse embryo development.

Inflammation and cancer: how friendly is the relationship for cancer patients?

Evidence has emerged in the last two decades that at the molecular level most chronic diseases, including cancer, are caused by a dysregulated inflammatory response. The identification of transcription factors such as NF-kappaB, AP-1 and STAT3 and their gene products such as tumor necrosis factor, interleukin-1, interleukin-6, chemokines, cyclooxygenase-2, 5 lipooxygenase, matrix metalloproteases, and vascular endothelial growth factor, adhesion molecules and others have provided the molecular basis for the role of inflammation in cancer. These inflammatory pathways are activated by tobacco, stress, dietary agents, obesity, alcohol, infectious agents, irradiation, and environmental stimuli, which together account for as much as 95% of all cancers. These pathways have been implicated in transformation, survival, proliferation, invasion, angiogenesis, metastasis, chemoresistance, and radioresistance of cancer, so much so that survival and proliferation of most types of cancer stem cells themselves appear to be dependent on the activation of these inflammatory pathways. Most of this evidence, however, is from preclinical studies. Whether these pathways have any role in prevention, progression, diagnosis, prognosis, recurrence or treatment of cancer in patients, is the topic of discussion of this review. We present evidence that inhibitors of inflammatory biomarkers may have a role in both prevention and treatment of cancer.

Bile acids as endogenous etiologic agents in gastrointestinal cancer

Bile acids are implicated as etiologic agents in cancer of the gastrointestinal (GI) tract, including cancer of the esophagus, stomach, small intestine, liver, biliary tract, pancreas and colon/rectum. Deleterious effects of bile acid exposure, likely related to carcinogenesis, include: induction of reactive oxygen and reactive nitrogen species; induction of DNA damage; stimulation of mutation; induction of apoptosis in the short term, and selection for apoptosis resistance in the long term. These deleterious effects have, so far, been reported most consistently in relation to esophageal and colorectal cancer, but also to some extent in relation to cancer of other organs. In addition, evidence is reviewed for an association of increased bile acid exposure with cancer risk in human populations, in specific human genetic conditions, and in animal experiments. A model for the role of bile acids in GI carcinogenesis is presented from a Darwinian perspective that offers an explanation for how the observed effects of bile acids on cells contribute to cancer development.

Inflammation and esophageal carcinogenesis

The incidence of esophageal adenocarcinoma is increasing largely in Western populations, and patients diagnosed with this cancer continue to have a poor prognosis. The major risk factors are gastroesophageal reflux disease and Barrett's esophagus, both of which are associated with inflammation of the esophageal squamous epithelium, a condition called reflux esophagitis. The cellular mechanisms contributing to cancer development in the esophagus are poorly understood. The chronic inflammation that is present in Barrett's esophagus creates an environment suitable for DNA damage and altered expression of genes involved in cellular proliferation and inhibition of apoptosis. Key players in the inflammatory cascade include generation of free radicals, activation of kinases pathways and transcription factors, and production of cytokines and inflammatory enzymes. The current review highlights the link between reflux-induced inflammation and esophageal carcinogenesis. Understanding the molecular pathways involved in inflammation-associated esophageal tumorigenesis could enable the development of targeted therapies and offer a better therapeutic treatment in esophageal cancer.

Cdx genes, inflammation and the pathogenesis of Barrett's metaplasia

Metaplasia is the conversion of one cell or tissue type to another and can predispose patients to neoplasia. Perhaps one of the best-known examples of metaplasia is Barrett's metaplasia (BM), a pathological condition in which the distal oesophageal epithelium switches from stratified squamous to intestinal-type columnar epithelium. BM predisposes to oesophageal adenocarcinoma and is the consequence of long-term acid bile reflux. The incidence of BM and oesophageal adenocarcinoma has risen dramatically in recent years. A key event in the pathogenesis of BM is the induction of oesophageal CDX2 expression. Importantly, recent data reveal the molecular mechanisms that link inflammation in the development of Barrett's metaplasia, CDX2 and the progression to cancer. This review highlights the relationship between inflammation, metaplasia and carcinogenesis.