Molecular mechanisms in Barrett's metaplasia and its progression

Identification of a lncRNA involved functional module for esophageal cancer subtypes

Esophageal cancer (EC) is the sixth most common cause of death from cancer and has two principal histological subtypes: esophageal squamous cell carcinoma (ESCC) and esophageal adenocarcinoma (EAC). In addition, Barrett's esophagus (BE), due to its strong association with EAC, is generally considered to be a premalignant condition of EAC. lncRNAs are believed to function in initiation and progression of multiple cancers, and therefore should play prominent, but unknown roles in the determination and behavior of different EC subtypes. In this study, by using expression profile re-annotation and differential expression (DE) analysis, we identified DE-lncRNAs and DE-protein-coding genes (DE-PCGs), and then constructed a lncRNA-PCG network, using co-expressed DE-lncRNAs (550) and DE-PCGs (5236), which was also annotated for EC subtypes. After module mining of the network, we obtained twenty candidate lncRNA-PCG modules that were ranked by gene expression and subtype-specification. Within the top four modules, we identified an ESCC specific module, two EAC-BE-specific modules and a heterologous module. Novel candidate lncRNAs were identified, in addition to lncRNAs known to be functionally connected to EC, and could be responsible for the subtype disparities in the GO biological process and at pathway levels.

Persistence of dysphagia and odynophagia after mediastinal radiation and chemotherapy in patients with lung cancer or lymphoma

Esophageal symptoms are common during radiation and chemotherapy. It is unclear how often these symptoms persist after therapy. We retrospectively reviewed medical records of 320 adults treated for nonmetastatic breast cancer (84), lung cancer (109), or Hodgkin and non-Hodgkin lymphoma (127) who were disease-free at 10-14 months after therapy. Treatment included chemotherapy with or without nonmediastinal radiation therapy (150 patients), chemotherapy plus sequential mediastinal radiation therapy (MRT) (48 patients), chemotherapy plus concurrent MRT (61 patients), or non-MRT only (61 patients). Proton pump inhibitor use was documented. All treatment groups had similar prevalence of the esophageal symptom of heartburn before therapy. Rates were higher during treatment in those who received MRT with or without chemotherapy, but declined by 10-14 months after treatment. However, low baseline rates of dysphagia (4%) and odynophagia (2%) increased significantly after combined chemotherapy and MRT to 72% for dysphagia and 62% for odynophagia (P < 0.01) during treatment and stayed significantly elevated over baseline with 27% of the patients having dysphagia and 11% having odynophagia at 10-14 months after treatment. The use of proton pump inhibitors by patients who had MRT with chemotherapy was significantly increased during and after treatment (P = 0.002). Dysphagia, odynophagia and the use of proton pump inhibitors were significantly more common both during and after treatment than before treatment in patients who received both chemotherapy and mediastinal radiation. Our data highlight the important challenge for clinicians of managing patients with lung cancer and lymphoma who have persistent esophageal problems, particularly dysphagia and odynophagia, at approximately 1 year after treatment.

Cancer stem cell radioresistance and enrichment: where frontline radiation therapy may fail in lung and esophageal cancers

Many studies have highlighted the role cancer stem cells (CSC) play in the development and progression of various types of cancer including lung and esophageal cancer. More recently, it has been proposed that the presence of CSCs affects treatment efficacy and patient prognosis. In reviewing this new area of cancer biology, we will give an overview of the current literature regarding lung and esophageal CSCs and radioresistance of CSC, and discuss the potential therapeutic applications of these findings.

Myo9B is associated with an increased risk of Barrett's esophagus and esophageal adenocarcinoma

BACKGROUND

Reflux esophagitis (RE) and Barrett's esophagus (BE) are predisposing factors for development of esophageal adenocarcinoma (EAC), the solid tumor with the fastest rising incidence in the Western world. This RE-BE-EAC cascade involves multiple host factors and consequently multiple genes. Polymorphisms in the 3' region of myosin IXB (Myo9B) are associated with chronic inflammatory gastrointestinal disorders like celiac disease and ulcerative colitis, assuming that variation in Myo9B influences the intestinal permeability.

AIM

To determine esophageal expression and the genetic variation of the Myo9B gene in the RE-BE-EAC cascade.

METHODS

DNA from 886 Caucasian participants (198 non-reflux controls, 305 RE, 254 BE, 129 EAC) was collected for the determination of the Myo9B gene polymorphism (rs2305764). Esophageal Myo9B expression was determined on biopsies from normal, RE, BE and EAC epithelium.

RESULTS

Genotype G/G was more common in BE (p = 0.032) and EAC (p = 0.046), but not in RE (p = 0.126) compared with the control group. Cytoplasmic Myo9B expression was determined in RE, BE and EAC, but most prominent in epithelial cells of BE and EAC.

CONCLUSIONS

Genetic variation of Myo9B may play a role in the etiology of BE and EAC by increasing the permeability of the epithelial barrier.

NcoI TNF-β gene polymorphism and TNF expression are associated with an increased risk of developing Barrett's esophagus and esophageal adenocarcinoma

OBJECTIVE

Esophageal cancer development is a sequence that starts with reflux esophagitis (RE), followed by Barrett's esophagitis (BE), dysplasia, and finally esophageal adenocarcinoma (EAC). Tumor necrosis factor (TNF) is a potent anti-neoplastic agent, hence DNA polymorphisms that reduce TNF levels potentially enhance the development of BE and EAC. The aim of the study was to determine the impact of TNF gene variation on the RE-BE-EAC cascade.

METHODS

DNA from 887 Caucasian participants (197 controls, 305 RE, 257 BE, 128 EAC) was tested for the gene polymorphism TNF-β NcoI, and TNF production was determined by TNF-α specific immunohistochemistry on esophageal biopsies from these BE (n = 31) and EAC (n = 4) patients.

RESULTS

As compared with healthy controls, the TNF-β NcoI A/A genotype was significantly more prevalent in BE (p = 0.04) and EAC patients (p = 0.02), but not in RE patients (p = 0.1). While TNF-α protein levels were invariably high in esophageal biopsies from EAC patients, most esophageal BE samples showed low to moderate TNF levels.

CONCLUSIONS

Chronic inflammation, like in BE, markedly increase the risk of malignant transformation. In this study, the significantly higher frequency of the TNF-β NcoI A/A genotype and the local TNF expression indicate that the pro-inflammatory cytokine TNF plays a role in the development of BE and EAC.

Math1/Atoh1 contributes to intestinalization of esophageal keratinocytes by inducing the expression of Muc2 and Keratin-20

BACKGROUND

Esophageal intestinal metaplasia, also known as Barrett's esophagus, is the replacement of the normal epithelium with one that resembles the intestine morphologically. Generally, this includes intestinal mucin-secreting goblet cells. Barrett's esophagus is an important risk factor for adenocarcinoma development. In-vitro models for Barrett's esophagus have not, to date, focused on the induction of goblet cells in Barrett's epithelium.

AIMS

To explore the contribution of Math1/Atoh1 to induction of Barrett's esophagus and intestinal mucin-secreting goblet cells from normal human esophageal epithelium.

METHODS

We explored the level and pattern of Math1/Atoh1 mRNA and protein expression in human Barrett's esophagus. Then, using retroviral-mediated gene expression, we induced Math1 mRNA and protein expression in a human esophageal keratinocyte cell line. We evaluated the effects of this ectopic Math1 expression on cell proliferation and gene expression patterns in cells cultured under two-dimensional and three-dimensional tissue-engineering conditions.

RESULTS

Math1/Atoh1 mRNA and protein are detected in human Barrett's esophagus specimens, but the mRNA levels vary substantially. In the keratinocyte expression studies, we observed that Math1/Atoh1 ectopic expression significantly reduced cell proliferation and altered cell morphology. Moreover, Math1/Atoh1 expression is associated with a more intestinalized gene expression pattern that is distinct from that reported in after studies using other intestinal transcription factors. Most significantly, we observe the induction of the Barrett's esophagus markers Mucin-2 and Keratin-20 with Math1/Atoh1 expression.

CONCLUSIONS

We conclude that ectopic Math1/Atoh1 expression makes unique contributions to intestinalization of the esophageal epithelium in Barrett's esophagus.

Functional single-nucleotide polymorphism of epidermal growth factor is associated with the development of Barrett's esophagus and esophageal adenocarcinoma

Reflux esophagitis (RO) and Barrett's esophagus (BO) can cause esophageal adenocarcinoma (OAC). The esophageal mucosa in the RO-BO-OAC cascade is chronically exposed to gastro-esophageal reflux. Epidermal growth factor (EGF) has an important role in the protection and repair of mucosal damage, and non-physiologic levels are associated with gastrointestinal tumors. The aim is to determine the functional effect of EGF gene polymorphisms on RO, BO and OAC development. A cohort of 871 unrelated Dutch Caucasians consisted of 198 healthy controls, 298 RO patients, 246 BO patients and 129 OAC patients. The frequency of the EGF-production-associated 5'UTR A+61G polymorphism was determined in these four groups. EGF immunohistochemistry was performed on BO biopsies. EGF expression was significantly lower in the G/G genotype compared with the A/G (P=0.008) and A/A (P=0.002) group. The G/G genotype was significantly more prevalent in RO (odds ratios (OR)=2.6; 95% confidence intervals (95% CI): 1.3-5.2), BO (OR=3.0; 95% CI: 1.5-6.2) and OAC (OR=4.1; 95% CI: 1.8-9.7) than in controls. The G allele is associated with reduced EGF expression and increased risk for RO, BO and OAC development. This indicates that reduced mucosal protection resulting from genetically decreased EGF expression enhances esophageal tumor development.

Effect of freeze-dried berries on the development of reflux-induced esophageal adenocarcinoma

The incidence of esophageal adenocarcinoma in humans is increasing more rapidly than any other malignancy in the United States. Animal studies have demonstrated the efficacy of freeze-dried berry supplementation on carcinogen-induced esophageal squamous cell carcinoma in rats; however, no such studies have been done in esophagoduodenal anastomosis (EDA), an animal model for reflux-induced esophageal adenocarcinoma (EAC) development. Eight-week-old male Sprague-Dawley rats were randomized into 3 groups: EDA + control diet (EDA-CD; n = 10); EDA + 2.5% black raspberry diet (EDA-BRB; n = 11) and EDA + 2.5% blueberry diet (EDA-BB; n = 12). After 2 wk of feeding the respective diets, the rats underwent EDA surgery to induce gastroesophageal reflux and then continued the diet. Measurement of feed intake suggested that all EDA-operated animals had lower feed intake starting at 10 wk after surgery and this was significant close to termination at 24 wk. There were no significant differences in either reflux esophagitis (RE), intestinal metaplasia (IM) (70% in CD, 64% in BRB, and 66% in BB; P = 0.1) or EAC incidence (30% for CD, 34% for BRB, and 25% for BB; P = 0.2) with supplementation. Berry diets did not alter COX-2 levels, but BB diet significantly reduced MnSOD levels (1.23 ± 0.2) compared to control diet (2.05 ± 0.14; P < 0.05). We conclude that a dietary supplementation of freeze-dried BRB and BB at 2.5% (w/w) was not effective in the prevention of reflux-induced esophageal adenocarcinoma in this EDA animal model.

The effect of fundoplication on proliferative and anti-apoptotic activity of esophageal mucosa in gastroesophageal reflux disease: 4-year follow-up study

OBJECTIVE

The capacity of fundoplication to prevent esophageal adenocarcinoma is controversial. Development of cancer is associated with proliferation and anti-apoptosis, for which little data exist as to their response to fundoplication. Therefore, we wanted to clarify the effect of fundoplication on the magnitude of Ki-67 and B-cell lymphoma 2 (Bcl-2) during 48 months of follow up.

METHODS

Ki-67 and Bcl-2 were assessed quantitatively from biopsies of the esophagogastric junction (EGJ) and from the distal and proximal esophagus of 20 patients with gastroesophageal reflux disease (GERD) treated by fundoplication. An upper gastrointestinal endoscopy was performed preoperatively and postoperatively at 6 months for 20 patients and 48 months for 16 patients, respectively. Ki-67 and Bcl-2 were compared to those of 7 controls.

RESULTS

Compared to the preoperative level, Ki-67 was elevated in the distal (P = 0.012) and proximal (P = 0.007) esophagus at 48 months. Compared to control values, Ki-67 was lower at 6 months in the EGJ (P = 0.037) and the proximal esophagus (P = 0.003) and higher at 48 months in the distal esophagus (P = 0.002). Compared to control values, Bcl-2 was lower at 6 months in the EGJ (P = 0.038). Correlations between Ki-67 and Bcl-2 were positive in the EGJ (P > 0.001) and in the distal (P = 0.001) and proximal esophagus (P = 0.013).

CONCLUSION

Proliferative activity after fundoplication increased during long-term follow up in the distal esophagus despite a normal fundic wrap and objective healing of GERD.

Proliferative and anti-apoptotic activity of esophageal mucosa in gastroesophageal reflux disease is not affected by fundoplication: a 4-year follow-up study

BACKGROUND

The role of fundoplication in the prevention of esophageal adenocarcinoma is controversial. Development of cancer is associated with proliferation and anti-apoptosis, for which little data exist regarding their response to fundoplication.

METHODS

Ki-67 and Bcl-2 expression was assessed in the esophagogastric junction (EGJ) and the distal and proximal esophagus of 20 patients with gastroesophageal reflux disease (GERD) treated by fundoplication and in 7 controls. Endoscopy was performed preoperatively and 6 (20 patients) and 48 months (16 patients) postoperatively.

RESULTS

There were positive correlations between Ki-67 and Bcl-2 levels in the EGJ (p > 0.001) and in the distal (p = 0.001) and proximal esophagus (p = 0.013). Compared to the preoperative level, Ki-67 expression was elevated in the distal (p = 0.012) and proximal (p = 0.007) esophagus at 48 months. In addition, compared to control values, Ki-67 expression was lower at the 6-month follow-up in the EGJ (p = 0.037) and the proximal esophagus (p = 0.003), and higher at the 48-month follow-up in the distal esophagus (p = 0.002). Compared to control values, Bcl-2 was lower at 6 months in the EGJ (p = 0.038).

CONCLUSIONS

Proliferative activity after fundoplication increased in the long term in the distal esophagus despite a normal fundic wrap and healing of GERD.

Inflammatory and microRNA gene expression as prognostic classifier of Barrett's-associated esophageal adenocarcinoma

PURPOSE

Esophageal cancer is one of the most aggressive and deadly forms of cancer; highlighting the need to identify biomarkers for early detection and prognostic classification. Our recent studies have identified inflammatory gene and microRNA signatures derived from tumor and nontumor tissues as prognostic biomarkers of hepatocellular, lung, and colorectal adenocarcinoma. Here, we examine the relationship between expression of these inflammatory genes and micro RNA (miRNA) expression in esophageal adenocarcinoma and patient survival.

EXPERIMENTAL DESIGN

We measured the expression of 23 inflammation-associated genes in tumors and adjacent normal tissues from 93 patients (58 Barrett's and 35 Sporadic adenocarcinomas) by quantitative reverse transcription-polymerase chain reaction. These data were used to build an inflammatory risk model, based on multivariate Cox regression, to predict survival in a training cohort (n = 47). We then determined whether this model could predict survival in a cohort of 46 patients. Expression data for miRNA-375 were available for these patients and was combined with inflammatory gene expression.

RESULTS

IFN-γ, IL-1α, IL-8, IL-21, IL-23, and proteoglycan expression in tumor and nontumor samples were each associated with poor prognosis based on Cox regression [(Z-score)>1.5] and therefore were used to generate an inflammatory risk score (IRS). Patients with a high IRS had poor prognosis compared with those with a low IRS in the training (P = 0.002) and test (P = 0.012) cohorts. This association was stronger in the group with Barrett's history. When combining with miRNA-375, the combined IRS/miR signature was an improved prognostic classifier than either one alone.

CONCLUSION

Transcriptional profiling of inflammation-associated genes and miRNA expression in resected esophageal Barrett's-associated adenocarcinoma tissues may have clinical utility as predictors of prognosis.

Cdx genes, inflammation, and the pathogenesis of intestinal metaplasia

Intestinal metaplasia (IM) is a biologically interesting and clinically relevant condition in which one differentiated type of epithelium is replaced by another that is morphologically similar to normal intestinal epithelium. Two classic examples of this are gastric IM and Barrett's esophagus (BE). In both, a chronic inflammatory microenvironment, provoked either by Helicobacter pylori infection of the stomach or acid and bile reflux into the esophagus, precedes the metaplasia. The Caudal-related homeodomain transcription factors Cdx1 and Cdx2 are critical regulators of the normal intestinal epithelial cell phenotype. Ectopic expression of Cdx1 and Cdx2 occurs in both gastric IM as well as in BE. This expression precedes the onset of the metaplasia and implies a causal role for these factors in this process. We review the observations regarding the role of chronic inflammation and the Cdx transcription factors in the pathogenesis of gastric IM and BE.

Exposure to both radiation and chemotherapy increases the risk of Barrett's and multilayered epithelium

The relationship between radiation and/or chemotherapy and the development of Barrett's and/or multilayered epithelium has not been investigated before. We ascertained a group of patients exposed to radiation and/or chemotherapy and an unexposed group to compare the prevalence rates of Barrett's epithelium and multilayered epithelium at the time of endoscopy in these two groups. Barrett's epithelium was found in ten of the 19 (53%) exposed patients, compared to eight of 38 (21%) unexposed subjects (P = 0.02). Six of 19 (32%) exposed patients had multilayered epithelium, compared to four of 38 (11%) unexposed subjects (P = 0.06). Twelve of the 19 exposed patients (63%) had either Barrett's or multilayered epithelium, in contrast to ten of 38 (26%) unexposed subjects (P = 0.01). Those with exposure to both chemotherapy and radiation had a significant increase in the risk for Barrett's and/or multilayered epithelium (P = 0.003). This study suggests a relationship between exposure to a combination of radiation and chemotherapy and the development of Barrett's and/or multilayered epithelium.

Bile acid alone, or in combination with acid, induces CDX2 expression through activation of the epidermal growth factor receptor (EGFR)

OBJECTIVES

Bile acids and acid are implicated in the development of Barrett's esophagus. Evidence suggests that Barrett's esophagus intestinal metaplasia may occur via induction of caudal homeobox gene 2 (CDX2). We hypothesized that induction of CDX2 by bile acids may be due to ligand-dependent transactivation of epidermal growth factor receptor (EGFR).

METHODS

Human mucosal epithelial cells (SEG-1) were treated for 0 to 24 h with up to 300 microM deoxycholic acid (DCA) at pH 7 or 5 with or without (w/wo) antibodies against EGFR ligand-binding site (Mab528, 3-5 mug/ml). Treatment with 100 ng/ml EGF served as control. CDX2 mRNA expression was determined by real-time polymerase chain reaction. EGFR activation was analyzed by Westerns of phosphorylated EGFR tyrosines.

RESULTS

Acid (pH 5) increased the induction of CDX2 mRNA expression caused by DCA. CDX2 mRNA induction was markedly reduced by EGFR blockade with Mab528. Each treatment (pH 5, DCA or pH 5 plus DCA) activated the EGFR on all tyrosines tested but in different time courses. Phosphorylation by DCA was inhibited by Mab528. Activation of EGFR by DCA at pH 5 resulted in EGFR degradation, while that by DCA alone did not.

CONCLUSION

Thus, CDX2 induction by DCA w/wo acid occurs through ligand-dependent transactivation of the EGFR. The variations in EGFR degradation pattern with DCA or DCA at pH 5 indicate differential transactivation pathways. The molecular pathogenesis of Barrett's esophagus may occur via bile-stimulated cell signaling through the EGFR.

Sorafenib triggers antiproliferative and pro-apoptotic signals in human esophageal adenocarcinoma cells

BACKGROUND AND PURPOSE

Current therapies offer scant benefit to patients with advanced esophageal adenocarcinoma. We investigated the effects of Sorafenib, a multifunctional kinase inhibitor, on several growth regulatory pathways that control cell growth and survival in SEG-1 cells derived from Barrett's adenocarcinoma.

METHODS

SEG-1 cells were exposed to acidified medium or taurocholic acid, with and without pre-incubation with Sorafenib. Cyclin D1 and E, c-Myc, and Bcl-2 expression levels as well as STAT3 activations were determined by Western blotting. Cyclin D1 mRNA was measured by real-time PCR. Apoptosis was assessed by TUNEL assay.

RESULTS

Sorafenib significantly inhibited SEG-1 cell proliferation stimulated by acid or bile acid treatments and reduced cell survival. This drug significantly reduced the up-regulations of cyclin D1, cyclin E, c-Myc, and Bcl-2 as well as the activation of STAT3 in SEG-1 cells.

CONCLUSIONS

These results support a rational basis for future clinical studies to assess the therapeutic benefit of Sorafenib in esophageal adenocarcinoma.