Increasing cyclooxygenase-2 (cox-2) gene expression in the progression of Barrett's esophagus to adenocarcinoma correlates with that of Bcl-2

Prioritization and functional analysis of GWAS risk loci for Barrett's esophagus and esophageal adenocarcinoma

Genome-wide association studies (GWAS) have identified ~ 20 genetic susceptibility loci for esophageal adenocarcinoma (EAC), and its precursor, Barrett's esophagus (BE). Despite such advances, functional/causal variants and gene targets at these loci remain undefined, hindering clinical translation. A key challenge is that most causal variants map to non-coding regulatory regions such as enhancers, and typically, numerous potential candidate variants at GWAS loci require testing. We developed a systematic informatics pipeline for prioritizing candidate functional variants via integrative functional potential scores consolidated from multi-omics annotations, and used this pipeline to identify two high-scoring variants for experimental interrogation: chr9q22.32/rs11789015 and chr19p13.11/rs10423674. Minimal candidate enhancer regions spanning these variants were evaluated using luciferase reporter assays in two EAC cell lines. One of the two variants tested (rs10423674) exhibited allele-specific enhancer activity. CRISPR-mediated deletion of the putative enhancer region in EAC cell lines correlated with reduced expression of two genes-CREB-regulated transcription coactivator 1 (CRTC1) and Cartilage oligomeric matrix protein (COMP); expression of five other genes remained unchanged (CRLF1, KLHL26, TMEM59L, UBA52, RFXANK). Expression quantitative trait locus (eQTL) mapping indicated that rs10423674 genotype correlated with CRTC1 and COMP expression in normal esophagus. This study represents the first experimental effort to bridge GWAS associations to biology in BE/EAC, and supports the utility of functional potential scores to guide variant prioritization. Our findings reveal a functional variant and candidate risk enhancer at chr19p13.11, and implicate CRTC1 and COMP as putative gene targets, suggesting that altered expression of these genes may underlie the BE/EAC risk association.

Laparoscopic Hernia Repair and Fundoplication for Gastroesophageal Reflux Disease

Antireflux surgery is challenging, and has become even more challenging with the introduction of alternative endoscopic and laparoscopic options for patients with gastroesophageal reflux disease (GERD). The Nissen fundoplication remains the gold standard for the durable relief of GERD symptoms and esophagitis. All antireflux procedures have a failure rate, and it is important to minimize factors that are associated with failure. The selection of patients for antireflux surgery as well as the choice of the procedure requires a thorough understanding of esophageal physiology and the pros and cons of various options.

Endoscopic Resection in the Esophagus

The article is a review of the principles behind endoscopic resection of esophageal dysplasia and early cancers. The techniques of endoscopic mucosal resection and endoscopic submucosal dissection are reviewed, and the supporting literature compared. Endoscopic resection is compared with esophagectomy for the management of these lesions and current areas of controversy with regard to T1b lesions and gastroesophageal reflux following resection are addressed.

Vimentin is a potential prognostic factor for tongue squamous cell carcinoma among five epithelial-mesenchymal transition-related proteins

We aimed to investigate the association of the expression levels of five epithelial-mesenchymal transition (EMT)-related proteins (Snail, Twist, E-cadherin, N-cadherin, and Vimentin) with tumorigenesis, pathologic parameters and prognosis in tongue squamous cell carcinoma (TSCC) patients by immunohistochemistry of tissue microarray. The expression levels of Snail, E-cadherin, N-cadherin and Vimentin were significantly different between the tumor adjacent normal and tumor tissues. In tumor tissues, lower E-cadherin and higher N-cadherin levels were associated with a higher grade of cell differentiation, advanced stage of disease, and lymph node metastasis. However, higher Vimentin expression was associated with poor cell differentiation and lymph node metastasis. Patients with low E-cadherin expression had poor disease-specific survival (DSS). Conversely, positive N-cadherin and higher Vimentin expression levels were associated with poor DSS and disease-free survival. Notably, our multivariate Cox regression model indicated that high Vimentin expression was an adverse prognostic factor for DSS in TSCC patients, even after the adjustment for cell differentiation, pathological stage, and expression levels of Snail, Twist, E-cadherin, and N-cadherin. Snail, E-cadherin, N-cadherin, and Vimentin were associated with tumorigenesis and pathological outcomes. Among the five EMT-related proteins, Vimentin was a potential prognostic factor for TSCC patients.

Role of chemoprophylaxis with either NSAIDs or statins in patients with Barrett's esophagus

The incidence of esophageal adenocarcinoma, a poor prognosis neoplasia, has risen dramatically in recent decades. Barrett's esophagus represents the best-known risk factor for esophageal adenocarcinoma development. Non-steroidal anti-inflammatory drugs through cyclooxygenase-2 inhibition and prostaglandin metabolism regulation could control cell proliferation, increase cell apoptosis and regulate the expression of growth and angiogenic factors. Statins can achieve equivalent effects through prenylation and subsequently control of cellular signaling cascades. At present, epidemiological studies are small and underpowered. Their data could not justify either medication as a chemo-preventive agent. Population based studies have shown a 43% reduction of the odds of developing an esophageal adenocarcinoma, leaving out or stating a 25% reduction in patients consuming non-aspirin nonsteroidal anti-inflammatory drugs and a 50% reduction in those patients consuming aspirin. They have also stated a 19% reduction of esophageal cancer incidence when statins have been used. Observational studies have shown that non-steroidal anti-inflammatory drugs could reduce the adenocarcinoma incidence in patients with Barrett's esophagus by 41%, while statins could reduce the risk by 43%. The cancer preventive effect has been enhanced in those patients taking a combination of non-steroidal anti-inflammatory drugs and statins (a 74% decrease). Observational data are equivocal concerning the efficacy of non-steroidal anti-inflammatory drug subclasses. Non-steroidal anti-inflammatory drugs clearly have substantial potential for toxicity, while statins are rather safe drugs. In conclusion, both non-steroidal anti-inflammatory drugs and statins are promising chemopreventive agents and deserve further exploration with interventional studies. In the meanwhile, their use is justified only in patients with cardiovascular disease.

Cyclooxygenase-2 expression in esophageal epithelium before and after photodynamic therapy for Barrett's esophagus with high-grade dysplasia or intramucosal carcinoma

Cyclooxygenase-2 expression is upregulated in Barrett's esophagus and esophageal adenocarcinoma. Photodynamic therapy using porfimer sodium can result in ablation of dysplasia and intramucosal carcinoma, eradication of Barrett's esophagus, and restitution of squamous epithelium. The aim of this study was to determine the effect of photodynamic therapy on cyclooxygenase-2 expression in esophageal epithelium. Paired pre- and post-photodynamic therapy biopsy samples from the same anatomical levels of 20 individuals who had undergone photodynamic therapy for Barrett's esophagus with high-grade dysplasia and/or intramucosal carcinoma were immunostained using a cyclooxygenase-2 monoclonal antibody. Cyclooxygenase-2 expression was graded in squamous epithelium, Barrett's esophagus, and neoplasia (if present) as follows: grade 0 (no staining), grade 1 (staining in 1-10% of cells), grade 2 (staining in 11-90% of cells), and grade 3 (staining in >90% of cells). Pre-photodynamic therapy median cyclooxygenase-2 expression was grade 2 (range 1-3) in neoplastic foci and grade 1 (range 1-3) in nondysplastic Barrett's esophagus (P=0.0009 for pairwise comparison). With the exception of a few cells staining in the basal epithelial layers, median cyclooxygenase-2 expression was graded as 0 (similar to controls) in both pre-photodynamic therapy squamous epithelium and post-photodynamic therapy neosquamous epithelium. This was significantly lower when compared to either neoplastic foci (P<0.0001) or nondysplastic Barrett's esophagus (P<0.0001) pre-photodynamic therapy. Notably, in four patients with post-photodynamic therapy recurrent neoplasia, cyclooxygenase-2 expression returned to elevated levels. Cyclooxygenase-2 expression is elevated in Barrett's esophagus with high-grade dysplasia or intramucosal carcinoma prior to photodynamic therapy. Following successful photodynamic therapy, cyclooxygenase-2 expression in neosquamous epithelium returns to a low baseline level similar to that observed in native esophageal squamous epithelium. Post-photodynamic therapy neoplastic recurrence is associated with elevated cyclooxygenase-2 expression. Prospective studies should determine whether cyclooxygenase inhibitors have a role as adjuvant therapy to prevent recurrence of Barrett's esophagus following endoscopic therapy.

Biomarkers in exploring the frontiers of diagnosis, prognosis, and therapy of Barrett's esophagus

Barrett's esophagus (BE) is the principal risk factor for esophageal adenocarcinoma. BE patients currently undergo periodic endoscopic surveillance with tissue sampling and histopathologic assessment for dysplasia. They frequently are prescribed proton pump inhibitors to pharmacologically suppress gastric acid that is the cause of BE. These standard endoscopic and pharmacologic approaches for managing BE are crude at best. Identification of novel tissue biomarkers within BE may allow for more accurate endoscopic risk stratification and provide potential targets for chemoprevention.

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.

The case for endoscopic treatment of non-dysplastic and low-grade dysplastic Barrett's esophagus

Non-dysplastic mucosa (ND-) in Barrett's esophagus (BE) shows clonal molecular aberrations, loss of cell cycle control, and other features of "neoplasia." These changes occur prior to morphologic expression of neoplasia (dysplasia). Morphologic evaluation of dysplasia is fraught with error, and, as a result, often leads to false-negative and false-positive diagnoses. Early "crypt dysplasia" is difficult to detect, and is often missed in routine biopsy specimens. Some studies show substantial progression rates of low-grade dysplasia (LGD), and crypt dysplasia, to esophageal adenocarcinoma (EAC). Dysplasia, even when fully developed, may, in certain circumstances, be difficult to differentiate from non-dysplastic (regenerating) BE. Radiofrequency ablation (RFA) is a safe and effective method for removing mucosa at risk of cancer. Given the difficulties of dysplasia assessment in mucosal biopsies, and the molecular characteristics of ND-BE, this technique should be considered for treatment of all BE patients, including those with ND or LGD. Post-ablation neo-squamous epithelium reveals no molecular abnormalities, and is biologically stable. Given that prospective randomized controlled trials of ablative therapy for ND-BE aiming at reducing EAC incidence and mortality are unlikely to be completed in the near future, endoscopic ablation is a valid management option. The success of RFA in achieving safe, uniform, reliable, and predictable elimination of BE allows surgeons to combine fundoplication with RFA. Currently, there is no type of treatment for dysplastic or non-dysplastic BE that achieves a complete response in 100% of patients, eliminates all risk of developing cancer, results in zero adverse events, is less expensive in terms of absolute costs than surveillance, is durable for 20+ years, or eliminates the need for surveillance. Regardless, RFA shows established safety, efficacy, durability, and cost-effective profiles that should be considered in the management of patients with non-dysplastic or low-grade dysplastic BE.

Both beta-actin and GAPDH are useful reference genes for normalization of quantitative RT-PCR in human FFPE tissue samples of prostate cancer

BACKGROUND

Beta-actin and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) have been frequently considered as constitutive house keeping genes for RT-PCR and used to normalize changes in specific gene expressions. However, these expressions have been shown to be affected by the sample type and experimental conditions. We investigated which housekeeping gene is useful to study gene expression of paraffin embedded human tissue samples of prostate cancer.

METHODS

Fifteen pairs of cancer and corresponding normal tissue were obtained from patients with prostate cancer. We evaluated gene expression of beta-actin, GAPDH, androgen receptor (AR), and heat-shock 70-kd protein 5 (HSPA5) using laser captured microdissection and quantitative RT-PCR. AR and HSPA5 gene expression were normalized to each of these reference genes using the 2(-DeltaDeltaCt) method of relative quantification. The quantity 2(Ct(normal)-Ct(cancer)) divided by ratio of cDNA(cancer)/cDNA (normal) was used for comparing differences between cancer and normal tissue in GAPDH and beta-actin expression.

RESULTS

Ct value of beta-actin was significantly correlated with that of GAPDH (r = 0.443, P = 0.014). AR and HSPA5 gene expression levels using beta-actin for normalization were significantly correlated with these gene expression levels using GAPDH (AR; r = 0.689, P = 0.004, HSPA5; r = 0.879, P < 0.001). Both reference genes were expressed more highly in cancer tissue than in normal tissue, with that of GAPDH being significantly different between cancer tissue and normal tissue (P = 0.029).

CONCLUSIONS

The good correlation between gene expression values obtained when using beta-actin and GAPDH as reference genes suggests that either gene is a valid denominator for gene expression studies in prostate cancer.

Adenocarcinoma developing in de novo Barrett's mucosa in the remnant esophagus after esophagectomy: clinical and molecular assessment

For many patients after subtotal esophagectomy and gastric pull-up, reflux of gastric contents to the esophageal stump is the leading clinical problem. Besides symptoms such as heartburn and regurgitation, de novo formation of columnar mucosa in the esophageal remnant is a well-known and frequent phenomenon. In this context, the remnant supra-anastomotic esophagus serves as an in vivo model for the study of Barrett's carcinogenesis. We present a retrospective case analysis of a patient who developed de novo Barrett's metaplasia followed by de novo invasive carcinoma 28 months after gastric pull-up by assessing clinical and molecular parameters.

Systematic review: the application of molecular pathogenesis to prevention and treatment of oesophageal adenocarcinoma

BACKGROUND

Oesophageal adenocarcinoma is an increasingly common cancer with a poor prognosis. It develops in a stepwise progression from Barrett's metaplasia to dysplasia, and then adenocarcinoma followed by metastasis.

AIM

To outline the key molecular changes in oesophageal adenocarcinoma and to summarize the chemopreventative and therapeutic strategies proposed.

METHODS

A literature search was performed to identify appropriate research papers in the field. Search terms included: Barrett's (o)esophagus, intestinal metaplasia, (o)esophageal adenocarcinoma, molecular changes, genetic changes, pathogenesis, chemoprevention, therapeutic strategies and treatment. The search was restricted to English language articles.

RESULTS

A large number of molecular changes have been identified in the progression from Barrett's oesophagus to oesophageal adenocarcinoma although there does not appear to be an obligate order of events. Potential chemoprevention strategies include acid suppression, anti-inflammatory agents and antioxidants. In established adenocarcinoma, targeted treatments under evaluation include receptor tyrosine kinase inhibitors of EGFR and cyclin-dependent kinase inhibitors, which may benefit a subgroup of patients.

CONCLUSIONS

Advances in molecular methodology have led to a greater understanding of the oesophageal adenocarcinoma pathways, which provides opportunities for chemoprevention and therapeutic strategies with a mechanistic basis. More work is required to assess both the safety and efficacy of these new treatments.

Systematic review: Cyclo-oxygenase-2 in human oesophageal adenocarcinogenesis

BACKGROUND

Published in vitro and animal in vivo studies have demonstrated that cyclo-oxygenase-2 plays an important role during oesophageal adenocarcinogenesis. However, the extent to which these studies are directly relevant to events in the human lower oesophagus is questionable.

AIM

To perform a systematic review of all available human studies that have evaluated levels of cyclo-oxygenase-2 expression during the progression from Barrett's metaplasia to oesophageal adenocarcinoma.

METHODS

A literature search was performed to identify all studies which qualitatively or quantitatively assessed cyclo-oxygenase-2 protein or gene expression in either Barrett's, dysplastic or adenocarcinoma tissue in humans.

RESULTS

A total of 27 studies met the inclusion criteria. There was general agreement that cyclo-oxygenase-2 was either absent or very weakly expressed in normal oesophageal squamous mucosa, but considerable disagreement regarding the presence of cyclo-oxygenase-2 in Barrett's and low-grade dysplasia. All studies agreed that high-grade dysplasia and adenocarcinoma expressed cyclo-oxygenase-2 to some extent although levels varied considerably between tissue samples.

CONCLUSIONS

There is conflicting evidence in the literature for cyclo-oxygenase-2 playing an important role in early oesophageal adenocarcinogenesis. Other non-cyclo-oxygenase-2 targets may account for the epidemiological data supporting the use of non-steroidal anti-inflammatory drugs in the chemoprevention of oesophageal adenocarcinoma.