Cyclooxygenase-2 expression in Barrett's esophagus

Translating Molecular Biology Discoveries to Develop Targeted Cancer Interception in Barrett's Esophagus

Esophageal adenocarcinoma (EAC) is a rapidly increasing lethal tumor. It commonly arises from a metaplastic segment known as Barrett's esophagus (BE), which delineates the at-risk population. Ample research has elucidated the pathogenesis of BE and its progression from metaplasia to invasive carcinoma; and multiple molecular pathways have been implicated in this process, presenting several points of cancer interception. Here, we explore the mechanisms of action of various agents, including proton pump inhibitors, non-steroidal anti-inflammatory drugs, metformin, and statins, and explain their roles in cancer interception. Data from the recent AspECT trial are discussed to determine how viable a multipronged approach to cancer chemoprevention would be. Further, novel concepts, such as the repurposing of chemotherapeutic drugs like dasatinib and the prevention of post-ablation BE recurrence using itraconazole, are discussed.

Discovery of a Redox-Activatable Chemical Probe for Detection of Cyclooxygenase-2 in Cells and Animals

Cyclooxygenase-2 (COX-2) expression is up-regulated in inflammatory tissues and many premalignant and malignant tumors. Assessment of COX-2 protein in vivo, therefore, promises to be a powerful strategy to distinguish pathologic cells from normal cells in a complex disease setting. Herein, we report the first redox-activatable COX-2 probe, fluorocoxib Q (FQ), for in vivo molecular imaging of pathogenesis. FQ inhibits COX-2 selectively in purified enzyme and cell-based assays. FQ exhibits extremely low fluorescence and displays time- and concentration-dependent fluorescence enhancement upon exposure to a redox environment. FQ enters the cells freely and binds to the COX-2 enzyme. FQ exhibits high circulation half-life and metabolic stability sufficient for target site accumulation and demonstrates COX-2-targeted uptake and retention in cancer cells and pathologic tissues. Once taken up, it undergoes redox-mediated transformation into a fluorescent compound fluorocoxib Q-H that results in high signal-to-noise contrast and differentiates pathologic tissues from non-pathologic tissues for real-time in vivo imaging.

The Role of Microbiota in the Pathogenesis of Esophageal Adenocarcinoma

Simple Summary

Esophageal adenocarcinoma has a poor 5-year survival rate and is among the highest mortality cancers. Changes in the esophageal microbiome have been associated with cancer pathogenesis; however, the molecular mechanism remains obscure. This review article critically analyzes the molecular mechanisms through which microbiota may mediate the development and progression of esophageal adenocarcinoma and its precursors-gastroesophageal reflux disease and Barrett’s esophagus. It summarizes changes in esophageal microbiome composition in normal and pathologic states and subsequently discusses the role of altered microbiota in disease progression. The potential role of esophageal microbiota in protecting against the development of esophageal adenocarcinoma is also discussed. By doing so, this article highlights specific directions for future research developing microbiome-mediated therapeutics for esophageal adenocarcinoma.

Abstract

Esophageal adenocarcinoma (EAC) is associated with poor overall five-year survival. The incidence of esophageal cancer is on the rise, especially in Western societies, and the pathophysiologic mechanisms by which EAC develops are of extreme interest. Several studies have proposed that the esophageal microbiome may play an important role in the pathophysiology of EAC, as well as its precursors—gastroesophageal reflux disease (GERD) and Barrett’s esophagus (BE). Gastrointestinal microbiomes altered by inflammatory states have been shown to mediate tumorigenesis directly and are now being considered as novel targets for both cancer treatment and prevention. Elucidating molecular mechanisms through which the esophageal microbiome potentiates the development of GERD, BE, and EAC will provide a foundation on which new therapeutic targets can be developed. This review summarizes current findings that elucidate the molecular mechanisms by which microbiota promote the pathogenesis of GERD, BE, and EAC, revealing potential directions for additional research on the microbiome-mediated pathophysiology of EAC.

Biotin-Pt (IV)-indomethacin hybrid: A targeting anticancer prodrug providing enhanced cancer cellular uptake and reversing cisplatin resistance

A Pt(IV) prodrug (2) composed of cancer-targeting biotin and nonsteroidal anti-inflammatory drug indomethacin in the axial positions of the six-coordinated octahedral geometry derived from cisplatin was developed, which could be highly accumulated in cancer cells more than normal ones and activated by endogenous reducing molecules to release cisplatin and indomethacin moieties simultaneously to inhibit tumor progression synergistically. In vitro assays revealed that 2 exhibited significantly selective inhibition to the tested cancer cell lines and sensitivity to cisplatin resistant cancer cells. Moreover, 2 presented cyclooxygenases inhibition properties to reduce tumor-associated inflammation, reduced the invasiveness of the highly aggressive PC-3 cells, and disrupted capillary-like tube formation in EA.hy926 cells. In all, this study offers a new strategy to enhance sensitivity and reduce toxicity of cisplatin.

Esophageal Adenocarcinoma: The Influence of Medications Used to Treat Comorbidities on Cancer Prognosis

Esophageal adenocarcinoma has undergone a continuous rise in incidence since the early 1970s and is the fastest rising cancer among white men in the United States. Epidemiologic studies have demonstrated that medications commonly used to treat multiple chronic conditions (for example, aspirin, non-aspirin nonsteroidal anti-inflammatory drugs, and statins) as well as powerful acid suppressants such as proton pump inhibitors are associated with a reduced risk of esophageal adenocarcinoma. The chemopreventive potential of these classes of medications appears to be especially applicable to persons with Barrett's esophagus, the only known premalignant condition for esophageal adenocarcinoma. However, it is not known whether these medications also influence cancer recurrence and cancer-specific mortality in persons diagnosed with esophageal adenocarcinoma. This is an important question because most patients with esophageal adenocarcinoma have 1 or more comorbid conditions at the time of their cancer diagnosis and are receiving medication to treat these conditions. This article summarizes the evidence on the associations between 4 commonly used classes of medications and (1) risk of developing esophageal adenocarcinoma and Barrett's esophagus and (2) risk of cancer recurrence and cancer-specific mortality in patients with esophageal adenocarcinoma.

Nonsteroidal anti-inflammatory drugs and the risk of Barrett's esophagus

BACKGROUND & AIMS

Nonsteroidal anti-inflammatory drugs (NSAIDs) have been suggested to protect against esophageal adenocarcinoma (EAC). This study examined the effect of NSAIDs on the risk of developing Barrett's esophagus (BE), the precursor lesion to EAC.

METHODS

We conducted a case-control study among eligible patients scheduled for either elective esophagogastroduodenoscopy (EGD) or recruited from primary care clinics to undergo a study EGD. We compared 323 patients with BE (296 nondysplastic and 27 dysplastic) with 2 separate control groups: 1347 patients from the elective EGD group (endoscopy controls) and 502 patients from the primary care group (primary care controls) with no endoscopic or histopathologic BE. Use of aspirin products and 23 nonaspirin NSAIDs was ascertained from detailed, self-reported questionnaires. We calculated odds ratios (ORs) and 95% confidence intervals (CIs) using multivariable logistic regression models.

RESULTS

There were no significant differences in self-reported NSAID use between all BE cases and all controls (58.2% vs 54.6%; P = .33); this was seen for aspirin products (43.0% vs 37.4%; P = .08) and nonaspirin NSAIDs (7.7% vs 8.9%; P = .46). These findings persisted in the multivariable model for any NSAIDs (adjusted OR, 0.89; 95% CI, 0.75-1.28), aspirin (adjusted OR, 1.16; 95% CI, 0.90-1.51), and nonaspirin NSAIDs (adjusted OR, 0.88; 95% CI, 0.55-1.39). Use of a combination of aspirin and nonaspirin NSAIDs was reported in 7.4% of cases and 8.3% of controls, and a nonsignificant inverse association with BE was seen (adjusted OR, 0.70; 95% CI, 0.44-1.11). There was no significant association between BE and daily NSAID use (adjusted OR, 1.03; 95% CI, 0.78-1.37). Similar findings were observed for comparisons involving nondysplastic or dysplastic BE cases, and endoscopy or primary care control groups separately or combined.

CONCLUSIONS

The use of NSAIDs was not associated with a reduced risk of BE. It is likely that the protective mechanism of NSAIDs on EAC occurs subsequent to the development of BE.

Cyclooxygenase inhibitors use is associated with reduced risk of esophageal adenocarcinoma in patients with Barrett's esophagus: a meta-analysis

Background:

Esophageal adenocarcinoma (EAC) has high mortality and is increasing in incidence. Barrett's esophagus (BE) increases the risk for EAC. Studies have reported inconsistent findings on the association between use of cyclooxygenase (COX) inhibitors and the risk of neoplastic progression in BE patients. Therefore, we performed a meta-analysis to investigate this association.

Methods:

A meta-analysis was undertaken among a total of 9 observational studies using fixed- and random-effects models, comprising 5446 participants; 605 had EAC or high-grade dysplasia (HGD).

Results:

Overall, COX inhibitors use was associated with a reduced risk of EAC/HGD among BE patients (relative risk (RR)=0.64, 95% confidence interval (CI)=0.53–0.77). Aspirin use also reduced the risk of EAC/HGD (RR=0.63, 95% CI=0.43–0.94), as well as non-aspirin COX inhibitors (RR=0.50, 95% CI=0.32–0.78). The chemopreventive effect seemed to be independent of duration response.

Conclusions:

Cyclooxygenase inhibitors use is associated with a reduced risk of developing EAC in patients with BE. Both low-dose aspirin and non-aspirin COX inhibitors are associated with a reduced risk of neoplasia. More well-designed randomised controlled trials are needed to increase our understanding of the chemopreventive effect of COX inhibitors.

Aspirin protects against Barrett's esophagus in a multivariate logistic regression analysis

BACKGROUND & AIMS

Better criteria are needed to identify patients who should be screened for Barrett's esophagus (BE) to reduce overtesting and improve the cost effectiveness. There is evidence that chemopreventive agents such as nonsteroidal anti-inflammatory drugs, particularly aspirin, reduce the risk of esophageal adenocarcinoma (EAC), but little is known about their effects on BE. We analyzed characteristics of patients with BE for factors that might be used in screening and management.

METHODS

In this case-controlled study, we identified 434 patients with BE diagnosed at the first endoscopy (incident cases) at a single institution (1997-2010). BE cases were matched with controls on the basis of indication for endoscopy, year of endoscopy, and endoscopist. Risk factors analyzed included age, sex, body mass index, medical and social history, and medications. We performed a multivariate logistic regression analysis to identify clinical risk factors for BE.

RESULTS

In a multivariate regression model, men had a greater risk for developing BE (odds ratio, 3.2; 95% confidence interval, 2.3-4.4), whereas current aspirin users had a lower risk than nonusers (odds ratio, 0.56; 95% confidence interval, 0.39-0.80). A subset analysis, limited to patients who had endoscopies for symptoms of gastroesophageal reflux disease, yielded similar findings. No interactions were found between aspirin use and smoking or use of acid-suppressive medications.

CONCLUSIONS

In a case-controlled study of 434 patients with BE, current aspirin use appeared to reduce the risk of BE; previous studies associated aspirin use with a reduced risk of EAC. Although efforts were made to minimize biases in our analysis, the possibility of residual confounding remains.

Review: Experimental models for Barrett's esophagus and esophageal adenocarcinoma

Several different cell culture systems and laboratory animal models have been used over the years to study Barrett's esophagus (BE) and esophageal adenocarcinoma (EAC). Most of the existing models have key differences with the human esophagus and complex pathogenesis of disease. None of the models offers an ideal system for the complex study of environmental exposure, genetic risk, and prevention strategies. In fact, different model systems may be required to answer different specific research questions about the pathogenesis of BE and EAC. Given the high mortality associated with EAC and the fact that current screening strategies miss most cases of EAC, advances in basic and translational science related to esophageal injury, repair, and carcinogenesis are clearly needed. This review describes several of the existing and potential model systems for BE and EAC with their benefits and disadvantages.

Inflammation and Barrett's carcinogenesis

Barrett's esophagus (BE) is one of the most common premalignant lesions in which normal squamous epithelium of the esophagus is replaced by metaplastic columnar epithelium. Esophageal adenocarcinoma (EA) develops through progression from BE to low- and high-grade dysplasia (LGD/HGD) and to adenocarcinoma. It is widely accepted that inflammation can increase cancer risk, promoting tumor progression. Therefore, inflammation is regarded as the seventh hallmark of cancer. In recent years, the inflammation-cancer connection of Barrett's carcinogenesis has been intensively studied, unraveling genetic abnormalities. Besides genetic alterations, inflammation is also epigenetically linked to loss of protein expression through transcriptional silencing via promoter methylation. Key mediators linking inflammation and Barrett's carcinogenesis include reactive oxygen species (ROS), NFκB, inflammatory cytokines, prostaglandins, and specific microRNAs (miRNAs). Therefore, the decipherment of molecular pathways that contain these and novel inflammatory key mediators is of major importance for diagnosis, therapy, and prognosis. The detailed elucidation of the signaling molecules involved in Barrett's carcinogenesis will be important for the development of pharmaceutical inhibitors. We herein give an overview of the current knowledge of the inflammation-mediated genetic and epigenetic alterations involved in Barrett's carcinogenesis. We highlight the role of oxidative stress and deregulated DNA damage checkpoints besides the NFκB pathway.

Non-surgical treatments of primary, non-melanoma eyelid malignancies: a review

The diagnosis and management of periocular cutaneous malignancies are essential components of an ophthalmologist's practice. Skin cancers comprise nearly one-third of newly diagnosed malignancies. Furthermore, the incidence of skin cancer appears to be increasing. Multiple treatment modalities exist for periocular cutaneous malignancy. Surgical extirpation, often with the combined expertise of a Mohs micrographic surgeon, is typically the first line therapy and is often curative in the periocular region, depending on a variety of factors, including tumour histology, specific location, depth of invasion and surgical technique. However, there are instances where a less invasive, non-surgical treatment option is warranted, including patients who are poor surgical risks or those with diffuse disease. The purpose of this article is to review the literature and describe the non-surgical treatment options, indications and efficacies for non-melanoma primary eyelid malignancies.

Preferential up-regulation of heparanase and cyclooxygenase-2 in carcinogenesis of Barrett's oesophagus and intestinal-type gastric carcinoma

AIMS

Metaplastic changes secondary to chronic inflammation at the gastro-oesophageal junction and at the pyloric antrum are recognized as the premalignant conditions of Barrett's oesophageal adenocarcinoma and intestinal-type gastric carcinoma (GC), respectively. Heparanase (HPSE) and cyclooxygenase (COX)-2 have been proved to play critical roles in inflammation as well as in cancer. The aim was to examine the meaning of their expression in inflammation-related carcinogenesis.

METHODS AND RESULTS

First, expression of HPSE and COX-2 in 78 clinical tissues of Barrett's oesophagus was examined by immunohistochemistry and in situ hybridization. Their expression was increased during the metaplasia-dysplasia sequence with increased neovascularization. Successively, their expression in Barrett's dysplasia was compared with that of GC (22 cases of diffuse-type and 10 of intestinal-type). Interestingly, the expression pattern in Barrett's dysplasia was similar to that in intestinal-type GC, which mainly arises from chronic inflammation. Furthermore, cultured cell lines isolated from differentiated GC tissues, which are often found to be of intestinal-type, revealed up-regulated mRNA expression of HPSE and COX-2.

CONCLUSIONS

HPSE and COX-2 are preferentially up-regulated in Barrett's oesophagus and intestinal-type GC. These molecules may play an important role during the development of inflammation-related adenocarcinoma of the upper gastrointestinal tract.

Selective visualization of cyclooxygenase-2 in inflammation and cancer by targeted fluorescent imaging agents

Effective diagnosis of inflammation and cancer by molecular imaging is challenging because of interference from nonselective accumulation of the contrast agents in normal tissues. Here, we report a series of novel fluorescence imaging agents that efficiently target cyclooxygenase-2 (COX-2), which is normally absent from cells, but is found at high levels in inflammatory lesions and in many premalignant and malignant tumors. After either i.p. or i.v. injection, these reagents become highly enriched in inflamed or tumor tissue compared with normal tissue and this accumulation provides sufficient signal for in vivo fluorescence imaging. Further, we show that only the intact parent compound is found in the region of interest. COX-2-specific delivery was unambiguously confirmed using animals bearing targeted deletions of COX-2 and by blocking the COX-2 active site with high-affinity inhibitors in both in vitro and in vivo models. Because of their high specificity, contrast, and detectability, these fluorocoxibs are ideal candidates for detection of inflammatory lesions or early-stage COX-2-expressing human cancers, such as those in the esophagus, oropharynx, and colon.

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.

Cyclooxygenases, prostanoids, and tumor progression

In response to various growth factors, hormones or cytokines, arachidonic acid can be mobilized from phospholipids pools and converted to bioactive eicosanoids through cyclooxygenase (COX), lipoxygenase (LOX) or P-450 epoxygenase pathway. The COX pathway generates five major prostanoids (prostaglandin D(2), prostaglandin E(2), prostaglandin F(2)alpha, prostaglandin I(2) and thromboxane A(2)) that play important roles in diverse biological processes. Studies suggest that different prostanoids and their own synthase can play distinct roles in tumor progression and cancer metastasis. COX-2 and PGE(2) synthase have been most well documented in the regulation of various aspects of tumor progression and metastasis. PGE(2), for example, can stimulate angiogenesis or other signaling pathways by binding to its receptors termed EPs. Therefore, targeting downstream prostanoids may provide a new avenue to impede tumor progression. In this review, aberrant expression and functions of several prostanoid synthetic enzymes in cancer will be discussed. The possible regulation of tumor progression by prostaglandins and their receptors will also be discussed.

Nonsteroidal anti-inflammatory drugs and risk of esophageal and gastric adenocarcinomas in Los Angeles County

BACKGROUND

Nonsteroidal anti-inflammatory drug (NSAID) use has been associated with a reduced risk of colon cancer; further epidemiologic data appear consistent for stomach and esophageal adenocarcinomas. Yet, data on potential confounding effects by upper gastrointestinal tract (UGI) disorders on adenocarcinomas of the UGI are limited.

METHODS

This study recruited newly diagnosed patients with esophageal adenocarcinoma (n = 220), gastric cardia adenocarcinoma (n = 277), or distal gastric adenocarcinoma (n = 441) as well as 1,356 control subjects in Los Angeles County. Unconditional multivariable logistic regression analyses were done to evaluate the association between regular NSAID use, at least two pills per week for 1 month, and these cancers.

RESULTS

Duration of regular use of aspirin and non-aspirin NSAIDs was associated with reduced relative odds of distal gastric adenocarcinoma [>5 years use versus no regular use: odds ratio (OR), 0.61; 95% confidence interval, 0.40-0.92; P(trend) = 0.009] and esophageal adenocarcinoma (OR, 0.60; 95% confidence interval, 0.38-0.95; P(trend) = 0.04) in multivariable models that included history of UGI disorders and other potential confounding factors. Daily regular use was also associated with statistically significant reduced ORs of these two tumor types. No significant heterogeneity in risk estimates was noted after stratification by history of UGI disorders for any of the sites studied. However, irregular users of NSAIDs also had reduced risk of these cancers when compared with nonusers.

CONCLUSIONS

Results from this study support an inverse association between regular NSAID use and risk of esophageal and distal gastric adenocarcinomas in individuals with and without a history of UGI disorders with long duration and daily use, providing the greatest risk reduction. Reduced risk in irregular users suggests that factors other than an effect on cyclooxygenase may also be important.

COX-2 CA-haplotype is a risk factor for the development of esophageal adenocarcinoma

BACKGROUND

Neoplastic progression of BE towards EAC is associated with increased expression of COX-2. Increased COX-2 expression and enzyme activity is linked to the COX-2 CA haplotype, which consists of two gene polymorphisms in the COX-2 promoter.

AIM

To study the impact of COX-2 haplotypes on the risk of developing EAC in patients with different forms of gastroesophageal reflux disease including BE.

METHODS

DNA was obtained from a total of 635 Dutch white patients comprised of 140 patients with EAC, 255 with BE, and 240 with reflux esophagitis. COX-2 haplotypes were based on the gene polymorphisms at -765C/G and -1195A/G, as determined by PCR-RFLP.

RESULTS

The tested population contained 170 (14%) CA- (-765C and -1195A) haplotypes, 829 (65%) GA and 271 (21%) GG-haplotypes, and no GC-haplotypes. The haplotype distribution in patients with reflux esophagitis and BE was similar (CA 12%, GA 68%, GG 21%), but differed significantly from that in patients with EAC (CA 21%, GA 58%, GG 20%). Particularly, the CA-haplotype was more common (P < 0.001) in EAC patients. CA-carriership was associated with EAC (OR 2.8, 95% CI 1.3-6.2, P= 0.008), with homozygosity for the CA-allele being statistically most significantly associated (OR 6.1, 95% CI 1.6-24.2, P= 0.01).

CONCLUSION

The COX-2 CA-haplotype is more frequently observed in patients with EAC than in patients with BE and reflux esophagitis. These data suggest a direct link between COX-2 activity and neoplastic progression in patients with BE and reflux esophagitis.

Predictors for squamous re-epithelialization of Barrett's esophagus after endoscopic biopsy

BACKGROUND AND AIM

Acid suppressive therapy has been reported to regress Barrett's esophagus. However, it is still controversial as to whether all Barrett's esophagus patients respond to this therapy. The factors that might facilitate newly developed squamous re-epithelialization after biopsy excision of Barrett's mucosa were evaluated to identity individuals who may favorably respond to the regression therapy.

METHODS

Two hundred and forty-seven biopsy sites from 185 patients with Barrett's esophagus were examined by endoscopy to investigate possible squamous re-epithelialization of Barrett's mucosa after endoscopic biopsy. Before endoscopic examination, all participants were requested to answer questionnaires concerning sociodemographic characteristics, lifestyle habits and drugs usage. The mucin phenotype, Cdx2 expression, cyclooxygenase-2 expression, cellular proliferation and apoptosis of Barrett's mucosa were immunohistochemically investigated in the biopsy samples taken from Barrett's esophagus. The influence of these factors on the newly developed squamous re-epithelialization of Barrett's mucosa after endoscopic biopsy excision was evaluated.

RESULTS

By multivariate analysis, the independent factors that favored squamous re-epithelialization were the gastric mucin predominant phenotype of Barrett's mucosa and the absence of Cdx2 protein expression. In Barrett's mucosa with the gastric predominant mucin phenotype, proton pump inhibitor administration, the absence of reflux esophagitis and a low proliferating cell nuclear antigen index were found to be independent predictors for squamous re-epithelialization.

CONCLUSIONS

The absence of the intestinal predominant mucin phenotype was a positive predictor for newly developed squamous re-epithelialization at the site of biopsy of Barrett's mucosa. Only Barrett's esophagus with the gastric predominant mucin phenotype may predict a favorable response to acid suppressive therapy.

COX-2, CDX2, and CDC2 immunohistochemical assessment for dysplasia-carcinoma progression in Barrett's esophagus

BACKGROUND

Immunohistochemical changes associated with development of cancer in Barrett's esophagus offer potential areas of intervention to prevent and manage esophageal cancer.

AIMS

To assess the role of cyclooxygenase 2, caudal-type homeobox transcription factor 2 and cell division cycle 2/cyclin-dependent kinase 1 in the Barrett's metaplasia-dysplasia-adenocarcinoma sequence.

PATIENTS AND METHODS

Specimens from 46 patients with Barrett's esophagus (39% without dysplasia, 33% with dysplasia and 28% with adenocarcinoma) were stained for cyclooxygenase 2, caudal-type homeobox transcription factor 2 and cell division cycle 2.

RESULTS

Cyclooxygenase 2: No expression differences between groups were found, except for adenocarcinomas (p=0.04). Caudal-type homeobox transcription factor 2: Nuclear positivity decreased from Barrett's esophagus without dysplasia (71.6%), to Barrett's esophagus with low grade dysplasia (35.3%), to Barrett's esophagus with high grade dysplasia (17.14%); in adenocarcinoma these percentages were intermediate between high and low grade dysplasia (30.5%). Cell division cycle 2: Expression on deeper glandular structures was 40% in Barrett's esophagus without dysplasia, 55.47% in Barrett's esophagus with dysplasia, and 63.84% in adenocarcinoma, with no statistical differences between groups. Concerning cells of the superficial layer, Barrett's esophagus with low grade dysplasia expressed focal positivity (p=0.0001 vs. no dysplasia); Barrett's esophagus with high grade dysplasia displayed diffuse positivity (p=0.0001 vs. no dysplasia and low grade dysplasia). A diffuse positivity was found in Barrett's esophagus with adenocarcinoma (p=0.0001 vs. no dysplasia and low grade dysplasia).

CONCLUSIONS

Further evaluation of cyclooxygenase 2, cell division cycle 2 and caudal-type homeobox transcription factor 2, in association with morphology, might help to improve the accuracy of diagnosis and be useful for the clinical-pathological assessment of patients with Barrett's esophagus.

Abnormal expression of biomarkers in incompletely ablated Barrett's esophagus

OBJECTIVE

The aim of this study was to evaluate expression of cancer risk-associated biomarkers in columnar epithelium at squamocolumnar junctions produced by an ablation procedure and proton pump inhibitors in incompletely ablated Barrett's esophagus (BE) patients that were nondysplastic prior to ablation.

SUMMARY BACKGROUND DATA

Ablation of BE to squamous epithelium is achievable by combining a re-injury method with acid suppression. We previously reported that, when there is complete ablation, the neo-squamous epithelium is normal histologically and in biomarker expression. However, squamous islands observed after prolonged use of PPIs were associated with abnormalities in p53 expression and Ki-67 labeling.

METHODS

Twenty-one nondysplastic BE cases with incomplete ablation were evaluated for the expression of Ki-67 (proliferation), cyclooxygenase-2 (COX-2), and p53 by immunohistochemistry.

RESULTS

Pre-ablation biopsies showed the normal staining patterns in columnar epithelium, ie, normal Ki-67 labeling, rare positive COX-2 staining of interstitial cells, and negative or mild staining for p53 in the majority of patients' biopsies. However, post-ablation biopsies demonstrated abnormal staining patterns in the glandular area at the new squamocolumnar junctions. In 13 of 21 post-ablation cases (62%), increased Ki-67 staining was seen in BE glands. In 8 of 21 patients (38%), increased COX-2 expression was seen in columnar epithelium. Similarly, in 8 of 21 post-ablation junctions (38%), there was increased p53 staining.

CONCLUSIONS

Our findings of increased expression of cancer-associated biomarkers in incompletely ablated BE patients raise a cautionary note regarding this procedure. We hypothesize that newly formed junctions contain cells undergoing replication, differentiation, etc, and are thus more susceptible to genomic damage.

Global Tumor RNA Expression in Early Establishment of Experimental Tumor Growth and Related Angiogenesis following Cox-Inhibition Evaluated by Microarray Analysis

Altered expression of COX-2 and overproduction of prostaglandins, particularly prostaglandin E2, are common in malignant tumors. Consequently, non-steroidal anti-inflammatory drugs (NSAIDs) attenuate tumor net growth, tumor related cachexia, improve appetite and prolong survival. We have also reported that COX-inhibition (indomethacin) interfered with early onset of tumor endothelial cell growth, tumor cell proliferation and apoptosis. It is however still unclear whether such effects are restricted to metabolic alterations closely related to eicosanoid pathways and corresponding regulators, or whether a whole variety of gene products are involved both up- and downstream effects of eicosanoids. Therefore, present experiments were performed by the use of an in vivo, intravital chamber technique, where micro-tumor growth and related angiogenesis were analyzed by microarray to evaluate for changes in global RNA expression caused by indomethacin treatment.

Indomethacin up-regulated 351 and down-regulated 1852 genes significantly (p < 0.01); 1066 of these genes had unknown biological function. Genes with altered expression occurred on all chromosomes.

Our results demonstrate that indomethacin altered expression of a large number of genes distributed among a variety of processes in the carcinogenic progression involving angiogenesis, apoptosis, cell-cycling, cell adhesion, inflammation as well as fatty acid metabolism and proteolysis. It remains a challenge to distinguish primary key alterations from secondary adaptive changes in transcription of genes altered by cyclooxygenase inhibition.

Incorporation of Nissen fundoplication in a rat model of duodenoesophageal reflux

BACKGROUND

Few in vivo models of esophageal reflux and fundoplication suitable for the study of the pathogenesis of Barrett's esophagus and esophageal cancer exist. We describe a modification of a rat model of duodenoesophageal reflux that incorporates Nissen fundoplication and uses it to study the role of fundoplication in ameliorating esophageal reflux.

METHODS

A previously described rat model of duodenoesophageal reflux was modified to include Nissen fundoplication. Reflux threshold (RT), defined as the gastric pressure required to cause gastroesophageal reflux during transgastric instillation of saline, was measured in 12 Sprague-Dawley rats at baseline, after cardiomyotomy with esophagogastroduodenal anastomosis (EGDA), after subsequent Nissen fundoplication, and, finally, after takedown of Nissen fundoplication (NF).

RESULTS

Cardiomyotomy with EGDA induced no significant change in RT compared with baseline (mean RT +/- SD: 4.0 +/- 1.9 mmHg and 6.0 +/- 2.5 mmHg, respectively, p = 0.741). Nissen fundoplication led to a 14-fold increase in RT (56.4 +/- 18.2 mmHg) compared with cardiomyotomy. RT pressure reverted to baseline levels after NF takedown (4.7 +/- 2.9 mmHg, p < 0.001). Antegrade esophageal flow was demonstrated without an increase in distal esophageal pressure after NF.

CONCLUSIONS

Nissen fundoplication creates a one-way antireflux mechanism that eliminates gastroesophageal reflux in this rat model. This modification of an in vivo model of duodenoesophageal reflux represents a unique opportunity to investigate the effect of NF on cardiomyotomy-induced reflux and distal esophageal exposure to duodenogastric refluxate, and could be useful in the study of the role of NF in preventing progression to BE and ECA.

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.

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

Previous studies from our laboratory and others have suggested that increased expression of cox-2 is important in the genesis of esophageal adenocarcinoma. In vitro studies suggest that cox-2 regulates expression of the anti-apoptotic protein bcl-2, thus possibly accounting for reduced apoptosis in carcinogenesis. The aim of this study was to investigate the relationship of these 2 genes in the development of Barrett's-associated adenocarcinoma. Histologic sections from endoscopic biopsies or esophagectomy specimens were classified as non-dysplastic Barrett's (n = 30), intraepithelial neoplasia (n = 12) and adenocarcinoma (n = 48). The desired tissue was isolated by laser capture microdissection and expression levels of cox-2 and bcl-2 were measured by quantitative real-time PCR (Taqman). Gene expression levels were compared to samples of the distal esophageal squamous epithelium (n = 55) and reflux-esophagitis (n = 25), without Barrett's or cancer. Expression of both bcl-2 and cox-2 were increased in non-dysplastic Barrett's (p = 0.0077, p = 0.0037), intraepithelial neoplasia (p = 0.0053, p = 0.0220) and adenocarcinoma (p < 0.0001, p < 0.0001) compared to squamous epithelium or reflux-esophagitis. Furthermore, there is a significant correlation between these two genes, especially in carcinoma (p < 0.0001).

Nonsteroidal anti-inflammatory drugs and the esophageal inflammation-metaplasia-adenocarcinoma sequence

Observational studies suggest that nonsteroidal anti-inflammatory drugs (NSAIDs) reduce the risk of esophageal adenocarcinoma, but it is not known at what stage they may act in the esophageal inflammation-metaplasia-adenocarcinoma sequence. In an all-Ireland case-control study, we investigated the relationship between the use of NSAIDs and risk of reflux esophagitis, Barrett's esophagus, and esophageal adenocarcinoma. Patients with esophageal adenocarcinoma, long-segment Barrett's esophagus and population controls were recruited from throughout Ireland. Esophagitis patients were recruited from Northern Ireland only. Data were collected on known and potential risk factors for esophageal adenocarcinoma and on the use of NSAIDs, including aspirin, at least 1 year before interview. Associations between use of NSAIDs and the stages of the esophageal inflammation-metaplasia-adenocarcinoma sequence were estimated by multiple logistic regression. In total, 230 reflux esophagitis, 224 Barrett's esophagus, and 227 esophageal adenocarcinoma and 260 population controls were recruited. Use of aspirin and NSAIDs was associated with a reduced risk of Barrett's esophagus [odds ratio [OR; 95% confidence interval (95% CI)], 0.53 (0.31-0.90) and 0.40 (0.19-0.81), respectively] and esophageal adenocarcinoma [OR (95% CI), 0.57 (0.36-0.93) and 0.58 (0.31-1.08), respectively]. Barrett's esophagus and esophageal adenocarcinoma patients were less likely than controls to have used NSAIDs. Selection or recall bias may explain these results and the results of previous observational studies indicating a protective effect of NSAIDs against esophageal adenocarcinoma. If NSAIDs have a true protective effect on the esophageal inflammation-metaplasia-adenocarcinoma sequence, they may act early in the sequence.

Cyclooxygenase-2 as a target for anticancer drug development

The two isoforms cyclooxygenase-1 and -2 catalyze the initial step in the formation of prostaglandins in a variety of pathophysiological processes. More recently their role in carcinogenesis has become more evident. They seem to influence apoptosis, angiogenesis, and invasion, and play a role in the production of carcinogens. Usually, a high level of COX-2 expression is found in cancer cells. However, low COX-2 expression is observed in some cancers like prostate or breast cancer. This phenomenon is quite surprising and should influence on clinical trial designs. Large epidemiological trials studying users and non-users of aspirin have shown that cyclooxygenase (COX) inhibitors and non-steroidal anti-inflammatory drugs (NSAIDs) could be of benefit against the development and growth of malignancies. Moreover, clinical trials in patients with familial adenomatosis polyposis syndrome have shown too the efficacy of non-selective COX inhibitors and recently also of selective COX-2 inhibitors in the reduction of the number and the size of colorectal polyps. However, a primary chemopreventive effect has not been demonstrated yet. NSAIDs are also supposed to have a preventive and growth inhibitory effect in extra-colonic epithelial malignancies. Several preclinical studies show promising results with combination treatments of either chemotherapy or radiotherapy with COX inhibitors. Preclinical studies with the simultaneous use of inhibitors of the epidermal growth factor receptor and COX-2 inhibitors have shown also promising results. Encouraging results with the first clinical trials combining chemotherapy with COX-2 inhibitors in patients with cancer in the advanced and neoadjuvant setting have recently been reported. However, NSAIDs effects in cancer cells are mediated not only by COX enzymes but also by interactions with downstream effectors of COX-2. Hence, we can state that targeting the COX-2 pathway is a promising strategy in the prevention and treatment of solid tumors. Ongoing trials are expected to answer - at least partly - the remaining questions concerning COX-2 and cancer.

Multistage carcinogenesis in Barrett's esophagus

The multistage carcinogenesis of esophageal adenocarcinoma is a process of clonal evolution within Barrett's esophagus neoplasms. The initiating event for Barrett's esophagus is unknown, but is associated with chronic gastric reflux which probably also promotes progression. Inactivation of both alleles of CDKN2A appear to be early events causing clonal expansion. Clones with TP53 inactivated expand if they have already inactivated CDKN2A. After TP53 has been inactivated, tetraploid and aneuploid clones tend to develop. The final events that lead to invasion and metastasis are unknown. Evolutionary biology provides important tools to understand clonal evolution in progression and cancer prevention.

The effects of esomeprazole combined with aspirin or rofecoxib on prostaglandin E2 production in patients with Barrett's oesophagus

BACKGROUND

Reducing mucosal cyclo-oxygenase-2 and prostaglandin E(2) production and suppressing intraoesophageal acid may be effective chemopreventive strategies in patients with Barrett's oesophagus.

AIM

To compare the effects of aspirin and rofecoxib when administered with esomeprazole on prostaglandin E(2) production, cyclo-oxygenase-2 expression and proliferating cell nuclear antigen expression in patients with Barrett's oesophagus.

METHODS

This exploratory, multicentre, randomized, open-label, four-way crossover study in 45 patients with Barrett's oesophagus evaluated prostaglandin E(2) content, proliferating cell nuclear antigen expression, and cyclo-oxygenase-2 expression after 10 days of sequential treatments with: esomeprazole 40 mg twice daily plus aspirin 325 mg once daily (E40 b.d. + A325); E40 b.d. plus rofecoxib 25 mg once daily (E40 b.d. + R25); E40 b.d.; and rofecoxib 25 mg once daily (R25).

RESULTS

Prostaglandin E(2) content reduction in Barrett's oesophagus tissue was significantly greater with E40 b.d. + A325 compared with E40 b.d. + R25, E40 b.d. or R25 (P < 0.05). All treatments containing E40 b.d. significantly decreased proliferating cell nuclear antigen expression from baseline (P < 0.05). None of the treatments significantly reduced cyclo-oxygenase-2 expression.

CONCLUSIONS

The combined treatment of esomeprazole 40 mg b.d. and aspirin 325 mg significantly decreased mucosal prostaglandin E(2) content and all treatments containing esomeprazole significantly reduced proliferating cell nuclear antigen expression in patients with Barrett's oesophagus.

Non-steroidal anti-inflammatory drugs and risk of neoplastic progression in Barrett's oesophagus: a prospective study

BACKGROUND

Aspirin and other non-steroidal anti-inflammatory drugs (NSAID) probably decrease the risk of colorectal neoplasia; however their effect on development of oesophageal adenocarcinoma is less clear. We aimed to assess the role of NSAID in the development of oesophageal adenocarcinoma and precursor lesions in people with Barrett's oesophagus--a metaplastic disorder that confers a high risk of oesophageal adenocarcinoma.

METHODS

We did a prospective study of the relation between duration, frequency, and recency of NSAID use and the risk of oesophageal adenocarcinoma, aneuploidy, and tetraploidy in a cohort of 350 people with Barrett's oesophagus followed for 20,770 person-months. We used proportional-hazards regression to calculate hazard ratios (HR) adjusted for age, sex, cigarette use, and anthropometric measurements.

FINDINGS

Median follow-up was 65.5 months (range 3.1-106.9). Compared with never users, HR for oesophageal adenocarcinoma (n=37 cases) in current NSAID users was 0.32 (95% CI 0.14-0.76), and in former users was 0.70 (0.31-1.58). 5-year cumulative incidence of oesophageal adenocarcinoma was 14.3% (95% CI 9.3-21.6) for never users, 9.7% (4.5-20.5) for former users, and 6.6% (3.1-13.6) for current NSAID users. When changes in NSAID use during follow up were taken into account, the associations were strengthened: HR for oesophageal adenocarcinoma for current users at baseline or afterwards was 0.20 (95% CI 0.10-0.41) compared with never users. Compared with never users, current NSAID users (at baseline and follow-up) had less aneuploidy (n=35 cases; 0.25 [0.12-0.54]) and tetraploidy (n=45 cases; 0.44 [0.22-0.87]).

INTERPRETATION

NSAID use might be an effective chemopreventive strategy, reducing the risk of neoplastic progression in Barrett's oesophagus.

Molecular biology of esophageal cancer in the genomics era

The incidence of esophageal adenocarcinoma is rising in the United States and Western countries. Significant differences exist between esophageal adenocarcinoma and squamous cell carcinoma in the molecular mechanisms responsible for the tumorigenesis process. State-of-the-art techniques such as gene microarrays and proteomics will greatly aid in the development of new therapies targeting specific molecular pathways,ultimately leading to improved survival in patients who have esophageal cancer.

Effect of inflammation on cyclooxygenase (COX)-2 expression in benign and malignant oesophageal cells

Chronic inflammation has been linked to carcinogenesis in various tissue sites. Barrett's oesophageal epithelium (BE) is a premalignant condition in which cyclooxygenase-2 (COX-2) levels are increased. However, it is not clear whether the primary stimulus for the high COX-2 levels is related to inflammation or malignancy. The effect of exogenous cytokines (IL-1beta, IL-10 and IL-13) on COX-2 expression was assessed by western blotting in three BE cancer cell lines (SEG-1, BIC-1 and OE33) and a squamous cancer cell line (OE21). Primary tissue was assessed from 17 patients with long BE segments, 13 oesophagitis, 30 oesophageal adenocarcinoma (EAC), and 40 normal oesophageal (NE) and duodenal (DU) controls. COX-2 protein expression was determined by western blotting and its tissue localization was examined using immunohistochemistry. COX-2 protein and the neutrophil marker myeloperoxidase (MPO) were quantified along BE segments. The leukocyte marker CD45 was used to identify any correlation between COX-2 expression and leukocyte cell distribution in EAC. IL-1beta induced COX-2 expression in SEG-1 cells (P < 0.05), whereas IL-10 and IL-13 had no effect. COX-2 protein levels were found to be increased in distal BE > proximal BE > oesophagitis > NE (P < 0.001). COX-2 expression in EAC was heterogeneous and the overall levels were not significantly increased. The increased COX-2 expression in distal BE was not associated with inflammation (MPO expression). In addition, there was no correlation between COX-2 and CD45 in AC. COX-2 protein expression in the oesophagus appears to be independent of the degree of inflammation.

The role of prostaglandins and other eicosanoids in the gastrointestinal tract

Nonsteroidal anti-inflammatory drugs (NSAIDs) are generally prescribed to ameliorate symptoms associated with acute pain and chronic inflammatory diseases such as arthritis. Recent epidemiologic studies and clinical trials indicate that use of NSAIDs and cyclooxygenase (COX)-2 selective inhibitors are associated with a reduced risk of certain malignancies, especially gastrointestinal cancer. The cyclooxygenase enzymes are the best known targets of NSAIDs; this diverse class of compounds blocks conversion of arachidonic acid to prostanoids. Prostaglandins and other eicosanoids derived from COX-1 and COX-2 are involved in a variety of physiologic and pathologic processes in the gastrointestinal tract. Recent efforts to identify the molecular mechanisms by which COX-2-derived prostanoids exert their proneoplastic effects have provided a rationale for the possible use of NSAIDs alone or in a combination with conventional or experimental anticancer agents for the treatment or prevention of gastrointestinal cancers.

New Molecular Concepts of Barrett’s Esophagus: Clinical Implications and Biomarkers

Barrett's esophagus (BE) represents the most serious histological consequence of gastroesophageal reflux disease (GERD) that develops in 5-10% of patients with GERD. Given that BE is the only known precursor to esophageal adenocarcinoma (EA), a systematic endoscopic biopsy protocol can detect EAs at an early stage. However, endoscopic and histopathological evaluation of BE are not adequate for effective screening of high risk patients. Therefore, molecular abnormalities associated with BE have been considered as surrogate markers and their use as such is proposed. Flow cytometry is the most useful adjunct to histology, and ploidy status of BE is an independent risk factor. Cyclin D1 overexpression is inversely correlated with survival in EA. C-erbB2 (+) patients have poorer prognosis. High plasma adenomatous polyposis coli levels correlate with reduced patient survival. p53 expression allows patient risk for EA stratification. Nuclear factor-kappaB overexpression inversely correlates with good response to adjuvant chemotherapy and radiotherapy in EA. Patients with cyclooxygenase-2 overexpression have reduced survival rates. Increased E-cadherin staining is associated with shorter survival in EA patients who received chemoradiotherapy. Finally, existing data cannot rule out a correlation between EA and colorectal tumors. Seventeen BE molecular alterations yielded noteworthy clinical implications. Apart from endoscopy and histology, these data allow for better risk stratification for patients with BE and for more efficient and timely therapeutic approaches.

Gastrin-induced cyclooxygenase-2 expression in Barrett's carcinogenesis

PURPOSE

Cyclooxygenase (COX)-2 has been causally implicated in carcinogenesis. The evidence for increased COX-2 in the malignant progression of Barrett's esophagus is contradictory. We hypothesize that COX-2 expression may be causally affected by the gastrin status via the cholecystokinin 2 (CCK(2)) receptor.

EXPERIMENTAL DESIGN

COX-2 and prostaglandin E(2) expression were evaluated by Western blotting and enzyme-linked immune assay in samples of squamous esophagus, Barrett's esophagus with varying degrees of dysplasia to adenocarcinoma, and normal duodenum. Differentiation status was evaluated by histopathology and villin expression. A longitudinal case-control study compared COX-2 in patients who progressed to adenocarcinoma with nonprogressors matched for age and length of follow-up. Messenger RNA levels of gastrin and CCK(2) receptor in biopsies and cell lines were evaluated by reverse transcription-PCR, and in vitro gastrin stimulation was conducted with and without inhibitors for CCK(2) (YM022) and COX-2 (NS-398). Cell proliferation was evaluated using minichromosome maintenance protein 2 (Mcm2) and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays.

RESULTS

COX-2 expression is significantly increased in Barrett's esophagus before dysplasia development. Expression is highly variable within Barrett's dysplasia and adenocarcinoma samples independent of differentiation status. In a longitudinal case-control study, the expression levels within patients increased over time, regardless of the degree of malignant progression. Biopsies from nondysplastic Barrett's esophagus expressed increased gastrin mRNA levels compared with other biopsies. Gastrin significantly induced COX-2, prostaglandin E(2), and cell proliferation in biopsies and cell lines. Gastrin-induced proliferation can be inhibited by YM022 and NS-398.

CONCLUSIONS

COX-2 is up-regulated early in the Barrett's metaplasia sequence. During carcinogenesis, gastrin is a significant determinant of COX-2 activity levels via the CCK(2) receptor.

Prognostic role of cyclooxygenase-2 expression in esophageal carcinoma

Cyclooxygenase-2 (COX-2) is involved in esophageal carcinogenesis, but its clinical significance is not clarified yet. The association of several clinicopathological parameters with the immunohistochemical expression of COX-2 was analyzed in paraffin-embedded esophageal cancer specimens. In adenocarcinomas, COX-2 upregulation showed to be a late event and in a multivariate analysis it was associated independently with a reduced survival after surgery compared with low COX-2 expressed tumors (P=0.02). Although, the expression was extensively high in well-differentiated parts of squamous cell carcinoma, it was not related with a poor outcome. This study supports further investigation of selective COX-2 inhibitors in these tumors.

Quantitative, tissue-specific analysis of cyclooxygenase gene expression in the pathogenesis of Barrett's adenocarcinoma

Cyclooxygenase (Cox-2) is implicated in the pathogenesis of many cancers including esophageal adenocarcinoma (EAC), whereas the role of the isoform Cox-1 in carcinogenesis is not well understood. To further elucidate the role of these factors in the development of EAC, we measured the gene expressions (mRNA levels) of Cox-2 and Cox-1 by real-time quantitative polymerase chain reaction (QRT-PCR) in tissues from normal esophagus with and without erosive gastroesophageal reflux disease (GERD), Barrett's esophagus (BE), dysplasia, adenocarcinoma, and in healthy gastric antrum. All tissues were purified by laser capture microdissection from endoscopic or surgical resection specimens. Median Cox-2 gene expression did not differ significantly among the esophageal control groups but was elevated 5-fold in BE, 8-fold in dysplasia and 16-fold in EAC compared to normal esophageal controls with no erosive GERD. Erosive GERD tissue had slightly higher median Cox-2 expression but Cox-2 expression in normal antrum was much higher than that in a normal esophagus, close to that of dysplasia. In contrast to that of Cox-2, Cox-1 expression was significantly decreased in all neoplastic tissues compared to normal controls. Cox-1 and Cox-2 expression varied over a wide range in the neoplastic tissues but over a relatively narrow range in the esophageal normal tissues. The occurrence of substantial alterations in Cox-1 and Cox-2 expression at the BE stage indicates that these are early events in the development of EAC. These results confirm the important role of Cox-2 amplification in the pathogenesis of esophageal adenocarcinoma, but the unexpected down-regulation of Cox-1 raises questions about its role in carcinogenesis.

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Barrett's oesophagus with predominant intestinal metaplasia correlates with superficial cyclo-oxygenase-2 expression, increased proliferation and reduced apoptosis: changes that are partially reversed by non-steroidal anti-inflammatory drugs usage

BACKGROUND

Cyclo-oxygenase-2 expression has been reported to play an important role in the metaplasia-dysplasia-carcinoma sequence in Barrett's oesophagus. However, the existence of cyclo-oxygenase-2 expressing cells in Barrett's epithelium is still uncertain.

AIM

To identify the cells that express cyclo-oxygenase-2 protein and to investigate the relationship between cyclo-oxygenase-2 expression and mucin-phenotype of Barrett's epithelium.

METHODS

Sections from 466 biopsy samples of Barrett's epithelium from 358 non-medicated patients were immunohistochemically examined for the cyclo-oxygenase-2 expression, mucin-phenotype, cell proliferation and apoptosis.

RESULTS

Cyclo-oxygenase-2 expression was detected in 71.0% of Barrett's epithelium biopsy samples. In Barrett's epithelium with the gastric predominant mucin-phenotype, cyclo-oxygenase-2 expression was mainly found in stromal and deep epithelial cells, whereas in intestinal predominant mucin-phenotype, it was mostly in superficial epithelial cell. A significant elevation of proliferating cell nuclear antigen index and suppression of apoptotic index was observed in Barrett's epithelium with superficial epithelial cyclo-oxygenase-2 expression. Neither such elevation of proliferating cell nuclear antigen index nor the suppression of apoptotic index could be found in chronic non-steroidal anti-inflammatory drugs users.

CONCLUSIONS

Barrett's epithelium with intestinal mucin and superficial epithelial cyclo-oxygenase-2 expression possess a higher proliferation potential, but this risk may be thwarted by non-steroidal anti-inflammatory drugs administration.

Nonsteroidal Anti-inflammatory Drug Use in the Prevention and Treatment of Squamous Cell Carcinoma

BACKGROUND

Nonsteroidal anti-inflammatory drugs are widely reported to inhibit carcinogenesis.

OBJECTIVE

The objective was to review the literature on nonsteroidal anti-inflammatory drugs in the prevention and treatment of cancer as it pertains to cutaneous squamous cell carcinoma.

METHODS

We searched MEDLINE and performed a review of all published data on nonsteroidal anti-inflammatory drugs and cutaneous oncogenesis.

RESULTS

In vitro and animal data strongly suggest a role for cyclooxygenase-2 in the formation of actinic keratoses and squamous cell carcinomas. Further observational studies and clinical trials are needed to assess their putative role in chemoprevention.

CONCLUSIONS

Nonsteroidal anti-inflammatory drugs have activity against squamous cell carcinomas in vitro and in animal models, as well as in precursor lesions of squamous cell carcinomas. Human trials using selective cyclooxygenase-2 inhibitors are currently in progress and should offer exciting information regarding the chemopreventative function of nonsteroidal anti-inflammatory drugs.

Acid increases proliferation via ERK and p38 MAPK-mediated increases in cyclooxygenase-2 in Barrett's adenocarcinoma cells

Cyclooxygenase-2 (COX-2) has been linked to neoplastic progression in Barrett's esophagus. Acid exposure has been shown both to activate the MAPK pathways and to increase COX-2 protein expression in Barrett's metaplasia, but it is not known whether these effects are interrelated. We hypothesized that acid-induced activation of the MAPK pathways mediates an increase in COX-2 expression in Barrett's esophagus, and we tested this hypothesis in a Barrett's-associated adenocarcinoma cell line (SEG-1). We exposed SEG-1 cells to acidic or neutral media in the presence and absence of two MAPK inhibitors: U-0126 (an ERK inhibitor) or SB-203580 (a p38 inhibitor). We quantitated COX-2 protein levels using an enzyme immunometric assay and COX-2 mRNA levels using real-time PCR. We also determined how acid affects the activity of the COX-2 promoter and mRNA stability. Compared with SEG-1 cells exposed to neutral media, acid-exposed cells exhibited a 2.8-fold increase in COX-2 mRNA levels within 30 min. Both U-0126 and SB-203580 attenuated the acid-induced increase in COX-2 mRNA. Acid significantly increased COX-2 protein expression and promoter activity, and both of these effects were abolished by treatment with U-0126 and SB-203580. Acid exposure also stabilized COX-2 mRNA levels, an effect that was abolished by U-0126 but not by SB-203580. We conclude that acid increases COX-2 expression through activation of the MAPK pathways. Acid-induced activation of both ERK and p38 causes a significant increase in COX-2 promoter activity, and acid-activated ERK stabilizes COX-2 mRNA. These findings suggest potential mechanisms whereby acid reflux might promote carcinogenesis in Barrett's esophagus.

Daily use of non-steroidal anti-inflammatory drugs is less frequent in patients with Barrett's oesophagus who develop an oesophageal adenocarcinoma

BACKGROUND

Non-steroidal anti-inflammatory drugs use may protect against development of oesophageal adenocarcinoma.

AIM

To define the consequences of non-steroidal anti-inflammatory drugs use in patients with Barrett's oesophagus.

METHODS

Records of all Barrett's oesophagus/oesophageal adenocarcinoma patients examined in Blackpool-Wyre-Fylde area were reviewed. All surviving patients completed validated questionnaires.

RESULTS

Use of non-steroidal anti-inflammatory drugs of any type and at any frequency was more prevalent in Barrett's oesophagus patients [147 (38%) Barrett's oesophagus vs. 30 (26%) oesophageal adenocarcinoma, P = 0.02]. Daily use of non-steroidal anti-inflammatory drugs was more prevalent in Barrett's oesophagus patients [88 (23%) Barrett's oesophagus vs. 14 (12%) oesophageal adenocarcinoma, P = 0.02], due to more prevalent consumption of non-aspirin non-steroidal anti-inflammatory drugs [48 (13%) Barrett's oesophagus vs. four (4%) oesophageal adenocarcinoma, P = 0.009]. There was no difference between the two groups in usage of either daily low-dose aspirin or of occasional non-steroidal anti-inflammatory drugs. In logistic regression analysis any use of non-steroidal anti-inflammatory drugs [odds ratio (OR) = 0571 (95% CI: 0.359-0.909), P = 0.018] and daily use of non-aspirin non-steroidal anti-inflammatory drugs [OR = 0.297 (95% CI: 0.097-0.911), P = 0.034] were significant protective factors. Non-steroidal anti-inflammatory drugs use did not affect the survival of oesophageal adenocarcinoma patients. Oesophageal adenocarcinoma and Barrett's oesophagus consuming non-steroidal anti-inflammatory drugs did not differ in upper gastrointestinal bleeding [26 (15%) non-steroidal anti-inflammatory drugs consumers vs. 29 (9%) non-consumers, P = 0.08], oesophageal ulcers [31 (18%) non-steroidal anti-inflammatory drug consumers vs. 49 (15%) non-consumers, P = 0.43] or stricturing [19 (11%) non-steroidal anti-inflammatory drug consumers vs. 41 (13%) non-consumers, P = 0.58].

CONCLUSIONS

(i) Daily use of non-steroidal anti-inflammatory drugs is more prevalent in Barrett's oesophagus than oesophageal adenocarcinoma patients, because of a more prevalent use of non-aspirin non-steroidal anti-inflammatory drugs. (ii) Use of non-steroidal anti-inflammatory drugs in Barrett's oesophagus patients is safe if acid suppression is adequate.

Infectivity-enhanced cyclooxygenase-2-based conditionally replicative adenoviruses for esophageal adenocarcinoma treatment

The employment of conditionally replicative adenoviruses (CRAd) constitutes a promising alternative for cancer treatment; however, in the case of esophageal adenocarcinoma (EAC) the lack of an appropriate tumor-specific promoter and relative resistance to adenovirus infection have hampered the construction of CRAds with clinically applicable specificity and efficacy. By combining transcriptional targeting with infectivity enhancement for CRAds, we generated novel cyclooxygenase-2 (Cox-2) promoter-controlled replicative viral agents for the treatment of EAC. We used infectivity enhancement based on incorporation of an RGD-4C motif into the HI loop of the adenoviral (Ad) fiber knob domain as well as replacement of the Ad5 knob with the Ad3 knob. The Cox-2 promoter was highly active in EAC, whereas showing no significant activity in Cox-2-negative cell lines and primary cells isolated from normal mouse esophagus and stomach. Evaluation of infectivity-enhanced vectors revealed that the transduction and virus-cell binding ability of Ad5/Ad3-chimera were significantly more efficient than that of unmodified and Arg-Gly-Asp (RGD)-modified vectors. All of the Cox-2 CRAds demonstrated replication and subsequent oncolysis in EAC cells but not in Cox-2-negative cells in vitro, thus confirming the dependence of their replication on the Cox-2 promoter activity. Ad5/Ad3 CRAds exhibited significantly improved oncolysis and progeny production compared with unmodified and RGD-modified vectors without sacrificing tumor selectivity. Whereas unmodified and RGD-modified CRAds showed insignificant therapeutic effect in vivo, Ad5/Ad3 CRAds remarkably suppressed tumor growth of established xenografts in mice. Thus, our studies have demonstrated that Ad5/Ad3-chimeric Cox-2 promoter-driven CRAds are selective and potent agents for the treatment of EAC.

Antiproliferative and apoptotic effects of rofecoxib on esophageal cancer in vitro1

BACKGROUND

The incidence of Barrett's adenocarcinoma has increased dramatically in the United States, whereas squamous cell carcinoma of the esophagus remains a worldwide problem. Cyclooxygenase (COX)-2 may play an important role in gastrointestinal carcinogenesis and is overexpressed in both Barrett's metaplasia and adenocarcinoma. We hypothesized that a selective and commercially available COX-2 inhibitor, rofecoxib (Vioxx), would inhibit growth of Barrett's adenocarcinoma and squamous cell carcinoma of the esophagus by apoptotic pathways. Additional comparison studies were performed with commercially available COX-2 and COX-1 inhibitors.

MATERIALS AND METHODS

Two esophageal adenocarcinoma cell lines (SEG-1 and BIC) and two esophageal squamous cell cancer lines (KYSE 150 and KYSE 410) were treated with rofecoxib at doses ranging from 8.0 to 125 microg/well. NS-398 (a COX-2 antagonist) and Catechin (a COX-1 antagonist) were also used at doses of 50 and 100 microM. Esophageal cell viability was measured by MTT at 24 and 72 h. Apoptosis was evaluated after 18 h of incubation with rofecoxib, NS398, and Catechin by flow cytometry via annexin V assay.

RESULTS

Rofecoxib, NS-398, and Catechin treatments all resulted in significant antiproliferative effects in both adenocarcinoma and squamous cell carcinoma of the esophagus in vitro. Substantial increases in apoptotic activity were also found in all cell lines.

CONCLUSIONS

Our findings suggest that COX-2 and COX-1 inhibition has potential to become an effective treatment for both histological variants of esophageal cancer. Further in vivo and human studies are warranted to evaluate the safety and clinical utility of these agents in patients with all cancers of the esophagus.