COX-2 mRNA is increased in oesophageal mucosal cells by a proton pump inhibitor

Author version made available in accordance with the publisher's policy.Introduction: Barrett’s oesophagus develops in some individuals with gastro-oesophageal reflux, and is the precursor to oesophageal adenocarcinoma. Proton pump inhibitors (PPIs) suppress gastric acid production and are used to treat reflux. Clinical trials suggest that COX inhibitors might prevent oesophageal cancer, although PPIs could offset this by increasing COX-2 expression in Barrett’s oesophagus. To investigate this, we evaluated the impact of a PPI on COX expression in oesophageal mucosal cells. Methods: The effect of the PPI esomeprazole on COX-1 and COX-2 mRNA levels in oesophageal cells was determined. Oesophageal cell lines OE33 (adenocarcinoma derived) and HET-1A (immortalized squamous cells), and a control intestinal cell line - HT29 (colon carcinoma), were treated for 24 hours with increasing concentrations of the esomeprazole. Results: COX-2, but not COX-1, mRNA levels, dose dependently increased in OE33 and HET-1A cells vs. esomeprazole concentration. COX-2 mRNA levels did not increase in HT29 cells. Conclusions: Exposure to esomeprazole increases COX-2 mRNA in oesophageal cells. This might contribute to the lack of benefit for COX inhibitors for oesophageal cancer prevention in recent clinica

microRNAs and Esophageal Cancer - Implications for Pathogenesis and Therapy

Author version made available in accordance with the publisher's policy.There are several microRNAs that have been consistently reported to be differentially expressed in esophageal squamous cell carcinoma vs. normal squamous tissue, with prognostic associations for miR-21 (invasion, positive nodes, decreased survival), miR-143 (disease recurrence, invasion depth), and miR-375 (inversely correlated with advanced stage, distant metastasis, poor overall survival, and disease-free survival). There is also evidence that miR-375 regulates gene expression associated with resistance to chemotherapy. Hence, microRNA expression assays have the potential to provide clinically relevant information about prognosis and potential response to chemotherapy in patients with esophageal squamous cell carcinoma. Results are inconsistent, however, for microRNAs across different studies for esophageal adenocarcinoma (EAC) vs. its precursor lesion Barrett’s esophagus. These inconsistencies may partly result from pathological and/or molecular heterogeneity in both Barrett’s esophagus and EAC, but may also result from differences in study designs or different choices of comparator tissues. Despite these inconsistencies, however, several mRNA/protein targets have been identified, the cancer related biology of some of these targets is well understood, and there are clinico-pathological associations for some of these mRNA targets. MicroRNAs also have potential for use in therapy for esophageal cancers. The development of new delivery methods, such as minicells and autologous microvesicles, and molecular modifications such as the addition of aromatic benzene pyridine analogs, have facilitated the exploration of the effects of therapeutic microRNAs in vivo. These approaches are producing encouraging results, with one technology in a phase I/IIa clinical trial

Molecular biomarkers and ablative therapies for Barrett’s esophagus

Author version made available in accordance with the publisher's policy.Barrett’s esophagus is the major risk factor for esophageal adenocarcinoma. Endoscopic interventions which ablate Barrett’s esophagus mucosa lead to replacement with a new squamous (neosquamous) mucosa, but it can be difficult to achieve complete ablation. Knowing whether cancer is less likely to develop in neosquamous mucosa or residual Barrett’s esophagus after ablation is critical for determining the efficacy of treatment. This issue can be informed by assessing biomarkers that are associated with an increased risk of progression to adenocarcinoma. Although there are few post-ablation biomarker studies, evidence suggests that that neosquamous mucosa may have a reduced risk of adenocarcinoma in patients who have been treated for dysplasia or cancer, but some patients who do not have complete eradication of non-dysplastic Barrett’s esophagus may still be at risk. Biomarkers could be used to optimize endoscopic surveillance strategies following ablation, but this needs to be assessed by clinical studies and economic modeling

Ablation of Barrett's oesophagus: towards improved outcomes for oesophageal cancer?

This is the accepted version of the following article: Mayne, G. C., Bright, T., Hussey, D. J. and Watson, D. I. (2012), Ablation of Barrett's oesophagus: towards improved outcomes for oesophageal cancer?. ANZ Journal of Surgery, 82: 592–598, which has been published in final form at doi:10.1111/j.1445-2197.2012.06151.xBarrett's oesophagus is the major risk factor for oesophageal adenocarcinoma. The management of Barrett’s oesophagus entails treating reflux symptoms with acid-suppressing medication or surgery (fundoplication). However neither form of anti-reflux therapy produces predictable regression, or prevents cancer development. Patients with Barrett’s oesophagus usually undergo endoscopic surveillance which aims to identify dysplastic changes or cancer at its earliest stage, when treatment outcomes should be better. Alternative endoscopic interventions are now available and are suggested for the treatment of early cancer, and prevention of progression of Barrett’s oesophagus to cancer. Such treatments could minimize the risks associated with oesophagectomy. The current status of these interventions is reviewed. Various endoscopic interventions have been described, but with long term outcomes uncertain, they remain somewhat controversial. Radiofrequency ablation (RFA) of dysplastic Barrett’s oesophagus might reduce the risk of cancer progression, although cancer development has been reported after this treatment. Endoscopic mucosal resection (EMR) allows a 1.5 to 2 cm diameter piece of oesophageal mucosa to be removed. This provides better pathology for diagnosis and staging, and if the lesion is confined to the mucosa and fully excised, EMR can be curative. The combination of EMR and RFA has been used for multifocal lesions, but long term outcomes are unknown. The new endoscopic interventions for Barrett’s oesophagus and early oesophageal cancer have potential to improve clinical outcomes, although evidence which confirms superiority over oesphagectomy is limited. Longer term outcome data and data from larger cohorts is required to confirm the appropriateness of these procedure

A fixed-point algorithm for estimating amplification efficiency from a polymerase chain reaction dilution series

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.Background The polymerase chain reaction amplifies and quantifies small amounts of DNA. It is a cyclic process, during each cycle of which each strand of template DNA is copied with probability approaching one: the amount of DNA approximately doubles and this amount can be estimated fluorimetrically each cycle, producing a set of fluorescence values hereafter referred to as the amplification curve. Commonly the biological question of relevance is one of the ratio of DNA concentrations in two samples: a ratio that is deduced by comparing the two amplification curves, usually by way of a plot of fluorescence against cycle number. Central to this analysis is measuring the extent to which one amplification curve is shifted relative to the other, a measurement often accomplished by defining a threshold or quantification cycle, Cq, for each curve: the fractional cycle number at which fluorescence reaches some threshold or at which some other criterion (maximum slope, maximum rate of change of slope) is satisfied. We propose an alternative where position is measured relative to a reference curve; position equates to the cycle shift which maximizes the correlation between the reference and the observed fluorescence sequence. A key parameter of the reference curve is obtained by fixed-point convergence. Results We consider the analysis of dilution series constructed for the estimation of qPCR amplification efficiency. The estimate of amplification efficiency is based on the slope of the regression line when the Cq is plotted against the logarithm of dilution. We compare the approach to three commonly used methods for determining Cq; each is applied to publicly accessible calibration data sets, and to ten from our own laboratory. As in the established literature we judge their relative merits both from the standard deviation of the slope of the calibration curve, and from the variance in Cq for replicate fluorescence curves. Conclusions The approach does not require modification of experimental protocols, and can be applied retrospectively to existing data. We recommend that it be added to the methodological toolkit with which laboratories interpret their real-time PCR data. Keywords: qPCR; Fixed-point; Amplification efficienc

Simplified Algorithms for Determining Cycle Shift between qPCR Fluorescence Curves

This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.The polymerase chain reaction is a central component of current molecular biology. It is a cyclic process, in each early cycle of which the template DNA approximately doubles. An indicator which fluoresces when bound to DNA quantifies the DNA present at the end of each cycle, giving rise to a fluorescence curve which is characteristically sigmoid in shape. The fluorescence curve quantifies the amount of DNA initially present; the more the initial DNA, the earlier the rise in the fluorescence. Accordingly the amount of DNA initially present in two samples can be compared: the sample with the less DNA gives rise to a relatively delayed fluorescence curve and the ratio of the DNAs can be deduced from the separation of the curves. There is, however, a second determinant of this separation, the fold increase in DNA per cycle: ideally a twofold increase but frequently less. Current guidelines recommend that this be determined experimentally by carrying out PCR on a series of dilutions. If the value of the fold increase is known, then the algorithm for determining the separation can be reduced to a relatively simple computation, rather than employing a multidimensional nonlinear optimization such as the Marquardt-Levenberg as currently employed

Can miRNA profiling allow us to determine which patients with esophageal cancer will respond to chemoradiotherapy?

Author version made available in accordance with the publisher's policy.Evaluation of: Ko MA, Zehong G, Virtanen C, et al.. MicroRNA Expression Profiling of Esophageal Cancer Before and After Induction Chemoradiotherapy. Ann Thorac Surg. 94(4),1094-1103 (2012). Most patients undergoing surgery for esophageal cancer are treated before surgery with chemotherapy and radiotherapy. However, some tumors respond poorly to these treatments. Ko and colleagues profiled microRNA levels in esophageal cancers from patients who did vs. did not respond to chemoradiotherapy. A large number of microRNAs were differentially expressed between responders vs. non-responders, and patients with either decreased miR-135b or increased miR-145 expression in cancer tissue had improved disease free survival. Although this study has several limitations, including a mixed cohort of patients with adenocarcinoma and squamous cell carcinoma, and the absence of a validation set of patients, the results do suggest that a microRNA profiling approach may be able to circumvent one of the primary challenges for biomarker development, molecular heterogeneity

Accuracy of identification of tissue types in endoscopic esophageal mucosal biopsies used for molecular biology studies

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博士（学術）神戸大

Metallothionien 3 expression is frequently down-regulated in oesophageal squamous cell carcinoma by DNA methylation

BACKGROUND: Metallothionein 3 (MT3) inhibits growth in a variety of cell types. We measured MT3 gene expression by RT-PCR, and DNA methylation in the MT3 promoter by combined bisulphite restriction analysis, in four oesophageal cancer cell lines and the resected oesophagus from 64 patients with oesophageal squamous cell carcinoma (SCC). RESULTS: MT3 expression was not detected in one of the four oesophageal cell lines. The MT3 promoter was methylated in all of the oesophageal cell lines, but the degree of methylation was greater in the non-expressing cell line. After treatment with 5-aza-2'-deoxycytidine there was a reduction in the degree of methylation, and an increase in MT3 expression, in each of the cell lines (p < 0.01). Methylation was detected in 52% (33 of 64) of primary SCC and 3% (2 of 62) of histologically normal resection margins. MT3 expression was measured in 29 tumours, 17 of which had methylation of MT3. The expression of MT3 was significantly less in the methylated tumours compared to either the unmethylated tumours (p = 0.03), or the matched margin (p = 0.0005). There was not a significant difference in MT3 expression between the tumour and the margin from patients with unmethylated tumour. No correlations were observed between methylation of MT3 and survival time, patient age, gender, smoking or drinking history, tumour stage, volume, or lymph node involvement. CONCLUSION: We conclude that MT3 expression is frequently down-regulated in oesophageal SCC, by DNA methylation, but that this is not a prognostic indicator