Hypoxia-inducible factor-1α mediates reflux-induced epithelial-mesenchymal plasticity in Barrett's oesophagus patients

INTRODUCTION

Epithelial-mesenchymal plasticity (EMP), the process through which epithelial cells acquire mesenchymal features, is needed for wound repair but also might contribute to cancer initiation. Earlier, in vitro studies showed that Barrett's cells exposed to acidic bile salt solutions (ABS) develop EMP. Now, we have (1) induced reflux oesophagitis in Barrett's oesophagus (BO) patients by stopping proton pump inhibitors (PPIs), (2) assessed their biopsies for EMP and (3) explored molecular pathways underlying reflux-induced EMP in BO cells and spheroids.

METHODS

15 BO patients had endoscopy with biopsies of Barrett's metaplasia while on PPIs, and 1 and 2 weeks after stopping PPIs; RNA-seq data were assessed for enrichments in hypoxia-inducible factors (HIFs), angiogenesis and EMP pathways. In BO biopsies, cell lines and spheroids, EMP features (motility) and markers (vascular endothelial growth factor (VEGF), ZEB1, miR-200a&b) were evaluated by morphology, migration assays, immunostaining and qPCR; HIF-1α was knocked down with siRNA or shRNA.

RESULTS

At 1 and/or 2 weeks off PPIs, BO biopsies exhibited EMP features and markers, with significant enrichment for HIF-1α, angiogenesis and EMP pathways. In BO cells, ABS induced HIF-1α activation, which decreased miR-200a&b while increasing VEGF, ZEB1 and motility; HIF-1α knockdown blocked these effects. After ABS treatment, BO spheroids exhibited migratory protrusions showing nuclear HIF-1α, increased VEGF and decreased miR-200a&b.

CONCLUSIONS

In BO patients, reflux oesophagitis induces EMP changes associated with increased HIF-1α signalling in Barrett's metaplasia. In Barrett's cells, ABS trigger EMP via HIF-1α signalling. Thus, HIF-1α appears to play a key role in mediating reflux-induced EMP that might contribute to cancer in BO.

TRIAL REGISTRATION NUMBER

NCT02579460.

Understanding the malignant potential of gastric metaplasia of the oesophagus and its relevance to Barrett's oesophagus surveillance: individual-level data analysis

OBJECTIVE

Whether gastric metaplasia (GM) of the oesophagus should be considered as Barrett's oesophagus (BO) is controversial. Given concern intestinal metaplasia (IM) may be missed due to sampling, the UK guidelines include GM as a type of BO. Here, we investigated whether the risk of misdiagnosis and the malignant potential of GM warrant its place in the UK surveillance.

DESIGN

We performed a thorough pathology and endoscopy review to follow clinical outcomes in a novel UK cohort of 244 patients, covering 1854 person years of follow-up. We complemented this with a comparative genomic analysis of 160 GM and IM specimens, focused on early molecular hallmarks of BO and oesophageal adenocarcinoma (OAC).

RESULTS

We found that 58 of 77 short-segment (<3 cm) GM (SS-GM) cases (75%) continued to be observed as GM-only across a median of 4.4 years of follow-up. We observed that disease progression in GM-only cases and GM+IM cases (cases with reported GM on some occasions, IM on others) was significantly lower than in the IM-only cases (Kaplan-Meier, p=0.03). Genomic analysis revealed that the mutation burden in GM is significantly lower than in IM (p<0.01). Moreover, GM does not bear the mutational hallmarks of OAC, with an absence of associated signatures and driver gene mutations. Finally, we established that GM found adjacent to OAC is evolutionarily distant from cancer.

CONCLUSION

SS-GM is a distinct entity from SS-IM and the malignant potential of GM is lower than IM. It is questionable whether SS-GM warrants inclusion in BO surveillance.

Dedicated service for Barrett's oesophagus surveillance endoscopy yields higher dysplasia detection and guideline adherence in a non-tertiary setting in the UK: a 5-year comparative cohort study

Objective

Barrett's oesophagus (BO) endoscopic surveillance is performed to varying quality, dedicated services may offer improved outcomes. This study compares a dedicated BO service to standard care, specifically dysplasia detection rate (DDR), guideline adherence and use of advanced imaging modalities in a non-tertiary setting.

Design/method

5-year retrospective comparative cohort study comparing a dedicated BO endoscopy service with surveillance performed on non-dedicated slots at a non-tertiary centre in the UK. All adult patients undergoing BO surveillance between 1 March 2016 and 1 March 2021 were reviewed and those who underwent endoscopy on a dedicated BO service run by endoscopists with training in BO was compared with patients receiving their BO surveillance on any other endoscopy list. Endoscopy reports, histology results and clinic letters were reviewed for DDR and British society of gastroenterology guideline adherence.

Results

921 BO procedures were included (678 patients). 574 (62%) endoscopies were on a dedicated BO list vs 348 (38%) on non-dedicated.DDR was significantly higher in the dedicated cohort 6.3% (36/568) vs 2.7% (9/337) (p=0.014). Significance was sustained when cases with indefinite for dysplasia were excluded: 4.9% 27/533 vs 0.9% 3/329 (p=0.002). Guideline adherence was significantly better on the dedicated endoscopy lists.Factors associated with dysplasia detection in regression analysis included visible lesion documentation (p=0.036), use of targeted biopsies (p=<0.001), number of biopsies obtained (p≤0.001).

Conclusions

A dedicated Barrett's service showed higher DDR and guideline adherence than standard care and may be beneficial pending randomised trial data.

Quality of life measures in dysplastic Barrett's oesophagus are comparable to patients with non-dysplastic Barrett's oesophagus and do not improve after endoscopic therapy

OBJECTIVE

Barrett's oesophagus (BO) is a precursor lesion, via dysplastic phases, to oesophageal adenocarcinoma. Although overall risk from BO is low, it has been shown to adversely affect health-related quality of life (HRQOL). The aim was to compare dysplastic BO patients' HRQOL pre-endoscopic therapy (pre-ET) and post-ET. The pre-ET BO group was also compared with other cohorts: non-dysplastic BO (NDBO), those with colonic polyps, gastro-oesophageal reflux disease (GORD) and healthy volunteers.

DESIGN

Participants in the pre-ET cohort were recruited prior to their endotherapy and HRQOL questionnaires provided pre-ET and post-ET. Wilcoxon rank test was used to compare the pre-ET and post-ET findings. The Pre-ET group was compared to the other cohorts' HRQOL results using multiple linear regression analysis.

RESULTS

Pre-ET group of 69 participants returned the questionnaires prior to and 42 post-ET. Both the pre-ET and post-ET group showed similar levels of cancer worry, despite the treatment. No statistical significance was found for symptoms scores, anxiety and depression or general health measures with the Short Form-36 (SF-36) Score. Education for the BO patients was overall lacking with many of the pre-ET group still reporting unanswered questions about their disease.The Pre-ET group was compared with NDBO group (N=379), GORD (N=132), colonic polyp patients (N=152) and healthy volunteers (N=48). Cancer worry was similar between the NDBO group and the Pre-ET group, despite their lower risk of progression. GORD patients had worse symptom scores from a reflux and heartburn perspective. Only the healthy group has significantly better scores in the SF-36 and improved hospital anxiety and depression scores.

CONCLUSION

These findings suggest that there is a need to improve HRQOL for patients with BO. This should include improved education and devising-specific patient-reported outcome measures for BO to capture relevant areas of HRQOL in future studies.

Cancer incidence and mortality risks in a large US Barrett's oesophagus cohort

OBJECTIVE

Barrett's oesophagus (BE) increases the risk of oesophageal adenocarcinoma by 10-55 times that of the general population, but no community-based cancer-specific incidence and cause-specific mortality risk estimates exist for large cohorts in the USA.

DESIGN

Within Kaiser Permanente Northern California (KPNC), we identified patients with BE diagnosed during 1995-2012. KPNC cancer registry and mortality files were used to estimate standardised incidence ratios (SIR), standardised mortality ratios (SMR) and excess absolute risks.

RESULTS

There were 8929 patients with BE providing 50 147 person-years of follow-up. Compared with the greater KPNC population, patients with BE had increased risks of any cancer (SIR=1.40, 95% CI 1.31 to 1.49), which slightly decreased after excluding oesophageal cancer. Oesophageal adenocarcinoma risk was increased 24 times, which translated into an excess absolute risk of 24 cases per 10 000 person-years. Although oesophageal adenocarcinoma risk decreased with time since BE diagnosis, oesophageal cancer mortality did not, indicating that the true risk is stable and persistent with time. Relative risks of cardia and stomach cancers were increased, but excess absolute risks were modest. Risks of colorectal, lung and prostate cancers were unaltered. All-cause mortality was slightly increased after excluding oesophageal cancer (SMR=1.24, 95% CI 1.18 to 1.31), but time-stratified analyses indicated that this was likely attributable to diagnostic bias. Cause-specific SMRs were elevated for ischaemic heart disease (SMR=1.39, 95% CI 1.18 to 1.63), respiratory system diseases (SMR=1.51, 95% CI 1.29 to 1.75) and digestive system diseases (SMR=2.20 95% CI 1.75 to 2.75).

CONCLUSIONS

Patients with BE had a persistent excess risk of oesophageal adenocarcinoma over time, although their absolute excess risks for this cancer, any cancer and overall mortality were modest.

In oesophageal squamous cells, nitric oxide causes S-nitrosylation of Akt and blocks SOX2 (sex determining region Y-box 2) expression

OBJECTIVE

Barrett's metaplasia might develop if GORD causes oesophageal squamous cells to convert into columnar cells. Acid and bile exposures upregulate columnar differentiation genes like CDX2 in oesophageal squamous cells, but it is not known if such exposures downregulate squamous differentiation genes like SOX2. In addition to acid and bile, patients with GORD also have high oesophageal concentrations of nitric oxide (NO). This study aims to determine how acid, bile salts and NO affect genes that influence oesophageal cell phenotype.

DESIGN

Oesophageal squamous cells from patients with Barrett's oesophagus were exposed to acidic bile salts or NOC-9 (an NO donor). SOX2, p63 (squamous transcription factor) and CDX2 mRNAs were measured by quantitative RT-PCR. SOX2 and its regulatory Akt pathway proteins were evaluated by western blotting. S-nitrosylation by NO was blocked by dithiothreitol. Immunohistochemistry for SOX2 was performed on the oesophagus of rats with surgically induced GORD which were fed diets with and without nitrite supplementation.

RESULTS

In oesophageal squamous cells, NO profoundly decreased SOX2 protein and caused a significantly greater decrease in SOX2 mRNA than did acidic bile salts. NO also decreased p63 and increased CDX2 expression. NO caused S-nitrosylation of Akt, blocking its phosphorylation. Akt pathway inhibition by LY294002 or Akt siRNA reduced SOX2 mRNA. Rats fed with nitrite-supplemented diets exhibited weaker SOX2 oesophageal staining than rats fed with normal diets.

CONCLUSIONS

In oesophageal squamous cells, NO blocks SOX2 expression through Akt S-nitrosylation. NO also increases CDX2 and decreases p63 expression. By triggering molecular events preventing squamous differentiation while promoting intestinal differentiation, NO might contribute to Barrett's pathogenesis.

Evolution of oesophageal adenocarcinoma from metaplastic columnar epithelium without goblet cells in Barrett's oesophagus

OBJECTIVE

Barrett's oesophagus commonly presents as a patchwork of columnar metaplasia with and without goblet cells in the distal oesophagus. The presence of metaplastic columnar epithelium with goblet cells on oesophageal biopsy is a marker of cancer progression risk, but it is unclear whether clonal expansion and progression in Barrett's oesophagus is exclusive to columnar epithelium with goblet cells.

DESIGN

We developed a novel method to trace the clonal ancestry of an oesophageal adenocarcinoma across an entire Barrett's segment. Clonal expansions in Barrett's mucosa were identified using cytochrome c oxidase enzyme histochemistry. Somatic mutations were identified through mitochondrial DNA sequencing and single gland whole exome sequencing.

RESULTS

By tracing the clonal origin of an oesophageal adenocarcinoma across an entire Barrett's segment through a combination of histopathological spatial mapping and clonal ordering, we find that this cancer developed from a premalignant clonal expansion in non-dysplastic ('cardia-type') columnar metaplasia without goblet cells.

CONCLUSION

Our data demonstrate the premalignant potential of metaplastic columnar epithelium without goblet cells in the context of Barrett's oesophagus.

Impact of surveillance for Barrett's oesophagus on tumour stage and survival of patients with neoplastic progression

OBJECTIVE

Endoscopic surveillance for Barrett's oesophagus (BO) is under discussion given the overall low incidence of neoplastic progression and lack of evidence that it prevents advanced oesophageal adenocarcinoma (OAC). The aim of this study was to evaluate the impact of endoscopic BO surveillance on tumour stage and survival of patients with neoplastic progression.

DESIGN

783 patients with BO of at least 2 cm were included in a multicentre prospective cohort and followed during surveillance according to the American College of Gastroenterology guidelines. Cases of high-grade dysplasia and OAC were identified during follow-up. OAC staging was performed according to the 7th UICC-AJCC classification. Survival data were collected and crosschecked using death and municipal registries. Data from patients with OAC in the general population were obtained from the Dutch cancer registry. We compared survival of patients with BO with neoplastic progression during surveillance with those of patients without neoplastic progression and patients with OAC in the general population.

RESULTS

53 patients with BO developed high-grade dysplasia or OAC during surveillance. Thirty-five (66%) were classified as stage 0, 14 (26%) as stage 1 and 4 (8%) as stage 2. OAC was diagnosed at an earlier stage during BO surveillance than in the general population (p<0.001). Survival of patients with BO with neoplastic progression was not significantly worse than those of patients without neoplastic progression and similar to survival of patients with stage 0 or stage 1 OAC in the general population.

CONCLUSIONS

OAC is detected at an earlier stage during BO surveillance than in the general population with good survival rates.

Barrett's oesophagus length is established at the time of initial endoscopy and does not change over time: results from a large multicentre cohort

OBJECTIVE

It is unclear whether Barrett's oesophagus (BO) length changes over time or whether the full length of the segment is established at the onset of disease recognition. The objectives of this study were to evaluate the association of age and BO length and to evaluate the changes in BO length over time.

DESIGN

This is a prospective, multicentre cohort study involving patients with BO from five centres. Patients were divided into groups based on the decade of initial diagnosis of BO. The mean BO length and the mean change in BO length were calculated for each age decade. The mean change in BO length was also calculated between the index endoscopy and the last surveillance endoscopy.

RESULTS

3635 patients with BO were included in the study: 87.8% men, 92.8% Caucasians, mean age 60.9 years and mean BO length 3.5 cm. The mean change in BO length was 0.9 cm. The mean BO length did not significantly change for each age category: <30 years (4.6 cm), 30-39.9 years (3.2 cm), 40-49.9 years (3.1 cm), 50-59.9 years (3.1 cm), 60-69.9 years (3.6 cm), 70-79.7 (4.0 cm) and >80 years (4.5 cm), p=0.47. On subgroup analysis of patients with non-dysplastic BO who had at least 1 year of endoscopic follow up, there was a significant decrease in mean change in BO length across age categories ranging from +1.7 to -0.8 cm, p=0.03.

CONCLUSIONS

There was no significant difference in BO length by age category in decades. In addition, the change in BO length from index to follow-up endoscopy was similar among patients >30 years. These findings suggest that a patient's BO segment length attains its full extent by the time of the initial endoscopic examination.

Surveillance in patients with long-segment Barrett's oesophagus: a cost-effectiveness analysis

OBJECTIVE

Surveillance is recommended for Barrett's oesophagus (BO) to detect early oesophageal adenocarcinoma (OAC). The aim of this study was to evaluate the cost-effectiveness of surveillance.

DESIGN

We included 714 patients with long-segment BO in a multicentre prospective cohort study and used a multistate Markov model to calculate progression rates from no dysplasia (ND) to low-grade dysplasia (LGD), high-grade dysplasia (HGD) and OAC. Progression rates were incorporated in a decision-analytic model, including costs and quality of life data. We evaluated different surveillance intervals for ND and LGD, endoscopic mucosal resection (EMR), radiofrequency ablation (RFA) and oesophagectomy for HGD or early OAC and oesophagectomy for advanced OAC. The incremental cost-effectiveness ratio (ICER) was calculated in costs per quality-adjusted life-year (QALY).

RESULTS

The annual progression rate was 2% for ND to LGD, 4% for LGD to HGD or early OAC and 25% for HGD or early OAC to advanced OAC. Surveillance every 5 or 4 years with RFA for HGD or early OAC and oesophagectomy for advanced OAC had ICERs of €5.283 and €62.619 per QALY for ND. Surveillance every five to one year had ICERs of €4.922, €30.067, €32.531, €41.499 and €75.601 per QALY for LGD. EMR prior to RFA was slightly more expensive, but important for tumour staging.

CONCLUSIONS

Based on a Dutch healthcare perspective and assuming a willingness-to-pay threshold of €35.000 per QALY, surveillance with EMR and RFA for HGD or early OAC, and oesophagectomy for advanced OAC is cost-effective every 5 years for ND and every 3 years for LGD.

Barrett's oesophagus: how should we manage it?

Endoscopic surveillance remains the core management of non-dysplastic Barrett's oesophagus, although questions regarding its efficacy in reducing mortality from oesophageal adenocarcinoma have yet to be definitively answered, and randomised trial data are awaited. One of the main goals of current research is to achieve risk stratification, identifying those at high risk of progression. The recent British Society of Gastroenterology (BSG) guidelines on surveillance have taken a step in this direction with interval stratification on clinicopathological grounds. The majority of Barrett's oesophagus remains undiagnosed, and this has led to investigation of methods of screening for Barrett's oesophagus, ideally non-endoscopic methods capable of reliably identifying dysplasia. Chemoprevention to prevent progression is currently under investigation, and may become a key component of future treatment. The availability of effective endotherapy means that accurate identification of dysplasia is more important than ever. There is now evidence to support intervention with radiofrequency ablation (RFA) for low-grade dysplasia (LGD), but recent data have emphasised the need for consensus pathology for LGD. Ablative treatment has become well established for high-grade dysplasia, and should be employed for flat lesions where there is no visible abnormality. Of the ablative modalities, RFA has the strongest evidence base. Endoscopic resection should be performed for all visible lesions, and is now the treatment of choice for T1a tumours. Targeting those with high-risk disease will, hopefully, lead to efficacious and cost-effective surveillance, and the trend towards earlier intervention to halt progression gives cause for optimism that this will ultimately result in fewer deaths from oesophageal adenocarcinoma.

British Society of Gastroenterology guidelines on the diagnosis and management of Barrett's oesophagus

These guidelines provide a practical and evidence-based resource for the management of patients with Barrett's oesophagus and related early neoplasia. The Appraisal of Guidelines for Research and Evaluation (AGREE II) instrument was followed to provide a methodological strategy for the guideline development. A systematic review of the literature was performed for English language articles published up until December 2012 in order to address controversial issues in Barrett's oesophagus including definition, screening and diagnosis, surveillance, pathological grading for dysplasia, management of dysplasia, and early cancer including training requirements. The rigour and quality of the studies was evaluated using the SIGN checklist system. Recommendations on each topic were scored by each author using a five-tier system (A+, strong agreement, to D+, strongly disagree). Statements that failed to reach substantial agreement among authors, defined as >80% agreement (A or A+), were revisited and modified until substantial agreement (>80%) was reached. In formulating these guidelines, we took into consideration benefits and risks for the population and national health system, as well as patient perspectives. For the first time, we have suggested stratification of patients according to their estimated cancer risk based on clinical and histopathological criteria. In order to improve communication between clinicians, we recommend the use of minimum datasets for reporting endoscopic and pathological findings. We advocate endoscopic therapy for high-grade dysplasia and early cancer, which should be performed in high-volume centres. We hope that these guidelines will standardise and improve management for patients with Barrett's oesophagus and related neoplasia.