HIF-1alpha protein expression is associated with the environmental inflammatory reaction in Barrett's metaplasia

Gastro-Esophageal Junction Precancerosis: Histological Diagnostic Approach and Pathogenetic Insights

Barrett's esophagus (BE) was initially defined in the 1950s as the visualization of gastric-like mucosa in the esophagus. Over time, the definition has evolved to include the identification of goblet cells, which confirm the presence of intestinal metaplasia within the esophagus. Chronic gastro-esophageal reflux disease (GERD) is a significant risk factor for adenocarcinoma of the esophagus, as intestinal metaplasia can develop due to GERD. The development of adenocarcinomas related to BE progresses in sequence from inflammation to metaplasia, dysplasia, and ultimately carcinoma. In the presence of GERD, the squamous epithelium changes to columnar epithelium, which initially lacks goblet cells, but later develops goblet cell metaplasia and eventually dysplasia. The accumulation of multiple genetic and epigenetic alterations leads to the development and progression of dysplasia. The diagnosis of BE requires the identification of intestinal metaplasia on histologic examination, which has thus become an essential tool both in the diagnosis and in the assessment of dysplasia's presence and degree. The histologic diagnosis of BE dysplasia can be challenging due to sampling error, pathologists' experience, interobserver variation, and difficulty in histologic interpretation: all these problems complicate patient management. The development and progression of Barrett's esophagus (BE) depend on various molecular events that involve changes in cell-cycle regulatory genes, apoptosis, cell signaling, and adhesion pathways. In advanced stages, there are widespread genomic abnormalities with losses and gains in chromosome function, and DNA instability. This review aims to provide an updated and comprehensible diagnostic approach to BE based on the most recent guidelines available in the literature, and an overview of the pathogenetic and molecular mechanisms of its development.

Cross-talk between the microbiome and chronic inflammation in esophageal cancer: potential driver of oncogenesis

Esophageal cancer (EC) is frequently considered a lethal malignancy and is often identified at a later stage. It is one of the major causes of cancer-related deaths globally. The conventional treatment methods like chemotherapy, radiotherapy, and surgery offer limited efficacy and poor clinical outcome with a less than 25% 5-year survival rate. The poor prognosis of EC persists despite the growth in the development of diagnostic and therapeutic modalities to treat EC. This underlines the need to elucidate the complex molecular mechanisms that drive esophageal oncogenesis. Apart from the role of the tumor microenvironment and its structural and cellular components in tumorigenesis, mounting evidence points towards the involvement of the esophageal microbiome, inflammation, and their cross-talk in promoting esophageal cancer. The current review summarizes recent research that delineates the underlying molecular mechanisms by which the microbiota and inflammation promote the pathophysiology of esophageal cancer, thus unraveling targets for potential therapeutic intervention.

Spectral Endoscopy Enhances Contrast for Neoplasia in Surveillance of Barrett's Esophagus

Early detection of esophageal neoplasia enables curative endoscopic therapy, but the current diagnostic standard of care has low sensitivity because early neoplasia is often inconspicuous with conventional white-light endoscopy. Here, we hypothesized that spectral endoscopy could enhance contrast for neoplasia in surveillance of patients with Barrett's esophagus. A custom spectral endoscope was deployed in a pilot clinical study of 20 patients to capture 715 in vivo tissue spectra matched with gold standard diagnosis from histopathology. Spectral endoscopy was sensitive to changes in neovascularization during the progression of disease; both non-dysplastic and neoplastic Barrett's esophagus showed higher blood volume relative to healthy squamous tissue (P = 0.001 and 0.02, respectively), and vessel radius appeared larger in neoplasia relative to non-dysplastic Barrett's esophagus (P = 0.06). We further developed a deep learning algorithm capable of classifying spectra of neoplasia versus non-dysplastic Barrett's esophagus with high accuracy (84.8% accuracy, 83.7% sensitivity, 85.5% specificity, 78.3% positive predictive value, and 89.4% negative predictive value). Exploiting the newly acquired library of labeled spectra to model custom color filter sets identified a potential 12-fold enhancement in contrast between neoplasia and non-dysplastic Barrett's esophagus using application-specific color filters compared with standard-of-care white-light imaging (perceptible color difference = 32.4 and 2.7, respectively). This work demonstrates the potential of endoscopic spectral imaging to extract vascular properties in Barrett's esophagus, to classify disease stages using deep learning, and to enable high-contrast endoscopy. SIGNIFICANCE: The results of this pilot first-in-human clinical trial demonstrate the potential of spectral endoscopy to reveal disease-associated vascular changes and to provide high-contrast delineation of neoplasia in the esophagus. GRAPHICAL ABSTRACT: http://cancerres.aacrjournals.org/content/canres/81/12/3415/F1.large.jpg.

Hypoxia and its impact on the tumour microenvironment of gastroesophageal cancers

The malfeasant role of the hypoxic tumour microenvironment (TME) in cancer progression was recognized decades ago but the exact mechanisms that augment the hallmarks of cancer and promote treatment resistance continue to be elucidated. Gastroesophageal cancers (GOCs) represent a major burden of worldwide disease, responsible for the deaths of over 1 million people annually. Disentangling the impact of hypoxia in GOCs enables a better overall understanding of the disease pathogenesis while shining a light on novel therapeutic strategies and facilitating precision treatment approaches with the ultimate goal of improving outcomes for patients with these diseases. This review discusses the underlying principles and processes of the hypoxic response and the effect of hypoxia in promoting the hallmarks of cancer in the context of GOCs. We focus on its bidirectional influence on inflammation and how it drives angiogenesis, innate and adaptive immune evasion, metastasis, and the reprogramming of cellular bioenergetics. The contribution of the hypoxic GOC TME to treatment resistance is examined and a brief overview of the pharmacodynamics of hypoxia-targeted therapeutics is given. The principal methods that are used in measuring hypoxia and how they may enhance prognostication or provide rationale for individually tailored management in the case of tumours with significant hypoxic regions are also discussed.

Esophageal Microenvironment: From Precursor Microenvironment to Premetastatic Niche

Esophageal cancer (EC) is the sixth most deadly cancer, and its incidence is still increasing year by year. Although the researches on the molecular mechanisms of EC have been widely carried out and incremental progress has been made, its overall survival rate is still low. There is cumulative evidence showing that the esophageal microenvironment plays a vital role in the development of EC. In precancerous lesions of the esophagus, high-risk environmental factors can promote the development of precancerous lesions by inducing the production of inflammatory factors and the recruitment of immune cells. In the tumor microenvironment, tumor-promoting cells can inhibit anti-tumor immunity and promote tumor progression through a variety of pathways, such as bone marrow-derived suppressor cells (MDSCs), tumor-associated fibroblasts (CAFs), and regulatory T cells (Tregs). The formation of extracellular hypoxia and acidic microenvironment and the change of extracellular matrix stiffness are also important factors affecting tumor progression and metastasis. Simultaneously, primary tumor-derived cytokines and bone marrow-derived immune cells can also promote the formation of pre-metastasis niche of EC lymph nodes, which are beneficial to EC lymph node metastasis. Further research on the specific mechanism of these processes in the occurrence, development, and metastasis of each EC subtype will support us to grasp the overall pre-cancerous prevention, targeted treatment, and metastatic assessment of EC.

HIF-1α acts as a molecular target for simvastatin cytotoxicity in B16.F10 melanoma cells cultured under chemically induced hypoxia

Our previous studies reported that one of the main mechanisms of the antitumor activity of simvastatin (SIM) in B16.F10 murine melanoma cells was associated with strong suppression of the constitutive cell production of the α subunit of the heterodimeric transcription factor hypoxia-inducible factor (HIF)-1. Thus, the present study aimed to broaden this finding under hypoxic conditions induced by incubation of B16.F10 cells with cobalt chloride, when the constitutive production of HIF-1α in these melanoma cells is amplified by inducible expression of this factor. The data demonstrated that the SIM antiproliferative effects on melanoma cells were mediated mainly via strong suppressive actions on the B16.F10 cell capacity to support tumor angiogenesis and inflammation, as a result of a high inhibition of the inducible expression of HIF-1α. However, the constitutive expression of HIF-1α was not affected by SIM, probably due to the lack of effect of this statin on nuclear factor-κB production in B16.F10 cancer cells at the concentration tested. Additionally, the present study noted slight reducing effects of SIM on tumor oxidative stress, which may contribute to the main inhibitory action of this statin on HIF-1α production in hypoxic tumor cells. Collectively, these data are valuable for future anticancer strategies based on SIM administration in combination with cytotoxic drugs that are able to counteract the constitutive expression of HIF-1α in tumors.

Examining the connectivity between different cellular processes in the Barrett tissue microenvironment

In Barrett associated tumorigenesis, oxidative phosphorylation and glycolysis are reprogrammed early in the disease sequence and act mutually to promote disease progression. However, the link between energy metabolism and its connection with other central cellular processes within the Barrett microenvironment is unknown. The aim of this study was to examine the relationship between metabolism (ATP5B/GAPDH), hypoxia (HIF1α), inflammation (IL1β/SERPINA3), p53 and obesity status using in-vivo and ex-vivo models of Barrett oesophagus. At the protein level, ATP5B (r = 0.71, P < 0.0001) and p53 (r = 0.455, P = 0.015) were found to be strongly associated with hypoxia. In addition, levels of ATP5B (r = 0.53, P = 0.0031) and GAPDH (r = -0.39, P = 0.0357) were positively associated with p53 expression. Moreover, we demonstrate that ATP5B (r = 0.8, P < 0.0001) and GAPDH (r = 0.43, P = 0.022) were positively associated with IL1β expression. Interestingly, obesity was negatively associated with oxidative phosphorylation (r = -0.6016, P = 0.0177) but positively associated with glycolysis (r = 0.743, P = 0.0015). Comparable correlations were exhibited in the ex-vivo explant tissue between metabolism, p53, hypoxia, inflammation and angiogenesis (P < 0.05). We have shown that metabolism is closely linked with many cellular processes in the Barrett tissue microenvironment.

TissueCypher(™): A systems biology approach to anatomic pathology

Background:

Current histologic methods for diagnosis are limited by intra- and inter-observer variability. Immunohistochemistry (IHC) methods are frequently used to assess biomarkers to aid diagnoses, however, IHC staining is variable and nonlinear and the manual interpretation is subjective. Furthermore, the biomarkers assessed clinically are typically biomarkers of epithelial cell processes. Tumors and premalignant tissues are not composed only of epithelial cells but are interacting systems of multiple cell types, including various stromal cell types that are involved in cancer development. The complex network of the tissue system highlights the need for a systems biology approach to anatomic pathology, in which quantification of system processes is combined with informatics tools to produce actionable scores to aid clinical decision-making.

Aims:

Here, we describe a quantitative, multiplexed biomarker imaging approach termed TissueCypher™ that applies systems biology to anatomic pathology. Applications of TissueCypher™ in understanding the tissue system of Barrett's esophagus (BE) and the potential use as an adjunctive tool in the diagnosis of BE are described.

Patients and Methods:

The TissueCypher™ Image Analysis Platform was used to assess 14 epithelial and stromal biomarkers with known diagnostic significance in BE in a set of BE biopsies with nondysplastic BE with reactive atypia (RA, n = 22) and Barrett's with high-grade dysplasia (HGD, n = 17). Biomarker and morphology features were extracted and evaluated in the confirmed BE HGD cases versus the nondysplastic BE cases with RA.

Results:

Multiple image analysis features derived from epithelial and stromal biomarkers, including immune biomarkers and morphology, showed significant differences between HGD and RA.

Conclusions:

The assessment of epithelial cell abnormalities combined with an assessment of cellular changes in the lamina propria may serve as an adjunct to conventional pathology in the assessment of BE.

Differential nucleobase protection against 5-fluorouracil toxicity for squamous and columnar cells: implication for tissue function and oncogenesis

Purpose The goal of these studies was to test if local excess of a normal nucleobase substrate prevents the toxicity of protracted 5FU exposure used in human cancer treatment. Methods Messenger RNA expression studies were performed of 5FU activating enzymes in human colon cancer cells lines (CaCo-2, HT-29), primary human gingival cells (HEGP), and normal esophageal and gastric clinical tissue samples. Excess nucleobase was then used in vitro to protect cells from 5FU toxicity. Results Pyrimidine salvage pathways predominate in squamous cells of the gingiva (HEGP) and esophageal tissue. Excess salvage nucleobase uracil but not adenine prevented 5FU toxicity in HEGP cells. Pyrimidine de novo synthesis predominates in columnar Caco-2, HT-29 and gastric tissue. Excess nucleobase adenine but not uracil prevented 5FU toxicity to Caco-2 and HT-29 cells. Conclusion The directed application of the normal nucleobase uracil to the squamous cells of the oral mucosa and palms and soles together with the delivery of the normal nucleobase adenine to the columnar cells of the GI tract may enable the safe delivery of higher 5FU dose intensity. These results also suggest a feature of tissue function where squamous cells grow largely by recycling overlying tissue cell components. Columnar cells use absorbed surface nutrients for de novo growth. A disruption of this tissue function can result in growth derived from an underlying nutrient source. That change would also cause the loss of the region of cell turnover at the tissue surface. Subsequent cell proliferation with limiting nutrient availability could promote oncogenesis in such initiated tissue.

The role of inflammation in cancer of the esophagus

Esophageal adenocarcinoma is the eighth most common malignancy worldwide. The overall prognosis is poor, with 5-year survival ranges of approximately 15-25%, and 30-50% for patients who can be treated with curative intent. There has been a marked increase in incidence of esophageal adenocarcinoma over the last 30 years, with chronic and severe reflux, diet and obesity identified as principal factors fuelling this rise in the West. Esophageal adenocarcinoma is an exemplar model of an inflammation-associated cancer. The key molecular pathways driving tumor development and influencing tumor biology are the subject of considerable research efforts, and is the principal focus of this review. In addition, the diverse range of changes occurring in the local immune response, tissue microenvironment, metabolic profile, intracellular signaling mechanisms and microRNA signatures are discussed, as well as novel targeted therapies.

Emerging avenues linking inflammation and cancer

The role of inflammation in carcinogenesis has been extensively investigated and well documented. Many biochemical processes that are altered during chronic inflammation have been implicated in tumorigenesis. These include shifting cellular redox balance toward oxidative stress; induction of genomic instability; increased DNA damage; stimulation of cell proliferation, metastasis, and angiogenesis; deregulation of cellular epigenetic control of gene expression; and inappropriate epithelial-to-mesenchymal transition. A wide array of proinflammatory cytokines, prostaglandins, nitric oxide, and matricellular proteins are closely involved in premalignant and malignant conversion of cells in a background of chronic inflammation. Inappropriate transcription of genes encoding inflammatory mediators, survival factors, and angiogenic and metastatic proteins is the key molecular event in linking inflammation and cancer. Aberrant cell signaling pathways comprising various kinases and their downstream transcription factors have been identified as the major contributors in abnormal gene expression associated with inflammation-driven carcinogenesis. The posttranscriptional regulation of gene expression by microRNAs also provides the molecular basis for linking inflammation to cancer. This review highlights the multifaceted role of inflammation in carcinogenesis in the context of altered cellular redox signaling.

Interactions between environmental factors and polymorphisms in angiogenesis pathway genes in esophageal adenocarcinoma risk: a case-only study

BACKGROUND

Gastroesophageal reflux disease (GERD), higher body mass index (BMI), smoking, and genetic variants in angiogenic pathway genes have been individually associated with increased risk of esophageal adenocarcinoma. However, how angiogenic gene polymorphisms and environmental factors jointly affect esophageal adenocarcinoma development remains unclear.

METHODS

By using a case-only design (n = 335), the authors examined interactions between 141 functional/tagging angiogenic single nucleotide polymorphisms (SNPs) and environmental factors (GERD, BMI, smoking) in modulating esophageal adenocarcinoma risk. Gene-environment interactions were assessed by a 2-step approach. First, the authors applied random forest to screen for important SNPs that had either main or interaction effects. Second, they used case-only logistic regression to assess the effects of gene-environment interactions on esophageal adenocarcinoma risk, adjusting for covariates and false-discovery rate.

RESULTS

Random forest analyses identified 3 sets of SNPs (17 SNPs-GERD, 26 SNPs-smoking, and 34 SNPs-BMI) that had the highest importance scores. In subsequent logistic regression analyses, interactions between 2 SNPs (rs2295778 of HIF1AN, rs13337626 of TSC2) and GERD, 2 SNPs (rs2295778 of HIF1AN, rs2296188 of VEGFR1) and smoking, and 7 SNPs (rs2114039 of PDGRFA, rs2296188 of VEGFR1, rs11941492 of VEGFR1, rs17708574 of PDGFRB, rs7324547 of VEGFR1, rs17619601 of VEGFR1, and rs17625898 of VEGFR1) and BMI were significantly associated with esophageal adenocarcinoma development (all false-discovery rates ≤0.10). Moreover, these interactions tended to have SNP dose-response effects for increased esophageal adenocarcinoma risk with increasing number of combined risk genotypes.

CONCLUSIONS

These findings suggest that genetic variations in angiogenic genes may modify esophageal adenocarcinoma susceptibility through interactions with environmental factors in an SNP dose-response manner.

The differential disease regulome

Background

Transcription factors in disease-relevant pathways represent potential drug targets, by impacting a distinct set of pathways that may be modulated through gene regulation. The influence of transcription factors is typically studied on a per disease basis, and no current resources provide a global overview of the relations between transcription factors and disease. Furthermore, existing pipelines for related large-scale analysis are tailored for particular sources of input data, and there is a need for generic methodology for integrating complementary sources of genomic information.

Results

We here present a large-scale analysis of multiple diseases versus multiple transcription factors, with a global map of over-and under-representation of 446 transcription factors in 1010 diseases. This map, referred to as the differential disease regulome, provides a first global statistical overview of the complex interrelationships between diseases, genes and controlling elements. The map is visualized using the Google map engine, due to its very large size, and provides a range of detailed information in a dynamic presentation format.

The analysis is achieved through a novel methodology that performs a pairwise, genome-wide comparison on the cartesian product of two distinct sets of annotation tracks, e.g. all combinations of one disease and one TF.

The methodology was also used to extend with maps using alternative data sets related to transcription and disease, as well as data sets related to Gene Ontology classification and histone modifications. We provide a web-based interface that allows users to generate other custom maps, which could be based on precisely specified subsets of transcription factors and diseases, or, in general, on any categorical genome annotation tracks as they are improved or become available.

Conclusion

We have created a first resource that provides a global overview of the complex relations between transcription factors and disease. As the accuracy of the disease regulome depends mainly on the quality of the input data, forthcoming ChIP-seq based binding data for many TFs will provide improved maps. We further believe our approach to genome analysis could allow an advance from the current typical situation of one-time integrative efforts to reproducible and upgradable integrative analysis. The differential disease regulome and its associated methodology is available at http://hyperbrowser.uio.no.