Altered expression of TFF-1 and CES-2 in Barrett's Esophagus and associated adenocarcinomas

Exploiting Matrix Stiffness to Overcome Drug Resistance

Drug resistance is arguably one of the biggest challenges facing cancer research today. Understanding the underlying mechanisms of drug resistance in tumor progression and metastasis are essential in developing better treatment modalities. Given the matrix stiffness affecting the mechanotransduction capabilities of cancer cells, characterization of the related signal transduction pathways can provide a better understanding for developing novel therapeutic strategies. In this review, we aimed to summarize the recent advancements in tumor matrix biology in parallel to therapeutic approaches targeting matrix stiffness and its consequences in cellular processes in tumor progression and metastasis. The cellular processes governed by signal transduction pathways and their aberrant activation may result in activating the epithelial-to-mesenchymal transition, cancer stemness, and autophagy, which can be attributed to drug resistance. Developing therapeutic strategies to target these cellular processes in cancer biology will offer novel therapeutic approaches to tailor better personalized treatment modalities for clinical studies.

Strong Annexin A10 Expression Supports a Pancreatic Primary and Combined Annexin A10, Claudin 18, and SOX2 Expression Supports an Esophagogastric Origin in Carcinomas of Unknown Primary

Primary tumor site determination for gastrointestinal (GI) tract and pancreaticobiliary (PB) tree carcinomas that present as metastasis of unknown primary can be problematic. Annexin A10 (ANXA10), claudin 18 (CLDN18), and trefoil factor 1 (TFF1) have been identified through expression profiling as markers of gastric lineage commitment; sex-determining region Y (SRY)-box transcription factor 2 (SOX2) expression has been reported in several tumor types, including gastric adenocarcinomas. We evaluated the diagnostic utility of immunohistochemistry for ANXA10, CLDN18, SOX2, and TFF1 for determining the site of origin for GI/PB adenocarcinomas. Immunohistochemistry for all 4 markers was performed on tissue microarrays including 559 GI/PB tumors and 421 other tumors. H-scores were calculated as the product of the intensity (0 to 3) and extent (percentage, 0% to 100%) of staining. Positive staining was defined as >5% staining. ANXA10 expression was most frequent in pancreatic adenocarcinomas when compared with all other GI/PB tumors (96.4% vs. 43.5%, P <0.001). Strong staining for ANXA10 (H-score ≥200) distinguished pancreatic ductal adenocarcinoma from intrahepatic cholangiocarcinoma and adenocarcinomas of the gallbladder and colorectum (69.6% vs. 0%, P <0.001). Triple positivity for ANXA10, CLDN18, and SOX2 was more frequent in esophagogastric tumors than in other GI/PB tumors (22.6% vs. 4.1%; P <0.001). TFF1 expression was observed in nearly all tumor types. Staining for ANXA10, CLDN18, and SOX2 as part of a panel may aid in distinguishing esophagogastric adenocarcinomas from lower GI/PB tumors. ANXA10 staining may be particularly useful in distinguishing pancreatic adenocarcinomas from intrahepatic cholangiocarcinoma and adenocarcinomas of the gallbladder and colorectum.

Trefoil factor 1 inhibits the development of esophageal adenocarcinoma from Barrett's epithelium

Trefoil factor family 1 (TFF1) is one of three members of the trefoil factor family that are abundantly expressed in the gastrointestinal mucosal epithelium. Recent studies have shown that TFF1 acts as a tumor suppressor in gastric, pancreatic and hepatocellular carcinogenesis; however, little is known about its function in esophageal carcinogenesis, especially in esophageal adenocarcinoma (EAC). Barrett's epithelium is the metaplastic columnar epithelium of the esophagus and a known premalignant lesion of EAC. To investigate the role of TFF1 in EAC development, a mouse model of Barrett's epithelium was employed, and human specimens of EAC were assessed by immunohistochemistry (IHC) and methylation-specific PCR. Wild-type (WT) mice underwent gastrojejunostomy on the forestomach, resulting in the development of Barrett's epithelium-like (BE-like) epithelium adjacent to the anastomotic site. BE-like epithelium in these mice expressed TFF1, indicating the association of TFF1 with esophageal adenocarcinoma. TFF1-knockout (TFF1KO) mice underwent the same procedure as well, revealing that a deficiency in TFF1 resulted in the development of adenocarcinoma in the anastomotic site, presumably from BE-like epithelium. IHC of human samples revealed strong TFF1 expression in Barrett's epithelium, which was lost in some EACs, confirming the association between TFF1 and EAC development. Aberrant DNA hypermethylation in TFF1 promoter lesions was detected in TFF1-negative human EAC samples, further confirming not only the role of TFF1 in EAC but also the underlying mechanisms of TFF1 regulation. In addition, IHC revealed the nuclear translocation of β-catenin in human and mouse EAC, suggesting that activation of the Wnt/β-catenin pathway was induced by the loss of TFF1. In conclusion, these results indicate that TFF1 functions as a tumor suppressor to inhibit the development of esophageal carcinogenesis from Barrett's epithelium.

Molecular Bases of Mechanisms Accounting for Drug Resistance in Gastric Adenocarcinoma

Gastric adenocarcinoma (GAC) is the most common histological type of gastric cancer, the fifth according to the frequency and the third among the deadliest cancers. GAC high mortality is due to a combination of factors, such as silent evolution, late clinical presentation, underlying genetic heterogeneity, and effective mechanisms of chemoresistance (MOCs) that make the available antitumor drugs scarcely useful. MOCs include reduced drug uptake (MOC-1a), enhanced drug efflux (MOC-1b), low proportion of active agents in tumor cells due to impaired pro-drug activation or active drug inactivation (MOC-2), changes in molecular targets sensitive to anticancer drugs (MOC-3), enhanced ability of cancer cells to repair drug-induced DNA damage (MOC-4), decreased function of pro-apoptotic factors versus up-regulation of anti-apoptotic genes (MOC-5), changes in tumor cell microenvironment altering the response to anticancer agents (MOC-6), and phenotypic transformations, including epithelial-mesenchymal transition (EMT) and the appearance of stemness characteristics (MOC-7). This review summarizes updated information regarding the molecular bases accounting for these mechanisms and their impact on the lack of clinical response to the pharmacological treatment currently used in GAC. This knowledge is required to identify novel biomarkers to predict treatment failure and druggable targets, and to develop sensitizing strategies to overcome drug refractoriness in GAC.

Drug resistance in cancer: mechanisms and tackling strategies

Drug resistance developed towards conventional therapy is one of the important reasons for chemotherapy failure in cancer. The various underlying mechanism for drug resistance development in tumor includes tumor heterogeneity, some cellular levels changes, genetic factors, and others novel mechanisms which have been highlighted in the past few years. In the present scenario, researchers have to focus on these novel mechanisms and their tackling strategies. The small molecules, peptides, and nanotherapeutics have emerged to overcome the drug resistance in cancer. The drug delivery systems with targeting moiety enhance the site-specificity, receptor-mediated endocytosis, and increase the drug concentration inside the cells, thus minimizing drug resistance and improve their therapeutic efficacy. These therapeutic approaches work by modulating the different pathways responsible for drug resistance. This review focuses on the different mechanisms of drug resistance and the recent advancements in therapeutic approaches to improve the sensitivity and effectiveness of chemotherapeutics.

TFF1 hypermethylation and decreased expression in esophageal squamous cell carcinoma and histologically normal tumor surrounding esophageal cells

Background

Esophageal squamous cell carcinoma (ESCC) is one of the 10 most incident cancer types in the world, and it is mainly associated with tobacco and alcohol consumption. ESCC mortality rates stand very close to its incidence, which is a direct consequence of a late diagnosis and an inefficient treatment. Although this scenery is quite alarming, the major molecular alterations that drive this carcinogenesis process remain unclear. We have previously shown through the first ESCC methylome analysis that TFF1 promoter is frequently hypermethylated in ESCC. Here, to evaluate TFF1 methylation as a potential biomarker of early ESCC diagnosis, we investigated the status of TFF1 promoter methylation and its expression in ESSC and histologically normal tumor surrounding tissue of ESCC patients in comparison to healthy esophagus of non-cancer individuals.

Results

Analysis of TFF1 promoter methylation, and gene and protein expression in 65 ESCC patients and 88 controls revealed that TFF1 methylation levels were already increased in histologically normal tumor surrounding tissue of ESCC patients when compared to healthy esophagus of non-cancer individuals. This increase in DNA methylation was followed by the reduction of TFF1 mRNA expression. Interestingly, TFF1 expression was capable of distinguishing tumor surrounding normal tissue from normal mucosa of healthy individuals with 92% accuracy. In addition, TFF1 protein was undetectable both in tumor and surrounding mucosa by immunohistochemistry, while submucosa glands of the healthy esophagus showed positive staining. Furthermore, treatment of TE-1 and TE-13 ESCC cell lines with decitabine led to a reduction of promoter methylation and consequent upregulation of TFF1 gene and protein expression. Finally, using TCGA data we showed that TFF1 loss is observed in ESCC, but not in esophageal adenocarcinoma, highlighting the different molecular mechanisms involved in the development of each histological subtype of esophageal cancer.

Conclusions

This study shows that TFF1 expression is silenced in early phases of ESCC development, which seems to be mediated at least in part by promoter hypermethylation, and provides the basis for the use of TFF1 expression as a potential biomarker for early ESCC detection.

Trefoil Factor Expression in a Human Model of the Early Stages of Barrett's Esophagus

BACKGROUND

Trefoil proteins are believed to have an important role in mucosal protection and repair in the gastrointestinal tract. They are well recognized in Barrett's esophagus and considered a potential biomarker for the condition. Metaplasia occurring in the esophageal remnant after esophagectomy is a human model for the early stages of development of Barrett's esophagus.

AIMS

To assess expression of trefoil proteins in post-esophagectomy columnar epithelium and to use trefoils as a molecular tool to understand regenerative mucosa in the esophagus.

METHODS

Patients with columnar metaplasia in the esophageal remnant were recruited from a large esophago-gastric cancer center. Trefoil factor expression was determined using immunohistochemical techniques.

RESULTS

Samples were obtained from 37 patients. TFF1 and TFF2 were expressed by all samples in a similar pattern to that described in studies of sporadic Barrett's esophagus. TFF3 was less widely expressed and was significantly associated with time elapsed between surgery and endoscopy. Median time from surgery to endoscopy was 8.1 years for patients with TFF3 expression versus 3.4 years for those without (p = 0.004).

CONCLUSIONS

Widespread expression of trefoils in this environment suggests that these proteins have an important role in development of Barrett's metaplasia. TFF3 expression may be absent in the early stages of metaplasia and may represent more established columnar epithelium. Biopsy samples from post-esophagectomy patients provide a valuable resource to study the early stages of Barrett's esophagus.

Pulsatile exposure to simulated reflux leads to changes in gene expression in a 3D model of oesophageal mucosa

Oesophageal exposure to duodenogastroesophageal refluxate is implicated in the development of Barrett's metaplasia (BM), with increased risk of progression to oesophageal adenocarcinoma. The literature proposes that reflux exposure activates NF-κB, driving the aberrant expression of intestine-specific caudal-related homeobox (CDX) genes. However, early events in the pathogenesis of BM from normal epithelium are poorly understood. To investigate this, our study subjected a 3D model of the normal human oesophageal mucosa to repeated, pulsatile exposure to specific bile components and examined changes in gene expression. Initial 2D experiments with a range of bile salts observed that taurochenodeoxycholate (TCDC) impacted upon NF-κB activation without causing cell death. Informed by this, the 3D oesophageal model was repeatedly exposed to TCDC in the presence and absence of acid, and the epithelial cells underwent gene expression profiling. We identified ~300 differentially expressed genes following each treatment, with a large and significant overlap between treatments. Enrichment analysis (Broad GSEA, DAVID and Metacore™; GeneGo Inc) identified multiple gene sets related to cell signalling, inflammation, proliferation, differentiation and cell adhesion. Specifically NF-κB activation, Wnt signalling, cell adhesion and targets for the transcription factors PTF1A and HNF4α were highlighted. Our data suggest that HNF4α isoform switching may be an early event in Barrett's pathogenesis. CDX1/2 targets were, however, not enriched, suggesting that although CDX1/2 activation reportedly plays a role in BM development, it may not be an initial event. Our findings highlight new areas for investigation in the earliest stages of BM pathogenesis of oesophageal diseases and new potential therapeutic targets.

Human carboxylesterase-2 hydrolyzes the prodrug of gemcitabine (LY2334737) and confers prodrug sensitivity to cancer cells

PURPOSE

The oral prodrug of gemcitabine LY2334737 is cleaved systemically to gemcitabine; the mechanism responsible for hydrolysis is unknown. LY2334737 cytotoxicity was tested in the NCI-60 panel; mining of microarray expression data identified carboxylesterase (CES) as a top hydrolase candidate. Studies examined whether CES is responsible for hydrolysis and whether cellular CES expression confers prodrug sensitivity.

EXPERIMENTAL DESIGN

Human recombinant CES isozymes were assayed for LY2334737 hydrolysis. Stable CES-overexpressing HCT-116 transfectants and a SK-OV-3 knockdown were prepared. Cell lines were tested for drug sensitivity and CES expression by quantitative real time-PCR (qRT-PCR), Western blotting, and immunohistochemical staining. Bystander cytotoxicity studies were conducted with GFP-tagged PC-3 cells as the reporter cell line. Therapeutic response of the HCT-116 transfectants was evaluated in xenografts.

RESULTS

Of 3 human CES isozymes tested, only CES2 hydrolyzed LY2334737. Five cell lines that express CES2 responded to LY2334737 treatment. LY2334737 was less cytotoxic to a SK-OV-3 CES2 knockdown than parental cells. The drug response of CES2-transfected HCT-116 cells correlated with CES2 expression level. Bystander studies showed statistically greater PC-3-GFP growth inhibition by LY2334737 when cells were cocultured with CES2 and not mock transfectants. Oral treatment of xenograft models with 3.2 mg/kg LY2334737 once a day for 21 days showed greater tumor growth inhibition of CES2 transfectant than the mock transfectant (P ≤ 0.001).

CONCLUSIONS

CES2 is responsible for the slow hydrolysis of LY2334737. Because intact prodrug circulates at high plasma levels after oral LY2334737 administration, improved response rates may be observed by tailoring LY2334737 treatment to patients with CES2 tumor expression.

Barrett's Esophagus: Emerging Knowledge and Management Strategies

The incidence of esophageal adenocarcinoma (EAC) has increased exponentially in the last 3 decades. Barrett's esophagus (BE) is the only known precursor of EAC. Patients with BE have a greater than 40 folds higher risk of EAC compared with the general population. Recent years have witnessed a revolution in the clinical and molecular research related to BE. However, several aspects of this condition remain controversial. Data regarding the true prevalence of BE have varied widely. Recent studies have suggested a lower incidence of EAC in nondysplastic BE (NDBE) than previously reported. There is paucity of prospective data showing a survival benefit of screening or surveillance for BE. Furthermore, the ever-increasing emphasis on healthcare cost containment has called for reexamination of the screening and surveillance strategies for BE. There is a need for identification of reliable clinical predictors or molecular biomarkers to risk-stratify patients who might benefit the most from screening or surveillance for BE. Finally, new therapies have emerged for the management of dysplastic BE. In this paper, we highlight the key areas of controversy and uncertainty surrounding BE. The paper discusses, in detail, the current literature about the molecular pathogenesis, biomarkers, histopathological diagnosis, and management strategies for BE.

Whole genome expression array profiling highlights differences in mucosal defense genes in Barrett's esophagus and esophageal adenocarcinoma

Esophageal adenocarcinoma (EAC) has become a major concern in Western countries due to rapid rises in incidence coupled with very poor survival rates. One of the key risk factors for the development of this cancer is the presence of Barrett's esophagus (BE), which is believed to form in response to repeated gastro-esophageal reflux. In this study we performed comparative, genome-wide expression profiling (using Illumina whole-genome Beadarrays) on total RNA extracted from esophageal biopsy tissues from individuals with EAC, BE (in the absence of EAC) and those with normal squamous epithelium. We combined these data with publically accessible raw data from three similar studies to investigate key gene and ontology differences between these three tissue states. The results support the deduction that BE is a tissue with enhanced glycoprotein synthesis machinery (DPP4, ATP2A3, AGR2) designed to provide strong mucosal defenses aimed at resisting gastro-esophageal reflux. EAC exhibits the enhanced extracellular matrix remodeling (collagens, IGFBP7, PLAU) effects expected in an aggressive form of cancer, as well as evidence of reduced expression of genes associated with mucosal (MUC6, CA2, TFF1) and xenobiotic (AKR1C2, AKR1B10) defenses. When our results are compared to previous whole-genome expression profiling studies keratin, mucin, annexin and trefoil factor gene groups are the most frequently represented differentially expressed gene families. Eleven genes identified here are also represented in at least 3 other profiling studies. We used these genes to discriminate between squamous epithelium, BE and EAC within the two largest cohorts using a support vector machine leave one out cross validation (LOOCV) analysis. While this method was satisfactory for discriminating squamous epithelium and BE, it demonstrates the need for more detailed investigations into profiling changes between BE and EAC.

Trefoil factor: implications for clinical laboratory diagnostics

Trefoil factors (TFF), expressed physiologically in the secretory cells of gastrointestinal mucosa and other mucosal tissues, compose a unique peptide family with important biologic functions. Aberrant expression and/or continued secretion of TFF might exist concurrently with the processes of digestive system inflammation, tumor or other related pathological changes. Previous pathological studies have shown that the abnormal expression of TFF is associated with the prognosis of digestive system diseases. The results obtained from gene expression profiling, tumor secretomics and bioinformatic analysis have positively confirmed that clinical detection of TFF peptides or mRNAs has an excellent diagnostic performance to detect digestive system diseases, especially for the monitoring of recurrence or metastasis of tumors and for the estimation of therapeutic efficacy and prognosis. Therefore, TFF is a potential biomarker for diagnosis, treatment and prognosis of digestive system diseases.

Differential gene expression in normal esophagus and Barrett's esophagus

PURPOSE

As the premalignant lesion of human esophageal adenocarcinoma (EAC), Barrett's esophagus (BE) is characterized by intestinal metaplasia in the normal esophagus (NE). Gene expression profiling with microarray and serial analysis of gene expression (SAGE) may help us understand the potential molecular mechanism of human BE.

METHODS

We analyzed three microarray datasets (two cDNA arrays and one oligonucleotide array) and one SAGE dataset with statistical tools, significance analysis of microarrays (SAM) and SAGE(Poisson), to identify individual genes differentially expressed in BE. Gene set enrichment analysis (GSEA) was used to identify a priori defined sets of genes that were differentially expressed. These gene sets were grouped according to either certain signaling pathways (GSEA curated), or the presence of consensus binding sequences of known transcription factors (GSEA motif). Immunohistochemical staining (IHC) was used to validate differential gene expression.

RESULTS

Both SAM and SAGE(Poisson) identified 68 differentially expressed genes (55 BE genes and 13 NE genes) with an arbitrary cutoff ratio (> or =4-fold). With IHC on matched pairs of NE and BE tissues from 6 patients, these genes were grouped into 6 categories: category I (25 genes only expressed in BE), category II (5 genes only expressed in NE), category III (8 genes expressed more in BE than in NE), and category IV (2 genes expressed more in NE than in BE). Differential expression of the remaining genes was not confirmed by IHC either due to false discovery (category V), or lack of proper antibodies (category VI). Besides individual genes, the TGFbeta pathway and several transcription factors (CDX2, HNF1, and HNF4) were identified by GSEA as enriched pathways and motifs in BE. Apart from 9 target genes known to be up-regulated in BE, IHC staining confirmed up-regulation of 19 additional CDX1 and CDX2 target genes in BE.

CONCLUSION

Our data suggested an important role of CDX1 and CDX2 in the development of BE. The IHC-confirmed gene list will lead to future studies on the molecular mechanism of BE.

Gene expression in Barrett's esophagus: laser capture versus whole tissue

OBJECTIVE

Diagnosis of Barrett's esophagus (BE) is typically done through morphologic analysis of esophageal tissue biopsy. Such samples contain several cell types. Laser capture microdissection (LCM) allows the isolation of specific cells from heterogeneous cell populations. The purpose of this study was to determine the degree of overlap of the two sample types and to define a set of genes that might serve as biochemical markers for BE.

MATERIAL AND METHODS

Biopsies were obtained from regions of the glandular tissue of BE and normal esophagus from 9 subjects with BE. Samples from 5 subjects were examined as whole tissue (BE [whole]; E [whole]), and in 4 subjects the glandular epithelium of BE was isolated using LCM (BE [LCM]) and compared with the averaged values (E [LCM]) for both basal cell (B [LCM]) and squamous cell (S [LCM]) epithelium.

RESULTS

Gene expression revealed 1797 probe sets between BE [whole] and E [whole] (fold change > 2.0; p<0.001). Most of these genes (74%) were also differentially expressed between BE [LCM] and E [LCM], showing that there was high concordance between the two sampling methods. LCM provided a great deal of additional information (2113 genes) about the alterations in gene expression that may represent the BE phenotype.

CONCLUSIONS

There are differences in gene expression profiles depending on whether specimens are whole tissue biopsies or LCM dissected. Whole tissue biopsies should prove satisfactory for diagnostic purposes. Because the data from LCM samples delineated many more Barrett's-specific genes, this procedure might provide more information regarding pathogenesis than would whole tissue material.

Expression analysis of Barrett's esophagus-associated high-grade dysplasia in laser capture microdissected archival tissue

PURPOSE

Identifying genes differentially expressed in nondysplastic BE (NDBE) from those expressed in high-grade dysplasia (HGD) should be of value in improving our understanding of this transition and may yield new diagnostic and/or prognostic markers. The aim of this study was to determine the differential transcriptome of HGD compared with NDBE through gene microarray analysis of epithelial cells microdissected from archival tissue specimens.

EXPERIMENTAL DESIGN

Laser capture microdissection was used to isolate epithelial cells from adjacent inflammatory and stromal cells. Epithelial mRNA was extracted from areas of NDBE and HGD in matched biopsies from 11 patients. mRNA was reverse transcribed and applied on Affymetrix cDNA microarray chips customized for formalin-exposed tissue. For a subset of these genes, differential gene expression was confirmed by real-time PCR and immunohistochemistry.

RESULTS

There were 131 genes overexpressed by at least 2.5-fold in HGD versus NDBE and 16 genes that were underexpressed by at least 2.5-fold. Among the overexpressed genes are several previously shown to be increased in the neoplastic progression of BE, as well as novel genes such as lipocalin-2, S100A9, matrix metallopeptidase 12, secernin 1, and topoisomerase IIalpha. Genes decreased in dysplastic epithelium include MUC5AC, trefoil factor 1 (TFF1), meprin A, and CD13. Real-time PCR validated the changes in expression in 24 of 28 selected genes. Immunohistochemistry confirmed increased protein expression for topoisomerase IIalpha, S100A9, and lipocalin-2 and decreased expression of TFF1 across the spectrum of BE-associated dysplasia from NDBE through adenocarcinoma.

CONCLUSIONS

This is the first study to identify epithelial genes differentially expressed in HGD versus NDBE in matched patient samples. The genes identified include several previously implicated in the pathogenesis of BE-associated dysplasia and new candidates for further investigation.

High throughput techniques for characterizing the expression profile of Barrett's esophagus

Barrett's esophagus (BE) is the metaplastic change of the normal lined squamous epithelium of the distal esophagus to a columnar type of epithelium as a result of chronic long-standing gastroesophageal reflux disease. Patients with BE have a significantly increased risk of developing an esophageal adenocarcinoma, with an estimated annual incidence varying from 0.4 to 1.8%. Over the last 3 decades, the incidence of BE and its associated adenocarcinoma has increased in Western countries at a rate that exceeds that of any other malignancy. Despite all the research performed on BE, there is still an inadequate understanding of the biological basis of this mucosal transformation. With the upcoming modern high throughput technologies, important progression has been made in unraveling the expression profiles and gaining more insight in the biology of BE and esophageal adenocarcinoma. Several studies reported genome, transcriptome, proteome, and kinome investigations using high throughput techniques. These studies were conducted to find biomarkers that can be used to detect BE patients with increased risk for malignant progression or to obtain more insight in the mechanism underlying BE development. In the following review, we first discuss the different techniques that are currently available and summarize findings in this field, including several recent publications of our group.

Gene expression profiling of esophageal cancer: Comparative analysis of Barrett's esophagus, adenocarcinoma, and squamous cell carcinoma

Esophageal cancer is a particularly aggressive tumor with poor prognosis, however, our current knowledge of the genes and pathways involved in tumorigenesis of the esophagus are limited. To obtain insight into the molecular processes underlying tumorigenesis of the esophagus, we have used cDNA microarrays to compare the gene expression profiles of 128 tissue samples representing the major histological subtypes of esophageal cancer (squamous cell carcinoma and adenocarcinoma (ADC)) as well as Barrett's esophagus (BE), the precursor lesion to ADC, and normal esophageal epithelium. Linear discriminant analysis and unsupervised hierarchical clustering show the separation of samples into 4 distinct groups consistent with their histological subtype. Differentially expressed genes were identified between each of the tissue types. Comparison of gene ontologies and gene expression profiles identified gene profiles specific to esophageal cancer, as well as BE. "Esophageal cancer clusters," representing proliferation, immune response, and extracellular matrix genes were identified, as well as digestion, hydrolase, and transcription factor clusters specific to the columnar phenotype observed during BE and esophageal ADC. These clusters provide valuable insight into the molecular and functional differences between normal esophageal epithelium, BE, and the 2 histologically distinct forms of esophageal cancers. Our thorough, unbiased analysis provides a rich source of data for further studies into the molecular basis of tumorigenesis of the esophagus, as well as identification of potential biomarkers for early detection of progression.

Localization of TFF3 peptide in human esophageal submucosal glands and gastric cardia: differentiation of two types of gastric pit cells along the rostro-caudal axis

TFF3 (trefoil factor family 3), which is a major secretory product of the gastric antrum and the intestine, but which is nearly absent in the gastric corpus, plays a key role in the maintenance of mucosal integrity. Here, we have systematically investigated TFF3 expression in the esophagus and gastric cardia by the use of reverse transcription/polymerase chain reaction (RT-PCR) analysis and immunohistochemistry. Synthesis of TFF3, but not TFF1 or TFF2, is detectable in esophageal submucosal glands. The stratified squamous epithelium is devoid of TFF synthesis. Prominent TFF3 expression starts at the Z-line with a sharply decreasing gradient toward the cardia. Immunohistochemistry has localized TFF3 to surface mucous cells of the proximal cardia. TFF3 distribution differs characteristically from that of TFF1 (secreted primarily by superficial surface mucous cells), whereas TFF3, together with the mucin MUC5AC, is also found in deeper lying cells toward the isthmus. This is the first report of TFF3 as a typical secretory peptide of esophageal submucosal glands and gastric cardia. The different expression patterns of TFF3 and TFF1 in the cardia suggest a stepwise maturation of surface mucous cells from TFF3/MUC5AC-positive cells close to the isthmus to TFF1/TFF3/MUC5AC-positive cells at the pit. The gradient of TFF3 expression along the gastric rostro-caudal axis defines two types of gastric pit cells: those secreting TFF3 in the cardia and the antrum and those nearly devoid of TFF3 synthesis in the corpus. This indicates the special requirement, particularly of the esophagogastric junction, for TFF3-triggered protection and repair.

Structure, function and regulation of carboxylesterases

This review covers current developments in molecular-based studies of the structure and function of carboxylesterases. To allay the confusion of the classic classification of carboxylesterase isozymes, we have proposed a novel nomenclature and classification of mammalian carboxylesterases on the basis of molecular properties. In addition, mechanisms of regulation of gene expression of carboxylesterases by xenobiotics and involvement of carboxylesterase in drug metabolism and enzyme induction are also described.