Bile acids induce cdx2 expression through the farnesoid x receptor in gastric epithelial cells

Gastric Adenocarcinomas with CDX2 Induction Show Higher Frequency of TP53 and KMT2B Mutations and MYC Amplifications but Similar Survival Compared with Cancers with No CDX2 Induction

Background: Gastric cancer is one of the most prevalent gastrointestinal cancers. Mortality is high, and improved treatments are needed. A better understanding of the pathophysiology of the disease and discovery of biomarkers for targeted therapies are paramount for therapeutic progress. CDX2, a transcription factor of hindgut specification, is induced in several gastric cancers, especially with intestinal differentiation, and could be helpful for defining sub-types with particular characteristics. Methods: Gastric cancers with induced CDX2 mRNA expression were identified from the gastric cohort of The Cancer Genome Atlas (TCGA) and were compared with cancers that had no CDX2 mRNA induction. Induced CDX2 mRNA expression was defined as mRNA expression z-score relative to all samples above 0, and non-induced CDX2 mRNA expression was defined as mRNA expression z-score relative to all samples below -1. Results: Patients with gastric cancers with CDX2 mRNA induction were older, had less frequently diffuse histology, and more often had mutations in TP53 and KMT2B and amplifications in MYC. CDX2 induction was correlated with HNF4α induction and was reversely correlated with SOX2. Gastric cancers with CDX2 mRNA induction showed lower PD-L1 expression than cancers with lower CDX2 expression but did not differ in CLDN18 mRNA expression. Progression-free and overall survival of the two groups was also not significantly different. Conclusion: Gastric cancers with CDX2 mRNA induction displayed specific characteristics that differentiate them from cancers with no CDX2 induction and could be of interest for optimizing current and future therapies.

Blastocyst-like Structures in the Peripheral Retina of Young Adult Beagles

In this immunohistological study on the peripheral retina of 3-year-old beagle dogs, excised retina specimens were immunostained with antibodies against nestin, Oct4, Nanog, Sox2, CDX2, cytokeratin 18 (CK 18), RPE65, and YAP1, as well as hematoxylin and DAPI, two nuclear stains. Our findings revealed solitary cysts of various sizes in the inner retina. Intriguingly, a mass of small round cells with scant cytoplasms was observed in the cavity of small cysts, while many disorganized cells partially occupied the cavity of the large cysts. The small cysts were strongly positive for nestin, Oct4, Nanog, Sox2, CDX2, CK18, and YAP1. RPE65-positive cells were exclusively observed in the tissue surrounding the cysts. Since RPE65 is a specific marker of retinal pigment epithelial (RPE) cells, the surrounding cells of the peripheral cysts were presumably derived from RPE cells that migrated intraretinally. In the small cysts, intense positive staining for nestin, a marker of retinal stem cells, seemed to indicate that they were derived from retinal stem cells. The morphology and positive staining for markers of blastocyst and RPE cells indicated that the small cysts may have formed structures resembling the blastocyst, possibly caused by the interaction between retinal stem cells and migrated RPE cells.

Gastric Intestinal Metaplasia: Real Culprit or Innocent Bystander as a Precancerous Condition for Gastric Cancer?

Gastric intestinal metaplasia (GIM), which denotes conversion of gastric mucosa into an intestinal phenotype, can occur in all regions of the stomach, including cardiac, fundic, and pyloric mucosa. Since the earliest description of GIM, its association with gastric cancer of the differentiated (intestinal) type has been a well-recognized concern. Many epidemiologic studies have confirmed GIM to be significantly associated with subsequent gastric cancer development. Helicobacter pylori, the principal etiologic factor for gastric cancer, plays the most important role in predisposing to GIM. Although the role of GIM in the stepwise progression model of gastric carcinogenesis (the so-called "Correa cascade") has come into question recently, we review the scientific evidence that strongly supports this long-standing model and propose a new progression model that builds on the Correa cascade. Eradication of H pylori is the most important method for preventing gastric cancer globally, but the effect of eradication on established GIM, is limited, if any. Endoscopic surveillance for GIM may, therefore, be necessary, especially when there is extensive corpus GIM. Recent advances in image-enhanced endoscopy with integrated artificial intelligence have facilitated the identification of GIM and neoplastic lesions, which will impact preventive strategies in the near future.

Huangqi Jianzhong Tang treats chronic atrophic gastritis rats by regulating intestinal flora and conjugated bile acid metabolism

Huangqi Jianzhong Tang (HQJZ) is effective for treating chronic atrophic gastritis (CAG). The present study was carried out to reveal the mechanism of HQJZ in CAG rats. The metabolism and microbial composition of the cecal contents in CAG rats were analyzed through the integration of an untargeted metabolomic approach using ultra-high-performance liquid chromatography coupled with the quadrupole-time of flight mass spectrometry (UHPLC-QTOF-MS) and 16S rRNA gene sequencing, respectively. Finally, MetOrigin analyses were performed to explore the relationship between differential metabolites and intestinal flora. The results showed that HQJZ could significantly regulate metabolic disorders, especially conjugated acid metabolites. 16S rRNA gene sequencing analysis illustrated that HQJZ decreased the abundance of Acetobacter, Desulfovibrio, Escherichia, and Shigella. MetOrigin metabolite traceability analysis showed that the six bile acids associated with HQJZ efficacy included three bacteria-host cometabolites, which were involved in the primary bile acid biosynthesis pathway. Research presented here confirmed that conjugated bile acid metabolism was key to the treatment of CAG by HQJZ and correlates strongly with Bacteroides acidifaciens and Prevotella copri. These findings provide new insights into the mechanisms to explain the efficacy of HQJZ.

Post-cholecystectomy bile reflux gastritis: Prevalence, risk factors, and clinical characteristics

OBJECTIVE

Bile reflux gastritis is caused by the backward flow of duodenal fluid into the stomach. A retrospective cohort study was performed to estimate the prevalence and risk factors of bile reflux gastritis postcholecystectomy, and to evaluate the endoscopic and histopathologic changes in gastric mucosa.

METHODS

Patients with refractory upper abdominal pain right below the ribs with symptoms of bloating, burping, nausea, vomiting, and bile regurgitation during the period from January 2018 to December 2020, submitted to Zagazig University Hospitals were enrolled in this study. The studied 64 patients were divided into two groups; the control group (CG): 30 subjects who had never undergone any biliary interventions, and the post-cholecystectomy group (PCG): 34 patients who had undergone cholecystectomy.

RESULTS

The prevalence of bile reflux gastritis was (16.7%) and (61.8%) in CG and PCG, respectively. Diabetes, obesity, elevated gastric bilirubin, and elevated stomach pH were all risk factors for bile reflux gastritis in both groups (r = .28,.48,.78,.57 respectively). Age, sex, epigastric pain, heartburn, vomiting, and the existence of bile reflux gastritis, on the other hand, had no correlation.

DISCUSSION

After a cholecystectomy, bile reflux gastritis is prevalent, especially among obese and diabetic patients.

The role of bile acid in intestinal metaplasia

A precancerous lesion of gastric cancer (GC), intestinal metaplasia (IM) is a pathological transformation of non-intestinal epithelium into an intestinal-like mucosa. It greatly raises the risk of developing the intestinal type of GC, which is frequently observed in the stomach and esophagus. It is understood that esophageal adenocarcinoma's precursor lesion, chronic gastroesophageal reflux disease (GERD), is what causes Barrett's esophagus (BE), an acquired condition. Recently, Bile acids (BAs), which are one of the compositions of gastric and duodenal contents, have been confirmed that it led to the occurrence and development of BE and gastric intestinal metaplasia (GIM). The objective of the current review is to discuss the mechanism of IM induced by bile acids. This review serves as a foundation for further research aimed at improving the way BE and GIM are currently managed.

The role of bile acids in carcinogenesis

Bile acids are soluble derivatives of cholesterol produced in the liver that subsequently undergo bacterial transformation yielding a diverse array of metabolites. The bulk of bile acid synthesis takes place in the liver yielding primary bile acids; however, other tissues have also the capacity to generate bile acids (e.g. ovaries). Hepatic bile acids are then transported to bile and are subsequently released into the intestines. In the large intestine, a fraction of primary bile acids is converted to secondary bile acids by gut bacteria. The majority of the intestinal bile acids undergo reuptake and return to the liver. A small fraction of secondary and primary bile acids remains in the circulation and exert receptor-mediated and pure chemical effects (e.g. acidic bile in oesophageal cancer) on cancer cells. In this review, we assess how changes to bile acid biosynthesis, bile acid flux and local bile acid concentration modulate the behavior of different cancers. Here, we present in-depth the involvement of bile acids in oesophageal, gastric, hepatocellular, pancreatic, colorectal, breast, prostate, ovarian cancer. Previous studies often used bile acids in supraphysiological concentration, sometimes in concentrations 1000 times higher than the highest reported tissue or serum concentrations likely eliciting unspecific effects, a practice that we advocate against in this review. Furthermore, we show that, although bile acids were classically considered as pro-carcinogenic agents (e.g. oesophageal cancer), the dogma that switch, as lower concentrations of bile acids that correspond to their serum or tissue reference concentration possess anticancer activity in a subset of cancers. Differences in the response of cancers to bile acids lie in the differential expression of bile acid receptors between cancers (e.g. FXR vs. TGR5). UDCA, a bile acid that is sold as a generic medication against cholestasis or biliary surge, and its conjugates were identified with almost purely anticancer features suggesting a possibility for drug repurposing. Taken together, bile acids were considered as tumor inducers or tumor promoter molecules; nevertheless, in certain cancers, like breast cancer, bile acids in their reference concentrations may act as tumor suppressors suggesting a Janus-faced nature of bile acids in carcinogenesis.

Roles and action mechanisms of bile acid-induced gastric intestinal metaplasia: a review

Gastric intestinal metaplasia (IM) is a precancerous lesion that increases the risk of subsequent gastric cancer (GC) development. Therefore, the mechanism of IM has been the focus of basic and clinical research. Helicobacter pylori (H. pylori) infection has been recognized as the main pathogenesis of gastric IM. However, more and more studies have shown that chronic inflammation of gastric mucosa caused by bile reflux is the key pathogenic factor of gastric IM. Bile reflux activates the expression of IM biomarkers via the bile acid receptor. In addition, microRNAs, exosomes, and epigenetics are also involved in the occurrence and development of bile acid-induced gastric IM. Currently, the relevant research is still very few. The molecular mechanism of the phenotypic transformation of gastrointestinal epithelial cells induced by bile acids has not been fully understood. This article mainly reviews the physiology and pathology of bile acid, mechanism of gastric IM induced by bile acid, bile acid receptors, and so on, in order to provide reference for further research.

Do obesity and diabetes increase the frequency and risk of bile reflux gastritis post-cholecystectomy?

<br><b>Introduction:</b> Biliary gastropathy is a disease characterized by upper abdominal pain, frequent heartburn, nausea, and vomiting of bile. It is caused by the backward flow of duodenal fluid into the stomach and esophagus.</br> <br><b>Aim:</b> A retrospective cohort study was performed to estimate the prevalence and risk factors of bile reflux gastritis secondary to cholecystectomy and to evaluate the endoscopic and histopathologic changes in gastric mucosa caused by bile reflux gastritis.</br> <br><b>Materials and methods:</b> The study involved 64 patients with epigastric pain and/or dyspeptic symptoms during the period from January 2018 to December 2020 who presented to Zagazig University Hospitals. The subjects were divided into two groups: the control group (CG), with 30 subjects who had never undergone any biliary interventions, and the post-cholecystectomy group (PCG), consisting of 34 patients who had undergone cholecystectomy.</br> <br><b>Results:</b> The prevalence of bile reflux gastritis was 16.7% in the CG and 61.8% in the PCG. In both groups, diabetes, obesity, increased gastric bilirubin, and increased gastric pH were risk factors for bile reflux gastritis (r = 0.28, 0.48, 0.78, and 0.57, respectively). However, there were no correlations between age, sex, epigastric pain, heartburn, vomiting, and the presence of bile reflux gastritis.</br> <br><b>Discussion:</b> Bile reflux gastritis is a common complication following cholecystectomy and is more common among obese and diabetic patients.</br>

Follistatin treatment modifies DNA methylation of the CDX2 gene in bovine preimplantation embryos

CDX2 plays a crucial role in the formation and maintenance of the trophectoderm epithelium in preimplantation embryos. Follistatin supplementation during the first 72 hr of in vitro culture triggers a significant increase in blastocyst rates, CDX2 expression, and trophectoderm cell numbers. However, the underlying epigenetic mechanisms by which follistatin upregulates CDX2 expression are not known. Here, we investigated whether stimulatory effects of follistatin are linked to alterations in DNA methylation within key regulatory regions of the CDX2 gene. In vitro-fertilized (IVF) zygotes were cultured with or without 10 ng/ml of recombinant human follistatin for 72 hr, then cultured without follistatin until Day 7. The bisulfite-sequencing analysis revealed differential methylation (DM) at specific CpG sites within the CDX2 promoter and intron 1 following follistatin treatment. These DM CpG sites include five hypomethylated sites at positions -1384, -1283, -297, -163, and -23, and four hypermethylated sites at positions -1501, -250, -243, and +20 in the promoter region. There were five hypomethylated sites at positions +3060, +3105, +3219, +3270, and +3545 in intron 1. Analysis of transcription factor binding sites using MatInspector combined with a literature search revealed a potential association between differentially methylated CpG sites and putative binding sites for key transcription factors involved in regulating CDX2 expression. The hypomethylated sites are putative binding sites for FXR, STAF, OCT1, KLF, AP2 family, and P53 protein, whereas the hypermethylated sites are putative binding sites for NRSF. Collectively, our results suggest that follistatin may increase CDX2 expression in early bovine embryos, at least in part, by modulating DNA methylation at key regulatory regions.

The role of transcription factor caudal-related homeobox transcription factor 2 in colorectal cancer

Colorectal cancer (CRC) is one of the most malignant tumors in humans and causes mass mortality. In the age of precise medicine, more and more subtypes of CRC were classified. The caudal-related homeobox transcription factor 2 (CDX2) is an intestine-specific transcription factor which is implicated in differentiation, proliferation, cell-adhesion, and migration. The loss of CDX2 in immunohistochemical stain was reported to be a prognostic factor of colon cancer, but the clinical application remained controversial. Most of the CRCs expressed or over-expressed CDX2. Homeobox genes can display either an oncogenic or a tumor-suppressing activity. CDX2 regulates the developing intestinal epithelium and CRC by different pathways. The complex regulation of CDX2 and its complex targets cause the difficulties of application for CDX2 in the prediction of prognosis. However, CDX2 is a potential biomarker applied in the precise classification of CRC for personalized medicine. This review partially clarifies the role of CDX2 in CRC.

Transcriptomic profiling reveals three molecular phenotypes of adenocarcinoma at the gastroesophageal junction

Cancers occurring at the gastroesophageal junction (GEJ) are classified as predominantly esophageal or gastric, which is often difficult to decipher. We hypothesized that the transcriptomic profile might reveal molecular subgroups which could help to define the tumor origin and behavior beyond anatomical location. The gene expression profiles of 107 treatment-naïve, intestinal type, gastroesophageal adenocarcinomas were assessed by the Illumina-HTv4.0 beadchip. Differential gene expression (limma), unsupervised subgroup assignment (mclust) and pathway analysis (gage) were undertaken in R statistical computing and results were related to demographic and clinical parameters. Unsupervised assignment of the gene expression profiles revealed three distinct molecular subgroups, which were not associated with anatomical location, tumor stage or grade (p > 0.05). Group 1 was enriched for pathways involved in cell turnover, Group 2 was enriched for metabolic processes and Group 3 for immune-response pathways. Patients in group 1 showed the worst overall survival (p = 0.019). Key genes for the three subtypes were confirmed by immunohistochemistry. The newly defined intrinsic subtypes were analyzed in four independent datasets of gastric and esophageal adenocarcinomas with transcriptomic data available (RNAseq data: OCCAMS cohort, n = 158; gene expression arrays: Belfast, n = 63; Singapore, n = 191; Asian Cancer Research Group, n = 300). The subgroups were represented in the independent cohorts and pooled analysis confirmed the prognostic effect of the new subtypes. In conclusion, adenocarcinomas at the GEJ comprise three distinct molecular phenotypes which do not reflect anatomical location but rather inform our understanding of the key pathways expressed.

Biliary Obstruction Promotes Multilineage Differentiation of Hepatic Stem Cells

Because of their high regenerative potential, stem cells are an ideal resource for development of therapies that replace injured tissue mass and restore function in patients with end-stage liver diseases. Using a rat model of bile duct ligation (BDL) and biliary fibrosis, we investigated cell engraftment, liver repopulation, and ectopic tissue formation after intrasplenic transplantation of epithelial stem/progenitor cells. Fetal liver cells were infused into the spleens of Fisher 344 rats with progressing biliary fibrosis induced by common BDL or rats without BDL. Cell delivery was well tolerated. After migration to the liver, donor-derived stem/progenitor cells engrafted, differentiated into hepatocytes and cholangiocytes, and formed large cell clusters at 2 months in BDL rats but not controls. Substantial numbers of donor cells were also detected at the splenic injection site where they generated hepatic and nonhepatic tissue. Transplanted cells differentiated into phenotypes other than hepato/cholangiocytic cells only in rats that underwent BDL. Quantitative reverse-transcription polymerase chain reaction analyses demonstrated marked up-regulation of tissue-specific genes of nonhepatic endodermal lineages (e.g., caudal type homeobox 2 [Cdx2], pancreatic and duodenal homeobox 1 [Pdx1], keratin 13 [CK-13]), confirmed by immunohistochemistry. Conclusion: BDL and its induced fibrosis promote liver repopulation by ectopically transplanted fetal liver-derived cells. These cell fractions contain multipotent stem cells that colonize the spleen of BDL rats and differentiate into multiple gastrointestinal tissues, including liver, pancreas, intestine, and esophagus. The splenic microenvironment, therefore, represents an ideal niche to assess the differentiation of these stem cells, while BDL provides a stimulus that induces their differentiation.

Farnesoid X receptor - a molecular predictor of weight loss after vertical sleeve gastrectomy?

OBJECTIVE

To determine the expression of the bile acid receptor, farnesoid X (FXR), in human gastric mucosa and investigate correlations between expression and body-mass index (BMI) and in patients with obesity, with changes in weight and BMI following vertical sleeve gastrectomy (VSG).

METHODS

Human gastric mucosa was obtained from normal/overweight individuals (macroscopically-normal tissue following surgery for malignancy) or from patients with obesity (VSG). The expression of FXR and its isoforms (FXRα, FXRβ) were examined by quantitative PCR and compared with the G protein-coupled bile acid receptor, GPBA. In patients with obesity, changes in BMI and weight loss were determined following VSG.

RESULTS

FXRα was the predominant isoform in normal/overweight individuals. FXR expression was higher in patients with obesity but GPBA receptor expression was unchanged. For those with obesity (n = 19), no correlation was found between FXR expression and change in Body-Mass Index (BMI)/month or weight loss/month, taken 3 ± 1 months after surgery, or in BMI or weight at surgery.

CONCLUSIONS

Obesity is associated with increased FXR expression in the gastric mucosa. The findings are preliminary but suggest that this increase in FXR expression is a consequence of obesity, rather than its cause.

Bile acids promote gastric intestinal metaplasia by upregulating CDX2 and MUC2 expression via the FXR/NF-κB signalling pathway

Bile acids serve a critical role in the induction of gastric intestinal metaplasia (IM) and gastric carcinogenesis. The present study investigated the effects of bile acids on the induction of gastric IM formation. The results demonstrated that the expression levels of caudal-related homeobox transcription factor 2 (CDX2), mucin 2 (MUC2) and farnesoid X receptor (FXR) were increased in vitro and in vivo following treatment with bile acids, and CDX2 transcriptionally activated MUC2 expression. Furthermore, knockdown of FXR attenuated bile acid-enhanced CDX2 promoter activity and protein expression. Conversely, the FXR agonist GW4064 synergistically enhanced bile acid-induced CDX2 promoter activity. Bile acid treatment led to an increase in nuclear factor (NF)-κB activity and protein expression. Treatment with GW4064 or the FXR antagonist Z-guggulsterone enhanced or attenuated bile acid-induced NF-κB activity, respectively. In addition, quantitative chromatin immunoprecipitation confirmed that bile acids led to enhanced binding of p50 to the CDX2 promoter, whereas this effect was not observed for p65. Treatment with GW4064 or Z-guggulsterone enhanced and attenuated the binding activity of p50 to the CDX2 promoter, respectively. These results indicated that bile acids may activate the FXR/NF-κB signalling pathway, thereby upregulating CDX2 and MUC2 expression in normal gastric epithelial cells.

Etiology, pathogenesis, diagnosis and treatment of bile reflux gastritis

Bile reflux gastritis is a common disease of the digestive system, whose clinical characteristics are abdominal pain, abdominal distention and nausea and vomiting, affecting the quality of life of patients seriously. However, the etiology and pathogenesis of bile reflux gastritis are still unclear, which may be related to gastrointestinal surgery, gallbladder disease, Helicobacter pylori infection, psychological factors, etc. There are many diagnostic methods, but a consensus on diagnosis is still lacking. Most of the current treatments are symptomatic treatments, but the overall efficacy is poor. This article reviews the etiology, pathogenesis, diagnosis and treatment of bile reflux gastritis, with an aim to provide a reference for further research of this disease.

Guts and Gall: Bile Acids in Regulation of Intestinal Epithelial Function in Health and Disease

Epithelial cells line the entire surface of the gastrointestinal tract and its accessory organs where they primarily function in transporting digestive enzymes, nutrients, electrolytes, and fluid to and from the luminal contents. At the same time, epithelial cells are responsible for forming a physical and biochemical barrier that prevents the entry into the body of harmful agents, such as bacteria and their toxins. Dysregulation of epithelial transport and barrier function is associated with the pathogenesis of a number of conditions throughout the intestine, such as inflammatory bowel disease, chronic diarrhea, pancreatitis, reflux esophagitis, and cancer. Driven by discovery of specific receptors on intestinal epithelial cells, new insights into mechanisms that control their synthesis and enterohepatic circulation, and a growing appreciation of their roles as bioactive bacterial metabolites, bile acids are currently receiving a great deal of interest as critical regulators of epithelial function in health and disease. This review aims to summarize recent advances in this field and to highlight how bile acids are now emerging as exciting new targets for disease intervention.

Googling the Guggul (Commiphora and Boswellia) for Prevention of Chronic Diseases

Extensive research during last 2 decades has revealed that most drugs discovered today, although costs billions of dollars for discovery, and yet they are highly ineffective in their clinical response. For instance, the European Medicines Agency has approved 68 anti-cancer drugs, and out of which 39 has reached the market level with no indication of increased survival nor betterment of quality of life. Even when drugs did improve survival rate compared to available treatment strategies, most of these were found to be clinically insignificant. This is a fundamental problem with modern drug discovery which is based on thinking that most chronic diseases are caused by alteration of a single gene and thus most therapies are single gene-targeted therapies. However, extensive research has revealed that most chronic diseases are caused by multiple gene products. Although most drugs designed by man are mono-targeted therapies, however, those designed by "mother nature" and have been used for thousands of years, are "multi-targeted" therapies. In this review, we examine two agents that have been around for thousands of years, namely "guggul" from Commiphora and Boswellia. Although we are all familiar with the search engine "google," this is another type of "guggul" that has been used for centuries and being explored for its various biological activities. The current review summarizes the traditional uses, chemistry, in vitro and in vivo biological activities, molecular targets, and clinical trials performed with these agents.

Activation of FXR promotes intestinal metaplasia of gastric cells via SHP-dependent upregulation of the expression of CDX2

Gastric intestinal metaplasia (IM) induced by bile acid is a precancerous lesion of gastric adenocarcinoma and is associated with the expression of caudal-related homeobox 2 (CDX2). In the present study, the role of farnesoid X receptor (FXR) on the regulation of CDX2 in gastric cells was investigated and the underlying molecular mechanisms were examined. Human gastric cell lines were treated with chenodeoxycholic acid (CDCA) or FXR agonist GW4064. Cells were treated with CDCA in the presence or absence of the FXR antagonist or FXR siRNA transfection. Next, cells were treated with CDCA in the presence or absence of SHP siRNA transfection and FXR, CDX2 and SHP mRNA and protein levels were determined by reverse transcription-quantitative polymerase chain reaction and western blot analysis. A chromatin immunoprecipitation assay was performed to examine the relationship between FXR and SHP and the expressions of FXR and CDX2 in gastritis and IM tissues were detected using immunohistochemistry. The results revealed that CDCA was able to induce CDX2 expression, which could be blocked by inhibition or knockdown of FXR. Mechanistically, FXR directly induced the expression of small heterodimer partner (SHP). SHP knockdown significantly decreased CDCA-induced CDX2 expression. ChIP results indicated that FXR could directly bind SHP promoter and promote SHP expression. Finally, immunohistochemistry results demonstrated that the expression levels of CDX2 and FXR in human IM lesions were significantly higher, compared with those in gastritis lesions, and were positively correlated. Collectively, these results revealed that the activation of FXR and sequential direct transcriptional induction of SHP were involved in the expression of CDX2 induced by bile acid in gastric IM lesions.

Clinical significance of farnesoid X receptor expression in thyroid neoplasia

Aim: To evaluate the clinical significance of farnesoid X receptor (FXR) in thyroid neoplasia. Patients & methods: FXR expression was assessed immunohistochemically on 88 thyroid neoplastic tissues (benign = 44, malignant = 44). Results: Enhanced FXR was more frequently observed in papillary carcinomas compared with hyperplastic nodules (p = 0.0489). In malignant lesions, elevated FXR was associated with capsular (p = 0.0004) and vascular invasion (p = 0.0056) and increased follicular cells’ proliferative rate (p < 0.0001). Elevated FXR expression was also associated with larger tumor size (p = 0.0086), presence of lymph node metastases (p = 0.0239) and lymphatic invasion (p = 0.0086) and increased recurrence rate risk (p = 0.0239). Conclusion: FXR may be associated with tumor aggressiveness that affects patients’ survival in thyroid neoplasia.

Deoxycholic Acid Could Induce Apoptosis and Trigger Gastric Carcinogenesis on Gastric Epithelial Cells by Quantitative Proteomic Analysis

Background. Pathologic duodenogastric reflux can induce or aggravate gastritis because of the presence of bile acids. Bile reflux has been generally considered to be associated with intestinal metaplasia and gastric cancer. However, the pathogenic mechanisms of the effects of bile acids on gastric mucosa are still unknown. Methods. To explore the mechanisms by which bile acids induce gastric mucosal lesions, we examined cell apoptosis in the gastric epithelial cell line GES-1 and investigated the changes in protein profiles of GES-1 cells in response to a bile acid deoxycholic acid using a proteomics approach. Changes in the profiles of the differently expressed proteins were analyzed using the DAVID and STRING programs. Results. We found apoptosis was significantly induced in GES-1 cells by deoxycholic acid. Using liquid chromatographic/tandem mass spectrometric (LC-MS/MS) methods, 134 upregulated proteins and 214 downregulated proteins were identified in the bile acid treated GES-1 cells. Bioinformatics analysis revealed the interactions and signaling networks of these differentially expressed proteins. Conclusion. These findings may improve the understanding of the molecular mechanisms underlying the pathogenicity of bile acids on gastric mucosa.

Guggulsterone and Its Role in Chronic Diseases

Guggulsterone is a plant sterol derived from gum resin of Commiphora wightii. The gum resin from guggul plants has been used for thousand years in Ayurveda to treat various disorders, including internal tumors, obesity, liver disorders, malignant sores and ulcers, urinary complaints, intestinal worms, leucoderma, sinuses, edema, and sudden paralytic seizures. Guggulsterone has been identified a bioactive components of this gum resin. This plant steroid has been reported to work as an antagonist of certain nuclear receptors, especially farnesoid X receptor, which regulates bile acids and cholesterol metabolism. Guggulsterone also mediates gene expression through the regulation of transcription factors, including nuclear factor-kappa B and signal transducer and activator of transcription 3, which plays important roles in the development of inflammation and tumorigenesis. Guggulsterone has been shown to downregulate the expression of proteins involved in anti-apoptotic, cell survival, cell proliferation, angiogenic, metastatic, and chemoresistant activities in tumor cells. This review aimed to clarify the cell signal pathways targeted by guggulsterone and the bioactivities of guggulsterone in animal models and humans.

Farnesoid X receptor signal is involved in deoxycholic acid-induced intestinal metaplasia of normal human gastric epithelial cells

The farnesoid X receptor (FXR) signaling pathway is known to be involved in the metabolism of bile acid, glucose and lipid. In the present study, we demonstrated that 400 µmol/l deoxycholic acid (DCA) stimulation promotes the proliferation of normal human gastric epithelial cells (GES-1). In addition, DCA activated FXR and increased the expression of intestinal metaplasia genes, including caudal-related homeobox transcription factor 2 (Cdx2) and mucin 2 (MUC2). The treatment of FXR agonist GW4064/antagonist guggulsterone (Gug.) significantly increased/decreased the expression levels of FXR, Cdx2 and MUC2 protein in DCA-induced GES-1 cells. GW4064/Gug. also enhanced/reduced the nuclear factor-κB (NF-κB) activity and binding of the Cdx2 promoter region and NF-κB, the most common subunit p50 protein. Taken together, the results indicated that DCA is capable of modulating the expression of Cdx2 and the downstream MUC2 via the nuclear receptor FXR-NF-κB activity in normal gastric epithelial cells. FXR signaling pathway may therefore be involved in the intestinal metaplasia of human gastric mucosa.

Nuclear bile acid signaling through the farnesoid X receptor

Bile acids (BAs) are amphipathic molecules produced from cholesterol by the liver. Expelled from the gallbladder upon meal ingestion, BAs serve as fat solubilizers in the intestine. BAs are reabsorbed in the ileum and return via the portal vein to the liver where, together with nutrients, they provide signals to coordinate metabolic responses. BAs act on energy and metabolic homeostasis through the activation of membrane and nuclear receptors, among which the nuclear receptor farnesoid X receptor (FXR) is an important regulator of several metabolic pathways. Highly expressed in the liver and the small intestine, FXR contributes to BA effects on metabolism, inflammation and cell cycle control. The pharmacological modulation of its activity has emerged as a potential therapeutic strategy for liver and metabolic diseases. This review highlights recent advances regarding the mechanisms by which the BA sensor FXR contributes to global signaling effects of BAs, and how FXR activity may be regulated by nutrient-sensitive signaling pathways.

Emerging potential of natural products for targeting mucins for therapy against inflammation and cancer

Deregulated mucin expression is a hallmark of several inflammatory and malignant pathologies. Emerging evidence suggests that, apart from biomarkers, these deregulated mucins are functional contributors to the pathogenesis in inflammation and cancer. Both overexpression and downregulation of mucins in various organ systems is associated with pathobiology of inflammation and cancer. Restoration of mucin homeostasis has become an important goal for therapy and management of such disorders has fueled the quest for selective mucomodulators. With improved understanding of mucin regulation and mechanistic insights into their pathobiological roles, there is optimism to find selective non-toxic agents capable of modulating mucin expression and function. Recently, natural compounds derived from dietary sources have drawn attention due to their anti-inflammatory and anti-oxidant properties and low toxicity. Considerable efforts have been directed towards evaluating dietary natural products as chemopreventive and therapeutic agents; identification, characterization and synthesis of their active compounds; and improving their delivery and bioavailability. We describe the current understanding of mucin regulation, rationale for targeting mucins with natural products and discuss some natural products that modulate mucin expression and functions. We further discuss the approaches and parameters that should guide future research to identify and evaluate selective natural mucomodulators for therapy.

Transformation of intestinal stem cells into gastric stem cells on loss of transcription factor Cdx2

The endodermal lining of the adult gastro-intestinal tract harbours stem cells that are responsible for the day-to-day regeneration of the epithelium. Stem cells residing in the pyloric glands of the stomach and in the small intestinal crypts differ in their differentiation programme and in the gene repertoire that they express. Both types of stem cells have been shown to grow from single cells into 3D structures (organoids) in vitro. We show that single adult Lgr5-positive stem cells, isolated from small intestinal organoids, require Cdx2 to maintain their intestinal identity and are converted cell-autonomously into pyloric stem cells in the absence of this transcription factor. Clonal descendants of Cdx2^null small intestinal stem cells enter the gastric differentiation program instead of producing intestinal derivatives. We show that the intestinal genetic programme is critically dependent on the single transcription factor encoding gene Cdx2.

The adult gastro-intestinal tract harbours stem cells that differ in their differentiation programme and in the gene repertoire that they express. Here the authors show that single adult Lgr5-positive stem cells require Cdx2 to maintain their intestinal identity and are converted into pyloric stem cells in the absence of this transcription factor.

Guggulsterone, a plant-derived inhibitor of NF-TB, suppresses CDX2 and COX-2 expression and reduces the viability of esophageal adenocarcinoma cells

BACKGROUND/AIMS

Induction by bile acid of caudal type homeobox 2 (CDX2) and cyclooxygenase-2 (COX-2) expression via nuclear factor-κB (NF-κB) activation is a critical event in the development of Barrett's esophagus (BE) and esophageal adenocarcinoma (EAC). Guggulsterone (GS) is a plant sterol that inhibits NF-κB activity. Here, we evaluated whether GS has either or both chemopreventive or therapeutic effects against EAC.

METHODS

Two EAC cells lines were treated with deoxycholic acid (DCA) in the presence of GS or vehicle. The levels of transcription and translation of IκBα, CDX2, and COX-2 were determined. Prostaglandin E2 (PGE2) levels, cell viability, and cell cycle distribution were assessed as well.

RESULTS

GS inhibited DCA-induced IκBα phosphorylation. GS and the NF-κB inhibitor BAY11-7085 suppressed DCA-induced CDX2 and COX-2 expression in EAC cells. GS also suppressed basal transcription levels of CDX2 and COX-2 and reduced constitutive synthesis of COX-2 and PGE2. Further, GS reduced the viability of EAC cells, increased their numbers in the apoptotic sub-G1 fraction.

CONCLUSION

GS suppressed DCA-induced and NF-κB-dependent activation of CDX2 and COX-2 expression. Further, GS also reduced the viability of EAC cells. GS may serve as candidate for preventing and treating EAC and BE.

Changes in gastric mucosa of rats with experimental bile reflux gastritis: Interventional effects of Liangjun Oral Liquid

AIM: To observe the pathologic changes and the expression of cyclooxygenase-2 (COX-2) in gastric mucosa of rats with experimental bile reflux gastritis (BRG) and to assess the interventional effects of Liangjun Oral Liquid.

METHODS: Forty rats were divided into four groups: Ⅰ (BRG model), Ⅱ (BRG model treated with Liangjun Oral Liquid 1 mL/kg), Ⅲ (normal rats treated with Liangjun Oral Liquid 1 mL/kg) and Ⅳ (normal controls). BRG was induced using self-made reflux liquid. The changes in the gastric mucosa of rats in each group were observed by optical microscopy and transmission electron microscopy (TEM). The expression of COX-2 protein was evaluated by immunohistochemistry (IHC).

RESULTS: In group Ⅰ, 60% of rats had severe inflammation in the gastric mucosa, 20% had mild atypical hyperplasia, 20% had intestinal metaplasia; 70% had strong COX-2 protein expression. Compared with group Ⅰ, the pathological changes were improved and the expression of COX-2 was decreased (P < 0.05) in group Ⅱ: 20% of rats had severe inflammation in the gastric mucosa, 5% had mild atypical hyperplasia, 5% had intestinal metaplasia; 10% had strong COX-2 protein expression. No pathologic changes were found in the gastric mucosa of rats in groups Ⅲ and Ⅳ, and the expression of COX-2 protein was almost undetectable and there were no significant differences between the two groups.

CONCLUSION: Liangjun Oral Liquid can relieve the gastric mucosal injury in rats with experimental bile reflux gastritis by decreasing the expression of COX-2.

A pSMAD/CDX2 complex is essential for the intestinalization of epithelial metaplasia

The molecular mechanisms leading to epithelial metaplasias are poorly understood. Barrett's esophagus is a premalignant metaplastic change of the esophageal epithelium into columnar epithelium, occurring in patients suffering from gastroesophageal reflux disease. Mechanisms behind the development of the intestinal subtype, which is associated with the highest cancer risk, are unclear. In humans, it has been suggested that a nonspecialized columnar metaplasia precedes the development of intestinal metaplasia. Here, we propose that a complex made up of at least two factors needs to be activated simultaneously to drive the expression of intestinal type of genes. Using unique animal models and robust in vitro assays, we show that the nonspecialized columnar metaplasia is a precursor of intestinal metaplasia and that pSMAD/CDX2 interaction is essential for the switch toward an intestinal phenotype.

Nuclear receptors as drug targets in cholestatic liver diseases

Cholestatic liver diseases encompass a wide spectrum of disorders with different causes, resulting in impaired bile flow and accumulation of bile acids and other potentially hepatotoxic cholephils. The understanding of the molecular mechanisms of bile formation and cholestasis has recently improved significantly through new insights into nuclear receptor (patho)biology. Nuclear receptors are ligand-activated transcription factors, which act as central players in the regulation of genes responsible for elimination and detoxification of biliary constituents accumulating in cholestasis. They also control other pathophysiologic processes such as inflammation, fibrogenesis, and carcinogenesis involved in the pathogenesis and disease progression of cholestasis liver diseases.

Bile acid promotes intestinal metaplasia and gastric carcinogenesis

BACKGROUND

Bile acid and Helicobacter pylori (H. pylori) are important toxic factors for gastric mucosal injury. We examined the role of bile acid in promoting histologic gastritis and gastric carcinoma in Japanese patients.

METHODS

A total of 767 patients (452 men, mean age 51.1 years) were studied. Gastric juice was collected by gastro-endoscopic examination, and the bile acid concentration was examined by enzymatic method. The grade of histologic gastritis was evaluated by gastric biopsies, and the relationship between the bile acid concentration and the gastritis score was examined. The occurrence of gastric cancer was examined by a retrospective cohort study. CDX2/CINC1 expression in RGM-1 cells was evaluated by real-time PCR.

RESULTS

In H. pylori-positive patients, we found significant positive correlation between the bile acid concentration and the grades of atrophy/intestinal metaplasia (P < 0.01). However, we found significant negative associations between the bile acid concentrations and the histologic scores of mononuclear cell/neutrophil infiltrations (P < 0.01). Patients with a high concentration of bile acid developed gastric cancer more frequently than those with a low concentration (P < 0.05). Cholic acid treatment significantly increased CDX2 expression in RGM-1 cells. CINC1 expression in RGM-1 cell was significantly induced by coculture with H. pylori, and the induction was reduced by glycochenodeoxycholic acid treatment.

CONCLUSION

The bile acid in gastric juice contributes to the progression of histologic atrophy and intestinal metaplasia without inflammatory cell infiltration, followed by carcinogenesis in H. pylori-positive patients.

IMPACT

Bile acid promotes intestinal metaplasia and gastric carcinogenesis without inflammatory cell infiltration.

Anti-inflammatory and metabolic actions of FXR: insights into molecular mechanisms

The farnesoid X receptor (FXR) is a ligand-activated transcription factor belonging to the nuclear receptor (NR) superfamily. FXR plays an important role in positively regulating genes (transactivation) involved in bile acid homeostasis, fat and glucose metabolism. Recently, it has become clear that an additional important role for FXR consists of downregulating genes involved in inflammation. Because of this broad spectrum of regulated genes, therapeutically targeting FXR with full agonists will likely result in adverse side effects, in line with what is described for other NRs. It may therefore be necessary to develop selective FXR modulators. However, the molecular mechanisms that distinguish between FXR-mediated transactivation and transrepression are currently unknown. For other NRs, post-translational modifications such as SUMOylation and phosphorylation have been reported to be unique to either transactivation or transrepression. Here, we review current knowledge on post-translational regulation of FXR with respect to transactivation and transrepression. Ultimately, increased understanding of the different mechanisms of transactivation and transrepression of nuclear receptors will aid in the development of NR drugs with fewer side effects.

The Role of CDX2 in Intestinal Metaplasia Evaluated Using Immunohistochemistry

Background/Aims

Intestinal metaplasia (IM) has been regarded as a premalignant condition. This study evaluated the role of the transforming factor CDX2 according to the severity and type of IM.

Methods

This analysis was performed on 383 subjects with IM in the antrum and/or body, with diagnoses that were categorized as controls, dysplasias, and gastric cancers. The IM grades were classified into four groups as negative, mild, moderate or severe using the updated Sydney scoring system. The IM subtypes were categorized as type I, type II, and type III using high iron diamine and alcian blue (pH 2.5) staining. The CDX2 expression in the IM foci was evaluated using immunohistochemistry in specimens from the antrum and/or body.

Results

CDX2 expression increased according to IM severity (p=0.001) but was not associated with the IM subtype (p=0.881) in the antrum specimens. Similarly, CDX2 expression increased according to the IM grade (p=0.001) but was not associated with the IM subtype (p=0.755) in the body specimens. CDX2 expression was also increased according to baseline disease in the antrum, especially dysplastic and GC group (p=0.003), but not in the body (p=0.582). However, status of Helicobacter pylori infection was not associated with CDX2 expression in the antrum (p=0.692) and body (p=0.271).

Conclusions

These results show that CDX2 expression is associated with the IM grade regardless of the IM subtype and that it was more frequent in the dysplasia group. These results suggest that CDX2 expression might play an important role in the progression of IM in various environments that can affect neoplastic change.

Relation between reflux of bile acids into the stomach and gastric mucosal atrophy, intestinal metaplasia in biopsy specimens

During endoscopic examinations we collected fluid in the stomach that included reflux fluid from the duodenum, and assessed the effect of quantitatively determined bile acids on glandular atrophy and intestinal metaplasia using biopsy specimens. A total of 294 outpatients were enrolled in this study. Total bile acid concentration was measured by an enzyme immunoassay. Glandular atrophy and intestinal metaplasia scores were graded according to the Updated Sydney System. An effect of refluxed bile acids on atrophy and intestinal metaplasia was shown in the high-concentration reflux group in comparison with the control group. However, when the odds ratios (ORs) were calculated according to whether Helicobacter pylori (H. pylori) infection was present, no significant associations were shown between reflux bile acids and atrophy in either the H. pylori-positive cases or -negative cases. The same was true for intestinal metaplasia in the H. pylori-positive cases, whereas intestinal metaplasia was more pronounced in the high-concentration reflux group in the H. pylori-negative cases (OR 2.4, 95%CI 1.1–5.6). We could not clarify the effect of the reflux of bile acids into the stomach in the progression of atrophy. High-concentration bile acids had an effect on the progression of intestinal metaplasia in the H. pylori-negative cases.

Farnesoid X receptor protects human and murine gastric epithelial cells against inflammation-induced damage

Bile acids from duodenogastric reflux promote inflammation and increase the risk for gastro-oesophageal cancers. FXR (farnesoid X receptor/NR1H4) is a transcription factor regulated by bile acids such as CDCA (chenodeoxycholic acid). FXR protects the liver and the intestinal tract against bile acid overload; however, a functional role for FXR in the stomach has not been described. We detected FXR expression in the normal human stomach and in GC (gastric cancer). FXR mRNA and protein were also present in the human GC cell lines MKN45 and SNU5, but not in the AGS cell line. Transfection of FXR into AGS cells protected against TNFα (tumour necrosis factor α)-induced cell damage. We identified K13 (keratin 13), an anti-apoptotic protein of desmosomes, as a novel CDCA-regulated FXR-target gene. FXR bound to a conserved regulatory element in the proximal human K13 promoter. Gastric expression of K13 mRNA was increased in an FXR-dependent manner by a chow diet enriched with 1% (w/w) CDCA and by indomethacin (35 mg/kg of body weight intraperitoneal) in C57BL/6 mice. FXR-deficient mice were more susceptible to indomethacin-induced gastric ulceration than their WT (wild-type) littermates. These results suggest that FXR increases the resistance of human and murine gastric epithelial cells to inflammation-mediated damage and may thus participate in the development of GC.

Rebamipide, a mucoprotective drug, inhibits NSAIDs-induced gastric mucosal injury: possible involvement of the downregulation of 15-hydroxyprostaglandin dehydrogenase

Prostaglandin E₂ plays an important role in the maintenance of gastric mucosal integrity. The level of biologically active prostaglandin E₂ in the tissue is regulated by the balanced expression of its synthetic enzymes, such as cyclooxygenase, and its catabolic enzyme, 15-hydroxyprostaglandin dehydrogenase. We examined the effect of rebamipide, a mucoprotective drug, on prostaglandin E₂ production and metabolism in the gastric tissue and its effect on indomethacin-induced gastric mucosal injury in mice. Rebamipide suppressed indomethacin-induced gastric mucosal injury. Suppressive effect of rebamipide on indomethacin-induced gastric mucosal injury was also observed in cyclooxygenase-2-knockout mice. The mice that were treated with rebamipide showed a 2-fold increase in cyclooxygenase-2 mRNA expression in the gastric tissue, whereas 15-hydroxyprostaglandin dehydrogenase mRNA expression markedly decreased as compared to vehicle-treated control mice. Rebamipide did not affect the expression of cyclooxygenase-1 in the gastric tissue. Rebamipide did not increase prostaglandin E₂ production in the gastric tissue; however, it induced a 1.4-fold increase in the concentration of prostaglandin E₂ in the gastric tissue as compared to vehicle-treated control mice. These results suggest that the suppressive effect of rebamipide on non-steroidal anti-inflammatory drugs-induced gastric mucosal injury can be attributed to reduced 15-hydroxyprostaglandin dehydrogenase expression, which increases the prostaglandin E₂ concentration in the gastric tissue.