Dataset Information

In Barrett's esophagus patients and Barrett's cell lines, ursodeoxycholic acid increases antioxidant expression and prevents DNA damage by bile acids.

ABSTRACT: Hydrophobic bile acids like deoxycholic acid (DCA), which cause oxidative DNA damage and activate NF-?B in Barrett's metaplasia, might contribute to carcinogenesis in Barrett's esophagus. We have explored mechanisms whereby ursodeoxycholic acid (UDCA, a hydrophilic bile acid) protects against DCA-induced injury in vivo in patients and in vitro using nonneoplastic, telomerase-immortalized Barrett's cell lines. We took biopsies of Barrett's esophagus from 21 patients before and after esophageal perfusion with DCA (250 ?M) at baseline and after 8 wk of oral UDCA treatment. DNA damage was assessed by phospho-H2AX expression, neutral CometAssay, and phospho-H2AX nuclear foci formation. Quantitative PCR was performed for antioxidants including catalase and GPX1. Nrf2, catalase, and GPX1 were knocked down with siRNAs. Reporter assays were performed using a plasmid construct containing antioxidant responsive element. In patients, baseline esophageal perfusion with DCA significantly increased phospho-H2AX and phospho-p65 in Barrett's metaplasia. Oral UDCA increased GPX1 and catalase levels in Barrett's metaplasia and prevented DCA perfusion from inducing DNA damage and NF-?B activation. In cells, DCA-induced DNA damage and NF-?B activation was prevented by 24-h pretreatment with UDCA, but not by mixing UDCA with DCA. UDCA activated Nrf2 signaling to increase GPX1 and catalase expression, and protective effects of UDCA pretreatment were blocked by siRNA knockdown of these antioxidants. UDCA increases expression of antioxidants that prevent toxic bile acids from causing DNA damage and NF-?B activation in Barrett's metaplasia. Elucidation of this molecular pathway for UDCA protection provides rationale for clinical trials on UDCA for chemoprevention in Barrett's esophagus.

SUBMITTER: Peng S

PROVIDER: S-EPMC4101678 | biostudies-literature | 2014 Jul

REPOSITORIES: biostudies-literature

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In Barrett's esophagus patients and Barrett's cell lines, ursodeoxycholic acid increases antioxidant expression and prevents DNA damage by bile acids.

Peng Sui S Huo Xiaofang X Rezaei Davood D Zhang Qiuyang Q Zhang Xi X Yu Chunhua C Asanuma Kiyotaka K Cheng Edaire E Pham Thai H TH Wang David H DH Chen Minhu M Souza Rhonda F RF Spechler Stuart Jon SJ

American journal of physiology. Gastrointestinal and liver physiology 20140522 2

Hydrophobic bile acids like deoxycholic acid (DCA), which cause oxidative DNA damage and activate NF-κB in Barrett's metaplasia, might contribute to carcinogenesis in Barrett's esophagus. We have explored mechanisms whereby ursodeoxycholic acid (UDCA, a hydrophilic bile acid) protects against DCA-induced injury in vivo in patients and in vitro using nonneoplastic, telomerase-immortalized Barrett's cell lines. We took biopsies of Barrett's esophagus from 21 patients before and after esophageal pe ...[more]

PMID: 24852569

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Project description: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.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.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.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.

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Dataset Information

In Barrett's esophagus patients and Barrett's cell lines, ursodeoxycholic acid increases antioxidant expression and prevents DNA damage by bile acids.

Publications

In Barrett's esophagus patients and Barrett's cell lines, ursodeoxycholic acid increases antioxidant expression and prevents DNA damage by bile acids.

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