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World J Gastroenterol. May 14, 2013; 19(18): 2736-2739
Published online May 14, 2013. doi: 10.3748/wjg.v19.i18.2736
Relationships of CDXs and apical sodium-dependent bile acid transporter in Barrett’s esophagus
Jingbo Zhao, Hans Gregersen
Jingbo Zhao, Mech-Sense, Department of Gastroenterology and Surgery, Aalborg University Hospital, DK-9000 Aalborg, Denmark
Jingbo Zhao, Hans Gregersen, College of Bioengineering, Chongqing University, Chongqing 400044, China
Hans Gregersen, the Giome Institute, DK-8000 Aarhus, Denmark
Author contributions: Zhao J designed and drafted the manuscript; Gregersen H edited English language and grammar; Zhao J and Gregersen H revised and finally approved this paper.
Correspondence to: Jingbo Zhao, MD, PhD, Mech-Sense, Department of Gastroenterology and Surgery, Aalborg University Hospital, Sdr. Skovvej 15, DK-9000 Aalborg, Denmark. jz@rn.dk
Telephone: +45-9-9326907 Fax: +45-9-9326801
Received: April 2, 2013
Revised: May 2, 2013
Accepted: May 7, 2013
Published online: May 14, 2013
Processing time: 42 Days and 12 Hours
Abstract

Barrett’s esophagus (BE) is characterized by intestinal metaplasia with the differentiated epithelium replaced by another type of epithelium morphologically similar to normal intestinal epithelium. The metaplasia is preceded by bile and acid reflux into the esophagus. BE is a premalignant condition associated with increased risk of esophageal cancer, especially esophageal adenocarcinoma. The Caudal-related homeodomain transcription factors Caudal-related homeodomain transcription factor CDX1 and CDX2 are expressed exclusively in the small and large intestine, playing important roles in proliferation and differentiation of intestinal epithelial cells. Ectopic expression of CDX1 and CDX2 occurs in BE. The apical sodium-dependent bile acid transporter (ASBT) is expressed primarily in terminal ileum where it is a key factor for intestinal reabsorption of bile salts. In addition to upregulation of CDX1 and CDX2, ASBT expression is up-regulated in BE. Furthermore, both CDX1/CDX2 and ASBT expressions are down-regulated in high-grade esophageal dysplasia. The alteration of the above-mentioned factors calls for attention: what is the relationship between CDXs and ASBT aberrant expression in BE? In this commentary, we discuss this issue on basis of the recent study done by Ma et al.

Keywords: Esophagus; Intestinal metaplasia; Caudal-related homeodomain transcription factors; Apical sodium-dependent bile acid transporter; Aberrant expression

Core tip: Aberrant co-expression of Caudal-related homeodomain transcription factors (CDXs) and apical sodium-dependent bile acid transporter (ASBT) in the epithelium of Barrett’s esophagus (BE) indicates association among these factors. Acid and bile reflux induce CDXs gene expression and can lead to formation of BE. CDX-mediated promoter activation can lead to aberrant expression of ASBT. The BE phenotype may be better than squamous epithelium to protect against refluxed acid and bile. On the other hand the BE phenotype is associated with increased risk of esophageal adenocarcinoma (EAC). Furthermore, the decreased expressions of CDXs and ASBT in high-grade esophageal dysplasia indicate that CDXs and ASBT are inhibitory factors to the progression of EAC.