Background & Aims: Mechanisms of the progression from Barrett’s esophagus (BE) to esophageal adenocarcinoma (EA) are not fully understood. Bile acids may play an important role in this progression. The aim of this study is to examine the role of NADPH oxidase NOX5-S and a novel bile acid receptor TGR5 in taurodeoxycholic acid (TDCA)-induced increase in cell proliferation.
Methods: Human Barrett’s cell line BAR-T and EA cell line FLO were transfected by using Lipofectamine 2000 or Amaxa-Nucleofector-System. mRNAs were measured by real-time PCR. H2O2 was measured by a fluorescent assay. Cell proliferation was determined by measurement of thymidine incorporation.
Results: NOX5-S was present in FLO cells. TDCA significantly increased NOX5-S expression, H2O2 production and thymidine incorporation in FLO and BAR-T cells. This increase in thymidine incorporation was significantly reduced by knockdown of NOX5-S. TGR5 mRNA and protein levels were significantly higher in EA tissues than in normal esophageal mucosa or Barrett’s mucosa. Knockdown of TGR5 markedly inhibited TDCA-induced increase in NOX5-S expression, H2O2 production and thymidine incorporation in FLO and BAR-T cells. Overexpression of TGR5 significantly enhanced TDCA’s effects in FLO cells. TGR5 receptors were coupled with Gαq and Gαi-3 proteins, but only Gαq mediated TDCA-induced increase in NOX5-S expression, H2O2 production and thymidine incorporation in FLO cells.
Conclusions: TDCA-induced increase in cell proliferation depends on upregulation of NOX5-S expression in BAR-T and FLO cells. TDCA-induced NOX5-S expression may be mediated by activation of the TGR5 receptor and Gαq protein. Our data may provide potential targets to prevent and/or treat Barrett’s EA.