Impact of Deoxycholic Acid on Oesophageal Adenocarcinoma Invasion: Effect on Matrix Metalloproteinases.

Bile acids (BAs) have been implicated in the development of oesophagitis, Barrett's oesophagus and oesophageal adenocarcinoma (OAC). However, whether BAs promote cancer invasiveness has not been elucidated. We evaluated the role of BAs, in particular deoxycholic acid (DCA), in OAC invasion. Migration and invasiveness in untreated and BA-treated oesophageal SKGT-4 cancer cells were evaluated. Activity and expression of different matrix metalloproteinases (MMPs) were determined by zymography, ELISA, PCR and Western blot. Finally, human OAC tissues were stained for MMP-10 by immunohistochemistry. It was found that SKGT-4 cells incubated with low concentrations of DCA had a significant increase in invasion. In addition, MMP-10 mRNA and protein expression were also increased in the presence of DCA. MMP-10 was found to be highly expressed both in-vitro and in-vivo in neoplastic OAC cells relative to non-neoplastic squamous epithelial cells. Our results show that DCA promotes OAC invasion and MMP-10 overexpression. This study will advance our understanding of the pathophysiological mechanisms involved in human OAC and shows promise for the development of new therapeutic strategies.

A fluorescent analogue of tauroursodeoxycholic acid reduces ER stress and is cytoprotective.

Tauroursodeoxycholic acid (TUDCA) is a cytoprotective ER stress inhibitor and chemical chaperone. It has therapeutic potential in a wide array of diseases but a specific macromolecular target or molecular mechanism of action remains obscure. This Letter describes an effective new synthetic approach to taurine conjugation of bile acids which we used to prepare 3α-dansyl TUDCA (4) as a probe for TUDCA actions. As a model of ER stress we used the hepatocarcinoma cell line HUH7 and stimulation with either deoxycholic acid (DCA, 200µM) or tunicamycin (5µg/ml) and measured levels of Bip/GRP78, ATF4, CHOP and XBP1s/XBP1u. Compound 4 was more effective than UDCA at inhibiting ER stress markers and had similar effects to TUDCA. In a model of cholestasis using the cytotoxic DCA to induce apoptosis, pretreatment with 4 prevented cell death similarly to TUDCA whereas the unconjugated clinically used UDCA had no effect. 3α-Dansyl TUDCA (4) appears to be a suitable reporter for TUDCA effects on ER stress and related cytoprotective activity.