Ursodeoxycholic Acid Suppresses Epithelial-Mesenchymal Transition via Inhibition of Reactive Oxygen Species in Bile Duct Cancer Cells

Background/Aim: Reactive oxygen species (ROS) are associated with the growth and invasion of malignant tumors. Ursodeoxycholic acid (UDCA) was proven to block the EGFR-MAPK signaling pathway and epithelial-mesenchymal transition (EMT) in bile duct cancer (BDC) cells. This study was performed to determine the effect of UDCA on ROS activity in BDC cells.Methods: Human extrahepatic BDC cells were cultured. MTT assays evaluated cell viability, and ROS assay kit measured ROS. The western blot assays measured the expression levels of various target proteins. SiRNA was used for silencing of specific genes, and shRNA was used for over-expression of specific genes.Results: UDCA suppressed DCA-induced production of peroxide and ROS, inhibited expression of PRX2, phosphorylated STAT3 and SOD2, and decreased expression of NOX2 and NOX4 in BDC cells. PRX2 and STAT3 were involved in inhibiting EMT by UDCA. UDCA restored the expression of catalase inhibited by DCA in BDC cells. Furthermore, overexpression of NOX4 using shRNA offset the antineoplastic effect of UDCA in BDC cells.Conclusions: UDCA suppresses the production of ROS and enhances the elimination of ROS, inhibiting STAT3 and PRX2 associated with EMT in BDC cells. Accordingly, UDCA contributes to inhibiting the growth and invasiveness of BDC cells via suppression of ROS activity and EMT.