Infection with CagA+ Helicobacter pylori induces epithelial to mesenchymal transition in human cholangiocytes

Abstract

Recent reports suggest that the East Asian liver fluke, Opisthorchis viverrini, infection with which is implicated in opisthorchiasis-associated cholangiocarcinoma, serves as a reservoir of Helicobacter pylori. The opisthorchiasis-affected cholangiocytes that line the intrahepatic biliary tract are considered to be the cell of origin of this malignancy. Here, we investigated interactions in vitro among human cholangiocytes, a CagA-positive strain of Helicobacter pylori, and the related bacillus, Helicobacter bilis. Exposure to increasing numbers of H. pylori at 0, 1, 10, 100 bacilli per cholangiocyte induced phenotypic changes including the profusion of thread-like filopodia and a loss of cell-cell contact, in a dose-dependent fashion. In parallel, following exposure to H. pylori, changes were evident in levels of mRNA expression of epithelial to mesenchymal transition (EMT)-encoding factors including snail, slug, vimentin, matrix metalloprotease, zinc finger E-box-binding homeobox, and the cancer stem cell marker CD44. Transcription levels encoding the cell adhesion marker CD24 decreased. Analysis to quantify cellular proliferation, migration and invasion in real time using the xCELLigence approach revealed that exposure to [≥]10 H. pylori stimulated migration and invasion by the cholangiocytes through an extracellular matrix. In addition, 10 bacilli of CagA-positive H. pylori stimulated contact-independent colony establishment in soft agar. These findings support the hypothesis that infection with H. pylori contributes to the malignant transformation of the biliary epithelium.