Infection with Helicobacter pylori Induces Epithelial to Mesenchymal Transition in Human Cholangiocytes

Abstract

Recent reports suggest that the East Asian liver fluke infection, caused by <i>Opisthorchis viverrini</i>, which is implicated in opisthorchiasis-associated cholangiocarcinoma, serves as a reservoir of <i>Helicobacter pylori</i>. 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, <i>Helicobacter pylori</i> strain NCTC 11637, and the congeneric bacillus, <i>Helicobacter bilis</i>. Exposure to increasing numbers of <i>H. pylori</i> at 0, 1, 10, 100 bacilli per cholangiocyte of the H69 cell line 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 <i>H. pylori</i>, 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. Analysis to quantify cellular proliferation, migration, and invasion in real-time by both H69 cholangiocytes and CC-LP-1 line of cholangiocarcinoma cells using the xCELLigence approach and Matrigel matrix revealed that exposure to &ge;10 <i>H. pylori</i> bacilli per cell stimulated migration and invasion by the cholangiocytes. In addition, 10 bacilli of <i>H. pylori</i> stimulated contact-independent colony establishment in soft agar. These findings support the hypothesis that infection by <i>H.</i><i>pylori</i> contributes to the malignant transformation of the biliary epithelium.