Effect of Helicobacter bilis infection on human bile duct cancer cells

Abstract

Background: Helicobacter pylori infection is known to be associated with chronic atrophic gastritis, peptic ulcers, and gastric malignancies. However, the effects of other Helicobacter species have not been investigated extensively. In mice, a close relationship is observed between Helicobacter hepaticus and hepatocellular carcinoma, and Helicobacter species can be found in humans, most commonly in extragastric organs. There have also been reports that H. bilis may be associated with biliary malignancies in humans. The effect of H. bilis infection on a human bile duct cancer cell line was investigated in this study.

Methods: We prepared HuCCT-1, the human bile duct cancer cell line, which was cocultured with H. bilis and cultured alone as a control. HuCCT-1 with and without H. bilis were transfected with the NF-kappaB, E2 transcription factor (E2F), and cyclic AMP response element (CRE) luciferase vectors. The activity of NF-kappaB between H. bilis and the infected and noninfected HuCCT-1 cells was also measured by dual luciferase reporter assay. The concentration of vascular endothelial growth factor (VEGF) in the cocultured medium and control medium were measured by ELISA. To investigate the effect of H. bilis infection on HuCCT-1 with regard to human umbilical vein endothelial cell (HUVEC) tube formation, HUVECs and fibroblasts were cocultured in 24-well plates with and without the conditioned medium.

Results: NF-kappaB, E2F and CRE activity, production of VEGF, and angiogenesis in H. bilis-infected cell lines were enhanced compared with controls.

Conclusions: H. bilis infection in a human bile duct cancer cell line activates transcript factors such as NF-kappaB that stimulate production of VEGF and lead to enhancement of angiogenesis. H. bilis infection may play an important role in malignancies in the biliary tract.