Helicobacter pylori FKBP-type PPIase promotes gastric epithelial cell proliferation and anchorage-independent growth through activation of ERK-mediated mitogenic signaling pathway

Though Helicobacter pylori (H. pylori) has been classified as class I carcinogen, key virulence factor(s) generated by H. pylori that causes gastric cancer remains to be fully determined. Here, we show that deletion of peptidyl-prolyl cis–trans isomerase (PPIase) prevented H. pylori from stimulating human gastric epithelial cell (AGS) proliferation. Consistent with this observation, ectopic expression of H. pylori PPIase promoted AGS cell proliferation and anchorage-independent growth. To gain insight into the biochemical mechanism of PPIase-induced effect, early signal events involved in mitogenic signaling pathways were evaluated. Expression of H. pylori PPIase caused an increase in basal as well as EGF-stimulated phosphorylation of ERK and EGF receptor at Tyr1086. Treatment with MEK inhibitor completely blocked PPIase-induced cell proliferation. Our results suggest that H. pylori PPIase has the potential to activate mitogenic signaling pathway and to promote transformation of gastric epithelial cells. H. pylori PPIase may represent a novel target for therapeutic management of gastric cancer patients. This study reveals a role of the recently identified gastric cancer-associated Helicobacter pylori gene-encoding FKBP-type PPIase in promoting gastric epithelial cell transformation.