Evaluation of Cell- Morphological Changes by Helicobacter pylori CagA and Pragmin in AGS Human Gastric Carcinoma Cells

Abstract

Background: Helicobacter pylori CagA oncoprotein was injected into mammalian host cells via type IV secretion system, where it was tyrosine phosphorylated at the Glu-Pro-Ile-Tyr-Ala (EPIYA) sequence. Tyrosine phosphorylation of CagA was shown to be a prerequisite for the induction of actin cytoskeletal rearrangement in AGS gastric epithelial cells. The needle-like projections, known as the hummingbird phenotype, are thought to be involved in gastric disease. Moreover, Pragmin, a mammalian protein, contains a single EPIYA motif, and tyrosine phosphorylation of Pragmin at EPIYA motif in AGS cells induce cell-morphological changes, which are characterized by elongated cell shape with invasive phenotype that contributes to tumor invasion and metastasis. Methods: In this study, AGS cells were transfected by CagA or/and Pragmin using lipofectamine 2000 reagent, then, cell-morphological changes were investigated using light microscope. Finally, elongated cells were counted and the results were compared. Results: Our results revealed that there is a competition between CagA and Pragmin to interact with CSK via EPIYA motif. We also found that although the cell-morphological changes are particularly dependent on tyrosine phosphorylation at EPIYA motifs in both, changes of cell morphology are different in CagA and Pragmin transfected cells. Conclusions: Our findings suggest that the mechanisms inducing the elongated cell morphology in CagA or Pragmin transfected cells may be different.