Helicobacter pylori γ-glutamyl transpeptidase-induced Ca(2+) release via PLC-IP3 receptors in AGS cells.

ABSTRACT

In our previous study, γ-glutamyl transpeptidase (GGT) isolated from Helicobacter pylori induced apoptosis of AGS cells. Here, we investigate Ca(2+) effects on GGT-induced apoptosis. The GGT transiently and significantly increased intracellular Ca(2+) concentration ([Ca(2+)]i) in AGS cells in a dose-dependent manner (P < 0.05). The GGT-induced Ca(2+) increase resulted from Ca(2+) influx and release through the phospholipase C - inositol 1,4,5-trisphosphate (PLC-IP3) pathway. The GGT-induced apoptosis was significantly reduced by treatment with U73122 (a PLC inhibitor) and xestospongin (an IP3 receptor antagonist) (P < 0.05). These results indicate that GGT could induce apoptosis of AGS cells by high levels of [Ca(2+)]i.