The Activation of Caspase - 3 and Mitogen - activated Protein Kinases during H . Pylori - induced Apoptosis in Gastric Cancer Cells

Kim, Won Ho; Jin, Soo Hyun; Kim, Tae Il; Yeo, Marie; Choi, Jong Won; Kim, Chul

Abstract

BACKGROUND/AIMS: Apoptosis is one of the important mechanisms of Helicobacter pylori (H. pylori)-induced epithelial cell damage. We have attempted to demonstrate the role of mitogen-activated protein (MAP) kinases in H. pylori-induced apoptosis in gastric cancer cell.
METHODS
H. pylori (ATCC 43504) and AGS cell line were used. Cell survival and death were assessed by MTT assay and trypan blue dye exclusion method. Apoptosis was detected by demonstration of DNA fragmentation in agarose gel electrophoresis. Caspase-3 activity was measured by a cleavage of fluorogenic substrate, Ac-DEVD-AMC. The activation of MAP kinase was assessed by Western blot. SB203580, PD98059 and Ac-DEVD-CHO were used for the inhibition of p38 kinase, ERK and caspase-3, respectively.
RESULTS
H. pylori-induced significant cell death, the caspase-3 activation, and DNA fragmentation in AGS cells, were accompanied by the activation of all three MAP kinase subfamilies. DNA fragmentation was attenuated by Ac-DEVD-CHO, an inhibitor of caspase-3. SB203580 reduced H. pylori-induced cell death by 42.6 while PD098059 did not affect cell death. However, caspase-3 and p38 kinase were not significantly inter-linked in H. pylori-induced apoptosis.
CONCLUSIONS
These results suggest that H. pylori induce the activation of MAP kinases in AGS cells and especially, the activation of p38 kinase may play a partial but significant role in H. pylori-induced apoptosis.