Proteomic Analysis of Human Gastric Adenocarcinoma Epithelial AGS Cells Following Transfection of Helicobacter pylori Cytotoxin-associated Gene A

Abstract: Helicobacter pylori (Hp) cytotoxin-associated protein A (CagA) is closely associated with gastritis， peptic ulcer and gastric carcinoma. Tyrosine-phosphorylation of C-terminal region repeat sequence(s) is considered playing an important role in the biological function of CagA. To identify the host cell proteins involved in CagA induced pathogenesis and investigate whether the changes of protein expression depend on the tyrosine-phosphorylation of CagA， protein expression profiles were analyzed in human gastric adenocarcinoma epithelial AGS cells transfected with wild type cagA and phosphorylation site mutant cagA using ProteinChips and surface enhanced laser desorption/Ionization time-of-flight mass spectrometry (SELDI-TOF-MS) proteomics technology. The profiles showed the expression level of 10 proteins at mass/charge ratios (m/z) of 4229， 4714， 4728， 5129， 6546， 6657， 8162， 9084， 13803， 14021 were up-regulated while 6 proteins at m/z of 2013， 4286， 8563， 9952， 11085， 11645 were down-regulated after wild type cagA transfection， indicating that these 16 proteins might have relationships with CagA induced pathogenesis. Besides， only 4 proteins at m/z of 4714， 4728， 6 546， 6656 among the 16 proteins mentioned above were found up-regulated after mutant cagA transfection， suggesting these expression changes were independent of the tyrosine-phosphorylation of CagA while the changes of other 12 proteins were dependent of the tyrosine-phosphorylation of CagA. These results may provide new targets for further understanding of the biological function and pathogenesis of CagA.

CSTR: 32200.14.cjcb.2006.04.0023