• Asian Pacific Journal of Cancer Prevention
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• v.13 no.12
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• pp.6305-6310
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• 2012

Objectives: This study aimed to demonstrate the tyrosine phosphorylation motif (TPM) and 3' region structure of the Helicobacter pylori CagA gene as well as its SHP-2 binding activity in AGS cells and relation to gastric carcinogenesis. Methods: Sixteen clinical isolate H. pylori strains from eight duodenal ulcer and eight gastric adenocarcinoma patients were studied for CagA repeat sequence EPIYA motifs, C-terminal structure, and western blot analysis of CagA protein expression, translocation, and SHP-2 binding in AGS cells. Results: Except for strain 547, all strains from the gastric adenocarcinoma patients were positive for CagA by PCR and had three EPIYA copy motifs. Western blotting showed that all strains were positive for CagA protein expression (100%), CagA protein translocation (100%), and SHP-2 binding (100%). CagA protein expression was significantly higher in the gastric adenocarcinoma patients than in the duodenal ulcer patients (P=0.0023). CagA protein translocation and SHP-2 binding in the gastric adenocarcinoma patients were higher than those in the duodenal ulcer patients, but no significant differences were found between the two groups (P=0.59, P=0.21, respectively). Conclusions: The TPMs and 3' region structures of the H. pylori CagA gene in the duodenal ulcer and gastric adenocarcinoma patients have no significant differences.

• Journal of Life Science
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• v.14 no.6 s.67
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• pp.906-912
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• 2004

Helicobacter pylori infection is highly prevalent, as high as 2/3 of whole population infected, in Korea. H. pylori infection initiates inflammation by induction of interleukin-8 through type IV secretion of CagA. It was recently suggested that induction failure of IL-8 is not associated with defect in cag PAI but associated with cagE locus diversity. This study was designed to investigate ability of 11-8 in-duction according to sequence variation within the cagE gene, cagA TP motifs and vacA m-types in vitro study using AGS cell-line, and to evaluate its association with different clinical outcome. Seventy-four H. pylori stains were isolated from 23 patients with gastric cancer (Ca), 24 subjects with gastritis (G) and 27 patients with duodenal ulcer (Du) in Kangnam St. Mary's Hospital, Seoul, Korea. cagE gene diversity was confirmed by the PCR-RFLP methods with MboI/NlaIII and tyrosine phosphate motifs (TPMs) of cagA was determined TPM-A and C by using DdeI/Tsp5091 restriction enzyme and TPM-B was determend by Real time PCR the method of Owen et al. and IL-8 was measured by ELISA assay. IL-8 activity was positively detected in 59 among 74 strains $(79.7\%)$. IL-8 secretion was significantly increased in MboI A and MboI B type compared to MboI C type and in MboI/NlaIII A-C and B-C type than C-C type. 1L-8 activity was not associated with either the number or composition of cagA tyrosine phosphorylation motifs and vacA m-type. There was no significant difference in IL-8 activity among patient groups. cagE gene diversity is thought to be mainly associated with the induction of IL-8 in H. pylori infection.