As a commensal or a pathogen, Helicobacter pylori can change the balance of a complex interaction that exists among gastric epithelial cells, microbes, and their environment. Therefore, unraveling this complex relationship of these mixtures can be expected to help prevent cancer as well as troublesome unmet medical needs of H. pylori infection. Though gastric carcinogenesis is a multi-step process, precancerous lesion can be reversible in the early phase of mucosal damage before reaching the stage of no return. However, biomarkers to predict rejuvenation of precancerous atrophic gastritis have not been identified yet and gastric cancer prevention is still regarded as an impregnable fortress. However, when we take the journey from H. pylori-associated gastritis to gastric cancer, it provides us with the clue for prevention since there are two main preventive strategies: eradication and anti-inflammation. The evidence supporting the former strategy is now ongoing in Japan through a nation-wide effort to eradicate H. pylori in patients with chronic gastritis, but suboptimal apprehension to increasing H. pylori resistance to antibiotics and patient non-compliance still exists. The latter strategy has been continued in the author's research center under siTRP (short-term intervention to revert premalignant lesion) strategy. By focusing on the role of inflammation in the development of H. pylori-associated gastric carcinogenesis, this review is intended to explain the connection between inflammation and gastric cancer. Strategies on H. pylori eradication, removal of inflammation, and reverting preneoplastic lesion will also be introduced. In the end, we expect to be able to prevent gastric cancer by take a detour from the unpleasant journey, i.e. from H. pylori-associated gastritis to gastric cancer.
Animals ; Anti-Bacterial Agents/pharmacology/therapeutic use ; Biomarkers/metabolism ; Disease Models, Animal ; Gastritis/*etiology ; Helicobacter Infections/*complications/drug therapy ; Helicobacter pylori/drug effects/metabolism/physiology ; Humans ; Stomach Neoplasms/etiology/*prevention & control ; Virulence Factors/metabolism

OBJECTIVETo investigate the relationship between point mutation of penicillin-binding protein gene (pbp) and amoxicillin resistance (AMOgamma) of Helicobacter pylori (H. pylori) as well as to compare the protein profiles under proteomic technology to get the candidate resistance-related proteins.

METHODS(1) AMOgamma strains were selected from the sensitive H. pylori strain 26695 by serial passage technique in vitro. (2) Point mutations of five putative resistance genes (HP0597, HP1565, HP1542, HP1556, and HP0160) were analyzed by denaturing high-performance liquid chromatography (DHPLC) and DNA sequencing. (3) Proteins samples were separated by two-dimensional electrophoresis (2-DE). Protein profiles were compared between the AMOgamma strain obtained in vitro and its sensitive parent strain 26695. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) was performed to identify the proteins of interest. The proteins were searched by software MASCOT and identified by peptide fingerprint map using the program MS-FIT of Protein Prospect.

RESULTS(1) An AMOgamma strain (MIC 8 microg/ml) was obtained. Complete loss of the resistant phenotype was observed after cultivation in the absence of AMO or storage at - 80 degrees C. (2) DHPLC and Sequencing result showed no point mutations in five pbp genes in the AMOgamma strain when compared with the corresponding PCR products from its parent strain 26695. (3) Protein profiling showed that eleven protein spots were differently expressed between 26695 and the AMOgamma strain. Of these protein spots in the AMOgamma strain, two new spots (Spot 1 and Spot 2) were observed with one (Spot 3) was up-regulated three-fold and the remained ones (Spot 4-11) were down-regulated.

CONCLUSIONAMO resistance of H. pylori might be resulted from, unstable phenotype change rather than point mutations of pbp genes. These differentially regulated proteins in AMOgamma strain might play a role in development of resistance to AMO in H. pylori.

Amoxicillin ; pharmacology ; Anti-Bacterial Agents ; pharmacology ; Bacterial Proteins ; genetics ; metabolism ; Chromatography, High Pressure Liquid ; Drug Resistance, Bacterial ; genetics ; Electrophoresis, Gel, Two-Dimensional ; Helicobacter pylori ; drug effects ; genetics ; metabolism ; Point Mutation ; genetics ; physiology ; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization

Helicobacter pylori (H. pylori) induces the activation of nuclear factor-kB (NF-kappaB) and cytokine expression in gastric epithelial cells. The Janus kinase/signal transducers and activators of transcription (Jak/Stat) cascade is the inflammatory signaling in various cells. The purpose of the present study is to determine whether H. pylori-induced activation of NF-kappaB and the expression of interleukin-8 (IL-8) are mediated by the activation of Jak1/Stat3 in gastric epithelial (AGS) cells. Thus, gastric epithelial AGS cells were infected with H. pylori in Korean isolates (HP99) at bacterium/cell ratio of 300:1, and the level of IL-8 in the medium was determined by enzyme-linked immonosorbent assay. Phospho-specific and total forms of Jak1/Stat3 and IkappaBalpha were assessed by Western blot analysis, and NF-kappaB activation was determined by electrophoretic mobility shift assay. The results showed that H. pylori induced the activation of Jak1/Stat3 and IL-8 production, which was inhibited by a Jak/Stat3 specific inhibitor AG490 in AGS cells in a dose-dependent manner. H. pylori-induced activation of NF-kappaB, determined by phosphorylation of IkappaBalpha and NF-kappaB-DNA binding activity, were inhibited by AG490. In conclusion, Jak1/Stat3 activation may mediate the activation of NF-kappaB and the expression of IL-8 in H. pylori-infected AGS cells. Inhibition of Jak1/Stat3 may be beneficial for the treatment of H. pylori-induced gastric inflammation, since the activation of NF-kappaB is inhibited and inflammatory cytokine expression is suppressed.
Blotting, Western ; DNA, Bacterial/analysis/genetics ; Epithelial Cells/metabolism ; Gastric Mucosa/drug effects/*immunology/microbiology ; Gene Expression Regulation/drug effects/*immunology ; Gene Expression Regulation, Bacterial ; Helicobacter Infections/immunology/*metabolism ; Helicobacter pylori/genetics/pathogenicity/*physiology ; Humans ; Interleukin-8/genetics/*metabolism ; Janus Kinase 1 ; NF-kappa B/biosynthesis/*metabolism ; Phosphorylation ; RNA, Messenger/metabolism ; STAT3 Transcription Factor ; Signal Transduction/genetics

Helicobacter pylori (H. pylori) induces the activation of nuclear factor-kB (NF-kappaB) and cytokine expression in gastric epithelial cells. The Janus kinase/signal transducers and activators of transcription (Jak/Stat) cascade is the inflammatory signaling in various cells. The purpose of the present study is to determine whether H. pylori-induced activation of NF-kappaB and the expression of interleukin-8 (IL-8) are mediated by the activation of Jak1/Stat3 in gastric epithelial (AGS) cells. Thus, gastric epithelial AGS cells were infected with H. pylori in Korean isolates (HP99) at bacterium/cell ratio of 300:1, and the level of IL-8 in the medium was determined by enzyme-linked immonosorbent assay. Phospho-specific and total forms of Jak1/Stat3 and IkappaBalpha were assessed by Western blot analysis, and NF-kappaB activation was determined by electrophoretic mobility shift assay. The results showed that H. pylori induced the activation of Jak1/Stat3 and IL-8 production, which was inhibited by a Jak/Stat3 specific inhibitor AG490 in AGS cells in a dose-dependent manner. H. pylori-induced activation of NF-kappaB, determined by phosphorylation of IkappaBalpha and NF-kappaB-DNA binding activity, were inhibited by AG490. In conclusion, Jak1/Stat3 activation may mediate the activation of NF-kappaB and the expression of IL-8 in H. pylori-infected AGS cells. Inhibition of Jak1/Stat3 may be beneficial for the treatment of H. pylori-induced gastric inflammation, since the activation of NF-kappaB is inhibited and inflammatory cytokine expression is suppressed.
Blotting, Western ; DNA, Bacterial/analysis/genetics ; Epithelial Cells/metabolism ; Gastric Mucosa/drug effects/*immunology/microbiology ; Gene Expression Regulation/drug effects/*immunology ; Gene Expression Regulation, Bacterial ; Helicobacter Infections/immunology/*metabolism ; Helicobacter pylori/genetics/pathogenicity/*physiology ; Humans ; Interleukin-8/genetics/*metabolism ; Janus Kinase 1 ; NF-kappa B/biosynthesis/*metabolism ; Phosphorylation ; RNA, Messenger/metabolism ; STAT3 Transcription Factor ; Signal Transduction/genetics