Helicobacter pylori infection and molecular changes in gastric carcinogenesis

Inhibitory activity of Limosilactobacillus reuteri isolated from camel milk against Helicobacter pylori effects in human gastric epithelial cells

This study aimed to evaluate anti-Helicobacter pylori effects of Limosilactobacillus reuteri 2892 (L. reuteri 2892) isolated from camel milk in GC cell lines (AGS and MKN). From 15 camel milk samples, 132 microbial strains were isolated. Based on microbial and biochemical analysis, 11 potential probiotic candidates were selected. The potential probiotic candidates were assayed for anti-H. pylori activity, and the strain with the highest anti-H. pylori activity was identified genotypically. Based on 16S rDNA sequencing, the selected strain with the best activity against H. pylori (inhibition zone = 15.5 ± 0.8) belonged to the Lactobacillus reuteri strain 2892. Cell treatment with H. pylori HC-113 inhibits gene expression of Claudin-4, ZO-1, MUC5AC, and MUC2 in gastric cells, which are attenuated by L. reuteri 2892. The simulative effects of H. pylori HC-113 on the cell migration and invasion of gastric cells were lost when cells were cotreated with L. reuteri 2892. Cell treatment with H. pylori HC-113 promoted cell death, whereas cotreatment with L. reuteri 2892 markedly decreased necrotic and late apoptotic cells. The present study demonstrates that L. reuteri 2892 has potent anti-H. pylori effects and thus can be considered as an alternative protective agent against inflammatory effects of H. pylori in gastric cells.

Research and clinical applications of molecular biomarkers in gastrointestinal carcinoma (Review)

Gastrointestinal (GI) carcinoma is a common malignant disease worldwide. Its development and progression is a multistage process involving a multifactorial etiology. Although the detailed mechanisms of the development of GI carcinoma remain controversial, the elucidation of its molecular biology over the last few years has resulted in a better perspective on its epidemiology, carcinogenesis and pathogenesis. More significantly, it is currently possible to use biological indicators or biomarkers in differential diagnosis, prognostic evaluation and specific clinical interventions. In this review, we aimed to describe the biomarkers of pathogenesis, invasion, metastasis and prognosis of GI carcinoma and discuss their potential clinical applications. The majority of these biomarkers, such as tumor-associated antigens, oncogenes and tumor suppressor genes, metastasis-associated genes, cell adhesion molecules, cytokines, growth factors and microRNAs, are currently broadly applicable.

Helicobacter pylori induces promoter hypermethylation and downregulates gene expression of IRX1 transcription factor on human gastric mucosa

BACKGROUND AND AIM

Gene silence of IRX1 tumor suppressor by promoter CpG methylation combined with loss of heterozygosity (LOH) has been identified in human gastric cancer. This study investigated the association between methylation of IRX1 and Helicobacter pylori infection in gastric mucosa tissues and cell line.

METHODS

IRX1 methylation was studied by methylation specific polymerase chain reaction (MSP) and bisulfate sequencing polymerase chain reaction (BSP) methods in gastric mucosa tissues from H. pylori-positive chronic gastritis patients or H. pylori-negative chronic gastritis patients. Promoter activity, methylation status and gene expressing level of IRX1 were evaluated by persistent infecting H. pylori on human gastric cells GES-1 in vitro. Electron microscopy was used to observe the effect of H. pylori infection on GES-1 gastric mucosa cells.

RESULTS

The methylation level of IRX1 promoter in H. pylori positive chronic gastritis and H. pylori negative chronic gastritis was 55.30%±13.17 versus 5.20%±6.31, respectively (P<0.01). H. pylori infection stimulated increased microvillus, and mucous secretion on GES-1 cells. Infection of H. pylori induced IRX1 promoter methylation and downregulation of the promoter activity as well as gene expression significantly.

CONCLUSIONS

This study firstly demonstrated that H. pylori infection contributes to IRX1 promoter methylation on gastric mucosa.

Lack of enhancing effects of degraded lambda-carrageenan on the development of beta-catenin-accumulated crypts in male DBA/2J mice initiated with azoxymethane

Effect of degraded lambda-carrageenan, which induces colitis in rodents, on the development of beta-catenin-accumulated crypts (BCAC) being putative precancer lesions of colon cancer was investigated in male DBA/2J mice initiated with azoxymethane (AOM). In a preliminary experiment, male DBA/2J mice among seven different strains (A/J, BALB/c, C3H/HeN, C57BL/6J, CBA/N, DBA/1J, and DBA/2J) of male mice were most sensitive to degraded lambda-carrageenan. Therefore, male DBA/2J mice were intraperitonially injected AOM (10 mg/kg body weight), and then 2% degraded lambda-carrageenan in drinking water for one or two weeks, starting one week after dosing of AOM. Thereafter animals were no further treated up to week 26. At week 26, the frequency of BCAC in the colonic mucosa was 12.50+/-2.46 in the AOM alone group, 11.30+/-3.50 in the AOM/degraded lambda-carrageenan (for one week) group, and 11.60+/-2.27 in the AOM/degraded lambda-carrageenan (for two weeks) group. The findings suggest that degraded lambda-carrageenan treatment for one or two weeks did not affect the occurrence of BCAC. Our results may indicate no enhancing or promoting effects of degraded lambda-carrageenan on colon carcinogenesis in mice initiated with AOM.

Restoration of heat shock protein70 suppresses gastric mucosal inducible nitric oxide synthase expression induced by Helicobacter pylori

Heat shock proteins (HSPs) are crucial for the maintenance of cell integrity during normal cellular growth as well as during pathophysiological conditions. While functioning mainly as molecular chaperones, HSPs also appear to be involved in diverse biological activities, such as apoptosis, carcinogenesis, and cytoprotection from cytotoxic damage. Infection with Helicobacter pylori causes inflammation in the gastric mucosa, leading to gastritis, gastric ulcers, duodenal ulcer disease, and even gastric cancer, but the role of HSPs in H. pylori-associated gastropathy is not known. Using two-dimensional electrophoretic analysis, we have observed significant shifts in HSP profiles after H. pylori infection in RGM-1 cells. We therefore evaluated the effect of treatments that induce HSPs on H. pylori-induced inducible nitric oxide synthase (iNOS) expression. We found that H. pylori infection significantly attenuated the expression of HSP70, whereas exposure of cells to noncytotoxic heat shock or geranylgeranylacetone restored HSP70 expression, as well as suppressing the expression of iNOS, a major cause of H. pylori-induced gastric tissue damage. Our results suggest that induction of HSP70 confers cytoprotection against H. pylori infection by inhibiting the expression of iNOS. In conclusion, these results provide important insights into the flux in HSPs profiles in response to H. pylori infection and highlight the cytoprotective role of HSP70 in H. pylori infection.

Blockage of HSP 90 modulates Helicobacter pylori-induced IL-8 productions through the inactivation of transcriptional factors of AP-1 and NF-kappaB

Helicobacter pylori infection leads to significant inflammations in the gastric mucosa, which is closely associated with development of gastric cancer. Heat shock protein 90 (HSP 90) has been revealed to be critical for intracellular signaling that participates in inflammatory response as well as carcinogenesis. In this study, we investigated a regulatory role of HSP 90 in H. pylori-induced IL-8 production. Our results showed that H. pylori stimulated significant phosphorylation of HSP 90 and the phosphorylation was diminished by administration of HSP 90 inhibitor, geldanamycin (GA). Treatment of GA completely inhibited H. pylori-induced IL-8 production due to deactivation of ERK1/2 and NF-kappaB. These results subsequently lead to inactivation of AP-1 and NF-kappaB, which are known to be major transcriptional factors of IL-8. Our data provide important insights that HSP 90 is involved as a crucial regulator in H. pylori-induced IL-8 production and its inhibitor could be potentially used for the inhibition of H. pylori-provoked inflammation.

Investigation of Helicobacter pylori colonization in laryngeal neoplasia

Helicobacter pylori has been investigated in several other organ systems and localizations such as the oral cavity, but has not been investigated extensively in squamous cell carcinoma of the larynx, a region that could be directly exposed to the bacterium by the oral route or gastro-esophageal reflux. Only serological studies are available regarding the relation between H. pylori and laryngeal cancer, yielding conflicting results. To our knowledge, there is no study investigating the presence of H. pylori in laryngeal squamous cell carcinoma tissue. The purpose of this study was to investigate the presence of H. pylori in laryngeal squamous cell carcinoma tissue and to investigate the possible role of this organism in the etiopathogenesis of laryngeal cancer. Specimens from 50 patients with laryngeal cancer who underwent total or partial laryngectomy between March 1999 and December 2002 were examined by histopathological and immunohistochemical methods to detect H. pylori. The presence of H. pylori was also investigated histopathologically in 50 benign laryngeal biopsy specimens. In our study, we demonstrated that H. pylori was not present in laryngeal squamous cell carcinoma tissue or in the benign lesions. We could not find any evidence indicating that H. pylori played a role at the tissue level in the pathogenesis of laryngeal carcinoma.

Old and new TNM in carcinoma of the gastric antrum: analysis of our personal experience

Various tumor node metastasis (TNM) classifications have been proposed for staging of gastric carcinoma, including the fourth edition of the TNM classification and the Japanese Research Society for Gastric Cancer (JRSGC) system. In 1997 the fifth edition of TNM classification introduced the concept of the number of metastatic lymph nodes. We review our experience with staging gastric cancer in light of both the fourth and fifth editions of the TNM classification system. From January 1986 to December 1997, we performed subtotal resection in 193 patients with carcinoma of the gastric antrum. A total of 147 patients presented with criteria from the fifth TNM edition. We compared data from these patients with data from the fourth TNM edition. We analyzed 84 females and 63 males whose average age was 68.9 years. The average number of lymph nodes removed was 16.7. We used the Kaplan-Meier method to analyze survival. In accordance with the fourth TNM edition, we recorded 82 patients who were pN0, 36 who were pN1, and 29 who were pN2; according to the fifth edition, 82 patients were pN0, 33 were pN1, 17 were pN2, and 15 were pN3. Average follow-up was 26.7 months, and average survival was 56.9 months for N0 patients, 38.7 months for N1 patients, and 24.5 months for N2 patients staged according to the fourth edition. According to the fifth edition, survival was 39.3 months for N1 patients, 33.6 months for N2 patients, and 10.3 months for N3 patients. The survival curve was statistically different (P<0.001) between N0 and N1 patients according to the fourth edition; there was no significant difference between N1 and N2 patients. According to the fifth edition, the difference in survival probability was P<0.001 between N0 and N1 patients and N2 and N3 patients. The fifth TNM edition presents a greater ease of stratification in bringing together and mediating diverse cultural experiences between West and East. This staging lays the basis for a more accurate comparison between the groups.