PREX2 gene's expression in gastric antral epithelial cells of patients with H. pylori infection / Expressão do gene PREX2 em células epiteliais antrais gástricas em pacientes com infecção por H. pylori

ABSTRACT BACKGROUND: The Prex2 protein is a member of the Rac family proteins that belongs to small G proteins with a critical role in cell migration, cell proliferation, and apoptosis through its effects on PI3K cell signaling pathway and phosphatase activity of PTEN protein. The effect of PREX2 gene expression has been shown in some cancer cells. A survey of PREX2 gene expression in gastric antral epithelial cells of gastric cancer patients with Helicobacter pylori various genotypes infection can conduct to better understanding H. pylori infection's carcinogenesis. METHODS: In a case-control study, PREX2 gene expression was evaluated in gastric antral biopsy samples on four groups of patients referred to Sanandaj hospitals, including gastritis with (n=23) and without (n=27) H. pylori infection and gastric cancer with (n=21) and without (n=32) H. pylori infection. Each gastric biopsy sample's total RNA was extracted and cDNA synthesized by using Kits (Takara Company). The PREX2 gene expression was measured using the relative quantitative real-time RT-PCR method and ΔΔCt formula. RESULTS: The PREX2 gene expression increased in gastric antral biopsy samples of gastritis and gastric cancer patients with H. pylori infection (case groups) than patients without H. pylori infection (control groups) 2.38 and 2.27 times, respectively. The patients with H. pylori vacA s1m1 and sabB genotypes infection showed a significant increase of PREX2 gene expression in gastric cancer antral epithelial cells. CONCLUSION: H. pylori vacA s1m1 and sabB genotypes have the positive correlations with PREX2 gene expression in gastric antral epithelial cells of gastritis and gastric cancer patients.

RESUMO CONTEXTO: A proteína Prex2 é membro das proteínas da família Rac que pertencem a pequenas proteínas G com um papel crítico na migração celular, na proliferação celular e na apoptose através de seus efeitos na via de sinalização celular PI3K e atividade fosfatase da proteína PTEN. O efeito da expressão genética PREX2 tem sido mostrada em algumas células cancerosas. Um levantamento da expressão genética PREX2 em células epiteliais antrais gástricas de pacientes infectados com vários genótipos de Helicobacter pylori pode conduzir a um melhor entendimento da carcinogênese da infecção por H. pylori. MÉTODOS: Em estudo de caso-controle, a expressão genética PREX2 foi avaliada em amostras de biópsia antral gástrica em quatro grupos de pacientes encaminhados aos hospitais de Sanandaj, incluindo gastrite com (n=23) e sem (n=27) infecção por H. pylori e de câncer gástrico com (n=21) e sem (n=32) infecção por H. pylori. O RNA total de cada amostra de biópsia gástrica foi extraído e cDNA sintetizado por meio de kits (Takara Company). A expressão genética PREX2 foi medida utilizando-se o método RT-PCR em tempo real quantitativo relativo e a fórmula ΔΔCt. RESULTADOS: A expressão genética PREX2 aumentou em amostras de biópsia antral gástrica de pacientes com gastrite e câncer gástrico com infecção por H. pylori (grupos de casos) em relação aos sem infecção por H. pylori (grupos de controle) 2,38 e 2,27 vezes, respectivamente. Os pacientes com infecção por genótipos H. pylori vacA s1m1 e sabB apresentaram um aumento significativo da expressão genética PREX2 em células epiteliais antrais de câncer gástrico. CONCLUSÃO: Os genótipos H. pylori vacA s1m1 e sabB têm correlações positivas com a expressão genética PREX2 em células epiteliais antrais gástricas de pacientes com câncer gástrico e gastrites.

Increased expression of interleukin-6 gene in gastritis and gastric cancer

Helicobacter pylori (H. pylori) induces an intense inflammatory response, mediated by proinflammatory cytokines, including interleukin (IL)-6 and its membrane receptor (IL-6R), which activates important signaling pathways in the development of gastric disease and cancer. We investigated the gene and protein expression of IL-6 and IL-6R and the influence of polymorphisms rs1800795, rs1800796, and rs1800797 on its gene expression together with H. pylori infection. Furthermore, an in-silico analysis was performed to support our results. Gastric biopsies were obtained from patients with gastric symptoms and patients with gastric cancer (GC) and were divided into groups (Control, Gastritis, and Cancer). H. pylori was detected by PCR. Real-time-qPCR was employed to determine gene expression, and western blot assay was used to analyze protein expression levels. PCR-RFLP was used to characterize IL-6 polymorphisms. Bioinformatics analyses were performed using the Gene Expression Omnibus (GEO) database and GEO2R to screen out differentially expressed genes (DEGs). H. pylori was detected in 43.3% of the samples. Statistically significant differences were found for IL-6 (P=0.0001) and IL-6R (P=0.0005) genes among the three groups, regardless of the presence of H. pylori. Among patients with H. pylori infection, the IL-6 and IL-6R gene and protein expressions were significantly increased, highlighting IL-6 gene overexpression in patients with GC. No statistically significant differences were found for the rs1800795, rs1800796, and rs1800797 polymorphisms compared to IL-6 gene expression. The results indicated that the IL-6 polymorphisms do not influence its expression, but IL-6 and IL-6R expression seems to be altered by the presence of H. pylori.

Relationship of IL-1 and TNF-α polymorphisms with Helicobacter pylori in gastric diseases in a Brazilian population

It is well known that the risk of development of gastric cancer (GC) in Helicobacter pylori-infected patients depends on several factors. Thus, the aim of this study was to investigate the effect of proinflammatory cytokine gene polymorphisms for IL-1β, IL-1RN and TNF-α on the development of GC in a Brazilian population. A total of 202 biopsies obtained from Brazilian patients with chronic gastritis and GC were included in the study. Infection with H. pylori cagA+ was determined by the polymerase chain reaction (PCR) as previously described. IL-1β, IL-1RN and TNF-α polymorphism genotyping was performed by restriction fragment length polymorphism PCR. Associations between gene polymorphisms, clinical diseases and virulence markers were evaluated using either the χ² test or the Fisher exact test. Our results demonstrated that the IL-1β -511 C/C and IL-1β -511 C/T alleles were associated with chronic gastritis in H. pylori-positive patients (P = 0.04 and P = 0.05, respectively) and the IL-1β -511 C/C genotype was associated with GC (P = 0.03). The frequency of IL-1RN alleles from patients with chronic gastritis and GC indicated that there was no difference between the genotypes of the groups studied. Similar results were found for TNF-α -308 gene polymorphisms. Our results indicate that the IL-1β -511 C/C and C/T gene polymorphisms are associated with chronic gastritis and GC development in H. pylori-infected individuals.

Relación entre la integridad del CagPAI y los polimorfismos en el gen CagA con la severidad de la gastritis en pacientes infectados con H. pylori CagA positivo / The Relation between CagPAI integrity and the polymorphisms in the CagA gene with the severity of gastritis in patients infected with CagA-positive H. pylori

Objetivos: Evaluar la histopatología gástrica en pacientes colombianos con gastritis infectados con Helicobacter pylori CagA-positivo y su asociación a la integridad del islote de patogenicidad Cag (CagPAI) y el número de motivos EPIYA-C presentes en la proteína CagA. Métodos: Se incluyó a 31 individuos con diagnóstico de gastritis. A partir de biopsias gástricas se aisló H. pylori CagA-positivo y se caracterizó, mediante secuencia, la composición de motivos EPIYA. La histopatología fue evaluada según el sistema Sidney actualizado. Los genes CagA, CagT, CagE y Cag10 fueron genotipificados mediante PCR y electroforesis en agarosa. Resultados: En total, 24 aislamientos (el 77% de los casos) portaban CagPAI íntegro. De los aislamientos negativos para uno o más genes del CagPAI, 7 de ellos (22%) fueron considerados como portadores de un CagPAI defectuoso. No se observaron diferencias significativas en los promedios de densidad de H. pylori, el grado de inflamación crónica ni la presencia de atrofia glandular o de metaplasia intestinal entre aislamientos con el CagPAI íntegro, en comparación con aislamientos con el CagPAI defectuoso. Tampoco se observaron diferencias significativas en los parámetros histopatológicos entre los aislamientos con un motivo EPIYA-C o más de un motivo EPIYA-C, ni en antro ni en cuerpo, excepto para la infiltración por neutrófilos, que fue significativamente mayor en cuerpo en aislamientos con más de un motivo EPIYA-C (p=0,018). Conclusiones: No se halló asociación entre la diversidad en los factores de virulencia CagPAI y CagA de aislamientos colombianos, y los hallazgos histopatológicos en la gastritis, otros factores del hospedero o ambientales podrían afectar las características histopatológicas de la gastritis.

Objectives: To evaluate gastric histopathology in Colombian patients infected with CagA-positive Helicobacter pylori and its association with the integrity of Cag (CagPAI) pathogenicity island and the number of EPIYA-C motifs present in the CagA protein. Methods: Thirty-one (31) individuals diagnosed with gastritis were included in the study. Using gastric biopsies, CagA-positive H.pylori was isolated and EPIYA motif makeup was characterized by sequencing. Histopathology was evaluated with updated Sydney system. The CagA, CagT, CagE and Cag10 genes were genotyped using PCR and agarose electrophoresis. Results: A total of 24 isolates (77% of cases) carried a complete CagPAI. Among the negative isolates for one or more genes with CagPAI, 7 (22%) were considered to be carriers of a defective CagPAI. No significant differences were observed in H. pylori density averages, degree of chronic inflammation, presence of glandular atrophy or intestinal metaplasia between isolates with complete CagPAI and isolates with defective CagPAI. No significant differences were observed in the histopathological parameters between isolates with one EPIYAC motif and those with more than one EPIYA-C motif, neither in antrum nor in body, except for infiltration by neutrophils which was significantly greater in bodies with isolates with more than one EPIYA-C motif (p=0.018). Conclusions: No association was found between the diversity of virulence CagPAI and CagA factors in Colombian isolates and the histopathological findings in gastritis, or in other host or environmental factors that could affect the histopathological characteristics of gastritis.

Relationship between Helicobacter pylori Virulence Genes and Clinical Outcomes in Saudi Patients

Helicobacter pylori has been strongly associated with gastritis, gastric and duodenal ulcers, and it is a risk factor for gastric cancer. Two major virulence factors of H. pylori have been described: the cytotoxin-associated gene product (cagA) and the vacuolating toxin (vacA). Since considerable geographic diversity in the prevalence of H. pylori virulence factors has been reported, the aim of this work was to determine if there is a significant correlation between different H. pylori virulence genes (cagA and vacA) in 68 patients, from Saudi Arabia, and gastric clinical outcomes. H. pylor was recognized in cultures of gastric biopsies. vacA and cagA genes were detected by polymerase chain reaction (PCR). The cagA gene was obtained with 42 isolates (61.8%). The vacA s- and m- region genotypes were determined in all strains studied. Three genotypes were found: s1/m1 (28%), s1/m2 (40%) and s2/m2 (26%). The s2/m1 genotype was not found in this study. The relation of the presence of cagA and the development of cases to gastritis and ulcer was statistically significant (P < 0.05). The study showed a significant correlation between the vacA s1/m2 genotype and gastritis cases, and a significant correlation between vacA s1/m1 genotype and peptic ulcer cases. The results of this study might be used for the identification of high-risk patients who are infected by vacA s1/m1 genotype of H. pylori strains. In conclusion, H. pylori strains of vacA type s1 and the combination of s1/m1 were associated with peptic ulceration and the presence of cagA gene.

Study on Association between an H-RAS Gene Polymorphism and Gastric Cancer Development / 대한소화기학회지

BACKGROUND/AIMS: Oncogenic RAS gene mutations have been frequently observed in many tumor types, and their associations with various cancers were reported. This study was conducted to evaluate the association between H-RAS T81C polymorphism and gastric cancer development. METHODS: H-RAS T81C polymorphism was genotyped in 321 chronic gastritis (ChG) and 151 gastric cancer (GC) patients using GoldenGate(R) Assay kit. Logistic regression analysis adjusted for age and gender was performed to identify the differences of genotype and allele distributions between the each group. RESULTS: All ChG and GC patients were in Hardy-Weinberg equilibrium. When the frequencies of H-RAS T81C genotype in each group were compared, the homozygous type of major allele TT was more frequent in GC group (62.9%) than ChG group (57.3%), while the frequencies of heterozygous type TC and homozygous type of minor allele CC were higher in ChG group than GC group (39.3% vs. 33.8%, 3.4% vs. 3.3%, respectively). In the results of logistic regression analyses adjusted for age and gender, the odds ratios were 0.845 (0.604-1.182), 0.799 (0.556-1.147), 0.741 (0.493-1.114) and 1.094 (0.366-3.270) for allele, codominant, dominant and recessive models, respectively. However, significant difference was not observed between two groups in any models. CONCLUSIONS: H-RAS T81C polymorphism was not associated with gastric cancer development in a Korean population.

Study on Association between an H-RAS Gene Polymorphism and Gastric Cancer Development / 대한소화기학회지

No abstract available.

Global genome methylation status in gastritis lesion in comparison with normal adjacent tissue and its relationship with clinicopathologic findings

To determine the role of global genome methylation in gastritis lesion and its relation with clinicopathologic finding. The study was conducted on 44 gastritis and normal adjacent specimens using a technique composed of restriction enzyme digestion and pyrosequencing known as LUMA [LUminometric Methylation Assay]. At first, DNA extracted from gastritis lesion and normal tissue was digested with HpaII [sensitive to methylation in recognition site] and MspI [insensitive]. These enzymes leave an overhang after cutting which are then filled in a polymerase extension assay with stepwise addition of dNTPs using pyrosequencing. The comparison of the height of picks obtained form both enzymes provides the possibility to evaluate and compare global genome methylation level of normal and gastritis tissues. If the target site is fully methylated, the HpaII/MspI will approach toward zero .If not, this ratio will go around one. In the other conditions the ratio varies between 0-1. According to our findings, gastritis tissue was significantly more hypomethylated [p = 0.04] than the nornal tissue and Global genome methylation had no correlation with sex, age, microsatellite instability [MSI] and gastritis severity. Global DNA hypomethylation occurs in the gastritis lesion. Presumably the process of hypomethylation keeps falling in the next steps leading to gastric cancer

[Study of the CagA gene prevalence in helicobacter pylori strains isolated from patients with upper gastrointestinal disorders in Iran]

Helicobacter pylori commonly is associated with gastritis: but only sometimes it causes clinically significant diseases such as gastric and duodenal ulcer. The development of disease depends on the virulence of the infecting H. pylori strain, the susceptibility of the host, and environment co-factors. The cytotoxin associated protein encoded by cagA gene is an important virulence factor that is produced by some H. pylori strains, and has been used as virulence marker in some populations. The aim of the study was to examine the prevalence of cagA gene in the isolated strains of H. pylori from patients with dyspeptic disease and to investigate the association of cagA gene and the severity of H. pylori related diseases in Iran. In this study, biopsy specimens were obtained from the antrum of 180 patients. After isolation of H. pylori and its DNA by standard methods, polymerase chain reaction [PCR] technique was used for detection of cagA bacterial gene. 92 out of the 180 patients had H. pylori strains. 70% were cagA gene positive. All patients with peptic ulcer [100%] and 44 out of 72 [61%] patients with non-ulcer dyspepsia were cagA positive [p<0.01]. There was significant difference in frequency of cagA gene in peptic ulcer disease and non-ulcer dyspepsia [p<0.01]. It showed that the risk of PUD in patients with cagA+ H. pylori infection may be higher than in those with cagA- H. pylori infection

Alteraciones genéticas en gastritis crónica: Estudio de inestabilidad microsatelital y pérdida de la heterocigocidad / Genetic changes in chronic gastritis: study of microsatellite instability and loss of heterozygosity

Background: Multifocal chronic gastritis, associated to intestinal metaplasia, is considered a preneoplastic lesion, closely associated to intestinal type gastric cancer. Aim: To study the frequency of microsatellite instability (MSI) and loss of heterozygosity (LOH) in areas of chronic gastritis and intestinal metaplasia in gastric biopsies of patients without cancer. Material and methods: Gastric biopsy samples from 34 patients without cancer (22 with multifocal atrophic gastritis and 12 with diffuse antral gastritis), were studied. Glands from areas of chonic gastritis and intestinal metaplasia and lymphocytes, were collected using laser microdissection of paraffin embedded samples. The analysis of 15 mono and dinucleotide microsatellites was used to assess LOH and MSI. Results: LOH and MSI were found in some of the markers in 55% (12/22) and 59% (13/22) of cases with intestinal metaplasia, respectively. Only one of 12 areas with diffuse atrophic gastritis had MSI and a different area had LOH (p <0.05 or less, when compared with areas of multifocal atrophic gastritis). Three areas of normal epithelium in patients with multifocal atrophic gastritis, also had alterations. Most of these alterations were concordant with adjacent areas with intestinal metaplasia. Conclusions: LOH and MSI was found in areas of intestinal metaplasia in more than half of the studied cases and in few areas of atrophic gastritis without intestinal metaplasia. These findings suggest that genotypic alterations may precede phenotypic modifications and that intestinal metaplasia is a preneoplastic lesion (Rev Méd Chile 2003; 131: 1365-74).

Relevance of vacA Genotypes of Helicobacter pylori to cagA Status and Its Clinical Outcome

BACKGROUND: Determination of vacA mosaicism may be important because specific Helicobacter pylori vacA genotype can be used to predict different clinical outcome. The aim of this study was to assess the relationship of vacA genotypes of Helicobacter pylori to cagA status and its development of peptic ulcer diseases in Korean patients. METHODS: Gastric biopsy specimens were obtained from 53 patients with gastric ulcer(GU), 57 with duodenal ulcer (DU) and 26 with chronic gastritis(CG) patients; all patients were infected with Helicobacter pylori. Bacterial mRNAs in the gastric mucosa were amplified by RT-PCR, using synthetic oligonucleotide primers specific for the vacA and the cagA gene. Patients with vacA s1 subtype were further examined to determine whether they had s1a or s1b subtype. RESULTS: There was no correlation in frequency of vacA s1 and/or s1a genotype between CG and either GU or DU, as the vacA s1 and s1a/m1 were present in the majority of strains independent of clinical status(s1 ; 100.0% versus 94.3 % or 93.0 % and s1a/m1 ; 76.9% versus 62.3% or 64.9%, res pectively). Likewise, there was no difference in the prevalence of the cagA gene between CG and either GU or DU patients (92.3% versus 90.6% or 98.2%, respectively). In addition, the cagA-negative status did not predict the presence of vacA s2 genotype. CONCLUSION: These results strongly suggest that either cagA or vacA s1 and/or s1a is not proved to be a useful marker to distinguish disease-specific Helicobacter pylori strains for the development of peptic ulcer diseases in Korean patients.