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1.
Mol Cell Proteomics ; 18(2): 352-371, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30455363

RESUMO

Helicobacter pylori is the strongest risk factor for gastric cancer. Initial interactions between H. pylori and its host originate at the microbial-gastric epithelial cell interface, and contact between H. pylori and gastric epithelium activates signaling pathways that drive oncogenesis. One microbial constituent that increases gastric cancer risk is the cag pathogenicity island, which encodes a type IV secretion system that translocates the effector protein, CagA, into host cells. We previously demonstrated that infection of Mongolian gerbils with a carcinogenic cag+H. pylori strain, 7.13, recapitulates many features of H. pylori-induced gastric cancer in humans. Therefore, we sought to define gastric proteomic changes induced by H. pylori that are critical for initiation of the gastric carcinogenic cascade. Gastric cell scrapings were harvested from H. pylori-infected and uninfected gerbils for quantitative proteomic analyses using isobaric tags for relative and absolute quantitation (iTRAQ). Quantitative proteomic analysis of samples from two biological replicate experiments quantified a total of 2764 proteins, 166 of which were significantly altered in abundance by H. pylori infection. Pathway mapping identified significantly altered inflammatory and cancer-signaling pathways that included Rab/Ras signaling proteins. Consistent with the iTRAQ results, RABEP2 and G3BP2 were significantly up-regulated in vitro, ex vivo in primary human gastric monolayers, and in vivo in gerbil gastric epithelium following infection with H. pylori strain 7.13 in a cag-dependent manner. Within human stomachs, RABEP2 and G3BP2 expression in gastric epithelium increased in parallel with the severity of premalignant and malignant lesions and was significantly elevated in intestinal metaplasia and dysplasia, as well as gastric adenocarcinoma, compared with gastritis alone. These results indicate that carcinogenic strains of H. pylori induce dramatic and specific changes within the gastric proteome in vivo and that a subset of altered proteins within pathways with oncogenic potential may facilitate the progression of gastric carcinogenesis in humans.


Assuntos
Proteínas de Transporte/metabolismo , Infecções por Helicobacter/complicações , Helicobacter pylori/patogenicidade , Neoplasias Gástricas/microbiologia , Proteínas de Transporte Vesicular/metabolismo , Proteínas Adaptadoras de Transdução de Sinal , Animais , Linhagem Celular , Modelos Animais de Doenças , Regulação Neoplásica da Expressão Gênica , Gerbillinae , Infecções por Helicobacter/microbiologia , Humanos , Mucosa Intestinal/metabolismo , Mucosa Intestinal/microbiologia , Masculino , Mapas de Interação de Proteínas , Proteômica , Proteínas de Ligação a RNA , Neoplasias Gástricas/metabolismo , Regulação para Cima
2.
Oncogene ; 37(37): 5054-5065, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-29849123

RESUMO

Infection with Helicobacter pylori is one of the strongest risk factors for development of gastric cancer. Although these bacteria infect approximately half of the world's population, only a small fraction of infected individuals develops gastric malignancies. Interactions between host and bacterial virulence factors are complex and interrelated, making it difficult to elucidate specific processes associated with H. pylori-induced tumorigenesis. In this study, we found that H. pylori inhibits p14ARF tumor suppressor by inducing its degradation. This effect was found to be strain-specific. Downregulation of p14ARF induced by H. pylori leads to inhibition of autophagy in a p53-independent manner in infected cells. We identified TRIP12 protein as E3 ubiquitin ligase that is upregulated by H. pylori, inducing ubiquitination and subsequent degradation of p14ARF protein. Using isogenic H. pylori mutants, we found that induction of TRIP12 is mediated by bacterial virulence factor CagA. Increased expression of TRIP12 protein was found in infected gastric epithelial cells in vitro and human gastric mucosa of H. pylori-infected individuals. In conclusion, our data demonstrate a new mechanism of ARF inhibition that may affect host-bacteria interactions and facilitate tumorigenic transformation in the stomach.


Assuntos
Autofagia/fisiologia , Células Epiteliais/metabolismo , Infecções por Helicobacter/metabolismo , Helicobacter pylori/patogenicidade , Proteína Supressora de Tumor p14ARF/metabolismo , Antígenos de Bactérias/metabolismo , Proteínas de Bactérias/metabolismo , Linhagem Celular Tumoral , Regulação para Baixo/fisiologia , Mucosa Gástrica/metabolismo , Mucosa Gástrica/patologia , Células HCT116 , Infecções por Helicobacter/microbiologia , Helicobacter pylori/metabolismo , Humanos , Transdução de Sinais/fisiologia , Estômago/patologia , Neoplasias Gástricas/metabolismo , Neoplasias Gástricas/patologia , Proteína Supressora de Tumor p53/metabolismo , Ubiquitina-Proteína Ligases/metabolismo , Regulação para Cima/fisiologia , Fatores de Virulência/metabolismo
3.
Cancer Cell ; 33(4): 721-735.e8, 2018 04 09.
Artigo em Inglês | MEDLINE | ID: mdl-29622466

RESUMO

We analyzed 921 adenocarcinomas of the esophagus, stomach, colon, and rectum to examine shared and distinguishing molecular characteristics of gastrointestinal tract adenocarcinomas (GIACs). Hypermutated tumors were distinct regardless of cancer type and comprised those enriched for insertions/deletions, representing microsatellite instability cases with epigenetic silencing of MLH1 in the context of CpG island methylator phenotype, plus tumors with elevated single-nucleotide variants associated with mutations in POLE. Tumors with chromosomal instability were diverse, with gastroesophageal adenocarcinomas harboring fragmented genomes associated with genomic doubling and distinct mutational signatures. We identified a group of tumors in the colon and rectum lacking hypermutation and aneuploidy termed genome stable and enriched in DNA hypermethylation and mutations in KRAS, SOX9, and PCBP1.


Assuntos
Adenocarcinoma/genética , Instabilidade Cromossômica , Metilação de DNA , DNA Polimerase II/genética , Neoplasias Gastrointestinais/genética , Proteína 1 Homóloga a MutL/genética , Proteínas de Ligação a Poli-ADP-Ribose/genética , Adenocarcinoma/classificação , Aneuploidia , Proteínas de Ligação a DNA , Epigênese Genética , Feminino , Neoplasias Gastrointestinais/classificação , Redes Reguladoras de Genes , Ribonucleoproteínas Nucleares Heterogêneas/genética , Humanos , Masculino , Instabilidade de Microssatélites , Mutação , Polimorfismo de Nucleotídeo Único , Proteínas Proto-Oncogênicas p21(ras)/genética , Proteínas de Ligação a RNA , Fatores de Transcrição SOX9/genética
4.
Cell ; 173(2): 291-304.e6, 2018 04 05.
Artigo em Inglês | MEDLINE | ID: mdl-29625048

RESUMO

We conducted comprehensive integrative molecular analyses of the complete set of tumors in The Cancer Genome Atlas (TCGA), consisting of approximately 10,000 specimens and representing 33 types of cancer. We performed molecular clustering using data on chromosome-arm-level aneuploidy, DNA hypermethylation, mRNA, and miRNA expression levels and reverse-phase protein arrays, of which all, except for aneuploidy, revealed clustering primarily organized by histology, tissue type, or anatomic origin. The influence of cell type was evident in DNA-methylation-based clustering, even after excluding sites with known preexisting tissue-type-specific methylation. Integrative clustering further emphasized the dominant role of cell-of-origin patterns. Molecular similarities among histologically or anatomically related cancer types provide a basis for focused pan-cancer analyses, such as pan-gastrointestinal, pan-gynecological, pan-kidney, and pan-squamous cancers, and those related by stemness features, which in turn may inform strategies for future therapeutic development.


Assuntos
Neoplasias/patologia , Aneuploidia , Cromossomos/genética , Análise por Conglomerados , Ilhas de CpG , Metilação de DNA , Bases de Dados Factuais , Humanos , MicroRNAs/metabolismo , Mutação , Proteínas de Neoplasias/genética , Proteínas de Neoplasias/metabolismo , Neoplasias/genética , RNA Mensageiro/metabolismo
5.
Gut ; 67(7): 1239-1246, 2018 07.
Artigo em Inglês | MEDLINE | ID: mdl-28647684

RESUMO

OBJECTIVE: To evaluate the long-term effect of cumulative time exposed to Helicobacter pylori infection on the progression of gastric lesions. DESIGN: 795 adults with precancerous gastric lesions were randomised to receive anti-H. pylori treatment at baseline. Gastric biopsies were obtained at baseline and at 3, 6, 12 and 16 years. A total of 456 individuals attended the 16-year visit. Cumulative time of H. pylori exposure was calculated as the number of years infected during follow-up. Multivariable logistic regression models were used to estimate the risk of progression to a more advanced diagnosis (versus no change/regression) as well as gastric cancer risk by intestinal metaplasia (IM) subtype. For a more detailed analysis of progression, we also used a histopathology score assessing both severity and extension of the gastric lesions (range 1-6). The score difference between baseline and 16 years was modelled by generalised linear models. RESULTS: Individuals who were continuously infected with H. pylori for 16 years had a higher probability of progression to a more advanced diagnosis than those who cleared the infection and remained negative after baseline (p=0.001). Incomplete-type IM was associated with higher risk of progression to cancer than complete-type (OR, 11.3; 95% CI 1.4 to 91.4). The average histopathology score increased by 0.20 units/year (95% CI 0.12 to 0.28) among individuals continuously infected with H. pylori. The effect of cumulative time of infection on progression in the histopathology score was significantly higher for individuals with atrophy (without IM) than for individuals with IM (p<0.001). CONCLUSIONS: Long-term exposure to H. pylori infection was associated with progression of precancerous lesions. Individuals infected with H. pylori with these lesions may benefit from eradication, particularly those with atrophic gastritis without IM. Incomplete-type IM may be a useful marker for the identification of individuals at higher risk for cancer.


Assuntos
Antibacterianos/uso terapêutico , Infecções por Helicobacter/tratamento farmacológico , Infecções por Helicobacter/patologia , Lesões Pré-Cancerosas/microbiologia , Lesões Pré-Cancerosas/patologia , Neoplasias Gástricas/microbiologia , Adulto , Idoso , Progressão da Doença , Esquema de Medicação , Feminino , Seguimentos , Infecções por Helicobacter/complicações , Helicobacter pylori , Humanos , Masculino , Metaplasia , Pessoa de Meia-Idade , Fatores de Risco , Neoplasias Gástricas/patologia
6.
Genome Announc ; 5(15)2017 Apr 13.
Artigo em Inglês | MEDLINE | ID: mdl-28408665

RESUMO

We present here the draft genomes of 13 Helicobacter pylori strains isolated from Colombian residents on the Pacific coast (n = 6) and in the Andes mountains (n = 7), locations that differ in gastric cancer risk. These 13 strains were obtained from individuals with diagnosed gastric lesions.

7.
Oncotarget ; 8(29): 47076-47089, 2017 Jul 18.
Artigo em Inglês | MEDLINE | ID: mdl-28423364

RESUMO

Helicobacter pylori infection triggers a cascade of inflammatory stages that may lead to the appearance of non-atrophic gastritis, multifocal atrophic, intestinal metaplasia, dysplasia, and cancer. Deleted in malignant brain tumors 1 (DMBT1) belongs to the group of secreted scavenger receptor cysteine-rich proteins and is considered to be involved in host defense by binding to pathogens. Initial studies showed its deletion and loss of expression in a variety of tumors but the role of this gene in tumor development is not completely understood. Here, we examined the role of DMBT1 in gastric precancerous lesions in Caucasian, African American and Hispanic individuals as well as in the development of gastric pathology in a mouse model of H. pylori infection. We found that in 3 different populations, mucosal DMBT1 expression was significantly increased (2.5 fold) in individuals with dysplasia compared to multifocal atrophic gastritis without intestinal metaplasia; the increase was also observed in individuals with advanced gastritis and positive H. pylori infection. In our animal model, H. pylori infection of Dmbt1-/- mice resulted in significantly higher levels of gastritis, more extensive mucous metaplasia and reduced Il33 expression levels in the gastric mucosa compared to H. pylori-infected wild type mice. Our data in the animal model suggest that in response to H. pylori infection DMBT1 may mediate mucosal protection reducing the risk of developing gastric precancerous lesions. However, the increased expression in human gastric precancerous lesions points to a more complex role of DMBT1 in gastric carcinogenesis.


Assuntos
Regulação Neoplásica da Expressão Gênica , Lesões Pré-Cancerosas/genética , Receptores de Superfície Celular/genética , Neoplasias Gástricas/genética , Neoplasias Gástricas/patologia , Animais , Proteínas de Ligação ao Cálcio , Proteínas de Ligação a DNA , Modelos Animais de Doenças , Etnicidade/genética , Mucosa Gástrica/metabolismo , Mucosa Gástrica/patologia , Perfilação da Expressão Gênica , Estudos de Associação Genética , Infecções por Helicobacter/complicações , Humanos , Camundongos , Camundongos Knockout , Estadiamento de Neoplasias , Proteínas Supressoras de Tumor
9.
Hum Genet ; 135(8): 895-906, 2016 08.
Artigo em Inglês | MEDLINE | ID: mdl-27225266

RESUMO

Gastric cancer incidence varies considerably among populations, even those with comparable rates of Helicobacter pylori infection. To test the hypothesis that genetic variation plays a role in gastric disease, we assessed the relationship between genotypes and gastric histopathology in a Colombian study population, using a genotyping array of immune-related single nucleotide polymorphisms (SNPs). Two synonymous SNPs (rs6061243 and rs6587239) were associated with progression of premalignant gastric lesions in a dominant-effects model after correction for multiple comparisons (p = 2.63E-07 and p = 7.97E-07, respectively); effect sizes were ß = -0.863 and ß = -0.815, respectively, where ß is an estimate of effect on histopathology scores, which ranged from 1 (normal) to 5 (dysplasia). In our replication cohort, a second Colombian population, both SNPs were associated with histopathology when additively modeled (ß = -0.256, 95 % CI = -0.47, -0.039; and ß = -0.239, 95 % CI = -0.45, -0.024), and rs6587239 was significantly associated in a dominant-effects model (ß = -0.330, 95 % CI = -0.66, 0.00). Because promoter methylation of GATA5 has previously been associated with gastric cancer, we also tested for the association of methylation status with more advanced histopathology scores in our samples and found a significant relationship (p = 0.001). A multivariate regression model revealed that the effects of both the promoter methylation and the exonic SNPs in GATA5 were independent. A SNP-by-methylation interaction term was also significant. This interaction between GATA5 variants and GATA5 promoter methylation indicates that the association of either factor with gastric disease progression is modified by the other.


Assuntos
Metilação de DNA/genética , Epigenômica , Fator de Transcrição GATA5/genética , Infecções por Helicobacter/genética , Neoplasias Gástricas/genética , Adulto , Feminino , Estudos de Associação Genética , Genótipo , Infecções por Helicobacter/microbiologia , Infecções por Helicobacter/patologia , Helicobacter pylori/patogenicidade , Humanos , Masculino , Pessoa de Meia-Idade , Polimorfismo de Nucleotídeo Único , Regiões Promotoras Genéticas , Fatores de Risco , Neoplasias Gástricas/microbiologia , Neoplasias Gástricas/patologia
10.
Cancer Lett ; 371(1): 90-8, 2016 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-26639196

RESUMO

Infection with Helicobacter pylori (H. pylori) leads to inflammatory events that can promote gastric cancer development. Immune cells transition from the circulation into the infected mucosa through the interaction of their receptors and ligands in the endothelial compartment. CD44 expression is increased in advanced gastric lesions. However, the association of this molecule with the progression of these lesions over time has not been investigated. In addition, there is a lack of understanding of the CD44-dependent cellular processes that lead to gastritis, and possibly to gastric cancer. Here we studied H. pylori-positive subjects with gastric lesions that ranged from multifocal atrophic gastritis to dysplasia to determine gene expression changes associated with disease progression over a period of 6 years. We report that CD44 expression is significantly increased in individuals whose gastric lesions progressed along the gastric precancerous cascade. We also show that CD44-/- mice develop less severe and less extensive H. pylori-induced metaplasia, and show fewer infiltrating Gr1+ cells compared to wild type mice. We present data suggesting that CD44 is associated with disease progression. Mechanisms associated with these effects include induction of interferon gamma responses.


Assuntos
Mucosa Gástrica/metabolismo , Gastrite Atrófica/metabolismo , Infecções por Helicobacter/metabolismo , Helicobacter pylori/patogenicidade , Receptores de Hialuronatos/metabolismo , Lesões Pré-Cancerosas/metabolismo , Neoplasias Gástricas/metabolismo , Animais , Antígenos Ly/metabolismo , Células Cultivadas , Quimiotaxia de Leucócito , Modelos Animais de Doenças , Progressão da Doença , Feminino , Mucosa Gástrica/imunologia , Mucosa Gástrica/microbiologia , Mucosa Gástrica/patologia , Gastrite Atrófica/diagnóstico , Gastrite Atrófica/genética , Gastrite Atrófica/imunologia , Gastrite Atrófica/microbiologia , Infecções por Helicobacter/diagnóstico , Infecções por Helicobacter/genética , Infecções por Helicobacter/imunologia , Infecções por Helicobacter/microbiologia , Helicobacter pylori/imunologia , Humanos , Receptores de Hialuronatos/genética , Receptores de Hialuronatos/imunologia , Interferon gama/metabolismo , Macrófagos Peritoneais/imunologia , Macrófagos Peritoneais/metabolismo , Camundongos Knockout , Infiltração de Neutrófilos , Neutrófilos/imunologia , Neutrófilos/metabolismo , Lesões Pré-Cancerosas/diagnóstico , Lesões Pré-Cancerosas/genética , Lesões Pré-Cancerosas/imunologia , Lesões Pré-Cancerosas/microbiologia , Transdução de Sinais , Neoplasias Gástricas/diagnóstico , Neoplasias Gástricas/genética , Neoplasias Gástricas/imunologia , Neoplasias Gástricas/microbiologia , Fatores de Tempo
11.
Cancer Epidemiol Biomarkers Prev ; 24(10): 1607-13, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26269563

RESUMO

BACKGROUND: Development of the intestinal subtype of gastric adenocarcinoma is marked by a progression of histopathologic lesions. Residents of the Andean regions of Colombia are at high risk for gastric cancer. METHODS: A cohort of 976 Colombian subjects was followed over 16 years examining effects of Helicobacter pylori eradication and treatment with antioxidants on progression of lesions. We performed methylation analysis of DNA from baseline antral biopsies from 104 subjects for whom follow-up data were available for at least 12 years. Methylation was quantitated for AMPH, CDKN2A, CDH1, EN1, EMX1, NKX6-1, PCDH10, RPRM, RSPO2, SORCS3, ZIC1, and ZNF610 genes, using Pyrosequencing. RESULTS: Levels of DNA methylation were associated with baseline diagnosis for AMPH, EMX1, RPRM, RSPO2, SORCS3, and ZNF610. After adjusting for baseline diagnosis and H. pylori infection, methylation levels of AMPH, PCDH10, RSPO2, and ZNF610 had progression coefficients that increased and P values that decreased over 6, 12, and 16 years. Methylation for SORCS3 was associated with progression at all 3 time points but without the continual strengthening of the effect. Scores for mononuclear leukocytes, polymorphonuclear leukocytes, or intraepithelial lymphocytes were unrelated to progression. CONCLUSIONS: Methylation levels of AMPH, PCDH10, RSPO2, SORCS3, and ZNF610 predict progression of gastric lesions independent of the effect of duration of H. pylori infection, baseline diagnosis, gender of the patient, or scores for mononuclear leukocytes, polymorphonuclear leukocytes, or intraepithelial lymphocytes. IMPACT: DNA methylation levels in AMPH, PCDH10, RSPO2, SORCS3, and ZNF610 may contribute to identification of persons with gastric lesions likely to progress.


Assuntos
Antibacterianos/uso terapêutico , Biomarcadores Tumorais/genética , DNA de Neoplasias/genética , Previsões , Infecções por Helicobacter/tratamento farmacológico , Lesões Pré-Cancerosas/genética , Neoplasias Gástricas/genética , Adenocarcinoma/diagnóstico , Adenocarcinoma/genética , Adenocarcinoma/prevenção & controle , Adulto , Biomarcadores Tumorais/metabolismo , Quimioprevenção/métodos , Metilação de DNA , Progressão da Doença , Método Duplo-Cego , Endoscopia Gastrointestinal , Feminino , Mucosa Gástrica/metabolismo , Mucosa Gástrica/microbiologia , Mucosa Gástrica/patologia , Infecções por Helicobacter/complicações , Infecções por Helicobacter/microbiologia , Helicobacter pylori/isolamento & purificação , Humanos , Masculino , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase , Neoplasias Gástricas/diagnóstico , Neoplasias Gástricas/prevenção & controle
12.
Front Genet ; 5: 290, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25202324

RESUMO

A major goal in infectious disease research is to identify the human and pathogenic genetic variants that explain differences in microbial pathogenesis. However, neither pathogenic strain nor human genetic variation in isolation has proven adequate to explain the heterogeneity of disease pathology. We suggest that disrupted co-evolution between a pathogen and its human host can explain variation in disease outcomes, and that genome-by-genome interactions should therefore be incorporated into genetic models of disease caused by infectious agents. Genetic epidemiological studies that fail to take both the pathogen and host into account can lead to false and misleading conclusions about disease etiology. We discuss our model in the context of three pathogens, Helicobacter pylori, Mycobacterium tuberculosis and human papillomavirus, and generalize the conditions under which it may be applicable.

13.
Proc Natl Acad Sci U S A ; 111(4): 1455-60, 2014 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-24474772

RESUMO

Helicobacter pylori is the principal cause of gastric cancer, the second leading cause of cancer mortality worldwide. However, H. pylori prevalence generally does not predict cancer incidence. To determine whether coevolution between host and pathogen influences disease risk, we examined the association between the severity of gastric lesions and patterns of genomic variation in matched human and H. pylori samples. Patients were recruited from two geographically distinct Colombian populations with significantly different incidences of gastric cancer, but virtually identical prevalence of H. pylori infection. All H. pylori isolates contained the genetic signatures of multiple ancestries, with an ancestral African cluster predominating in a low-risk, coastal population and a European cluster in a high-risk, mountain population. The human ancestry of the biopsied individuals also varied with geography, with mostly African ancestry in the coastal region (58%), and mostly Amerindian ancestry in the mountain region (67%). The interaction between the host and pathogen ancestries completely accounted for the difference in the severity of gastric lesions in the two regions of Colombia. In particular, African H. pylori ancestry was relatively benign in humans of African ancestry but was deleterious in individuals with substantial Amerindian ancestry. Thus, coevolution likely modulated disease risk, and the disruption of coevolved human and H. pylori genomes can explain the high incidence of gastric disease in the mountain population.


Assuntos
Suscetibilidade a Doenças , Evolução Molecular , Infecções por Helicobacter/microbiologia , Helicobacter pylori/genética , Gastropatias/microbiologia , Adulto , Idoso , Infecções por Helicobacter/complicações , Humanos , Pessoa de Meia-Idade
14.
Epigenetics ; 8(11): 1153-61, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-24128875

RESUMO

DNA methylation changes are known to occur in gastric cancers and in premalignant lesions of the gastric mucosae. In order to examine variables associated with methylation levels, we quantitatively evaluated DNA methylation in tumors, non-tumor gastric mucosae, and in gastric biopsies at promoters of 5 genes with methylation alterations that discriminate gastric cancers from non-tumor epithelia (EN1, PCDH10, RSPO2, ZIC1, and ZNF610). Among Colombian subjects at high and low risk for gastric cancer, biopsies from subjects from the high-risk region had significantly higher levels of methylation at these 5 genes than samples from subjects in the low risk region (p ≤ 0.003). When results were stratified by Helicobacter pylori infection status, infection with a cagA positive, vacA s1m1 strain was significantly associated with highest methylation levels, compared with other strains (p = 0.024 to 0.001). More severe gastric inflammation and more advanced precancerous lesions were also associated with higher levels of DNA methylation (p ≤ 0.001). In a multivariate model, location of residence of the subject and the presence of cagA and vacA s1m1 in the H. pylori strain were independent variables associated with higher methylation in all 5 genes. High levels of mononuclear cell infiltration were significantly related to methylation in PCDH10, RSPO2, and ZIC1 genes. These results indicate that for these genes, levels of methylation in precancerous lesions are related to H. pylori virulence, geographic region and measures of chronic inflammation. These genes seem predisposed to sustain significant quantitative changes in DNA methylation at early stages of the gastric precancerous process.


Assuntos
Metilação de DNA , Mucosa Gástrica/metabolismo , Infecções por Helicobacter/microbiologia , Helicobacter pylori/patogenicidade , Leucócitos Mononucleares/fisiologia , Adenocarcinoma/imunologia , Adenocarcinoma/metabolismo , Adenocarcinoma/microbiologia , Adenocarcinoma/patologia , Adulto , Mucosa Gástrica/imunologia , Mucosa Gástrica/patologia , Infecções por Helicobacter/imunologia , Infecções por Helicobacter/metabolismo , Infecções por Helicobacter/patologia , Helicobacter pylori/genética , Humanos , Leucócitos Mononucleares/imunologia , Pessoa de Meia-Idade , Neoplasias Gástricas/imunologia , Neoplasias Gástricas/metabolismo , Neoplasias Gástricas/microbiologia , Neoplasias Gástricas/patologia , Virulência
15.
J Pediatr Gastroenterol Nutr ; 57(2): 192-6, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-23880626

RESUMO

BACKGROUND AND OBJECTIVE: Gastric infection with Helicobacter pylori (H pylori), a strong risk factor for gastric cancer, is highly prevalent in children residing in the Colombian Andes. We aimed to validate the use of the Entero-test to culture and genotype H pylori strains from asymptomatic Colombian children. METHODS: Children (ages 10-15 years, n = 110, 80 of which were H pylori positive by the urea breath test [UBT]) were subjected to the Entero-test, and strings were cultured and/or used for DNA extraction for polymerase chain reaction (PCR). These children had been treated for H pylori in 2007. A second population of children (ages 10-15 years, n = 95),which had not been previously treated, was also subjected to the Entero-test. RESULTS: Of UBT-positive children in the treated group, 29 of 80 (36%) Entero-test samples were H pylori culture positive; 29 additional string extracts were tested by PCR for the H pylori virulence factors cagA and vacA. PCR from cultures and extracts yielded a sensitivity of 74% and specificity of 87%. In the untreated group, 16 of 94 UBT-positive children (17%) produced Entero-tests that were culture positive. Fifty-eight of 94 (62%) string extracts were PCR positive for cagA and/or vacA. In previously treated children, H pylori strains were more often the less virulent vacA s2 (P = 0.001), m2 (P = 0.006), and i2 genotypes (P = 0.039). CONCLUSIONS: The Entero-test may be used as a noninvasive test to detect H pylori in asymptomatic children residing in high-risk areas for gastric cancer. Treatment of H pylori in children was associated with less virulent genotypes.


Assuntos
Antígenos de Bactérias/genética , Proteínas de Bactérias/genética , DNA Bacteriano , Infecções por Helicobacter/microbiologia , Helicobacter pylori/genética , Reação em Cadeia da Polimerase/métodos , Neoplasias Gástricas/microbiologia , Fatores de Virulência/genética , Técnicas de Tipagem Bacteriana , Testes Respiratórios , Criança , Colômbia/epidemiologia , Doenças Endêmicas , Feminino , Genótipo , Infecções por Helicobacter/epidemiologia , Helicobacter pylori/patogenicidade , Humanos , Masculino , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
16.
Cancer Prev Res (Phila) ; 6(4): 253-6, 2013 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-23559450

RESUMO

Niwa and colleagues report in this issue that treatment with the DNA demethylation agent 5-aza-2'-deoxycytidine decreases the incidence of gastric cancers in an animal model of Helicobacter pylori-promoted gastric cancer. This provocative study underscores the importance of changes in DNA methylation that contribute to the origin of inflammation-related cancers. The findings also raise the exciting possibility of cancer prevention by altering DNA methylation events early during tumorigenesis.


Assuntos
Adenocarcinoma/microbiologia , Adenocarcinoma/prevenção & controle , Azacitidina/análogos & derivados , DNA-Citosina Metilases/antagonistas & inibidores , Infecções por Helicobacter/complicações , Helicobacter pylori/fisiologia , Neoplasias Gástricas/microbiologia , Neoplasias Gástricas/prevenção & controle , Animais , Azacitidina/uso terapêutico , Decitabina , Masculino
17.
PLoS One ; 7(10): e46214, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-23071548

RESUMO

Gastric cancer remains the second leading cause of cancer-related death in the world. H. pylori infection, a major risk factor for gastric cancer, generates high levels of reactive oxygen species (ROS). Glutathione peroxidase 3 (GPX3), a plasma GPX member and a major scavenger of ROS, catalyzes the reduction of hydrogen peroxide and lipid peroxides by reduced glutathione. To study the expression and gene regulation of GPX3, we examined GPX3 gene expression in 9 gastric cancer cell lines, 108 primary gastric cancer samples and 45 normal gastric mucosa adjacent to cancers using quantitative real-time RT-PCR. Downregulation or silencing of GPX3 was detected in 8 of 9 cancer cell lines, 83% (90/108) gastric cancers samples, as compared to non-tumor adjacent normal gastric samples (P<0.0001). Examination of GPX3 promoter demonstrated DNA hypermethylation (≥ 10% methylation level determined by Bisulfite Pyrosequencing) in 6 of 9 cancer cell lines and 60% of gastric cancer samples (P = 0.007). We also detected a significant loss of DNA copy number of GPX3 in gastric cancers (P<0.001). Treatment of SNU1 and MKN28 cells with 5-Aza-2' Deoxycytidine restored the GPX3 gene expression with a significant demethylation of GPX3 promoter. The downregulation of GPX3 expression and GPX3 promoter hypermethylation were significantly associated with gastric cancer lymph node metastasis (P = 0.018 and P = 0.029, respectively). We also observed downregulation, DNA copy number losses, and promoter hypermethylation of GPX3 in approximately one-third of tumor-adjacent normal gastric tissue samples, suggesting the presence of a field defect in areas near tumor samples. Reconstitution of GPX3 in AGS cells reduced the capacity of cell migration, as measured by scratch wound healing assay. Taken together, the dysfunction of GPX3 in gastric cancer is mediated by genetic and epigenetic alterations, suggesting impairment of mechanisms that regulate ROS and its possible involvement in gastric tumorigenesis and metastasis.


Assuntos
Metilação de DNA , Inativação Gênica , Glutationa Peroxidase/genética , Metástase Linfática/genética , Neoplasias Gástricas/patologia , Azacitidina/análogos & derivados , Azacitidina/farmacologia , Estudos de Casos e Controles , Linhagem Celular Tumoral , Decitabina , Imunofluorescência , Regulação Enzimológica da Expressão Gênica/efeitos dos fármacos , Humanos , Regiões Promotoras Genéticas , RNA Mensageiro/genética , Reação em Cadeia da Polimerase em Tempo Real , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Neoplasias Gástricas/enzimologia , Neoplasias Gástricas/genética
18.
Helicobacter ; 17(2): 96-106, 2012 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-22404439

RESUMO

BACKGROUND: Helicobacter pylori infection is usually acquired in childhood, but little is known about its natural history in asymptomatic children, primarily due to the paucity of non-invasive diagnostic methods. H. pylori strains harboring cagA and specific alleles of hopQ and vacA are associated with increased risk for gastric cancer. Many studies of H. pylori virulence markers in children have the bias that symptomatic subjects are selected for endoscopy, and these children may harbor the most virulent strains. Our aim is to genotype cagA, hopQ, and vacA alleles in stool DNA samples of healthy Colombian children residing in an area with high incidence of gastric cancer, to avoid selection bias resulting from endoscopy. METHODS: H. pylori status of 86 asymptomatic children was assessed by (13) C-urea breath test (UBT) and PCR. H. pylori 16S rRNA, cagA, hopQ, and vacA genes were amplified from stool DNA samples and sequenced. RESULTS: UBT was positive in 69 (80.2%) of 86 children; in stool DNA analysis, 78.3% were positive by 16S rRNA PCR. cagA, vacA, and hopQ were detected in 66.1%, 84.6%, and 72.3% of stool DNA samples from 16S rRNA-positive children. Of the children's DNA samples, which revealed vacA and hopQ alleles, 91.7% showed vacA s1 and 73.7% showed type I hopQ. Type I hopQ alleles were associated with cagA positivity and vacA s1 genotypes (p < 0.0001). CONCLUSIONS: Using stool DNA samples, virulence markers of H. pylori were successfully genotyped in a high percentage of the asymptomatic infected children, revealing a high prevalence of genotypes associated with virulence. Type I hopQ alleles were associated with the presence of cagA and the vacA s1 genotype.


Assuntos
Antígenos de Bactérias/genética , Proteínas de Bactérias/genética , Infecções por Helicobacter/microbiologia , Helicobacter pylori/genética , Helicobacter pylori/isolamento & purificação , Técnicas de Tipagem Bacteriana , Testes Respiratórios , Criança , Pré-Escolar , Colômbia/epidemiologia , Fezes/microbiologia , Genótipo , Infecções por Helicobacter/diagnóstico , Infecções por Helicobacter/epidemiologia , Helicobacter pylori/classificação , Humanos , Masculino , População Rural
19.
Food Chem Toxicol ; 50(6): 2118-22, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22414649

RESUMO

Gastric cancer (GC) has been associated with a complex combination of genetic and environmental factors. In contrast to most countries, available information on GC mortality trends showed a gradual increase in Mexico. Our aim was to explore potential interactions among dietary (chili pepper consumption), infectious (Helicobacter pylori) and genetic factors (IL1B-31 genotypes) on GC risk. The study was performed in three areas of Mexico, with different GC mortality rates. We included 158 GC patients and 317 clinical controls. Consumption of capsaicin (Cap), the pungent active substance of chili peppers, was estimated by food frequency questionnaire. H. pylori CagA status was assessed by ELISA, and IL1B-31 genotypes were determined by TaqMan assays and Pyrosequencing in DNA samples. Multivariate unconditional logistic regression was used to estimate potential interactions. Moderate to high Cap consumption synergistically increased GC risk in genetically susceptible individuals (IL1B-31C allele carriers) infected with the more virulent H. pylori (CagA+) strains. The combined presence of these factors might explain the absence of a decreasing trend for GC in Mexico. However, further research on gene-environment interactions is required to fully understand the factors determining GC patterns in susceptible populations, with the aim of recommending preventive measures for high risk individuals.


Assuntos
Adenocarcinoma/genética , Adenocarcinoma/microbiologia , Capsaicina/efeitos adversos , Genótipo , Infecções por Helicobacter/microbiologia , Helicobacter pylori/efeitos dos fármacos , Interleucina-1beta/genética , Neoplasias Gástricas/genética , Neoplasias Gástricas/microbiologia , Adulto , Idoso , Anticorpos Antibacterianos/análise , DNA/biossíntese , DNA/genética , Dieta , Feminino , Interação Gene-Ambiente , Infecções por Helicobacter/complicações , Helicobacter pylori/imunologia , Humanos , Imunoglobulina G/análise , Modelos Logísticos , Masculino , México , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase , Risco
20.
J Clin Invest ; 121(5): 1753-67, 2011 May.
Artigo em Inglês | MEDLINE | ID: mdl-21490402

RESUMO

Trefoil factor 1 (TFF1) is a tumor suppressor gene that encodes a peptide belonging to the trefoil factor family of protease-resistant peptides. Although TFF1 expression is frequently lost in gastric carcinomas, the tumorigenic pathways this affects have not been determined. Here we show that Tff1-knockout mice exhibit age-dependent carcinogenic histological changes in the pyloric antrum of the gastric mucosa, progressing from gastritis to hyperplasia, low-grade dysplasia, high-grade dysplasia, and ultimately malignant adenocarcinoma. The histology and molecular signatures of gastric lesions in the Tff1-knockout mice were consistent with an inflammatory phenotype. In vivo, ex-vivo, and in vitro studies showed that TFF1 expression suppressed TNF-α-mediated NF-κB activation through the TNF receptor 1 (TNFR1)/IκB kinase (IKK) pathway. Consistent with these mouse data, human gastric tissue samples displayed a progressive decrease in TFF1 expression and an increase in NF-κB activation along the multi-step carcinogenesis cascade. Collectively, these results provide evidence that loss of TFF1 leads to activation of IKK complex-regulated NF-κB transcription factors and is an important event in shaping the NF-κB-mediated inflammatory response during the progression to gastric tumorigenesis.


Assuntos
NF-kappa B/metabolismo , Peptídeos/metabolismo , Neoplasias Gástricas/metabolismo , Proteínas Supressoras de Tumor/metabolismo , Animais , Progressão da Doença , Mucosa Gástrica/metabolismo , Perfilação da Expressão Gênica , Humanos , Proteínas I-kappa B/metabolismo , Inflamação , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Inibidor de NF-kappaB alfa , Análise de Sequência com Séries de Oligonucleotídeos , Fosforilação , Fator Trefoil-1 , Fator de Necrose Tumoral alfa/metabolismo
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