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Bacterial CagA protein compromises tumor suppressor mechanisms in gastric epithelial cells.
Palrasu M, Zaika E, El-Rifai W, Garcia-Buitrago M, Piazuelo MB, Wilson KT, Peek RM, Zaika AI
(2020) J Clin Invest 130: 2422-2434
MeSH Terms: Antigens, Bacterial, Apoptosis Regulatory Proteins, Bacterial Proteins, Epithelial Cells, Gastric Mucosa, HCT116 Cells, Helicobacter pylori, Humans, Neoplasm Proteins, Proteolysis, Stomach Neoplasms, Ubiquitination, X-Linked Inhibitor of Apoptosis Protein
Show Abstract · Added April 7, 2020
Approximately half of the world's population is infected with the stomach pathogen Helicobacter pylori. Infection with H. pylori is the main risk factor for distal gastric cancer. Bacterial virulence factors, such as the oncoprotein CagA, augment cancer risk. Yet despite high infection rates, only a fraction of H. pylori-infected individuals develop gastric cancer. This raises the question of defining the specific host and bacterial factors responsible for gastric tumorigenesis. To investigate the tumorigenic determinants, we analyzed gastric tissues from human subjects and animals infected with H. pylori bacteria harboring different CagA status. For laboratory studies, well-defined H. pylori strain B128 and its cancerogenic derivative strain 7.13, as well as various bacterial isogenic mutants were employed. We found that H. pylori compromises key tumor suppressor mechanisms: the host stress and apoptotic responses. Our studies showed that CagA induces phosphorylation of XIAP E3 ubiquitin ligase, which enhances ubiquitination and proteasomal degradation of the host proapoptotic factor Siva1. This process is mediated by the PI3K/Akt pathway. Inhibition of Siva1 by H. pylori increases survival of human cells with damaged DNA. It occurs in a strain-specific manner and is associated with the ability to induce gastric tumor.
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13 MeSH Terms
Surveillance of Gastric Intestinal Metaplasia.
Shah SC, Gawron AJ, Li D
(2020) Am J Gastroenterol 115: 641-644
MeSH Terms: Cause of Death, Gastric Mucosa, Global Health, Humans, Morbidity, Patient Selection, Population Surveillance, Precancerous Conditions, Risk Assessment, Stomach Neoplasms, Survival Rate
Added March 3, 2020
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11 MeSH Terms
Spotlight: Gastric Intestinal Metaplasia.
Shah SC, Gupta S, Li D, Morgan D, Mustafa RA, Gawron AJ
(2020) Gastroenterology 158: 704
MeSH Terms: Algorithms, Biopsy, Endoscopy, Gastrointestinal, Gastric Mucosa, Helicobacter Infections, Helicobacter pylori, Humans, Metaplasia, Population Surveillance, Practice Guidelines as Topic, Precancerous Conditions, Risk Factors, Stomach Neoplasms
Added March 3, 2020
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13 MeSH Terms
Histologic Subtyping of Gastric Intestinal Metaplasia: Overview and Considerations for Clinical Practice.
Shah SC, Gawron AJ, Mustafa RA, Piazuelo MB
(2020) Gastroenterology 158: 745-750
MeSH Terms: Biopsy, Endoscopy, Gastrointestinal, Gastric Mucosa, Health Knowledge, Attitudes, Practice, Humans, Metaplasia, Population Surveillance, Precancerous Conditions, Stomach Neoplasms
Added March 3, 2020
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9 MeSH Terms
Advancing the Science in Gastric Pre-Neoplasia: Study Design Considerations.
Davitkov P, Altayar O, Shah SC, Gawron AJ, Mustafa RA, Sultan S, Morgan DR
(2020) Gastroenterology 158: 751-759
MeSH Terms: Biomedical Research, Biopsy, Endoscopy, Gastrointestinal, Gastric Mucosa, Humans, Incidence, Metaplasia, Population Surveillance, Precancerous Conditions, Prevalence, Research Design, Risk Factors, Stomach Neoplasms
Added March 3, 2020
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13 MeSH Terms
AGA Technical Review on Gastric Intestinal Metaplasia-Epidemiology and Risk Factors.
Altayar O, Davitkov P, Shah SC, Gawron AJ, Morgan DR, Turner K, Mustafa RA
(2020) Gastroenterology 158: 732-744.e16
MeSH Terms: Ethnic Groups, European Continental Ancestry Group, Gastric Mucosa, Helicobacter Infections, Helicobacter pylori, Humans, Metaplasia, Precancerous Conditions, Risk Factors, Stomach Neoplasms, United States
Added March 3, 2020
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11 MeSH Terms
AGA Technical Review on Gastric Intestinal Metaplasia-Natural History and Clinical Outcomes.
Gawron AJ, Shah SC, Altayar O, Davitkov P, Morgan D, Turner K, Mustafa RA
(2020) Gastroenterology 158: 705-731.e5
MeSH Terms: Biopsy, Disease Progression, Endoscopy, Gastrointestinal, Gastric Mucosa, Helicobacter Infections, Helicobacter pylori, Humans, Metaplasia, Population Surveillance, Precancerous Conditions, Prevalence, Risk Factors, Stomach Neoplasms, United States
Added March 3, 2020
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14 MeSH Terms
Targeted mobilization of Lrig1 gastric epithelial stem cell populations by a carcinogenic type IV secretion system.
Wroblewski LE, Choi E, Petersen C, Delgado AG, Piazuelo MB, Romero-Gallo J, Lantz TL, Zavros Y, Coffey RJ, Goldenring JR, Zemper AE, Peek RM
(2019) Proc Natl Acad Sci U S A 116: 19652-19658
MeSH Terms: Adenocarcinoma, Animals, Carcinogenesis, Disease Models, Animal, Epithelial Cells, Female, Gastric Mucosa, Gastritis, Helicobacter Infections, Helicobacter pylori, Humans, Male, Membrane Glycoproteins, Mice, Mice, Knockout, Nerve Tissue Proteins, Precancerous Conditions, Primary Cell Culture, Risk Factors, Stem Cells, Stomach, Stomach Neoplasms, Type IV Secretion Systems
Show Abstract · Added September 27, 2019
-induced gastritis is the strongest risk factor for gastric adenocarcinoma, a malignancy preceded by a series of well-defined histological stages, including metaplasia. One microbial constituent that augments cancer risk is the type 4 secretion system (T4SS), which translocates the oncoprotein CagA into host cells. Aberrant stem cell activation is linked to carcinogenesis, and Lrig1 (leucine-rich repeats and Ig-like domains 1) marks a distinct population of progenitor cells. We investigated whether microbial effectors with carcinogenic potential influence Lrig1 progenitor cells ex vivo and via lineage expansion within -infected gastric mucosa. Lineage tracing was induced in (Lrig1/YFP) mice that were uninfected or subsequently infected with or an isogenic mutant (nonfunctional T4SS). In contrast to infection with wild-type (WT) for 2 wk, infection for 8 wk resulted in significantly increased inflammation and proliferation in the corpus and antrum compared with uninfected or mice infected with the mutant. WT -infected mice harbored significantly higher numbers of Lrig1/YFP epithelial cells that coexpressed UEA1 (surface cell marker). The number of cells coexpressing intrinsic factor (chief cell marker), YFP (lineage marker), and GSII lectin (spasmolytic polypeptide-expressing metaplasia marker) were increased only by WT In human samples, Lrig1 expression was significantly increased in lesions with premalignant potential compared with normal mucosa or nonatrophic gastritis. In conclusion, chronic infection stimulates Lrig1-expressing progenitor cells in a -dependent manner, and these reprogrammed cells give rise to a full spectrum of differentiated cells.
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23 MeSH Terms
Resolution of Gastric Cancer-Promoting Inflammation: A Novel Strategy for Anti-cancer Therapy.
Piazuelo MB, Riechelmann RP, Wilson KT, Algood HMS
(2019) Curr Top Microbiol Immunol 421: 319-359
MeSH Terms: Cytokines, Gastric Mucosa, Helicobacter Infections, Helicobacter pylori, Humans, Inflammation, Stomach Neoplasms, Tumor Microenvironment
Show Abstract · Added June 6, 2019
The connection between inflammation and cancer was initially recognized by Rudolf Virchow in the nineteenth century. During the last decades, a large body of evidence has provided support to his hypothesis, and now inflammation is recognized as one of the hallmarks of cancer, both in etiopathogenesis and ongoing tumor growth. Infection with the pathogen Helicobacter pylori is the primary causal factor in 90% of gastric cancer (GC) cases. As we increase our understanding of how chronic inflammation develops in the stomach and contributes to carcinogenesis, there is increasing interest in targeting cancer-promoting inflammation as a strategy to treat GC. Moreover, once cancer develops and anti-cancer immune responses are suppressed, there is evidence of a substantial shift in the microenvironment and new targets for immune therapy emerge. In this chapter, we provide insight into inflammation-related factors, including T lymphocytes, macrophages, pro-inflammatory chemokines, and cytokines, which promote H. pylori-associated GC initiation and growth. While intervening with chronic inflammation is not a new practice in rheumatology or gastroenterology, this approach has not been fully explored for its potential to prevent carcinogenesis or to contribute to the treatment of GC. This review highlights current and possible strategies for therapeutic intervention including (i) targeting pro-inflammatory mediators, (ii) targeting growth factors and pathways involved in angiogenesis in the gastric tumor microenvironment, and (iii) enhancing anti-tumor immunity. In addition, we highlight a significant number of clinical trials and discuss the importance of individual tumor characterization toward offering personalized immune-related therapy.
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8 MeSH Terms
VacA Targets Myeloid Cells in the Gastric Lamina Propria To Promote Peripherally Induced Regulatory T-Cell Differentiation and Persistent Infection.
Altobelli A, Bauer M, Velez K, Cover TL, Müller A
(2019) mBio 10:
MeSH Terms: Animals, Bacterial Proteins, Cell Differentiation, Dendritic Cells, Disease Models, Animal, Gastric Mucosa, Helicobacter Infections, Helicobacter pylori, Immune Evasion, Interleukin-10, Interleukin-23, Lung, Macrophages, Mice, Mucous Membrane, Myeloid Cells, T-Lymphocytes, Regulatory, Transforming Growth Factor beta
Show Abstract · Added April 11, 2019
The gastric bacterium causes a persistent infection that is directly responsible for gastric ulcers and gastric cancer in some patients and protective against allergic and other immunological disorders in others. The two outcomes of the -host interaction can be modeled in mice that are infected as immunocompetent adults and as neonates, respectively. Here, we have investigated the contribution of the immunomodulator VacA to -specific local and systemic immune responses in both models. We found that neonatally infected mice are colonized at higher levels than mice infected as adults and fail to generate effector T-cell responses to the bacteria; rather, T-cell responses in neonatally infected mice are skewed toward Foxp3-positive (Foxp3) regulatory T cells that are neuropilin negative and express RORγt. We found these peripherally induced regulatory T cells (pTregs) to be enriched, in a VacA-dependent manner, not only in the gastric mucosa but also in the lungs of infected mice. Pulmonary pTreg accumulation was observed in mice that have been infected neonatally with wild-type but not in mice that have been infected as adults or mice infected with a VacA null mutant. Finally, we traced VacA to gastric lamina propria myeloid cells and show that it suppressed interleukin-23 (IL-23) expression by dendritic cells and induced IL-10 and TGF-β expression in macrophages. Taken together, the results are consistent with the idea that creates a tolerogenic environment through its immunomodulator VacA, which skews T-cell responses toward Tregs, favors persistence, and affects immunity at distant sites. has coexisted with humans for at least 60.000 years and has evolved persistence strategies that allow it to evade host immunity and colonize its host for life. The VacA protein is expressed by all strains and is required for high-level persistent infection in experimental mouse models. Here, we show that VacA targets myeloid cells in the gastric mucosa to create a tolerogenic environment that facilitates regulatory T-cell differentiation, while suppressing effector T-cell priming and functionality. Tregs that are induced in the periphery during infection can be found not only in the stomach but also in the lungs of infected mice, where they are likely to affect immune responses to allergens.
Copyright © 2019 Altobelli et al.
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18 MeSH Terms