scholarly journals Pathways of Gastric Carcinogenesis, Helicobacter pylori Virulence and Interactions with Antioxidant Systems, Vitamin C and Phytochemicals

2020 ◽  
Vol 21 (17) ◽  
pp. 6451 ◽  
Author(s):  
James W. T. Toh ◽  
Robert B. Wilson

Helicobacter pylori is a class one carcinogen which causes chronic atrophic gastritis, gastric intestinal metaplasia, dysplasia and adenocarcinoma. The mechanisms by which H. pylori interacts with other risk and protective factors, particularly vitamin C in gastric carcinogenesis are complex. Gastric carcinogenesis includes metabolic, environmental, epigenetic, genomic, infective, inflammatory and oncogenic pathways. The molecular classification of gastric cancer subtypes has revolutionized the understanding of gastric carcinogenesis. This includes the tumour microenvironment, germline mutations, and the role of Helicobacter pylori bacteria, Epstein Barr virus and epigenetics in somatic mutations. There is evidence that ascorbic acid, phytochemicals and endogenous antioxidant systems can modify the risk of gastric cancer. Gastric juice ascorbate levels depend on dietary intake of ascorbic acid but can also be decreased by H. pylori infection, H. pylori CagA secretion, tobacco smoking, achlorhydria and chronic atrophic gastritis. Ascorbic acid may be protective against gastric cancer by its antioxidant effect in gastric cytoprotection, regenerating active vitamin E and glutathione, inhibiting endogenous N-nitrosation, reducing toxic effects of ingested nitrosodimethylamines and heterocyclic amines, and preventing H. pylori infection. The effectiveness of such cytoprotection is related to H. pylori strain virulence, particularly CagA expression. The role of vitamin C in epigenetic reprogramming in gastric cancer is still evolving. Other factors in conjunction with vitamin C also play a role in gastric carcinogenesis. Eradication of H. pylori may lead to recovery of vitamin C secretion by gastric epithelium and enable regression of premalignant gastric lesions, thereby interrupting the Correa cascade of gastric carcinogenesis.

2021 ◽  
Vol 12 ◽  
Author(s):  
Mariagrazia Piscione ◽  
Mariangela Mazzone ◽  
Maria Carmela Di Marcantonio ◽  
Raffaella Muraro ◽  
Gabriella Mincione

Worldwide, gastric cancer (GC) represents the fifth cancer for incidence, and the third as cause of death in developed countries. Indeed, it resulted in more than 780,000 deaths in 2018. Helicobacter pylori appears to be responsible for the majority of these cancers. On the basis of recent studies, and either alone or combined with additional etiological factors, H. pylori is considered a “type I carcinogen.” Over recent decades, new insights have been obtained into the strategies that have been adopted by H. pylori to survive the acidic conditions of the gastric environment, and to result in persistent infection, and dysregulation of host functions. The multistep processes involved in the development of GC are initiated by transition of the mucosa into chronic non-atrophic gastritis, which is primarily triggered by infection with H. pylori. This gastritis then progresses into atrophic gastritis and intestinal metaplasia, and then to dysplasia, and following Correa’s cascade, to adenocarcinoma. The use of antibiotics for eradication of H. pylori can reduce the incidence of precancerous lesions only in the early stages of gastric carcinogenesis. Here, we first survey the etiology and risk factors of GC, and then we analyze the mechanisms underlying tumorigenesis induced by H. pylori, focusing attention on virulence factor CagA, inflammation, oxidative stress, and ErbB2 receptor tyrosine kinase. Moreover, we investigate the relationships between H. pylori eradication therapy and other diseases, considering not only cardia (upper stomach) cancers and Barrett’s esophagus, but also asthma and allergies, through discussion of the “hygiene hypothesis. ” This hypothesis suggests that improved hygiene and antibiotic use in early life reduces microbial exposure, such that the immune response does not become primed, and individuals are not protected against atopic disorders, asthma, and autoimmune diseases. Finally, we overview recent advances to uncover the complex interplay between H. pylori and the gut microbiota during gastric carcinogenesis, as characterized by reduced bacterial diversity and increased microbial dysbiosis. Indeed, it is of particular importance to identify the bacterial taxa of the stomach that might predict the outcome of gastric disease through the stages of Correa’s cascade, to improve prevention and therapy of gastric carcinoma.


2016 ◽  
Vol 54 (3) ◽  
pp. 151-156 ◽  
Author(s):  
Alexandra Loor ◽  
D.L. Dumitraşcu

Abstract Gastric cancer (GC) is one of the most widespread types of cancer worldwide. Helicobacter pylori infection has been clearly correlated with gastric carcinogenesis. At present and in the near future, the most important challenge is and will be the significant reduction of mortality due to GC. That goal can be achieved through the identification of higher-risk patients, such as those with atrophic gastritis, intestinal metaplasia and dysplasia. In this review we intend to discuss the importance of diagnosing H. pylori infection and chronic atrophic gastritis in preventing gastric cancer, using a new non-invasive test called GastroPanel. This test is a classification algorithm including four biochemical parameters pepsinogen I and II (PGI and PGII), gastrin-17 (G17), and anti-Helicobacter pylori antibodies (Ig G anti-Hp) measured in fasting sera, which allows to classify patients as having atrophic or non-atrophic gastritis and to find whether gastritis is associated or not with H. pylori infection. GastroPanel is not a “cancer test”, but it can and should be used in the screening and diagnosis of subjects with a high cancer risk; still, a careful diagnostic made by superior digestive endoscopy is compulsory to find possible precancerous or cancerous lesions at an early and curable stage.


2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Soichiro Sue ◽  
Wataru Shibata ◽  
Shin Maeda

Helicobacter pylori(H. pylori) induces chronic gastric inflammation, atrophic gastritis, intestinal metaplasia, and cancer. Although the risk of gastric cancer increases exponentially with the extent of atrophic gastritis, the precise mechanisms of gastric carcinogenesis have not been fully elucidated.H. pyloriinduces genetic and epigenetic changes in gastric epithelial cells through activating intracellular signaling pathways in a cagPAI-dependent manner.H. pylorieventually induces gastric cancer with chromosomal instability (CIN) or microsatellite instability (MSI), which are classified as two major subtypes of gastric cancer. Elucidation of the precise mechanisms of gastric carcinogenesis will also be important for cancer therapy.


2018 ◽  
Vol 01 (1) ◽  
Author(s):  
Takalkar U Vidyadhar

Gastric cancer is a multifactorial disease with complex interplay of environmental and genetic factors. Helicobacter pylori (H. pylori) infestation has been identified as the most important etiological agent in the pathogenesis of gastric cancer. Also, the role of dietary factors that is low consumption of fruits and vegetables have been found to be associated with gastric cancer. Among the dietary factors, antioxidants especially vitamin C has been found to confer the strongest protection against gastric cancer. Its anti-proliferative and pro-apoptotic action has been suggested in vitro. Because of its antioxidant activity, it protects cells against oxidative DNA damage caused by toxic effects of reactive oxygen species. It also inhibits production of carcinogenic N-nitroso compound in the stomach. The person with H. pylori infection has low levels of vitamin C in their gastric juice and levels of vitamin C normalizes on eradication of H. pylori. Vitamin C levels are high in gastric mucosa and gastric juice, sometimes more than that of in plasma. But gastric pathological conditions cause lowered secretion of vitamin C into gastric juice. Effect of H. pylori on vitamin C in gastric juice is reversible and on eradication of H. pylori, it returns to normal level. Hence, eradication of H. pylori and chemoprevention with antioxidant supplementation will be an effective preventive strategy to reduce the incidence of gastric cancer and related mortality. Vitamin C and gastric cancer is an area of potential interest for researchers as a preventive measure. Keywords: Vitamin C, H. pylori, gastric cancer.


mBio ◽  
2014 ◽  
Vol 5 (4) ◽  
Author(s):  
Adria Carbo ◽  
Danyvid Olivares-Villagómez ◽  
Raquel Hontecillas ◽  
Josep Bassaganya-Riera ◽  
Rupesh Chaturvedi ◽  
...  

ABSTRACTThe development of gastritis duringHelicobacter pyloriinfection is dependent on an activated adaptive immune response orchestrated by T helper (Th) cells. However, the relative contributions of the Th1 and Th17 subsets to gastritis and control of infection are still under investigation. To investigate the role of interleukin-21 (IL-21) in the gastric mucosa duringH. pyloriinfection, we combined mathematical modeling of CD4+T cell differentiation within vivomechanistic studies. We infected IL-21-deficient and wild-type mice withH. pyloristrain SS1 and assessed colonization, gastric inflammation, cellular infiltration, and cytokine profiles. ChronicallyH. pylori-infected IL-21-deficient mice had higherH. pyloricolonization, significantly less gastritis, and reduced expression of proinflammatory cytokines and chemokines compared to these parameters in infected wild-type littermates. Thesein vivodata were used to calibrate anH. pyloriinfection-dependent, CD4+T cell-specific computational model, which then described the mechanism by which IL-21 activates the production of interferon gamma (IFN-γ) and IL-17 during chronicH. pyloriinfection. The model predicted activated expression of T-bet and RORγt and the phosphorylation of STAT3 and STAT1 and suggested a potential role of IL-21 in the modulation of IL-10. Driven by our modeling-derived predictions, we found reduced levels of CD4+splenocyte-specifictbx21androrcexpression, reduced phosphorylation of STAT1 and STAT3, and an increase in CD4+T cell-specific IL-10 expression inH. pylori-infected IL-21-deficient mice. Our results indicate that IL-21 regulates Th1 and Th17 effector responses during chronicH. pyloriinfection in a STAT1- and STAT3-dependent manner, therefore playing a major role controllingH. pyloriinfection and gastritis.IMPORTANCEHelicobacter pyloriis the dominant member of the gastric microbiota in more than 50% of the world’s population.H. pyloricolonization has been implicated in gastritis and gastric cancer, as infection withH. pyloriis the single most common risk factor for gastric cancer. Current data suggest that, in addition to bacterial virulence factors, the magnitude and types of immune responses influence the outcome of colonization and chronic infection. This study uses a combined computational and experimental approach to investigate how IL-21, a proinflammatory T cell-derived cytokine, maintains the chronic proinflammatory T cell immune response driving chronic gastritis duringH. pyloriinfection. This research will also provide insight into a myriad of other infectious and immune disorders in which IL-21 is increasingly recognized to play a central role. The use of IL-21-related therapies may provide treatment options for individuals chronically colonized withH. pylorias an alternative to aggressive antibiotics.


2020 ◽  
Author(s):  
Faisal Aziz ◽  
Mingxia Xin ◽  
Yunfeng Gao ◽  
Josh Monts ◽  
Kjersten Monson ◽  
...  

Abstract Background: Gastric cancer risk evolves over time due to environmental, dietary, and lifestyle changes including Helicobacter pylori (H. pylori) infection and consumption of hot peppers (i.e. capsaicin). H. pylori infection promotes gastric mucosal injury in the early phase of capsaicin exposure. In addition, capsaicin consumption is reported to suppress immune function and increase host susceptibility to microbial infection. This relationship suggests a need to investigate the mechanism of how both H. pylori infection and capsaicin contribute to gastric inflammation and lead to gastric cancer. No previous experimental animal models have been developed to study this dual association. Here we developed a series of mouse models that progress from chronic gastritis to gastric cancer. C57-Balb/c mice were infected with the H. pylori (SS1) strain and then fed capsaicin (0.05% or 0.2g/kg/day) or not. Consequently, we investigated the association between H. pylori infection and capsaicin consumption during the initiation of gastric inflammation and the later development of gastric cancer. Tumor size and phenotype were analyzed to determine the molecular mechanism driving the shift from gastritis to stomach cancer. Gastric carcinogenesis was also prevented in these models using the ornithine decarboxylase inhibitor DFMO (2-difluoromethylornithine). Results: This study provides evidence showing that a combination of H. pylori infection and capsaicin consumption leads to gastric carcinogenesis. The transition from chronic gastritis to gastric cancer is mediated through interleukin-6 (IL-6) stimulation with an incidence rate of 50%. However, this progression can be prevented by treating with anti-inflammatory agents. In particular, we used DFMO to prevent gastric tumorigenesis by reducing inflammation and promoting recovery of disease-free stasis. The anti-inflammatory role of DFMO highlights the injurious effect of inflammation in gastric cancer development and the need to reduce gastric inflammation for cancer prevention. Conclusions: Overall, these mouse models provide reliable systems for analyzing the molecular mechanisms and synergistic effects of H. pylori and capsaicin on human cancer etiology. Accordingly, preventive measures like reduced capsaicin consumption, H. pylori clearance, and DFMO treatment can lessen gastric cancer incidence. Lastly, anti-inflammatory agents like DFMO can play important roles in prevention of inflammation-associated gastric cancer.


2020 ◽  
Author(s):  
Shihua Wu ◽  
Chunmei Bao ◽  
Ruilin Wang ◽  
Xiaomei Zhang ◽  
Sijia Gao ◽  
...  

Abstract Background: Zuojin Pill (ZJP), a famous Chinese medicinal formula, widely accepted for treatment of chronic atrophic gastritis (CAG) in China. This study aimed to explore the therapeutic effects and mechanisms of ZJP in Helicobacter pylori (H. pylori) - induced chronic atrophic gastritis (CAG) in vivo and in vitro. Methods: CAG rat model was induced by H. pylori. ZJP (0.63, 1.26, and 2.52 g/kg, respectively) was administered orally for four weeks. Therapeutic effects of ZJP were identified by H&E staining and serum indices. In addition, cell viability, morphology and proliferation were detected by cell counting kit-8 (CCK8) and high-content screening assay (HCS), respectively. Moreover, relative mRNA expression and protein expression related to JMJD2B/COX-2/VEGF axis was detected to investigate the potential mechanisms of ZJP in CAG. Results: Results showed the symptoms (weight loss and gastric mucosa damage) of CAG were alleviated, and the contents of TNF-α in serum was markedly decreased after treating with ZJP. Moreover, cell viability, proliferation and morphology changes of GES-1 cells were ameliorated by ZJP intervention. In addition, proinflammatory genes and JMJD2B/COX-2/VEGF axis related genes were suppressed by ZJP administration in vitro and in vivo. Meanwhile, immunohistochemistry (IHC) and western blot confirmed down-regulation of these genes by ZJP intervention. Conclusion: ZJP treatment can alleviate gastric mucosal damage induced by H. pylori via JMJD2B/COX-2/VEGF axis.


2016 ◽  
Vol 8 (3) ◽  
Author(s):  
Concetta De Luca ◽  
Annalisa Mancin ◽  
Maria Calabrò ◽  
Cristina Daleno ◽  
Antonella Ferrario ◽  
...  

We report a case of <em>Helicobacter pylori</em> transient bacteremia in a woman with ulcerated antral gastric cancer. The patient was hospitalized for laparoscopy and subtotal gastrectomy. After surgery she developed fever (39°C) and was empirically treated with levofloxacin. Blood cultures, collected and sent immediately to Laboratory, were positive for a spiral Gramnegative bacterium. This isolate was identified as <em>H. pylori</em> and the specific susceptibility test was performed. One day after the fever was decreased but antibiotic treatment with levofloxacin was continued and it was maintained until discharge. In summary, <em>H. pylori</em> transient bacteremia may occur as a rare complication after stomach surgery. Further studies are necessary to elucidate the potential role of <em>H</em>. <em>pylori</em> presence in blood.


2019 ◽  
Vol 12 ◽  
pp. 175628481989406 ◽  
Author(s):  
Christian Schulz ◽  
Kerstin Schütte ◽  
Julia Mayerle ◽  
Peter Malfertheiner

A link between chronic inflammation and carcinogenesis has been depicted in many organ systems. Helicobacter pylori is the most prevalent bacterial pathogen, induces chronic gastritis and is associated with more than 90% of cases of gastric cancer (GC). However, the introduction of nucleotide sequencing techniques and the development of biocomputional tools have surpassed traditional culturing techniques and opened a wide field for studying the mucosal and luminal composition of the bacterial gastric microbiota beyond H. pylori. In studies applying animal models, a potential role in gastric carcinogenesis for additional bacteria besides H. pylori has been demonstrated. At different steps of gastric carcinogenesis, changes in bacterial communities occur. Whether these microbial changes are a driver of malignant disease or a consequence of the histologic progression along the precancerous cascade, is not clear at present. It is hypothesized that atrophy, as a consequence of chronic gastric inflammation, alters the gastric niche for commensals that might further urge the development of H. pylori-induced GC. Here, we review the current state of knowledge on gastric bacteria other than H. pylori and on their synergism with H. pylori in gastric carcinogenesis.


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