Helicobacter pylori infection and gastric carcinoma

Antibiotic resistance in Helicobacter pylori among children and adolescents in East Asia: A systematic review and meta-analysis

BACKGROUND

In East Asia, Helicobacter pylori ( H. pylori ) infection and related diseases are common, primarily during childhood and adolescence. The rates of primary antibiotic resistance in H. pylori among East Asian children and adolescents have not been extensively explored; few relevant systematic reviews or meta-analyses have been conducted. We evaluated the rates of antibiotic resistance in H. pylori among East Asian children and adolescents, with the goal of facilitating individualized treatment recommendations.

METHODS

We searched PubMed, Embase, and the Cochrane Library for studies in any language published up to February 2023 that explored antibiotic resistance in H. pylori among East Asian children and adolescents. We used MeSH and non-MeSH terms related to the topic, including terms related to children, adolescents, antibiotic resistance, H. pylori , and nations or regions. Additionally, we reviewed the reference lists of relevant articles. Studies that matched our strict predefined eligibility criteria were included in the screening process. Using established assessment methods, we evaluated the quality of the included studies.

RESULTS

We identified 15 observational studies involving 4831 H. pylori isolates, all published between 2001 and 2022. There was substantial primary antibiotic resistance in H. pylori isolates from East Asian children and adolescents. The rates of primary resistance were 51% (95% confidence interval [CI]: 40-62%) for metronidazole; 37% (95% CI: 20-53%) for clarithromycin; 19% (95% CI: 11-28%) for levofloxacin; and less than 3% each for amoxicillin, tetracycline, and furazolidone. Subgroup analysis revealed a prominent increase in metronidazole resistance over time. Clarithromycin and levofloxacin resistance rates fluctuated between 2005 and 2015, then remained stable; other antibiotic resistance rates were generally stable. Metronidazole, clarithromycin, and levofloxacin resistance rates were significantly higher in the Chinese mainland than in other East Asian regions. The rates of dual and multiple antibiotic resistance were 28% (95% CI: 21-36%) and 10% (95% CI: 7-14%), highlighting the potential for diverse resistance patterns.

CONCLUSIONS

H. pylori isolates from East Asian children and adolescents exhibit high levels of metronidazole and clarithromycin resistance, particularly in the Chinese mainland. The non-negligible rates of dual and multiple resistance highlight the complexity of this problem.

REGISTRATION

PROSPERO, No. CRD42023402510.

Effect of Lactobacillus gasseri BIO6369 and Lacticaseibacillus rhamnosus BIO5326 on Gastric Carcinogenesis Induced by Helicobacter pylori Infection

BACKGROUND

Helicobacter pylori infection-associated gastric adenocarcinoma is influenced by various factors, including the digestive microbiota. Lactic acid bacteria role in digestive carcinogenesis has been discussed, and some Lactobacillaceae family species have been shown to act against H. pylori-induced inflammation and colonization. However, their effects on H. pylori-related carcinogenesis have not yet been studied. Lactobacillaceae family effects on the epithelial-to-mesenchymal transition (EMT), emergence of cells with cancer stem cell (CSC) properties and the pro-inflammatory response of gastric epithelial cells to H. pylori infection were investigated.

MATERIALS AND METHODS

A co-culture model of AGS gastric epithelial cells infected with a carcinogenic strain of H. pylori associated with 18 different probiotic strains candidates were used. Different EMT indicators and CSC properties were studied, including quantification of the mesenchymal phenotype, tumorsphere formation, EMT marker expression, and tight junction evaluation with immunofluorescence microscopy. The effect of the strains on the pro-inflammatory response to H. pylori was also evaluated by quantifying interleukin-8 (IL-8) production using ELISA.

RESULTS

Among the strains tested, Lactobacillus gasseri BIO6369 and Lacticaseibacillus rhamnosus BIO5326 induced a 30.6% and 38.4% reduction in the mesenchymal phenotype, respectively, caused a significant decrease in Snail and Zeb1 EMT marker expression and prevented the loss of tight junctions induced by H. pylori infection. A separate co-culture with a Boyden chamber maintained the effects induced by the two strains. H. pylori-induced IL-8 production was also significantly reduced in the presence of L. gasseri BIO6369 and L. rhamnosus BIO5326.

CONCLUSION

Lactobacillus gasseri BIO6369 and L. rhamnosus BIO5326 strains decreased epithelial-to-mesenchymal transition and inflammation induced by H. pylori infection, suggesting that these species may have a protective effect against H. pylori-induced gastric carcinogenesis.

Helicobacter pylori: A Contemporary Perspective on Pathogenesis, Diagnosis and Treatment Strategies

Helicobacter pylori (H. pylori) is a Gram-negative bacterium that colonizes the gastric mucosa and is associated with various gastrointestinal disorders. H. pylori is a pervasive pathogen, infecting nearly 50% of the world's population, and presents a substantial concern due to its link with gastric cancer, ranking as the third most common cause of global cancer-related mortality. This review article provides an updated and comprehensive overview of the current understanding of H. pylori infection, focusing on its pathogenesis, diagnosis, and treatment strategies. The intricate mechanisms underlying its pathogenesis, including the virulence factors and host interactions, are discussed in detail. The diagnostic methods, ranging from the traditional techniques to the advanced molecular approaches, are explored, highlighting their strengths and limitations. The evolving landscape of treatment strategies, including antibiotic regimens and emerging therapeutic approaches, is thoroughly examined. Through a critical synthesis of the recent research findings, this article offers valuable insights into the contemporary knowledge of Helicobacter pylori infection, guiding both clinicians and researchers toward effective management and future directions in combating this global health challenge.

Single-nucleotide polymorphism in CYP1A1, CYP1B1, CYP2B6, CYP2C8, and CYP2C9 genes and their association with gastrointestinal cancer: A hospital-based case-control study

BACKGROUND

Cytochrome P450 (CYP) comprises a group of phase-I metabolizing enzymes that are important in xenobiotics metabolism. Genetic polymorphism of CYPs has been comprehensively studied for their association with a range of diseases. In this study, we assessed single-nucleotide polymorphism (SNP) of CYP1A, CYP1B, CYP2B, and CYP2C and their role in gastrointestinal (GI) cancer susceptibility in the rural population of Maharashtra.

MATERIALS AND METHODS

In this hospital-based case-control study, the association of polymorphism of CYP genes was studied by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. The study subjects included 200 clinically confirmed GI cancer patients and equal number of healthy controls. Odds ratio (OR) with 95% confidence interval (CI) and P value were evaluated to find out the level of association, where P ≤ 0.005 was considered statistically significant.

RESULTS

After the analysis of CYP1A1*2A (rs4646903), CYP1B1*3 (rs1059836), CYP2B6*5 (rs3211371), CYP2C8*2 (rs11572103), CYP2C9*2 (rs1799853), and CYP2C9*3 (rs1057910), we noticed that variant (T) allele of CYP2B6*5 possessed significantly elevated risk (OR = 4.43; 95% CI: 2.20-8.90; P < 0.0001) of GI cancer in studied population. The genotypic distribution of G/C heterozygote allele of CYP1B1*3 (OR = 0.19, 95% CI = 0.12-0.32; P < 0.0001) and homozygous variant C/C allele (OR = 0.24, 95% CI = 0.13-0.45; P < 0.0001) showed a negative association with the development of GI cancer.

CONCLUSION

The findings from this study supported that polymorphism of CYP2B6*5gene may be involved in the development of GI cancer. However, other SNPs of CYP1A, CYP1B, and CYP2C genes did not signify the risk for GI cancer in the studied population of rural Maharashtra.

The role of gastric microecological dysbiosis in gastric carcinogenesis

Gastric cancer (GC) is the leading cause of cancer-related death worldwide, and reducing its mortality has become an urgent public health issue. Gastric microecological dysbiosis (including bacteria, fungi, viruses, acid suppressants, antibiotics, and surgery) can lead to gastric immune dysfunction or result in a decrease in dominant bacteria and an increase in the number and virulence of pathogenic microorganisms, which in turn promotes development of GC. This review analyzes the relationship between gastric microecological dysbiosis and GC, elucidates dynamic alterations of the microbiota in Correa's cascade, and identifies certain specific microorganisms as potential biomarkers of GC to aid in early screening and diagnosis. In addition, this paper presents the potential of gastric microbiota transplantation as a therapeutic target for gastric cancer, providing a new direction for future research in this field.

Differential Proteomics of Helicobacter pylori Isolates from Gastritis, Ulcer, and Cancer Patients: First Study from Northwest Pakistan

Background and Objective: Helicobacter pylori is a human-stomach-dwelling organism that causes many gastric illnesses, including gastritis, ulcer, and gastric cancer. The purpose of the study was to perform differential proteomic analysis on H. pylori isolates from gastritis, ulcer, and gastric cancer patients. Materials and Methods: H. pylori was isolated from antrum and fundus biopsies obtained from patients who visited the Department of Gastroenterology. Using nano-LC-QTOF MS/MS analysis, differentially regulated proteins were identified through proteome profiling of pooled samples of H. pylori isolated from gastritis, ulcer, and gastric cancer patients. Antigenic scores and cellular localization of proteins were determined using additional prediction tools. Results: A total of 14 significantly regulated proteins were identified in H. pylori isolated from patients with either gastritis, ulcer, or gastric cancer. Comparative analysis of groups revealed that in the case of cancer vs. gastritis, six proteins were overexpressed, out of which two proteins, including hydrogenase maturation factor (hypA) and nucleoside diphosphate kinase (ndk) involved in bacterial colonization, were only upregulated in isolates from cancer patients. Similarly, in cancer vs. ulcer, a total of nine proteins were expressed. Sec-independent protein translocase protein (tatB), involved in protein translocation, and pseudaminic acid synthase I (pseI), involved in the synthesis of functional flagella, were upregulated in cancer, while hypA and ndk were downregulated. In ulcer vs. gastritis, eight proteins were expressed. In this group, tatB was overexpressed. A reduction in thioredoxin peroxidase (bacterioferritin co-migratory protein (bcp)) was observed in ulcer vs. gastritis and cancer vs. ulcer. Conclusion: Our study suggested three discrete protein signatures, hypA, tatB, and bcp, with differential expression in gastritis, ulcer, and cancer. Protein expression profiles of H. pylori isolated from patients with these gastric diseases will help to understand the virulence and pathogenesis of H. pylori.

Helicobacter pylori-Induced Progranulin Promotes the Progression of the Gastric Epithelial Cell Cycle by Regulating CDK4

Helicobacter pylori, a group 1 carcinogen, colonizes the stomach and affects the development of stomach diseases. Progranulin (PGRN) is an autocrine growth factor that regulates multiple cellular processes and plays a tumorigenic role in many tissues. Nevertheless, the mechanism of action of PGRN in gastric cancer caused by H. pylori infection remains unclear. Here, we investigated the role of PGRN in cell cycle progression and the cell proliferation induced by H. pylori infection. We found that the increased PGRN was positively associated with CDK4 expression in gastric cancer tissue. PGRN was upregulated by H. pylori infection, thereby promoting cell proliferation, and that enhanced level of proliferation was reduced by PGRN inhibitor. CDK4, a target gene of PGRN, is a cyclin-dependent kinase that binds to cyclin D to promote cell cycle progression, which was upregulated by H. pylori infection. We also showed that knockdown of CDK4 reduced the higher cell cycle progression caused by upregulated PGRN. Moreover, when the PI3K/Akt signaling pathway (which is promoted by PGRN) was blocked, the upregulation of CDK4 mediated by PGRN was reduced. These results reveal the potential mechanism by which PGRN plays a major role through CDK4 in the pathological mechanism of H. pylori infection.

Caulerpin Mitigates Helicobacter pylori-Induced Inflammation via Formyl Peptide Receptors

The identification of novel strategies to control Helicobacter pylori (Hp)-associated chronic inflammation is, at present, a considerable challenge. Here, we attempt to combat this issue by modulating the innate immune response, targeting formyl peptide receptors (FPRs), G-protein coupled receptors that play key roles in both the regulation and the resolution of the innate inflammatory response. Specifically, we investigated, in vitro, whether Caulerpin—a bis-indole alkaloid isolated from algae of the genus Caulerpa—could act as a molecular antagonist scaffold of FPRs. We showed that Caulerpin significantly reduces the immune response against Hp culture filtrate, by reverting the FPR2-related signaling cascade and thus counteracting the inflammatory reaction triggered by Hp peptide Hp(2–20). Our study suggests Caulerpin to be a promising therapeutic or adjuvant agent for the attenuation of inflammation triggered by Hp infection, as well as its related adverse clinical outcomes.

The uninvited guests of our microbiome: Helicobacter pylori and Epstein-Barr virus and their role in gastric cancerogenesis

It is well established that human body is an ecosystem for numerous microorganisms: bacteria, fungi, eukaryotic parasites, and viruses. They form a “microbiome” that under conditions of homeostasis remains in a friendly mutual relationship with the host. However, the composition and diversity of this microbe community is dynamic and can be changed under the influence of environmental factors, such as diet, antibiotic therapy, lifestyle, and the host’s genotype and immunity. The result of gut microbiome dysbiosis can lead even to cancer. The aim of this review is the description of the healthy gastrointestinal microbiome and the role of two infectious agents: Gram-negative bacteria Helicobacter pylori and Epstein-Barr virus in the development of gastric cancer in terms of gut dysbiosis. H. pylori is the most important pathogen of gastric microbiome with clear impact on its diversity. Coinfection with Epstein-Barr virus causes chronic gastritis, and the inflammatory process is significantly increased. The process of carcinogenesis begins with chronic inflammation that causes atrophic gastritis, intestinal metaplasia, dysplasia, and finally cancer. It has been proven that chronic inflammatory infection caused by infectious agents increases the risk of stomach cancer. Molecular methods that are progressively used to explore the human microbiome provide hope that this knowledge will be used for future diagnoses and therapy in the state of its dysbiosis and in cases of gastric cancer.

Gastric Microbiota beyond H. pylori: An Emerging Critical Character in Gastric Carcinogenesis

Gastric cancer (GC) is one of the global leading causes of cancer death. The association between Helicobacter pylori, which is a predominant risk factor for GC, with GC development has been well-studied. Recently, accumulating evidence has demonstrated the presence of a large population of microorganisms other than H. pylori in the human stomach. Existing sequencing studies have revealed microbial compositional and functional alterations in patients with GC and highlighted a progressive shift in the gastric microbiota in gastric carcinogenesis with marked enrichments of oral or intestinal commensals. Moreover, using a combination of gastric bacterial signatures, GC patients could be significantly distinguished from patients with gastritis. These findings, therefore, emphasize the importance of a collective microbial community in gastric carcinogenesis. Here, we provide an overview of non-H. pylori gastric microbes in gastric carcinogenesis. The molecular mechanisms of gastric microbes-related carcinogenesis and potential clinical applications of gastric microbiota as biomarkers of GC are also explored.

Under the Radar: Strategies Used by Helicobacter pylori to Evade Host Responses

The body depends on its physical barriers and innate and adaptive immune responses to defend against the constant assault of potentially harmful microbes. In turn, successful pathogens have evolved unique mechanisms to adapt to the host environment and manipulate host defenses. Helicobacter pylori (Hp), a human gastric pathogen that is acquired in childhood and persists throughout life, is an example of a bacterium that is very successful at remodeling the host-pathogen interface to promote a long-term persistent infection. Using a combination of secreted virulence factors, immune subversion, and manipulation of cellular mechanisms, Hp can colonize and persist in the hostile environment of the human stomach. Here, we review the most recent and relevant information regarding how this successful pathogen overcomes gastric epithelial host defense responses to facilitate its own survival and establish a chronic infection. Expected final online publication date for the Annual Review of Physiology, Volume 84 is February 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Helicobacters and cancer, not only gastric cancer?

The Helicobacter genus actually comprises 46 validly published species divided into two main clades: gastric and enterohepatic Helicobacters. These bacteria colonize alternative sites of the digestive system in animals and humans, and contribute to inflammation and cancers. In humans, Helicobacter infection is mainly related to H. pylori, a gastric pathogen infecting more than half of the world's population, leading to chronic inflammation of the gastric mucosa that can evolve into two types of gastric cancers: gastric adenocarcinomas and gastric MALT lymphoma. In addition, H. pylori but also non-H. pylori Helicobacter infection has been associated with many extra-gastric malignancies. This review focuses on H. pylori and its role in gastric cancers and extra-gastric diseases, as well as malignancies induced by non-H. pylori Helicobacters. Their different virulence factors and their involvement in carcinogenesis is discussed. This review highlights the importance of both gastric and enterohepatic Helicobacters in gastrointestinal and liver cancers.

Statins' Regulation of the Virulence Factors of Helicobacter pylori and the Production of ROS May Inhibit the Development of Gastric Cancer

Conventionally, statins are used to treat high cholesterol levels. They exhibit pleiotropic effects, such as the prevention of cardiovascular disease and decreased cancer mortality. Gastric cancer (GC) is one of the most common cancers, ranking as the third leading global cause of cancer-related deaths, and is mainly attributed to chronic Helicobacter pylori infection. During their co-evolution with hosts, H. pylori has developed the ability to use the cellular components of the host to evade the immune system and multiply in intracellular niches. Certain H. pylori virulence factors, including cytotoxin-associated gene A (CagA), vacuolating cytotoxin A (VacA), and cholesterol-α-glucosyltransferase (CGT), have been shown to exploit host cholesterol during pathogenesis. Therefore, using statins to antagonize cholesterol synthesis might prove to be an ideal strategy for reducing the occurrence of H. pylori-related GC. This review discusses the current understanding of the interplay of H. pylori virulence factors with cholesterol and reactive oxygen species (ROS) production, which may prove to be novel therapeutic targets for the development of effective treatment strategies against H. pylori-associated GC. We also summarize the findings of several clinical studies on the association between statin therapy and the development of GC, especially in terms of cancer risk and mortality.

Identification of antibiotic resistance patterns in Helicobacter pylori strains isolated from gastric biopsies using real-time PCR and genotypic analysis

BACKGROUND

Helicobacter pylori (H. pylori) is associated with dyspepsia, mucus-associated lymphoid tissue lymphoma, gastritis, and peptic ulcer disease. Treatment in Malta consists of triple therapy, which consists of a proton pump inhibitor and 2 of the antibiotics amoxicillin, clarithromycin, metronidazole and fluoroquinolones. We aimed to determine the resistance rates for clarithromycin and fluoroquinolones in patients with H. pylori, and its incidence, in patients undergoing an esophagogastroduodenoscopy (EGD) using real-time polymerase chain reaction (RT-PCR).

METHODS

Patients undergoing an EGD were recruited. A rapid urease test (RUT) was performed, and 4 gastric biopsies were also taken (2 from antrum, 2 from corpus) and analyzed using RT-PCR. Positive samples were tested for antibiotic resistance using amplification and reverse hybridization techniques.

RESULTS

Two hundred patients (mean age 53.6 [range 20-92] years; 53.1% female) were recruited; the majority were (78%) non-smokers. H. pylori was identified in 21.0% of the patients. Fluoroquinolone resistance was detected in 21.4% of the patients. Clarithromycin resistance was observed in 26.2%, with dual resistance identified in 4.8% of the patients. A high concordance was present with patients testing negative for H. pylori with both RUT and RT-PCR (94.3%). Only 57.6% of patients tested positive with both tests. However, 92.9% of RT-PCR positive patients had a positive genotype HelicoDR test.

CONCLUSIONS

This data demonstrates a high rate of H. pylori resistance to both clarithromycin and fluoroquinolones. These should be avoided when treating H. pylori by utilizing different treatment regimes. Furthermore, we derived important data on the role of RT-PCR, which may be implemented in routine clinical practice.

Metformin Modifies the Gut Microbiota of Mice Infected with Helicobacter pylori

Metformin is widely prescribed to treat type 2 diabetes. Diabetes patients treated with metformin have a decreased risk of cancers, including gastric cancer. Among the factors influencing digestive carcinogenesis, gut microbiota interactions have been intensively studied. Metformin exhibits direct antimicrobial activity toward Helicobacterpylori, which plays a crucial role in gastric carcinogenesis. Mice were infected with H. pylori and treated for 12 days with either metformin or phosphate-buffered saline (PBS) as a control. At the end of the treatment period, the mice were euthanized and cecal and intestinal contents and stool were collected. The gut microbiota of the three different digestive sites (stool, cecal, and intestinal contents) were characterized through 16S RNA gene sequencing. In mice infected with H. pylori, metformin significantly decreased alpha diversity indices and led to significant variation in the relative abundance of some bacterial taxa including Clostridium and Lactobacillus, which were directly inhibited by metformin in vitro. PICRUSt analysis suggested that metformin modifies functional pathway expression, including a decrease in nitrate reducing bacteria in the intestine. Metformin significantly changed the composition and predicted function of the gut microbiota of mice infected with H. pylori; these modifications could be implicated in digestive cancer prevention.

Dual Role of Bacteria in Carcinoma: Stimulation and Inhibition

Although what unifies the carcinogenic microorganisms has not been determined by multiple studies, the role of bacteria in the development of neoplasms has not been properly elucidated. In this review, we discuss links between the bacterial species and cancer, with focus on immune responses for the stimulation of tumor cells such as induction of inflammation. Finally, we will describe the potential therapeutic strategies of bacteria on target tumors to improve treatment while mitigating adverse reactions. Cancer is a series of genetic changes that transform normal cells into tumor cells. These changes come from several reasons, including smoking, drinking alcohol, sunlight, exposure to chemical or physical factors, and finally chronic infection with microorganisms, including bacteria. In fact, bacterial infections are not carcinogenic, but recently it was discovered that the association between bacteria and cancer is through two mechanisms, the first stimulating chronic inflammation and the second producing carcinogenic metabolites. While bacteria are carcinogenic agents also, they have a dual role eliminating and removing tumor cells. However, the traditional cancer treatments that include chemotherapy, radiotherapy, surgery, and immunotherapy increase the chances of survival, and there are many side effects of these therapies, including the high toxicity of tissues and normal cells, could not penetrate the tumor cells, and resistance of these therapies by tumor cells. Therefore, the world has turned to an alternative solution, which is the use of genetically engineered microorganisms; thus, the use of living bacteria targeting cancerous cells is the unique option to overcome these challenges. Bacterial therapies, whether used alone or combination with chemotherapy, give a positive effect to treat multiple conditions of cancer. Also, bacteria can be used as vectors for drug, gene, or therapy, and this is a great step to treat cancer. Thus, we review the mechanisms underlying the interaction of the microbiota residents with cancer. Cancer-associated bacteria differ from those in healthy human and are linked with gene-expression profile. We also discuss how live bacteria interact with tumor microenvironments to induce tumor regression through colonization and spread. Finally, we provide past and ongoing clinical trials that include bacteria targeting tumors.

Compliance, adverse effects and effectiveness of first line bismuth-containing quadruple treatment (Pylera®) to eradicate Helicobacter pylori infection in 200 patients

INTRODUCTION AND OBJECTIVES

quadruple therapy with bismuth is recommended as a first line treatment for Helicobacter pylori (H. pylori) infection. The aim of this study was to evaluate the compliance, adverse effects and effectiveness of this treatment with the new galenic three-in-one capsule formulation containing bismuth subcitrate, metronidazole and tetracycline (Pylera®).

METHODS

a prospective, non-controlled, single center observational study was performed in a cohort of 200 consecutive patients with an untreated H. pylori infection; 58% were female. The subjects were treated for ten days with Pylera® of three capsules four times daily with meals and a proton pump inhibitor taken before breakfast and dinner. The Pylera® capsule contains 140 mg of bismuth subcitrate, 125 mg of metronidazole and 125 mg of tetracycline. The compliance and adverse effects of the treatment were evaluated via telephone contact and via an interview during the clinical revision. Eradication of infection was controlled for at least four weeks after treatment termination via the urea breath test, the stool antigen test with monoclonal antibodies or by histology.

RESULTS

treatment compliance was observed in 96% (192/200) of the patients. Only 28.5% (57/200) of the patients experienced adverse effects, which led to abandoning the treatment in only seven subjects. Severe adverse effects developed in only one case due to Clostridium difficile infection. The effectiveness based on intention to treat was 91.5% (183/200, 95% CI: 87.1-96.8) and per protocol was 95.2% (182/191, 95% CI: 90.9-98.9).

CONCLUSIONS

in our experience, Pylera® is an effective and safe treatment that should be considered as a first line therapeutic option for the eradication of H. pylori infection.

TAZ Controls Helicobacter pylori-Induced Epithelial-Mesenchymal Transition and Cancer Stem Cell-Like Invasive and Tumorigenic Properties

Helicobacter pylori infection, the main risk factor for gastric cancer (GC), leads to an epithelial–mesenchymal transition (EMT) of gastric epithelium contributing to gastric cancer stem cell (CSC) emergence. The Hippo pathway effectors yes-associated protein (YAP) and transcriptional co-activator with PDZ binding motif (TAZ) control cancer initiation and progression in many cancers including GC. Here, we investigated the role of TAZ in the early steps of H. pylori-mediated gastric carcinogenesis. TAZ implication in EMT, invasion, and CSC-related tumorigenic properties were evaluated in three gastric epithelial cell lines infected by H. pylori. We showed that H. pylori infection increased TAZ nuclear expression and transcriptional enhancer TEA domain (TEAD) transcription factors transcriptional activity. Nuclear TAZ and zinc finger E-box-binding homeobox 1 (ZEB1) were co-overexpressed in cells harboring a mesenchymal phenotype in vitro, and in areas of regenerative hyperplasia in gastric mucosa of H. pylori-infected patients and experimentally infected mice, as well as at the invasive front of gastric carcinoma. TAZ silencing reduced ZEB1 expression and EMT phenotype, and strongly inhibited invasion and tumorsphere formation induced by H. pylori. In conclusion, TAZ activation in response to H. pylori infection contributes to H. pylori-induced EMT, invasion, and CSC-like tumorigenic properties. TAZ overexpression in H. pylori-induced pre-neoplastic lesions and in GC could therefore constitute a biomarker of early transformation in gastric carcinogenesis.

The association of Helicobacter pylori CagA EPIYA motifs and vacA genotypes with homologous recombination repair markers during the gastric precancerous cascade

BACKGROUND

Helicobacter pylori-induced DNA damage and impaired homologous recombination repair are vital molecular mechanisms for gastric cancer, which mainly count on its virulence factors cytotoxic-associated gene A (CagA) and vacuolating cytotoxin A (VacA). However, the relationship between H. pylori CagA EPIYA motifs and vacA genotypes with DNA damage and homologous recombination repair markers is still not clear.

METHODS

H. pylori positive and negative gastric biopsies were taken from 165 subjects with different gastric precancerous pathologic stages, and DNA damage marker γH2AX and key homologous recombination repair proteins (CtIP and Rad51) were investigated for their association with H. pylori CagA EPIYA motifs and vacAs-, m-, i-, and d-region genotypes and histology (Sydney classification).

RESULTS

Out of 165 patients, 78 were identified as H. pylori-positive. CagA EPIYA motifs were identified as AB, ABC, and ABD in 2 (3.3%), 21 (35%), and 37 (61.7%) patients, respectively, while vacA alleles were identified as: s1, s2, m1, m2, i1, i2, d1, and d2 in 50 (89.3%), 6 (10.7%), 24 (42.9%), 32 (57.1%), 45 (80.4%), 11 (19.6%), 40 (71.4%), and 16 (28.6%) patients, respectively. vacAs1m1i1d1, s1m2i1d1, and s1m2i2d2 were the most prevailing genotypes. γH2AX was highly localized in H. pylori-positive tissues with corresponding CagA EPIYA motifs and vacA genotypes, while Rad51 and CtIP signals were weak.

CONCLUSION

H. pylori were positively correlated with the DNA damage marker in precancerous lesions, but were negatively correlated with the key homologous recombination repair proteins, which may be due to the specific CagA EPIYA motifs and vacA genotypes.

The Hippo Kinase LATS2 Controls Helicobacter pylori-Induced Epithelial-Mesenchymal Transition and Intestinal Metaplasia in Gastric Mucosa

BACKGROUND & AIMS

Gastric carcinoma is related mostly to CagA+-Helicobacter pylori infection, which disrupts the gastric mucosa turnover and elicits an epithelial-mesenchymal transition (EMT) and preneoplastic transdifferentiation. The tumor suppressor Hippo pathway controls stem cell homeostasis; its core, constituted by the large tumor suppressor 2 (LATS2) kinase and its substrate Yes-associated protein 1 (YAP1), was investigated in this context.

METHODS

Hippo, EMT, and intestinal metaplasia marker expression were investigated by transcriptomic and immunostaining analyses in human gastric AGS and MKN74 and nongastric immortalized RPE1 and HMLE epithelial cell lines challenged by H pylori, and on gastric tissues of infected patients and mice. LATS2 and YAP1 were silenced using small interfering RNAs. A transcriptional enhanced associated domain (TEAD) reporter assay was used. Cell proliferation and invasion were evaluated.

RESULTS

LATS2 and YAP1 appear co-overexpressed in the infected mucosa, especially in gastritis and intestinal metaplasia. H pylori via CagA stimulates LATS2 and YAP1 in a coordinated biphasic pattern, characterized by an early transient YAP1 nuclear accumulation and stimulated YAP1/TEAD transcription, followed by nuclear LATS2 up-regulation leading to YAP1 phosphorylation and targeting for degradation. LATS2 and YAP1 reciprocally positively regulate each other's expression. Loss-of-function experiments showed that LATS2 restricts H pylori-induced EMT marker expression, invasion, and intestinal metaplasia, supporting a role of LATS2 in maintaining the epithelial phenotype of gastric cells and constraining H pylori-induced preneoplastic changes.

CONCLUSIONS

H pylori infection engages a number of signaling cascades that alienate mucosa homeostasis, including the Hippo LATS2/YAP1/TEAD pathway. In the host-pathogen conflict, which generates an inflammatory environment and perturbations of the epithelial turnover and differentiation, Hippo signaling appears as a protective pathway, limiting the loss of gastric epithelial cell identity that precedes gastric carcinoma development.

VacA generates a protective intracellular reservoir for Helicobacter pylori that is eliminated by activation of the lysosomal calcium channel TRPML1

Helicobacter pylori infection is a proven carcinogen for gastric cancer. Its virulence factor vacuolating cytotoxin A (VacA) promotes more severe disease and gastric colonization. VacA, by an unknown mechanism, usurps lysosomal and autophagy pathways to generate a protected reservoir for H. pylori that confers bacterial survival in vitro. Here, we show the existence of a VacA-generated intracellular niche in vivo that protects the bacteria from antibiotic treatment and leads to infection recrudescence after therapy. Furthermore, we report that VacA targets the lysosomal calcium channel TRPML1 to disrupt endolysosomal trafficking and mediate these effects. Remarkably, H. pylori that lack toxigenic VacA colonize enlarged dysfunctional lysosomes in the gastric epithelium of trpml1-null mice, where they are protected from eradication therapy. Furthermore, a small molecule agonist directed against TRPML1 reversed the toxic effects of VacA on endolysosomal trafficking, culminating in the clearance of intracellular bacteria. These results suggest that TRPML1 may represent a therapeutic target for chronic H. pylori infection.

Orthotopic Patient-Derived Xenografts of Gastric Cancer to Decipher Drugs Effects on Cancer Stem Cells and Metastatic Dissemination

Gastric cancer is the third leading cause of cancer mortality worldwide. Cancer stem cells (CSC) are at the origin of tumor initiation, chemoresistance, and the formation of metastases. However, there is a lack of mouse models enabling the study of the metastatic process in gastric adenocarcinoma (GC). The aims of this study were to develop original mouse models of patient-derived primary GC orthotopic xenografts (PDOX) allowing the development of distant metastases as preclinical models to study the anti-metastatic efficiency of drugs such as the phosphatidylinositol 3-kinase (PI3K) inhibitor Buparlisib (BKM120). Luciferase-encoding cells generated from primary GC were injected into the stomach wall of immunocompromised mice; gastric tumor and metastases development were followed by bioluminescence imaging. The anti-CSC properties of BKM120 were evaluated on the GC cells’ phenotype (CD44 expression) and tumorigenic properties in vitro and in vivo on BKM120-treated mice. After eight weeks, PDOX mice formed tumors in the stomach as well as distant metastases, that were enriched in CSC, in the liver, the lung, and the peritoneal cavity. BKM120 treatment significantly inhibited the CSC properties in vitro and reduced the number of distant metastases in mice. These new preclinical models offer the opportunity to study the anti-metastatic efficiency of new CSC-based therapeutic strategies.

Activation of CD3+ T cells by Helicobacter pylori DNA vaccines in potential immunotherapy of gastric carcinoma

Most of gastric carcinoma (GC) is attributed to infection by Helicobacter pylori (H. pylori) but there is increasing evidence that the positive H. pylori status correlates with better prognosis in GC. The H. pylori-induced cellular immune response may suppress cancer and in this work, recombinant pcDNA3 plasmids encoding various fragments of H. pylori virulence genes of cagA, vacA and babA are constructed and combined into groups to immunize BALB/c mice. The activated splenic CD3⁺ T cells are purified and the anticancer effects are investigated in vitro and in vivo. The H. pylori DNA vaccines induce a shift in the response from Th1 to Th2 that mimicks the immune status in patients of GC with chronic H. pylori infection. The stimulated CD3⁺ T cells inhibit the growth of human GC cells in vitro and adoptive transfusions of the CD3⁺ T cells suppress the growth of GC xenograft in vivo. The effects may be caused by the larger ratios of infiltrated CD8⁺/CD4⁺ T cells, reduced infiltration of regulatory FOXP3⁺ T cells, and enhanced apoptosis induced by upregulation of Caspase-9/Caspase-3 and downregulation of Survivin. Our results reveal the potential immunotherapeutic value of H. pylori vaccine-activated CD3⁺ T cells in those with advanced GC.

Efficiency of All-Trans Retinoic Acid on Gastric Cancer: A Narrative Literature Review

Gastric cancer (GC) is the third leading cause of cancer-related death worldwide with a five-year survival rate of around 25%, and 4% when diagnosed at a metastatic stage. Cancer stem cells (CSC) have recently been characterized as being responsible for resistance to radio/chemotherapies and metastasis formation, opening up perspectives for new targeted therapies. Those CSCs express biomarkers such as cluster of differentiation 44 (CD44) and display high aldehyde dehydrogenase activity that converts vitamin A-derived retinal into retinoic acids. All-trans retinoic acid (ATRA), which has pro-differentiating properties, has revolutionized the prognosis of acute promyelotic leukemia by increasing its remission rate from 15% to 85%. Recent studies have started to show that ATRA also has an anti-tumoral role on solid cancers such as GC. The purpose of this review is therefore to summarize the work that evaluated the effects of ATRA in GC and to evaluate whether its anti-cancerous action involves gastric CSCs targeting. It has been demonstrated that ATRA can block the cell cycle, enhance apoptosis, and decrease gastric CSCs properties in GC cell lines, tumorspheres, and patient-derived xenograft mice models. Therefore, retinoids and new synthetic retinoids seem to be a promising step forward in targeted therapy of gastric CSC in combination with existing chemotherapies. Future studies should probably focus on these points.

Acetylcholine induces stem cell properties of gastric cancer cells of diffuse type

Gastric cancer is the third leading cause of cancer-related death worldwide, but the mechanisms of gastric carcinogenesis are not completely understood. Recently, the role of cholinergic neuronal pathways in promoting this process has been demonstrated. Our aim was to extend these studies and to evaluate, using an in vitro model of tumorspheres, the effect of acetylcholine on human gastric cancer cells, and the role of acetylcholine receptors and of the nitric oxide pathway, in this effect. The gastric cancer cell line MKN-45 of the diffuse type of gastric cancer was cultured in the presence of acetylcholine, or different agonists or inhibitors of muscarinic and nicotinic acetylcholine receptors, or nitric oxide donor or inhibitor of the nitric oxide pathway, and the number and size of tumorspheres were assessed. The expression of cancer stem cell markers (CD44 and aldehyde dehydrogenase) was also evaluated by immunofluorescence and quantitative reverse transcription polymerase chain reaction. We showed that acetylcholine increased both the number and size of tumorspheres and that this effect was reproduced with both muscarinic and nicotinic acetylcholine receptors agonists and was inhibited by both receptor antagonists. The nitric oxide donor stimulated the tumorsphere formation, while the nitric oxide synthesis inhibitor inhibited the stimulatory effect of acetylcholine. Moreover, acetylcholine increased the expression of stem cell markers on gastric cancer cells. These results indicate that acetylcholine induces the stem cell properties of gastric cancer cells and both muscarinic and nicotinic receptors and a nitrergic pathway might be involved in this effect.

Helicobacter pylori infection, gestational diabetes mellitus and insulin resistance among pregnant Sudanese women

Objectives

To assess the association between Helicobacter pylori (H. pylori) infection and insulin resistance among pregnant Sudanese women attending Saad Abuelela hospital (Khartoum). A cross-sectional study was conducted from 1st July 2017 to 31st January 2018. One hundred and sixty-six women were enrolled and underwent testing for H. pylori IgG antibodies using specific ELISA kits. The Quantitative insulin sensitivity check index (QUICKI) was computed from the fasting insulin and glucose levels.

Results

Median age, gravidity and gestational age were 27 years, 2 and 26 weeks, respectively. Twenty (12%) women were found to have gestational diabetes mellitus (GDM). H. pylori IgG seroprevalence was 66.0% among the study population. Univariate analysis showed that H. pylori-seropositivity was significantly higher among women who have GDM while Log (Homeostatic Model Assessment-β) HOMA-B% was lower (P value = 0.038, and 0.028) respectively. There was no difference between the GDM group and the other group in terms of demographics, body mass index, haemoglobin and QUICKI index results. In multivariate analysis, a higher prevalence of H. pylori was associated with GDM (OR = 2.8, 95% CI  1.1–7.5, P = 0.036). The current study concludes that an increased prevalence of H. pylori is a risk factor for the development of GDM.

Fas-associated factor 1 inhibits tumor growth by suppressing Helicobacter pylori-induced activation of NF-κB signaling in human gastric carcinoma

Loss of Fas-associated factor 1 (FAF1) may act as a pro-survival signal in diseased cells, but whether this is true in gastric carcinoma remains unclear. Here we report that FAF1 was expressed at low levels in gastric carcinoma tissues and cell lines, and its expression correlated with larger tumors, higher histology grade, higher TNM stage, tumor infiltration, and lymph node metastasis. Univariate analysis and survival curve analysis identified low FAF1 expression as a predictor of poor prognosis. FAF1 overexpression in HGC-27 gastric cancer cells induced cell apoptosis and inhibited cell proliferation and growth. It also reduced colony formation in vitro and tumor growth in mice. We found that Helicobacter pylori, a risk factor for gastric cancer, down-regulated FAF1 expression via NF-κB signaling. Knock-down of IKKβ or p65 expression in gastric cancer cells reversed H. pylori-induced down-regulation of FAF1 expression and partially blocked H. pylori-induced secretion of inflammatory cytokines TNF-α and IL-8. Our results suggest that loss of FAF1 contributes to human gastric carcinogenesis by allowing H. pylori to activate NF-κB signaling.

Genetic diversity and functional analysis of oipA gene in association with other virulence factors among Helicobacter pylori isolates from Iranian patients with different gastric diseases

Helicobacter pylori (H. pylori) is one of the most genetically diverse bacterial pathogens that persistently colonizes the human gastric epithelium. This remarkable genomic plasticity may act as a driving force for successful adaptation and persistence of the bacteria in the harsh gastric environment. Outer inflammatory protein A (OipA) encoded by oipA gene (HP0638/hopH) is a member of the outer membrane proteins (OMPs) of H. pylori involved in induction of IL-8 secretion and is associated with development of peptic ulcer and gastric cancer. Expression of OipA is regulated by phase variation within a CT dinucleotide repeat motif of the oipA gene. In this study we carried out direct DNA sequence analysis of 53 amplified fragments to investigate the oipA "On/Off" status among Iranian H. pylori isolates from patients with various gastric diseases. The prevalence of cagL, cagA, EPIYA motifs, vacA alleles, babA2 and sabA genotypes as well as cagPAI integrity of the isolates were determined by PCR. Our results demonstrated a high prevalence of strains with functional oipA status (79%) and significant associations were found between functional oipA and cagA (P = 0.027) and vacA s1m1 (P = 0.022) genotypes. The vacA s1m2 genotype was also found to be statistically associated with PUD (P = 0.0001). Interestingly, we showed that H. pylori strains with intact cagPAI co-expressed oipA gene in a significant synergistic relationship (P < 0.01). However, no significant association was observed between the functional oipA status and clinical outcomes (P > 0.05). In conclusion, our findings denotes great diversity in the number and pattern of CT dinucleotide repeats of oipA among Iranian H. pylori strains. The synergistic link between functional oipA and other important virulence factors is proposed to be critical in the pathogenesis of H. pylori, which needs further studies with a larger number of samples.

Gastric cancer in Latin America

Every year, cancer affects more than one million Latin Americans. The increasing incidence of cancer could be secondary to an aging population, westernization of life style, and urbanization. LA has among the highest incidence rates of gastric cancer, compared to other countries. In this review, different studies on gastric cancer and its relation with risks factors, such as infections, diet and life styles typical of LA, besides the different molecular alterations of that specific population (mainly at a genetic polymorphism level) are analyzed. An exhaustive research was made in PubMed, MEDLINE and Embase of the most relevant studies conducted in the last 27 years (1990-2017) in LA.

C-C motif chemokine receptors in gastric cancer

Gastric cancer is the fifth most common cancer and the third leading cause of cancer-associated mortality worldwide. Despite recent advances in molecular and clinical research, patients with gastric cancer at an advanced stage have a dismal prognosis and poor survival rates, and systemic treatment relies predominantly on traditional cytotoxic chemotherapy. To improve patients' quality of life and survival, an improved understanding of the complex molecular mechanisms involved in gastric cancer progression and treatment resistance, and of its clinical application in the development of novel targeted therapies, is urgently required. Chemokines are a group of small chemotactic cytokines that interact with seven-transmembrane G-protein-coupled receptors, and this interaction serves a crucial role in various physiological processes, including organ development and the host immune response, to recruit cells to specific sites in the body. There is also accumulating evidence that chemokines and chemokine receptors (CCRs) contribute to tumor development and progression, as well as metastasis. However, research regarding the functional roles of chemokines and their receptors in cancer is dynamic and context-dependent, and much remains to be elucidated, although various aspects have been explored extensively. In gastric cancer, C-C motif CCRs are involved in the biological behavior of tumor cells, including the processes of growth, invasion and survival, as well as the epithelial-mesenchymal transition. In the present review, attention is given to the clinical relevance of C-C motif CCRs in the development, progression, and metastasis of gastric cancer, particularly CCR7 and CCR5, which have been investigated extensively, as well as their potential therapeutic implications.

Promoter methylation of RNF180 is associated with H.pylori infection and serves as a marker for gastric cancer and atrophic gastritis

Promoter methylation (PM) of RING-finger protein (RNF) 180 affects gastric cancer (GC) prognosis, but its association with risk of GC or atrophic gastritis (AG) is unclear. We investigated relationships between RNF180 PM and GC or AG, and the effects of Helicobactor pylori (H.pylori) infection on RNF180 PM. This study included 513 subjects (159 with GC, 186 with AG, and 168 healthy controls [CON]) for RNF180 PM analysis, and another 55 GC patients for RNF180 gene expression analysis. Methylation was quantified using average methylation rates (AMR), methylated CpG site counts (MSC) and hypermethylated CpG site counts (HSC). RNF180 promoter AMR and MSC increased with disease severity. Optimal cut-offs were GC + AG: AMR > 0.153, MSC > 4 or HSC > 1; GC: AMR > 0.316, MSC > 15 and HSC > 6. Hypermethylation at 5 CpG sites differed significantly between GC/AG and CON groups, and was more common in GC patients than AG and CON groups for 2 other CpG sites. The expression of RNF180 mRNA levels in tumor were significantly lower than those in non-tumor, with the same as in hypermethylation than hypomethylation group. H.pylori infection increased methylation in normal tissue or mild gastritis, and increased hypermethylation risk at 3 CpG sites in AG. In conclusion, higher AMR, MSC and HSC levels could identify AG + GC or GC. Some RNF180 promoter CpG sites could identify precancerous or early-stage GC. H.pylori affects RNF180 PM in normal tissue or mild gastritis, and increases hypermethylation in 3 CpG sites in AG.

A Potential New Human Pathogen Belonging to Helicobacter Genus, Identified in a Bloodstream Infection

We isolated from aerobic and anaerobic blood culture bottles from a febrile patient, a Helicobacter-like Gram negative, rod-shaped bacterium that MALDI-TOF MS failed to identify. Blood agar cultures incubated in a microaerobic atmosphere revealed a motile Gram negative rod, which was oxidase, catalase, nitrate reductase, esterase, and alkaline phosphatase positive. It grew at 42°C with no detectable urease activity. Antimicrobial susceptibility testing showed that the organism was susceptible to beta-lactams, gentamicin, erythromycin, and tetracycline but resistant to ciprofloxacin. Electronic microscopy analysis revealed a 3 × 0.5 μm curved rod bacterium harboring two sheathed amphitrichous flagella. Whole genome sequencing revealed a genome 1,708,265 base-pairs long with a GC content of 37.80% and a total of 1,697 coding sequences. The genomic analyses using the nucleotide sequences of the 16S rRNA gene, hsp60 and gyrB genes, as well as the GyrA protein sequence, and the results of Average Nucleotide Identity and in silico DNA-DNA hybridization suggest evidence for a novel Helicobacter species close to Helicobacter equorum and belonging to the group of enterohepatic Helicobacter species. As soon as the particular peptide mass fingerprint of this pathogen is added to the spectral databases, MALDI-TOF MS technology will improve its identification from clinical specimens, especially in case of “sterile infection”. We propose to associate the present strain with the Latin name of the place of isolation; Caesarodunum (Tours, France) and suggest “Helicobacter caesarodunensis” for further description of this new bacterium.

Expression of ERO1L in gastric cancer and its association with patient prognosis

The present study aimed to assess the expression of endoplasmic reticulum oxidoreductin-1-like (ERO1L) in gastric cancer and determine its association with patient prognosis. A total of 105 patients with gastric cancer undergoing radical gastrectomy were selected for the current study. Gastric cancer tissues (the observation group) and normal gastric tissue adjacent to the carcinoma (the control group) were resected from patients. Levels of ERO1L mRNA and protein in tumor tissues and adjacent tissues were detected using reverse transcription-quantitative polymerase chain reaction, western blotting and immunohistochemistry. Patients were divided into two groups: A positive group and negative group, according to the expression of ERO1. The expression of ERO1L in gastric cancer and its association with patient prognosis was analyzed. Levels of ERO1 mRNA and protein in gastric cancer were significantly higher than those of adjacent tissues (P<0.05). Immunohistochemical analysis demonstrated that there were 22 patients exhibiting negative expression of ERO1L and 83 patients exhibiting positive expression of ERO1L. The cumulative recurrence rates over 3 years in patients with positive expression of ERO1L were significantly higher than in patients with negative expression of ERO1L (P<0.05); the cumulative survival rates over 3 years in patients with positive expression of ERO1L were significantly lower than those of patients with negative expression of ERO1L (P<0.05). Thus, the current study determined that ERO1L was highly expressed in gastric cancer tissue. The high expression of ERO1L was associated with adverse prognoses in patients with gastric cancer. ERO1L may therefore be a therapeutic target for the prevention of gastric cancer.

Protein signature characterizing Helicobacter pylori strains of patients with autoimmune atrophic gastritis, duodenal ulcer and gastric cancer

Background

Helicobacter pylori (H. pylori) represents a key factor in the etiology of autoimmune atrophic gastritis (AAG), duodenal ulcer (DU) and gastric cancer (GC). The aim of this study was to characterize the differential protein expression of H. pylori isolated from gastric biopsies of patients affected by either AAG, DU or GC.

Methods

The H. pylori strains were isolated from endoscopic biopsies from the stomach of patients with gastric disease. Protein profiles of H. pylori were compared by two-dimensional difference in gel electrophoresis (2D-DIGE) coupled with mass spectrometry (MS) for the identification of significantly different spots (Student t-test, p < 0.05).

Results

A total of 47 differentially expressed spots were found between H. pylori isolated from patients with either DU or AAG diseases and those isolated from patients with GC (Anova < 0.05, log fold change >1.5). These spots corresponded to 35 unique proteins. The identity of 7 protein spots was validated after one-dimensional electrophoresis and MS/MS analyses of excised gel portions. In H. pylori isolated from DU-patients a significant increase in proteins with antioxidant activity emerged (AroQ, AspA, FldA, Icd, OorA and ScoB), together with a higher content of proteins counteracting the high acid environment (KatA and NapA). In H. pylori isolated from AAG-patients proteins neutralizing hydrogen concentrations through organic substance metabolic processes decreased (GroL, TrxB and Tuf). In addition, a reduction of bacterial motility (FlhA) was found to be associated with AAG-H. pylori isolates. In GC-H. pylori strains it was found an increase in nucleic acid-binding proteins (e.g. DnaG, Tuf, RpoA, RplU) which may be involved in a higher demand of DNA- and protein-related processes.

Conclusion

Our data suggest the presence of specific protein signatures discriminating among H. pylori isolated from either AAG, DU or GC. Changes in protein expression profiles evaluated by DIGE succeeded in deciphering part of the molecular scenarios associated with the different H. pylori-related gastric diseases.

Electronic supplementary material

The online version of this article (doi:10.1186/s13027-017-0133-x) contains supplementary material, which is available to authorized users.

Functional role of autophagy in gastric cancer

Autophagy is a highly regulated catabolic pathway responsible for the degradation of long-lived proteins and damaged intracellular organelles. Perturbations in autophagy are found in gastric cancer. In host gastric cells, autophagy can be induced by Helicobacter pylori (or H. pylori) infection, which is associated with the oncogenesis of gastric cancer. In gastric cancer cells, autophagy has both pro-survival and pro-death functions in determining cell fate. Besides, autophagy modulates gastric cancer metastasis by affecting a wide range of pathological events, including extracellular matrix (ECM) degradation, epithelial-to-mesenchymal transition (EMT), tumor angiogenesis, and tumor microenvironment. In addition, some of the autophagy-related proteins, such as Beclin 1, microtubule-associated protein 1 light chain 3 (MAP1-LC3), and p62/sequestosome 1 (SQSTM1) have certain prognostic values for gastric cancer. In this article, we review the recent studies regarding the functional role of autophagy in gastric cancer.

The internalization of Helicobacter pylori plays a role in the failure of H. pylori eradication

BACKGROUND

Helicobacter pylori (H. pylori) internalization involves invasion of cells by the bacterium. Several studies have shown that H. pylori can invade human gastric epithelial cells, immune cells, and Candida yeast in vivo and in vitro. Whether bacterial invasion plays a role in eradication failure is unclear.

AIM

To investigate the relationship between H. pylori invasion of GES-1 cells and H. pylori eradication failure.

MATERIALS AND METHODS

Forty-two clinical strains isolated from H. pylori-positive patients with different outcomes after treatment with furazolidone-based therapy were examined (17 failures and 25 successes). The H. pylori strains were shown to be susceptible to amoxicillin and furazolidone, and the patients also exhibited good compliance. Genotyping was performed for cagA and vacA (s and m). The antibiotic susceptibility of the strains to amoxicillin, furazolidone, clarithromycin, metronidazole, and levofloxacin was determined by E-tests. The levels of H. pylori invasion of GES-1 cells were detected by gentamicin colony-forming unit assays.

RESULTS

The internalization level in the eradication success group was 5.40±5.78 × 10^-3  cfu/cell, and the median was 6.194 × 10^-3  cfu/cell; the internalization level in the eradication failure group was 8.98±5.40 × 10^-3  cfu/cell, and the median was 10.28 × 10^-3  cfu/cell. The eradication failure group showed a greater invasion level than the eradication success group (P<.05). No significant difference was observed between the susceptible strains and the resistant strains when the internalization levels were compared (P>.05).

CONCLUSIONS

The results showed that H. pylori invasion of the gastric epithelia might play a role in eradication failure.

A Strategy for Helicobacter Immunohistochemistry Utilization in Pediatric Practice: Insights From Morphologic and Cost-Benefit Analyses

OBJECTIVES

Recent studies in adults have examined the utility of immunohistochemistry (IHC) in detecting Helicobacter in gastric biopsy specimens and reached differing conclusions. Dedicated cost-benefit analysis of Helicobacter IHC in pediatric gastric biopsy specimens has not been performed.

METHODS

From 1,955 pediatric gastric biopsies in a 1-year period, we identified 63 Helicobacter -positive and 120 Helicobacter -negative biopsy specimens. All cases were scored according to the Updated Sydney System for the severity of inflammation.

RESULTS

We observed that pediatric Helicobacter infection was significantly associated with germinal center formation, active inflammation, oxyntic mucosa with moderate to severe chronic inflammation, and antral mucosa with any chronic inflammation, exclusive of mild and superficial chronic inflammation. At least one associated pattern was seen in each Helicobacter -positive biopsy specimen. In comparison with adults, pediatric Helicobacter -positive biopsy specimens are more likely to lack acute inflammation and more likely to show moderate to marked chronic inflammation.

CONCLUSIONS

We recommend performing Helicobacter IHC on pediatric gastric biopsy specimens with any of the above inflammatory patterns. This approach can sensitively identify pediatric patients with Helicobacter gastritis, limit IHC staining to approximately 30% of all gastric biopsy specimens, and reduce costs by up to $55,306.90 per 1,000 biopsy specimens.

Characterization of Biomarkers of Tumorigenic and Chemoresistant Cancer Stem Cells in Human Gastric Carcinoma

Purpose: Gastric carcinomas are heterogeneous, and the current therapy remains essentially based on surgery with conventional chemotherapy and radiotherapy. This study aimed to characterize biomarkers allowing the detection of cancer stem cells (CSC) in human gastric carcinoma of different histologic types.Experimental Design: The primary tumors from 37 patients with intestinal- or diffuse-type noncardia gastric carcinoma were studied, and patient-derived tumor xenograft (PDX) models in immunodeficient mice were developed. The expressions of 10 putative cell surface markers of CSCs, as well as aldehyde dehydrogenase (ALDH) activity, were studied, and the tumorigenic properties of cells were evaluated by in vitro tumorsphere assays and in vivo xenografts by limiting dilution assays.Results: We found that a subpopulation of gastric carcinoma cells expressing EPCAM, CD133, CD166, CD44, and a high ALDH activity presented the properties to generate new heterogeneous tumorspheres in vitro and tumors in vivo CD44 and CD166 were coexpressed, representing 6.1% to 37.5% of the cells; ALDH activity was detected in 1.6% to 15.4% of the cells; and the ALDH⁺ cells represented a core within the CD44⁺/CD166⁺ subpopulation that contained the highest frequency of tumorigenic CSCs in vivo The ALDH⁺ cells possessed drug efflux properties and were more resistant to standard chemotherapy than the ALDH^- cells, a process that was partially reversed by verapamil treatment.Conclusions: CD44 and ALDH are the most specific biomarkers to detect and isolate tumorigenic and chemoresistant gastric CSCs in noncardia gastric carcinomas independently of the histologic classification of the tumor. Clin Cancer Res; 23(6); 1586-97. ©2016 AACR.

Lipopolysaccharide modification in Gram-negative bacteria during chronic infection

The Gram-negative bacterial lipopolysaccharide (LPS) is a major component of the outer membrane that plays a key role in host-pathogen interactions with the innate immune system. During infection, bacteria are exposed to a host environment that is typically dominated by inflammatory cells and soluble factors, including antibiotics, which provide cues about regulation of gene expression. Bacterial adaptive changes including modulation of LPS synthesis and structure are a conserved theme in infections, irrespective of the type or bacteria or the site of infection. In general, these changes result in immune system evasion, persisting inflammation and increased antimicrobial resistance. Here, we review the modifications of LPS structure and biosynthetic pathways that occur upon adaptation of model opportunistic pathogens (Pseudomonas aeruginosa, Burkholderia cepacia complex bacteria, Helicobacter pylori and Salmonella enterica) to chronic infection in respiratory and gastrointestinal sites. We also discuss the molecular mechanisms of these variations and their role in the host-pathogen interaction.

All-trans retinoic acid targets gastric cancer stem cells and inhibits patient-derived gastric carcinoma tumor growth

Gastric carcinoma is the third leading cause of cancer-related death worldwide. This cancer, most of the time metastatic, is essentially treated by surgery associated with conventional chemotherapy, and has a poor prognosis. The existence of cancer stem cells (CSC) expressing CD44 and a high aldehyde dehydrogenase (ALDH) activity has recently been demonstrated in gastric carcinoma and has opened new perspectives to develop targeted therapy. In this study, we evaluated the effects of all-trans-retinoic acid (ATRA) on CSCs in human gastric carcinoma. ATRA effects were evaluated on the proliferation and tumorigenic properties of gastric carcinoma cells from patient-derived tumors and cell lines in conventional 2D cultures, in 3D culture systems (tumorsphere assay) and in mouse xenograft models. ATRA inhibited both tumorspheres initiation and growth in vitro, which was associated with a cell-cycle arrest through the upregulation of cyclin-dependent kinase (CDK) inhibitors and the downregulation of cell-cycle progression activators. More importantly, ATRA downregulated the expression of the CSC markers CD44 and ALDH as well as stemness genes such as Klf4 and Sox2 and induced differentiation of tumorspheres. Finally, 2 weeks of daily ATRA treatment were sufficient to inhibit gastric tumor progression in vivo, which was associated with a decrease in CD44, ALDH1, Ki67 and PCNA expression in the remaining tumor cells. Administration of ATRA appears to be a potent strategy to efficiently inhibit tumor growth and more importantly to target gastric CSCs in both intestinal and diffuse types of gastric carcinoma.

Expression of cagA, virB/D Complex and/or vacA Genes in Helicobacter pylori Strains Originating from Patients with Gastric Diseases

In order to better understand pathogenicity of Helicobacter pylori, particularly in the context of its carcinogenic activity, we analysed expression of virulence genes: cagA, virB/D complex (virB4, virB7, virB8, virB9, virB10, virB11, virD4) and vacA in strains of the pathogen originating from persons with gastric diseases. The studies were conducted on 42 strains of H. pylori isolated from patients with histological diagnosis of non-atrophic gastritis—NAG (group 1, including subgroup 1 containing cagA⁺ isolates and subgroup 2 containing cagA^- strains), multifocal atrophic gastritis—MAG (group 2) and gastric adenocarcinoma—GC (group 3). Expression of H. pylori genes was studied using microarray technology. In group 1, in all strains of H. pylori cagA⁺ (subgroup 1) high expression of the gene as well as of virB/D was disclosed, accompanied by moderate expression of vacA. In strains of subgroup 2 a moderate expression of vacA was detected. All strains in groups 2 and 3 carried cagA gene but they differed in its expression: a high expression was detected in isolates of group 2 and its hyperexpression in strains of group 3 (hypervirulent strains). In both groups high expression of virB/D and vacA was disclosed. Our results indicate that chronic active gastritis may be induced by both cagA⁺ strains of H. pylori, manifesting high expression of virB/D complex but moderate activity of vacA, and cagA^- strains with moderate expression of vacA gene. On the other hand, in progression of gastric pathology and carcinogenesis linked to H. pylori a significant role was played by hypervirulent strains, manifesting a very high expression of cagA and high activity of virB/D and vacA genes.

Noncoding Genomics in Gastric Cancer and the Gastric Precancerous Cascade: Pathogenesis and Biomarkers

Gastric cancer is the fifth most common cancer and the third leading cause of cancer-related death, whose patterns vary among geographical regions and ethnicities. It is a multifactorial disease, and its development depends on infection by Helicobacter pylori (H. pylori) and Epstein-Barr virus (EBV), host genetic factors, and environmental factors. The heterogeneity of the disease has begun to be unraveled by a comprehensive mutational evaluation of primary tumors. The low-abundance of mutations suggests that other mechanisms participate in the evolution of the disease, such as those found through analyses of noncoding genomics. Noncoding genomics includes single nucleotide polymorphisms (SNPs), regulation of gene expression through DNA methylation of promoter sites, miRNAs, other noncoding RNAs in regulatory regions, and other topics. These processes and molecules ultimately control gene expression. Potential biomarkers are appearing from analyses of noncoding genomics. This review focuses on noncoding genomics and potential biomarkers in the context of gastric cancer and the gastric precancerous cascade.