Helicobacter pylori CagA and gastric cancer: a paradigm for hit-and-run carcinogenesis. Cell Host Microbe. 2014;15:306-316. [PMID: 24629337 DOI: 10.1016/j.chom.2014.02.008]

Natural small-molecule compounds targeting Helicobacter pylori virulence factors: A promising strategy for overcoming antibiotic resistance

Helicobacter pylori (H. pylori) infection is an important causal factor of gastritis, peptic ulcer, and gastric cancer. High infection rates and the increasing challenge of antibiotic resistance worldwide have prompted an urgent need to develop novel therapeutic options and antimicrobial agents. This review focuses on the potential of natural small-molecule compounds as novel anti-H. pylori agents-a promising approach that mitigates the risk of resistance development and maintains the microbiome's ecological balance. We detail how H. pylori virulence factors, including urease, CagA, VacA, and biofilm, contribute to pathogenicity and underline the reassuring fact that naturally derived compounds sourced from plants and microorganisms have shown remarkable efficacy in inhibiting these virulence factors. Some compounds also exhibit synergistic effects with conventional antibiotics, potentially overcoming challenges associated with resistant strains. Furthermore, we discuss recent advancements in identifying novel drug targets within the H. pylori virulence spectrum, offering insights into future directions for research and development in H. pylori therapy.

Helicobacter pylori CagA and CagT antibodies arrest the translocation of CagA into gastric epithelial cells

Cytotoxic-associated gene A (CagA) is a key virulence factor of Helicobacter pylori, associated with gastric ulcers and stomach cancer. The bacterium employs a Cag-type IV secretion system for translocation of CagA into the host cells. This study investigates the impact of CagA antibodies on CagA translocation into gastric epithelial cells in vitro. Our findings reveal that CagA synthesis and translocation across bacterial membranes is a continuous process initiated upon host-cell contact. Notably, the treatment of Helicobacter pylori with CagA-specific antibodies significantly inhibited the translocation of CagA into host cells during infection. These results suggest that the CagA antibody may serve as a potential therapeutic strategy to combat Helicobacter pylori pathogenesis. A similar result was obtained when CagT antibody was used under the same conditions. Notably, the CagT antibody exhibited a more pronounced pathoblocking effect, likely due to its accessibility on the bacterial surface as a structural component of Cag-T4SS. Taken together, this study provides insights into the therapeutic potential of CagA and CagT antibodies to mitigate Helicobacter pylori infection, while also advancing our understanding of the mechanisms involved in CagA translocation across the bacterial membranes to the host cell.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-025-04343-0.

Biofilm formation by the host microbiota: a protective shield against immunity and its implication in cancer

Human-resident microbes typically cluster into biofilms - structurally organized communities embedded within a matrix of self-produced extracellular polymeric substance (EPS) that serves as a protective shield. These biofilms enhance microbial survival and functional adaptability, favoring a symbiotic relationship with the host under physiological conditions. However, biofilms exhibit a dual role in modulating the immune response. If their ability to promote tolerance is key to safeguarding homeostasis, by contrast, their persistence can overcome the cutting-edge balance resulting in immune evasion, chronic inflammation and development of numerous diseases such as cancer. Recent evidence highlights the significance of cancer-associated microbiota in shaping the tumor microenvironment (TME). These microbial inhabitants often exhibit biofilm-like structures, which may protect them from host immune responses and therapeutic interventions. The presence of biofilm-forming microbiota within the TME may promote chronic inflammation, and release of bioactive molecules that interfere with immune surveillance mechanisms, thereby enabling cancer cells to evade immune destruction. This review delves into the complex interplay between biofilms and cancer, with particular focus on the tumor-associated microbiota and the implications of biofilm involvement in modulating the immune landscape of the TME. Addressing this intricate relationship holds promises for innovative therapeutic approaches aimed at reprogramming the microbiota-cancer axis for better clinical outcomes.

Species-specific components of the Helicobacter pylori Cag type IV secretion system

Helicobacter pylori strains containing the cag pathogenicity island (PAI) deliver an effector protein (CagA) and non-protein substrates into gastric cells through a process that requires the Cag type IV secretion system (T4SS). The Cag T4SS outer membrane core complex (OMCC) contains multiple copies of five proteins, two of which are species-specific proteins. By using modifications of a previously described OMCC immunopurification method and optimized mass spectrometric methods, we have now isolated additional cag PAI-encoded proteins that are present in lower relative abundance. Four of these proteins (CagW, CagL, CagI, and CagH) do not exhibit sequence relatedness to T4SS components in other bacterial species. Size exclusion chromatography analysis of immunopurified samples revealed that CagW, CagL, CagI, and CagH co-elute with OMCC components. These four Cag proteins are copurified with the OMCC in immunopurifications from a Δcag3 mutant strain (lacking peripheral OMCC components), but not from a ΔcagX mutant strain (defective in OMCC assembly). Negative stain electron microscopy analysis indicated that OMCC preparations isolated from ΔcagW, cagL::kan, ΔcagI, and ΔcagH mutant strains are indistinguishable from wild-type OMCCs. In summary, by using several complementary methods, we have identified multiple species-specific Cag proteins that are associated with the Cag T4SS OMCC and are required for T4SS activity.

Macrophage biology in the pathogenesis of Helicobacter pylori infection

Infection with H. pylori induces chronic gastric inflammation, progressing to peptic ulcer and stomach adenocarcinoma. Macrophages function as innate immune cells and play a vital role in host immune defense against bacterial infection. However, the distinctive mechanism by which H. pylori evades phagocytosis allows it to colonize the stomach and further aggravate gastric preneoplastic pathology. H. pylori exacerbates gastric inflammation by promoting oxidative stress, resisting macrophage phagocytosis, and inducing M1 macrophage polarization. M2 macrophages facilitate the proliferation, invasion, and migration of gastric cancer cells. Various molecular mechanisms governing macrophage function in the pathogenesis of H. pylori infection have been identified. In this review, we summarize recent findings of macrophage interactions with H. pylori infection, with an emphasis on the regulatory mechanisms that determine the clinical outcome of bacterial infection.

Helicobacter pylori, microbiota and gastric cancer - principles of microorganism-driven carcinogenesis

The demonstration that Helicobacter pylori is a pathogenic bacterium with marked carcinogenic potential has paved the way for new preventive approaches for gastric cancer. Although decades of research have uncovered complex interactions of H. pylori with epithelial cells, current insights have refined our view on H. pylori-associated carcinogenesis. Specifically, the cell-type-specific effects on gastric stem and progenitor cells deep in gastric glands provide a new view on the ability of the bacteria to colonize long-term, manipulate host responses and promote gastric pathology. Furthermore, new, large-scale epidemiological data have shed light on factors that determine why only a subset of carriers progress to gastric cancer. Currently, technological advances have brought yet another revelation: H. pylori is far from the only microorganism able to colonize the stomach. Instead, the stomach is colonized by a diverse gastric microbiota, and there is emerging evidence for the occurrence and pathological effect of dysbiosis resulting from an aberrant interplay between H. pylori and the gastric mucosa. With the weight of this evidence mounting, here we consider how the lessons learned from H. pylori research inform and synergize with this emerging field to bring a more comprehensive understanding of the role of microbes in gastric carcinogenesis.

Helicobacter pylori CagA elevates FTO to induce gastric cancer progression via a "hit-and-run" paradigm

BACKGROUND

Helicobacter pylori (H. pylori) infection contributes significantly to gastric cancer (GC) progression. The intrinsic mechanisms of H. pylori-host interactions and their role in promoting GC progression need further investigation. In this study, we explored the potential role of fat mass and obesity-associated protein (FTO) in mediating Cytotoxin-associated gene A (CagA)-induced GC progression.

METHODS

The effects of H. pylori infection on N6-methyladenosine (m6A) modification were evaluated in both human samples and GC cell lines. The function of FTO in the progression of GC was elucidated through in vitro and in vivo studies. A series of techniques, including methylated RNA immunoprecipitation sequencing, RNA sequencing, RNA binding protein immunoprecipitation, and chromatin immunoprecipitation assays, were utilized to investigate the mechanism by which FTO mediates the capacity of cagA-positive H. pylori to promote GC progression. Furthermore, the therapeutic potential of the FTO inhibitor meclofenamic acid (MA) in impeding GC progression was evaluated across GC cells, animal models, and human GC organoids.

RESULTS

Infection with cagA-positive H. pylori upregulated the expression of FTO, which was essential for CagA-mediated GC metastasis and significantly associated with a poor prognosis in GC patients. Mechanistically, CagA delivered by H. pylori enhanced FTO transcription via Jun proto-oncogene. Elevated FTO induced demethylation of m6A and inhibited the degradation of heparin-binding EGF-like growth factor (HBEGF), thereby facilitating the epithelial-mesenchymal transition (EMT) process in GC cells. Interestingly, eradication of H. pylori did not fully reverse the increases in FTO and HBEGF levels induced by cagA-positive H. pylori. However, treatment with a combination of antibiotics and MA substantially inhibited cagA-positive H. pylori-induced EMT and prevented GC metastasis.

CONCLUSION

Our study revealed that FTO mediates the "hit-and-run" mechanism of CagA-induced GC progression, which suggests that the therapeutic targeting of FTO could offer a promising approach to the prevention of CagA-induced cancer progression.

Genome-wide accumulations of non-random adaptive point mutations drive westward evolution of Helicobacter pylori

BACKGROUND

For last seven decades we remained convinced that the natural point mutations occur randomly in the genome of an organism. However, our whole genome sequence analyses show that for the gastric pathogen Helicobacter pylori, which causes peptic ulcer and gastric cancer, accumulations of point mutations in the genome are non-random and they contribute to its unidirectional evolution. Based on the oncoprotein CagA, the pathogen can be classified into Eastern (East Asian countries like China and Japan; high incidence of gastric cancer) and Western (Europe, Africa, South-West Asian countries like India; low incidence of gastric cancer) types.

RESULTS

We have found a unique high-altitude Himalayan region, Sikkim (an Indian state bordering China, Nepal and Bhutan), where the evolving Eastern and Western H. pylori types co-exist and show the signs of genetic admixtures. Here, we present genomic evidence for more virulent Eastern-H. pylori getting converted to less virulent Western-H. pylori by accumulating non-random adaptive point mutations.

CONCLUSION

The lesser virulence of the westernized H. pylori is beneficial since this pathogen typically remains colonized in the stomach for decades before causing terminal diseases like gastric cancer. Moreover, the mutation-driven westward evolution of H. pylori is a global phenomenon, which occurred in the geographical regions where people from Eastern and Western ethnicities met and cohabited. The identified evolution of virulent Eastern H. pylori strains to lesser virulent Western variants by accumulation of point mutations also provides insight into the pathogenic potentials of different H. pylori strains.

Helicobacter pylori CagA and Cag type IV secretion system activity have key roles in triggering gastric transcriptional and proteomic alterations

Colonization of the human stomach with cag pathogenicity island (PAI)-positive Helicobacter pylori strains is associated with increased gastric cancer risk compared to colonization with cag PAI-negative strains. To evaluate the contributions of the Cag type IV secretion system (T4SS) and CagA (a secreted bacterial oncoprotein) to gastric molecular alterations relevant for carcinogenesis, we infected Mongolian gerbils with a Cag T4SS-positive wild-type (WT) H. pylori strain, one of two Cag T4SS mutant strains (∆cagT or ∆cagY), or a ∆cagA mutant for 12 weeks. Histologic staining revealed a biphasic distribution of gastric inflammation severity in WT-infected animals and minimal inflammation in animals infected with mutant strains. Atrophic gastritis (a premalignant condition), dysplasia, and gastric adenocarcinoma were only detected in WT-infected animals with high inflammation scores. Transcriptional profiling, liquid chromatography-tandem mass spectrometry analysis of micro-extracted tryptic peptides, and imaging mass spectrometry revealed more than a thousand molecular alterations in gastric tissues from WT-infected animals with high inflammation scores compared to uninfected tissues and few alterations in tissues from other groups of infected animals. Proteins with altered abundance in animals with severe Cag T4SS-induced inflammation mapped to multiple pathways, including the complement/coagulation cascade and proteasome pathway. Proteins exhibiting markedly increased abundance in tissues from H. pylori-infected animals with severe inflammation included calprotectin components, proteins involved in proteasome activation, polymeric immunoglobulin receptor (PIGR), interferon-inducible guanylate-binding protein (GBP2), lactoferrin, lysozyme, superoxide dismutase, and eosinophil peroxidase. These results demonstrate key roles for CagA and Cag T4SS activity in promoting gastric mucosal inflammation, transcriptional alterations, and proteomic alterations relevant to gastric carcinogenesis.IMPORTANCEHelicobacter pylori colonizes the stomachs of about half of humans worldwide, and its presence is the primary risk factor for the development of stomach cancer. H. pylori strains isolated from humans can be broadly classified into two groups based on whether they contain a chromosomal cag pathogenicity island, which encodes a secreted effector protein (CagA) and components of a type IV secretion system (T4SS). In experiments using a Mongolian gerbil model, we found that severe gastric inflammation and gastric transcriptional and proteomic alterations related to gastric cancer development were detected only in animals infected with a wild-type H. pylori strain containing CagA and an intact Cag T4SS. Mutant strains lacking CagA or Cag T4SS activity successfully colonized the stomach without inducing detectable pathologic host responses. These findings illustrate two different patterns of H. pylori-host interaction.

Heterogeneity of T cells regulates tumor immunity mediated by Helicobacter pylori infection in gastric cancer

The impact of Helicobacter pylori (H. pylori) status on gastric cancer survival remains unclear. In this study, we conducted a prognostic analysis of 488 gastric cancer patients and performed single-cell RNA sequencing (scRNA-seq) on 18,717 T cells from six tumor samples with varying H. pylori statuses. Our findings revealed that gastric cancer patients with H. pylori infection had significantly longer survival times compared to those with negative H. pylori status. After unsupervised re-clustering of T cells based on scRNA-seq data, we identified ten CD4+ and twelve CD8+ clusters. Among them, four CD8+ T cell clusters exhibited distinct distributions based on H. pylori infection status. One cluster, marked by CXCL13, showed high levels of IFNG and GZMB in H. pylori-infected patients, while another cluster, which expressed immune suppression related genes like AREG and PTGER2, was predominantly comprised of cells from non-infected patients. High PTGER2 expression was significantly associated with worse prognosis in patients with high CD8 expression. These insights advance our understanding of H. pylori's influence on T cell responses in gastric cancer, aiding in treatment and prognostic strategies.

Recent advances in the mechanisms of PD-L1 expression in gastric cancer: a review

In the progression of gastric cancer (GC), various cell types in the tumor microenvironment (TME) exhibit upregulated expression of programmed death ligand 1 (PD-L1), leading to impaired T-cell function and evasion of immune surveillance. Infection with H. pylori and EBV leads to increased PD-L1 expression in various cell types within TME, resulting in immune suppression and facilitating immune escape of GC cells. In the TME, mesenchymal stem cells (MSCs), M1-like tumor-associated macrophages (MI-like TAM), and myeloid-derived suppressor cells (MDSCs) contribute to the upregulation of PD-L1 expression in GC cells. Conversely, mast cells, M2-like tumor-associated macrophages (M2-like TAM), and tumor-associated neutrophils (TANs) exhibit elevated levels of PD-L1 expression in response to the influence of GC cells. Together, these factors collectively contribute to the upregulation of PD-L1 expression in GC. This review aims to provide a comprehensive summary of the cellular expression patterns of PD-L1 in GC and the underlying molecular mechanisms. Understanding the complex regulatory pathways governing PD-L1 expression may offer novel insights for the development of effective immunotherapeutic interventions.

Helicobacter pylori virulence factor CagA promotes Snail-mediated epithelial-mesenchymal transition and invasive behavior by downregulating Semaphorin 5A in gastric epithelial cells

Helicobacter pylori (H. pylori) infection is one of the major risk factors of stomach cancer. Strains carrying the oncogenic cytotoxin CagA (cytotoxin-associated gene A) induce epithelial-mesenchymal transition (EMT) and contribute to tumor progression and metastasis. However, the mechanism in which CagA induces EMT has not been defined. In this study, using genetic methods in Drosophila, we identified Semaphorin 5A (SEMA5A) as a new target for CagA. We showed that infection with CagA-positive H. pylori downregulated the expression level of SEMA5A to induce expression of EMT-driving transcription factor Snail and mesenchymal marker N-cadherin, and promote invasive behavior in gastric epithelial cells. Furthermore, we demonstrated that transient over-expression of SEMA5A in H. pylori-infected cells inhibited CagA-mediated gain of mesenchymal phenotype. These results suggest that SEMA5A could be a key mediator of EMT and gastric carcinogenesis caused by CagA-positive H. pylori infection.

The landcape of Helicobacter pylori-mediated DNA breaks links bacterial genotoxicity to its oncogenic potential

BACKGROUND

Helicobacter pylori (H. pylori) infection is a significant risk factor for gastric cancer (GC) development. A growing body of evidence suggests a causal link between infection with H. pylori and increased DNA breakage in the host cells. While several mechanisms have been proposed for this damage, their relative impact on the overall bacterial genotoxicity is unknown. Moreover, the link between the formation of DNA damage following infection and the emergence of cancerous structural variants (SV) in the genome of infected cells remained unexplored.

METHODS

We constructed a high-resolution map of genomic H. pylori-induced recurrent break sites using the END-seq method on AGS human gastric cells before and after infection. We next applied END-seq to cycling and arrested cells to identify the role of DNA replication on break formation. Recurrent H. pylori-mediated break sites were further characterized by analyzing published RNA-seq, DRIP-seq, and GRO-seq data at these sites. γH2AX staining and comet assay were used for DNA breakage quantification. Liquid chromatography-mass spectrometry (LC-MS) assay was used to quantify cellular concentrations of dNTPs.

RESULTS

Our data indicated that sites of recurrent H. pylori-mediated DNA breaks are ubiquitous across cell types, localized at replication-related fragile sites, and their breakage is dependent on replication. Consistent with that, we found that H. pylori inflicts nucleotide depletion, and that rescuing the cellular nucleotide pool largely reduced H. pylori-induced DNA breaks. Intriguingly, we found that this genotoxic mechanism operates independently of H. pylori cag pathogenicity island (CagPAI) that encodes for the bacterial type 4 secretion system (T4SS), and its virulence factor, CagA, which was previously implicated in increasing DNA damage by downregulating the DNA damage response. Finally, we show that sites of recurrent H. pylori-mediated breaks coincide with chromosomal deletions observed in patients with intestinal-type GC and that this link potentially elucidates the persistent transcriptional alterations observed in cancer driver genes.

CONCLUSIONS

Our findings indicate that dNTP depletion by H. pylori is a key component of its genotoxicity and suggest a link between H. pylori genotoxicity and its oncogenic potential.

Immunoinformatic strategy for developing multi-epitope subunit vaccine against Helicobacter pylori

Helicobacter pylori is a gram-negative bacterium that persistently infects the human stomach, leading to peptic ulcers, gastritis, and an increased risk of gastric cancer. The extremophilic characteristics of this bacterium make it resistant to current drug treatments, and there are no licensed vaccines available against H. pylori. Computational approaches offer a viable alternative for designing antigenic, stable, and safe vaccines to control infections caused by this pathogen. In this study, we employed an immunoinformatic strategy to design a set of candidate multi-epitope subunit vaccines by combining the most potent B and T cell epitopes from three targeted antigenic proteins (BabA, CagA, and VacA). Out of the 12 hypothetical vaccines generated, two (HP_VaX_V1 and HP_VaX_V2) were found to be strongly immunogenic, non-allergenic, and structurally stable. The proposed vaccine candidates were evaluated based on population coverage, molecular docking, immune simulations, codon adaptation, secondary mRNA structure, and in silico cloning. The vaccine candidates exhibited antigenic scores of 1.19 and 1.01, with 93.5% and 90.4% of the most rama-favored regions, respectively. HP_VaX_V1 and HP_VaX_V2 exhibited the strongest binding affinity towards TLR-7 and TLR-8, as determined by molecular docking simulations (ΔG = -20.3 and -20.9, respectively). Afterward, multi-scale normal mode analysis simulation revealed the structural flexibility and stability of vaccine candidates. Additionally, immune simulations showed elevated levels of cell-mediated immunity, while repeated exposure simulations indicated rapid antigen clearance. Finally, in silico cloning was performed using the expression vector pET28a (+) with optimized restriction sites to develop a viable strategy for large-scale production of the chosen vaccine constructs. These analyses suggest that the proposed vaccines may elicit potent immune responses against H. pylori, but laboratory validation is needed to verify their safety and immunogenicity.

Microbial molecules, metabolites, and malignancy

Research elucidating the role of the microbiome in carcinogenesis has grown exponentially over the past decade. Initially isolated to associative studies on colon cancer development, the field has expanded to encompass nearly every solid and liquid malignancy that may afflict the human body. Investigations are rapidly progressing from association to causation and one particular area of causal effect relates to microbial metabolites and how they influence cancer development, progression, and treatment response. These metabolites can be produced de novo from individual members of the microbiome, whether that be bacteria, fungi, archaea, or other microbial organisms, or they can be through metabolic processing of dietary compounds or even host-derived molecules. In this review, contemporary research elucidating mechanisms whereby microbial-derived molecules and metabolites impact carcinogenesis and cancer treatment efficacy will be presented. While many of the examples focus on bacterial metabolites in colon carcinogenesis, this simply illustrates the accelerated nature of these investigations that occurred early in microbiome research but provides an opportunity for growth in other cancer areas. Indeed, research into the interaction of microbiome-derived metabolites in other malignancies is growing as well as investigations that involve non-bacterial metabolites. This review will provide the reader a framework to expand their knowledge regarding this complex and exciting field of cancer research.

H. Pylori-Facilitated TERT/Wnt/β-Catenin Triggers Spasmolytic Polypeptide-Expressing Metaplasia and Oxyntic Atrophy

Persistent H. pylori infection triggers the repair program of the mucosa, such as spasmolytic polypeptide-expressing metaplasia (SPEM). However, the mechanism underlying the initiation of SPEM in gastric tissues by H. pylori remains unclear. Here, an increase in telomerase reverse transcriptase (TERT) protein expression is observed in chief cells upon infection with cagA-positive H. pylori. Tert knockout significantly ameliorated H. pylori-induced SPEM and single-cell RNA sequencing demonstrated that the Wnt/β-Catenin pathway is suppressed in gastric cells with Tert knockout. Mechanism study revealed that CagA elevated TERT abundance by disrupting the interaction between TERT and its novel E3 ligase, SYVN1. Interestingly, Nitazoxanide effectively relieved SPEM via inhibition of the Wnt/β-Catenin signaling in vivo. This results clarified the mechanism underlying which CagA activated the TERT/Wnt/β-Catenin pathway, thus promoting the dedifferentiation of chief cells and the occurrence of SPEM in gastric mucosa. This highlights a molecular basis for targeting CagA-activated Wnt signaling in chief cells for the treatment of gastric precancerous lesions.

The Influence of Gastric Microbiota and Probiotics in Helicobacter pylori Infection and Associated Diseases

The role of microbiota in human health and disease is becoming increasingly clear as a result of modern microbiome studies in recent decades. The gastrointestinal tract is the major habitat for microbiota in the human body. This microbiota comprises several trillion microorganisms, which is equivalent to almost ten times the total number of cells of the human host. Helicobacter pylori is a known pathogen that colonizes the gastric mucosa of almost half of the world population. H. pylori is associated with several gastric diseases, including gastric cancer (GC) development. However, the impact of the gastric microbiota in the colonization, chronic infection, and pathogenesis is still not fully understood. Several studies have documented qualitative and quantitative changes in the microbiota's composition in the presence or absence of this pathogen. Among the diverse microflora in the stomach, the Firmicutes represent the most notable. Bacteria such as Prevotella sp., Clostridium sp., Lactobacillus sp., and Veillonella sp. were frequently found in the healthy human stomach. In contrast, H.pylori is very dominant during chronic gastritis, increasing the proportion of Proteobacteria in the total microbiota to almost 80%, with decreasing relative proportions of Firmicutes. Likewise, H. pylori and Streptococcus are the most abundant bacteria during peptic ulcer disease. While the development of H. pylori-associated intestinal metaplasia is accompanied by an increase in Bacteroides, the stomachs of GC patients are dominated by Firmicutes such as Lactobacillus and Veillonella, constituting up to 40% of the total microbiota, and by Bacteroidetes such as Prevotella, whereas the numbers of H. pylori are decreasing. This review focuses on some of the consequences of changes in the gastric microbiota and the function of probiotics to modulate H. pylori infection and dysbiosis in general.

T4SEpp: A pipeline integrating protein language models to predict bacterial type IV secreted effectors

Many pathogenic bacteria use type IV secretion systems (T4SSs) to deliver effectors (T4SEs) into the cytoplasm of eukaryotic cells, causing diseases. The identification of effectors is a crucial step in understanding the mechanisms of bacterial pathogenicity, but this remains a major challenge. In this study, we used the full-length embedding features generated by six pre-trained protein language models to train classifiers predicting T4SEs and compared their performance. We integrated three modules into a model called T4SEpp. The first module searched for full-length homologs of known T4SEs, signal sequences, and effector domains; the second module fine-tuned a machine learning model using data for a signal sequence feature; and the third module used the three best-performing pre-trained protein language models. T4SEpp outperformed other state-of-the-art (SOTA) software tools, achieving ∼0.98 accuracy at a high specificity of ∼0.99, based on the assessment of an independent validation dataset. T4SEpp predicted 13 T4SEs from Helicobacter pylori, including the well-known CagA and 12 other potential ones, among which eleven could potentially interact with human proteins. This suggests that these potential T4SEs may be associated with the pathogenicity of H. pylori. Overall, T4SEpp provides a better solution to assist in the identification of bacterial T4SEs and facilitates studies of bacterial pathogenicity. T4SEpp is freely accessible at https://bis.zju.edu.cn/T4SEpp.

Rapid profiling of carcinogenic types of Helicobacter pylori infection via deep learning analysis of label-free SERS spectra of human serum

WHO classified Helicobacter pylori as a Group I carcinogen for gastric cancer as early as 1994. However, despite the high prevalence of H. pylori infection, only about 3 % of infected individuals eventually develop gastric cancer, with the highly virulent H. pylori strains expressing cytotoxin-associated protein (CagA) and vacuolating cytotoxin (VacA) being critical factors in gastric carcinogenesis. It is well known that H. pylori infection is divided into two types in terms of the presence and absence of CagA and VacA toxins in serum, that is, carcinogenic Type I infection (CagA+/VacA+, CagA+/VacA-, CagA-/VacA+) and non-carcinogenic Type II infection (CagA-/VacA-). Currently, detecting the two carcinogenic toxins in active modes is mainly done by diagnosing their serological antibodies. However, the method is restricted by expensive reagents and intricate procedures. Therefore, establishing a rapid, accurate, and cost-effective way for serological profiling of carcinogenic H. pylori infection holds significant implications for effectively guiding H. pylori eradication and gastric cancer prevention. In this study, we developed a novel method by combining surface-enhanced Raman spectroscopy with the deep learning algorithm convolutional neural network to create a model for distinguishing between serum samples with Type I and Type II H. pylori infections. This method holds the potential to facilitate rapid screening of H. pylori infections with high risks of carcinogenesis at the population level, which can have long-term benefits in reducing gastric cancer incidence when used for guiding the eradication of H. pylori infections.

Amino acid deletions at positions 893 and 894 of cytotoxin-associated gene A protein affect Helicobacter pylori gastric epithelial cell interactions

BACKGROUND

Helicobacter pylori (H. pylori) persistently colonizes the human gastric mucosa in more than 50% of the global population, leading to various gastroduodenal diseases ranging from chronic gastritis to gastric carcinoma. Cytotoxin-associated gene A (CagA) protein, an important oncoprotein, has highly polymorphic Glu-Pro-Ile-Tyr-Ala segments at the carboxyl terminus, which play crucial roles in pathogenesis. Our previous study revealed a significant association between amino acid deletions at positions 893 and 894 and gastric cancer.

AIM

To investigate the impact of amino acid deletions at positions 893 and 894 on CagA function.

METHODS

We selected a representative HZT strain from a gastric cancer patient with amino acid deletions at positions 893 and 894. The cagA gene was amplified and mutated into cagA-NT and cagA-NE (sequence characteristics of strains from nongastric cancer patients), cloned and inserted into pAdtrack-CMV, and then transfected into AGS cells. The expression of cagA and its mutants was examined using real-time polymerase chain reaction and Western blotting, cell elongation via cell counting, F-actin cytoskeleton visualization using fluorescence staining, and interleukin-8 (IL-8) secretion via enzyme-linked immunosorbent assay.

RESULTS

The results revealed that pAdtrack/cagA induced a more pronounced hummingbird phenotype than pAdtrack/cagA-NT and pAdtrack/cagA-NE (40.88 ± 3.10 vs 32.50 ± 3.17, P < 0.001 and 40.88 ± 3.10 vs 32.17 ± 3.00, P < 0.001) at 12 hours after transfection. At 24 hours, pAdtrack/cagA-NE induced significantly fewer hummingbird phenotypes than pAdtrack/cagA and pAdtrack/cagA-NT (46.02 ± 2.12 vs 53.90 ± 2.10, P < 0.001 and 46.02 ± 2.12 vs 51.15 ± 3.74, P < 0.001). The total amount of F-actin caused by pAdtrack/cagA was significantly lower than that caused by pAdtrack/cagA-NT and pAdtrack/cagA-NE (27.54 ± 17.37 vs 41.51 ± 11.90, P < 0.001 and 27.54 ± 17.37 vs 41.39 ± 14.22, P < 0.001) at 12 hours after transfection. Additionally, pAdtrack/cagA induced higher IL-8 secretion than pAdtrack/cagA-NT and pAdtrack/cagA-NE at different times after transfection.

CONCLUSION

Amino acid deletions at positions 893 and 894 enhance CagA pathogenicity, which is crucial for revealing the pathogenic mechanism of CagA and identifying biomarkers of highly pathogenic H. pylori.

Gastric cancer-Epidemiology, modifiable and non-modifiable risk factors, challenges and opportunities: An updated review

Gastric cancer represents a significant global health challenge due to its high mortality and incidence rates, particularly in Eastern Asia, Eastern Europe, and South America. This comprehensive review synthesizes the latest epidemiological data and explores both modifiable and non-modifiable risk factors associated with gastric cancer, aiming to delineate the multifactorial etiology of this disease. Modifiable risk factors include Helicobacter pylori infection, obesity, dietary habits, smoking and alcohol consumption, whereas nonmodifiable factors comprise genetic predispositions, age, family history and male gender. The interplay of these factors significantly impacts the risk and progression of gastric cancer, suggesting potential preventive strategies. The challenges in treating gastric cancer are considerable, largely because of the late-stage diagnosis and the heterogeneity of the disease, which complicate effective treatment regimens. Current treatment strategies involve a combination of surgery, chemotherapy, radiotherapy, and targeted therapies. The FLOT regimen (5-FU, Leucovorin, Oxaliplatin and Docetaxel) is now a standard for resectable cases in Europe and the US, showing superior survival and response rates over ECF and ECX regimens. For HER2-positive gastric cancer, trastuzumab combined with chemotherapy improves overall survival, as demonstrated by the ToGA trial. Additionally, immune checkpoint inhibitors like pembrolizumab and nivolumab offer promising results. However, the five-year survival rate remains low, underscoring the urgency for improved therapeutic approaches. Recent advancements in molecular biology and cancer genomics have begun to pave the way for personalized medicine in gastric cancer care, focusing on molecular targeted therapies and immunotherapy. This review also highlights the critical need for better screening methods that could facilitate early detection and treatment, potentially improving the prognosis. By integrating epidemiological insights with new therapeutic strategies, this article aims to thoroughly understand of gastric cancer's dynamics and outline a framework for future research and clinical management, advocating for a multidisciplinary approach to tackle this formidable disease.

GRB7-mediated enhancement of cell malignant characteristics induced by Helicobacter pylori infection

Growth factor receptor bound protein 7 (GRB7) is reportedly upregulated in human gastric cancer (GC), which is closely associated with tumor progression and prognosis. However, the mechanism underlying its dysregulation in GC remains poorly understood. In this study, we found that GRB7 overexpression was associated with Helicobacter pylori (H. pylori) infection. GC cells (AGS and MGC-803) infection assays revealed that this upregulation was mediated by the transcription factor STAT3, and activation of STAT3 by H. pylori promoted GRB7 expression in infected GC cells. Moreover, CagA, the key virulence factor of H. pylori, was found involved in STAT3-mediated GRB7 overexpression. The overexpressed GRB7 further promoted GC cell proliferation, migration, and invasion by activating ERK signaling. Mice infection was further used to investigate the action of GRB7. In H. pylori infection, GRB7 expression in mice gastric mucosa was elevated, and higher STAT3 and ERK activation were also detected. These results revealed GRB7-mediated pathogenesis in H. pylori infection, in which H. pylori activates STAT3, leading to increased GRB7 expression, then promotes activation of the ERK signal, and finally enhances malignant properties of infected cells. Our findings elucidate the role of GRB7 in H. pylori-induced gastric disorders, offering new prospects for the treatment and prevention of H. pylori-associated gastric carcinogenesis by targeting GRB7.

Virulence gene polymorphisms in Shandong Helicobacter pylori strains and their relevance to gastric cancer

BACKGROUND

Helicobacter pylori (H. pylori) virulence factors, particularly the cagA and vacA genotypes, play important roles in the pathogenic process of gastrointestinal disease.

METHODS

The cagA and vacA genotypes of 87 H. pylori strains were determined by PCR and sequencing. The EPIYA and CM motif patterns were analyzed and related to clinical outcomes. We examined the associations between the virulence genes of H. pylori and gastrointestinal diseases in Shandong, and the results were analyzed via the chi-square test and logistic regression model.

RESULTS

Overall, 76 (87.36%) of the strains carried the East Asian-type CagA, with the ABD types being the most prevalent (90.79%). However, no significant differences were observed among the different clinical outcomes. The analysis of CagA sequence types revealed 8 distinct types, encompassing 250 EPIYA motifs, including 4 types of EPIYA or EPIYA-like sequences. Additionally, 28 CM motifs were identified, with the most prevalent patterns being E (66.67%), D (16.09%), and W-W (5.75%). Notably, a significant association was discovered between strains with GC and the CM motif pattern D (P < 0.01). With respect to the vacA genotypes, the strains were identified as s1, s2, m1, m2, i1, i2, d1, d2, c1, and c2 in 87 (100%), 0 (0), 26 (29.89%), 61 (70.11%), 73 (83.91%), 14 (16.09%), 76 (87.36%), 11 (12.64%), 18 (20.69%), and 69 (79.31%), respectively. Specifically, the vacA m1 and c1 genotypes presented a significantly greater prevalence in strains from GC compared to CG (P < 0.05). Following adjustment for age and sex, the vacA c1 genotype demonstrated a notable association with GC (OR = 5.174; 95% CI, 1.402-20.810; P = 0.012). This association was both independent of and more pronounced than the correlations between vacA m1 and GC.

CONCLUSIONS

CagA proteins possessing CM motif pattern D were more frequently observed in patients with GC (P < 0.01), implying a potentially higher virulence of CM motif pattern D than the other CM motif patterns. Moreover, a strong positive association was identified between the vacA c1 genotype and GC, indicating that the vacA c1 genotype is a robust risk indicator for GC among male patients aged ≥55 years in Shandong.

Helicobacter pylori positive oral squamous cell carcinoma demonstrate higher pathological tumor staging and poorer overall survival

BACKGROUND

Helicobacter pylori (H pylori), a bacterium characterized by its spiral shape and gram-negative nature, impacts approximately half of the global population, showing a greater prevalence in developing nations. There are various factors that contribute to the pathogenicity of H pylori in the gastric mucosa, leading to gastric ulcer, gastritis and gastric cancers. The relationship between H pylori and gastric cancers has been well documented. The association between Oral Squamous Cell Carcinoma (OSCC) and H pylori still remains a grey field. The study aimed to evaluate the presence of H pylori in OSCC.

MATERIALS AND METHODS

The study consisted of 46 case samples and 21 controls. The case samples comprised of histopathologically confirmed cases of OSCC obtained from patients undergoing wide local excision. Fresh tissue samples were collected during cryosection and stored in eppendorf tubes. The control samples were collected from the gingiva and buccal mucosa of apparently healthy patients with no history of habits, undergoing procedures such as gingivectomy and impaction. All the cases and controls were subjected to immunohistochemistry for Helicobacter pylori antibody. The cases demonstrating Helicobacter pylori in immunohistochemistry further underwent additional Real-Time- Polymerase Chain Reaction (RT-PCR) and culture methodology for subsequent confirmation.

RESULTS

15/46 cases (32.6 %) showed positive immunohistochemical expression of H pylori in OSCC, while all the twenty-one controls were negative (p value 0.001). Out of the 15 cases tested using culture methodology, a total of 7 cases, representing 46.7 % of the sample, were positive for the presence of H pylori (p- value 0.003). Similar statistically significant results were also obtained for 16S rRNA gene with RT- PCR. Furthermore, H pylori positive cases were frequently found in higher pathological tumor staging. A significant increase in overall survival rate was evident among the H pylori negative cases.

CONCLUSION

Helicobacter pylori was significantly expressed in OSCC tissues when compared to healthy tissues. Immunohistochemical analysis of the presence of H pylori in FFPE OSCC samples yielded more positive results when compared to culture and PCR methodology. We opine that in OSCC, H pylori may have a role in the faster progression of the disease, rather than merely a 'chance spectator'.

Helicobacter pylori triggers inflammation and oncogenic transformation by perturbing the immune microenvironment

The immune microenvironment plays a critical regulatory role in the pathogenesis of Helicobacter pylori (H. pylori). Understanding the mechanisms that drive the transition from chronic inflammation to cancer may provide new insights for early detection of gastric cancer. Although chronic inflammation is frequent in precancerous gastric conditions, the monitoring function of the inflammatory microenvironment in the progression from H. pylori-induced chronic inflammation to gastric cancer remains unclear. This literature review summarizes significant findings on how H. pylori triggers inflammatory responses and facilitates cancer development through the immune microenvironment. Furthermore, the implications for future research and clinical applications are also addressed. The review is divided into four main sections: inflammatory response and immune evasion mechanisms induced by H. pylori, immune dysregulation associated with gastric cancer, therapeutic implications, and future perspectives on H. pylori-induced gastric carcinogenesis with a focus on the immune microenvironment.

Multiple biological characteristics and functions of intestinal biofilm extracellular polymers: friend or foe?

The gut microbiota is vital to human health, and their biofilms significantly impact intestinal immunity and the maintenance of microbial balance. Certain pathogens, however, can employ biofilms to elude identification by the immune system and medical therapy, resulting in intestinal diseases. The biofilm is formed by extracellular polymorphic substances (EPS), which shield microbial pathogens from the host immune system and enhance its antimicrobial resistance. Therefore, investigating the impact of extracellular polysaccharides released by pathogens that form biofilms on virulence and defence mechanisms is crucial. In this review, we provide a comprehensive overview of current pathogenic biofilm research, deal with the role of extracellular polymers in the formation and maintenance of pathogenic biofilm, and elaborate different prevention and treatment strategies to provide an innovative approach to the treatment of intestinal pathogen-based diseases.

Oral microbiota and gastric cancer: recent highlights and knowledge gaps

Gastric cancer is one of the most common malignant tumors worldwide and has a high mortality rate. However, tests for the early screening and diagnosis of gastric cancer are limited and invasive. Certain oral microorganisms are over-expressed in gastric cancer, but there is heterogeneity among different studies. Notably, each oral ecological niche harbors specific microorganisms. Among them, tongue coating, saliva, and dental plaque are important and unique ecological niches in the oral cavity. The colonization environment in different oral niches may be a source of heterogeneity. In this paper, we systematically discuss the latest developments in the field of the oral microbiota and gastric cancer and elucidate the enrichment of microorganisms in the oral ecological niches of the tongue coatings, saliva, and dental plaque in gastric cancer patients. The various potential mechanisms by which the oral microbiota induces gastric cancer (activation of an excessive inflammatory response; promotion of proliferation, migration, invasion, and metastasis; and secretion of carcinogens, leading to imbalance in gastric microbial communities) are explored. In this paper, we also highlight the applications of the rapeutics targeting the oral microbiota in gastric cancer and suggests future research directions related to the relationship between the oral microbiota and gastric cancer.

Analyses of the association between Helicobacter pylori antibody titre and pathogenicity before and after eradication: results of the Kyushu and Okinawa population study, a retrospective observational cohort study

OBJECTIVES

To assess the utility of Helicobacter pylori antibody testing, we evaluated the correlation between the H. pylori antibody titre and H. pylori-associated pathogenicity and the changes in antibody titre after H. pylori eradication therapy.

DESIGN

A retrospective observational cohort study.

SETTING AND PARTICIPANTS

From 2004 to 2016, medical check-ups were performed in different regions of Japan. In total, 324 subjects infected with H. pylori who received H. pylori eradication therapy were enrolled; H. pylori was eradicated in 266 of these subjects. We examined the associations between H. pylori antibody titre with pepsinogen and the presence or absence of H. pylori-associated pathogenic proteins, such as cytotoxin-associated gene A and vacuolating cytotoxin gene A, at baseline and after H. pylori eradication therapy.

RESULTS

The H.pylori antibody titre showed a positive correlation with pepsinogen II and a negative correlation with the pepsinogen I/II ratio. Moreover, the H.pylori antibody titre significantly correlated with the positive rates of H. pylori-associated pathogenic protein before eradication therapy. Antibody titres decreased after eradication, the pepsinogen I/II ratio increased and the H. pylori-associated pathogenic protein-positive rate decreased in patients with successful eradication. The determination of eradication using the decline in antibody titre 6 months after eradication therapy was useful (area under the receiver operating characteristic curve: 0.98).

CONCLUSIONS

Our data indicate that the H. pylori antibody titre may represent the degree of pathogenicity. The H. pylori antibody titre was associated with attenuation of pathogenicity in patients with H. pylori eradication, indicating the clinical utility of H. pylori antibody testing.

Rapid and multi-target genotyping of Helicobacter pylori with digital microfluidics

Helicobacter pylori (H. pylori) infection correlates closely with gastric diseases such as gastritis, ulcers, and cancer, influencing more than half of the world's population. Establishing a rapid, precise, and automated platform for H. pylori diagnosis is an urgent clinical need and would significantly benefit therapeutic intervention. Recombinase polymerase amplification (RPA)-CRISPR recently emerged as a promising molecular diagnostic assay due to its rapid detection capability, high specificity, and mild reaction conditions. In this work, we adapted the RPA-CRISPR assay on a digital microfluidics (DMF) system for automated H. pylori detection and genotyping. The system can achieve multi-target parallel detection of H. pylori nucleotide conservative genes (ureB) and virulence genes (cagA and vacA) across different samples within 30 min, exhibiting a detection limit of 10 copies/rxn and no false positives. We further conducted tests on 80 clinical saliva samples and compared the results with those derived from real-time quantitative polymerase chain reaction, demonstrating 100% diagnostic sensitivity and specificity for the RPA-CRISPR/DMF method. By automating the assay process on a single chip, the DMF system can significantly reduce the usage of reagents and samples, minimize the cross-contamination effect, and shorten the reaction time, with the additional benefit of losing the chance of experiment failure/inconsistency due to manual operations. The DMF system together with the RPA-CRISPR assay can be used for early detection and genotyping of H. pylori with high sensitivity and specificity, and has the potential to become a universal molecular diagnostic platform.

Implications of lncRNAs in Helicobacter pylori-associated gastrointestinal cancers: underlying mechanisms and future perspectives

Helicobacter pylori (H. pylori) is a harmful bacterium that is difficult to conveniently diagnose and effectively eradicate. Chronic H. pylori infection increases the risk of gastrointestinal diseases, even cancers. Despite the known findings, more underlying mechanisms are to be deeply explored to facilitate the development of novel prevention and treatment strategies of H. pylori infection. Long noncoding RNAs (lncRNAs) are RNAs with more than 200 nucleotides. They may be implicated in cell proliferation, inflammation and many other signaling pathways of gastrointestinal cancer progression. The dynamic expression of lncRNAs indicates their potential to be diagnostic or prognostic biomarkers. In this paper, we comprehensively summarize the processes of H. pylori infection and the treatment methods, review the known findings of lncRNA classification and functional mechanisms, elucidate the roles of lncRNAs in H. pylori-related gastrointestinal cancer, and discuss the clinical perspectives of lncRNAs.

Unravelling the role of intratumoral bacteria in digestive system cancers: current insights and future perspectives

Recently, research on the human microbiome, especially concerning the bacteria within the digestive system, has substantially advanced. This exploration has unveiled a complex interplay between microbiota and health, particularly in the context of disease. Evidence suggests that the gut microbiome plays vital roles in digestion, immunity and the synthesis of vitamins and neurotransmitters, highlighting its significance in maintaining overall health. Conversely, disruptions in these microbial communities, termed dysbiosis, have been linked to the pathogenesis of various diseases, including digestive system cancers. These bacteria can influence cancer progression through mechanisms such as DNA damage, modulation of the tumour microenvironment, and effects on the host's immune response. Changes in the composition and function within the tumours can also impact inflammation, immune response and cancer therapy effectiveness. These findings offer promising avenues for the clinical application of intratumoral bacteria for digestive system cancer treatment, including the potential use of microbial markers for early cancer detection, prognostication and the development of microbiome-targeted therapies to enhance treatment outcomes. This review aims to provide a comprehensive overview of the pivotal roles played by gut microbiome bacteria in the development of digestive system cancers. Additionally, we delve into the specific contributions of intratumoral bacteria to digestive system cancer development, elucidating potential mechanisms and clinical implications. Ultimately, this review underscores the intricate interplay between intratumoral bacteria and digestive system cancers, underscoring the pivotal role of microbiome research in transforming diagnostic, prognostic and therapeutic paradigms for digestive system cancers.

Comparison of gastric inflammation and metaplasia induced by Helicobacter pylori or Helicobacter felis colonization in mice

Gastric cancer is the fifth most diagnosed cancer in the world. Infection by the bacteria Helicobacter pylori (HP) is associated with approximately 75% of gastric cancer cases. HP infection induces chronic gastric inflammation, damaging the stomach and fostering carcinogenesis. Most mechanistic studies on gastric cancer initiation are performed in mice and utilize either mouse-adapted strains of HP or the natural mouse pathogen Helicobacter felis (HF). Here, we identified the differences in gastric inflammation, atrophy, and metaplasia associated with HP and HF infection in mice. PMSS1 HP strain or the CS1 HF strain were co-cultured with mouse peritoneal macrophages to assess their immunostimulatory effects. HP and HF induced similar cytokine production from cultured mouse peritoneal macrophages revealing that both bacteria exhibit similar immunostimulatory effects in vitro. Next, C57BL/6J mice were infected with HP or HF and were assessed 2 months post-infection. HP-infected mice caused modest inflammation within both the gastric corpus and antrum, and did not induce significant atrophy within the gastric corpus. In contrast, HF induced significant inflammation throughout the gastric corpus and antrum. Moreover, HF infection was associated with significant atrophy of the chief and parietal cell compartments and induced the expression of pyloric metaplasia (PM) markers. HP is poorly immunogenic compared to HF. HF induces dramatic CD4+ T cell activation, which is associated with increased gastric cancer risk in humans. Thus, HP studies in mice are better suited for studies on colonization, while HF is more strongly suited for studies on the effects of gastric inflammation on tumorigenesis.  .

IMPORTANCE

Mouse infection models with Helicobacter species are widely used to study Helicobacter pathogenesis and gastric cancer initiation. However, Helicobacter pylori is not a natural mouse pathogen, and mouse-adapted H. pylori strains are poorly immunogenic. In contrast, Helicobacter felis is a natural mouse pathogen that induces robust gastric inflammation and is often used in mice to investigate gastric cancer initiation. Although both bacterial strains are widely used, their disease pathogenesis in mice differs dramatically. However, few studies have directly compared the pathogenesis of these bacterial species in mice, and the contrasting features of these two models are not clearly defined. This study directly compares the gastric inflammation, atrophy, and metaplasia development triggered by the widely used PMSS1 H. pylori and CS1 H. felis strains in mice. It serves as a useful resource for researchers to select the experimental model best suited for their studies.

Helicobacter pylori cagA, vacA, and iceA genotypes and clinical outcomes: a cross-sectional study in central Vietnam

Helicobacter pylori is the most common cause of gastroduodenal diseases. The concept that cagA-positive H. pylori is a risk factor for gastric cancer appears to be true only for H. pylori strains from Western countries. Other virulent genes may have a synergistic interaction with cagA during pathogenesis. This study aims to investigate H. pylori cagA, vacA, and iceA prevalence, genotypes, and their association to clinical outcomes in Vietnamese patients. The cagA status and vacA and iceA genotypes were determined using the PCR technique on DNA extracted from gastric biopsies of 141 patients with gastroduodenal diseases. After performing molecular analysis for cagA, vacA, and iceA genes, samples with mixed H. pylori strains, positivity, or negativity for both cagA and cagPAI-empty site, or unidentified genotypes were excluded. Finally, 107 samples were examined. The presence of the cagA, vacA, and iceA genes were detected in 77.6%, 100%, and 80.4% of cases, respectively. Notably, cagA( +) with EPIYA-ABD, vacA s1i1m1, vacA s1i1m2, iceA1, and iceA2 accounted for 73.8%, 44.9%, 33.6%, 48.6%, and 31.8% of cases, respectively. Four iceA2 subtypes (24-aa, 59-aa, 94-aa, and 129-aa variants) were found, with the 59-aa variant the most prevalent (70.6%). The cagA( +)/vacAs1i1m1/iceA1 and cagA( +)/vacAs1i1m2/iceA1 combinations were found in 26.2% and 25.1% of cases, respectively. A multivariable logistic regression analysis was performed, after adjusting for age and gender, with the gastritis group was used as a reference control. Statistically significant associations were found between the vacA s1i1m2 genotype, the iceA1 variant, and the cagA( +)/vacAs1i1m2/iceA1 combination and gastric cancer; the adjusted ORs were estimated as 18.02 (95% CI: 3.39-95.81), 4.09 (95% CI: 1.1-15.08), and 16.19 (95% CI: 3.42-76.66), respectively. Interestingly, for the first time, our study found that vacA s1i1m2, but not vacA s1i1m1, was a risk factor for gastric cancer. This study illustrates the genetic diversity of the H. pylori cagA, vacA, and iceA genes across geographical regions and contributes to understanding the importance of these genotypes for clinical outcomes.

Cortactin-dependent control of Par1b-regulated epithelial cell polarity in Helicobacter infection

Cell polarity is crucial for gastric mucosal barrier integrity and mainly regulated by polarity-regulating kinase partitioning-defective 1b (Par1b). During infection, the carcinogen Helicobacter pylori hijacks Par1b via the bacterial oncoprotein CagA leading to loss of cell polarity, but the precise molecular mechanism is not fully clear. Here we discovered a novel function of the actin-binding protein cortactin in regulating Par1b, which forms a complex with cortactin and the tight junction protein zona occludens-1 (ZO-1). We found that serine phosphorylation at S405/418 and the SH3 domain of cortactin are important for its interaction with both Par1b and ZO-1. Cortactin knockout cells displayed disturbed Par1b cellular localization and exhibited morphological abnormalities that largely compromised transepithelial electrical resistance, epithelial cell polarity, and apical microvilli. H. pylori infection promoted cortactin/Par1b/ZO-1 abnormal interactions in the tight junctions in a CagA-dependent manner. Infection of human gastric organoid-derived mucosoids supported these observations. We therefore hypothesize that CagA disrupts gastric epithelial cell polarity by hijacking cortactin, and thus Par1b and ZO-1, suggesting a new signaling pathway for the development of gastric cancer by Helicobacter.

Complex Roles of PTPN11/SHP2 in Carcinogenesis and Prospect of Targeting SHP2 in Cancer Therapy

The non-receptor tyrosine phosphatase SHP2 has been at the center of cell signaling research for three decades. SHP2 is required to fully activate the RTK-RAS-ERK cascade, although the underlying mechanisms are not completely understood. PTPN11, coding for SHP2, is the first identified proto-oncogene that encodes a tyrosine phosphatase, with dominantly activating mutations detected in leukemias and solid tumors. However, SHP2 has been shown to have pro- and anti-oncogenic effects, and the most recent data reveal opposite activities of SHP2 in tumor cells and microenvironment cells. Allosteric SHP2 inhibitors show promising anti-tumor effects and overcome resistance to inhibitors of RAS-ERK signaling in animal models. Many clinical trials with orally bioactive SHP2 inhibitors, alone or combined with other regimens, are ongoing for a variety of cancers worldwide, with therapeutic outcomes yet unknown. This review discusses the multi-faceted SHP2 functions in oncogenesis, preclinical studies and clinical trials with SHP2 inhibitors in oncological treatment.

In silico prospective analysis of the medicinal plants activity on the CagA oncoprotein from Helicobacter pylori

BACKGROUND

Colonization with Helicobacter pylori (H. pylori) has a strong correlation with gastric cancer, and the virulence factor CagA is implicated in carcinogenesis. Studies have been conducted using medicinal plants with the aim of eliminating the pathogen; however, the possibility of blocking H. pylori-induced cell differentiation to prevent the onset and/or progression of tumors has not been addressed. This type of study is expensive and time-consuming, requiring in vitro and/or in vivo tests, which can be solved using bioinformatics. Therefore, prospective computational analyses were conducted to assess the feasibility of interaction between phenolic compounds from medicinal plants and the CagA oncoprotein.

AIM

To perform a computational prospecting of the interactions between phenolic compounds from medicinal plants and the CagA oncoprotein of H. pylori.

METHODS

In this in silico study, the structures of the phenolic compounds (ligands) kaempferol, myricetin, quercetin, ponciretin (flavonoids), and chlorogenic acid (phenolic acid) were selected from the PubChem database. These phenolic compounds were chosen based on previous studies that suggested medicinal plants as non-drug treatments to eliminate H. pylori infection. The three-dimensional structure model of the CagA oncoprotein of H. pylori (receptor) was obtained through molecular modeling using computational tools from the I-Tasser platform, employing the threading methodology. The primary sequence of CagA was sourced from GenBank (BAK52797.1). A screening was conducted to identify binding sites in the structure of the CagA oncoprotein that could potentially interact with the ligands, utilizing the GRaSP online platform. Both the ligands and receptor were prepared for molecular docking using AutoDock Tools 4 (ADT) software, and the simulations were carried out using a combination of ADT and AutoDock Vina v.1.2.0 software. Two sets of simulations were performed: One involving the central region of CagA with phenolic compounds, and another involving the carboxy-terminus region of CagA with phenolic compounds. The receptor-ligand complexes were then analyzed using PyMol and BIOVIA Discovery Studio software.

RESULTS

The structure model obtained for the CagA oncoprotein exhibited high quality (C-score = 0.09) and was validated using parameters from the MolProbity platform. The GRaSP online platform identified 24 residues (phenylalanine and leucine) as potential binding sites on the CagA oncoprotein. Molecular docking simulations were conducted with the three-dimensional model of the CagA oncoprotein. No complexes were observed in the simulations between the carboxy-terminus region of CagA and the phenolic compounds; however, all phenolic compounds interacted with the central region of the oncoprotein. Phenolic compounds and CagA exhibited significant affinity energy (-7.9 to -9.1 kcal/mol): CagA/kaempferol formed 28 chemical bonds, CagA/myricetin formed 18 chemical bonds, CagA/quercetin formed 16 chemical bonds, CagA/ponciretin formed 13 chemical bonds, and CagA/chlorogenic acid formed 17 chemical bonds. Although none of the phenolic compounds directly bound to the amino acid residues of the K-Xn-R-X-R membrane binding motif, all of them bound to residues, mostly positively or negatively charged, located near this region.

CONCLUSION

In silico, the tested phenolic compounds formed stable complexes with CagA. Therefore, they could be tested in vitro and/or in vivo to validate the findings, and to assess interference in CagA/cellular target interactions and in the oncogenic differentiation of gastric cells.

Resident Microbiome of Kidney Tumors

Emerging research has uncovered the significance of microbiota in carcinogenesis, with specific bacterial infectious agents linked to around 15% of malignant tumors. This review is focused on the resident kidney microbiome, its composition, and alterations in various diseases. Recent studies have shown that bacteria can infiltrate the kidney, with differences between normal and tumor tissue. These studies have identified distinctive microorganisms unique to both conditions, hinting at their potential clinical relevance. Research into the kidney microbiome diversity reveals differences in tumor tissue, with specific taxa associated with different histological types. Notably, the alpha diversity indices suggest variations in bacterial content between tumor and normal tissue, offering insights into potential diagnostic and prognostic use of these markers. Better studied is the impact of the gut microbiome on therapy efficacy in malignant kidney tumors. Antibiotics, which can alter the gut microbiome, have been linked to survival outcomes in patients receiving targeted therapy and immunotherapy. The findings suggest that the uncontrolled use of antibiotics may not only contribute to bacterial resistance but also disrupt the normal microbiome, potentially influencing the development of oncological diseases. In-depth investigation into the resident kidney microbiome is essential for addressing fundamental and practical aspects of kidney tumor development.

Unveiling the gastric microbiota: implications for gastric carcinogenesis, immune responses, and clinical prospects

High-throughput sequencing has ushered in a paradigm shift in gastric microbiota, breaking the stereotype that the stomach is hostile to microorganisms beyond H. pylori. Recent attention directed toward the composition and functionality of this 'community' has shed light on its potential relevance in cancer. The microbial composition in the stomach of health displays host specificity which changes throughout a person's lifespan and is subject to both external and internal factors. Distinctive alterations in gastric microbiome signature are discernible at different stages of gastric precancerous lesions and malignancy. The robust microbes that dominate in gastric malignant tissue are intricately implicated in gastric cancer susceptibility, carcinogenesis, and the modulation of immunosurveillance and immune escape. These revelations offer fresh avenues for utilizing gastric microbiota as predictive biomarkers in clinical settings. Furthermore, inter-individual microbiota variations partially account for differential responses to cancer immunotherapy. In this review, we summarize current literature on the influence of the gastric microbiota on gastric carcinogenesis, anti-tumor immunity and immunotherapy, providing insights into potential clinical applications.

Dual RNA sequencing of Helicobacter pylori and host cell transcriptomes reveals ontologically distinct host-pathogen interaction

Helicobacter pylori is a highly successful pathogen that poses a substantial threat to human health. However, the dynamic interaction between H. pylori and the human gastric epithelium has not been fully investigated. In this study, using dual RNA sequencing technology, we characterized a cytotoxin-associated gene A (cagA)-modulated bacterial adaption strategy by enhancing the expression of ATP-binding cassette transporter-related genes, metQ and HP_0888, upon coculturing with human gastric epithelial cells. We observed a general repression of electron transport-associated genes by cagA, leading to the activation of oxidative phosphorylation. Temporal profiling of host mRNA signatures revealed the downregulation of multiple splicing regulators due to bacterial infection, resulting in aberrant pre-mRNA splicing of functional genes involved in the cell cycle process in response to H. pylori infection. Moreover, we demonstrated a protective effect of gastric H. pylori colonization against chronic dextran sulfate sodium (DSS)-induced colitis. Mechanistically, we identified a cluster of propionic and butyric acid-producing bacteria, Muribaculaceae, selectively enriched in the colons of H. pylori-pre-colonized mice, which may contribute to the restoration of intestinal barrier function damaged by DSS treatment. Collectively, this study presents the first dual-transcriptome analysis of H. pylori during its dynamic interaction with gastric epithelial cells and provides new insights into strategies through which H. pylori promotes infection and pathogenesis in the human gastric epithelium.

IMPORTANCE

Simultaneous profiling of the dynamic interaction between Helicobacter pylori and the human gastric epithelium represents a novel strategy for identifying regulatory responses that drive pathogenesis. This study presents the first dual-transcriptome analysis of H. pylori when cocultured with gastric epithelial cells, revealing a bacterial adaptation strategy and a general repression of electron transportation-associated genes, both of which were modulated by cytotoxin-associated gene A (cagA). Temporal profiling of host mRNA signatures dissected the aberrant pre-mRNA splicing of functional genes involved in the cell cycle process in response to H. pylori infection. We demonstrated a protective effect of gastric H. pylori colonization against chronic DSS-induced colitis through both in vitro and in vivo experiments. These findings significantly enhance our understanding of how H. pylori promotes infection and pathogenesis in the human gastric epithelium and provide evidence to identify targets for antimicrobial therapies.

Infiltration to infection: key virulence players of Helicobacter pylori pathogenicity

PURPOSE

This study aims to comprehensively review the multifaceted factors underlying the successful colonization and infection process of Helicobacter pylori (H. pylori), a prominent Gram-negative pathogen in humans. The focus is on elucidating the functions, mechanisms, genetic regulation, and potential cross-interactions of these elements.

METHODS

Employing a literature review approach, this study examines the intricate interactions between H. pylori and its host. It delves into virulence factors like VacA, CagA, DupA, Urease, along with phase variable genes, such as babA, babC, hopZ, etc., giving insights about the bacterial perspective of the infection The association of these factors with the infection has also been added in the form of statistical data via Funnel and Forest plots, citing the potential of the virulence and also adding an aspect of geographical biasness to the virulence factors. The biochemical characteristics and clinical relevance of these factors and their effects on host cells are individually examined, both comprehensively and statistically.

RESULTS

H. pylori is a Gram-negative, spiral bacterium that successfully colonises the stomach of more than half of the world's population, causing peptic ulcers, gastric cancer, MALT lymphoma, and other gastro-duodenal disorders. The clinical outcomes of H. pylori infection are influenced by a complex interplay between virulence factors and phase variable genes produced by the infecting strain and the host genetic background. A meta-analysis of the prevalence of all the major virulence factors has also been appended.

CONCLUSION

This study illuminates the diverse elements contributing to H. pylori's colonization and infection. The interplay between virulence factors, phase variable genes, and host genetics determines the outcome of the infection. Despite biochemical insights into many factors, their comprehensive regulation remains an understudied area. By offering a panoramic view of these factors and their functions, this study enhances understanding of the bacterium's perspective, i.e. H. pylori's journey from infiltration to successful establishment within the host's stomach.

Inhibition of the type IV secretion system from antibiotic-resistant Helicobacter pylori clinical isolates supports the potential of Cagα as an anti-virulence target

Helicobacter pylori resistance to antibiotics is a growing problem and it increasingly leads to treatment failure. While the bacterium is present worldwide, the severity of clinical outcomes is highly dependent on the geographical origin and genetic characteristics of the strains. One of the major virulence factors identified in H. pylori is the cag pathogenicity island (cagPAI), which encodes a type IV secretion system (T4SS) used to translocate effectors into human cells. Here, we investigated the genetic variability of the cagPAI among 13 antibiotic-resistant H. pylori strains that were isolated from patient biopsies in Québec. Seven of the clinical strains carried the cagPAI, but only four could be readily cultivated under laboratory conditions. We observed variability of the sequences of CagA and CagL proteins that are encoded by the cagPAI. All clinical isolates induce interleukin-8 secretion and morphological changes upon co-incubation with gastric cancer cells and two of them produce extracellular T4SS pili. Finally, we demonstrate that molecule 1G2, a small molecule inhibitor of the Cagα protein from the model strain H. pylori 26695, reduces interleukin-8 secretion in one of the clinical isolates. Co-incubation with 1G2 also inhibits the assembly of T4SS pili, suggesting a mechanism for its action on T4SS function.

An intranasal influenza virus vector vaccine protects against Helicobacter pylori in mice

Helicobacter pylori is a human pathogen that infects almost half of the population. Antibiotic resistance in H. pylori threatens health and increases the demand for prophylactic and therapeutic vaccines. Traditional oral vaccine research faces considerable challenges because of the epithelial barrier, potential enterotoxicity of adjuvants, and the challenging conditions of the gastric environment. We developed an intranasal influenza A virus (IAV) vector vaccine based on two live attenuated influenza viruses with modified acidic polymerase protein (PA) genes encoding the A subunit of H. pylori neutrophil-activating protein (NapA), named IAV-NapA, including influenza virus A/WSN/33 (WSN)-NapA and A/Puerto Rico/8/34 (PR8)-NapA. These recombinant influenza viruses were highly attenuated and exhibited strong immunogenicity in mice. Vaccination with IAV-NapA induced antigen-specific humoral and mucosal immune responses while stimulating robust Th1 and Th17 cell immune responses in mice. Our findings suggest that prophylactic and therapeutic vaccination with influenza virus vector vaccines significantly reduces colonization of H. pylori and inflammation in the stomach of mice.IMPORTANCEHelicobacter pylori is the most common cause of chronic gastritis and leads to severe gastroduodenal pathology in some patients. Many studies have shown that Th1 and Th17 cellular and gastric mucosal immune responses are critical in reducing H. pylori load. IAV vector vaccines can stimulate these immune responses while overcoming potential adjuvant toxicity and antigen dosing issues. To date, no studies have demonstrated the role of live attenuated IAV vector vaccines in preventing and treating H. pylori infection. Our work indicates that vaccination with IAV-NapA induces antigen-specific humoral, cellular, and mucosal immunity, producing a protective and therapeutic effect against H. pylori infection in BALB/c mice. This undescribed H. pylori vaccination approach may provide valuable information for developing vaccines against H. pylori infection.

Helicobacter pylori with trx1 high expression promotes gastric diseases via upregulating the IL23A/NF-κB/IL8 pathway

BACKGROUND

Helicobacter pylori infection is one of the main causes of gastric cancer. thioredoxin-1 (Trx1) and arginase (RocF) expressed by H. pylori were found to be closely related to its pathogenicity. However, whether Trx1 and RocF can be used in clinical screening of highly pathogenic H. pylori and the pathogenesis of trx1 high expressing H. pylori remain still unknown.

MATERIALS AND METHODS

We investigated the expression level of H. pylori trx1 and H. pylori rocF in human gastric antrum tissues using reverse transcription and quantitative real-time PCR (RT-qPCR) and clarified the clinical application value of trx1 and rocF for screening highly pathogenic H. pylori. The pathogenic mechanism of Trx1 were further explored by RNA-seq of GES-1 cells co-cultured with trx1 high or low expressing H. pylori. Differentially expressed genes and signaling pathways were validated by RT-qPCR, Enzyme-linked immunosorbent assay (ELISA), western blot, immunohistochemistry and immunofluorescence. We also assessed the adherence of trx1 high and low expressing H. pylori to GES-1 cells.

RESULTS

We found that H. pylori trx1 and H. pylori rocF were more significantly expressed in the gastric cancer and peptic ulcer group than that in the gastritis group and the parallel diagnosis of H. pylori trx1 and H. pylori rocF had high sensitivity. The trx1 high expressing H. pylori had stronger adhesion ability to GES-1 cells and upregulated the interleukin (IL) 23A/nuclear factor κappaB (NF-κB)/IL17A, IL6, IL8 pathway.

CONCLUSIONS

H. pylori trx1 and H. pylori rocF can be used in clinical screening of highly pathogenic H. pylori and predicting the outcome of H. pylori infection. The trx1 high expressing H. pylori has stronger adhesion capacity and promotes the development of gastric diseases by upregulating the activation of NF-κB signaling pathway.

Antagonizing roles of SHP1 in the pathogenesis of Helicobacter pylori infection

BACKGROUND

SHP1 has been documented as a tumor suppressor and it was thought to play an antagonistic role in the pathogenesis of Helicobacter pylori infection. In this study, the exact mechanism of this antagonistic action was studied.

MATERIALS AND METHODS

AGS, MGC803, and GES-1 cells were infected with H. pylori, intracellular distribution changes of SHP1 were first detected by immunofluorescence. SHP1 overexpression and knockdown were then constructed in these cells to investigate its antagonistic roles in H. pylori infection. Migration and invasion of infected cells were detected by transwell assay, secretion of IL-8 was examined via ELISA, the cells with hummingbird-like alteration were determined by microexamination, and activation of JAK2/STAT3, PI3K/Akt, and ERK pathways were detected by immunoblotting. Mice infection model was established and gastric pathological changes were evaluated. Finally, the SHP1 activator sorafenib was used to analyze the attenuating effect of SHP1 activation on H. pylori pathogenesis in vitro and in vivo.

RESULTS

The sub-localization of SHP1 changed after H. pylori infection, specifically that the majority of the cytoplasmic SHP1 was transferred to the cell membrane. SHP1 inhibited H. pylori-induced activation of JAK2/STAT3 pathway, PI3K/Akt pathway, nuclear translocation of NF-κB, and then reduced EMT, migration, invasion, and IL-8 secretion. In addition, SHP1 inhibited the formation of CagA-SHP2 complex by dephosphorylating phosphorylated CagA, reduced ERK phosphorylation and the formation of CagA-dependent hummingbird-like cells. In the mice infection model, gastric pathological changes were observed and increased IL-8 secretion, indicators of cell proliferation and EMT progression were also detected. By activating SHP1 with sorafenib, a significant curative effect against H. pylori infection was obtained in vitro and in vivo.

CONCLUSIONS

SHP1 plays an antagonistic role in H. pylori pathogenesis by inhibiting JAK2/STAT3 and PI3K/Akt pathways, NF-κB nuclear translocation, and CagA phosphorylation, thereby reducing cell EMT, migration, invasion, IL-8 secretion, and hummingbird-like changes.

Keystone pathobionts associated with colorectal cancer promote oncogenic reprograming

Fusobacterium nucleatum (Fn) and enterotoxigenic Bacteroides fragilis (ETBF) are two pathobionts consistently enriched in the gut microbiomes of patients with colorectal cancer (CRC) compared to healthy counterparts and frequently observed for their direct association within tumors. Although several molecular mechanisms have been identified that directly link these organisms to features of CRC in specific cell types, their specific effects on the epithelium and local immune compartment are not well-understood. To fill this gap, we leveraged single-cell RNA sequencing (scRNA-seq) on wildtype mice and mouse model of CRC. We find that Fn and ETBF exacerbate cancer-like transcriptional phenotypes in transit-amplifying and mature enterocytes in a mouse model of CRC. We also observed increased T cells in the pathobiont-exposed mice, but these pathobiont-specific differences observed in wildtype mice were abrogated in the mouse model of CRC. Although there are similarities in the responses provoked by each organism, we find pathobiont-specific effects in Myc-signaling and fatty acid metabolism. These findings support a role for Fn and ETBF in potentiating tumorigenesis via the induction of a cancer stem cell-like transit-amplifying and enterocyte population and the disruption of CTL cytotoxic function.

ROS-mediated up-regulation of SAE1 by Helicobacter pylori promotes human gastric tumor genesis and progression

Helicobacter pylori (H. pylori) is a major risk factor of gastric cancer (GC). The SUMO-activating enzyme SAE1(SUMO-activating enzyme subunit 1), which is indispensable for protein SUMOylation, involves in human tumorigenesis. In this study, we used the TIMER and TCGA database to explore the SAE1 expression in GC and normal tissues and Kaplan-Meier Plotter platform for survival analysis of GC patients. GC tissue microarray and gastric samples from patients who underwent endoscopic treatment were employed to detect the SAE1expression. Our results showed that SAE1 was overexpressed in GC tissues and higher SAE1 expression was associated with worse clinical characteristics of GC patients. Cell and animal models showed that H. pylori infection upregulated SAE1, SUMO1, and SUMO2/3 protein expression. Functional assays suggested that suppression of SAE1 attenuated epithelial-mesenchymal transition (EMT) biomarkers and cell proliferation abilities induced by H. pylori. Cell and animal models of ROS inhibition in H. pylori showed that ROS could mediate the H. pylori-induced upregulation of SAE1, SUMO1, and SUMO2/3 protein. RNA sequencing was performed and suggested that knockdown of SAE1 could exert an impact on IGF-1 expression. General, increased SUMOylation modification is involved in H. pylori-induced GC.

Helicobacter pylori CagA-mediated ether lipid biosynthesis promotes ferroptosis susceptibility in gastric cancer

Helicobacter pylori, particularly cytotoxin-associated gene A (CagA)-positive strains, plays a key role in the progression of gastric cancer (GC). Ferroptosis, associated with lethal lipid peroxidation, has emerged to play an important role in malignant and infectious diseases, but the role of CagA in ferroptosis in cancer cells has not been determined. Here, we report that CagA confers GC cells sensitivity to ferroptosis both in vitro and in vivo. Mechanistically, CagA promotes the synthesis of polyunsaturated ether phospholipids (PUFA-ePLs), which is mediated by increased expression of alkylglycerone phosphate synthase (AGPS) and 1-acylglycerol-3-phosphate O-acyltransferase 3 (AGPAT3), leading to susceptibility to ferroptosis. This susceptibility is mediated by activation of the MEK/ERK/SRF pathway. SRF is a crucial transcription factor that increases AGPS transcription by binding to the AGPS promoter region. Moreover, the results demonstrated that CagA-positive cells are more sensitive to apatinib than are CagA-negative cells, suggesting that detecting the H. pylori CagA status may aid patient stratification for treatment with apatinib.

Historical and Molecular Perspectives on the Presence of Helicobacter pylori in Latin America: A Niche to Improve Gastric Cancer Risk Assessment

Helicobacter pylori (H. pylori) is responsible for causing chronic gastritis, which can cause peptic ulcer and premalignant lesions such as atrophic gastritis, intestinal metaplasia, and dysplasia, with the risk of developing gastric cancer. Recent data describe that H. pylori colonizes the gastric mucosa of more than 50% of the world's population; however, this bacterium has been described as infecting the human population since its prehistory. This review focuses on the populations and subpopulations of H. pylori, differentiated by the polymorphisms present in their constitutive and virulence genes. These genes have spread and associated with different human populations, showing variability depending on their geographical distribution, and have evolved together with the human being. The predominant genotypes worldwide, Latin America and Chile, are described to understand the genetic diversity and pathogenicity of H. pylori in different populations and geographic regions. The high similarity in the sequence of virulence genes between H. pylori strains present in Peruvian and Spanish natives in Latin America suggests a European influence. The presence of cagA-positive strains and vacA s1 m1 allelic variants is observed with greater prevalence in Chilean patients with more severe gastrointestinal diseases and is associated with its geographical distribution. These findings highlight the importance of understanding the genetic diversity of H. pylori in different regions of the world for a more accurate assessment of the risk of associated diseases and their potential impact on health.

Cross-talk between Helicobacter pylori and gastric cancer: a scientometric analysis

Background

Helicobacter pylori (HP) is considered a leading risk factor for gastric cancer (GC). The aim of this article is to conduct bibliometric and visual analysis to assess scientific output, identify highly cited papers, summarize current knowledge, and explore recent hotspots and trends in HP/GC research.

Methods

A bibliographic search was conducted on October 24, 2023, to retrieve relevant studies on HP/GC research between 2003 and 2022. The search terms were attached to HP and GC. The main data were from the Web of Science Core Collection (WoSCC). Data visualization was performed using Biblioshiny, VOSviewer, and Microsoft Excel.

Results

In HP/GC research, 1970 papers were retrieved. The total number of papers (Np) in HP/GC was growing from 2003 to 2022. China and Japan were in the leading position and made the most contributions to HP/GC. Vanderbilt University and the US Department of Veterans Affairs had the highest Np. The most productive authors were Peek Jr Richard M. and Piazuelo M Blanca. Helicobacter received the most Np, while Gastroenterology had the most total citations (TC). High-cited publications and keyword clustering were used to identify the current status and trends in HP/GC research, while historical citation analysis provided insight into the evolution of HP/GC research. The hot topics included the effect of HP on gastric tumorigenesis and progression, the pathogenesis of HP-induced GC (HP factors), and the mechanisms by which HP affects GC (host factors). Research in the coming years could focus on topics such as autophagy, gut microbiota, immunotherapy, exosomes, epithelial-mesenchymal transition (EMT), and gamma-glutamyl transpeptidase (GGT).

Conclusion

This study evaluated the global scientific output in HP/GC research and its quantitative characteristics, identified the essential works, and collected information on the current status, main focuses and emerging trends in HP/GC research to provide academics with guidance for future paths.

Remodeling of the gastric environment in Helicobacter pylori-induced atrophic gastritis

Helicobacter pylori colonization of the human stomach is a strong risk factor for gastric cancer. To investigate H. pylori-induced gastric molecular alterations, we used a Mongolian gerbil model of gastric carcinogenesis. Histologic evaluation revealed varying levels of atrophic gastritis (a premalignant condition characterized by parietal and chief cell loss) in H. pylori-infected animals, and transcriptional profiling revealed a loss of markers for these cell types. We then assessed the spatial distribution and relative abundance of proteins in the gastric tissues using imaging mass spectrometry and liquid chromatography with tandem mass spectrometry. We detected striking differences in the protein content of corpus and antrum tissues. Four hundred ninety-two proteins were preferentially localized to the corpus in uninfected animals. The abundance of 91 of these proteins was reduced in H. pylori-infected corpus tissues exhibiting atrophic gastritis compared with infected corpus tissues exhibiting non-atrophic gastritis or uninfected corpus tissues; these included numerous proteins with metabolic functions. Fifty proteins localized to the corpus in uninfected animals were diffusely delocalized throughout the stomach in infected tissues with atrophic gastritis; these included numerous proteins with roles in protein processing. The corresponding alterations were not detected in animals infected with a H. pylori ∆cagT mutant (lacking Cag type IV secretion system activity). These results indicate that H. pylori can cause loss of proteins normally localized to the gastric corpus as well as diffuse delocalization of corpus-specific proteins, resulting in marked changes in the normal gastric molecular partitioning into distinct corpus and antrum regions.IMPORTANCEA normal stomach is organized into distinct regions known as the corpus and antrum, which have different functions, cell types, and gland architectures. Previous studies have primarily used histologic methods to differentiate these regions and detect H. pylori-induced alterations leading to stomach cancer. In this study, we investigated H. pylori-induced gastric molecular alterations in a Mongolian gerbil model of carcinogenesis. We report the detection of numerous proteins that are preferentially localized to the gastric corpus but not the antrum in a normal stomach. We show that stomachs with H. pylori-induced atrophic gastritis (a precancerous condition characterized by the loss of specialized cell types) exhibit marked changes in the abundance and localization of proteins normally localized to the gastric corpus. These results provide new insights into H. pylori-induced gastric molecular alterations that are associated with the development of stomach cancer.