Proton pump inhibitor: The dual role in gastric cancer

Exploring potential biomarkers and lead molecules in gastric cancer by network biology, drug repurposing and virtual screening strategies

Gastric cancer poses a significant global health challenge, necessitating innovative approaches for biomarker discovery and therapeutic intervention. This study employs a multifaceted strategy integrating network biology, drug repurposing, and virtual screening to elucidate and expand the molecular landscape of gastric cancer. We identified and prioritized key genes implicated in gastric cancer by utilizing data from diverse databases and text-mining techniques. Network analysis underscored intricate gene interactions, emphasizing potential therapeutic targets such as CTNNB1, BCL2, TP53, etc, and highlighted ACTB among the top hub genes crucial in disease progression. Drug repurposing on 626 FDA-approved drugs for digestive system-related cancers revealed Norgestimate and Nimesulide as likely top candidates for gastric cancer, validated by molecular docking and dynamics simulations. Further, combinatorial synthesis of scaffold libraries derived from known chemotypes generated 56,160 virtual compounds, of which 76 new compounds were prioritized based on promising binding affinities and interactions at critical residues. Hotspot residue analysis identified GLU 214 and others as essential for ligand binding stability, enhancing compound efficacy and specificity. These findings support the therapeutic potential of targeting beta-actin protein in gastric cancer treatment, suggesting a future for further experimental validation and clinical translation. In conclusion, this study highlights the potential of repurposable drugs and virtual screening which can be used in combination with existing anti-gastric cancer drugs for gastric cancer therapy, emphasizing the role of computational methodologies in drug discovery.

Echinophora tournefortii Jaub. & Spach: Evaluation of the effect on indomethacin-induced gastric ulser in rats and phytochemical analyses by LC-HRMS

E. tournefortii has wound healing properties in folk medicine and 5% infusions are used for stomach ulcers. It is also used in colds, abdominal pain, digestive problems, as an appetite enhancer and antispasmodic. For this purpose, in the study biochemical and histopathological evaluation of the ulcer protective effect of the extract obtained from the E. tournefortii in the indomethacin-induced gastric ulcer model in rats was aimed to develop new strategies in the treatment of ulcers. The phytochemical profile of the plant was elucidated for the first time by LC-HRMS in this study. The results indicate that, in terms of TNF-α, IL-1β, IL-8, IL-6, PGE2, NF-κB, VEGF, NO, COX-1 and COX-2 biochemical parameters, E. tournefortii protects the gastric mucosa to the inflammation, and also modulates the PGE2 pathway, and has a similar effect or even a more positive effect than the reference substance lansoprazole. According to LC-HRMS analysis results, chlorogenic acid, genistein and quinic acid were the main constituents of E. tournefortii extract with 1397.081, 1014.177 and 992.527μg/g extract, respectively. Considering the anti-inflammatory and antioxidant effects of these phenolic components, it is thought that the major components are responsible for the anti-ulcer activity of the E. tournefortii extract.

Proton pump inhibitor use is associated with increased liver steatosis

Despite proton pump inhibitors (PPIs) being generally safe, there are questions about their potential long-term complications. The present study aimed to investigate the association between PPI therapy and the incidence of hepatic steatosis and liver fibrosis in the outpatient population of the United States. The present study included 7,395 individuals aged ≥20 years who underwent hepatic vibration-controlled transient elastography (VCTE) examination. The data were obtained from the January 2017 to March 2020 pre-pandemic National Health and Nutrition Examination Survey. Among the 7,395 adults who were included (mean age, 50.59 years; 3,656 male), 9.8% were prescribed PPIs. Following multivariable adjustment, the use of PPIs was significantly associated with hepatic steatosis [odds ratio (OR), 1.25; 95% confidence interval (CI), 1.02-1.53]. Prolonged use of PPIs was found to increase the risk of developing hepatic steatosis over time (P=0.006). Sensitivity analyses using different definitions of hepatic steatosis, such as a controlled attenuation parameter ≥285 dB/m (OR, 1.19; CI, 1.01-1.40), non-alcoholic fatty liver disease (OR, 1.50; 95% CI, 1.16-1.93) and metabolic dysfunction-associated steatotic liver disease (OR, 1.26; 95% CI, 1.05-1.52), consistently demonstrated an association between PPI prescription and hepatic steatosis. The administration of PPI therapy was linked with hepatic steatosis in US adults, although no significant association was observed with liver stiffness, as determined by VCTE.

Proton pump inhibitors stabilize the expression of PD-L1 on cell membrane depending on the phosphorylation of GSK3β

BACKGROUND

Preclinical and clinical evidence indicates that proton pump inhibitors (PPIs) may indirectly diminish the microbiome diversity, thereby reducing the effectiveness of immune checkpoint inhibitors (ICIs). Conversely, recent publications have shown that PPIs could potentially enhance the response to ICIs. The precise mechanism through which PPIs modulate the ICIs remains unclear. In this study, we discovered a novel molecular function of PPIs in regulating immune invasion, specifically through inducing PD-L1 translocation in various tumor cells.

METHODS

C57BL/6 mice subcutaneous transplantation model is used to verify the potential efficacy of PPIs and PD-L1 antibody. Western blotting analysis and phosphorylated chip are used to verify the alteration of PD-L1-related pathways after being treated with PPIs. The related gene expression is performed by qRT-PCR and luciferase reporter analysis. We also collected 60 clinical patients diagnosed with esophageal cancer or reflux esophagitis and then detected the expression of PD-L1 in the tissue samples by immunohistochemistry.

RESULTS

We observed that the IC50 of tumor cells in response to PPIs was significantly higher than that of normal epithelial cells. PPIs significantly increased the expression of PD-L1 on cell membrane at clinically relevant concentrations. Furthermore, pre-treatment with PPIs appeared to synergize the efficiency of anti-PD-L1 antibodies in mouse models. However, PPI administration did not alter the transcription or total protein level of PD-L1 in multiple tumor cells. Using a phosphorylated protein chip, we identified that PPIs enhanced the phosphorylation of GSK3β, then leading to PD-L1 protein translocation to the cell membranes. The capacity of PPIs to upregulate PD-L1 was negated following GSK3β knockout. Furthermore, our clinical data showed that the PPIs use resulted in increased PD-L1 expression in esophageal cancer patients.

CONCLUSION

We mainly address a significant and novel mechanism that the usage of PPIs could directly induce the expression of PD-L1 by inducing GSK3β phosphorylation and facilitate primary tumor progression and metastasis.

Proton Pump Inhibitors and Cancer Risk: A Comprehensive Review of Epidemiological and Mechanistic Evidence

Background: Proton pump inhibitors (PPIs) are commonly prescribed long-acting drugs used to treat acid reflux, gastroesophageal reflux disease (GERD), and peptic ulcers. Recently, concerns have been raised about their safety, particularly due to the association between long-term PPI use and cancer development. Multiple comprehensive studies have consistently suggested a noteworthy link between prolonged PPI usage and an increased risk of developing gastric, esophageal, colorectal, and pancreatic cancers, yet the precise underlying mechanism remains elusive. Methods: First, we review the extensive body of research that investigates the intricate relationship between cancer and PPIs. Then, we predict PPI toxicity using the prodrug structures with the ProTox-II webserver. Finally, we predict the relative risk of cancer for each PPI, using PubMed citation counts of each drug and keywords related to cancer. Results: Our review indicates that prolonged PPI use (exceeding three months) is significantly associated with an elevated risk of cancer, while shorter-term usage (less than three months) appears to pose a comparatively lower risk. Our review encompasses various proposed mechanisms, such as pH and microbiome alterations, vitamin and mineral malabsorption, hypergastrinemia, and enterochromaffin-like cell proliferation, while ProTox-II also suggests aryl hydrocarbon receptor binding. Potentially, the PubMed citations count suggests that the PPIs omeprazole and lansoprazole are more associated with cancer than pantoprazole and esomeprazole. In comparison, the H2R blocker, famotidine, is potentially less associated with cancer than PPIs, and may serve as a safer alternative treatment for periods beyond 3 months. Conclusions: Despite the well-established cancer risk associated with PPIs, it is notable that these medications continue to be widely prescribed for periods longer than 3 months. Thus, it is of paramount importance for clinicians and patients to thoughtfully evaluate the potential risks and benefits of long-term PPI usage and explore alternative treatments before making informed decisions regarding their medical management.

Helicobacter pylori infection: a dynamic process from diagnosis to treatment

Helicobacter pylori, a gram-negative microaerophilic pathogen, causes several upper gastrointestinal diseases, such as chronic gastritis, peptic ulcer disease, and gastric cancer. For the diseases listed above, H. pylori has different pathogenic mechanisms, including colonization and virulence factor expression. It is essential to make accurate diagnoses and provide patients with effective treatment to achieve positive clinical outcomes. Detection of H. pylori can be accomplished invasively and noninvasively, with both having advantages and limitations. To enhance therapeutic outcomes, novel therapeutic regimens, as well as adjunctive therapies with probiotics and traditional Chinese medicine, have been attempted along with traditional empiric treatments, such as triple and bismuth quadruple therapies. An H. pylori infection, however, is difficult to eradicate during treatment owing to bacterial resistance, and there is no commonly available preventive vaccine. The purpose of this review is to provide an overview of our understanding of H. pylori infections and to highlight current treatment and diagnostic options.

Transcriptional analysis of Helicobacter pylori cytotoxic-associated gene-pathogenicity island in response to different pH levels and proton pump inhibitor exposure

BACKGROUND

Long-term use of proton pump inhibitors (PPIs) can increase the risk of gastric cancer in Helicobacter pylori-infected patients; nevertheless, there is no data about their impact on the pathogenicity of H. pylori. This study aimed at investigating the transcriptional alteration of key gene mediators of cytotoxin-associated gene-pathogenicity island (cag-PAI) among clinical H. pylori isolates in response to omeprazole at different pH levels.

METHODS

Accordingly, H. pylori isolates with the same virulence genotypes selected from the gastric biopsies of patients and transcriptional alteration in the cag-PAI genes studied in the presence or absence of omeprazole (2 mg/mL) at pH 2.0, 4.0 and 7.0 after 30 and 90 minutes of the treatment. Relative changes in the transcriptional levels were recorded in each assay, separately.

RESULTS

Of 18 H. pylori isolates, the cag-PAI empty site was detected in four strains, while the presence of cagA, cagL and cagY was characterized in 77.7%, 83.3% and 83.3% of the cag-PAI-positive strains, respectively. Transcriptional analysis of the selected strains showed up-regulation of cagA and cagL, mainly at pH 2.0 and 4.0 after 30 and 90-minute exposure. A diversity in the expression levels of cag-PAI genes was seen among the strains at the extent and time of induction.

CONCLUSION

Our results showed that omeprazole could increase the expression of H. pylori cagA and cagL at acidic pH. Heterogeneity among the strains probably has an impact on the extent of their interplay with PPIs. Further studies are needed to establish this correlation.

Gastric cancer risk in the elderly is associated with omeprazole use and inversely associated with aspirin use

BACKGROUND

The association between long-term omeprazole use and gastric cancer (GC) risk is controversial. The aim of this study was to investigate the incidence of GC in elderly community-dwelling omeprazole chronic users with/without aspirin compared to non-users.

METHODS

The registry of a large health management organization was searched for all community-dwelling members aged ≥65 years from January 2002 to December 2016. Data on demographics, background parameters, and chronic omeprazole and aspirin use (>11 prescriptions/year) were retrieved. Those diagnosed with new-onset GC during the study period (from January 2003) were identified.

RESULTS

Of 51 405 subjects who met the inclusion criteria, 197 were diagnosed with GC during a mean follow-up period of 8.74 ± 4.16 years. This group accounted for 0.7% of PPI chronic users (72/11 008) and 0.3% (125/40 397) of nonusers (P < 0.001). GC risk was directly associated with omeprazole chronic use [hazard ratio (HR) 2.03, 95% confidence interval (CI): 1.51-2.73, P < 0.001] and inversely associated with aspirin chronic use (HR 0.55, 95% CI: 0.40-0.75, P < 0.001). Each year of omeprazole use increased GC risk by 9%, and each year of aspirin use decreased GC risk by 10% among omeprazole chronic users. The lowest rate of GC was found in omeprazole nonusers/ aspirin chronic users, and the highest, in omeprazole chronic users/aspirin nonusers.

CONCLUSION

Higher GC rate was associated with omeprazole chronic use and inversely associated with aspirin chronic use relative to omeprazole nonuse in community-dwelling elderly.

Tumor microenvironment-regulating nanomedicine design to fight multi-drug resistant tumors

The tumor microenvironment (TME) is a very cunning system that enables tumor cells to escape death post-traditional antitumor treatments through the comprehensive effect of different factors, thereby leading to drug resistance. Deep insights into TME characteristics and tumor resistance encourage the construction of nanomedicines that can remodel the TME against drug resistance. Tremendous interest in combining TME-regulation measurement with traditional tumor treatment to fight multidrug-resistant tumors has been inspired by the increasing understanding of the role of TME reconstruction in improving the antitumor efficiency of drug-resistant tumor therapy. This review focuses on the underlying relationships between specific TME characteristics (such as hypoxia, acidity, immunity, microorganisms, and metabolism) and drug resistance in tumor treatments. The exciting antitumor activities strengthened by TME regulation are also discussed in-depth, providing solutions from the perspective of nanomedicine design. This article is categorized under: Therapeutic Approaches and Drug Discovery > Emerging Technologies Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease Nanotechnology Approaches to Biology > Nanoscale Systems in Biology.

Use of proton pump inhibitors for the risk of gastric cancer

BACKGROUND

This study aimed to systematically analyze the association between long-term use of proton pump inhibitors (PPIs) and the risk of gastric cancer (GC).

METHODS

We performed a systematic search of articles on the relationship between long-term use of PPIs and the risk of GC from PubMed and EMBASE. We calculated the pooled odds ratio of GC in PPI users compared to non-PPI users using random-effects models.

RESULTS

This meta-analysis included 18 studies from 20 different databases with 4348,905 patients enrolled. In the random effects model, we found that an increased risk of GC among PPI users (OR = 1.94; 95% CI [1.43, 2.64]). The long-term use of PPIs compared with histamine-2 receptor antagonist users did not increase the risk of GC (OR = 1.65; 95% CI [0.92, 2.97]). Stratified analysis showed that PPI users had a significantly increased risk of noncardia GC (OR = 2.53; 95% CI [2.03, 3.15]), but had a relatively small relationship with the risk of gastric cardia cancer. (OR = 1.79; 95% CI [1.06, 3.03]). With the extension of PPI use time, the estimated risk value decreases (<1 year: OR = 6.33, 95% CI [3.76, 10.65]; 1-3 years: OR = 1.82, 95% CI [1.30, 2.55]; >3 years: OR = 1.25, 95% CI [1.00, 1.56]). Despite Helicobacter pylori eradication, the long-term use of PPIs did not alter the increased risk of GC (OR = 2.29; 95% CI [1.57, 3.33]).

CONCLUSION

Our meta-analysis found that PPI use may be associated with an increased risk of GC. Further research on the causal relationship between these factors is necessary.

Proton Pump Inhibitors and Cancer Risk: An Umbrella Review and Meta-analysis of Observational Studies

OBJECTIVES

Increasing evidence suggested that proton pump inhibitors (PPIs) use might affect the development of cancers, but previous conclusions remain controversial. Therefore, an umbrella review was performed to clarify the associations between PPIs and various types of cancer by summarizing the existing meta-analyses and systematic reviews.

METHODS

We searched PubMed, Cochrane Library, Embase, CNKI, Wanfang, and VIP database up to June 2022 for eligible meta-analyses or systematic reviews. The summary effect size, 95% CI, heterogeneity, small study effect, and 95% prediction interval were considered in the present study. A Measurement Tool to Assess Systematic Review 2 and grading of recommendation, assessment, development, and evaluation were used to assess methodological quality and evidence.

RESULTS

The umbrella review included 21 meta-analyses containing 65 studies and 10 cancer types with 6.8 million subjects. The results showed that PPI use was significantly associated with increased risks of certain types of cancer, including gastric cancer (odds ratio [OR]: 2.07; 95% CI, 1.30 to 3.29), pancreatic cancer (OR: 1.73; 95% CI, 1.23 to 2.44), colorectal cancer (OR: 1.84; 95% CI, 1.26 to 2.67), and liver cancer (OR: 1.80; 95% CI, 1.27 to 2.54), but was not associated with esophageal cancer. In addition, PPI use was associated with decreased risk of breast cancer (OR: 0.69; 95% CI, 0.50 to 0.96).

CONCLUSIONS

These findings suggested that clinicians should pay more attention to the occurrence of gastric cancer, pancreatic cancer, colorectal cancer, and liver cancer in patients who used PPIs, and PPI prescription should be written only when an accurate specific diagnosis has been made. Furthermore, additional PPIs to the treatment regimen may be benefit for women with a higher-than-average risk of breast cancer.

Proton Pump Inhibitor Use and Risk of Gastric Cancer: Current Evidence from Epidemiological Studies and Critical Appraisal

Proton pump inhibitors (PPIs) are used for maintaining or improving gastric problems. Evidence from observational studies indicates that PPI therapy is associated with an increased risk of gastric cancer. However, the evidence for PPIs increasing the risk of gastric cancer is still being debated. Therefore, we aimed to investigate whether long-term PPI use is associated with an increased risk of gastric cancer. We systematically searched the relevant literature in electronic databases, including PubMed, EMBASE, Scopus, and Web of Science. The search and collection of eligible studies was between 1 January 2000 and 1 July 2021. Two independent authors were responsible for the study selection process, and they considered only observational studies that compared the risk of gastric cancer with PPI treatment. We extracted relevant information from selected studies, and assessed the quality using the Newcastle−Ottawa scale (NOS). Finally, we calculated overall risk ratios (RRs) with 95% confidence intervals (CIs) of gastric cancer in the group receiving PPI therapy and the control group. Thirteen observational studies, comprising 10,557 gastric cancer participants, were included. Compared with patients who did not take PPIs, the pooled RR for developing gastric cancer in patients receiving PPIs was 1.80 (95% CI, 1.46−2.22, p < 0.001). The overall risk of gastric cancer also increased in patients with gastroesophageal reflux disease (GERD), H. pylori treatment, and various adjusted factors. The findings were also consistent across several sensitivity analyses. PPI use is associated with an increased risk of gastric cancer in patients compared with those with no PPI treatment. The findings of this updated study could be used in making clinical decisions between physicians and patients about the initiation and continuation of PPI therapy, especially in patients at high risk of gastric cancer. Additionally, large randomized controlled trials are needed to determine whether PPIs are associated with a higher risk of gastric cancer.

Molecular Mechanism of the Effect of Zhizhu Pill on Gastroesophageal Reflux Disease Based on Network Pharmacology and Molecular Docking

Background

To investigate the pharmacological mechanism of Zhizhu pill (ZZP) against gastroesophageal reflux disease (GERD), network pharmacology in combination with molecular docking was applied in this study.

Methods

Active compounds of ZZP and target genes related to GERD were identified through public databases. Subsequently, the obtained data were used as a basis for further network pharmacological analysis to explore the potential key active compounds, core targets, and biological processes involved in ZZP against GERD. Finally, the results predicted by network pharmacology were validated by molecular docking.

Results

Twenty active components of ZZP were identified to act on 59 targets related to GERD. Enrichment analysis revealed that multiple biological processes including response to oxygen levels, response to oxidative stress, and response to reactive oxygen species were involved in the GERD ZZP treatment with ZZP. ZZP had an impact on the prognosis of GERD mainly through the HIF-1 signaling pathway, PI3K-Akt signaling pathway, and pathways in cancer. Further analysis identified the key components and core targets of ZZP against GERD, of which nobiletin, didymin, luteolin, and naringenin were key components, and PPARG, MMP9, JUN, TP53, PTGS2, EGFR, MAPK3, CASP3, AKT1, and VEGFA were the core targets. Molecular docking verified the stable bonds formed between the key components and the core targets.

Conclusions

The results of this study predict that the therapeutic effects of ZZP in GERD are mediated at least in part via PPARG, MMP9, JUN, TP53, PTGS2, EGFR, MAPK3, CASP3, AKT1, and VEGFA. These results may be useful in providing an experimental basis and new ideas for further research on ZZP in GERD.

Identification of hub pathways and drug candidates in gastric cancer through systems biology

Gastric cancer is the fourth cause of cancer death globally, and gastric adenocarcinoma is its most common type. Efforts for the treatment of gastric cancer have increased its median survival rate by only seven months. Due to the relatively low response of gastric cancer to surgery and adjuvant therapy, as well as the complex role of risk factors in its incidences, such as protein-pomp inhibitors (PPIs) and viral and bacterial infections, we aimed to study the pathological pathways involved in gastric cancer development and investigate possible medications by systems biology and bioinformatics tools. In this study, the protein-protein interaction network was analyzed based on microarray data, and possible effective compounds were discovered. Non-coding RNA versus coding RNA interaction network and gene-disease network were also reconstructed to better understand the underlying mechanisms. It was found that compounds such as amiloride, imatinib, omeprazole, troglitazone, pantoprazole, and fostamatinib might be effective in gastric cancer treatment. In a gene-disease network, it was indicated that diseases such as liver carcinoma, breast carcinoma, liver fibrosis, prostate cancer, ovarian carcinoma, and lung cancer were correlated with gastric adenocarcinoma through specific genes, including hgf, mt2a, mmp2, fbn1, col1a1, and col1a2. It was shown that signaling pathways such as cell cycle, cell division, and extracellular matrix organization were overexpressed, while digestion and ion transport pathways were underexpressed. Based on a multilevel systems biology analysis, hub genes in gastric adenocarcinoma showed participation in the pathways such as focal adhesion, platelet activation, gastric acid secretion, HPV infection, and cell cycle. PPIs are hypothesized to have a therapeutic effect on patients with gastric cancer. Fostamatinib seems a potential therapeutic drug in gastric cancer due to its inhibitory effect on two survival genes. However, these findings should be confirmed through experimental investigations.

Roles and action mechanisms of bile acid-induced gastric intestinal metaplasia: a review

Gastric intestinal metaplasia (IM) is a precancerous lesion that increases the risk of subsequent gastric cancer (GC) development. Therefore, the mechanism of IM has been the focus of basic and clinical research. Helicobacter pylori (H. pylori) infection has been recognized as the main pathogenesis of gastric IM. However, more and more studies have shown that chronic inflammation of gastric mucosa caused by bile reflux is the key pathogenic factor of gastric IM. Bile reflux activates the expression of IM biomarkers via the bile acid receptor. In addition, microRNAs, exosomes, and epigenetics are also involved in the occurrence and development of bile acid-induced gastric IM. Currently, the relevant research is still very few. The molecular mechanism of the phenotypic transformation of gastrointestinal epithelial cells induced by bile acids has not been fully understood. This article mainly reviews the physiology and pathology of bile acid, mechanism of gastric IM induced by bile acid, bile acid receptors, and so on, in order to provide reference for further research.

SAFETY OF LONG-TERM PROTON PUMP INHIBITORS: FACTS AND MYTHS

BACKGROUND

Proton pump inhibitors (PPIs) are one of the most prescribed drugs in the world. Frequent use and long-term maintenance of these drugs drew the attention of researchers for sporadic adverse effects reports.

OBJECTIVE

The purpose of this narrative review is to discuss appropriate data and causality related to these adverse events and PPIs.

METHODS

A narrative review was conducted by systematizing information about safety and adverse events on PPIs from 2015 to 2020. A structured search on Pubmed was performed to identify systematic reviews and meta-analysis investigating the following situations: a) gastric cancer; b) micronutrients deficiency; c) acid rebound; d) infections; e) fractures; f) dementia; g) kidney disease; and h) sudden death and cardiovascular changes.

RESULTS

Recent studies have potentially associated PPIs with some adverse events as osteoporosis-related fractures. There are also reports of intestinal infections, including Clostridium difficile, besides poor vitamins absorption and minerals such as vitamin B12, magnesium, and iron. Furthermore, there are some dementia, pneumonia, kidney disease, myocardial infarction, and stroke reports. For kidney diseases, studies consistently suggest that the use of PPI may be associated with an increased risk of adverse kidney events, especially in the elderly, with long-term PPI use and pre-existing kidney disease. Another additional question is whether chronic PPI use would also lead to the onset of gastric cancer. The abrupt discontinuation of PPIs is also related to increased gastric acid production above pre-PPI treatment levels; this phenomenon is called acid rebound.

CONCLUSION

The key to mitigate adverse effects is the rational use of PPIs at the lowest effective dose and in the shortest possible duration. Although these adverse effects have a potential clinical impact, their causal association is still subject to validation.

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

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

Association between proton pump inhibitor use and gastric cancer: a population-based cohort study using two different types of nationwide databases in Korea

OBJECTIVE

The association between proton pump inhibitor (PPI) use and gastric cancer related to Helicobacter pylori eradication has not been fully investigated in geographical regions with high risk of gastric cancer. We aimed to evaluate the association between PPIs and gastric cancer in Korea.

DESIGN

This study analysed the original and common data model versions of the Korean National Health Insurance Service database from 2002 to 2013. We compared the incidence rates of gastric cancer after 1-year drug exposure, between new users of PPIs and other drugs excluding PPIs, by Cox proportional hazards model. We also analysed the incidence of gastric cancer among PPI users after H. pylori eradication.

RESULTS

The analysis included 11 741 patients in matched PPI and non-PPI cohorts after large-scale propensity score matching. During a median follow-up of 4.3 years, PPI use was associated with a 2.37-fold increased incidence of gastric cancer (PPI≥30 days vs non-PPI; 118/51 813 person-years vs 40/49 729 person-years; HR 2.37, 95% CI 1.56 to 3.68, p=0.001). The incidence rates of gastric cancer showed an increasing trend parallel to the duration of PPI use. In H. pylori-eradicated subjects, the incidence of gastric cancer was significantly associated with PPI use over 180 days compared with the non-PPI group (PPI≥180 days vs non-PPI; 30/12 470 person-years vs 9/7814 person-years; HR 2.22, 95% CI 1.05 to 4.67, p=0.036).

CONCLUSION

PPI use was associated with gastric cancer, regardless of H. pylori eradication status. Long-term PPIs should be used with caution in high-risk regions for gastric cancer.

Association between proton pump inhibitors after percutaneous coronary intervention and risk of gastric cancer

BACKGROUND

Previous studies showing an association between chronic use of proton pump inhibitor (PPI) and gastric cancer are limited by confounding by indication. This relationship has not been studied in patients receiving PPI for prophylaxis, such as those undergoing percutaneous coronary intervention (PCI).

METHOD

This was a retrospective cohort study including 14 hospitals under the Hospital Authority of Hong Kong between 1 January 2004 and 31 December 2017. Participants were patients who underwent first-ever PCI, were not on PPI prescription within 30 days before admission for PCI, had no known malignancy and survived for 365 days after PCI. Propensity score matching was used to balance baseline characteristics and other prescription patterns. The primary outcome was diagnosis of gastric cancer made >365 days after PCI as a time-to-first-event analysis. The secondary outcome was death from gastric cancer.

RESULTS

Among the 13 476 patients (6738 pairs) matched by propensity score, gastric cancer developed in 17 (0.25%) PPI users and 7 (0.10%) PPI non-users after a median follow-up of 7.1 years. PPI users had a higher risk of gastric cancer (HR 3.55; 95% CI 1.46 to 8.66, p=0.005) and death from gastric cancer (HR 4.18; 95% CI 1.09 to 16.08, p=0.037), compared with non-users. The association was duration-dependent and patients who took PPI for ≥365 days were at increased risk.

CONCLUSIONS

Chronic use of PPI was significantly associated with increased risk of gastric cancer and death from gastric cancer in patients for whom it was prescribed as prophylaxis. Physicians should judiciously assess the relevant risks and benefits of chronic PPI use before prescription.

Association of Helicobacter pylori Infection and Host Cytokine Gene Polymorphism with Gastric Cancer

The global cancer burden of new cases of various types rose with millions of death in 2018. Based on the data extracted by GLOBOCAN 2018, gastric cancer (GC) is the third leading cause of mortality related to cancer across the globe. Carcinogenic or oncogenic infections associated with Helicobacter pylori (Hp) are regarded as one of the essential risk factors for GC development. It contributes to the increased production of cytokines that cause inflammation prior to their growth in the host cells. Hp infections and specific types of polymorphisms within the host cells encoding cytokines are significant contributors to the host's increased susceptibility in terms of the development of GC. Against the backdrop of such an observation is that only a small portion of the cells infected can become malignant. The diversities are a consequence of the differences in the pathogenic pathway of the Hp, susceptibility of the host, environmental conditions, and interplay between these factors. It is evident that hosts carrying cytokine genes with high inflammatory levels and polymorphism tend to exhibit an increased risk of development of GC, with special emphasis being placed on the host cytokines gene polymorphisms.

Dose-dependent association of proton pump inhibitors use with gastric intestinal metaplasia among Helicobacter pylori-positive patients

BACKGROUND

Gastric intestinal metaplasia is a pre-cancerous condition associated with multiple factors.

OBJECTIVE

We evaluated whether cumulative proton pump inhibitor dose is associated with the diagnosis of gastric intestinal metaplasia while controlling for multiple variables.

METHODS

We retrospectively identified patients who underwent upper endoscopy with gastric biopsy between 2005 and 2014. Covariate data retrieved included age, sex, ethnicity, smoking status, Helicobacter pylori status (based on clarithromycin-amoxicillin-proton pump inhibitor issued), cumulative proton pump inhibitor issued within 10 years (quartiles [PPI-Q1-4 ] of daily drug dose), anti-parietal cell antibodies, body mass index and comorbidity index.

RESULTS

Of the 14,147 included patients (median age 63.4 years; women 54.4%; Helicobacter pylori-positive 29.0%), 1244 (8.8%) had gastric intestinal metaplasia. Increasing age, Helicobacter pylori infection, smoking, anti-parietal cell antibodies and proton pump inhibitor use were all associated with the diagnosis of gastric intestinal metaplasia. Upper quartiles of cumulative proton pump inhibitor doses (PPI-Q4 and PPI-Q3 vs. PPI-Q1 ) were associated with the diagnosis of gastric intestinal metaplasia: adjusted odds ratios 1.32 (95% confidence interval [CI] 1.111.57) and 1.27 (95% CI 1.07-1.52), respectively, for the whole cohort (Ptotal 0.007, Ptrend 0.013), 1.69 (95% CI 1.23-2.33) and 1.40 (95% CI 1.04-1.89), respectively, for Helicobacter pylori-positive patients (Ptotal 0.004, Ptrend 0.005) and 1.21 (95% CI 0.98-1.49) and 1.20 (95% CI 0.96-1.49), respectively, for Helicobacter pylori-negative patients (Ptotal 0.288, Ptrend 0.018). Upper quartiles of proton pump inhibitor dose were associated with a 5-10-fold increased risk of low-grade dysplasia.

CONCLUSIONS

Among Helicobacter pylori-positive patients, proton pump inhibitor use appears to be associated with a dose-dependent increased likelihood of gastric intestinal metaplasia.

Time trends in incidence and survival of small intestinal cancer in Sweden

BACKGROUND

Small intestinal cancer is less common than some other gastrointestinal malignancies. Tumours of different histological types and anatomical sites of origin have therefore often been described together. The aim of this study was to investigate the epidemiology for each of the four main subtypes: duodenal adenocarcinoma (D-AC), duodenal neuroendocrine tumour (D-NET), jejunoileal adenocarcinoma (J/I-AC), and jejunoileal neuroendocrine tumour (J/I-NET).

METHODS

All patients with small intestinal cancer diagnosed between 1960 and 2015 were identified from the Swedish Cancer Register. The age-adjusted incidence rate with incidence rate ratios, as well as overall (OS) and net (NS) survival, were determined and temporal trends were analysed.

RESULTS

The incidence rate was highest for J/I-NET, with 9.98 clinical diagnoses per million in 2010-2015. Clinical diagnosis of D-AC increased more than 10-fold and surpassed J/I-AC as the second most common subtype. D-NET was by far the least common subtype. Diagnosis at autopsy became less common over time, whereas clinical diagnoses increased significantly for all four subtypes. All subtypes except J/I-AC affected men more often than women. The age distribution was similar between subtypes, although patients with adenocarcinomas were slightly older. Survival was generally much better for patients with NET than for those with adenocarcinoma. Both OS and NS showed a negative association with advancing age. Survival improved only for J/I-NET from a 5-year NS of 0.69 in the 1960s to 0.81 in 2010-2015.

CONCLUSION

The incidence of small intestinal cancer is increasing, particularly for D-AC and in the elderly. Survival of patients with small intestinal cancer has improved only for J/I-NET over the last decades.

RNA Sequencing of Early-Stage Gastric Adenocarcinoma Reveals Multiple Activated Pathways and Novel Long Non-Coding RNAs in Patient Tissue Samples

Background

Gastric cancer is among the most common cancers worldwide that currently lacks effective diagnostic biomarkers and therapeutic targets. Next-generation RNA sequencing is a powerful tool that allows rapid and accurate transcriptome-wide profiling to detect differentially expressed transcripts involved in normal biological and pathological processes. Given the function of this technique, it has the potential to identify new molecular targets for the early diagnosis of disease, particularly in gastric adenocarcinoma.

Methods

In this study, whole-transcriptome analysis was performed with RNA sequencing on tumoral and non-tumoral tissue samples from patients with early-stage gastric cancer. Gene ontology and pathway enrichment analysis were used to determine the main function of the specific genes and pathways present in tissue samples.

Results

Analysis of the differentially expressed genes revealed 5 upregulated and 234 downregulated genes in gastric cancer tissues. Pathway enrichment analysis revealed significantly dysregulated signalling pathways, including those involved in gastric acid secretion, drug metabolism and transporters, molecular toxicology, O-linked glycosylation of mucins, immunotoxicity, metabolism of xenobiotics by cytochrome P450, and glycosylation. We also found novel downregulated non-coding RNAs present in gastric cancer tissues, including GATA6 antisense RNA 1, antisense to LYZ, antisense P4HB, overlapping ACER2, long intergenic non-protein coding RNA 2688 (LINC02688) and uncharacterized LOC25845 (PP7080).

Conclusion

The transcriptomic data found in this study illustrates the power of RNA-sequencing in discovering novel genes ‎and tumorigenic pathways involved in human carcinogenesis. The anomalies present in these genes may serve as promising tools for the development of accurate diagnostic biomarkers for the detection of early-stage gastric cancer.

Towards Understanding of Gastric Cancer Based upon Physiological Role of Gastrin and ECL Cells

Simple Summary

Generally, we know that cancers represent genetic changes in tumour cells, but we most often do not know the causes of cancers or how they develop. Our knowledge of the regulation of gastric acid secretion is well known, with the gastric hormone gastrin maintaining gastric acidity by stimulation of the enterochromaffin-like (ECL) cell to release histamine, which subsequently augments acid secretion. Furthermore, it seems to be a general principle that stimulation of function (which, for the ECL cell, is release of histamine) in a parallel way stimulates the proliferation of the same cell. Long-term hyperstimulation of cell division predisposes to genetic changes and, thus, development of tumours. All conditions with reduced gastric acidity result in an increased risk of gastric tumours due to elevated gastrin in order to restore gastric acidity. It is probable that Helicobacter pylori infection (the most important cause of gastric cancer), as well as drugs inhibiting gastric acid secretion induce gastric cancer in the long-term, due to an elevation of gastrin caused by reduced gastric acidity. Gastric carcinomas have been shown to express ECL cell markers, further strengthening this relationship.

Abstract

The stomach is an ideal organ to study because the gastric juice kills most of the swallowed microbes and, thus, creates rather similar milieu among individuals. Combined with a rather easy access to gastric juice, gastric physiology was among the first areas to be studied. During the last century, a rather complete understanding of the regulation of gastric acidity was obtained, establishing the central role of gastrin and the histamine producing enterochromaffin-like (ECL) cell. Similarly, the close connection between regulation of function and proliferation became evident, and, furthermore, that chronic overstimulation of a cell with the ability to proliferate, results in tumour formation. The ECL cell has long been acknowledged to give rise to neuroendocrine tumours (NETs), but not to play any role in carcinogenesis of gastric adenocarcinomas. However, when examining human gastric adenocarcinomas with the best methods presently available (immunohistochemistry with increased sensitivity and in-situ hybridization), it became clear that many of these cancers expressed neuroendocrine markers, suggesting that some of these tumours were of neuroendocrine, and more specifically, ECL cell origin. Thus, the ECL cell and its main regulator, gastrin, are central in human gastric carcinogenesis, which make new possibilities in prevention, prophylaxis, and treatment of this cancer.

Helicobacter pylori Related Diseases and Osteoporotic Fractures (Narrative Review)

Osteoporosis (OP) and osteoporotic fractures (OFs) are common multifactorial and heterogenic disorders of increasing incidence. Helicobacter pylori (H.p.) colonizes the stomach approximately in half of the world's population, causes gastroduodenal diseases and is prevalent in numerous extra-digestive diseases known to be associated with OP/OF. The studies regarding relationship between H.p. infection (HPI) and OP/OFs are inconsistent. The current review summarizes the relevant literature on the potential role of HPI in OP, falls and OFs and highlights the reasons for controversies in the publications. In the first section, after a brief overview of HPI biological features, we analyze the studies evaluating the association of HPI and bone status. The second part includes data on the prevalence of OP/OFs in HPI-induced gastroduodenal diseases (peptic ulcer, chronic/atrophic gastritis and cancer) and the effects of acid-suppressive drugs. In the next section, we discuss the possible contribution of HPI-associated extra-digestive diseases and medications to OP/OF, focusing on conditions affecting both bone homeostasis and predisposing to falls. In the last section, we describe clinical implications of accumulated data on HPI as a co-factor of OP/OF and present a feasible five-step algorithm for OP/OF risk assessment and management in regard to HPI, emphasizing the importance of an integrative (but differentiated) holistic approach. Increased awareness about the consequences of HPI linked to OP/OF can aid early detection and management. Further research on the HPI-OP/OF relationship is needed to close current knowledge gaps and improve clinical management of both OP/OF and HPI-related disorders.

Omeprazole and adenocarcinoma in the stomach of rats submitted to duodenogastric reflux. Is there a protective effect?

Purpose:

To investigate the role of omeprazole and nitrites on the gastric mucosa of rats submitted to specific techniques to induce duodenogastric reflux.

Methods:

One hundred and twenty Wistar rats were divided into three groups: Group I (n=40) -gastrotomy; Group II (n=40) - duodenogastric reflux after gastrojejunoanastomosis latero-lateral (DGR); Group III (n=40) - retrograde duodenogastric reflux through the pylorus (DGR-P). The groups were divided into 4 subgroups of 10 animals, respectively treated for 16 weeks with water, omeprazole 1.6 mg / rat / day, nitrite 600 mg / kg / day and omeprazole plus nitrite simultaneously.

Results:

The proliferative lesions found were: squamous hyperplasia - 69.1%, adenomatous hyperplasia in the anastomosis - 29.1% and prepyloric adenomatous hyperplasia - 42.5%. Adenocarcinomas were registered in 7 animals (5.8%): one in Group I (omeprazole plus nitrite), two in Group II (omeprazole and nitrite plus omeprazole) and four in Group III (water, nitrite, omeprazole and omeprazole plus nitrite).

Conclusions:

The occurrence of squamous hyperplasia, adenomatous hyperplasia and adenocarcinoma increased after gastrojejunal anastomoses, which cause duodenogastric reflux. The association of omeprazole did not protect the development of proliferative lesions and cancer induced by duodenogastric reflux in rats.

Potential proton pump inhibitor-related adverse effects

Proton pump inhibitors (PPIs) are one of the most common medications taken by patients worldwide. PPIs are used to treat acid-related disorders, including gastroesophageal reflux disease, peptic ulcer disease, Helicobacter pylori infection, and nonsteroidal anti-inflammatory drug/stress ulceration. For some of these diseases, long-term treatment is necessary. With such prolonged use, concern and investigation into potential adverse effects has increased. In addition, data are available regarding potential anticancer effects of PPIs, especially regarding solid tumors. The aim of this review is to assess the literature on PPIs with regard to common concerns, such as drug-drug interactions, the intestinal microbiome, dementia and central nervous system disease, and osteoporosis, as well as to highlight potential negative and positive impacts of the drug in cancer.