Helicobacter Pylori Infection and Lung Cancer: New Insights and Future Challenges

Effects and mechanisms of Helicobacter pylori infection on the occurrence of extra-gastric tumors

Helicobacter pylori (H. pylori) colonizes the human stomach and many studies have discussed the mechanisms of H. pylori infection leading to gastric diseases, including gastric cancer. Additionally, increasing data have shown that the infection of H. pylori may contribute to the development of extra-gastric diseases and tumors. Inflammation, systemic immune responses, microbiome disorders, and hypergastrinemia caused by H. pylori infection are associated with many extra-gastric malignancies. This review highlights recent discoveries; discusses the relationship between H. pylori and various extra-gastric tumors, such as colorectal cancer, lung cancer, cholangiocarcinoma, and gallbladder carcinoma; and explores the mechanisms of extra-gastric carcinogenesis by H. pylori. Overall, these findings refine our understanding of the pathogenic processes of H. pylori, provide guidance for the clinical treatment and management of H. pylori-related extra-gastric tumors, and help improve prognosis.

The role of oral microbiota in cancer

Cancer remains a significant global challenge, with an estimated 47% increase in cancer patients from 2020 to 2040. Increasing research has identified microorganism as a risk factor for cancer development. The oral cavity, second only to the colon, harbors more than 700 bacterial species and serves as a crucial microbial habitat. Although numerous epidemiological studies have reported associations between oral microorganisms and major systemic tumors, the relationship between oral microorganisms and cancers remains largely unclear. Current research primarily focuses on respiratory and digestive system tumors due to their anatomical proximity to the oral cavity. The relevant mechanism research mainly involves 47% dominant oral microbial population that can be cultured in vitro. However, further exploration is necessary to elucidate the mechanisms underlying the association between oral microbiota and tumors. This review systematically summarizes the reported correlations between oral microbiota and common cancers while also outlining potential mechanisms that may guide biological tumor treatment.

Helicobacter pylori and unignorable extragastric diseases: Mechanism and implications

Considered as the most popular pathogen worldwide, Helicobacter pylori is intensively associated with diverse gastric diseases, including gastric ulcers, chronic progressive gastritis, and gastric cancer. Aside from its pathogenic effect on gastric diseases, growing evidences reveal that H. pylori may be related to numerous extragastric diseases. In this article, we reviewed recent studies and systematically elucidated that H. pylori may interfere with many biological processes outside the stomach and influence the occurrence of various extragastric diseases. Many epidemiological studies have indicated that H. pylori plays a pathogenic role in COVID-19, atherosclerosis, hyperemesis gravidarum and several other extragastric diseases, while the effect of H. pylori is currently under investigation in gastroesophageal reflux disease, asthma, and inflammatory bowel disease. Moreover, we also summarized the possible pathogenic mechanisms of H. pylori that may be related to chronic systemic inflammation and molecular mimicker. Taken together, this review provides a new perspective on the role of H. pylori in extragastric diseases and explores the possible mechanisms, which may help guide clinical treatment.

H. pylori Infection and Virulence Factors cagA and vacA (s and m Regions) in Gastric Adenocarcinoma from Pará State, Brazil

H. pylori shows a great variability in genes associated with virulence, which may influence properties related to gastric adenocarcinoma initiation and progression. Among them, cagA and vacA show a strong positive association with the disease. Therefore, a cross-sectional study was carried out with 281 samples of gastric adenocarcinoma, collected at a cancer reference center in the Brazilian Amazon. Detection of H. pylori was proceeded by PCR of the ureA and 16S genes. Positive samples were subjected to the cagA detection and vacA typing. The bacteria were observed in 32.03% of the samples. Positivity for H. pylori was associated with advanced age (p = 0.0093) and metastases (p = 0.0073). Among the positive cases, 80% (72/90) had the cagA gene. For the “s” position of the vacA gene, 98.8% (83/84) of the bacteria had genotype s1 and 1.2% (1/84) were genotyped as s2. For the “m” position, the results were: 63.6% (56/88) with m1 genotype, 2.3% (2/88) genotyped as m2 and 34.1% (30/88) m1/m2. Virulence factors did not impact an increase in the association with age or metastases. In conclusion, H. pylori infection is associated with malignant phenotype cases of gastric adenocarcinoma, involving metastases. The virulence factors related to the cagA and vacA genes showed a high prevalence in the Brazilian Amazon.

Links between Infections, Lung Cancer, and the Immune System

Lung cancer is the leading disease of cancer-related deaths worldwide. Since the beginning of the 20th century, various infectious agents associated with lung cancer have been identified. The mechanisms that include systemic inflammatory pathways as effect of microbial persistence in the lung can secondarily promote the development of lung carcinogenesis. Chronic inflammation associated with lung-cancer infections is known to precede tumor development, and it has a strong effect on the response(s) to therapy. In fact, both viral and bacterial infections can activate inflammatory cells and inflammatory signaling pathways. In this review, an overview of critical findings of recent studies investigating associations between each of viral and bacterial pathogens and lung carcinoma is provided, with particular emphasis on how infectious organisms can interfere with oncogenic processes and all the way through immunity. Moreover, a discussion of the direct crosstalk between lung tumor development and inflammatory processes is also presented.

Enhancement of Antimicrobial and Antiproliferative Activities of Standardized Frankincense Extract Using Optimized Self-Nanoemulsifying Delivery System

Boswellic acids (BAs) are the main bioactive compounds of frankincense, a natural resin obtained from the genus Boswellia. This study aimed to develop a self-nanoemulsifying delivery system (SNEDS) to improve the antimicrobial and antiproliferative activities of standardized frankincense extract (Fr-extract). Fr-extract was standardized, and BA content was quantified using the developed HPLC-UV method. Screening studies of excipients followed by formula optimization using a mixture simplex lattice design was employed. The optimized Fr-SENDS formulation was characterized. Furthermore, microbiological and antiproliferative assessments of the standardized Fr-extract and Fr-SNEDS were evaluated. Quantification demonstrated that the major constituent is 11-keto-boswellic acid (KBA) (16.25%) among BA content (44.96%). The optimized Fr-SENDS (composed of 5% CapryolTM 90, 48.7% Gelucire® 44/14 and 46.3% ethanol) showed spherical nanosized dispersions with DS, PDI, and zeta potential of 17.9 nm, 0.2, and −14.5 mV, respectively. Fr-SNEDS exhibited lower MIC and MBC values compared with Fr-extract against pathogens conjugated with lung cancer and was comparable to reference antimicrobials. Fr-SNEDS showed superior antiproliferative activity over Fr-extract, with IC50 values of 20.49 and 109.5 μg mL−1, respectively. In conclusion, the optimized Fr-SNEDS could be easily developed and manufactured at a low cost and the in vitro results support its use as a potential adjuvant oral therapy for lung cancer. Further in vivo studies could be continued to assess the therapeutic efficiency of the prepared system.

The Effect of Helicobacter pylori on the Presentation and Clinical Course of Coronavirus Disease 2019 Infection

OBJECTIVES

Novel coronavirus 2019 (corona virus disease 2019 [COVID-19]) binds angiotensin-converting enzyme-2 (ACE-2) receptors to enter the cell. These receptors are widely expressed in the intestine, and COVID-19 may cause gastrointestinal symptoms via these receptors during the course of the disease. Helicobacter pylori is known to increase the expression of ACE-2 receptors in the gastrointestinal tract. The aim of this study was to investigate the effects of H pylori on the presentation and clinical course of COVID-19 infections.

METHODS

This study was carried out from June 1 to July 20, 2020. Patients diagnosed with COVID-19 infections by PCR tests were included in the study. Antigen screening tests were performed on stool samples to determine the presence of H pylori. All patients were evaluated for manifestations of COVID-19 infection, severity of the course, hospitalized days because of the virus and outcome of the disease process.

RESULTS

Of 108 COVID-19 positive patients evaluated, 31 with a mean age of 49.54 ± 17.94 years were H pylori-positive (8 girls [25.8%]) and 77 with a mean age of 47.85 ± 20.51 years; (31 girls [40.3%]) were H pylori-negative. Abdominal pain (19.4% vs 2.6%) and diarrhea (32.3% vs 9.1%) were significantly higher in patients with H pylori than those without (P = 0.007 and P = 0.006, respectively). There was no statistically significant difference between H pylori positivity and the number of hospitalized days, the severity of the course of COVID-19 infection, or the outcome of the disease (P > 0.05).

CONCLUSION

Our results revealed that the findings of abdominal pain and diarrhea strongly correlated with the presence of H pylori in COVID-19 patients.

Predictive Effect of Helicobacter pylori in Gastric Carcinoma Development: Systematic Review and Quantitative Evidence Synthesis

Helicobacter pylori (H. pylori) is a bacterial pathogen implicated in gastritis, gastric ulceration, and gastric carcinoma. This study aimed to synthesize literature in providing evidence on the causative role of H. pylori in gastric carcinoma development. This study is based on assessing public literature using an applied meta-analysis, namely, quantitative evidence synthesis (QES). The analytic procedure uses DerSimonian-Laird, including assessing heterogeneity. The QES also utilizes meta-regression and the environmental effect associated with H. pylori in gastric cancer development. Eighteen studies are included in the QES. There is increased prevalence of H. pylori exposure among the cases. The heterogeneity between the CES and individual effect sizes is also significant. Despite controlling for the confoundings, there is increased exposure to H. pylori among the gastric cancer cases, regardless of the differences in the geographic location. H. pylori in this synthesized literature illustrates the contributory role of this microbe in gastric carcinoma. Additionally, regardless of geographic locale, namely, South Korea or Spain, H. pylori is implicated in gastric cancer development.

Role of Lung Microbiome in Innate Immune Response Associated With Chronic Lung Diseases

Respiratory diseases such as asthma, chronic obstructive pulmonary disease (COPD), lung fibrosis, and lung cancer, pose a huge socio-economic burden on society and are one of the leading causes of death worldwide. In the past, culture-dependent techniques could not detect bacteria in the lungs, therefore the lungs were considered a sterile environment. However, the development of culture-independent techniques, particularly 16S rRNA sequencing, allowed for the detection of commensal microbes in the lung and with further investigation, their roles in disease have since emerged. In healthy individuals, the predominant commensal microbes are of phylum Firmicutes and Bacteroidetes, including those of the genera Veillonella and Prevotella. In contrast, pathogenic microbes (Haemophilus, Streptococcus, Klebsiella, Pseudomonas) are often associated with lung diseases. There is growing evidence that microbial metabolites, structural components, and toxins from pathogenic and opportunistic bacteria have the capacity to stimulate both innate and adaptive immune responses, and therefore can contribute to the pathogenesis of lung diseases. Here we review the multiple mechanisms that are altered by pathogenic microbiomes in asthma, COPD, lung cancer, and lung fibrosis. Furthermore, we focus on the recent exciting advancements in therapies that can be used to restore altered microbiomes in the lungs.

The TLR4/ERK/PD‑L1 axis may contribute to NSCLC initiation

Infection and inflammation serve an important role in tumor development. Toll-like receptor 4 (TLR4) is a pivotal component of the innate and adaptive immune response during infection and inflammation. Programmed-death ligand 1 (PD-L1) is hypothesized as an important factor for non-small cell lung cancer (NSCLC) immune escape. In the present study, the relationship between TLR4 and PD-L1, in addition to the associated molecular mechanism, were investigated. TLR4 and PD-L1 expression in lung cancer tissues were detected using immunohistochemistry, whilst overall patient survival was measured using the Kaplan-Meier method. The A549 cell line stimulated using lipopolysaccharide (LPS) was applied as the in vitro inflammatory NSCLC model. Associated factors were investigated using reverse transcription-quantitative PCR and western blotting. Lung cancer tissues exhibited increased PD-L1 and TLR4 levels compared with those of adjacent para-cancerous tissues, where there was a positive correlation between TLR4 and PD-L1 expression. In addition, increased expression of these two proteins was found to be linked with poorer prognoses. Following the stimulation of A549 cells with LPS, TLR4 and PD-L1 expression levels were revealed to be upregulated in a dose-dependent manner, where the ERK and PI3K/AKT signaling pathways were found to be activated. Interestingly, in the presence of inhibitors of these two pathways aforementioned, upregulation of PD-L1 expression was only inhibited by the MEK inhibitor PD98059, which can inhibit ERK activity. These data suggested that the ERK signaling pathway is necessary for the TLR4/PD-L1 axis. In conclusion, data from the present study suggest that TLR4 and PD-L1 expression can serve as important prognostic factors for NSCLC, where TLR4 activation may induce PD-L1 expression through the ERK signaling pathway.

Role of Helicobacter pylori infection in the manifestation of old age-related diseases

Helicobacter pylori is one of the most prevalent infection worldwide. It affects individuals of different age groups. Elderly people tend to resist eradication treatment and worsening of infection can lead to several gastric and non-gastric pathologies. Aging-associated cellular and molecular alteration can increase the risk of other pathologies such as osteoporosis, Alzheimer's disease, Parkinson's disease, respiratory and renal dysfunction, and cancer in geriatric patients, more than other age groups. This review article highlights some of the most common old age diseases and the role of H. pylori infection as a risk factor to worsen the conditions, presented by the molecular evidences of these associations. These studies can help clinicians to understand the underlying pathogenesis of the disease and identify high-risk patients, aiding clearer diagnosis and treatment.