The Double-Edged Sword Role of Viruses in Gastric Cancer

Stomach microbiota in gastric cancer development and clinical implications

Gastric cancer (GC) is one of the most common malignancies and a prominent cause of cancer mortality worldwide. A distinctive characteristic of GC is its intimate association with commensal microbial community. Although Helicobacter pylori is widely recognised as an inciting factor of the onset of gastric carcinogenesis, increasing evidence has indicated the substantial involvement of microbes that reside in the gastric mucosa during disease progression. In particular, dysregulation in gastric microbiota could play pivotal roles throughout the whole carcinogenic processes, from the development of precancerous lesions to gastric malignancy. Here, current understanding of the gastric microbiota in GC development is summarised. Potential translational and clinical implications of using gastric microbes for GC diagnosis, prognosis and therapeutics are also evaluated, with further discussion on conceptual haziness and limitations at present. Finally, we highlight that modulating microbes is a novel and promising frontier for the prevention and management of GC, which necessitates future in-depth investigations.

Elucidating gastric cancer mechanisms and therapeutic potential of Adociaquinone A targeting EGFR: A genomic analysis and Computer Aided Drug Design (CADD) approach

Gastric cancer predominantly adenocarcinoma, accounts for over 85% of gastric cancer diagnoses. Current therapeutic options are limited, necessitating the discovery of novel drug targets and effective treatments. The Affymetrix gene expression microarray dataset (GSE64951) was retrieved from NCBI-GEO data normalization and DEGs identification was done by using R-Bioconductor package. Gene Ontology (GO) analysis of DEGs was performed using DAVID. The protein-protein interaction network was constructed by STRING database plugin in Cytoscape. Subclusters/modules of important interacting genes in main network were extracted by using MCODE. The hub genes from in the network were identified by using Cytohubba. The miRNet tool built a hub gene/mRNA-miRNA network and Kaplan-Meier-Plotter conducted survival analysis. AutoDock Vina and GROMACS MD simulations were used for docking and stability analysis of marine compounds against the 5CNN protein. Total 734 DEGs (507 up-regulated and 228 down-regulated) were identified. Differentially expressed genes (DEGs) were enriched in processes like cell-cell adhesion and ATP binding. Eight hub genes (EGFR, HSPA90AA1, MAPK1, HSPA4, PPP2CA, CDKN2A, CDC20, and ATM) were selected for further analysis. A total of 23 miRNAs associated with hub genes were identified, with 12 of them targeting PPP2CA. EGFR displayed the highest expression and hazard rate in survival analyses. The kinase domain of EGFR (PDBID: 5CNN) was chosen as the drug target. Adociaquinone A from Petrosia alfiani, docked with 5CNN, showed the lowest binding energy with stable interactions across a 50 ns MD simulation, highlighting its potential as a lead molecule against EGFR. This study has identified crucial DEGs and hub genes in gastric cancer, proposing novel therapeutic targets. Specifically, Adociaquinone A demonstrates promising potential as a bioactive drug against EGFR in gastric cancer, warranting further investigation. The predicted miRNA against the hub gene/proteins can also be used as potential therapeutic targets.

Exploring the Microbiome in Gastric Cancer: Assessing Potential Implications and Contextualizing Microorganisms beyond H. pylori and Epstein-Barr Virus

While previous research has primarily focused on the impact of H. pylori and Epstein-Barr virus (EBV), emerging evidence suggests that other microbial influences, including viral and fungal infections, may also contribute to gastric cancer (GC) development. The intricate interactions between these microbes and the host's immune response provide a more comprehensive understanding of gastric cancer pathogenesis, diagnosis, and treatment. The review highlights the roles of established players such as H. pylori and EBV and the potential impacts of gut bacteria, mainly Lactobacillus, Streptococcus, hepatitis B virus, hepatitis C virus, and fungi such as Candida albicans. Advanced sequencing technologies offer unprecedented insights into the complexities of the gastric microbiome, from microbial diversity to potential diagnostic applications. Furthermore, the review highlights the potential for advanced GC diagnosis and therapies through a better understanding of the gut microbiome.

Gastric Cancer and Viruses: A Fine Line between Friend or Foe

Gastric cancer (GC) is a significant health concern worldwide, with a GLOBOCAN estimate of 1.08 million novel cases in 2020. It is the leading cause of disability-adjusted life years lost to cancer, with the fourth most common cancer in males and the fifth most common cancer in females. Strategies are pursued across the globe to prevent gastric cancer progression as a significant fraction of gastric cancers have been linked to various pathogenic (bacterial and viral) infections. Early diagnosis (in Asian countries), and non-invasive and surgical treatments have helped manage this disease with 5-year survival for stage IA and IB tumors ranging between 60% and 80%. However, the most prevalent aggressive stage III gastric tumors undergoing surgery have a lower 5-year survival rate between 18% and 50%. These figures point to a need for more efficient diagnostic and treatment strategies, for which the oncolytic viruses (OVs) appear to have some promise. OVs form a new therapeutic agent class that induces anti-tumor immune responses by selectively killing tumor cells and inducing systemic anti-tumor immunity. On the contrary, several oncogenic viruses have been shown to play significant roles in malignancy progression in the case of gastric cancer. Therefore, this review evaluates the current state of research and advances in understanding the dual role of viruses in gastric cancer.

[Modern views on the role of X gene of the hepatitis B virus (Hepadnaviridae: Orthohepadnavirus: Hepatitis B virus) in the pathogenesis of the infection it causes]

The review presents information on the role of hepatitis B virus (Hepadnaviridae: Orthohepadnavirus: Hepatitis B virus) (HBV) X gene and the protein it encodes (X protein) in the pathogenesis of viral hepatitis B. The evolution of HBV from primordial to the modern version of hepadnaviruses (Hepadnaviridae), is outlined as a process that began about 407 million years ago and continues to the present. The results of scientific works of foreign researchers on the variety of the influence of X protein on the infectious process and its role in the mechanisms of carcinogenesis are summarized. The differences in the effect of the X protein on the course of the disease in patients of different ethnic groups with regard to HBV genotypes are described. The significance of determining the genetic variability of X gene as a fundamental characteristic of the virus that has significance for the assessment of risks of hepatocellular carcinoma (HCC) spread among the population of the Russian Federation is discussed.

Human papillomavirus infection and gastric cancer risk: A meta-epidemiological review

Gastric cancer (GC) is a multifactorial disease, and several modifiable risk factors have been reported. This review summarizes and interprets two previous quantitative systematic reviews evaluating the association between human papillomavirus (HPV) infection and GC risk. The results of two systematic reviews evaluating the same hypothesis showed a statistically significant difference in summary odds ratios and their 95% confidence intervals. Thus, it is necessary to conduct a subgroup analysis of Chinese and non-Chinese studies. Additional meta-analyses that control for heterogeneity are required. Reanalysis showed that all the Chinese studies had statistical significance, whereas the non-national studies did not. The funnel plot asymmetry and Egger's test confirmed publication bias in the Chinese studies. In addition, the proportion of HPV-positive cases in Chinese studies was 1.43 times higher than that in non-Chinese studies and 2.81 times lower in controls. Therefore, the deduced evidence is currently insufficient to conclude that HPV infection is associated with GC risk.

Collagenous Gastritis in Primary Selective IgM Deficiency: Transition to EBV+ Gastric Adenocarcinoma

Selective IgM deficiency (SIgMD) and isolated collagenous gastritis are two independent rare disorders. Our purpose is to report the 1^st case of SIgMD and isolated collagenous gastritis and collagenous gastritis that has transitioned to EBV + gastric adenocarcinoma. Gastric biopsy tissue was analyzed by EBV-related encoded RNA in situ hybridization assay. Subsets of CD4, CD8, T follicular helper cells (T_FH), and members of the “regulatory lymphocytes club” were measured with multiple panels of monoclonal antibodies and isotype controls by multicolor flow cytometry. The patient was diagnosed with SIgMD (extremely low serum IgM 9 mg/dl and normal IgG and IgA and exclusion of secondary causes of low IgM). Soon after SIgMD diagnosis, the patient developed collagenous gastritis and, 8 years later, developed gastric adenocarcinoma that was positive for EBV. An extensive immunological analysis revealed reduced naïve CD4 and CD8 effector memory T cells and increased naïve and central memory CD8 T cells. Among the circulating follicular helper T cells (cT_FH), T_FH1 and T_FH2 were increased whereas T_FH17 was decreased. CD4 Treg cells and T_FR cells were increased, whereas Breg and CD8 Treg were comparable to control. In conclusion, SIgMD may be associated with isolated collagenous gastritis, and collagenous gastritis may transition to EBV + gastric adenocarcinoma. A role of regulatory lymphocytes in gastric cancer is discussed.

Critical review of Epstein-Barr virus microRNAs relation with EBV-associated gastric cancer

Epstein-Barr virus (EBV)-associated gastric cancer (EBVaGC) is regarded as the most prevalent malignant tumor triggered by EBV infection. In recent years, increasing attention has been considered to recognize more about the disease process's exact mechanisms. There is accumulating evidence that showing epigenetic modifications play critical roles in the EBVaGC pathogenesis. MicroRNAs (miRNAs), as critical epigenetic modulators, are single-strand short noncoding RNA (length ~ <200 bp), which regulate gene expression through binding to the 3'-untranslated region (3'-UTR) of target RNA transcripts and either degrade or repress their activities. In the latest research on EBV, it was found that this virus could encode miRNAs. Mechanistically, EBV-encoded miRNAs are involved in carcinogenesis and the progression of EBV-associated malignancies. Moreover, these miRNAs implicated in immune evasion, identification of pattern recognition receptors, regulation of lymphocyte activation and lethality, modulation of infected host cell antigen, maintain of EBV infection status, promotion of cell proliferation, invasion and migration, and reduction of apoptosis. As good news, not only has recent data demonstrated the crucial function of EBV-encoded miRNAs in the pathogenesis of EBVaGC, but it has also been revealed that aberrant expression of exosomal miRNAs in EBVaGC has made them biomarkers for detection of EBVaGC. Regarding these substantial characterizes, the critical role of EBV-encoded miRNAs has been a hot topic in research. In this review, we will focus on the multiple mechanisms involved in EBVaGC caused by EBV-encoded miRNAs and briefly discuss their potential application in the clinic as a diagnostic biomarker.