Gastric Cancer in the Era of Epigenetics

Nicotinamide N-methyltransferase as a potential therapeutic target for neurodegenerative disorders: Mechanisms, challenges, and future directions

Neurodegenerative diseases (NDs), including Alzheimer's disease (AD), Parkinson's disease (PD), and Huntington's disease (HD), are characterized by progressive neuronal loss and functional decline, posing significant global health challenges. Emerging evidence highlights nicotinamide N-methyltransferase (NNMT), a cytosolic enzyme regulating nicotinamide (NAM) methylation, as a pivotal player in NDs through its dual impact on epigenetic regulation and metabolic homeostasis. This review synthesizes current knowledge on NNMT's role in disease pathogenesis, focusing on its epigenetic modulation via DNA hypomethylation and histone modifications, alongside its disruption of NAD+ synthesis and homocysteine (Hcy) metabolism. Elevated NNMT activity depletes NAD+, exacerbating mitochondrial dysfunction and impairing energy metabolism, while increased Hcy levels drive oxidative stress, neuroinflammation, and aberrant protein aggregation (e.g., Aβ, tau, α-synuclein). Notably, NNMT overexpression in AD and PD correlates with neuronal hypomethylation and neurotoxicity, as observed in postmortem brain studies and transgenic models. Mechanistically, NNMT consumes S-adenosylmethionine (SAM), limiting methyl donor availability for DNA methyltransferases (DNMTs) and histone methyltransferases (HMTs), thereby altering gene expression patterns critical for neuronal survival. Concurrently, NNMT-mediated NAD+ depletion disrupts sirtuin activity (e.g., SIRT1) and mitochondrial biogenesis, accelerating axonal degeneration. Therapeutic strategies targeting NNMT, such as RNA interference (RNAi), small-molecule inhibitors and exercise therapy, show promise in preclinical models by restoring NAD+ levels and reducing Hcy toxicity. However, challenges persist in achieving cellular specificity, optimizing blood-brain barrier penetration, and mitigating off-target effects. This review underscores NNMT's potential as a multifactorial therapeutic target, bridging metabolic and epigenetic dysregulation in NDs. Future research should prioritize elucidating tissue-specific NNMT interactions, refining inhibitor pharmacokinetics, and validating translational efficacy in clinical trials. Addressing these gaps could pave the way for novel disease-modifying therapies to combat the rising burden of neurodegeneration.

MiR-3613-5p targets AQP4 to promote the progression of chronic atrophic gastritis to gastric cancer

Introduction: Gastric cancer (GC) exhibits high invasiveness, delayed diagnosis, and poor prognosis. Chronic atrophic gastritis (CAG), an initial stage within the Correa cascade, induces gastric mucosal inflammation and atrophy, promoting genetic and epigenetic alterations. MicroRNAs (miRNAs) dysregulation has been implicated in gastric tumorigenesis, yet their specific roles in CAG progression to GC remain unclear. Methods: Using clinical data from the GEO database, we identified miRNAs differentially expressed in gastric mucosa and serum samples from GC patients. Murine CAG models were established through administration of N-methyl-N-nitrosourea (MNU) and high-salt diet (HSD). In vitro functional assays evaluated proliferation and migration after miRNA modulation in gastric cancer cell lines. MiRNA target validation involved luciferase reporter assays. Results: MiR-3613-5p expression was significantly elevated in gastric mucosal and serum samples of GC patients, mucosal tissues of CAG patients, tumor tissues, and human gastric cancer cell lines. Murine models demonstrated increased miR-3613-5p expression in gastric mucosa following MNU and HSD-induced CAG. Functionally, miR-3613-5p overexpression promoted gastric cancer cell proliferation and migration in vitro, whereas silencing miR-3613-5p alleviated pathological gastric mucosal alterations (atrophy, hyperplasia, inflammatory infiltration) in vivo. Mechanistically, miR-3613-5p inhibited Aquaporin 4 (AQP4) expression by directly targeting its 3'UTR. Discussion: Our findings provide the first evidence that miR-3613-5p facilitates CAG progression toward GC via negative regulation of AQP4. These results highlight miR-3613-5p as a promising biomarker and therapeutic target, suggesting antagomiR-3613-5p as a potential novel strategy to prevent gastric carcinogenesis.

Noncoding RNA (ncRNA)-mediated regulation of TLRs: critical regulator of inflammation in tumor microenvironment

Toll-like receptors (TLRs) are central components of the innate immune system as they recognize molecular patterns associated with pathogens and cellular damage and initiate immune responses using MyD88- and TRIF-dependent pathways. In contrast to being very useful for immune defense, dysregulated TLR signaling may be involved in diseases, such as cancer and autoimmune conditions. In cancer, TLRs create an environment that supports tumorigenesis and growth. In addition to this, a class of multifunctional noncoding RNAs (ncRNAs), including miRNAs, lncRNAs, and circRNAs, regulate gene expression without encoding proteins. MiRNAs regulate gene expression in a fine-tuned manner, while lncRNAs and circRNAs do so via diverse mechanisms. Notably, these ncRNAs interact, where lncRNAs and circRNAs function as competing endogenous RNAs and ceRNA, affecting miRNA activity. This interaction has a vital role in cancer pathology, in influencing that of various oncogenes and tumor suppressors in the tumor microenvironment; hence, modulation of ncRNAs could also be a great promising therapeutic approach. In this context, interplay between TLRs and ncRNAs is of paramount importance as they influence various parameters of the tumor microenvironment. TLR signaling works upon the expression of ncRNAs, while ncRNAs work back to regulate TLR signaling in return. An example of this includes miRNA targeting of components of the TLR; lncRNAs induced by TLR signaling possibly would favor tumor progression. Pharmacological interventions directed toward inhibiting these TLR pathways could be the model to halt malignancy by hampering pro-tumor inflammation and boosting immune responses against neoplasms. Hence, the review will highlight the complicated contrast of ncRNAs and TLRs within human cancer. By connecting the mechanisms, the researchers may study more about tumorigenesis and gather up new, innovative notions regarding therapeutic targeting.

MAZ-mediated LAMA5 transcription activation promotes gastric cancer progression through the STAT3 signaling

Laminin subunit alpha-5 (LAMA5) has been identified as an oncogene in many cancers, while its role and mechanism in gastric cancer (GC) remain to be explored. Here, the influences of LAMA5 knockdown on GC were investigated in vitro and in vivo. LAMA5 expression was silenced in GC cells alone or in combination with the signal transducer and activator of transcription 3 (STAT3) activator Colivelin, followed by CCK-8, colony formation, EdU, flow cytometry, wound healing assay, and Transwell assay. The regulatory relationship between Myc-associated zinc finger protein (MAZ) and LAMA5 was characterized by ChIP and luciferase reporter analysis. The effect of knockdown of MAZ alone or in combination with LAMA5 overexpression on GC was investigated in vitro and in vivo. LAMA5 was highly expressed in GC cells, and knockdown of LAMA5 inhibited GC cell malignant aggressiveness, which was reversed by the Colivelin treatment. The transcription factor MAZ bound to the promoter of LAMA5 to activate its transcription, and the anti-tumor effects of sh-MAZ on GC cells in vitro and in vivo were overturned by LAMA5 overexpression. In conclusion, MAZ promotes GC cell proliferation and migration by the LAMA5/STAT3 axis, implying that this axis can function as a target for GC therapy.

Identifying the function of kinesin superfamily proteins in gastric cancer: Implications for signal transduction, clinical significance, and potential therapeutic approaches

Gastric cancer (GC), a leading cause of cancer-related mortality, poses a significant global health challenge. Given its complex etiology, understanding the molecular pathways driving GC progression is crucial for developing innovative therapeutic strategies. Among the diverse proteins involved in cellular transport and mitotic regulation, kinesin superfamily proteins (KIFs) have emerged as key players in tumor biology. These motor proteins mediate intracellular transport along microtubules and are essential for processes such as cell division, signaling, and organelle distribution. Evidence indicates that specific KIFs are dysregulated in GC, potentially driving cancer cell proliferation, metastasis, and chemoresistance. Moreover, aberrant KIF expression has been associated with poorer prognoses, highlighting their potential as biomarkers for early diagnosis and therapeutic intervention. This review explores the roles of KIFs in GC and assesses their implications for research and clinical applications. By elucidating the significance of KIFs in GC, this discussion aims to inspire novel insights in cancer biology and advance targeted therapeutic strategies.

Nanomaterials in gastric cancer: pioneering precision medicine for diagnosis, therapy, and prevention

Gastric cancer (GC) continues to be a major health issue globally due to its high rates of both occurrence and mortality. Despite advancements in treatment, the outlook for those affected remains poor, highlighting the critical need for new diagnostic and treatment methods. Nanotechnology, especially nanoparticles, is emerging as a crucial innovation in cancer care by improving imaging, targeting drug delivery, and enhancing early detection. These nanoparticles are also enhancing the effectiveness of treatments like phototherapy, chemotherapy, and immunotherapy. Notably, they show potential in addressing infections like Helicobacter pylori (H. pylori), which is known to increase the risk of developing GC. This review underscores the pivotal role of nanotechnology in enhancing the integrated management of GC, offering a basis for future advancements in the field.

Association of Helicobacter pylori related chronic atrophic gastritis and gastric cancer risk: a literature review

Chronic atrophic gastritis (CAG) is considered to be closely related to Helicobacter pylori (H. pylori) infection and characterized by the atrophy and/or intestinal metaplasia (IM) of the gastric mucosa in pathology. CAG is often regarded as the precancerous lesion of gastric cancer and H. pylori infection stimulates the development of atrophy and IM and the progression of gastric cancer through the persistent effect acting on the gastric mucosa, including releasing inflammatory factors such as Interleukin-8(IL-8). From the molecular biology perspective, growing evidence shows that H. pylori probably induce the expression of NF-κB, miR-204, miR-27a, hnRNPA2B1, and JARID1B, which play crucial roles in the progression of CAG into gastric cancer. In addition, H. pylori can increase Epstein-Barr virus (EBV) infection, and the co-infection will jointly increase gastric cancer risk. Furthermore, H. pylori induces cellular senescence and promotes atrophy progression and finally increases the gastric cancer risk. This review aims to explore the carcinogenic mechanisms of H. pylori related CAG in order to provide theoretical foundations for the pathogenesis mechanism and early detection and prevention of gastric cancer.

METTL3 stabilizes SERPINE2 via the m6A modification to drive the malignant progression of gastric signet ring cell carcinoma

Background

Gastric signet ring cell carcinoma (GSRCC) is a highly lethal malignancy. Serpin family E member 2 (SERPINE2) is a pro-tumorigenic factor in cancer. Here, we sought to define the role of SERPINE2 in the pathogenesis of GSRCC.

Methods

Messenger RNA (mRNA) expression was analyzed by quantitative polymerase chain reaction (PCR). Protein expression was tested by immunohistochemistry (IHC) and immunoblot assays. Proliferation was assessed by 5-ethynyl-2'-deoxyuridine (EdU) assay, and invasion and migration were detected by transwell assay. Tube formation assay was used to test the influence on angiogenesis. Cell apoptosis and M2 macrophage polarization were evaluated by flow cytometry. The methyltransferase-like 3 (METTL3)-SERPINE2 relationship was analyzed by RNA immunoprecipitation (RIP), luciferase, and mRNA stabilization assays. Xenograft experiments were used for assessment of METTL3's influence on tumorigenicity of GSRCC cells.

Results

SERPINE2 and METTL3 levels were upregulated in human GSRCC. Functionally, SERPINE2 depletion enhanced apoptosis of GSRCC cells and diminished their proliferative, migratory and invasive capacities in vitro. Moreover, SERPINE2 depletion suppressed tube formation ability of human umbilical vein endothelial cells (HUVECs) and M2 polarization of THP-1-derived macrophages. Mechanistically, METTL3 induced SERPINE2 upregulation by enhancing SERPINE2 mRNA stabilization. Our rescue experiments indicated that the effects of METTL3 depletion on cell phenotypes were due to the reduction of SERPINE2 expression. Additionally, METTL3 deficiency inhibited GSRCC xenograft growth in vivo.

Conclusions

Our study defines the significant roles of the METTL3/SERPINE2 axis as an epigenetic mechanism in GSRCC progression. Our work may have diagnostic and/or therapeutic applications in GSRCC.

Vorinostat Treatment of Gastric Cancer Cells Leads to ROS-Induced Cell Inhibition and a Complex Pattern of Molecular Alterations in Nrf2-Dependent Genes

Histone deacetylase inhibitors (HDACi) show high antineoplastic potential in preclinical studies in various solid tumors, including gastric carcinoma; however, their use in clinical studies has not yet yielded convincing efficacies. Thus, further studies on cellular/molecular effects of HDACi are needed, for improving clinical efficacy and identifying suitable combination partners. Here, we investigated the role of oxidative stress in gastric cancer cells upon treatment with HDACi. A particular focus was laid on the role of the Nrf2 pathway, which can mediate resistance to cell-inhibitory effects of reactive oxidative species (ROS). Using fluorescence-based ROS sensors, oxidative stress was measured in human gastric cancer cell lines. Activation of the Nrf2 pathway was monitored in luciferase reporter assays as well as by mRNA and proteomic expression analyses of Nrf2 regulators and Nrf2-induced genes. Furthermore, the effects of ROS scavenger N-acetyl-L-cysteine (NAC) and Nrf2-knockdown on HDACi-dependent antiproliferative effects were investigated in colorimetric formazan-based and clonogenic survival assays. HDACi treatment led to increased oxidative stress levels and consequently, treatment with NAC reduced cytotoxicity of HDACi. In addition, vorinostat treatment stimulated expression of a luciferase reporter under the control of an antioxidative response element, indicating activation of the Nrf2 system. This Nrf2 activation was only partially reversible by treatment with NAC, suggesting ROS independent pathways to contribute to HDACi-promoted Nrf2 activation. In line with its cytoprotective role, Nrf2 knockdown led to a sensitization against HDACi. Accordingly, the expression of antioxidant and detoxifying Nrf2 target genes was upregulated upon HDACi treatment. In conclusion, oxidative stress induction upon HDAC inhibition contributes to the antitumor effects of HDAC inhibitors, and activation of Nrf2 represents a potentially important adaptive response of gastric cancer cells in this context.

Interaction of ncRNAs and the PI3K/AKT/mTOR pathway: Implications for osteosarcoma

Osteosarcoma (OS) is the most common primary malignant bone tumor in children and adolescents, and is characterized by high heterogeneity, high malignancy, easy metastasis, and poor prognosis. Recurrence, metastasis, and multidrug resistance are the main problems that limit the therapeutic effect and prognosis of OS. PI3K/AKT/mTOR signaling pathway is often abnormally activated in OS tissues and cells, which promotes the rapid development, metastasis, and drug sensitivity of OS. Emerging evidence has revealed new insights into tumorigenesis through the interaction between the PI3K/AKT/mTOR pathway and non-coding RNAs (ncRNAs). Therefore, we reviewed the interactions between the PI3K/AKT/mTOR pathway and ncRNAs and their implication in OS. These interactions have the potential to serve as cancer biomarkers and therapeutic targets in clinical applications.

Non-Invasive Markers for the Detection of Gastric Precancerous Conditions

Gastric cancer (GC) is still one of the most prevalent cancers worldwide, with a high mortality rate, despite improvements in diagnostic and therapeutic strategies. To diminish the GC burden, a modification of the current diagnostic paradigm, and especially endoscopic diagnosis of symptomatic individuals, is necessary. In this review article, we present a broad review and the current knowledge status on serum biomarkers, including pepsinogens, gastrin, Gastropanel®, autoantibodies, and novel biomarkers, allowing us to estimate the risk of gastric precancerous conditions (GPC)-atrophic gastritis and gastric intestinal metaplasia. The aim of the article is to emphasize the role of non-invasive testing in GC prevention. This comprehensive review describes the pathophysiological background of investigated biomarkers, their status and performance based on available data, as well as their clinical applicability. We point out future perspectives of non-invasive testing and possible new biomarkers opportunities.