MIR4435-2HG in exosomes promotes gastric carcinogenesis by inducing M2 polarization in macrophages

The science of exosomes: Understanding their formation, capture, and role in cellular communication

Extracellular vesicles (EVs) serve as a crucial method for transferring information among cells, which is vital in multicellular organisms. Among these vesicles, exosomes are notable for their small size, ranging from 20 to 150 nm, and their role in cell-to-cell communication. They carry lipids, proteins, and nucleic acids between cells. The creation of exosomes begins with the inward budding of the cell membrane, which then encapsulates various macromolecules as cargo. Once filled, exosomes are released into the extracellular space and taken up by target cells via endocytosis and similar processes. The composition of exosomal cargo varies, encompassing diverse macromolecules with specific functions. Because of their significant roles, exosomes have been isolated from various cell types, including cancer cells, endothelial cells, macrophages, and mesenchymal cells, with the aim of harnessing them for therapeutic applications. Exosomes influence cellular metabolism, and regulate lipid, glucose, and glutamine pathways. Their role in pathogenesis is determined by their cargo, which can manipulate processes such as apoptosis, proliferation, inflammation, migration, and other molecular pathways in recipient cells. Non-coding RNA transcripts, a common type of cargo, play a pivotal role in regulating disease progression. Exosomes are implicated in numerous biological and pathological processes, including inflammation, cancer, cardiovascular diseases, diabetes, wound healing, and ischemic-reperfusion injury. As a result, they hold significant potential in the treatment of both cancerous and non-cancerous conditions.

LncRNAs act as modulators of macrophages within the tumor microenvironment

Long non-coding RNAs (lncRNAs) have been established as pivotal players in various cellular processes, encompassing the regulation of transcription, translation and post-translational modulation of proteins, thereby influencing cellular functions. Notably, lncRNAs exert a regulatory influence on diverse biological processes, particularly in the context of tumor development. Tumor-associated macrophages (TAMs) exhibit the M2 phenotype, exerting significant impact on crucial processes such as tumor initiation, angiogenesis, metastasis and immune evasion. Elevated infiltration of TAMs into the tumor microenvironment (TME) is closely associated with a poor prognosis in various cancers. LncRNAs within TAMs play a direct role in regulating cellular processes. Functioning as integral components of tumor-derived exosomes, lncRNAs prompt the M2-like polarization of macrophages. Concurrently, reports indicate that lncRNAs in tumor cells contribute to the expression and release of molecules that modulate TAMs within the TME. These actions of lncRNAs induce the recruitment, infiltration and M2 polarization of TAMs, thereby providing critical support for tumor development. In this review, we survey recent studies elucidating the impact of lncRNAs on macrophage recruitment, polarization and function across different types of cancers.

Extracellular vesicles mediated gastric cancer immune response: tumor cell death or immune escape?

Gastric cancer (GC) is a major global health issue, being the fifth most prevalent cancer and the third highest contributor to cancer-related deaths. Although treatment strategies for GC have diversified, the prognosis for advanced GC remains poor. Hence, there is a critical need to explore new directions for GC treatment to enhance diagnosis, treatment, and patient prognosis. Extracellular vesicles (EVs) have emerged as key players in tumor development and progression. Different sources of EVs carry different molecules, resulting in distinct biological functions. For instance, tumor-derived EVs can promote tumor cell proliferation, alter the tumor microenvironment and immune response, while EVs derived from immune cells carry molecules that regulate immune function and possess tumor-killing capabilities. Numerous studies have demonstrated the crucial role of EVs in the development, immune escape, and immune microenvironment remodeling in GC. In this review, we discuss the role of GC-derived EVs in immune microenvironment remodeling and EVs derived from immune cells in GC development. Furthermore, we provide an overview of the potential uses of EVs in immunotherapy for GC.

The role of the Notch signaling pathway in bacterial infectious diseases

The Notch signaling pathway is the most crucial link in the normal operation and maintenance of physiological functions of mammalian life processes. Notch receptors interact with ligands and this leads to three cleavages and goes on to enter the nucleus to initiate the transcription of target genes. The Notch signaling pathway deeply participates in the differentiation and function of various cells, including immune cells. Recent studies indicate that the outcomes of Notch signaling are changeable and highly dependent on different bacterial infection. The Notch signaling pathway plays a different role in promoting and inhibiting bacterial infection. In this review, we focus on the latest research findings of the Notch signaling pathway in bacterial infectious diseases. The Notch signaling pathway is critically involved in a variety of development processes of immunosuppression of different APCs. The Notch signaling pathway leads to functional changes in epithelial cells to aggravate tissue damage. Specifically, we illustrate the regulatory mechanism of the Notch signaling pathway in various bacterial infections, such as Mycobacterium tuberculosis, Mycobacterium avium paratuberculosis, Mycobacterium leprae, Helicobacter pylori, Klebsiella pneumoniae, Bacillus subtilis, Staphylococcus aureus, Ehrlichia chaffeensis and sepsis. Collectively, this review will not only help beginners intuitively and systematically understand the Notch signaling pathway in bacterial infectious diseases but also help experts to generate fresh insight in this field.

Exosome-mediated communication between gastric cancer cells and macrophages: implications for tumor microenvironment

Gastric cancer (GC) is a malignant neoplasm originating from the epithelial cells of the gastric mucosa. The pathogenesis of GC is intricately linked to the tumor microenvironment within which the cancer cells reside. Tumor-associated macrophages (TAMs) primarily differentiate from peripheral blood monocytes and can be broadly categorized into M1 and M2 subtypes. M2-type TAMs have been shown to promote tumor growth, tissue remodeling, and angiogenesis. Furthermore, they can actively suppress acquired immunity, leading to a poorer prognosis and reduced tolerance to chemotherapy. Exosomes, which contain a myriad of biologically active molecules including lipids, proteins, mRNA, and noncoding RNAs, have emerged as key mediators of communication between tumor cells and TAMs. The exchange of these molecules via exosomes can markedly influence the tumor microenvironment and consequently impact tumor progression. Recent studies have elucidated a correlation between TAMs and various clinicopathological parameters of GC, such as tumor size, differentiation, infiltration depth, lymph node metastasis, and TNM staging, highlighting the pivotal role of TAMs in GC development and metastasis. In this review, we aim to comprehensively examine the bidirectional communication between GC cells and TAMs, the implications of alterations in the tumor microenvironment on immune escape, invasion, and metastasis in GC, targeted therapeutic approaches for GC, and the efficacy of potential GC drug resistance strategies.

The biological role of extracellular vesicles in gastric cancer metastasis

Gastric cancer (GC) is a tumor characterized by high incidence and mortality, with metastasis being the primary cause of poor prognosis. Extracellular vesicles (EVs) are an important intercellular communication medium. They contain bioactive substances such as proteins, nucleic acids, and lipids. EVs play a crucial biological role in the process of GC metastasis. Through mechanisms such as remodeling the tumor microenvironment (TME), immune suppression, promoting angiogenesis, and facilitating epithelial-mesenchymal transition (EMT) and mesothelial-mesenchymal transition (MMT), EVs promote invasion and metastasis in GC. Further exploration of the biological roles of EVs will contribute to our understanding of the mechanisms underlying GC metastasis and may provide novel targets and strategies for the diagnosis and treatment of GC. In this review, we summarize the mechanisms by which EVs influence GC metastasis from four aspects: remodeling the TME, modulating the immune system, influencing angiogenesis, and modulating the processes of EMT and MMT. Finally, we briefly summarized the organotropism of GC metastasis as well as the potential and limitations of EVs in GC.

Biological Roles and Pathogenic Mechanisms of LncRNA MIR4435-2HG in Cancer: A Comprehensive Review

The long non-coding RNA MIR4435-2HG has been confirmed to play a crucial regulatory role in various types of tumors. As a novel type of non-coding RNA, MIR4435-2HG plays a key role in regulating the expression of tumor-related genes, interfering with cellular signaling pathways, and affecting tumor immune evasion. Its unique structure allows it to regulate the expression of various tumor-related genes through different pathways, participating in the regulation of tumor signaling pathways, such as regulating the expression of oncogenes and tumor suppressor genes, influencing the biological behaviors of proliferation, metastasis, and apoptosis in tumors. Numerous studies have found a high expression of MIR4435-2HG in various tumor tissues, closely related to the clinical pathological characteristics of tumors, such as staging, lymph node metastasis and prognosis. Some studies have discovered that MIR4435-2HG can regulate the sensitivity of tumor cells to chemotherapy drugs, affecting tumor cell drug resistance. This provides new insights into overcoming tumor drug resistance by regulating MIR4435-2HG. Therefore, studying its molecular mechanisms, expression regulation, and its relationship with the clinical features of tumors is of great significance for revealing the mechanisms of tumor occurrence and developing new therapeutic targets.

Small extracellular vesicles - A host for advanced bioengineering and "Trojan Horse" of non-coding RNAs

Small extracellular vesicles (sEVs) are a type of membranous vesicles that can be released by cells into the extracellular space. The relationship between sEVs and non-coding RNAs (ncRNAs) is highly intricate and interdependent. This symbiotic relationship plays a pivotal role in facilitating intercellular communication and holds profound implications for a myriad of biological processes. The concept of sEVs and their ncRNA cargo as a "Trojan Horse" highlights their remarkable capacity to traverse biological barriers and surreptitiously deliver their cargo to target cells, evading detection by the host-immune system. Accumulating evidence suggests that sEVs may be harnessed as carriers to ferry therapeutic ncRNAs capable of selectively silencing disease-driving genes, particularly in conditions such as cancer. This approach presents several advantages over conventional drug delivery methods, opening up new possibilities for targeted therapy and improved treatment outcomes. However, the utilization of sEVs and ncRNAs as therapeutic agents raises valid concerns regarding the possibility of unforeseen consequences and unintended impacts that may emerge from their application. It is important to consider the fundamental attributes of sEVs and ncRNAs, including by an in-depth analysis of the practical and clinical potentials of exosomes, serving as a representative model for sEVs encapsulating ncRNAs.

Dynamic relationship between the aryl hydrocarbon receptor and long noncoding RNA balances cellular and toxicological responses

The aryl hydrocarbon receptor (AhR) is a cytosolic transcription factor activated by endogenous ligands and xenobiotic chemicals. Once the AhR is activated, it translocates to the nucleus, dimerizes with the AhR nuclear translator (ARNT) and binds to xenobiotic response elements (XRE) to promote gene transcription, notably the cytochrome P450 CYP1A1. The AhR not only mediates the toxic effects of environmental chemicals, but also has numerous putative physiological functions. This dichotomy in AhR biology may be related to reciprocal regulation of long non-coding RNA (lncRNA). lncRNA are defined as transcripts more than 200 nucleotides in length that do not encode a protein but are implicated in many physiological processes such as cell differentiation, cell proliferation, and apoptosis. lncRNA are also linked to disease pathogenesis, particularly the development of cancer. Recent studies have revealed that AhR activation by environmental chemicals affects the expression and function of lncRNA. In this article, we provide an overview of AhR signaling pathways activated by diverse ligands and highlight key differences in the putative biological versus toxicological response of AhR activation. We also detail the functions of lncRNA and provide current data on their regulation by the AhR. Finally, we outline how overlap in function between AhR and lncRNA may be one way in which AhR can be both a regulator of endogenous functions but also a mediator of toxicological responses to environmental chemicals. Overall, more research is still needed to fully understand the dynamic interplay between the AhR and lncRNA.

Tumour-associated macrophages in gastric cancer: From function and mechanism to application

BACKGROUND

Gastric cancer (GC) is a malignant tumour, with high morbidity and mortality rates worldwide. The occurrence and development of GC is a complex process involving genetic changes in tumour cells and the influence of the surrounding tumour microenvironment (TME). Accumulative evidence shows that tumour-associated macrophages (TAMs) play a vital role in GC, acting as plentiful and active infiltrating inflammatory cells in the TME.

MAIN BODY

In this review, the different functions and mechanisms of TAMs in GC progression, including the conversion of phenotypic subtypes; promotion of tumour proliferation, invasion and migration; induction of chemoresistance; promotion of angiogenesis; modulation of immunosuppression; reprogramming of metabolism; and interaction with the microbial community are summarised. Although the role of TAMs in GC remains controversial in clinical settings, clarifying their significance in the treatment selection and prognostic prediction of GC could support optimising TAM-centred clinicaltherapy.

CONCLUSION

In summary, we reviewed the the phenotypic polarisation, function and molecular mechanism of TAMs and their potential applications in the treatment selection and prognostic prediction of GC.