Combination of Four Serum Exosomal MiRNAs as Novel Diagnostic Biomarkers for Early-Stage Gastric Cancer

The potential of exosomes in regenerative medicine and in the diagnosis and therapies of neurodegenerative diseases and cancer

Exosomes, nanosized extracellular vesicles released by various cell types, are intensively studied for the diagnosis and treatment of cancer and neurodegenerative diseases, and they also display high usability in regenerative medicine. Emphasizing their diagnostic potential, exosomes serve as carriers of disease-specific biomarkers, enabling non-invasive early detection and personalized medicine. The cargo loading of exosomes with therapeutic agents presents an innovative strategy for targeted drug delivery, minimizing off-target effects and optimizing therapeutic interventions. In regenerative medicine, exosomes play a crucial role in intercellular communication, facilitating tissue regeneration through the transmission of bioactive molecules. While acknowledging existing challenges in standardization and scalability, ongoing research efforts aim to refine methodologies and address regulatory considerations. In summary, this review underscores the transformative potential of exosomes in reshaping the landscape of medical interventions, with a particular emphasis on cancer, neurodegenerative diseases, and regenerative medicine.

Role of exosomal miRNAs and macrophage polarization in gastric cancer: A novel therapeutic strategy

Gastric cancer (GC) is one of the most common gastrointestinal cancers worldwide, with consistently high morbidity and mortality rates and poor prognosis. Most patients are diagnosed at an advanced stage due to the lack of specific presentation in the early stages. Exosomes are a class of extracellular vesicles (EVs) widely found in body fluids and can release genetic material or multiple proteins to facilitate intercellular communication. In recent years, exosomal miRNAs have gained attention for their role in various cancers. These exosomal miRNAs can impact GC development and progression by targeting specific genes or influencing signaling pathways and cytokines involved in Angiogenesis, epithelial-mesenchymal transition (EMT), drug resistance, and immune regulation. They show great potential in terms of diagnosis, prognosis, and treatment of GC. Notably, the gastrointestinal tract has the largest number of macrophages, which play a significant role in GC progression. Tumor-associated macrophages (TAMs) are the most abundant immune cells in the tumor microenvironment (TME) and can influence macrophage programming through various mediators, including macrophage polarization. Macrophage polarization is involved in inflammatory responses and significantly impacts the GC process.

Diagnostic Value of Glycosylated Extracellular Vesicle microRNAs in Gastric Cancer

Introduction

Early diagnosis is crucial for improving the prognosis of patients with gastric cancer (GC). However, the currently used biomarkers for diagnosing GC have limited sensitivity and specificity. This study aimed to develop a novel diagnostic model based on miRNAs from glycosylated extracellular vesicles and evaluate its effectiveness in diagnosing gastric cancer.

Methods

GlyExo-capture technology was used to isolate glycosylated extracellular vesicles from serum samples. The signatures were screened in a discovery cohort of GC patients (n=55) and non-disease controls (n=46) using an integrated process, including high-throughput sequencing technology, screening using a complete bioinformatics algorithm, validation using RT-qPCR, and evaluation by constructing a diagnostic model. The diagnostic model was evaluated in an independent validation cohort (n=139).

Results

We developed a diagnostic model for GC based on five miRNA pairs. This diagnostic model demonstrated high sensitivity, specificity, and stable performance in distinguishing GC patients from non-cancer controls with AUC of 0.930 in the independent validation cohort, particularly in differentiating early-stage GC from benign patients. The markers also showed excellent performance in indicating perineural invasion status and lymph node metastasis in the testing cohort.

Discussion

The model demonstrated high sensitivity and specificity in diagnosing patients with GC, especially in differentiating early-stage GC from benign patients. The five miRNA pairs could also aid in making treatment decisions. Thus, miRNAs derived from glycosylated exosomes are promising biomarkers for cancer diagnosis.

Diagnostic and Prognostic Significance of Exosomes and Their Components in Patients With Cancers

BACKGROUND

Cancer is the second leading cause of human mortality worldwide. Extracellular vesicles (EVs) from liquid biopsy samples are used in early cancer detection, characterization, and surveillance. Exosomes are a subset of EVs produced by all cells and present in all body fluids. They play an important role in the development of cancer because they are active transporters capable of carrying the contents of any type of cell. The objective of this review was to provide a brief overview of the clinical implication of exosomes or exosomal components in cancer diagnosis and prognosis.

METHODS

An extensive review of the current literature of exosomes and their components in cancer diagnosis and prognosis were carried out in the current study.

RESULTS

Tumor cells release exosomes that contribute to the formation of the pre-metastatic microenvironment, angiogenesis, invasion, and treatment resistance. On the contrary, tumor cells release more exosomes than normal cells, and these tumor-specific exosomes can carry the genomic and proteomic signature contents of the tumor cells, which can act as tools for the diagnosis and prognosis of patients with cancers.

CONCLUSION

This information may help clinicians to improve the management of cancer patients in clinical settings in the future.

Extracellular vesicles derived from melanoma cells induce carcinoma-associated fibroblasts via miR-92b-3p mediated downregulation of PTEN

In melanoma, carcinoma-associated fibroblasts (CAFs) are important cellular components in the tumour microenvironment due to their potential to promote tumour growth and metastatic spread of malignant cells. Melanoma cells have the ability to affect non-tumour cells in the microenvironment by releasing extracellular vesicles (EVs). The mechanisms responsible for reprogramming normal dermal fibroblasts (NHDFs) into CAFs remain incompletely understood. However, it is likely thought to be mediated by melanoma-specific miRNAs, which are transported by EVs derived from melanoma cells. Therefore, we wondered if one of the most enriched miRNAs in EVs secreted by melanoma cells, miR-92b-3p, is involved in the conversion of normal fibroblasts into CAFs. We observed that melanoma cell-derived EVs indeed delivered miR-92b-3p into NHDFs and that its accumulation correlated with CAF formation, as demonstrated by enhanced expression of CAF marker genes and increased proliferation and migration. Overexpression of miR-92b-3p in NHDFs revealed similar results, while EVs deficient of miR-92b-3p did not induce a CAF phenotype. As a target we identified PTEN, whose repression led to increased expression of CAF markers. We thus provide a novel pathway of intercellular communication by which melanoma cells control the transformation of CAFs by virtue of EV-transported miRNAs.

Serum extracellular vesicle-derived miR-21-5p and miR-26a-5p as non-invasive diagnostic potential biomarkers for gastric cancer: A preliminary study

PURPOSE

Gastric cancer is the most common malignancy worldwide and is the third leading cause of cancer-related deaths, urgently requiring an early and non-invasive diagnosis. Circulating extracellular vesicles may emerge as promising biomarkers for the rapid diagnosis in a non-invasive manner.

METHODS

Using high-throughput small RNA sequencing, we profiled the small RNA population of serum-derived extracellular vesicles from healthy controls and gastric cancer patients. Differentially expressed microRNAs (miRNAs) were randomly selected and validated by reverse transcription-quantitative real-time polymerase chain reaction. Receiver operating characteristic curves were employed to assess the predictive value of miRNAs for gastric cancer.

RESULTS

In this study, 193 differentially expressed miRNAs were identified, of which 152 were upregulated and 41 were significantly downregulated. Among the differently expressed miRNA, the expression levels of miR-21-5p, miR-26a-5p, and miR-27a-3p were significantly elevated in serum-derived extracellular vesicles of gastric cancer patients. The miR-21-5p and miR-27a-3p were closely correlated with the tumor size. Moreover, the expression levels of serum miR-21-5p and miR-26a-5p were significantly decreased in gastric cancer patients after surgery.

CONCLUSIONS

The present study discovered the potential of serum miR-21-5p and miR-26a-5p as promising candidates for the diagnostic and prognostic markers of gastric cancer.

Extracellular Vesicle miRNAs in Diagnostics of Gastric Cancer

Gastric cancer (GC) poses a significant global health challenge because of its high mortality rate attributed to the late-stage diagnosis and lack of early symptoms. Early cancer diagnostics is crucial for improving the survival rates in GC patients, which emphasizes the importance of identifying GC markers for liquid biopsy. The review discusses a potential use of extracellular vesicle microRNAs (EV miRNAs) as biomarkers for the diagnostics and prognostics of GC. Methods. Original articles on the identification of EV miRNA as GC markers published in the Web of Science and Scopus indexed issues were selected from the PubMed and Google Scholar databases. We focused on the methodological aspects of EV analysis, including the choice of body fluid, methods for EV isolation and validation, and approaches for EV miRNA analysis. Conclusions. Out of 33 found articles, the majority of authors investigated blood-derived extracellular vesicles (EVs); only a few utilized EVs from other body fluids, including tissue-specific local biofluids (washing the tumor growth areas), which may be a promising source of EVs in the context of cancer diagnostics. GC-associated miRNAs identified in different studies using different methods of EV isolation and analysis varied considerably. However, three miRNAs (miR-10b, miR-21, and miR-92a) have been found in several independent studies and shown to be associated with GC in experimental models. Further studies are needed to determine the optimal miRNA marker panel. Another essential step necessary to improve the reliability and reproducibility of EV-based diagnostics is standardization of methodologies for EV handling and analysis of EV miRNA.

Circulating miRNA and circulating tumor DNA application as liquid biopsy markers in gastric cancer

Liquid biopsy has been investigated as a novel method to overcome the numerous challenges in gastric cancer (GC) management. This non-invasive, feasible, and easy-to-repeat method has been shown to be cost-effective and capable of increasing diagnostic sensitivity and prognostic assessment. Additionally, it is potentially accurate to aid decision-making and personalized treatment planning. MicroRNA (miRNA) and circulating tumor DNA (ctDNA) markers can enhance GC management in various aspects, including diagnosis (mainly earlier diagnosis and the ability to perform population-based screening), prognosis (more precise stratification of prognosis), and treatment (including more accurate prediction of treatment response and earlier detection of resistance to the treatment). Concerning the treatment-related application, miRNAs' mimics and antagonists (by using two main strategies of restoring tumor suppressor miRNAs and inhibiting oncogene miRNAs) have been shown to be effective therapeutic agents. However, these need to be further validated in clinical trials. Furthermore, novel delivery systems, such as lipid-based vectors, polymeric-based vectors, and exosome-based delivery, have been developed to enhance the performance of these agents. Moreover, this paper explores the current detection and measuring methods for these markers. These approaches are categorized into direct methods (e.g., Chem-NAT, HTG EdgeSeq, and Multiplex Circulating Fireplex) and indirect methods (e.g., Reverse transcription-quantitative polymerase chain reaction (RT-qPCR), qPCR, microarray, and NGS) for miRNA detection. For ctDNA measurement, main core technologies like NGS, digital PCR, real-time PCR, and mass spectrometry are suggested.

Hotspots and trends of risk factors in gastric cancer: A visualization and bibliometric analysis

BACKGROUND

The lack of specific symptoms of gastric cancer (GC) causes great challenges in its early diagnosis. Thus it is essential to identify the risk factors for early diagnosis and treatment of GC and to improve the survival rates.

AIM

To assist physicians in identifying changes in the output of publications and research hotspots related to risk factors for GC, constructing a list of key risk factors, and providing a reference for early identification of patients at high risk for GC.

METHODS

Research articles on risk factors for GC were searched in the Web of Science core collection, and relevant information was extracted after screening. The literature was analyzed using Microsoft Excel 2019, CiteSpace V, and VOSviewer 1.6.18.

RESULTS

A total of 2514 papers from 72 countries and 2507 research institutions were retrieved. China (n = 1061), National Cancer Center (n = 138), and Shoichiro Tsugane (n = 36) were the most productive country, institution, or author, respectively. The research hotspots in the study of risk factors for GC are summarized in four areas, namely: Helicobacter pylori (H. pylori) infection, single nucleotide polymorphism, bio-diagnostic markers, and GC risk prediction models.

CONCLUSION

In this study, we found that H. pylori infection is the most significant risk factor for GC; single-nucleotide polymorphism (SNP) is the most dominant genetic factor for GC; bio-diagnostic markers are the most promising diagnostic modality for GC. GC risk prediction models are the latest current research hotspot. We conclude that the most important risk factors for the development of GC are H. pylori infection, SNP, smoking, diet, and alcohol.

Exosomes: a promising avenue for cancer diagnosis beyond treatment

Exosomes, extracellular vesicles secreted by cells, have garnered significant attention in recent years for their remarkable therapeutic potential. These nanoscale carriers can be harnessed for the targeted delivery of therapeutic agents, such as pharmaceuticals, proteins, and nucleic acids, across biological barriers. This versatile attribute of exosomes is a promising modality for precision medicine applications, notably in the realm of cancer therapy. However, despite their substantial therapeutic potential, exosomes still confront challenges tied to standardization and scalability that impede their practice in clinical applications. Moreover, heterogeneity in isolation methodologies and limited cargo loading mechanisms pose obstacles to ensuring consistent outcomes, thereby constraining their therapeutic utility. In contrast, exosomes exhibit a distinct advantage in cancer diagnosis, as they harbor specific signatures reflective of the tumor's genetic and proteomic profile. This characteristic endows them with the potential to serve as valuable liquid biopsies for non-invasive and real-time monitoring, making possible early cancer detection for the development of personalized treatment strategies. In this review, we provide an extensive evaluation of the advancements in exosome research, critically examining their advantages and limitations in the context of cancer therapy and early diagnosis. Furthermore, we present a curated overview of the most recent technological innovations utilizing exosomes, with a focus on enhancing the efficacy of early cancer detection.

Liquid Biopsy: An Emerging Diagnostic, Prognostic, and Predictive Tool in Gastric Cancer

Liquid biopsy, a minimally invasive procedure that causes minimal pain and complication risks to patients, has been extensively studied for cancer diagnosis and treatment. Moreover, it facilitates comprehensive quantification and serial assessment of the whole-body tumor burden. Several biosources obtained through liquid biopsy have been studied as important biomarkers for establishing early diagnosis, monitoring minimal residual disease, and predicting the prognosis and response to treatment in patients with cancer. Although the clinical application of liquid biopsy in gastric cancer is not as robust as that in other cancers, biomarker studies using liquid biopsy are being actively conducted in patients with gastric cancer. Herein, we aimed to review the role of various biosources that can be obtained from patients with gastric cancer through liquid biopsies, such as blood, saliva, gastric juice, urine, stool, peritoneal lavage fluid, and ascites, by dividing them into cellular and acellular components. In addition, we reviewed previous studies on the diagnostic, prognostic, and predictive biomarkers for gastric cancer using liquid biopsy and discussed the limitations of liquid biopsy and the challenges to overcome these limitations in patients with gastric cancer.

microRNA-92b-3p augments colon cancer development through inhibiting KLF3

Colon cancer (CC) is a tumor of the large intestine. miR-92b-3p is often deregulated in the tumorigensis. Here, the role of miR-92b-3p in the development of CC was investigated. miR-92b-3p and Kruppel-like factor 3 (KLF3) expression was examined in CC tissues and cells. miR-92b-3p inhibitor or KLF3 overexpression vector was transfected into CC cells, respectively to observe its role in CC cell proliferation, invasion, migration, and apoptosis. The targeting relationship between miR-92b-3p and KLF3 was validated. Meanwhile, rescue experiments were performed by co-transfection of miR-92b-3p inhibitor and KLF3 siRNA, followed by determining CC cell proliferation, invasion, migration, and apoptosis. Higher miR-92b-3p and lower KLF3 expression levels were observed in CC tissues and cells. miR-92b-3p inhibition or KLF3 overexpression reduced proliferation, invasion, and migration whereas induced apoptosis of CC cells. KLF3 was validated to be the target gene of miR-92b-3p. Depletion of KLF3 could reverse the antitumor role of miR-92b-3p inhibition in CC cells. miR-92b-3p augments CC development through inhibiting KLF3, which may confers a novel way to develop future treatment target.

Extracellular vesicle biomarkers in circulation for the diagnosis of gastric cancer: A systematic review and meta‑analysis

The prognosis of a gastric cancer (GC) diagnosis is poor due to the current lack of effective early diagnostic methods. Extracellular vesicle (EV) biomarkers have previously demonstrated strong diagnostic efficiency for certain types of cancer, including pancreatic and lung cancer. The present review aimed to summarize the diagnostic value of circulating EV biomarkers for early stage GC. The PubMed, Medline and Web of Science databases were searched from May 1983 to September 18, 2022. All studies that reported the diagnostic performance of EV biomarkers for GC were included for analysis. Overall, 27 studies were selected containing 2,831 patients with GC and 2,117 controls. A total of 58 EV RNAs were reported in 26 studies, including 39 microRNAs (miRNAs), 10 long non-coding RNAs (lncRNAs), five circular RNAs, three PIWI-interacting RNAs and one mRNA, in addition to one protein in the remaining study. Meta-analysis of the aforementioned studies demonstrated that the pooled sensitivity, specificity and AUC value of the total RNAs were 84, 67% and 0.822, respectively. The diagnostic values of miRNAs were consistent with the total RNA, as the pooled sensitivity, specificity and AUC value were 84, 67% and 0.808, respectively. The pooled sensitivity, specificity and AUC values of lncRNAs were 89, 69% and 0.872, respectively, markedly higher compared with that of miRNAs. A total of five studies reported the diagnostic performance of EV RNA panels for early stage GC and reported powerful diagnostic values with a pooled sensitivity, specificity and AUC value of 80, 77% and 0.879, respectively. Circulating EV RNAs could have the potential to be used in the future as effective, noninvasive biomarkers for early GC diagnosis. Further research in this field is necessary to translate these findings into clinical practice.

Emerging role of exosome-shuttled noncoding RNAs in gastrointestinal cancers: From intercellular crosstalk to clinical utility

Gastrointestinal cancer remains a significant global health burden. The pursuit of advancing the comprehension of tumorigenesis, along with the identification of reliable biomarkers and the development of precise therapeutic strategies, represents imperative objectives in this field. Exosomes, small membranous vesicles released by most cells, commonly carry functional biomolecules, including noncoding RNAs (ncRNAs), which are specifically sorted and encapsulated by exosomes. Exosome-mediated communication involves the release of exosomes from tumor or stromal cells and the uptake by nearby or remote recipient cells. The bioactive cargoes contained within these exosomes exert profound effects on the recipient cells, resulting in significant modifications in the tumor microenvironment (TME) and distinct alterations in gastrointestinal tumor behaviors. Due to the feasibility of isolating exosomes from various bodily fluids, exosomal ncRNAs have shown great potential as liquid biopsy-based indicators for different gastrointestinal cancers, using blood, ascites, saliva, or bile samples. Moreover, exosomes are increasingly recognized as natural delivery vehicles for ncRNA-based therapeutic interventions. In this review, we elucidate the processes of ncRNA-enriched exosome biogenesis and uptake, examine the regulatory and functional roles of exosomal ncRNA-mediated intercellular crosstalk in gastrointestinal TME and tumor behaviors, and explore their potential clinical utility in diagnostics, prognostics, and therapeutics.

Four differentially expressed exosomal miRNAs as prognostic biomarkers and therapy targets in endometrial cancer: Bioinformatic analysis

Endometrial cancer (EC) is one of the most common gynecological malignancies worldwide. Accumulated evidence has demonstrated exosomes of cancer cells carry microRNAs (miRNAs) to nonmalignant cells to induce metastasis. Our study aimed to find possible biomarkers of EC. Data for miRNA expression related with exosome from EC patients were downloaded from The Cancer Genome Atlas database, and the miRNA expression profiles associated with exosomes of EC were downloaded from the National Center for Biotechnology Information. We used different algorithms to analyze the differential miRNA expression, infer the relative proportion of immune infiltrating cells, predict chemotherapy sensitivity, and comprehensively score each gene set to evaluate the potential biological function changes of different samples. The gene ontology analysis and Kyoto encyclopedia of genome genomics pathway analysis were performed for specific genes. A total of 13 differential miRNAs were identified, of which 4 were up-regulated. The 4 miRNAs, that is hsa-miR-17-3p, hsa-miR-99b-3p, hsa-miR-193a-5p, and hsa-miR-320d, were the hub exosomal miRNAs that were all closely related to the clinic phenotypes and prognosis of patients. This study preliminarily indicates that the 4 hub exosomal miRNAs (hsa-miR-17-3p, hsa-miR-99b-3p, hsa-miR-193a-5p, and hsa-miR-320d) could be used as prognostic biomarkers or therapy targets in EC. Further studies are required to make sure of their real feasibility and values in the EC clinic and the relative research.

A tale of exosomes and their implication in cancer

Cancer is a cause of high deaths worldwide and also a huge burden for the health system. Cancer cells have unique properties such as a high rate of proliferation, self-renewal, metastasis, and treatment resistance, therefore, the development of novel diagnoses of cancers is a tedious task. Exosomes are secreted by virtually all cell types and have the ability to carry a multitude of biomolecules crucial for intercellular communication, hence, contributing a crucial part in the onset and spread of cancer. These exosomal components can be utilized in the development of markers for diagnostic and prognostic purposes for various cancers. This review emphasized primarily the following topics: exosomes structure and functions, isolation and characterization strategies of exosomes, the role of exosomal contents in cancer with a focus in particular on noncoding RNA and protein, exosomes, and the cancer microenvironment interactions, cancer stem cells, and tumor diagnosis and prognosis based on exosomes.

Novel biomarkers for early detection of gastric cancer

Gastric cancer (GC) remains a leading cause of cancer-related death worldwide. Less than half of GC cases are diagnosed at an advanced stage due to its lack of early symptoms. GC is a heterogeneous disease associated with a number of genetic and somatic mutations. Early detection and effective monitoring of tumor progression are essential for reducing GC disease burden and mortality. The current widespread use of semi-invasive endoscopic methods and radiologic approaches has increased the number of treatable cancers: However, these approaches are invasive, costly, and time-consuming. Thus, novel molecular noninvasive tests that detect GC alterations seem to be more sensitive and specific compared to the current methods. Recent technological advances have enabled the detection of blood-based biomarkers that could be used as diagnostic indicators and for monitoring postsurgical minimal residual disease. These biomarkers include circulating DNA, RNA, extracellular vesicles, and proteins, and their clinical applications are currently being investigated. The identification of ideal diagnostic markers for GC that have high sensitivity and specificity would improve survival rates and contribute to the advancement of precision medicine. This review provides an overview of current topics regarding the novel, recently developed diagnostic markers for GC.

Dysregulation of Serum MicroRNA after Intracerebral Hemorrhage in Aged Mice

Stroke is one of the most common diseases that leads to brain injury and mortality in patients, and intracerebral hemorrhage (ICH) is the most devastating subtype of stroke. Though the prevalence of ICH increases with aging, the effect of aging on the pathophysiology of ICH remains largely understudied. Moreover, there is no effective treatment for ICH. Recent studies have demonstrated the potential of circulating microRNAs as non-invasive diagnostic and prognostic biomarkers in various pathological conditions. While many studies have identified microRNAs that play roles in the pathophysiology of brain injury, few demonstrated their functions and roles after ICH. Given this significant knowledge gap, the present study aims to identify microRNAs that could serve as potential biomarkers of ICH in the elderly. To this end, sham or ICH was induced in aged C57BL/6 mice (18–24 months), and 24 h post-ICH, serum microRNAs were isolated, and expressions were analyzed. We identified 28 significantly dysregulated microRNAs between ICH and sham groups, suggesting their potential to serve as blood biomarkers of acute ICH. Among those microRNAs, based on the current literature, miR-124-3p, miR-137-5p, miR-138-5p, miR-219a-2-3p, miR-135a-5p, miR-541-5p, and miR-770-3p may serve as the most promising blood biomarker candidates of ICH, warranting further investigation.

Advanced technologies for molecular diagnosis of cancer: State of pre-clinical tumor-derived exosome liquid biopsies

Exosomes are membrane-defined extracellular vesicles (EVs) approximately 40-160 ​nm in diameter that are found in all body fluids including blood, urine, and saliva. They act as important vehicles for intercellular communication between both local and distant cells and can serve as circulating biomarkers for disease diagnosis and prognosis. Exosomes play a key role in tumor metastasis, are abundant in biofluids, and stabilize biomarkers they carry, and thus can improve cancer detection, treatment monitoring, and cancer staging/prognosis. Despite their clinical potential, lack of sensitive/specific biomarkers and sensitive isolation/enrichment and analytical technologies has posed a barrier to clinical translation of exosomes. This review presents a critical overview of technologies now being used to detect tumor-derived exosome (TDE) biomarkers in clinical specimens that have potential for clinical translation.

Clinical application and detection techniques of liquid biopsy in gastric cancer

Gastric cancer (GC) is one of the most common tumors worldwide and the leading cause of tumor-related mortality. Endoscopy and serological tumor marker testing are currently the main methods of GC screening, and treatment relies on surgical resection or chemotherapy. However, traditional examination and treatment methods are more harmful to patients and less sensitive and accurate. A minimally invasive method to respond to GC early screening, prognosis monitoring, treatment efficacy, and drug resistance situations is urgently needed. As a result, liquid biopsy techniques have received much attention in the clinical application of GC. The non-invasive liquid biopsy technique requires fewer samples, is reproducible, and can guide individualized patient treatment by monitoring patients' molecular-level changes in real-time. In this review, we introduced the clinical applications of circulating tumor cells, circulating free DNA, circulating tumor DNA, non-coding RNAs, exosomes, and proteins, which are the primary markers in liquid biopsy technology in GC. We also discuss the current limitations and future trends of liquid biopsy technology as applied to early clinical biopsy technology.

Roles of microRNAs and exosomes in Helicobacter pylori associated gastric cancer

Helicobacter pylori (H. pylori) is a common pathogen that infects more than half of the world's population. Its infection can not only lead to a variety of gastrointestinal diseases, such as chronic gastritis and gastric cancer (GC) but also be associated with many extra-gastrointestinal diseases. Exosomes, as a new intercellular information transmission medium, can carry biological signal molecules such as microRNAs (miRNAs) to regulate a variety of cellular physiological activities and are involved in multiple cancer processes. In this article, we provide a systematic review on the role of exosomal miRNAs in H. pylori-associated GC.

The Emerging Role of Exosomal miRNAs as Biomarkers for Early Cancer Detection: A Comprehensive Literature Review

A significant number of cancer-related deaths are recorded globally each year, despite attempts to cure this illness. Medical science is working to develop new medication therapies as well as to find ways to identify this illness as early as possible, even using noninvasive techniques. Early detection of cancer can greatly aid its treatment. Studies into cancer diagnosis and therapy have recently shifted their focus to exosome (EXO) biomarkers, which comprise numerous RNA and proteins. EXOs are minuscule goblet vesicles that have a width of 30 to 140 nm and are released by a variety of cells, including immune, stem, and tumor cells, as well as bodily fluids. According to a growing body of research, EXOs, and cancer appear to be related. EXOs from tumors play a role in the genetic information transfer between tumor and basal cells, which controls angiogenesis and fosters tumor development and spread. To identify malignant activities early on, microRNAs (miRNAs) from cancers can be extracted from circulatory system EXOs. Specific markers can be used to identify cancer-derived EXOs containing miRNAs, which may be more reliable and precise for early detection. Conventional solid biopsy has become increasingly limited as precision and personalized medicine has advanced, while liquid biopsy offers a viable platform for noninvasive diagnosis and prognosis. Therefore, the use of body fluids such as serum, plasma, urine, and salivary secretions can help find cancer biomarkers using technologies related to EXOs.

Correlation and predictive value of serum miR-146b-5p expression during the first trimester of pregnancy with pre-eclampsia

The aim of this study was to investigate the correlation and predictive value of serum miR-146b-5p expression during the first trimester of pregnancy with pre-eclampsia (PE). In total, 32 normal pregnant women (the control group) and 58 subjects with PE were randomly selected from eligible case data. The serum levels of miR-146b-5p, pregnancy associated plasma protein A (PAPP-A) and free beta subunit of human chorionic gonadotropin (free β-hCG) were then detected. Next, we established predictive models of single or multiple markers for PE. The levels of miR-146b-5p in the mild pre-eclampsia (mPE) and severe pre-eclampsia (sPE) groups were higher than the control group and there were significant differences between the three groups (F = 3.424, P = 0.037). The statistical results of the model before and after 200 times 10-fold cross-validation were as follows: miR-146b-5p (AUC = 0.723 vs AUC = 0.710); miR-146b-5p + BMI + MAP + free β-hCG MoM + PAPP-A MoM (AUC = 0.929 vs AUC = 0.851). We found that expression levels of miR-146b-5p in the first trimester were significantly higher in the serum of pregnant women with PE than in the normal pregnancy group. A prediction model in combination with miR-146b-5p and other markers improved the early predictive value for PE.IMPACT STATEMENTWhat is already known on this subject? Pre-eclampsia is a complex systemic disease with hypertension as the main clinical manifestation and causes extensive damage to the body. Some existing maternal biochemical markers have limited value in predicting PE, and new biomarkers with high sensitivity and specificity are urgently needed in clinical practice. There are a variety of abnormal expression miRNAs in PE, however, the relationship between miR-146b-5p and PE has yet to be fully elucidated.What do the results of this study add? We first found that expression levels of serum miR-146b-5p in the first trimester were significantly higher in PE than in a normal pregnancy group. A prediction model a combination of miR-146b-5p and other maternal characteristics and biochemical markers can improve the early predictive value for PE.What are the implications of these findings for clinical practice and/or further research? PE progresses rapidly and has become a severe target organ complication when discovered. Therefore, the early prediction of a high risk of PE, along with early intervention and prevention measures, are of great significance. Compared to maternal biochemical markers, combination of miR-146b-5p and maternal characteristics and biochemical markers can improve the early predictive value for PE.

A panel of blood-derived miRNAs with a stable expression pattern as a potential pan-cancer detection signature

Introduction: MicroRNAs have a significant role in the regulation of the transcriptome. Several miRNAs have been proposed as potential biomarkers in different malignancies. However, contradictory results have been reported on the capability of miRNA biomarkers in cancer detection. The human biological clock involves molecular mechanisms that regulate several genes over time. Therefore, the sampling time becomes one of the significant factors in gene expression studies. Method: In the present study, we have tried to find miRNAs with minimum fluctuation in expression levels at different time points that could be more accurate candidates as diagnostic biomarkers. The small RNA-seq raw data of ten healthy individuals across nine-time points were analyzed to identify miRNAs with stable expression. Results: We have found five oscillation patterns. The stable miRNAs were investigated in 779 small-RNA-seq datasets of eleven cancer types. All miRNAs with the highest differential expression were selected for further analysis. The selected miRNAs were explored for functional pathways. The predominantly enriched pathways were miRNA in cancer and the P53-signaling pathway. Finally, we have found seven miRNAs, including miR-142-3p, miR-199a-5p, miR-223-5p, let-7d-5p, miR-148b-3p, miR-340-5p, and miR-421. These miRNAs showed minimum fluctuation in healthy blood and were dysregulated in the blood of eleven cancer types. Conclusion: We have found a signature of seven stable miRNAs which dysregulate in several cancer types and may serve as potential pan-cancer biomarkers.

Exosome RNA Sequencing as a Tool in the Search for Cancer Biomarkers

Numerous noninvasive methods are currently being used to determine biomarkers for diseases such as cancer. However, these methods are not always precise and reliable. Thus, there is an unmet need for better diagnostic and prognostic biomarkers that will be used to diagnose cancer in early, more treatable stages of the disease. Exosomes are extracellular vesicles of endocytic origin released by the majority of cells. Exosomes contain and transport nucleic acids, proteins, growth factors, and cytokines from their parent cells to surrounding or even distant cells via circulation in biofluids. Exosomes have attracted the interest of researchers, as recent data indicate that exosome content may be indicative of disease stages and may contribute to disease progression via exosome-mediated extracellular communication. Therefore, the contents of these vesicles are being investigated as possible biomarkers for disease diagnosis and prognosis. The functions of exosomes and their contents in disease development are becoming clearer as isolation and analytical methods, such as RNA sequencing, advance. In this review, we discuss current advances and challenges in exosomal content analyses with emphasis on information that can be generated using RNA sequencing. We also discuss how the RNA sequencing of exosomes may be used to discover novel biomarkers for the detection of different stages for various cancers using specific microRNAs that were found to be differentially expressed between healthy controls and cancer-diagnosed subjects.

Feasibility of Leukemia-Derived Exosome Enrichment and Co-isolated dsDNA Sequencing in Acute Myeloid Leukemia Patients: A Proof of Concept for New Leukemia Biomarkers Detection

Simple Summary

The present pilot study aimed at investigating the feasibility of a leukemia-derived exosome enrichment approach followed by exosomal dsDNA target re-sequencing for adult Acute Myeloid Leukemias (AML) marker detection. To our knowledge, this is the first time that a proof-of-concept combining a leukemia-derived exosome enrichment strategy based on a commercial CE-IVD kit and next-generation sequencing was applied in a cohort of adult AML patients. The reported approach is easy, quick and user friendly and gives the possibility of obtaining a good quantity of exosomal dsDNA (composed of exosomal cargo and surrounding DNA) suitable for further analysis. The time-effective procedure opens up future effective clinical applications. This pilot study presents the potential of a proof-of-concept based on exosome analysis to be applied in clinical practice, as well as the feasibility of this kind of investigations using a certified kit, avoiding many additional analyses. It may encourage further studies regarding extracellular vesicles in myeloid neoplasia.

Abstract

Exosomes are extracellular vesicles playing a pivotal role in the intercellular communication. They shuttle different cargoes, including nucleic acids from their cell of origin. For this reason, they have been studied as carriers of tumor markers in different liquid biopsy approaches, in particular for solid tumors. Few data are available concerning exosomes as markers of myeloid neoplasia. To better understand their real potential and the best approach to investigate leukemic exosomes, we present the results of a pilot feasibility study evaluating the application of next-generation sequencing analysis of dsDNA derived from exosomes isolated in 14 adult patients affected by acute myeloid leukemias. In particular, leukemia-derived exosome fractions have been analyzed. The concentration of dsDNA co-extracted with exosomes and the number and types of mutations detected were considered and compared with ones identified in the Bone Marrow (BM) and Peripheral Blood (PB) cells. Exosomal DNA concentration, both considering the cargo and the DNA surrounding the lipid membrane resulted in a linear correlation with leukemic burden. Moreover, exosomal DNA mutation status presented 86.5% of homology with BM and 75% with PB. The results of this pilot study confirmed the feasibility of a leukemia-derived exosome enrichment approach followed by exosomal dsDNA NGS analysis for AML biomarker detection. These data point to the use of liquid biopsy in myeloid neoplasia for the detection of active leukemic cells resident in the BM via a painless procedure.

Comprehensive Analyses of miRNAs Revealed miR-92b-3p, miR-182-5p and miR-183-5p as Potential Novel Biomarkers in Melanoma-Derived Extracellular Vesicles

Extracellular vesicles (EVs) are important mediators in the intercellular communication, influencing the function and phenotype of different cell types within the tumor micro-milieu and thus promote tumor progression. Since EVs safely transport packages of proteins, lipids and also nucleic acids such as miRNAs, EVs and their cargo can serve as diagnostic and prognostic markers. Therefore, the aim of this study was to investigate EV embedded miRNAs specific for melanoma, which could serve as potential biomarkers. In contrast to previous studies, we not only analysed miRNAs from EVs, but also included the miRNA profiles from the EV-secreting cells to identify candidates as suitable biomarkers. While the characterization of EVs derived from normal melanocytes and melanoma cells showed largely comparable properties with regard to size distribution and expression of protein markers, the NGS analyses yielded marked differences for several miRNAs. While miRNA load of EVs derived from normal human epidermal melanocytes (NHEMs) and melanoma cells were very similar, they were highly different from their secreting cells. By comprehensive analyses, six miRNAs were identified to be enriched in both melanoma cells and melanoma cell-derived EVs. Of those, the accumulation of miR-92b-3p, miR-182-5p and miR-183-5p in EVs could be validated in vitro. By functional network generation and pathway enrichment analysis we revealed an association with different tumor entities and signaling pathways contributing melanoma progression. Furthermore, we found that miR-92b-3p, miR-182-5p and miR-183-5p were also enriched in EVs derived from serum of melanoma patients. Our results support the hypothesis that miRNAs derived from EVs can serve as prognostic or diagnostic liquid biopsy markers in melanoma. We identified EV-derived miRNAs and showed that those miRNAs, which were enriched in melanoma cells and EVs, are also found elevated in serum-derived EVs of patients with metastatic melanoma, but not in healthy subjects.

Identification of Two Exosomal miRNAs in Circulating Blood of Cancer Patients by Using Integrative Transcriptome and Network Analysis

Exosomes carry molecules of great biological and clinical interest, such as miRNAs. The contents of exosomes vary between healthy controls and cancer patients. Therefore, miRNAs and other molecules transported in exosomes are considered a potential source of diagnostic and prognostic biomarkers in cancer. Many miRNAs have been detected in recent years. Consequently, a substantial amount of miRNA-related data comparing patients and healthy individuals is available, which contributes to a better understanding of the initiation, development, malignancy, and metastasis of cancer using non-invasive sampling procedures. However, a re-analysis of available ncRNA data is rare. This study used available data about miRNAs in exosomes comparing healthy individuals and cancer patients to identify possible global changes related to the presence of cancer. A robust transcriptomic analysis identified two common miRNAs (miR-495-3p and miR-543) deregulated in five cancer datasets. They had already been implicated in different cancers but not reported in exosomes circulating in blood. The study also examined their target genes and the implications of these genes for functional processes.

Screening of Serum Exosomal miRNAs as Diagnostic Biomarkers for Gastric Cancer Using Small RNA Sequencing

Background/Aim

Exosomal miRNAs are promising tumor biomarkers. This research explored the diagnostic value of serum exosomal miRNAs by analyzing the exosomal miRNAs derived from the serum of gastric cancer patients.

Methods

Deep sequencing of exosomal miRNAs was performed using an Illumina HiSeq2500 sequencer on serum samples from three healthy subjects in the normal control group (group N) and six gastric cancer patients in the gastric cancer treatment group (group T). Bioinformatics analysis was performed on exosomal miRNA profiles to screen differentially expressed miRNA. In addition, target gene prediction, GO, and KEGG pathway enrichment analyses were performed. Finally, the serum exocrine bodies of 24 patients with gastric cancer and 24 normal controls were verified by quantitative reverse transcription-polymerase chain reaction (qRT-PCR) to confirm the findings. The receiver operating characteristic (ROC) curve of the subjects was plotted, and the area under the curve (AUC) was calculated with a 95% confidence interval (CI).

Results

The exosomes were successfully extracted from the serum of gastric cancer patients, which showed a form of goblet vesicles or irregular circles, with an average particle size of approximately 102.3 nm. The exosomal marker proteins, CD9, CD63, TSG101, and calnexin, were positively expressed. Small RNA sequencing detected 15 different types of RNA components in the serum exosomes, and the most abundant one was miRNA. In the screened cohort, the downregulation of seven existing miRNAs and the upregulation of one existing miRNA were observed. Four of them were selected for confirmation, revealing that the expression of miR-10401-3p, miR-1255b-5p, and miR-6736-5p declined significantly in group T (P < 0.05). In addition, the ROC curve showed that the AUC values for these three miRNAs were 0.8333, 0.8316, and 0.8142, respectively; all of them are statistically significant (P < 0.05).

Conclusions

The above three miRNAs found in the serum exosomes from gastric cancer patients might serve as diagnostic biomarkers for gastric cancer.

A Translational Model to Improve Early Detection of Epithelial Ovarian Cancers

Neural network analyses of circulating miRNAs have shown potential as non-invasive screening tests for ovarian cancer. A clinically useful test would detect occult disease when complete cytoreduction is most feasible. Here we used murine xenografts to sensitize a neural network model to detect low volume disease and applied the model to sera from 75 early-stage ovarian cancer cases age-matched to 200 benign adnexal masses or healthy controls. The 14-miRNA model efficiently discriminated tumor bearing animals from controls with 100% sensitivity down to tumor inoculums of 50,000 cells. Among early-stage patient samples, the model performed well with 73% sensitivity at 91% specificity. Applied to a population with 1% disease prevalence, we hypothesize the model would detect most early-stage ovarian cancers while maintaining a negative predictive value of 99.97% (95% CI 99.95%-99.98%). Overall, this supports the concept that miRNAs may be useful as screening markers for early-stage disease.

The Clinical Significance of Transfer RNAs Present in Extracellular Vesicles

Extracellular vesicles (EVs) are important for intercellular signalling in multi-cellular organisms. However, the role of mature transfer RNAs (tRNAs) and tRNA fragments in EVs has yet to be characterised. This systematic review aimed to identify up-to-date literature on tRNAs present within human EVs and explores their potential clinical significance in health and disease. A comprehensive and systematic literature search was performed, and the study was conducted in accordance with PRISMA guidelines. Electronic databases MEDLINE and EMBASE were searched up until 1 January 2022. From 685 papers, 60 studies were identified for analysis. The majority of papers reviewed focussed on the role of EV tRNAs in cancers (31.7%), with numerous other conditions represented. Blood and cell lines were the most common EV sources, representing 85.9% of protocols used. EV isolation methods included most known methods, precipitation being the most common (49.3%). The proportion of EV tRNAs was highly variable, ranging between 0.04% to >95% depending on tissue source. EV tRNAs are present in a multitude of sources and show promise as disease markers in breast cancer, gastrointestinal cancers, and other diseases. EV tRNA research is an emerging field, with increasing numbers of papers highlighting novel methodologies for tRNA and tRNA fragment discovery.

Evaluation of exosomal non-coding RNAs in cancer using high-throughput sequencing

Clinical oncologists need more reliable and non-invasive diagnostic and prognostic biomarkers to follow-up cancer patients. However, the existing biomarkers are often invasive and costly, emphasizing the need for the development of biomarkers to provide convenient and precise detection. Extracellular vesicles especially exosomes have recently been the focus of translational research to develop non-invasive and reliable biomarkers for several diseases such as cancers, suggesting as a valuable source of tumor markers. Exosomes are nano-sized extracellular vesicles secreted by various living cells that can be found in all body fluids including serum, urine, saliva, cerebrospinal fluid, and ascites. Different molecular and genetic contents of their origin such as nucleic acids, proteins, lipids, and glycans in a stable form make exosomes a promising approach for various cancers' diagnoses, prediction, and follow-up in a minimally invasive manner. Since exosomes are used by cancer cells for intercellular communication, they play a critical role in the disease process, highlighting the importance of their use as clinically relevant biomarkers. However, regardless of the advantages that exosome-based diagnostics have, they suffer from problems regarding their isolation, detection, and characterization of their contents. This study reviews the history and biogenesis of exosomes and discusses non-coding RNAs (ncRNAs) and their potential as tumor markers in different types of cancer, with a focus on next generation sequencing (NGS) as a detection method. Moreover, the advantages and challenges associated with exosome-based diagnostics are also presented.

Identification of Combinations of Plasma lncRNAs and mRNAs as Potential Biomarkers for Precursor Lesions and Early Gastric Cancer

Patients with gastric cancer (GC) are usually first diagnosed at an advanced stage due to the absence of obvious symptoms at an early GC (EGC) stage. Therefore, it is necessary to identify an effective screening method to detect precursor lesions of GC (PLGC) and EGC to increase the 5-year survival rate of patients. Cell-free RNA, as a biomarker, has shown potential in early diagnosis, personalised treatment, and prognosis of cancer. In this study, six RNAs (CEBPA-AS1, INHBA-AS1, AK001058, UCA1, PPBP, and RGS18) were analysed via real-time quantitative polymerase chain reaction (RT-qPCR) using the plasma of patients with EGC and PLGC to identify diagnostic biomarkers. The receiver operating characteristic (ROC) curve analysis was used to evaluate the diagnostic accuracy. Among the six RNAs, four lncRNAs (CEBPA-AS1, INHBA-AS1, AK001058, and UCA1) were upregulated and two mRNAs (PPBP and RGS18) were downregulated in the plasma of patients with PLGC and EGC. According to the findings of the ROC analysis, the four-RNA combination of INHBA-AS1, AK001058, UCA1, and RGS18 had the highest area under the curve (AUC) value for determining risk of GC in patients with PLGC and the six-RNA combination including CEBPA-AS1, INHBA-AS1, AK001058, UCA1, PPBP, and RGS18 had the highest AUC value for determining the risk of GC in patients with EGC. The results suggest the potential usefulness of noninvasive biomarkers for the molecular diagnosis of GC at earlier stages.

Exosomes Derived from Radioresistant Breast Cancer Cells Promote Therapeutic Resistance in Naïve Recipient Cells

Radiation resistance is a significant challenge in the treatment of breast cancer in humans. Human breast cancer is commonly treated with surgery and adjuvant chemotherapy/radiotherapy, but recurrence and metastasis upon the development of therapy resistance results in treatment failure. Exosomes are extracellular vesicles secreted by most cell types and contain biologically active cargo that, when transferred to recipient cells, can influence the cells’ genome and proteome. We propose that exosomes secreted by radioresistant (RR) cells may be able to disseminate the RR phenotype throughout the tumour. Here, we isolated exosomes from the human breast cancer cell line, MDA-MB-231, and the canine mammary carcinoma cell line, REM134, and their RR counterparts to investigate the effects of exosomes derived from RR cells on non-RR recipient cells. Canine mammary cancer cells lines have previously been shown to be excellent translational models of human breast cancer. This is consistent with our current data showing that exosomes derived from RR cells can increase cell viability and colony formation in naïve recipient cells and increase chemotherapy and radiotherapy resistance, in both species. These results are consistent in cancer stem cell and non-cancer stem cell populations. Significantly, exosomes derived from RR cells increased the tumoursphere-forming ability of recipient cells compared to exosomes derived from non-RR cells. Our results show that exosomes are potential mediators of radiation resistance that could be therapeutically targeted.

Exosomes and Exosomal circRNAs: The Rising Stars in the Progression, Diagnosis and Prognosis of Gastric Cancer

Gastric cancer (GC) is a common malignant tumor affecting human health, with occult onset and poor prognosis. Exosomes are extracellular vesicles secreted by almost all cells, which can reflect the state of source cells or tissues. It is reported that exosomes are involved in almost all processes of GC. Exosomes provided a window to understand changes in cell or tissue states by carrying active components such as circular RNAs (circRNAs). CircRNAs are a naturally occurring class of endogenous noncoding RNAs and abnormal expression during the occurrence and development of GC. Exosomal circRNAs are those circRNAs stably existing in exosomes and having high clinical values as novel potential diagnosis and prognosis biomarkers of GC, which have the characteristics of abnormal expression, tissue specificity and development stage specificity. Herein, we briefly summarize the functions and roles and the current research progress of exosomes and exosomal circRNAs in GC with a focus on the potential application for GC progression, diagnosis and prognosis. We also prospected the clinical application of exosomes and exosomal circRNAs in the future.

Liquid biopsy from research to clinical practice: focus on non-small cell lung cancer

INTRODUCTION

In the current era of personalized medicine, liquid biopsy has acquired a relevant importance in patient management of advanced stage non-small cell lung cancer (NSCLC). As a matter of fact, liquid biopsy may supplant the problem of inadequate tissue for molecular testing. The term 'liquid biopsy' refers to a number of different biological fluids, but is most clearly associated with plasma-related platforms. It must be taken into account that pre-analytical processing and the selection of the appropriate technology according to the clinical context may condition the results obtained. In addition, novel clinical applications beyond the evaluation of the molecular status of predictive biomarkers are currently under investigation.

AREAS COVERED

This review summarizes the available evidence on pre-analytical issues and different clinical applications of liquid biopsies in NSCLC patients.

EXPERT OPINION

Liquid biopsy should be considered not only as a valid alternative but as complementary to tissue-based molecular approaches. Careful attention should be paid to the optimization and standardization of all phases of liquid biopsy samples management in order to determine a significant improvement in either sensitivity or specificity, while significant reducing the number of 'false negative' or 'false positive' molecular results.

Circulating exosomal miRNAs and cancer early diagnosis

Microribonucleic acids (miRNAs) are small non-coding ribonucleic acids (ncRNAs), which can affect recognition of homologous sequences and interfere with transcription. It plays key roles in the initiation, development, resistance, metastasis or recurrence of cancers. Identifying circulatory indicators will positively improve the prognosis and quality of life of patients with early cancer. Previous studies have shown that miRNA is highly involved in cancer. In addition, miRNA derived from cancers can be encapsulated as exosomes and further extracted into circulatory systems to realize malignant functions. It indicates that circulating exosome-derived miRNAs have the potential to replace conventional biomarkers as cancer derived exosomes carrying miRNAs can be identified by specific markers and might be more stable and accurate for early diagnosis.

Emerging Role of Extracellular Vesicles in Biomarking the Gastrointestinal Diseases

INTRODUCTION

Extracellular vesicles (EVs) play an important role in cell-cell communication and regulation of various cellular functions under physiological and pathophysiological conditions through transferring their cargo to recipient cells. Molecular constituents of EVs are a fingerprinting profile of secreting cells which can be used as promising prognostic, diagnostic, and drug-response biomarkers in clinical settings.

AREAS COVERED

The present study provides a brief introduction about the biology of EVs and reviews methodologies used for EV isolation and characterization as well as high-throughput strategies to analyze EV contents. Furthermore, this review highlights the importance and unique role of EVs in the development and progression of gastrointestinal (GI) diseases, especially GI cancers, and then discusses their potential use, particularly those isolated from body fluids, in diagnosis and prognosis of GI diseases.

EXPERT OPINION

In-depth analysis of EV content can lead to the identification of new potential biomarkers for early diagnosis and prognosis prediction of GI diseases. The use of a more targeted approach by establishing more reproducible and standardized methods to decrease variations and obtain desired EV population as well as revisiting large pools of identified biomarkers and their evaluation in larger patient cohorts can result in the introduction of more reliable biomarkers in clinic.

The distinct roles of exosomes in tumor-stroma crosstalk within gastric tumor microenvironment

Gastric cancer (GC) development is a complex process displaying polytropic cell and molecular landscape within gastric tumor microenvironment (TME). Stromal cells in TME, including fibroblasts, endothelial cells, mesenchymal stem cells, and various immune cells, support tumor growth, metastasis, and recurrence, functioning as the soil for gastric tumorigenesis. Importantly, exosomes secreted by either stromal cells or tumor cells during tumor-stroma crosstalk perform as crucial transporter of agents including RNAs and proteins for cell-cell communication in GC pathogenesis. Therefore, given the distinct roles of exosomes secreted by various cell types in GC TME, increasing evidence has indicated that exosomes present as new biomarkers for GC diagnosis and prognosis and shed light on novel approaches for GC treatment.

Role of Exosomal Non-coding RNAs in Gastric Cancer: Biological Functions and Potential Clinical Applications

Gastric cancer (GC) is one of the most common fatal cancers worldwide. The communication between GC and other cells in the GC microenvironment directly affects GC progression. Recently, exosomes have been revealed as new players in intercellular communication. They play an important role in human health and diseases, including cancer, owing to their ability to carry various bioactive molecules, including non-coding RNAs (ncRNAs). NcRNAs, including micro RNAs, long non-coding RNAs, and circular RNAs, play a significant role in various pathophysiological processes, especially cancer. Increasing evidence has shown that exosomal ncRNAs are involved in the regulation of tumor proliferation, invasion, metastasis, angiogenesis, immune regulation, and treatment resistance in GC. In addition, exosomal ncRNAs have promising potential as diagnostic and prognostic markers for GC. Considering the biocompatibility of exosomes, they can also be used as biological carriers for targeted therapy. This review summarizes the current research progress on exosomal ncRNAs in gastric cancer, focusing on their biological role in GC and their potential as new biomarkers for GC and therapeutics. Our review provides insight into the mechanisms involved in GC progression, which may provide a new point cut for the discovery of new diagnostic markers and therapeutic strategies.

Exosomes Promote Pre-Metastatic Niche Formation in Gastric Cancer

Gastric cancer has a high rate of metastasis, during which pre-metastatic niches (PMN) provide a supportive environment for the upcoming tumor cells. Exosomes are bilayer vesicles secreted by cells containing biological information that mediates communication between cells. Using exosomes, gastric cancer cells establish PMN remotely in multifarious perspectives, including immunosuppression, stroma remodeling, angiogenesis, mesothelial mesenchymal transformation, and organotropism. In turn, the cell components in PMN secrete exosomes that interact with each other and provide onco-promoting signals. In this review, we highlight the role of exosomes in PMN formation in gastric cancer and discuss their potential values in gastric cancer metastasis diagnosis, prevention, and treatment.

In Vivo Stimulation of α- and β-Adrenoceptors in Mice Differentially Alters Small RNA Content of Circulating Extracellular Vesicles

When myocardial function is compromised as in heart failure (HF), there is activation of the sympathetic nervous system with elevated circulating catecholamine levels. These catecholamines activate cardiac and extra-cardiac adrenergic receptors (ARs). Interest in secreted extracellular vesicles (EVs) from the heart is growing and in HF, it is not known whether excessive activation of α- or β-adrenergic receptors (ARs) could induce specific changes in EV content. In this study, we have evaluated, by next generation sequencing, the small RNA content, including micro-RNAs (miRs), of circulating EVs of mice exposed to chronic selective α- or β- AR stimulation. EVs from mouse blood were purified by differential ultracentrifugation resulting in EVs with an average size of 116.6 ± 4.8 nm that by immunoblotting included protein markers of EVs. We identified the presence of miRs in blood EVs using miR-21-5p and -16-5p real-time PCR as known constituents of blood exosomes that make up a portion of EVs. We next performed next generation sequencing (NGS) of small non-coding RNAs found in blood EVs from mice following 7 days of chronic treatment with isoproterenol (ISO) or phenylephrine (PE) to stimulate α- or β-ARs, respectively. PE increased the percent of genomic repeat region reads and decreased the percent of miR reads. In miR expression analysis, PE and ISO displayed specific patterns of miR expression that suggests differential pathway regulation. The top 20 KEGG pathways predicted by differential expressed miRs show that PE and ISO share 11 of 20 pathways analyzed and reveal also key differences including three synapse relative pathways induced by ISO relative to PE treatment. Both α-and β-AR agonists can alter small RNA content of circulating blood EVs/exosomes including differential expression and loading of miRs that indicate regulation of distinct pathways. This study provides novel insight into chronic sympathetic nervous system activation in HF where excessive catecholamines may not only participate in pathological remodeling of the heart but alter other organs due to secretion of EVs with altered miR content.

The role and application of small extracellular vesicles in gastric cancer

Gastric cancer (GC) is a common tumour that affects humans worldwide, is highly malignant and has a poor prognosis. Small extracellular vesicles (sEVs), especially exosomes, are nanoscale vesicles released by various cells that deliver bioactive molecules to recipient cells, affecting their biological characteristics, changing the tumour microenvironment and producing long-distance effects. In recent years, many studies have clarified the mechanisms by which sEVs function with regard to the initiation, progression, angiogenesis, metastasis and chemoresistance of GC. These molecules can function as mediators of cell-cell communication in the tumour microenvironment and might affect the efficacy of immunotherapy. Due to their unique physiochemical characteristics, sEVs show potential as effective antitumour vaccines as well as drug carriers. In this review, we summarize the roles of sEVs in GC and highlight the clinical application prospects in the future.

Isolation and characterization of extracellular vesicles for clinical applications in cancer - time for standardization?

Extracellular vesicles (EVs) are nanometer sized lipid enclosed particles released by all cell types into the extracellular space and biological fluids in vivo, and into cell culture media in vitro. An important physiological role of EVs is cell-cell communication. EVs interact with, and deliver, their contents to recipient cells in a functional capacity; this makes EVs desirable vehicles for the delivery of therapeutic cargoes. In addition, as EVs contain proteins, lipids, glycans, and nucleic acids that reflect their cell of origin, their potential utility in disease diagnosis and prognostication is of great interest. The number of published studies analyzing EVs and their contents in the pre-clinical and clinical setting is rapidly expanding. However, there is little standardization as to what techniques should be used to isolate, purify and characterize EVs. Here we provide a comprehensive literature review encompassing the use of EVs as diagnostic and prognostic biomarkers in cancer. We also detail their use as therapeutic delivery vehicles to treat cancer in pre-clinical and clinical settings and assess the EV isolation and characterization strategies currently being employed. Our report details diverse isolation strategies which are often dependent upon multiple factors such as biofluid type, sample volume, and desired purity of EVs. As isolation strategies vary greatly between studies, thorough EV characterization would be of great importance. However, to date, EV characterization in pre-clinical and clinical studies is not consistently or routinely adhered to. Standardization of EV characterization so that all studies image EVs, quantitate protein concentration, identify the presence of EV protein markers and contaminants, and measure EV particle size and concentration is suggested. Additionally, the use of RNase, DNase and protease EV membrane protection control experiments is recommended to ensure that the cargo being investigated is truly EV associated. Overall, diverse methodology for EV isolation is advantageous as it can support different sample types and volumes. Nevertheless, EV characterization is crucial and should be performed in a rigorous manor.

An integrated workflow for biomarker development using microRNAs in extracellular vesicles for cancer precision medicine

EV-miRNAs are microRNA (miRNA) molecules encapsulated in extracellular vesicles (EVs), which play crucial roles in tumor pathogenesis, progression, and metastasis. Recent studies about EV-miRNAs have gained novel insights into cancer biology and have demonstrated a great potential to develop novel liquid biopsy assays for various applications. Notably, compared to conventional liquid biomarkers, EV-miRNAs are more advantageous in representing host-cell molecular architecture and exhibiting higher stability and specificity. Despite various available techniques for EV-miRNA separation, concentration, profiling, and data analysis, a standardized approach for EV-miRNA biomarker development is yet lacking. In this review, we performed a substantial literature review and distilled an integrated workflow encompassing important steps for EV-miRNA biomarker development, including sample collection and EV isolation, EV-miRNA extraction and quantification, high-throughput data preprocessing, biomarker prioritization and model construction, functional analysis, as well as validation. With the rapid growth of "big data", we highlight the importance of efficient mining of high-throughput data for the discovery of EV-miRNA biomarkers and integrating multiple independent datasets for in silico and experimental validations to increase the robustness and reproducibility. Furthermore, as an efficient strategy in systems biology, network inference provides insights into the regulatory mechanisms and can be used to select functionally important EV-miRNAs to refine the biomarker candidates. Despite the encouraging development in the field, a number of challenges still hinder the clinical translation. We finally summarize several common challenges in various biomarker studies and discuss potential opportunities emerging in the related fields.

Small Extracellular Vesicles: A Novel Avenue for Cancer Management

Extracellular vesicles are small membrane particles derived from various cell types. EVs are broadly classified as ectosomes or small extracellular vesicles, depending on their biogenesis and cargoes. Numerous studies have shown that EVs regulate multiple physiological and pathophysiological processes. The roles of small extracellular vesicles in cancer growth and metastasis remain to be fully elucidated. As endogenous products, small extracellular vesicles are an ideal drug delivery platform for anticancer agents. However, several aspects of small extracellular vesicle biology remain unclear, hindering the clinical implementation of small extracellular vesicles as biomarkers or anticancer agents. In this review, we summarize the utility of cancer-related small extracellular vesicles as biomarkers to detect early-stage cancers and predict treatment outcomes. We also review findings from preclinical and clinical studies of small extracellular vesicle-based cancer therapies and summarize interventional clinical trials registered in the United States Food and Drug Administration and the Chinese Clinical Trials Registry. Finally, we discuss the main challenges limiting the clinical implementation of small extracellular vesicles and recommend possible approaches to address these challenges.

The Significance of Exosomal RNAs in the Development, Diagnosis, and Treatment of Gastric Cancer

Gastric cancer (GC) is one of the most common malignancies in the world. Exosomes, a subset of extracellular vesicles with an average diameter of 100 nm, contain and transfer a variety of functional macromolecules such as proteins, lipids, and nucleic acids. A large number of studies indicated that exosomes can play a significant role in the initiation and development of GC via facilitating intercellular communication between gastric cancer cells and microenvironment. Exosomal RNAs, one of the key functional cargos, are involved in the pathogenesis, development, and metastasis of GC. In addition, recent studies elucidated that exosomal RNAs may serve as diagnostic and prognostic biomarkers or therapeutic targets for GC. In this review, we summarized the function of exosomal RNA in the tumorigenesis, progression, diagnosis, and treatment of GC, which may further unveil the functions of exosome and promote the potentially diagnostic and therapeutic application of exosomes in GC.

A novel combination of serum microRNAs for the detection of early gastric cancer

BACKGROUND

The aim of this study was to identify serum miRNAs that discriminate early gastric cancer (EGC) samples from non-cancer controls using a large cohort.

METHODS

This retrospective case-control study included 1417 serum samples from patients with EGC (seen at the National Cancer Center Hospital in Tokyo between 2008 and 2012) and 1417 age- and gender-matched non-cancer controls. The samples were randomly assigned to discovery and validation sets and the miRNA expression profiles of whole serum samples were comprehensively evaluated using a highly sensitive DNA chip (3D-Gene^®) designed to detect 2565 miRNA sequences. Diagnostic models were constructed using the levels of several miRNAs in the discovery set, and the diagnostic performance of the model was evaluated in the validation set.

RESULTS

The discovery set consisted of 708 samples from EGC patients and 709 samples from non-cancer controls, and the validation set consisted of 709 samples from EGC patients and 708 samples from non-cancer controls. The diagnostic EGC index was constructed using four miRNAs (miR-4257, miR-6785-5p, miR-187-5p, and miR-5739). In the discovery set, a receiver operating characteristic curve analysis of the EGC index revealed that the area under the curve (AUC) was 0.996 with a sensitivity of 0.983 and a specificity of 0.977. In the validation set, the AUC for the EGC index was 0.998 with a sensitivity of 0.996 and a specificity of 0.953.

CONCLUSIONS

A novel combination of four serum miRNAs could be a useful non-invasive diagnostic biomarker to detect EGC with high accuracy. A multicenter prospective study is ongoing to confirm the present observations.

The Emerging Role of miRNAs for the Radiation Treatment of Pancreatic Cancer

Simple Summary

Pancreatic cancer is an aggressive disease with a high mortality rate. Radiotherapy is one treatment option within a multimodal therapy approach for patients with locally advanced, non-resectable pancreatic tumors. However, radiotherapy is only effective in about one-third of the patients. Therefore, biomarkers that can predict the response to radiotherapy are of utmost importance. Recently, microRNAs, small non-coding RNAs regulating gene expression, have come into focus as there is growing evidence that microRNAs could serve as diagnostic, predictive and prognostic biomarkers in various cancer entities, including pancreatic cancer. Moreover, their high stability in body fluids such as serum and plasma render them attractive candidates for non-invasive biomarkers. This article describes the role of microRNAs as suitable blood biomarkers and outlines an overview of radiation-induced microRNAs changes and the association with radioresistance in pancreatic cancer.

Abstract

Today, pancreatic cancer is the seventh leading cause of cancer-related deaths worldwide with a five-year overall survival rate of less than 7%. Only 15–20% of patients are eligible for curative intent surgery at the time of diagnosis. Therefore, neoadjuvant treatment regimens have been introduced in order to downsize the tumor by chemotherapy and radiotherapy. To further increase the efficacy of radiotherapy, novel molecular biomarkers are urgently needed to define the subgroup of pancreatic cancer patients who would benefit most from radiotherapy. MicroRNAs (miRNAs) could have the potential to serve as novel predictive and prognostic biomarkers in patients with pancreatic cancer. In the present article, the role of miRNAs as blood biomarkers, which are associated with either radioresistance or radiation-induced changes of miRNAs in pancreatic cancer, is discussed. Furthermore, the manuscript provides own data of miRNAs identified in a pancreatic cancer mouse model as well as radiation-induced miRNA changes in the plasma of tumor-bearing mice.

Effects of exercise on exosome release and cargo in in vivo and ex vivo models: A systematic review

Exercise-released exosomes have been identified as novel players to mediate cell-to-cell communication in promoting systemic beneficial effects. This review aimed to systematically investigate the effects of exercise on exosome release and cargo, as well as provide an overview of their physiological implications. Among the 436 articles obtained in the database search (WOS, Scopus, and PubMed), 19 articles were included based on eligibility criteria. Results indicate that exercise promotes the release of exosomes without modification of its vesicle size. The literature has primarily shown an exercise-driven increase in exosome markers (Alix, CD63, CD81, and Flot-1), along with other exosome-carried proteins, into circulation. However, exosome isolation, characterization, and phenotyping methodology, as well as timing of sample recovery following exercise can influence the analysis and interpretation of findings. Moreover, a large number of exosome-carried microRNAs (miRNAs), including miR-1, miR-133a, miR-133b, miR-206, and miR-486, in response to exercise are involved in the modulation of proliferation and differentiation of skeletal muscle tissue, although antigen-presenting cells, leukocytes, endothelial cells, and platelets are the main sources of exosome release into the circulation. Collectively, with the physiological implications as evidenced by the ex vivo trials, the release of exercise-promoted exosomes and their cargo could provide the potential therapeutic applications via the role of intercellular communication.