MiR-21-5p in urinary extracellular vesicles is a novel biomarker of urothelial carcinoma

The diagnostic accuracy of urine-derived exosomes for bladder cancer: a systematic review and meta-analysis

INTRODUCTION

Urine-derived exosomes could potentially be biomarkers for bladder cancer (BC) diagnosis. This study aimed to systematically evaluate the diagnostic worth of urine-derived exosomes in BC patients through a meta-analysis of diverse studies.

METHODS

A systematic search was carried out in PubMed, Web of Science, Embase, Cochrane, and CNKI databases to obtain the literature concerning the diagnosis of BC via urine-derived exosomes. A literature retrieval strategy was devised to pick articles and extract needed data from the literature. QUADS-2 was used to evaluate the quality of the included literatures, and the aggregated diagnostic effect was assessed by calculating the area under the aggregated SROC curve. All statistical analyses and plots were conducted with STATA 14.0 and RevMan5.3.

RESULTS

A total of 678 articles were retrieved by means of the search strategy of the online database. Through screening, 21 articles were obtained, involving 3348 participants and 77 studies. The meta-analysis of the results indicated that urinary exosomes had a combined sensitivity of 0.75, a specificity of 0.77, and a combined AUC of 0.83 for the diagnosis of BC, suggesting that urine-derived exosomes have a relatively satisfactory diagnostic effect in the detection of BC. Among the subgroups classified by biomarker, long non-coding RNAs (lncRNAs) had the highest comprehensive sensitivity (SEN = 0.78), and miRNAs had the highest comprehensive specificity (SPN = 0.81). In other subgroup analyses, the biomarker panel for multiple exosomes combined diagnosis demonstrated the best diagnostic efficacy, with a combined the area under the curve ( AUC) of 0.87.

CONCLUSIONS

As a novel biomarker, urine-derived exosomes have significant diagnostic prospects in the diagnosis of BC. Nevertheless, their application in clinical settings still demands a considerable number of clinical trials to confirm their clinical feasibility and practicability.

Exosomal non-coding RNAs (ncRNAs) as potential biomarkers in tumor early diagnosis

Exosomes, extracellular vesicles carrying a cargo rich in various non-coding RNAs (ncRNAs), have emerged as crucial mediators of intercellular communication. Their stability, abundance, and specificity make exosomal ncRNAs promising candidates for biomarker discovery. The discovery of exosomal ncRNAs has unveiled a novel avenue for the exploration of biomarkers in tumor early diagnosis. This review consolidates current knowledge on the role of exosomal ncRNAs as potential biomarkers in the early detection of various tumors. We provide an overview of recent studies demonstrating the diagnostic potential of exosomal ncRNAs across multiple cancer types, highlighting their sensitivity, specificity, and feasibility for early detection. This review underscores the potential of exosomal ncRNAs as non-invasive biomarkers for early tumor diagnosis, paving the way for improved clinical outcomes through timely intervention and personalized management strategies.

Bladder cancer: non-coding RNAs and exosomal non-coding RNAs

Bladder cancer (BCa) is a highly prevalent type of cancer worldwide, and it is responsible for numerous deaths and cases of disease. Due to the diverse nature of this disease, it is necessary to conduct significant research that delves deeper into the molecular aspects, to potentially discover novel diagnostic and therapeutic approaches. Lately, there has been a significant increase in the focus on non-coding RNAs (ncRNAs), including microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs), due to their growing recognition for their involvement in the progression and manifestation of BCa. The interest in exosomes has greatly grown due to their potential for transporting a diverse array of active substances, including proteins, nucleic acids, carbohydrates, and lipids. The combination of these components differs based on the specific cell and its condition. Research indicates that using exosomes could have considerable advantages in identifying and forecasting BCa, offering a less invasive alternative. The distinctive arrangement of the lipid bilayer membrane found in exosomes is what makes them particularly effective for administering treatments aimed at managing cancer. In this review, we have tried to summarize different ncRNAs that are involved in BCa pathogenesis. Moreover, we highlighted the role of exosomal ncRNAs in BCa.

Urinary extracellular vesicles-encapsulated miRNA signatures: A new paradigm for urinary bladder cancer diagnosis and classification

Bladder cancer (BCa) stands as prevalent malignancy of the urinary system globally, especially among men. The clinical classification of BCa into non-muscle invasive bladder cancer (NMIBC) and muscle-invasive bladder cancer (MIBC) is crucial for prognosis and treatment decisions. However, challenges persist in current diagnostic methods like Urine cytopathology that shows poor sensitivity therefore compromising on accurately diagnosing and monitoring BCa. In recent years, research has emphasized the importance of identifying urine and blood-based specific biomarkers for BCa that can enable early and precise diagnosis, effective tumor classification, and monitoring. The convenient proximity of urine with the urinary bladder epithelium makes urine a good source of noninvasive biomarkers, in particular urinary EVs because of the packaged existence of tumor-associated molecules. Therefore, the review assesses the potential of urinary extracellular vesicles (uEVs) as noninvasive biomarkers for BCa. We have elaborately reviewed and discussed the research that delves into the role of urinary EVs in the context of BCa diagnosis and classification. Extensive research has been dedicated to investigating differential microRNA (miRNA) expressions, with the goal of establishing distinct, noninvasive biomarkers for BCa. The identification of such biomarkers has the potential to revolutionize early detection, risk stratification, therapeutic interventions, and ultimately, the long-term prognosis of BCa patients. Despite notable advancements, inconsistencies persist in the biomarkers identified, methodologies employed, and study populations. This review meticulously compiles reported miRNA biomarkers, critically assessing the variability and discrepancies observed in existing research. By synthesizing these findings, the article aims to direct future studies toward a more cohesive and dependable approach in BCa biomarker identification, fostering progress in patient care and management.

Urinary exosomes: Potential diagnostic markers and application in bladder cancer

Background

The exosome is a critical component of the intercellular communication., playing a vital role in regulating cell function. These small vesicles contain proteins, mRNAs, miRNAs, and lncRNAs, surrounded by lipid bilayer substances. Most cells in the human body can produce exosomes, released into various body fluids such as urine, blood, and cerebrospinal fluid. Bladder cancer is the most common tumor in the urinary system, with high recurrence and metastasis rates. Early diagnosis and treatment are crucial for improving patient outcomes.

Methods

This study employed the PubMed search engine to retrieve publicly accessible data pertaining to urinary exosomes.

Results

We summarize the origins and intricate biological characteristics of urinary exosomes, the introduction of research methodologies used in basic experiments to isolate and analyze these exosomes, the discussion of their applications and progress in the diagnosis and treatment of bladder cancer, and the exploration of the current limitations associated with using urinary exosomes as molecular biomarkers for diagnosing bladder cancer.

Conclusion

Exosomes isolated from urine may be used as molecular biomarkers for early detection of bladder cancer.

Harnessing GMNP-loaded BMSC-derived EVs to target miR-3064-5p via MEG3 overexpression: Implications for diabetic osteoporosis therapy in rats

Diabetic osteoporosis (DO) is a significant complication of diabetes, characterized by a decrease in bone mineral density and an increase in fracture risk. Magnetic nanoparticles (GMNPs) have emerged as potential drug carriers for various therapeutic applications. This study investigated the molecular mechanism of GMNPs loaded with bone marrow mesenchymal stem cell (BMSC) derived extracellular vesicles (EVs) overexpressing MEG3 target miR-3064-5p to induce NR4A3 for treating DO in rats. Initial analysis was carried out on GEO datasets GSE7158 and GSE62589, revealing a notable downregulation of NR4A3 in osteoporotic samples. Subsequent in vitro studies demonstrated the effective uptake of BMSC-EVs-MEG3 by osteoblasts and its potential to inhibit miR-3064-5p, activating the PINK1/Parkin signaling pathway and thus promoting mitochondrial autophagy, osteoblast proliferation, and differentiation. In vivo, experiments using DO rat models further substantiated the therapeutic efficacy of GMNPE-EVs-MEG3 in alleviating osteoporosis symptoms. In conclusion, GMNPs loaded with BMSC-EVs, through the delivery of MEG3 targeting miR-3064-5p, can effectively promote NR4A3 expression, activate the PINK1/Parkin pathway, and thereby enhance osteoblast proliferation and differentiation, offering a promising treatment for DO.

Recent research on material-based methods for isolation of extracellular vesicles

Extracellular vesicles (EVs) are nanoparticles secreted by cells with a closed phospholipid bilayer structure, which can participate in various physiological and pathological processes and have significant clinical value in disease diagnosis, targeted therapy and prognosis assessment. EV isolation methods currently include differential ultracentrifugation, ultrafiltration, size exclusion chromatography, immunoaffinity, polymer co-precipitation and microfluidics. In addition, material-based biochemical or biophysical approaches relying on intrinsic properties of the material or its surface-modified functionalized monomers, demonstrated unique advantages in the efficient isolation of EVs. In order to provide new ideas for the subsequent development of material-based EV isolation methods, this review will focus on the principle, research status and application prospects of material-based EV isolation methods based on different material carriers and functional monomers.

Urinary markers for bladder cancer diagnosis: A review of current status and future challenges

Bladder cancer is a common urological cancer with a high recurrence rate that requires long-term follow-up, and early detection positively affects prognosis. To date, the initial diagnosis and follow-up for bladder cancer rely on cystoscopy, which is an invasive and expensive procedure. Therefore, urinary markers for the detection of bladder cancer have attracted research attention for decades to reduce unnecessary cystoscopies. Urine, which is in continuous contact with bladder cancer, is considered a suitable fluid for providing tumor information. Urinary cytology is the only widely used urinary marker in clinical practice; however, it has poor sensitivity for low-grade tumors; indicating the need for novel urinary markers. Considerable research has been conducted on this topic over the years, resulting in a complex landscape with a wide range of urinary markers, including protein-, exfoliated cell-, RNA-, DNA-, and extracellular vesicle-based markers. Although some of these markers have been approved by the U.S. Food and Drug Administration and are commercially available, their use in clinical practice is limited. To facilitate clinical application, potential urinary markers must withstand prospective clinical trials and be easy for patients and clinicians to understand and utilize in a clinical context. This review provides a comprehensive overview of currently available and recently reported promising urinary markers for bladder cancer. Additionally, the challenges and the prospects of these urinary markers for clinical implementation in bladder cancer treatment were discussed.

Matrix metalloproteinase‑1 and microRNA‑486‑5p in urinary exosomes can be used to detect early lung cancer: A preliminary report

The present study describes a novel molecular-genetic method suitable for lung cancer (LC) screening in the work-place and at community health centers. Using urinary-isolated exosomes from 35 patients with LC and 40 healthy volunteers, the expression ratio of MMP-1/CD63, and the relative expression levels of both microRNA (miRNA)-21 and miRNA-486-5p were measured. MMP-1/CD63 expression ratio was significantly higher in patients with LC than in the healthy controls {1.342 [95% confidence interval (CI): 0.890-1.974] vs. 0.600 (0.490-0.900); P<0.0001}. The relative expression of miRNA-486-5p in male healthy controls was significantly different from that in female healthy controls, whereas there was no significant difference in miRNA-21. Receiver operating characteristic curve (ROC) analysis of MMP-1/CD63 showed 92.5% sensitivity and 54.3% specificity, whereas miRNA-486-5p showed 85% sensitivity and 70.8% specificity for men, and 70.0% sensitivity and 72.7% specificity for women. The logistic regression model used to evaluate the association of LC with the combination of MMP-1/CD63 and miRNA-486-5p revealed that the area under the ROC curve was 0.954 (95% CI: 0.908-1.000), and the model had 89% sensitivity and 88% specificity after adjusting for age, sex and smoking status. These data suggested that the combined analysis of MMP-1/CD63 and miRNA-486-5p in urinary exosomes may be used to detect patients with early-stage LC in the work-place and at community health centers, although confirmational studies are warranted.

Association of microRNA-21 expression with breast cancer subtypes and its potential as an early biomarker

Breast cancer has become the most diagnosed cancer worldwide in 2020 with high morbidity and mortality rates. The alarming increase in breast cancer incidence has sprung many researchers to focus on developing novel screening tests to identify early breast cancer which will allow clinicians to provide timely and effective treatments. With much evidence supporting the notion that the deregulation of miRNAs (a class of non-coding RNA) greatly contributes to cancer initiation and progression, the promising role of miRNAs as cancer biomarkers is gaining traction in the research world. Among the upregulated miRNAs identified in breast carcinogenesis, miR-21 was shown to be significantly expressed in breast cancer tissues and bodily fluids of breast cancer patients. Therein, this review paper aims to provide an overview of breast cancer, the role and significance of miR-21 in breast cancer pathogenesis, and its potential as a breast cancer biomarker. The paper also discusses the current types of tumor biomarkers and their limitations, the presence of miR-21 in extracellular vesicles and plasma, screening methods available for miRNA detection along with some challenges faced in developing diagnostic miR-21 testing for breast cancer to provide readers with a comprehensive outlook based on using miR-21 in clinical settings.

Exosomes: Toward a potential application in bladder cancer diagnosis and treatment

Bladder cancer (BC) is a prevalent malignant tumor of the urinary system, known for its rapid progression and high likelihood of recurrence. Despite ongoing efforts, clinical diagnosis and treatment of BC remain limited. As such, there is an urgent need to investigate potential mechanisms underlying this disease. Exosomes, which contain a variety of bioactive molecules such as nucleic acids, proteins, and lipids, are regarded as extracellular messengers because they are implicated in facilitating intercellular communication in various diseases and are pivotal in tumor advancement, serving as a promising avenue for such researches. Nevertheless, the heterogeneous nature of BC necessitates further exploration of the potential involvement of exosomes in disease progression. This review comprehensively outlines the biological attributes of exosomes and their critical roles in tumorigenesis, while also discussing their potential applications in regulating the progression of BC involving clinical diagnosis, prognostication and treatment.

Influence of the Anesthetic Technique on Circulating Extracellular Vesicles in Bladder Cancer Patients Undergoing Radical Cystectomy: A Prospective, Randomized Trial

Anesthetics have been shown to alter tumor progression and seem to influence surgical cancer outcome. Circulating extracellular vesicles as mediators of intercellular communication are involved in cancer progression and may be influenced by anesthetics. In this prospective, randomized study, effects of anesthetics on extracellular vesicles and associated micro-RNAs in bladder cancer patients undergoing radical cystectomy were tested. Extracellular vesicles from 51 patients at four perioperative time points receiving Propofol or Sevoflurane were extracted with polymer-based methods and quantified with a nanoparticle-tracking analysis. Vesicle-associated micro-RNAs were analyzed with a real-time polymerase chain reaction using array cards and single assays for tumor-associated miR-21-5p, miR-15a-5p, miR-17-5p and miR-451a. Plasma extracellular vesicle concentration (suture: fold change (fc) in Propofol at 4.1 ± 3.9 vs. Sevoflurane at 0.8 ± 0.5; p = 0.003) and associated miRNAs increased significantly (+30% post induction, +9% 30 Min surgery) in the Propofol group. Tumor-associated miRNAs increased during surgery in both groups (fc in miR-21-5p: 24.3 ± 10.2, p = 0.029; fc in miR-15a-5p: 9.7 ± 3.8, p = 0.027; fc in miR-17-5p: 5.4 ± 1.7, p = 0.014), whereas antitumor miR-451a increased in the Propofol group only (fc: 2.5 ± 0.6 vs. 1.0 ± 0.2; p = 0.022). Anesthetics influence extracellular vesicles and associated micro-RNAs of bladder cancer patients during surgery. Increased expression of antitumor micro-RNA may be an explanatory approach for decreased tumor cell viability after Propofol.

Liquid biopsy in urothelial carcinoma: Detection techniques and clinical applications

The types of urothelial carcinoma (UC) include urothelial bladder cancer and upper tract urothelial carcinoma. Current diagnostic techniques cannot meet the needs of patients. Liquid biopsy is an accurate method of determining the molecular profile of UC and is a cutting-edge and popular technique that is expected to complement existing detection techniques and benefit patients with UC. Circulating tumor cells, cell-free DNA, cell-free RNA, extracellular vesicles, proteins, and metabolites can be found in the blood, urine, or other bodily fluids and are examined during liquid biopsies. This article focuses on the components of liquid biopsies and their clinical applications in UC. Liquid biopsies have tremendous potential in multiple aspects of precision oncology, from early diagnosis and treatment monitoring to predicting prognoses. They may therefore play an important role in the management of UC and precision medicine.

Urinary MicroRNAs as Biomarkers of Urological Cancers: A Systematic Review

MicroRNAs (miRNAs) are emerging as biomarkers for the detection and prognosis of cancers due to their inherent stability and resilience. To summarize the evidence regarding the role of urinary miRNAs (umiRNAs) in the detection, prognosis, and therapy of genitourinary cancers, we performed a systematic review of the most important scientific databases using the following keywords: (urinary miRNA) AND (prostate cancer); (urinary miRNA) AND (bladder cancer); (urinary miRNA) AND (renal cancer); (urinary miRNA) AND (testicular cancer); (urinary miRNA) AND (urothelial cancer). Of all, 1364 articles were screened. Only original studies in the English language on human specimens were considered for inclusion in our systematic review. Thus, a convenient sample of 60 original articles was identified. UmiRNAs are up- or downregulated in prostate cancer and may serve as potential non-invasive molecular biomarkers. Several umiRNAs have been identified as diagnostic biomarkers of urothelial carcinoma and bladder cancer (BC), allowing us to discriminate malignant from nonmalignant forms of hematuria. UmiRNAs could serve as therapeutic targets or recurrence markers of non-muscle-invasive BC and could predict the aggressivity and prognosis of muscle-invasive BC. In renal cell carcinoma, miRNAs have been identified as predictors of tumor detection, aggressiveness, and progression to metastasis. UmiRNAs could play an important role in the diagnosis, prognosis, and therapy of urological cancers.

Role of microRNA carried by small extracellular vesicles in urological tumors

Small extracellular vesicles (sEVs) are minute vesicles secreted by various cells that are capable of transporting cargo, including microRNAs, between donor and recipient cells. MicroRNAs (miRNAs), small non-coding RNAs approximately 22 nucleotides in length, have been implicated in a wide array of biological processes, including those involved in tumorigenesis. Emerging evidence highlights the pivotal role of miRNAs encapsulated in sEVs in both the diagnosis and treatment of urological tumors, with potential implications in epithelial-mesenchymal transition, proliferation, metastasis, angiogenesis, tumor microenvironment and drug resistance. This review provides a brief overview of the biogenesis and functional mechanisms of sEVs and miRNAs, followed by a summarization of recent empirical findings on miRNAs encapsulated in sEVs from three archetypal urologic malignancies: prostate cancer, clear cell renal cell carcinoma, and bladder cancer. We conclude by underscoring the potential of sEV-enclosed miRNAs as both biomarkers and therapeutic targets, with a particular focus on their detection and analysis in biological fluids such as urine, plasma, and serum.

Extracellular Vesicles as Potential Bladder Cancer Biomarkers: Take It or Leave It?

Bladder cancer (BC) is the 10th most frequently diagnosed cancer worldwide. Although urine cytology and cystoscopy are current standards for BC diagnosis, both have limited sensitivity to detect low-grade and small tumors. Moreover, effective prognostic biomarkers are lacking. Extracellular vesicles (EVs) are lipidic particles that contain nucleic acids, proteins, and metabolites, which are released by cells into the extracellular space, being crucial effectors in intercellular communication. These particles have emerged as potential tools carrying biomarkers for either diagnosis or prognosis in liquid biopsies namely urine, plasma, and serum. Herein, we review the potential of liquid biopsies EVs’ cargo as BC diagnosis and prognosis biomarkers. Additionally, we address the emerging advantages and downsides of using EVs within this framework.

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.

Extracellular vesicles: A dive into their role in the tumor microenvironment and cancer progression

Extracellular vesicles (EVs) encompass a diverse set of membrane-derived particles released from cells and are found in numerous biological matrices and the extracellular space. Specific classes of EVs include apoptotic bodies, exosomes, and microvesicles, which vary in their size, origin, membrane protein expression, and interior cargo. EVs provide a mechanism for shuttling cargo between cells, which can influence cell physiology by transporting proteins, DNA, and RNA. EVs are an abundant component of the tumor microenvironment (TME) and are proposed to drive tumor growth and progression by communicating between fibroblasts, macrophages, and tumor cells in the TME. The cargo, source, and type of EV influences the pro- or anti-tumoral role of these molecules. Therefore, robust EV isolation and characterization techniques are required to ensure accurate elucidation of their association with disease. Here, we summarize different EV subclasses, methods for EV isolation and characterization, and a selection of current clinical trials studying EVs. We also review key studies exploring the role and impact of EVs in the TME, including how EVs mediate intercellular communication, drive cancer progression, and remodel the TME.

Urine exosomes as biomarkers in bladder cancer diagnosis and prognosis: From functional roles to clinical significance

Bladder cancer is one of the top ten most common cancers and top ten causes of cancer death globally. 5-year survival rates have decreased in Australia from 66% to 55% in the past three decades. The current gold standard for diagnosis is cystoscopy. However, cystoscopies are an invasive and health-resource intensive procedure which has sub-optimal sensitivity for flat lesions such as CIS (carcinoma in situ) and low specificity for differentiating inflammation from cancer - hence requiring biopsies under anesthesia. Frequent and life-long surveillance cystoscopy is required for most patients since there are high rates of progression and local recurrence in high-risk non-muscle invasive cancer (NMIBC) as well as poor outcomes associated with delayed detection of muscle-invasive bladder cancer (MIBC). There is an unmet need for a non-invasive test to provide better discrimination and risk-stratification of bladder cancer which could aid clinicians by improving patient selection for cystoscopy; enhanced risk stratification methods may guide the frequency of surveillance cystoscopies and inform treatment choices. Exosomes, which are nano-sized extracellular vesicles containing genetic material and proteins, have been shown to have functional roles in the development and progression of bladder cancer. Exosomes have also been demonstrated to be a robust source of potential biomarkers for bladder cancer diagnosis and prognosis and may also have roles as therapeutic agents. In this review, we summarize the latest evidence of biological roles of exosomes in bladder cancer and highlight their clinical significance in bladder cancer diagnosis, surveillance and treatment.

Emerging role of extracellular vesicles in kidney diseases

Many types of renal disease eventually progress to end-stage renal disease, which can only be maintained by renal replacement therapy. Therefore, kidney diseases now contribute significantly to the health care burden in many countries. Many new advances and strategies have been found in the research involving kidney diseases; however, there is still no efficient treatment. Extracellular vesicles (EVs) are cell-derived membrane structures, which contains proteins, lipids, and nucleic acids. After internalization by downstream cells, these components can still maintain functional activity and regulate the phenotype of downstream cells. EVs drive the information exchange between cells and tissues. Majority of the cells can produce EVs; however, its production, contents, and transportation may be affected by various factors. EVs have been proved to play an important role in the occurrence, development, and treatment of renal diseases. However, the mechanism and potential applications of EVs in kidney diseases remain unclear. This review summarizes the latest research of EVs in renal diseases, and provides new therapeutic targets and strategies for renal diseases.

Recommendations for extracellular vesicle miRNA biomarker research in the endometrial cancer context

Endometrial cancer (EC) is the most common gynaecological malignancy in the developed world, and concerningly incidence is rising, particularly in younger people. Therefore, there is increased interest in novel diagnostic and prognostic biomarkers. Extracellular vesicles (EVs) are membrane-bound particles present in bodily fluids that have the potential to facilitate non-invasive, early diagnosis of EC and could aid with monitoring of recurrence and treatment response. EV cargo provides molecular insight into the tumor, with the lipid bilayer providing stability for RNA species usually prone to degradation. miRNAs have recently become a focus for EV biomarker research due to their ability to regulate cancer related pathways and influence cancer development and progression. This review evaluates the current literature on EV miRNA biomarkers with a focus on EC, and discusses the challenges facing this research. This review finally highlights areas of focus for EV miRNA biomarker research going forward, such as standardization of normalization approaches, sample storage and processing, extensive reporting of methodologies and moving away from single miRNA biomarkers.

Diagnostic Potential of Circulating Tumor Cells, Urinary MicroRNA, and Urinary Cell-Free DNA for Bladder Cancer: A Review

Early detection of primary bladder cancer (BCa) is vital, because stage and grade have been generally accepted not only as categorical but also as prognostic factors in patients with BCa. The widely accepted screening methods for BCa, cystoscopy and urine cytology, have unsatisfactory diagnostic accuracy, with high rates of false negatives, especially for flat-type BCa with cystoscopy and for low-risk disease with urine cytology. Currently, liquid biopsy has attracted much attention as being compensatory for that limited diagnostic power. In this review, we survey the literature on liquid biopsy for the detection of BCa, focusing on circulating tumor cells (CTCs), urinary cell-free DNA (ucfDNA), and urinary microRNA (umiRNA). In diagnostic terms, CTCs and umiRNA are determined by quantitative analysis, and ucfDNA relies on finding genetic and epigenetic changes. The ideal biomarkers should be highly sensitive in detecting BCa. Currently, CTCs produce an unfavorable result; however, umiRNA and ucfDNA, especially when analyzed using a panel of genes, produce promising results. However, given the small cohort size in most studies, no conclusions can yet be drawn about liquid biopsy's immediate application to clinical practice. Further large studies to validate the diagnostic value of liquid biopsy for clinical use are mandatory.

The Role of Novel Bladder Cancer Diagnostic and Surveillance Biomarkers-What Should a Urologist Really Know?

The aim of this review is to analyze and describe the current landscape of bladder cancer diagnostic and surveillance biomarkers. We researched the literature from 2016 to November 2021 to find the most promising new molecules and divided them into seven different subgroups based on their function and location in the cell. Although cystoscopy and cytology are still the gold standard for diagnosis and surveillance when it comes to bladder cancer (BCa), their cost is quite a burden for national health systems worldwide. Currently, the research is focused on finding a biomarker that has high negative predictive value (NPV) and can exclude with a certainty the presence of the tumor, considering missing it could be disastrous for the patient. Every subgroup has its own advantages and disadvantages; for example, protein biomarkers cost less than genomic ones, but on the other hand, they seem to be less precise. We tried to simplify this complicated topic as much as possible in order to make it comprehensible to doctors and urologists that are not as familiar with it, as well as encourage them to actively participate in ongoing research.

EphA2 on urinary extracellular vesicles as a novel biomarker for bladder cancer diagnosis and its effect on the invasiveness of bladder cancer

BACKGROUND

Urinary extracellular vesicles (uEVs) secreted from bladder cancer contain cancer-specific proteins that are potential diagnostic biomarkers. We identified and evaluated a uEV-based protein biomarker for bladder cancer diagnosis and analysed its functions.

METHODS

Biomarker candidates, selected by shotgun proteomics, were validated using targeted proteomics of uEVs obtained from 49 patients with and 48 individuals without bladder cancer, including patients with non-malignant haematuria. We developed an enzyme-linked immunosorbent assay (ELISA) for quantifying the uEV protein biomarker without ultracentrifugation and evaluated urine samples from 36 patients with and 36 patients without bladder cancer.

RESULTS

Thirteen membrane proteins were significantly upregulated in the uEVs from patients with bladder cancer in shotgun proteomics. Among them, eight proteins were validated by target proteomics, and Ephrin type-A receptor 2 (EphA2) was the only protein significantly upregulated in the uEVs of patients with bladder cancer, compared with that of patients with non-malignant haematuria. The EV-EphA2-CD9 ELISA demonstrated good diagnostic performance (sensitivity: 61.1%, specificity: 97.2%). We showed that EphA2 promotes proliferation, invasion and migration and EV-EphA2 promotes the invasion and migration of bladder cancer cells.

CONCLUSIONS

We established EV-EphA2-CD9 ELISA for uEV-EphA2 detection for the non-invasive early clinical diagnosis of bladder cancer.

Cancer-Derived Extracellular Vesicles: Their Role in Sarcoma

Soft tissue sarcomas (STS) are rare malignancies with limited responses to anticancer therapy. Extracellular vesicles (EVs) are a heterogeneous group of bi-lipid layer sacs secreted by cells into extracellular space. Investigations of tumor-derived EVs have revealed their functional capabilities, including cell-to-cell communication and their impact on tumorigenesis, progression, and metastasis; however information on the roles of EVs in sarcoma is currently limited. In this review we investigate the role of various EV cargos in sarcoma and the mechanisms by which those cargos can affect the recipient cell phenotype and the aggressivity of the tumor itself. The study of EVs in sarcoma may help establish novel therapeutic approaches that target specific sarcoma subtypes or biologies, thereby improving sarcoma therapeutics in the future.

Molecular profiles and urinary biomarkers of upper tract urothelial carcinomas associated with aristolochic acid exposure

Recurrent upper tract urothelial carcinomas (UTUCs) arise in the context of nephropathy linked to exposure to the herbal carcinogen aristolochic acid (AA). Here we delineated the molecular programs underlying UTUC tumorigenesis in patients from endemic aristolochic acid nephropathy (AAN) regions in Southern Europe. We applied an integrative multiomics analysis of UTUCs, corresponding unaffected tissues and of patient urines. Quantitative microRNA (miRNA) and messenger ribonucleic acid (mRNA) expression profiling, immunohistochemical analysis by tissue microarrays and exome and transcriptome sequencing were performed in UTUC and nontumor tissues. Urinary miRNAs of cases undergoing surgery were profiled before and after tumor resection. Ribonucleic acid (RNA) and protein levels were analyzed using appropriate statistical tests and trend assessment. Dedicated bioinformatic tools were used for analysis of pathways, mutational signatures and result visualization. The results delineate UTUC-specific miRNA:mRNA networks comprising 89 miRNAs associated with 1,862 target mRNAs, involving deregulation of cell cycle, deoxyribonucleic acid (DNA) damage response, DNA repair, bladder cancer, oncogenes, tumor suppressors, chromatin structure regulators and developmental signaling pathways. Key UTUC-specific transcripts were confirmed at the protein level. Exome and transcriptome sequencing of UTUCs revealed AA-specific mutational signature SBS22, with 68% to 76% AA-specific, deleterious mutations propagated at the transcript level, a possible basis for neoantigen formation and immunotherapy targeting. We next identified a signature of UTUC-specific miRNAs consistently more abundant in the patients' urine prior to tumor resection, thereby defining biomarkers of tumor presence. The complex gene regulation programs of AAN-associated UTUC tumors involve regulatory miRNAs prospectively applicable to noninvasive urine-based screening of AAN patients for cancer presence and recurrence.

Extracellular vesicles in pharmacology: Novel approaches in diagnostics and therapy

Exosomes are nano-sized lipid vesicles that are produced by all eukaryotic cells, and they typically range in size from 30 to 150 nm. Exosomes were discovered almost 40 years ago; however, the last two decades have attracted considerable attention due to exosomes' inherent abilities to shuttle nucleic acids, lipids and proteins between cells, along with their natural affinity to exosome target cells. From a pharmaceutical perspective, exosomes are regarded as naturally produced nanoparticle drug delivery vehicles. The application of exosomes as a means of drug delivery offers critical advantages compared to other nanoparticulate drug delivery systems, such as liposomes and polymeric nanoparticles. These advantages are due to the exosomes' intrinsic features, such as low immunogenicity, biocompatibility, stability, and their ability to overcome biological barriers. Herein, we outline the structure and origin of exosomes, as well as their biological functions. We also touch upon recent advances in exosome labeling, imaging and drug loading. Finally, we discuss exosomes in targeted drug delivery and clinical trial development.

MicroRNA as a Biomarker for Diagnostic, Prognostic, and Therapeutic Purpose in Urinary Tract Cancer

The incidence of urologic cancers, including kidney, upper tract urothelial, and bladder malignancies, is increasing globally, with a high percentage of cases showing metastasis upon diagnosis and low five-year survival rates. MicroRNA (miRNA), a small non-coding RNA, was found to regulate the expression of oncogenes and tumor suppressor genes in several tumors, including cancers of the urinary system. In the current review, we comprehensively discuss the recently reported up-or down-regulated miRNAs as well as their possible targets and regulated pathways involved in the development, progression, and metastasis of urinary tract cancers. These miRNAs represent potential therapeutic targets and diagnostic/prognostic biomarkers that may help in efficient and early diagnosis in addition to better treatment outcomes.

Meta-analysis of the diagnostic value of exosomal miR-21 as a biomarker for the prediction of cancer

BACKGROUND

Early diagnosis of cancer is still the most effective method to increase survival and therapeutically effective patient management. Accumulating studies had exploited exosomes as an indicator for the diagnosis and prognosis of cancer. In addition to exosomes, exosome-derived miRs are widely investigated as a novel biomarker for diagnosis in cancer patients. The aim of this study was to clarify the diagnostic value of ex-miR-21 in cancer.

METHODS

Databases were searched for eligible studies up to June, 2021. Studies included in this meta-analysis were reviewed and selected independently by two authors. The data of sensitivity, specificity, diagnostic odds ratio (DOR), and summary receiver operating characteristic curves (SROC) of exosomal miR-21 as a diagnostic biomarker were extracted and calculated. Quality assessment was conducted by using the QUADAS-2 tool.

RESULTS

A total of 26 studies were included in the systematic analysis and meta-analysis. The pooled results of sensitivity, specificity, PLR/NLR, DOR, and area under the curve were 76% (95%CI, 0.70-0.81), 82% (0.77-0.87), 4.3 (3.1-6.0), 0.29 (0.22-0.38), 15 (8-26), and 0.86 (0.83-0.89), respectively. Sensitivity analysis and Deeks' funnel plot indicated that results remained unchanged and had no publication bias. For the subgroup analysis, it was showed that ex-miR-21 had a superior diagnostic accuracy on identifying PC.

CONCLUSION

Exosomal microRNA-21 can serve as an effective and widely used diagnostic biomarker for cancer, especially in PC. The using field of exosomes and exosome-derived miR can further extend the prognosis and therapeutic management. Standardized isolation of exosomes and miRNA-21 should be developed.

Urinary Exosomes Diagnosis of Urological Tumors: A Systematic Review and Meta-Analysis

Purpose

Exosomes could be released directly into the urine by the urological tumoral cells, so testing urinary exosomes has great potential for non-invasive diagnosis and monitor of urological tumors. The objective of this study is to systematically review and meta-analysis of urinary exosome for urological tumors diagnosis.

Materials and Methods

A systematic review of the recent English-language literature was conducted according to the PRISMA statement recommendations (CRD42021250613) using PubMed, Embase, Cochrane Library, Web of Science, and Scopus databases up to April 30, 2021. Risk-of-bias assessment was performed according to the QUADAS 2 tool. The true diagnostic value of urinary exosomes by calculating the number of true positive, false positive, true negative, and false negative, diagnoses by extracting specificity and sensitivity data from the selected literature.

Results

Sixteen eligible studies enrolling 3224 patients were identified. The pooled sensitivity and specificity of urinary exosomes as a diagnostic tool in urological tumors were 83% and 88%, respectively. The area under the summary receiver operating characteristic curve was 0.92 (95% CI: 0.89–0.94). Further subgroup analyses showed that our results were stable irrespective of the urinary exosome content type and tumor type.

Conclusion

Urinary exosomes may serve as novel non-invasive biomarkers for urological cancer detection. Future clinical trial designs must validate and explore their utility in treatment decision-making.

Systematic Review Registration

[ https://www.crd.york.ac.uk/prospero/], identifier [CRD42021250613].

Extracellular Vesicles: New Tools for Early Diagnosis of Breast and Genitourinary Cancers

Breast cancers and cancers of the genitourinary tract are the most common malignancies among men and women and are still characterized by high mortality rates. In order to improve the outcomes, early diagnosis is crucial, ideally by applying non-invasive and specific biomarkers. A key role in this field is played by extracellular vesicles (EVs), lipid bilayer-delimited structures shed from the surface of almost all cell types, including cancer cells. Subcellular structures contained in EVs such as nucleic acids, proteins, and lipids can be isolated and exploited as biomarkers, since they directly stem from parental cells. Furthermore, it is becoming even more evident that different body fluids can also serve as sources of EVs for diagnostic purposes. In this review, EV isolation and characterization methods are described. Moreover, the potential contribution of EV cargo for diagnostic discovery purposes is described for each tumor.

Extracellular vesicles in urological malignancies

Extracellular vesicles (EVs) are small lipid bound structures released from cells containing bioactive cargoes. Both the type of cargo and amount loaded varies compared to that of the parent cell. The characterisation of EVs in cancers of the male urogenital tract has identified several cargoes with promising diagnostic and disease monitoring potential. EVs released by cancers of the male urogenital tract promote cell-to-cell communication, migration, cancer progression and manipulate the immune system promoting metastasis by evading the immune response. Their use as diagnostic biomarkers represents a new area of screening and disease detection, potentially reducing the need for invasive biopsies. Many validated EV cargoes have been found to have superior sensitivity and specificity than current diagnostic tools currently in use. The use of EVs to improve disease monitoring and develop novel therapeutics will enable clinicians to individualise patient management in the exciting era of personalised medicine.

Effect of miRNA-136-targeted regulation of FGFR1 on proliferation and apoptosis of triple-negative breast cancer cells

PURPOSE

This study was designed to investigate the effect of micro RNA-targeted regulation of FGFR1 on the proliferation and apoptosis of triple-negative breast cancer (TNBC) cells.

METHODS

TNBC (MAD-MB-231), three types of breast cancer (MCF10A, MCF7, ZR751) cell lines, and normal breast tissue cell lines were extracted. Real-time PCR was used to detect the expression of miRNA-136 in different types of breast cells. The MAD-MB-231 cell lines were transfected with miRNA-136 mimic by lipofection. The effects of miRNA-136 on FGFR1 expression and apoptosis rate of MAD-MB-231 cell lines were determined using western blotting.

RESULTS

miRNA-136 expression in TNBC cells was lower than that of controls, and was negatively correlated with TNM staging. miRNA-136 expression in MCF10A, MCF7, ZR751, and MAD-MB-231 cell lines was gradually decreased, and MCF10A expression in the other three cell lines was significantly higher than that of MAD-MB-231 cell line (P<0.05). Transfection with miRNA-136 significantly reduced the proliferation rate of MAD-MB-231, and a higher concentration and longer duration exhibited a more pronounced inhibitory effect on proliferation (P<0.05). Transfection with miRNA-136 significantly reduced FGFR1 expression in the MAD-MB-231 cell lines, without significantly affecting apoptosis.

CONCLUSION

miRNA-136 shows a very low expression level in TNBC cells. Transfection with miRNA-136 can significantly inhibit the proliferation of TNBC cells by external transfection, and has little effect on cell apoptosis. This may be related to miRNA-mediated changes in FGFR1 protein expression.

Urinary exosomal microRNA-96-5p and microRNA-183-5p expression as potential biomarkers of bladder cancer

Because of low sensitivity and specificity of the currently available urine biomarkers of bladder cancer (BC) detection and painful cystoscopy procedure. Our study aimed to evaluate expression of urinary exosomal miR-96-5p and miR-183-5p as probable non-invasive and accurate biomarkers for the diagnosis and follow up of BC. Using quantitative real-time polymerase chain reaction; expression of exosomal microRNA (miR)-96-5p and miR- 183-5p in the urine samples of 51 patients with BC, 21 patients with benign urinary bladder lesions and in 24 normal individuals as control group was done. Our study results showed higher expressions of both miR-96-5p and miR-183-5p in urine of BC patients in comparison with control group (P < 0.001 for each). Receiver operating characteristic curve (ROC) analysis showed that each microRNA had good sensitivity and specificity to differentiate BC from non-BC patients miR-96-5p 80.4% and 91.8% and miR-183-5p 78.4% and 81.6% respectively compared to cytology (37.3% and 100%). In addition, it was obvious that the sensitivity of combined miR-96-5p and miR-183-5p for the diagnosis of BC reached 88.2%% and specificity reached 87.8%, which were higher than each one alone. We also found that expression of miR-96-5p and miR-183-5p with high grade, and pathological stage was significantly increased. After surgery, collected urine samples showed significantly lower expression of miR-96-5p-: P < 0.001; and miR-183-5p: P = 0.002. In conclusion, urine miR-96-5p and miR-183-5p are promising tumor biomarkers of BC diagnosis; particularly, when they combined with each other or with urinary cytology.

Differentially Expressed Extracellular Vesicle-Contained microRNAs before and after Transurethral Resection of Bladder Tumors

Bladder cancer (BC) is currently diagnosed and monitored by cystoscopy, a costly and invasive procedure. Potential biomarkers in urine, blood, and, more recently, extracellular vesicles (EVs), have been explored as non-invasive alternatives for diagnosis and surveillance of BC. EVs are nanovesicles secreted by most cell types containing diverse molecular cargo, including different types of small RNAs, such as microRNA (miRNA). In this study, we performed next-generation sequencing of EV-contained miRNA isolated from urine and serum of 41 patients with non-muscle invasive BC (27 stage Ta, 14 stage T1) and 15 non-cancer patients (NCP) with benign cystoscopy findings. MiRNA sequencing was also performed on serum supernatant samples for T1 patients. To identify potential BC-specific biomarkers, expression levels of miRNA in presurgery samples were compared to those at postsurgery check-ups, and to NCPs. Results showed that two miRNAs, urinary EV-contained miR-451a and miR-486-5p, were significantly upregulated in presurgery samples from T1 patients compared to postsurgery check-up samples. This was confirmed in a replica EV/RNA isolation and sequencing run of 10 T1 patients from the primary run; however, analyses revealed no differential expression of miRNAs in serum EVs, serum supernatant, or when comparing BC patients to NCPs. This is the first study to investigate EV-containing miRNA sequencing in pre- and postsurgery BC patient samples and our findings suggest that urinary EV-contained miR-451a and miR-486-5p may be potential biomarkers for recurrence-free survival of BC patients with stage T1 disease.

Proteomic analysis of urinary and tissue-exudative extracellular vesicles to discover novel bladder cancer biomarkers

Proteomic analysis of urinary extracellular vesicles (EVs) is a powerful approach to discover potential bladder cancer (BCa) biomarkers, however urine contains numerous EVs derived from the kidney and normal urothelial epithelium, which can obfuscate information related to BCa cell-derived EVs. In this study, we combined proteomic analysis of urinary EVs and tissue-exudative EVs (Te-EVs), which were isolated from culture medium of freshly resected viable BCa tissues. Urinary EVs were isolated from urine samples of 11 individuals (7 BCa patients and 4 healthy individuals), and Te-EVs were isolated from 7 BCa tissues. We performed tandem mass tag (TMT)-labeling liquid chromatography (LC-MS/MS) analysis for both urinary EVs and Te-EVs and identified 1960 proteins in urinary EVs and 1538 proteins in Te-EVs. Most of the proteins identified in Te-EVs were also present in urinary EVs (82.4%), with 55 of these proteins showing upregulated levels in the urine of BCa patients (fold change > 2.0; P < .1). Among them, we selected 22 membrane proteins as BCa biomarker candidates for validation using selected reaction monitoring/multiple reaction monitoring (SRM/MRM) analysis on urine samples from 70 individuals (40 BCa patients and 30 healthy individuals). Six urinary EV proteins (heat-shock protein 90, syndecan-1, myristoylated alanine-rich C-kinase substrate (MARCKS), MARCKS-related protein, tight junction protein ZO-2, and complement decay-accelerating factor) were quantified using SRM/MRM analysis and validated as significantly upregulated in BCa patients (P < .05). In conclusion, the novel strategy that combined proteomic analysis of urinary EVs and Te-EVs enabled selective detection of urinary BCa biomarkers.

Combination of Urine Exosomal mRNAs and lncRNAs as Novel Diagnostic Biomarkers for Bladder Cancer

Background

The recent discovery of miRNAs and lncRNAs in urine exosomes has emerged as promising diagnostic biomarkers for bladder cancer (BCa). However, mRNAs as the direct products of transcription has not been well evaluated in exosomes as biomarkers for BCa diagnosis. The purpose of this study was to identify tumor progression-related mRNAs and lncRNAs in urine exosomes that could be used for detection of BCa.

Methods

RNA-sequencing was performed to identify tumor progression-related biomarkers in three matched superficial tumor and deep infiltrating tumor regions of muscle-invasive bladder cancer (MIBC) specimens, differently expressed mRNAs and lncRNAs were validated in TCGA dataset (n = 391) in the discovery stage. Then candidate RNAs were chosen for evaluation in urine exosomes of a training cohort (10 BCa and 10 healthy controls) and a validation cohort (80 BCa and 80 healthy controls) using RT-qPCR. The diagnostic potential of the candidates were evaluated by receiver operating characteristic (ROC) curves.

Results

RNA sequencing revealed 8 mRNAs and 32 lncRNAs that were significantly upregulated in deep infiltrating tumor region. After validation in TCGA database, 10 markedly dysregulated RNAs were selected for further investigation in urine exosomes, of which five (mRNAs: KLHDC7B, CASP14, and PRSS1; lncRNAs: MIR205HG and GAS5) were verified to be significantly dysregulated. The combination of the five RNAs had the highest AUC to disguising the BCa (0.924, 95% CI, 0.875–0.974) or early stage BCa patients (0.910, 95% CI, 0.850 to 0.971) from HCs. The expression levels of these five RNAs were correlated with tumor stage, grade, and hematuria degrees.

Conclusions

These findings highlight the potential of urine exosomal mRNAs and lncRNAs profiling in the early diagnosis and provide new insights into the molecular mechanisms involved in BCa.

Urinary extracellular vesicles: a rising star in bladder cancer management

Clinically, the detection of bladder cancer (BCa) typically requires cystoscopy, which is potentially harmful and sometimes accompanied by adverse effects. Thus, new biomarkers are desirable for improving the management of BCa. Recently, “liquid biopsy” has received enormous attentions and has been extensively studied due to its promising clinical implication for precise medicine. Especially, extracellular vesicles (EVs) have attracted strong interest as a potential source of biomarkers. EVs have been reported to be found in almost all types of body fluids and are easy to collect. In addition, EVs tightly reflect the current state of the disease by inheriting specific biomolecules from their parental cells. Urinary EVs have gained great scientific interest in the field of BCa biomarker research since urine is in direct contact with BCa and can contain large amounts of EVs from the tumour microenvironment. To date, various kinds of biomolecules, including noncoding RNAs, mRNAs, and proteins, have been investigated as biomarkers in urinary EVs. In this narrative review, we summarize the recent advances regarding urinary EVs as non-invasive biomarkers in patients with BCa. The current hurdles in the clinical implications of EV-based liquid biopsy and the potential applications of EV research are also discussed.

MiR-30b-3p and miR-126-3p of urinary extracellular vesicles could be new biomarkers for prostate cancer

Background

Extracellular vesicles (EVs) including exosomes are present in blood, urine, and saliva and contain proteins, microRNAs, and messenger RNAs. We investigated microRNAs in urinary EVs to discover new biomarkers of prostate cancer (PCa).

Methods

We isolated EVs from urine obtained following digital rectal examination (DRE) of 14 men with elevated levels of serum prostate-specific antigen (PSA) [negative biopsy (n=4) and PCa with Gleason scores of 6 (n=3), 7 (n=3), and 8-9 (n=4)]. MicroRNAs extracted from EVs were analyzed by microRNA microarray.

Results

MicroRNAs miR-30b-3p and miR-126-3p were identified as being overexpressed in urinary EVs of the PCa patients versus the biopsy-negative men, but no microRNAs were associated with the Gleason score. In the independent cohort as well, these two microRNAs were overexpressed in urinary EVs from the PCa patients versus the negative-biopsy men. Logistic regression analysis adjusted by age and PSA showed that these two microRNAs were significantly associated with the prediction of PCa in biopsy specimens. Sensitivity and specificity of miR-30b-3p and miR-126-3p for the prediction of PCa were 46.4% and 88.0% and 60.7% and 80.0%, respectively, which were better than those of serum PSA (53.5% and 64.0%, respectively).

Conclusions

MiR-30b-3p and miR-126-3p in urinary EVs could be potential biomarkers of PCa.

Urinary Extracellular Vesicles as Potential Biomarkers for Urologic Cancers: An Overview of Current Methods and Advances

Urologic cancers are a heterogeneous group of tumors, some of which have poor prognosis. This is partly due to the unavailability of specific and sensitive diagnostic techniques and monitoring tests, ideally non- or minimally invasive. Hence, liquid biopsies are promising tools that have been gaining significant attention over the last decade. Among the different classes of biomarkers that can be isolated from biofluids, urinary extracellular vesicles (uEVs) are a promising low-invasive source of biomarkers, with the potential to improve cancer diagnosis and disease management. Different techniques have been developed to isolate and characterize the cargo of these vesicles; however, no consensus has been reached, challenging the comparison among studies. This results in a vast number of studies portraying an extensive list of uEV-derived candidate biomarkers for urologic cancers, with the potential to improve clinical outcome; however, without significant validation. Herein, we review the current published research on miRNA and protein-derived uEV for prostate, bladder and kidney cancers, focusing on different uEV isolation methods, and its implications for biomarker studies.

Extracellular Vesicles as Biomarkers Carriers in Bladder Cancer: Diagnosis, Surveillance, and Treatment

Exosomes are extracellular vesicles, enriched in biomolecular cargo consisting of nucleic acids, proteins, and lipids, which take part in intercellular communication and play a crucial role in both physiologic functions and oncogenesis. Bladder cancer is the most common urinary malignancy and its incidence is steadily rising in developed countries. Despite the high five-year survival in patients diagnosed at early disease stage, survival substantially drops in patients with muscle-invasive or metastatic disease. Therefore, early detection of primary disease as well as recurrence is of paramount importance. The role that exosomal biomarkers could play in bladder cancer patient diagnosis and surveillance, as well as their potential therapeutic applications, has not been extensively studied in this malignancy. In the present review, we summarize all relevant data obtained so far from cell lines, animal models, and patient biofluids and tissues. Current literature suggests that urine is a rich source of extracellular vesicle-derived biomarkers, compared with blood and bladder tissue samples, with potential applications in bladder cancer management. Further studies improving sample collection procedures and optimizing purification and analytical methods should augment bladder cancer diagnostic, prognostic, and therapeutic input of extracellular vesicles biomarkers in the future.

Exosomal microRNA panels as biomarkers for hematological malignancies

Hematological malignancies are classified as a heterogeneous category of cancers with various degrees of incidence and prognosis and different etiologies. Due to their aggressive essence they should be diagnosed as early as possible to improve prognosis, treatment outcome and survival. Bases on the limitations of previously identified biomarkers in terms of sensitivity, specificity and predictability, it is necessary to develop new diagnostic tools and biomarkers for the early diagnosis of hematological malignancies. Exosomes are nanovesicles secreted by almost all cell types in both physiological and pathological conditions. They play major roles in intercellular communication and are recently being considered as disease biomarkers. These nanovesicles carry proteins, lipids and nucleic acids like microRNAs (miRNAs). miRNAs are small noncoding RNAs, which act as translational suppressors via regulating protein-coding genes. The aberrant expression of miRNAs has been shown in various conditions including hematological malignancies. Moreover, it is now known that tumor cells secrete higher amounts of exosomes compared to normal cells. The idea of using exosomal miRNAs in serum as biomarkers is based on their surprisingly high stability and specificity. In the present paper, we reviewed and recommended exosomal miRNA panels including (miR-150, miR-155 and miR-1246), (miR-17-5p, miR-20a-5p, miR-16-5p and miR-5a-5p), (miR-18a, Let-7b) and (miR192-5p, miR21-5p, miR320b and Let-7d), for their potential to be used as non-invasive biomarkers in different hematological malignancies such as multiple myeloma, leukemia, and lymphoma.

Role of Exosomal miRNA in Bladder Cancer: A Promising Liquid Biopsy Biomarker

Bladder cancer (BCa) is the most prevalent neoplasia of the urinary tract. Unfortunately, limited improvements in effective BCa management have meant that it remains a challenging disease. Cystoscopy has been the gold standard for BCa diagnosis and surveillance for over two centuries but is an invasive and expensive approach. Recently, liquid biopsy has been identified as a promising field of cancer research, due to its noninvasiveness and ease of sampling. Liquid biopsy samples could provide comprehensive information regarding the genetic landscape of cancer and could track genomic evolution of the disease over time. Exosomes, which contain RNAs, DNAs, and proteins, are a potential source of tumor biomarkers in liquid biopsy samples. In particular, exosomal miRNAs (exomiRs) hold great promise as biomarkers for tumor development and progression. In this review, we provide an overview of liquid biopsy biomarkers, with a particular focus on the use of exomiRs as biomarkers of cancer, and summarize their clinical implications for BCa. Finally, we discuss the future perspectives of these biomarkers in cancer research.

Urinary Extracellular Vesicles: Ultracentrifugation Method

Recently, urinary extracellular vesicles (EVs) have garnered interest as a potential source of noninvasive biomarkers of diseases related to urinary organs (kidney, bladder, urethra, and prostate).Ultracentrifugation is considered the gold standard method for isolation of EVs. However, the precipitates after ultracentrifugation steps are usually contaminated with soluble proteins, such as the Tamm-Horsfall protein (uromodulin).Therefore, ultracentrifugation on a sucrose-deuterium oxide (D₂O) cushion for purer EV isolation is performed to remove these proteins. In addition, as a nonultracentrifugation method for EV isolation, we have also adopted the phosphatidylserine (PS) affinity method, which is a novel method for EV purification using the T-cell immunoglobulin domain and the mucin domain-containing protein 4 (Tim4).Here, we describe an ultracentrifugation protocol based on a sucrose-D₂O cushion and the PS affinity method protocol for the isolation of urinary EVs.

Application of exosomes as liquid biopsy in clinical diagnosis

Liquid biopsy refers to the sampling and molecular analysis of the biofluids of circulating tumor cells, extracellular vesicles, nucleic acids, and so forth. Exosomes are small extracellular vesicles with sizes between 30–150 nm. They are secreted by multivesicular bodies through exocytosis in live cells and can participate in intercellular communication due to their contents, including nucleic acids, proteins, and lipids. Herein, we investigate publication frequencies on exosomes over the past 10 years, and review recent clinical studies on liquid biopsy of exosomes in the fields of oncology, pregnancy disorders, cardiovascular diseases, and organ transplantation. We also describe the advantages of exosomes as an effective liquid biopsy tool and the progression of exosome extraction methods. Finally, we depict the commercial development of exosome research and discuss the future role of exosomes in liquid biopsy.

MicroRNAs from Liquid Biopsy Derived Extracellular Vesicles: Recent Advances in Detection and Characterization Methods

Liquid biopsies have become a convenient tool in cancer diagnostics, real-time disease monitoring, and evaluation of residual disease. Yet, the information still encrypted in the variety of tumor-derived molecules identified in biofluids has proven difficult to decipher due to the technological limitations imposed by their biological nature. Such is the case of extracellular vesicle (EV) encapsulated ncRNAs, which have gained traction in recent years as biomarkers. Due to their resilience towards degrading factors they may act as suitable disease indicators. This review addresses the less described issues in this context. We present an overview of less investigated biofluids that can be used for EV isolation in addition to different isolation approaches to overcome the technical challenges these specimens harbor. Furthermore, we summarize the latest technological advances providing improvement to ncRNA detection and analysis. Thereby, this review summarizes the current state-of-the-art methodologies regarding EV and EV derived miRNA analysis and how they compare to current approaches.

Urine biopsy technologies: Cancer and beyond

Since the discovery of circulating tumor cells in 1869, technological advances in the study of biomarkers from liquid biopsy have made it possible to diagnose disease in a less invasive way. Although blood-based liquid biopsy has been used extensively for the detection of solid tumors and immune diseases, the potential of urine-based liquid biopsy has not been fully explored. Advancements in technologies for the harvesting and analysis of biomarkers are providing new opportunities for the characterization of other disease types. Liquid biopsy markers such as exfoliated bladder cancer cells, cell-free DNA (cfDNA), and exosomes have the potential to change the nature of disease management and care, as they allow a cost-effective and convenient mode of patient monitoring throughout treatment. In this review, we addressed the advancement of research in the field of disease detection for the key liquid biopsy markers such as cancer cells, cfDNA, and exosomes, with an emphasis on urine-based liquid biopsy. First, we highlighted key technologies that were widely available and used extensively for clinical urine sample analysis. Next, we presented recent technological developments in cell and genetic research, with implications for the detection of other types of diseases, besides cancer. We then concluded with some discussions on these areas, emphasizing the role of microfluidics and artificial intelligence in advancing point-of-care applications. We believe that the benefits of urine biopsy provide diagnostic development potential, which will pave opportunities for new ways to guide treatment selections and facilitate precision disease therapies.