Exosomal and Non-Exosomal Urinary miRNAs in Prostate Cancer Detection and Prognosis

Consensus statement on extracellular vesicles in liquid biopsy for advancing laboratory medicine

Extracellular vesicles (EVs) represent a diverse class of nanoscale membrane vesicles actively released by cells. These EVs can be further subdivided into categories like exosomes and microvesicles, based on their origins, sizes, and physical attributes. Significantly, disease-derived EVs have been detected in virtually all types of body fluids, providing a comprehensive molecular profile of their cellular origins. As a result, EVs are emerging as a valuable addition to liquid biopsy techniques. In this collective statement, the authors share their current perspectives on EV-related research and product development, with a shared commitment to translating this newfound knowledge into clinical applications for cancer and other diseases, particularly as disease biomarkers. The consensus within this document revolves around the overarching recognition of the merits, unresolved questions, and existing challenges surrounding EVs. This consensus manuscript is a collaborative effort led by the Committee of Exosomes, Society of Tumor Markers, Chinese anti-Cancer Association, aimed at expediting the cultivation of robust scientific and clinically applicable breakthroughs and propelling the field forward with greater swiftness and efficacy.

Applications of Urinary Extracellular Vesicles in the Diagnosis and Active Surveillance of Prostate Cancer

Prostate cancer is the most common non-cutaneous cancer among men in the UK, causing significant health and economic burdens. Diagnosis and risk prognostication can be challenging due to the genetic and clinical heterogeneity of prostate cancer as well as uncertainties in our knowledge of the underlying biology and natural history of disease development. Urinary extracellular vesicles (EVs) are microscopic, lipid bilayer defined particles released by cells that carry a variety of molecular cargoes including nucleic acids, proteins and other molecules. Urine is a plentiful source of prostate-derived EVs. In this narrative review, we summarise the evidence on the function of urinary EVs and their applications in the evolving field of prostate cancer diagnostics and active surveillance. EVs are implicated in the development of all hallmarks of prostate cancer, and this knowledge has been applied to the development of multiple diagnostic tests, which are largely based on RNA and miRNA. Common gene probes included in multi-probe tests include PCA3 and ERG, and the miRNAs miR-21 and miR-141. The next decade will likely bring further improvements in the diagnostic accuracy of biomarkers as well as insights into molecular biological mechanisms of action that can be translated into opportunities in precision uro-oncology.

Modulation of the pre-metastatic bone niche: molecular changes mediated by bone-homing prostate cancer extracellular vesicles

Prostate cancer (PCa) is a leading male malignancy worldwide, often progressing to bone metastasis, with limited curative options. Extracellular vesicles (EVs) have emerged as key players in cancer communication and metastasis, promoting the formation of supportive microenvironments in distant sites. Our previous studies have highlighted the role of PCa EVs in modulating osteoblasts and facilitating tumor progression. However, the early pre-metastatic changes induced by PCa EVs within the bone microenvironment remain poorly understood. To investigate the early effects of repeated exposure to PCa EVs in vivo, mimicking EVs being shed from the primary tumor, PCa EVs isolated from cell line PC3MLuc2a were fluorescently labelled and repeatedly administered via tail vein injection to adult CD1 NuNu male mice for a period of 4 weeks. In vivo imagining, histological analysis and gene expression profiling were performed to assess the impact of PCa EVs on the bone microenvironment. We demonstrate for the first time that PCa EVs home to both bone and lymph nodes following repeated exposures. Furthermore, the accumulation of EVs within the bone leads to distinct molecular changes indicative of disrupted bone homeostasis (e.g., changes to signaling pathways such as Paxillin p = 0.0163, Estrogen Receptor p = 0.0271, RHOA p = 0.0287, Ribonucleotide reductase p = 0.0307 and ERK/MAPK p = 0.0299). Changes in key regulators of these pathways were confirmed in vitro on human osteoblasts. In addition, our data compares the known gene signature of osteocytes and demonstrates a high proportion of overlap (52.2%), suggesting a potential role for this cell type in response to PCa EV exposure. No changes in bone histology or immunohistochemistry were detected, indicating that PCa EV mediated changes were induced at the molecular level. This study provides novel insights into the alterations induced by PCa EVs on the bone microenvironment. The observed molecular changes indicate changes in key pathways and suggest a role for osteocytes in these EV mediated early changes to bone. Further research to understand these early events may aid in the development of targeted interventions to disrupt the metastatic cascade in PCa.

Harnessing tumor-derived exosomes: A promising approach for the expansion of clinical diagnosis, prognosis, and therapeutic outcome of prostate cancer

Prostate cancer is the second leading cause of men's death worldwide. Although early diagnosis and therapy for localized prostate cancer have improved, the majority of men with metastatic disease die from prostate cancer annually. Therefore, identification of the cellular-molecular mechanisms underlying the progression of prostate cancer is essential for overcoming controlled proliferation, invasion, and metastasis. Exosomes are small extracellular vesicles that mediate most cells' interactions and contain membrane proteins, cytosolic and nuclear proteins, extracellular matrix proteins, lipids, metabolites, and nucleic acids. Exosomes play an essential role in paracrine pathways, potentially influencing Prostate cancer progression through a wide variety of mechanisms. In the present review, we outline and discuss recent progress in our understanding of the role of exosomes in the Prostate cancer microenvironment, like their involvement in prostate cancer occurrence, progression, angiogenesis, epithelial-mesenchymal transition, metastasis, and drug resistance. We also present the latest findings regarding the function of exosomes as biomarkers, direct therapeutic targets in prostate cancer, and the challenges and advantages associated with using exosomes as natural carriers and in exosome-based immunotherapy. These findings are a promising avenue for the expansion of potential clinical approaches.

Clinical Biofluid Assays for Prostate Cancer

This mini review summarizes the currently available clinical biofluid assays for PCa. The second most prevalent cancer worldwide is PCa. PCa is a heterogeneous disease, with a large percentage of prostate tumors being indolent, and with a relatively slow metastatic potential. However, due to the high case numbers, the absolute number of PCa-related deaths is still high. In fact, it causes the second highest number of cancer deaths in American men. As a first step for the diagnosis of PCa, the PSA test has been widely used. However, it has low specificity, which results in a high number of false positives leading to overdiagnosis and overtreatment. Newer derivatives of the original PSA test, including the Food and Drug Administration (FDA)-approved 4K (four kallikreins) and the PHI (Prostate Health Index) blood tests, have higher specificities. Tissue-based PCa tests are problematic as biopsies are invasive and have limited accuracy due to prostate tumor heterogeneity. Liquid biopsies offer a minimally or non-invasive choice for the patients, while providing a more representative reflection of the spatial heterogeneity in the prostate. In addition to the abovementioned blood-based tests, urine is a promising source of PCa biomarkers, offering a supplementary avenue for early detection and improved tumor classification. Four urine-based PCa tests are either FDA- or CLIA-approved: PCA3 (PROGENSA), ExoDX Prostate Intelliscore, MiPS, and SelectMDx. We will discuss these urine-based, as well as the blood-based, clinical PCa tests in more detail. We also briefly discuss a few promising biofluid marker candidates (DNA methylation, micro-RNAs) which are not in clinical application. As no single assay is perfect, we envision that a combination of biomarkers, together with imaging, will become the preferred practice.

Validation of potential RNA biomarkers for prostate cancer diagnosis and monitoring in plasma and urinary extracellular vesicles

Introduction: Prostate cancer (PCa), one of the most prevalent malignancies affecting men worldwide, presents significant challenges in terms of early detection, risk stratification, and active surveillance. In recent years, liquid biopsies have emerged as a promising non-invasive approach to complement or even replace traditional tissue biopsies. Extracellular vesicles (EVs), nanosized membranous structures released by various cells into body fluids, have gained substantial attention as a source of cancer biomarkers due to their ability to encapsulate and transport a wide range of biological molecules, including RNA. In this study, we aimed to validate 15 potential RNA biomarkers, identified in a previous EV RNA sequencing study, using droplet digital PCR. Methods: The candidate biomarkers were tested in plasma and urinary EVs collected before and after radical prostatectomy from 30 PCa patients and their diagnostic potential was evaluated in a test cohort consisting of 20 benign prostate hyperplasia (BPH) and 20 PCa patients' plasma and urinary EVs. Next, the results were validated in an independent cohort of plasma EVs from 31 PCa and 31 BPH patients. Results: We found that the levels of NKX3-1 (p = 0.0008) in plasma EVs, and tRF-Phe-GAA-3b (p < 0.0001) tRF-Lys-CTT-5c (p < 0.0327), piR-28004 (p = 0.0081) and miR-375-3p (p < 0.0001) in urinary EVs significantly decreased after radical prostatectomy suggesting that the main tissue source of these RNAs is prostate and/or PCa. Two mRNA biomarkers-GLO1 and NKX3-1 showed promising diagnostic potential in distinguishing between PCa and BPH with AUC of 0.68 and 0.82, respectively, in the test cohort and AUC of 0.73 and 0.65, respectively, in the validation cohort, when tested in plasma EVs. Combining these markers in a biomarker model yielded AUC of 0.85 and 0.71 in the test and validation cohorts, respectively. Although the PSA levels in the blood could not distinguish PCa from BPH in our cohort, adding PSA to the mRNA biomarker model increased AUC from 0.71 to 0.76. Conclusion: This study identified two novel EV-enclosed RNA biomarkers-NKX3-1 and GLO1-for the detection of PCa, and highlights the complementary nature of GLO1, NKX3-1 and PSA as combined biomarkers in liquid biopsies of PCa.

Role of exosomes in prostate cancer and male fertility

Prostate cancer (PCa) is the second most common and fifth most aggressive neoplasm among men worldwide. In the last decade, extracellular vesicle (EV) research has decoded multiple unsolved cancer-related mysteries. EVs can be classified as microvesicles, apoptotic bodies, and exosomes, among others. Exosomes play a key role in cellular signaling. Their internal cargos (nucleic acids, proteins, lipids) influence the recipient cell. In PCa, the exosome is the regulator of cancer progression. It is also a promising theranostics tool for PCa. Moreover, exosomes have strong participation in male fertility complications. This review aims to highlight the exosome theranostics signature in PCa and its association with male fertility.

Clinical Significance of Extracellular Vesicles in Prostate and Renal Cancer

Extracellular vesicles (EVs)-including apoptotic bodies, microvesicles, and exosomes-are released by almost all cell types and contain molecular footprints from their cell of origin, including lipids, proteins, metabolites, RNA, and DNA. They have been successfully isolated from blood, urine, semen, and other body fluids. In this review, we discuss the current understanding of the predictive value of EVs in prostate and renal cancer. We also describe the findings supporting the use of EVs from liquid biopsies in stratifying high-risk prostate/kidney cancer and advanced disease, such as castration-resistant (CRPC) and neuroendocrine prostate cancer (NEPC) as well as metastatic renal cell carcinoma (RCC). Assays based on EVs isolated from urine and blood have the potential to serve as highly sensitive diagnostic studies as well as predictive measures of tumor recurrence in patients with prostate and renal cancers. Overall, we discuss the biogenesis, isolation, liquid-biopsy, and therapeutic applications of EVs in CRPC, NEPC, and RCC.

Angiogenesis and prostate cancer: MicroRNAs comes into view

Angiogenesis, the formation of new blood vessels, is an important stage in the growth of cancer. Extracellular matrix, endothelial cells, and soluble substances must be carefully coordinated during the multistep procedure of angiogenesis. Inducers and inhibitors have been found to control pretty much every phase. In addition to benign prostatic hyperplasia, prostatic intraepithelial neoplasia, and angiogenesis have a critical role in the initiation and progression of prostate cancer. MicroRNA (miRNA) is endogenous, short, non-coding RNA molecules of almost 22 nucleotides play a role in regulating cellular processes and regulating several genes' expression. Through controlling endothelial migration, differentiation, death, and cell proliferation, miRNAs have a significant function in angiogenesis. A number of pathological and physiological processes, particularly prostate cancer's emergence, depend on the regulation of angiogenesis. Investigating the functions played with miRNAs in angiogenesis is crucial because it might result in the creation of novel prostate cancer therapies that entail regulating angiogenesis. The function of several miRNAs and its targeting genes engaged in cancer of the prostate angiogenesis will be reviewed in this review in light of the most recent developments. The potential clinical utility of miRNAs potentially a novel therapeutic targets will also be explored, as well as their capacity to control prostate cancer angiogenesis and the underlying mechanisms.

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.

Tumor-derived extracellular vesicle nucleic acids as promising diagnostic biomarkers for prostate cancer

Liquid biopsy as a non-invasive method has a bright future in cancer diagnosis. Tumor-related extracellular vesicles (EVs) and their components (nucleic acids, proteins, and lipids) in biofluids may exert multiple functions in tumor growth, metastasis, immune escape, and angiogenesis. Among all the components, nucleic acids have attracted the most interest due to their simplicity of extraction and detection. In this review, the biological functions of EVs in prostate cancer (PCa) genesis and progression were summarized. Moreover, the diagnostic value of EV RNA markers found in clinical body fluid samples was reviewed, including their trends, challenging isolation methods, and diagnostic efficacy. Lastly, because relatively much progress has been made in PCa, studies on EV DNA markers are also discussed.

Systematic Analysis of Tissue-Derived and Biofluid Extracellular Vesicle miRNAs Associated with Prostate Cancer

Extracellular vesicles (EVs) are emerging as biomarker candidates for early detection of prostate cancer. Studies compare EV-microRNA (miRNA) expression in individuals with prostate cancer (PCa) with cancer-free samples for diagnostic purposes. The aim of this study is to review miRNA signatures to investigate the overlap between miRNAs enriched in PCa tissue and miRNAs enriched in EVs isolated from subjects with PCa biofluids (i.e., urine, serum, and plasma). Signatures dysregulated in EVs from PCa biofluids and tissue are potentially associated with the primary tumor site and might be more indicative of PCa at an early stage. A systematic review of EV-derived miRNAs and a reanalysis of PCa tissue miRNA sequencing data for comparison is presented. Articles in the literature are screened for validated miRNA dysregulation in PCa and compared with TCGA primary PCa tumor data using DESeq2. This resulted in 190 dysregulated miRNAs being identified. Thirty-one eligible studies are identified, indicating 39 dysregulated EV-derived miRNAs. The top ten markers identified as significantly dysregulated in the PCa tissue dataset TCGA (e.g., miR-30b-3p, miR-210-3p, miR-126-3p, and miR-196a-5p) have a significant expression change in EVs with the same directionality in one or several statistically significant results. This analysis highlights several less frequently studied miRNAs in PCa literature.

Dynamic Role of Exosome microRNAs in Cancer Cell Signaling and Their Emerging Role as Noninvasive Biomarkers

Exosomes are extracellular vesicles that originate from endosomes and are released by all cells irrespective of their origin or type. They play an important role in cell communication and can act in an autocrine, endocrine, or paracrine fashion. They are 40-150 nm in diameter and have a similar composition to the cell of origin. An exosome released by a particular cell is unique since it carries information about the state of the cell in pathological conditions such as cancer. miRNAs carried by cancer-derived exosomes play a multifaceted role by taking part in cell proliferation, invasion, metastasis, epithelial-mesenchymal transition, angiogenesis, apoptosis, and immune evasion. Depending on the type of miRNA that it carries as its cargo, it can render cells chemo- or radiosensitive or resistant and can also act as a tumor suppressor. Since the composition of exosomes is affected by the cellular state, stress, and changes in the environment, they can be used as diagnostic or prognostic biomarkers. Their unique ability to cross biological barriers makes them an excellent choice as vehicles for drug delivery. Because of their easy availability and stability, they can be used to replace cancer biopsies, which are invasive and expensive. Exosomes can also be used to follow the progression of diseases and monitor treatment strategies. A better understanding of the roles and functions of exosomal miRNA can be used to develop noninvasive, innovative, and novel treatments for cancer.

Biomarkers for Prostate Cancer Bone Metastasis Detection and Prediction

Prostate cancer (PCa) causes deaths worldwide, ranking second after lung cancer. Bone metastasis (BM) frequently results from advanced PCa, affecting approximately 90% of patients, and it also often results in severe skeletal-related events. Traditional diagnostic methods for bone metastases, such as tissue biopsies and imaging, have substantial drawbacks. This article summarizes the significance of biomarkers in PCa accompanied with BM, including (1) bone formation markers like osteopontin (OPN), pro-collagen type I C-terminal pro-peptide (PICP), osteoprotegerin (OPG), pro-collagen type I N-terminal pro-peptide (PINP), alkaline phosphatase (ALP), and osteocalcin (OC); (2) bone resorption markers, including C-telopeptide of type I collagen (CTx), N-telopeptide of type I collagen (NTx), bone sialoprotein (BSP), tartrate-resistant acid phosphatase (TRACP), deoxypyridinoline (D-PYD), pyridoxine (PYD), and C-terminal pyridinoline cross-linked telopeptide of type I collagen (ICTP); (3) prostate-specific antigen (PSA); (4) neuroendocrine markers, such as chromogranin A (CgA), neuron-specific enolase (NSE), and pro-gastrin releasing peptide (ProGRP); (5) liquid biopsy markers, such as circulating tumor cells (CTCs), microRNA (miRNA), circulating tumor DNA (ctDNA), and cell-free DNA (cfDNA) and exosomes. In summary, some of these markers are already in widespread clinical use, while others still require further laboratory or clinical studies to validate their value for clinical application.

Lipid metabolism-related miRNAs with potential diagnostic roles in prostate cancer

BACKGROUND

Prostate cancer (PCa), the second most prevalent solid tumor among men worldwide, has caused greatly increasing mortality in PCa patients. The effects of lipid metabolism on tumor growth have been explored, but the mechanistic details of the association of lipid metabolism disorders with PCa remain largely elusive.

METHODS

The RNA sequencing data of the GSE45604 and The Cancer Genome Atlas-Prostate Adenocarcinoma (TCGA-PRAD) datasets were extracted from the Gene Expression Omnibus (GEO) and UCSC Xena databases, respectively. The Molecular Signatures Database (MSigDB) was utilized to identify lipid metabolism-related genes. The limma R package was used to identify differentially expressed lipid metabolism-related genes (DE-LMRGs) and differentially expressed microRNAs (DEMs). Moreover, least absolute shrinkage and selection operator (LASSO), extreme gradient boosting (XGBoost), and support vector machine-recursive feature elimination (SVM-RFE) were applied to select signature miRNAs and construct a lipid metabolism-related diagnostic model. The expression levels of selected differentially expressed lipid metabolism-related miRNAs (DE-LMRMs) in PCa and benign prostate hyperplasia (BPH) specimens were verified using quantitative real-time polymerase chain reaction (qRT‒PCR). Furthermore, a transcription factor (TF)-miRNA‒mRNA network was constructed. Eventually, Kaplan‒Meier (KM) curves were plotted to illustrate the associations between signature miRNA-related mRNAs and TFs and overall survival (OS) along with biochemical recurrence-free survival (BCR).

RESULTS

Forty-seven LMRMs were screened based on the correlation analysis of 29 DE-LMRGs and 56 DEMs, in which 27 LMRMs were stably expressed in the GSE45604 dataset. Subsequently, receiver operating characteristic (ROC) curves and machine learning methods were employed to develop a lipid metabolism-related diagnostic signature, which may be of diagnostic value for PCa patients. qRT‒PCR results showed that all seven key DE-LMRMs were differentially expressed between PCa and BPH tissues. Eventually, a TF-miRNA‒mRNA network was constructed.

CONCLUSIONS

These results suggested that 7 key diagnostic miRNAs were closely related to PCa pathological processes and provided new targets for the diagnosis and treatment of PCa. Moreover, CLIC6 and SCNN1A linked to miR-200c-3p had good prognostic potential and provided valuable insights into the pathogenesis of PCa.

Epi-miRNAs: Modern mediators of methylation status in human cancers

Methylation of the fundamental macromolecules, DNA/RNA, and proteins, is remarkably abundant, evolutionarily conserved, and functionally significant in cellular homeostasis and normal tissue/organism development. Disrupted methylation imprinting is strongly linked to loss of the physiological equilibrium and numerous human pathologies, and most importantly to carcinogenesis, tumor heterogeneity, and cancer progression. Mounting recent evidence has documented the active implication of miRNAs in the orchestration of the multicomponent cellular methylation machineries and the deregulation of methylation profile in the epigenetic, epitranscriptomic, and epiproteomic levels during cancer onset and progression. The elucidation of such regulatory networks between the miRNome and the cellular methylation machineries has led to the emergence of a novel subclass of miRNAs, namely "epi-miRNAs" or "epi-miRs." Herein, we have summarized the existing knowledge on the functional role of epi-miRs in the methylation dynamic landscape of human cancers and their clinical utility in modern cancer diagnostics and tailored therapeutics. This article is categorized under: RNA in Disease and Development > RNA in Disease.

Diagnostic value of liquid biopsy in the era of precision medicine: 10 years of clinical evidence in cancer

Liquid biopsy is a diagnostic repeatable test, which in last years has emerged as a powerful tool for profiling cancer genomes in real-time with minimal invasiveness and tailoring oncological decision-making. It analyzes different blood-circulating biomarkers and circulating tumor DNA (ctDNA) is the preferred one. Nevertheless, tissue biopsy remains the gold standard for molecular evaluation of solid tumors whereas liquid biopsy is a complementary tool in many different clinical settings, such as treatment selection, monitoring treatment response, cancer clonal evolution, prognostic evaluation, as well as the detection of early disease and minimal residual disease (MRD). A wide number of technologies have been developed with the aim of increasing their sensitivity and specificity with acceptable costs. Moreover, several preclinical and clinical studies have been conducted to better understand liquid biopsy clinical utility. Anyway, several issues are still a limitation of its use such as false positive and negative results, results interpretation, and standardization of the panel tests. Although there has been rapid development of the research in these fields and recent advances in the clinical setting, many clinical trials and studies are still needed to make liquid biopsy an instrument of clinical routine. This review provides an overview of the current and future clinical applications and opening questions of liquid biopsy in different oncological settings, with particular attention to ctDNA liquid biopsy.

Urinary extracellular vesicles miRNA-A new era of prostate cancer biomarkers

Prostate cancer is the second most common male cancer worldwide showing the highest rates of incidence in Western Europe. Although the measurement of serum prostate-specific antigen levels is the current gold standard in PCa diagnosis, PSA-based screening is not considered a reliable diagnosis and prognosis tool due to its lower sensitivity and poor predictive score which lead to a 22%-43% overdiagnosis, unnecessary biopsies, and over-treatment. These major limitations along with the heterogeneous nature of the disease have made PCa a very unappreciative subject for diagnostics, resulting in poor patient management; thus, it urges to identify and validate new reliable PCa biomarkers that can provide accurate information in regard to disease diagnosis and prognosis. Researchers have explored the analysis of microRNAs (miRNAs), messenger RNAs (mRNAs), small proteins, genomic rearrangements, and gene expression in body fluids and non-solid tissues in search of lesser invasive yet efficient PCa biomarkers. Although the presence of miRNAs in body fluids like blood, urine, and saliva initially sparked great interest among the scientific community; their potential use as liquid biopsy biomarkers in PCa is still at a very nascent stage with respect to other well-established diagnostics and prognosis tools. Up to date, numerous studies have been conducted in search of PCa miRNA-based biomarkers in whole blood or blood serum; however, only a few studies have investigated their presence in urine samples of which less than two tens involve the detection of miRNAs in extracellular vesicles isolated from urine. In addition, there exists some discrepancy around the identification of miRNAs in PCa urine samples due to the diversity of the urine fractions that can be targeted for analysis such as urine circulating cells, cell-free fractions, and exosomes. In this review, we aim to discuss research output from the most recent studies involving the analysis of urinary EVs for the identification of miRNA-based PCa-specific biomarkers.

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.

The Role of Urinary miRNAs in the Diagnosis, Management and Follow- Up of Prostatic Cancer

Diagnosis and management of prostatic cancer (PCa) cases mainly rely on levels of prostatic- specific antigen (PSA) levels. In the majority of cases, rising of PCa is usually responsible for elevated PSA. However, a wide variety of prostatic abnormalities, such as benign prostatic hyperplasia and infection or inflammation of the prostatic glands, may also impact prostate levels. Due to the low specificity and sensitivity of the PSA test, elevated PSA levels can lead to unnecessary prostate biopsies or surgical interventions, constituting this diagnostic modality a controversial screening test. Therefore, the discovery of new non-invasive biomarkers, such as urinary miRNAs, could shed light on the optimal management and follow-up of patients with prostatic lesions. This study aims to evaluate the utility of urinary miRNAs as a new PCa prognostic biomarker, discovering its current limitations and proposing methods to overwhelm current challenges.

Liquid Biopsy in Diagnosis and Prognosis of Non-Metastatic Prostate Cancer

Currently, sensitive and specific methods for the detection and prognosis of early stage PCa are lacking. To establish the diagnosis and further identify an appropriate treatment strategy, prostate specific antigen (PSA) blood test followed by tissue biopsy have to be performed. The combination of tests is justified by the lack of a highly sensitive, specific, and safe single test. Tissue biopsy is specific but invasive and may have severe side effects, and therefore is inappropriate for screening of the disease. At the same time, the PSA blood test, which is conventionally used for PCa screening, has low specificity and may be elevated in the case of noncancerous prostate tumors and inflammatory conditions, including benign prostatic hyperplasia and prostatitis. Thus, diverse techniques of liquid biopsy have been investigated to supplement or replace the existing tests of prostate cancer early diagnosis and prognostics. Here, we provide a review on the advances in diagnosis and prognostics of non-metastatic prostate cancer by means of various biomarkers extracted via liquid biopsy, including circulating tumor cells, exosomal miRNAs, and circulating DNAs.

An overview of prostate cancer (PCa) diagnosis: Potential role of miRNAs

Prostate cancer is the second most frequently diagnosed cancer among men worldwide, with the estimated sixth leading cause of cancer death. Despite major advancements in clinical biology and imaging, digital rectal examination (DRE), prostate-specific antigen (PSA), and biopsies indication remain the keystone for screening. Several kits are used to detect genomic changes and non-coding RNAs in the sample. However, its indication remains controversial for screening purposes. There is an urged need for non-invasive biomarkers to implement precision medicine. Recent research shows that miRNAs have an important role in the diagnostic, prognostic, and therapeutic agents as non-invasive biomarkers. Though prostate cancer data remains controversial in other cancer types, such as breast cancer, miR-21 expression is upregulated. Here, we reported a prolonged revision of miRNAs as prostate cancer prognostic, diagnostic, and predictive tools, including data on androgen receptor (AR) signaling, epithelial-mesenchymal transition (EMT) process, and cancer stem cells (CSCs) regulation. The combined utilization of miRNAs with other tests will help patients and clinicians to select the most appropriate personalized treatment and to avoid overdiagnosis and unnecessary biopsies. Future clinical applications of our reported novel miRNAs have a substantial role in the primary diagnosis of prostate cancer to help treatment decisions.

The Potential of MicroRNAs as Non-Invasive Prostate Cancer Biomarkers: A Systematic Literature Review Based on a Machine Learning Approach

Simple Summary

Prostate cancer (PCa) is the most common cancer in men worldwide. Screening and diagnosis are based on prostate-specific antigen (PSA) blood testing and digital rectal examination. Nevertheless, these methods are not specific and have a high risk of mistaken results. This has led to overtreatment and unnecessary radical therapy; thus, better prognostic tools are urgently needed. In this view, microRNAs (miRs) appear as potential non-invasive biomarkers for PCa diagnosis, prognosis, and therapy. As the scientific literature available in this field is huge and very often controversial, we identified and discussed three topics that characterize the investigated research area by combining the big data from the literature together with a novel machine learning approach. By analyzing the papers clustered into these topics we have offered a deeper understanding of the current research, which helps to contribute to the advancement of this research field.

Abstract

Background: Prostate cancer (PCa) is the second leading cause of cancer-related deaths in men. Although the prostate-specific antigen (PSA) test is used in clinical practice for screening and/or early detection of PCa, it is not specific, thus resulting in high false-positive rates. MicroRNAs (miRs) provide an opportunity as biomarkers for diagnosis, prognosis, and recurrence of PCa. Because the size of the literature on it is increasing and often controversial, this study aims to consolidate the state-of-art of relevant published research. Methods: A Systematic Literature Review (SLR) approach was applied to analyze a set of 213 scientific publications through a text mining method that makes use of the Latent Dirichlet Allocation (LDA) algorithm. Results and Conclusions: The result of this activity, performed through the MySLR digital platform, allowed us to identify a set of three relevant topics characterizing the investigated research area. We analyzed and discussed all the papers clustered into them. We highlighted that several miRs are associated with PCa progression, and that their detection in patients’ urine seems to be the more reliable and promising non-invasive tool for PCa diagnosis. Finally, we proposed some future research directions to help future scientists advance the field further.

Small extracellular vesicles as a multicomponent biomarker platform in urinary tract carcinomas

Extracellular vesicles are a large group of nano-sized vesicles released by all cells. The variety of possible cargo (mRNAs, miRNAs, lncRNAs, proteins, and lipids) and the presence of surface proteins, signaling molecules, and receptor ligands make them a rich source of biomarkers for malignancy diagnosis. One of the groups gathering the most interest in cancer diagnostic applications is small extracellular vesicles (sEVs), with ≤200 nm diameter, mainly composed of exosomes. Many studies were conducted recently, evaluating the diagnostic potential of sEVs in urinary tract carcinomas (UTCs), discovering and clinically evaluating various classes of biomarkers. The amount of research concerning different types of UTCs understandably reflects their incidence. sEV cargos getting the most interest are non-coding RNAs (miRNA and lncRNA). However, implementation of other approaches such as metabolomic and proteomic analysis is also evaluated. The results of many studies indicate that sEVs have an essential role in the cancer process and possess many possible diagnostic and prognostic applications for UTC. The relative ease of obtaining biofluids rich in sEVs (urine and blood) confirms that sEVs are essential for UTC detection in the liquid biopsy approach. A noticeable rise in research quality is observed as more researchers are aware of the research standardization necessity, which is essential for considering the clinical application of their findings.

Overcoming Obstacles in Liquid Biopsy Developments for Prostate Cancer

Prostate cancer is one of the most common malignancies in men. Over time, it can metastasize and become lethal once it exhausts hormonal therapies and transitions into castration-resistant prostate cancer (CRPC). Several therapies have been recently approved for advanced prostate cancer, but identifying biomarkers for current treatments and searching for more effective treatments are urgently needed. Liquid biopsy is a powerful tool for isolating genetic material, proteins, and whole tumor cells from the blood. In recent decades, this technology has rapidly advanced, allowing for better insights into the pathogenesis and treatment response in different stages of prostate cancer. In this review, we summarize important clinical studies involving liquid biopsies in prostate cancer with a focus on advanced disease, notably regarding circulating tumor DNA, circulating tumor cells, and exosomes. We highlight the progress and the challenges that still exist for these technologies. Finally, we discuss promising avenues that will further expand the importance of liquid biopsy in the care for prostate cancer patients.

Urinary microRNAs and Their Significance in Prostate Cancer Diagnosis: A 5-Year Update

Simple Summary

Current diagnostics of prostate cancer often show unsatisfactory results, leading to delayed detection or overtreatment. Urinary microRNAs are a class of promising non-invasive biomarkers. Although many studies have been conducted on this topic in the last five years, there is little agreement on the data obtained. This review aims to discuss new knowledge but also focuses on technical aspects affecting urinary miRNA analysis.

Abstract

Current routine screening methods for the diagnosis of prostate cancer (PCa) have significantly increased early detection of the disease but often show unsatisfactory analytical parameters. A class of promising markers represents urinary microRNAs (miRNAs). In the last five years, there has been an extensive increase in the number of studies on this topic. Thus, this review aims to update knowledge and point out technical aspects affecting urinary miRNA analysis. The review of relevant literature was carried out by searching the PubMed database for the keywords: microRNA, miRNA, urine, urinary, prostate cancer, and diagnosis. Papers discussed in this review were retrieved using PubMed, and the search strategy was as follows: (urine OR urinary) WITH (microRNA OR miRNA) AND prostate cancer. The search was limited to the last 5 years, January 2017 to December 2021. Based on the defined search strategy, 31 original publications corresponding to the research topic were identified, read and reviewed to present the latest findings and to assess possible translation of urinary miRNAs into clinical practice. Reviews or older publications were read and cited if they valuably extended the context and contributed to a better understanding. Urinary miRNAs are potentially valuable markers for the diagnosis of prostate cancer. Despite promising results, there is still a need for independent validation of exploratory data, which follows a strict widely accepted methodology taking into account the shortcomings and factors influencing the analysis.

Isolation and Characterization of Urinary Extracellular Vesicles from Healthy Donors and Patients with Castration-Resistant Prostate Cancer

Prostate cancer (PCa) is the most commonly diagnosed malignancy among men in developed countries. The five-year survival rate for men diagnosed with early-stage PCa is approximately 100%, while it is less than 30% for castration-resistant PCa (CRPC). Currently, the detection of prostate-specific antigens as biomarkers for the prognosis of CRPC is criticized because of its low accuracy, high invasiveness, and high false-positive rate. Therefore, it is important to identify new biomarkers for prediction of CRPC progression. Extracellular vesicles (EVs) derived from tumors have been highlighted as potential markers for cancer diagnosis and prognosis. Specifically, urinary EVs directly reflect changes in the pathophysiological conditions of the urogenital system because it is exposed to prostatic secretions. Thus, detecting biomarkers in urinary EVs provides a promising approach for performing an accurate and non-invasive liquid biopsy for CPRC. In this study, we effectively isolated urinary EVs with low protein impurities using size-exclusion chromatography combined with ultrafiltration. After EV isolation and characterization, we evaluated the miRNAs in urinary EVs from healthy donors and patients with CRPC. The results indicated that miRNAs (miR-21-5p, miR-574-3p, and miR-6880-5p) could be used as potential biomarkers for the prognosis of CRPC. This analysis of urinary EVs contributes to the fast and convenient prognosis of diseases, including CRPC, in the clinical setting.

Urinary exosomes: Emerging therapy delivery tools and biomarkers for urinary system diseases

Urinary exosomes (UE) are small circular membranous vesicles with a lipid bilayer with a diameter of 40-160 nm secreted by epithelial cells of the kidney and genitourinary system, which can reflect the physiological and functional status of secretory cells. Protein and RNA in exosomes can be used as markers for diseases diagnosis. Urine specimens are available and non-invasive. The protein and RNA in UE are more stable than the soluble protein and RNA in urine, which have broad application prospects in the diagnosis of urinary system diseases. This article reviews the recent advances in the application of protein or RNA in UE as markers to the diagnosis of urinary system diseases.

Urine Cell-Free MicroRNAs in Localized Prostate Cancer Patients

Prostate cancer (PCa) is the most common cancer in men. Prostate-specific antigen screening is recommended for the detection of PCa. However, its specificity is limited. Thus, there is a need to find more reliable biomarkers that allow non-invasive screening for early-stage PCa. This study aims to explore urine microRNAs (miRs) as diagnostic biomarkers for PCa. We assessed cell-free miR (cfmiR) profiles of urine and plasma samples from pre- and post-operative PCa patients (n = 11) and normal healthy donors (16 urine and 24 plasma) using HTG EdgeSeq miRNA Whole Transcriptome Assay based on next-generation sequencing. Furthermore, tumor-related miRs were detected in formalin-fixed paraffin-embedded tumor tissues obtained from patients with localized PCa. Specific cfmiRs signatures were found in urine samples of localized PCa patients using differential expression analysis. Forty-two cfmiRs that were detected were common to urine, plasma, and tumor samples. These urine cfmiRs may have potential utility in diagnosing early-stage PCa and complementing or improving currently available PCa screening assays. Future studies may validate the findings.

Isoflurane Promotes Cell Proliferation, Invasion, and Migration by Regulating BACH1 and miR-375 in Prostate Cancer Cells In Vitro

The aim of this study was to investigate the mechanism of isoflurane in proliferation, invasion, and migration in prostate cancer (PC) cells in vitro by regulating BACH1 and miR-375. The effect of different concentrations of isoflurane (0%, 0.5%, 1%, and 2%) on PC cell proliferation (PC3 and 22RV1) was measured. After PC cells and normal human prostate stromal immortalized WPMY-1 cells were treated with isoflurane, BACH1 and miR-375 expression was measured. Subsequently, PC3 and 22RV1 cells underwent gain- and loss-of-function assays with or without 4-h 2% isoflurane pretreatment. The levels of miR-375, BACH1, and PTEN were assessed. The binding of BACH1 to miR-375 promoter was detected by ChIP assay. Dual-luciferase reporter assay detected the targeting relationship of miR-375 with BACH1 and PTEN. Isoflurane promoted PC3 and 22RV1 cell proliferation. In addition, isoflurane elevated the levels of BACH1 and miR-375 in a dosage-dependent manner in PC cells. Transfection with miR-375 inhibitor or sh-BACH1 repressed PC cell proliferation, invasion, and migration, while exposure to 2% isoflurane for 4 h before transfection counteracted the inhibitory effects of sh-BACH1 or miR-375 inhibitor on PC cells. PTEN expression was suppressed after 2% isoflurane treatment, but the transfection with miR-375 inhibitor partly abrogated this suppressive effect in PC cells. Moreover, BACH1 bound to miR-375 and miR-375 negatively targeted PTEN. miR-375 mimic could partially reverse the inhibitory effects of sh-BACH1 on the proliferation, invasion, and migration of isoflurane-treated PC cells. Isoflurane facilitated PC cell proliferation, migration, and invasion by activating BACH1 to upregulate miR-375.

MicroRNAs as Potential Liquid Biopsy Biomarker for Patients with Castration-Resistant Prostate Cancer

Purpose

Patients and Methods

Results

Conclusion

Urinary microRNAs can predict response to abiraterone acetate in castration resistant prostate cancer: A pilot study

BACKGROUND

Despite novel agents have been introduced to treat castration resistant prostate cancer (CRPC) during the last decade, up to one-third of CRPC patients face primary resistance to new generation compounds. Therefore, sensitive molecular tools are urgently needed for reliable treatment selection and response prediction. This study aimed to evaluate urinary miRNAs and blood circulating androgen receptor (AR) transcript level as a tool for noninvasive outcome prediction for CRPC patients undergoing abiraterone acetate (AA) therapy.

METHODS

Prostate cancer-specific miR-148a, -365, -375, and -429 were analyzed in 129 urine samples collected from 100 CRPC patients before and during AA therapy via quantitative reverse transcription PCR. To test the prognostic value, urinary miRNA levels alone, as well as combined with AR level were associated with progression-free survival (PFS) and overall survival (OS).

RESULTS

Level of urinary miR-375 was the highest in CRPC in comparison to noncancerous controls, as well as in combination with miR-429 was predictive for short PFS in AA-treated patients (HR = 2.2, 95% CI: 1.1-4.2, p = 0.023). Especially high prognostic power of all analyzed miRNAs was observed in CRPC cases with high blood AR levels. For PFS prediction a tandem of miR-429 and high AR reached HR of 5.0 (95% CI: 2.2-11.8, p < 0.001), while for prediction of OS the best combination was demonstrated by miR-148a and AR with HR of 3.1 (95% CI: 1.4-7.1, p = 0.006).

CONCLUSIONS

Urinary miRNAs could be used as prognostic biomarkers for CRPC patients to predict response to AA therapy, especially for the cases with high blood AR levels.

Liquid Biopsy for Promising Non-invasive Diagnostic Biomarkers in Parasitic Infections

BACKGROUND

Liquid biopsy refers to the sampling and molecular analysis of body fluids such as blood, saliva, and urine in contrast to conventional tissue biopsies. Liquid biopsy approach can offer powerful non-invasive biomarkers (circulating markers) for diagnosis and monitoring treatment response of a variety of diseases, including parasitic infections.

METHODS

In this review, we concentrate on cell-free DNA (cfDNA), microRNA (miRNA), and exosomes in the published literature.

RESULTS

Considering the high prevalence and severity of parasitic infections worldwide, circulating biomarkers can provide a new insight into the diagnosis and prognosis of parasites in the near future. Moreover, identifying and characterizing parasite- or host-derived circulating markers are important for a better understanding of the pathogenesis of parasite infection and host-parasite relationship at the molecular level. Profiling of biomarkers for parasitic diseases is a promising potential field, though further studies and optimization strategies are required, both in vitro and in vivo.

CONCLUSION

In this review, we discuss three approaches in the liquid biopsy including circulating cfDNA, miRNAs, and exosomes for diagnosis and evaluation of parasites and summarize circulating biomarkers in non-invasive samples during parasitic infections.

Potential of miRNAs in urinary extracellular vesicles for management of active surveillance in prostate cancer patients

BACKGROUND

Active surveillance is an alternative to radical treatment for patients with low-risk prostate cancer, which could also benefit some patients with intermediate risk. We have investigated the use of miRNA in urinary extracellular vesicles to stratify these patients.

METHODS

NGS was performed to profile the miRNAs from small urinary extracellular vesicles in a cohort of 70 patients with prostate cancer ISUP Grade 1, 2 or 3. The most promising candidates were then analysed by RT-qPCR in a new cohort of 60 patients.

RESULTS

NGS analysis identified nine miRNAs differentially expressed in at least one of the comparisons. The largest differences were found with miR-1290 (Grade 3 vs. 1), miR-320a-3p (Grade 3 vs. 2) and miR-155-5p (Grade 2 vs. 1). Combinations of 2-3 miRNAs were able to differentiate between two ISUP grades with an AUC 0.79-0.88. RT-qPCR analysis showed a similar trend for miR-186-5p and miR-30e-5p to separate Grade 3 from 2, and miR-320a-3p to separate Grade 2 from 1.

CONCLUSIONS

Using NGS, we have identified several miRNAs that discriminate between prostate cancer patients with ISUP Grades 1, 2 and 3. Moreover, miR-186-5p, miR-320a-3p and miR-30e-5p showed a similar behaviour in an independent cohort using an alternative analytical method. Our results show that miRNAs from urinary vesicles can be potentially useful as liquid biopsies for active surveillance.

Extracellular vesicles as a source of prostate cancer biomarkers in liquid biopsies: a decade of research

Prostate cancer is a global cancer burden and considerable effort has been made through the years to identify biomarkers for the disease. Approximately a decade ago, the potential of analysing extracellular vesicles in liquid biopsies started to be envisaged. This was the beginning of a new exciting area of research investigating the rich molecular treasure found in extracellular vesicles to identify biomarkers for a variety of diseases. Vesicles released from prostate cancer cells and cells of the tumour microenvironment carry molecular information about the disease that can be analysed in several biological fluids. Numerous studies document the interest of researchers in this field of research. However, methodological issues such as the isolation of vesicles have been challenging. Remarkably, novel technologies, including those based on nanotechnology, show promise for the further development and clinical use of extracellular vesicles as liquid biomarkers. Development of biomarkers is a long and complicated process, and there are still not many biomarkers based on extracellular vesicles in clinical use. However, the knowledge acquired during the last decade constitutes a solid basis for the future development of liquid biopsy tests for prostate cancer. These are urgently needed to bring prostate cancer treatment to the next level in precision medicine.

Chimeric nanocomposites for the rapid and simple isolation of urinary extracellular vesicles

Cancer cell-derived extracellular vesicles (EVs) are promising biomarkers for cancer diagnosis and prognosis. However, the lack of rapid and sensitive isolation techniques to obtain EVs from clinical samples at a sufficiently high yield limits their practicability. Chimeric nanocomposites of lactoferrin conjugated 2,2-bis(methylol)propionic acid dendrimer-modified magnetic nanoparticles (LF-bis-MPA-MNPs) are fabricated and used for simple and sensitive EV isolation from various biological samples via a combination of electrostatic interaction, physically absorption, and biorecognition between the surfaces of the EVs and the LF-bis-MPA-MNPs. The speed, efficiency, recovery rate, and purity of EV isolation by the LF-bis-MPA-MNPs are superior to those obtained by using established methods. The relative expressions of exosomal microRNAs (miRNAs) from isolated EVs in cancerous cell-derived exosomes are verified as significantly higher than those from noncancerous ones. Finally, the chimeric nanocomposites are used to assess urinary exosomal miRNAs from urine specimens from 20 prostate cancer (PCa), 10 benign prostatic hyperplasia (BPH), patients and 10 healthy controls. Significant up-regulation of miR-21 and miR-346 and down-regulation of miR-23a and miR-122-5p occurs in both groups compared to healthy controls. LF-bis-MPA-MNPs provide a rapid, simple, and high yield method for human excreta analysis in clinical applications.

Nanomaterials-Based Urinary Extracellular Vesicles Isolation and Detection for Non-invasive Auxiliary Diagnosis of Prostate Cancer

Extracellular vesicles (EVs) are natural nanoparticles secreted by cells in the body and released into the extracellular environment. They are associated with various physiological or pathological processes, and considered as carriers in intercellular information transmission, so that EVs can be used as an important marker of liquid biopsy for disease diagnosis and prognosis. EVs are widely present in various body fluids, among which, urine is easy to obtain in large amount through non-invasive methods and has a small dynamic range of proteins, so it is a good object for studying EVs. However, most of the current isolation and detection of EVs still use traditional methods, which are of low purity, time consuming, and poor efficiency; therefore, more efficient and highly selective techniques are urgently needed. Recently, inspired by the nanoscale of EVs, platforms based on nanomaterials have been innovatively explored for isolation and detection of EVs from body fluids. These newly developed nanotechnologies, with higher selectivity and sensitivity, greatly improve the precision of isolation target EVs from urine. This review focuses on the nanomaterials used in isolation and detection of urinary EVs, discusses the advantages and disadvantages between traditional methods and nanomaterials-based platforms, and presents urinary EV-derived biomarkers for prostate cancer (PCa) diagnosis. We aim to provide a reference for researchers who want to carry out studies about nanomaterial-based platforms to identify urinary EVs, and we hope to summarize the biomarkers in downstream analysis of urinary EVs for auxiliary diagnosis of PCa disease in detail.

Exosomal miRNAs from Prostate Cancer Impair Osteoblast Function in Mice

Prostate cancer (PCa) is the most frequent malignancy in older men with a high propensity for bone metastases. Characteristically, PCa causes osteosclerotic lesions as a result of disrupted bone remodeling. Extracellular vesicles (EVs) participate in PCa progression by conditioning the pre-metastatic niche. However, how EVs mediate the cross-talk between PCa cells and osteoprogenitors in the bone microenvironment remains poorly understood. We found that EVs derived from murine PCa cell line RM1-BM increased metabolic activity, vitality, and cell proliferation of osteoblast precursors by >60%, while significantly impairing mineral deposition (-37%). The latter was further confirmed in two complementary in vivo models of ossification. Accordingly, gene and protein set enrichments of osteoprogenitors exposed to EVs displayed significant downregulation of osteogenic markers and upregulation of proinflammatory factors. Additionally, transcriptomic profiling of PCa-EVs revealed the abundance of three microRNAs, miR-26a-5p, miR-27a-3p, and miR-30e-5p involved in the suppression of BMP-2-induced osteogenesis in vivo, suggesting the critical role of these EV-derived miRNAs in PCa-mediated suppression of osteoblast activity. Taken together, our results indicate the importance of EV cargo in cancer-bone cross-talk in vitro and in vivo and suggest that exosomal miRNAs may contribute to the onset of osteosclerotic bone lesions in PCa.

Recent Advances in Device Engineering and Computational Analysis for Characterization of Cell-Released Cancer Biomarkers

During cancer progression, tumors shed different biomarkers into the bloodstream, including circulating tumor cells (CTCs), extracellular vesicles (EVs), circulating cell-free DNA (cfDNA), and circulating tumor DNA (ctDNA). The analysis of these biomarkers in the blood, known as 'liquid biopsy' (LB), is a promising approach for early cancer detection and treatment monitoring, and more recently, as a means for cancer therapy. Previous reviews have discussed the role of CTCs and ctDNA in cancer progression; however, ctDNA and EVs are rapidly evolving with technological advancements and computational analysis and are the subject of enormous recent studies in cancer biomarkers. In this review, first, we introduce these cell-released cancer biomarkers and briefly discuss their clinical significance in cancer diagnosis and treatment monitoring. Second, we present conventional and novel approaches for the isolation, profiling, and characterization of these markers. We then investigate the mathematical and in silico models that are developed to investigate the function of ctDNA and EVs in cancer progression. We convey our views on what is needed to pave the way to translate the emerging technologies and models into the clinic and make the case that optimized next-generation techniques and models are needed to precisely evaluate the clinical relevance of these LB markers.

Prognostic value of miR-21 for prostate cancer: a systematic review and meta-analysis

Elevated levels of miR-21 expression are associated with many cancers, suggesting it may be a promising clinical biomarker. In prostate cancer (PCa), however, there is still no consensus about the usefulness of miR-21 as an indicator of disease progression. This systematic review and meta-analysis was conducted to investigate the value of miR-21 expression as a prognostic measurement in PCa patients. Medline (Ovid), EMBASE, Web of Science, Scopus and Cochrane Library databases were systematically searched for relevant publications between 2010 to 2021. Studies exploring the relationship between miR-21 expression, PCa prognosis and clinicopathological factors were selected for review. Those reporting hazard ratio (HR) and 95% confidence intervals (CIs) were subject to meta-analyses. Fixed-effect models were employed to calculated pooled HRs and 95% CIs. Risk of bias in each study was assessed using QUIPS tool. Certainty of evidence in each meta-analysis was assessed using GRADE guidelines. A total of 64 studies were included in the systematic review. Of these, 11 were eligible for inclusion in meta-analysis. Meta-analyses revealed that high miR-21 expression was associated with poor prognosis: HR = 1.58 (95% CI = 1.19–2.09) for biochemical recurrence, MODERATE certainty; HR = 1.46 (95% CI = 1.06–2.01) for death, VERY LOW certainty; and HR = 1.26 (95% CI = 0.70–2.27) for disease progression, VERY LOW certainty. Qualitative summary revealed elevated miR-21 expression was significantly positively associated with PCa stage, Gleason score and risk groups. This systematic review and meta-analysis suggests that elevated levels of miR-21 are associated with poor prognosis in PCa patients. miR-21 expression may therefore be a useful prognostic biomarker in this disease.

Regulation of Neuroendocrine-like Differentiation in Prostate Cancer by Non-Coding RNAs

Neuroendocrine prostate cancer (NEPC) represents a variant of prostate cancer that occurs in response to treatment resistance or, to a much lesser extent, de novo. Unravelling the molecular mechanisms behind transdifferentiation of cancer cells to neuroendocrine-like cancer cells is essential for development of new treatment opportunities. This review focuses on summarizing the role of small molecules, predominantly microRNAs, in this phenomenon. A published literature search was performed to identify microRNAs, which are reported and experimentally validated to modulate neuroendocrine markers and/or regulators and to affect the complex neuroendocrine phenotype. Next, available patients’ expression datasets were surveyed to identify deregulated microRNAs, and their effect on NEPC and prostate cancer progression is summarized. Finally, possibilities of miRNA detection and quantification in body fluids of prostate cancer patients and their possible use as liquid biopsy in prostate cancer monitoring are discussed. All the addressed clinical and experimental contexts point to an association of NEPC with upregulation of miR-375 and downregulation of miR-34a and miR-19b-3p. Together, this review provides an overview of different roles of non-coding RNAs in the emergence of neuroendocrine prostate cancer.

Liquid biopsy in prostate cancer: current status and future challenges of clinical application

PURPOSE

Liquid biopsy refers to the detection and analysis of the components from biological fluids non-invasively, including circulating tumor cells, nucleic acids, and extracellular vesicles (EVs). It is necessary to review the clinical value of liquid biopsy assays in PC and explore its potential application.

MATERIALS AND METHODS

We systematically reviewed of PubMed was performed to identify relevant literature on potential clinical applications of circulating tumor cells, circulating nucleic acids, and EVs in prostate cancer (PC).

RESULTS

Liquid biopsy has emerged as a powerful tool to elucidate dynamic genomic, transcriptomic, and epigenomic tumor profiling in real-time. Here, the potential clinical applications of liquid biopsy include early detection, prognosis of survival, assessment of treatment response, and mechanisms of drug resistance in PC.

CONCLUSIONS

Liquid biopsy provides great value in diagnosis, prognosis, and treatment response in PC. Characterization of liquid biopsy components provides benefits both to unravel underlying resistance mechanisms and to exploit novel clinically actionable targets in PC. In addition, we suggest that analysis of multiparametric liquid biopsies should be analyzed comprehensively, assisting in monitoring tumor characteristics in real-time, guiding therapeutic selection, and early therapeutic switching during disease progression.

Semen as a rich source of diagnostic biomarkers for prostate cancer: latest evidence and implications

Prostate cancer (PCa) is one of the most common cancers in men and the cause of numerous cancer deaths in the world. Nowadays, based on diagnostic criteria, prostate-specific antigen (PSA) evaluation and rectal examination are used to diagnose prostate-related malignancies. However, due to the different types of PCa, there are several doubts about the diagnostic value of PSA. On the other hand, semen is considered an appropriate source and contains various biomarkers in non-invasive diagnosing several autoimmune disorders and malignancies. Evidence suggests that analysis of semen biomarkers could be helpful in PCa diagnosis. Therefore, due to the invasiveness of most diagnostic methods in PCa, the use of semen as a biologic sample containing various biomarkers can lead to the emergence of novel and non-invasive diagnostic approaches. This review summarized recent studies on the use of various seminal biomarkers for diagnosis, prognosis and prediction of PCa.

Cellular senescence as a possible link between prostate diseases of the ageing male

Senescent cells accumulate with age in all tissues. Although senescent cells undergo cell-cycle arrest, these cells remain metabolically active and their secretome - known as the senescence-associated secretory phenotype - is responsible for a systemic pro-inflammatory state, which contributes to an inflammatory microenvironment. Senescent cells can be found in the ageing prostate and the senescence-associated secretory phenotype and can be linked to BPH and prostate cancer. Indeed, a number of signalling pathways provide biological plausibility for the role of senescence in both BPH and prostate cancer, although proving causality is difficult. The theory of senescence as a mechanism for prostate disease has a number of clinical implications and could offer opportunities for targeting in the future.

Emerging Role of Extracellular Vesicles in Prostate Cancer

Prostate cancer (PCa) is the second most common cancer among men in the United States. While the use of prostate-specific antigen has improved the ability to screen and ultimately diagnose PCa, there still remain false positives due to noncancerous conditions in the prostate gland itself and other prognostic biomarkers for PCa are needed. Contents within extracellular vesicles (EVs) have emerged as promising biomarkers that can give valuable information about disease state, and have the additional benefit of being acquired through noninvasive liquid biopsies. Meaningful communication between cancer cells and the microenvironment are carried by EVs, which impact important cellular processes in prostate cancer such as metastasis, immune regulation, and drug resistance.

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.

Implications and pitfalls for cancer diagnostics exploiting extracellular vesicles

Early detection of cancer in order to facilitate timely therapeutic interventions is an unsolved problem in today's clinical diagnostics. Tumors are detected so far mostly after pathological symptoms have emerged (usually already in progressed disease states), within preventive screenings, or occasionally as incidental finding. The emergence of extracellular vesicle (EV) analytics in combination with liquid biopsy sampling opened a plethora of new possibilities for the detection of tumors (and other diseases). This review gives an overview of the diversity of currently known EV species and the relevant cargo molecules representing potential biomarkers to detect, identify and characterize tumor cells. A number of molecules reported in recent years to be valuable targets for different aspects of cancer diagnostics, are presented. Furthermore, we discuss (technical) challenges and pitfalls related to the various potential applications (screening, diagnosis, prognosis, monitoring) of liquid biopsy based EV analytics, and give an outlook to possible future directions of this emerging field in oncology.