Exosomes as biomarker treasure chests for prostate cancer.
TL;DR: This narrative review describes recent progress in exosome research, focusing on the potential role of exosomes as novel biomarkers for prostate cancer (PCa), to acquaint clinicians and researchers in the field of urology with the potential roles of exOSomes as biomarker treasure chests and with their clinical value.
About: This article is published in European Urology.The article was published on 2011-05-01. It has received 269 citations till now. The article focuses on the topics: Exosome & Microvesicle.
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TL;DR: It is shown here that most exosomes derived from standard preparations do not harbor many copies of miRNA molecules, and are, therefore, individually unlikely to be functional as vehicles for miRNA-based communication.
Abstract: Exosomes have been proposed as vehicles for microRNA (miRNA) -based intercellular communication and a source of miRNA biomarkers in bodily fluids. Although exosome preparations contain miRNAs, a quantitative analysis of their abundance and stoichiometry is lacking. In the course of studying cancer-associated extracellular miRNAs in patient blood samples, we found that exosome fractions contained a small minority of the miRNA content of plasma. This low yield prompted us to perform a more quantitative assessment of the relationship between miRNAs and exosomes using a stoichiometric approach. We quantified both the number of exosomes and the number of miRNA molecules in replicate samples that were isolated from five diverse sources (i.e., plasma, seminal fluid, dendritic cells, mast cells, and ovarian cancer cells). Regardless of the source, on average, there was far less than one molecule of a given miRNA per exosome, even for the most abundant miRNAs in exosome preparations (mean ± SD across six exosome sources: 0.00825 ± 0.02 miRNA molecules/exosome). Thus, if miRNAs were distributed homogenously across the exosome population, on average, over 100 exosomes would need to be examined to observe one copy of a given abundant miRNA. This stoichiometry of miRNAs and exosomes suggests that most individual exosomes in standard preparations do not carry biologically significant numbers of miRNAs and are, therefore, individually unlikely to be functional as vehicles for miRNA-based communication. We propose revised models to reconcile the exosome-mediated, miRNA-based intercellular communication hypothesis with the observed stoichiometry of miRNAs associated with exosomes.
852 citations
Cites background from "Exosomes as biomarker treasure ches..."
...Multiple independent studies have reported that exosomes contain miRNA, and exosomes have been proposed to be treasure chests for biomarker applications (22, 26)....
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TL;DR: Extracellular vesicles are emerging as potent genetic information transfer agents underpinning a range of biological processes and with therapeutic potential.
Abstract: Exosomes and microvesicles are extracellular nanovesicles released by most but not all cells. They are specifically equipped to mediate intercellular communication via the transfer of genetic information, including the transfer of both coding and non-coding RNAs, to recipient cells. As a result, both exosomes and microvesicles play a fundamental biological role in the regulation of normal physiological as well as aberrant pathological processes, via altered gene regulatory networks and/or via epigenetic programming. For example, microvesicle-mediated genetic transfer can regulate the maintenance of stem cell plasticity and induce beneficial cell phenotype modulation. Alternatively, such vesicles play a role in tumor pathogenesis and the spread of neurodegenerative diseases via the transfer of specific microRNAs and pathogenic proteins. Given this natural property for genetic information transfer, the possibility of exploiting these vesicles for therapeutic purposes is now being investigated. Stem cell-derived microvesicles appear to be naturally equipped to mediate tissue regeneration under certain conditions, while recent evidence suggests that exosomes might be harnessed for the targeted delivery of human genetic therapies via the introduction of exogenous genetic cargoes such as siRNA. Thus, extracellular vesicles are emerging as potent genetic information transfer agents underpinning a range of biological processes and with therapeutic potential.
792 citations
TL;DR: The detailed lipid composition provided in this study may be useful to understand the mechanism of exosome formation, release and function, and several of the lipids enriched in exosomes could potentially be used as cancer biomarkers.
560 citations
TL;DR: A straightforward method to estimate the purity of vesicle preparations by comparing the ratio of nano-vesicle counts to protein concentration, using tools such as the increasingly available NanoSight platform and a colorimetric protein assaysuch as the BCA-assay is proposed.
Abstract: We propose a straightforward method to estimate the purity of vesicle preparations by comparing the ratio of nano-vesicle counts to protein concentration, using tools such as the increasingly available NanoSight platform and a colorimetric protein assay such as the BCA-assay. Such an approach is simple enough to apply to every vesicle preparation within a given laboratory, assisting researchers as a routine quality control step. Also, the approach may aid in comparing/standardising vesicle purity across diverse studies, and may be of particular importance in evaluating vesicular biomarkers. We herein propose some criteria to aid in the definition of pure vesicles.
542 citations
Cites background from "Exosomes as biomarker treasure ches..."
...The utility of extracellular vesicles as disease biomarkers has attracted considerable interest in recent years (1)....
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TL;DR: The current state of prostate cancer biomarker research, including the PSA revolution, its impact on early cancer detection, the recent advances in biomarker discovery, and the future efforts that promise to improve clinical management of this disease are reviewed.
Abstract: Since the introduction of serum prostate-specific antigen (PSA) screening 25 years ago, prostate cancer diagnosis and management have been guided by this biomarker. Yet, PSA has proven controversial as a screening assay owing to several inherent limitations. The next wave of prostate cancer biomarkers has emerged, introducing new assays in serum and urine that may supplement or, in time, replace PSA because of their higher cancer specificity. This expanding universe of biomarkers has been facilitated, in large part, by new genomic technologies that have enabled an unbiased look at cancer biology. Such efforts have produced several notable success stories that involve rapidly moving biomarkers from the bench to the clinic. However, biomarker research has centered on disease diagnostics, rather than prognosis and prediction, which would address disease management. The development of biomarkers to stratify risk of prostate cancer aggressiveness at the time of screening remains the greatest unmet clinical need in prostate cancer. We review the current state of prostate cancer biomarker research, including the PSA revolution, its impact on early cancer detection, the recent advances in biomarker discovery, and the future efforts that promise to improve clinical management of this disease.
425 citations
References
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TL;DR: It is shown that exosomes contain both mRNA and microRNA, which can be delivered to another cell, and can be functional in this new location, and it is proposed that this RNA is called “exosomal shuttle RNA” (esRNA).
Abstract: Exosomes are vesicles of endocytic origin released by many cells. These vesicles can mediate communication between cells, facilitating processes such as antigen presentation. Here, we show that exosomes from a mouse and a human mast cell line (MC/9 and HMC-1, respectively), as well as primary bone marrow-derived mouse mast cells, contain RNA. Microarray assessments revealed the presence of mRNA from approximately 1300 genes, many of which are not present in the cytoplasm of the donor cell. In vitro translation proved that the exosome mRNAs were functional. Quality control RNA analysis of total RNA derived from exosomes also revealed presence of small RNAs, including microRNAs. The RNA from mast cell exosomes is transferable to other mouse and human mast cells. After transfer of mouse exosomal RNA to human mast cells, new mouse proteins were found in the recipient cells, indicating that transferred exosomal mRNA can be translated after entering another cell. In summary, we show that exosomes contain both mRNA and microRNA, which can be delivered to another cell, and can be functional in this new location. We propose that this RNA is called "exosomal shuttle RNA" (esRNA).
10,484 citations
"Exosomes as biomarker treasure ches..." refers background in this paper
...In terms of RNAs, the first study on exosomes was performed in 2007 [28]....
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...By transferring RNAs, exosomes are capable of transferring genetic information that can be translated into functional proteins in target cells [28]....
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TL;DR: This unit describes different approaches for exosome purification from various sources, and discusses methods to evaluate the purity and homogeneity of the purified exosomes preparations.
Abstract: Exosomes are small membrane vesicles found in cell culture supernatants and in different biological fluids. Exosomes form in a particular population of endosomes, called multivesicular bodies (MVBs), by inward budding into the lumen of the compartment. Upon fusion of MVBs with the plasma membrane, these internal vesicles are secreted. Exosomes possess a defined set of membrane and cytosolic proteins. The physiological function of exosomes is still a matter of debate, but increasing results in various experimental systems suggest their involvement in multiple biological processes. Because both cell-culture supernatants and biological fluids contain different types of lipid membranes, it is critical to perform high-quality exosome purification. This unit describes different approaches for exosome purification from various sources, and discusses methods to evaluate the purity and homogeneity of the purified exosome preparations.
4,492 citations
"Exosomes as biomarker treasure ches..." refers background in this paper
...Exosomes 50–150 CD9, CD63, CD81, CD82, annexins, and RAB proteins PCA3, TMPRSS2:ERG Merocrine Antigen presentation, immune regulatory, and metastatic activity [10,45,67,68]...
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TL;DR: The physical properties that define exosomes as a specific population of secreted vesicles are described, their biological effects, particularly on the immune system, are summarized, and the potential roles that secretedvesicles could have as intercellular messengers are discussed.
Abstract: Exosomes are small membrane vesicles of endocytic origin that are secreted by most cells in culture. Interest in exosomes has intensified after their recent description in antigen-presenting cells and the observation that they can stimulate immune responses in vivo. In the past few years, several groups have reported the secretion of exosomes by various cell types, and have discussed their potential biological functions. Here, we describe the physical properties that define exosomes as a specific population of secreted vesicles, we summarize their biological effects, particularly on the immune system, and we discuss the potential roles that secreted vesicles could have as intercellular messengers.
4,380 citations
"Exosomes as biomarker treasure ches..." refers background in this paper
...Their discovery in sheep reticulocyte maturation gave rise to the idea that exosomes may function as a trash bin for unnecessary and redundant proteins and therefore could be an alternative pathway for lysosomal degradation [22]....
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TL;DR: Tumour-derived microvesicles may provide diagnostic information and aid in therapeutic decisions for cancer patients through a blood test by incorporating an mRNA for a reporter protein into them, and it is demonstrated that messages delivered by microvesicle are translated by recipient cells.
Abstract: Glioblastoma tumour cells release microvesicles (exosomes) containing mRNA, miRNA and angiogenic proteins. These microvesicles are taken up by normal host cells, such as brain microvascular endothelial cells. By incorporating an mRNA for a reporter protein into these microvesicles, we demonstrate that messages delivered by microvesicles are translated by recipient cells. These microvesicles are also enriched in angiogenic proteins and stimulate tubule formation by endothelial cells. Tumour-derived microvesicles therefore serve as a means of delivering genetic information and proteins to recipient cells in the tumour environment. Glioblastoma microvesicles also stimulated proliferation of a human glioma cell line, indicating a self-promoting aspect. Messenger RNA mutant/variants and miRNAs characteristic of gliomas could be detected in serum microvesicles of glioblastoma patients. The tumour-specific EGFRvIII was detected in serum microvesicles from 7 out of 25 glioblastoma patients. Thus, tumour-derived microvesicles may provide diagnostic information and aid in therapeutic decisions for cancer patients through a blood test.
4,118 citations
TL;DR: This work speculates on the reasons behind this large discrepancy between the expectations arising from proteomics and the realities of clinical diagnostics and suggests approaches by which protein-disease associations may be more effectively translated into diagnostic tools in the future.
4,062 citations
"Exosomes as biomarker treasure ches..." refers background in this paper
...The detection sensitivity can increase approximately 100fold by combining these two methods; however, it is still not enough to identify the low-abundance markers [8]....
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