Oncogenic and Non‐Malignant Pancreatic Exosome Cargo Reveal Distinct Expression of Oncogenic and Prognostic Factors Involved in Tumor Invasion and Metastasis

Exosomes are small extracellular membrane vesicles important in intercellular communication, with their oncogenic cargo attributed to tumor progression and pre‐metastatic niche formation. To gain an insight into key differences in oncogenic composition of exosomes, human non‐malignant epithelial and pancreatic cancer cell models and purified and characterized resultant exosome populations are utilized. Proteomic analysis reveals the selective enrichment of known exosome markers and signaling proteins in comparison to parental cells. Importantly, valuable insights into oncogenic exosomes (362 unique proteins in comparison to non‐malignant exosomes) of key metastatic regulatory factors and signaling molecules fundamental to pancreatic cancer progression (KRAS, CD44, EGFR) are provided. It is reported that oncogenic exosomes contain factors known to regulate the pre‐metastatic niche (S100A4, F3, ITGβ5, ANXA1), clinically‐relevant proteins which correlate with poor prognosis (CLDN1, MUC1) as well as protein networks involved in various cancer hallmarks including proliferation (CLU, CAV1), invasion (PODXL, ITGA3), metastasis (LAMP1, ST14) and immune surveillance escape (B2M). The presence of these factors in oncogenic exosomes offers an understanding of select differences in exosome composition during tumorigenesis, potential components as prognostic and diagnostic biomarkers in pancreatic cancer, and highlights the role of exosomes in mediating crosstalk between tumor and stromal cells.     

外泌体在肝纤维化中的作用

外泌体(exosomes)是一种能被大多数细胞分泌的微小膜泡,是具有脂质双层膜结构的细胞外囊泡。现认为外泌体是细胞外囊泡(extracellular vesicles, EVs)的一种亚群。研究表明,外泌体是细胞间信息传递的一种载体。肝脏既可以分泌外泌体,同时也是其他组织细胞产生的外泌体的作用靶点,且肝内与肝外来源的外泌体与肝纤维化的形成、发生、发展均有密切联系。本文主要就外泌体在肝纤维化相关疾病中的作用及外泌体与肝纤维化指标之间的关系进行综述。     

Tumor cell-derived exosomes: A message in a bottle

Exosomes constitute the newest mode of intercellular communication, transmitting information between cells. This exchange of molecular information is facilitated by their unique composition which is enriched with enzymes, structural proteins, adhesion molecules, lipid rafts and RNAs. Following the discovery that cancer cells secrete excessive amounts of exosomes compared to normal cells, it became evident that i) these vesicles can be used as diagnostic markers; ii) their active secretion has functional implications, albeit unknown whether they are tumor promoting or suppressing. Notably, the interplay via the exchange of exosomes between cancer cells and between cancer cells and the tumor stroma may promote the transfer of oncogenes (e.g. β-catenin, CEA, HER2, Melan-A/Mart-1 and LMP-1) and onco-microRNAs (e.g. let7, miR1, miR15, miR16 and miR375) from one cell to another, leading to the reprogramming of the recipient cells. The molecular composition and functional role of tumor cell-derived exosomes in tumorigenesis, metastasis and response to therapy are slowly decrypted and the latest findings as well as potential therapeutic strategies are discussed in this review.     

外泌体在宫颈癌形成及其诊疗中的作用

宫颈癌作为女性第2大恶性肿瘤,仍然是全球范围内的公共卫生问题.外泌体是活细胞主动分泌的一种具有脂质双分子层结构的纳米级囊泡,能够携带蛋白质、脂质、DNA和RNA(包括mRNA、miRNA、lncRNA和circRNA)等多种具有生物学活性的物质.作为新型的细胞间通讯分子,外泌体不仅参与细胞间正常的信息传递和物质交换等生...     

外泌体介导的miRNAs对恶性肿瘤调控作用研究的新进展

外泌体是一种直径为30 nm^100 nm的细胞外脂质囊泡,几乎可以被所有类型的细胞释放,包括癌细胞。作为细胞间通讯的重要介质,宿主细胞或癌细胞分泌的外泌体可以介导包括miRNA、mRNA、DNA片段及蛋白质在内的多种物质参与肿瘤的发生、生长、侵袭及转移过程。尤其是miRNA已经被证实是肿瘤衍生的外泌体用于实现自身功能机制的重要组成部分。因此,外泌体miRNA在调节肿瘤发生发展、侵袭转移、肿瘤免疫应答、肿瘤血管生成及肿瘤耐药方面具有显著功能。本文就外泌体介导的miRNA对肿瘤的相关调控作用作一综述。     

近红外荧光蛋白标记乳腺癌细胞外泌体的构建及鉴定

外泌体(Exosomes)是一种大小为30~100 nm的细胞外膜囊泡,与细胞的生物学功能及细胞间的信号传递有着密切的关系,尤其在癌症的诊断及治疗等领域发挥重要作用。为将外泌体更好地应用于乳腺癌肿瘤传递机制的研究,本文首先通过分子克隆手段将近红外荧光蛋白iRFP682基因和外泌体标记蛋白CD63基因克隆到含腺相关病毒(Adeno-associated virus,AAV)末端倒置重复序列(Inverted repeat terminal,ITR)的质粒载体上,构建融合表达近红外荧光蛋白和CD63蛋白的重组真核表达载体。然后再与辅助质粒共转染AAV-293细胞,包装重组腺相关病毒、纯化测量滴度后用于感染乳腺癌细胞,最后通过荧光筛选出稳定表达近红外荧光蛋白的乳腺癌细胞株。通过对乳腺癌稳定株的分离、纯化及鉴定,最终得到一个新型生物标记物：iRFP682标记的乳腺癌细胞来源的外泌体,为后续研究外泌体在乳腺癌肿瘤微环境中的分布及信号传递提供保障。     

The protein interaction network of extracellular vesicles derived from human colorectal cancer cells

Various mammalian cells including tumor cells secrete extracellular vesicles (EVs), otherwise known as exosomes and microvesicles. EVs are nanosized bilayered proteolipids and play multiple roles in intercellular communication. Although many vesicular proteins have been identified, their functional interrelationships and the mechanisms of EV biogenesis remain unknown. By interrogating proteomic data using systems approaches, we have created a protein interaction network of human colorectal cancer cell-derived EVs which comprises 1491 interactions between 957 vesicular proteins. We discovered that EVs have well-connected clusters with several hub proteins similar to other subcellular networks. We also experimentally validated that direct protein interactions between cellular proteins may be involved in protein sorting during EV formation. Moreover, physically and functionally interconnected protein complexes form functional modules involved in EV biogenesis and functions. Specifically, we discovered that SRC signaling plays a major role in EV biogenesis, and confirmed that inhibition of SRC kinase decreased the intracellular biogenesis and cell surface release of EVs. Our study provides global insights into the cargo-sorting, biogenesis, and pathophysiological roles of these complex extracellular organelles.     

Exosomes and other extracellular vesicles in host–pathogen interactions

An effective immune response requires the engagement of host receptors by pathogen‐derived molecules and the stimulation of an appropriate cellular response. Therefore, a crucial factor in our ability to control an infection is the accessibility of our immune cells to the foreign material. Exosomes—which are extracellular vesicles that function in intercellular communication—may play a key role in the dissemination of pathogen‐ as well as host‐derived molecules during infection. In this review, we highlight the composition and function of exosomes and other extracellular vesicles produced during viral, parasitic, fungal and bacterial infections and describe how these vesicles could function to either promote or inhibit host immunity.     

The critical role of exosomes in tumor biology

Exosomes are a type of extracellular vesicles (diameter, 30-160 nm), which contain multiple proteins, nucleic acids, lipid molecules, and other substances. Most types of cells can secrete exosomes, although the biogenesis, composition, and function is specific to different cell types. Recently, many studies have demonstrated that exosomes play a critical role in tumor development. In this review, we briefly summarize the biogenesis, composition, and function of exosomes. We also discuss the recent advances in the critical role of exosomes in tumor biology with a special focus on their application in tumor diagnosis and treatment.     

Exosomes: endosomal-derived vesicles shipping extracellular messages

Exosomes are membrane vesicles released into the extracellular environment upon exocytic fusion of multivesicular endosomes with the cell surface. They have a particular composition reflecting their origin in endosomes as intraluminal vesicles. In vitro and in vivo studies support the contribution of exosomes to an acellular mode of communication, leading to intercellular transfer of molecules. Exosomes may have regulatory functions in the immune system and their application in cancer immunotherapy is promising. The mechanisms involved in exosome secretion and interaction with target cells are as yet unclear. A better understanding of these mechanisms is also essential to determine the link between exosomes and retroviruses.     

Exosomes: A Bubble Ride for Prions?

In certain cell types, endosomal multivesicular bodies may fuse with the cell surface in an exocytic manner. During this process, the small 50-90-nm-diameter vesicles contained in their lumen are released into the extracellular environment. The released vesicles are called exosomes. Exosome secretion can be used by cells to eject molecules targeted to intraluminal vesicles of multivesicular bodies, but particular cell types exploit exosomes as intercellular communication devices for transfer of proteins and lipids between cells. The molecular composition of exosomes is determined by sorting events within endosomes that occur concomitantly with the generation of intraluminal vesicles. As other raft-associated components, the glycosylphosphatidylinositol-linked prion protein transits through multivesicular bodies. Recent findings in non-neuronal cell models indicate prion protein association with secreted exosomes. Thus, exosomes could constitute vehicles for transmission of the infectious prion protein, bypassing cell-cell contact in the dissemination of prions.     

Stomatin is highly expressed in exosomes of different origin and is a promising candidate as an exosomal marker

Proteins involved in the organizing of lipid rafts can be found in exosomes, as shown for caveolin‐1, and they could contribute to exosomal cargo sorting, as shown for flotillins. Stomatin belongs to the same stomatin/prohibitin/flotillin/HflK/C family of lipid rafts proteins, but it has never been studied in exosomes except for extracellular vesicles (EVs) originating from blood cells. Here we first show the presence of stomatin in exosomes produced by epithelial cancer cells (non–small cell lung cancer, breast, and ovarian cancer cells) as well as in EVs from biological fluids, including blood plasma, ascitic fluids, and uterine flushings. A high abundance of stomatin in EVs of various origins and its enrichment in exosomes make stomatin a promising exosomal marker. Comparison with other lipid raft proteins and exosomal markers showed that the level of stomatin protein in exosomes from different sources corresponds well to that of CD9, while it differs essentially from flotillin‐1 and flotillin‐2 homologs, which in turn are present in exosomes in nearly equal proportions. In contrast, the level of vesicular caveolin‐1 as well as its EV‐to‐cellular ratio vary drastically depending on cell type.     

Transferring intercellular signals and traits between cancer cells: extracellular vesicles as “homing pigeons”

Extracellular vesicles are cell-derived vesicles, which can transport various cargos out of cells. From their cell of origin, the content molecules (proteins, non-coding RNAs including miRNAs, DNA and others) can be delivered to neighboring or distant cells and as such extracellular vesicles can be regarded as vehicles of intercellular communication or “homing pigeons”. Extracellular vesicle shuttling is able to actively modulate the tumor microenvironment and can partake in tumor dissemination. In various diseases, including cancer, levels of extracellular vesicle secretion are altered resulting in different amounts and/or profiles of detectable vesicular cargo molecules and these distinct content profiles are currently being evaluated as biomarkers. Apart from their potential as blood-derived containers of specific biomarkers, the transfer of extracellular vesicles to surrounding cells also appears to be involved in the propagation of phenotypic traits. These interesting properties have put extracellular vesicles into the focus of many recent studies.Here we review findings on the involvement of extracellular vesicles in transferring traits of cancer cells to their surroundings and briefly discuss new data on oncosomes, a larger type of vesicle. A pressing issue in cancer treatment is rapidly evolving resistance to many initially efficient drug therapies. Studies investigating the role of extracellular vesicles in this phenomenon together with a summary of the technical challenges that this field is still facing, are also presented. Finally, emerging areas of research such as the analysis of the lipid composition on extracellular vesicles and cutting-edge techniques to visualise the trafficking of extracellular vesicles are discussed.     

Multifaceted effects of oligodendroglial exosomes on neurons: impact on neuronal firing rate,signal transduction and gene regulation

Exosomes are small membranous vesicles of endocytic origin that are released by almost every cell type. They exert versatile functions in intercellular communication important for many physiological and pathological processes. Recently, exosomes attracted interest with regard to their role in cell–cell communication in the nervous system. We have shown that exosomes released from oligodendrocytes upon stimulation with the neurotransmitter glutamate are internalized by neurons and enhance the neuronal stress tolerance. Here, we demonstrate that oligodendroglial exosomes also promote neuronal survival during oxygen–glucose deprivation, a model of cerebral ischaemia. We show the transfer from oligodendrocytes to neurons of superoxide dismutase and catalase, enzymes which are known to help cells to resist oxidative stress. Additionally, we identify various effects of oligodendroglial exosomes on neuronal physiology. Electrophysiological analysis using in vitro multi-electrode arrays revealed an increased firing rate of neurons exposed to oligodendroglial exosomes. Moreover, gene expression analysis and phosphorylation arrays uncovered differentially expressed genes and altered signal transduction pathways in neurons after exosome treatment. Our study thus provides new insight into the broad spectrum of action of oligodendroglial exosomes and their effects on neuronal physiology. The exchange of extracellular vesicles between neural cells may exhibit remarkable potential to impact brain performance.     

Exosome platform for diagnosis and monitoring of traumatic brain injury

We have previously demonstrated the release of membranous structures by cells into their extracellular environment, which are termed exosomes, microvesicles or extracellular vesicles depending on specific characteristics, including size, composition and biogenesis pathway. With activation, injury, stress, transformation or infection, cells express proteins and RNAs associated with the cellular responses to these events. The exosomes released by these cells can exhibit an array of proteins, lipids and nucleic acids linked to these physiologic events. This review focuses on exosomes associated with traumatic brain injury, which may be both diagnostic and a causative factor in the progression of the injury. Based on current data, exosomes play essential roles as conveyers of intercellular communication and mediators of many of the pathological conditions associated with development, progression and therapeutic failures and cellular stress in a variety of pathologic conditions. These extracellular vesicles express components responsible for angiogenesis promotion, stromal remodelling, signal pathway activation through growth factor/receptor transfer, chemoresistance, immunologic activation and genetic exchange. These circulating exosomes not only represent a central mediator of the pro-inflammatory microenvironment linked with secondary brain injury, but their presence in the peripheral circulation may serve as a surrogate for biopsies, enabling real-time diagnosis and monitoring of neurodegenerative progression.     

Nucleic acids in exosomes: Disease markers and intercellular communication molecules

The term “exosomes” is currently used to describe specific vesicular structures of endosomal origin produced by the majority of eukaryotic cells. These natural vesicles have been under study for more than two decades. Nevertheless, a real splash of scientific interest in studies on exosomes took place only during recent years, when the concept of the role and functions of exosomes in multicellular organisms was essentially reconsidered. The major role in this was played by the discovery of exosomal mRNA and miRNA in 2007, which stimulated the idea of regulatory and communicative role of exosomes in the organism and also encouraged considering exosomes and other vesicles as potential biomarkers. The present review summarizes the up to date knowledge on the composition and probable physiological functions of nucleic acids released by different cells as components of exosomes. We also touch upon the problem of using these data in clinical diagnosis.     

Characterization of Human Thymic Exosomes

Exosomes are nanosized membrane-bound vesicles that are released by various cell types and are capable of carrying proteins, lipids and RNAs which can be delivered to recipient cells. Exosomes play a role in intercellular communication and have been described to mediate immunologic information. In this article we report the first isolation and characterization of exosomes from human thymic tissue. Using electron microscopy, particle size determination, density gradient measurement, flow cytometry, proteomic analysis and microRNA profiling we describe the morphology, size, density, protein composition and microRNA content of human thymic exosomes. The thymic exosomes share characteristics with previously described exosomes such as antigen presentation molecules, but they also exhibit thymus specific features regarding surface markers, protein content and microRNA profile. Interestingly, thymic exosomes carry proteins that have a tissue restricted expression in the periphery which may suggest a role in T cell selection and the induction of central tolerance. We speculate that thymic exosomes may provide the means for intercellular information exchange necessary for negative selection and regulatory T cell formation of the developing thymocytes within the human thymic medulla.     

Emerging role of exosome signalling in maintaining cancer stem cell dynamic equilibrium

Cancer stem cells (CSCs) are a small subset of heterogeneous cells existed in tumour tissues or cancer cell lines with self‐renewal and differentiation potentials. CSCs were considered to be responsible for the failure of conventional therapy and tumour recurrence. However, CSCs are not a static cell population, CSCs and non‐CSCs are maintained in dynamic interconversion state by their self‐differentiation and dedifferentiation. Therefore, targeting CSCs for cancer therapy is still not enough,exploring the mechanism of dynamic interconversion between CSCs and non‐CSCs and blocking the interconversion seems to be imperative. Exosomes are 30‐100 nm size in diameter extracellular vesicles (EVs) secreted by multiple living cells into the extracellular space. They contain cell‐state‐specific bioactive materials, including DNA, mRNA, ncRNA, proteins, lipids, etc. with their specific surface markers, such as, CD63, CD81, Alix, Tsg101, etc. Exosomes have been considered as information carriers in cell communication between cancer cells and non‐cancer cells, which affect gene expressions and cellular signalling pathways of recipient cells by delivering their contents. Now that exosomes acted as information carriers, whether they played role in maintaining dynamic equilibrium state between CSCs and non‐CSCs and their mechanism of activity are unknown. This review summarized the current research advance of exosomes’ role in maintaining CSC dynamic interconversion state and their possible mechanism of action, which will provide a better understanding the contribution of exosomes to dedifferentiation and stemness acquisition of non‐CSCs, and highlight that exosomes might be taken as the attractive target approaches for cancer therapeutics.     

Extracellular vesicles – biogenesis,composition, function,uptake and therapeutic applications

Extracellular vesicles are heterogenous, nano-sized, membrane-limited structures which not only represent a specific way of intercellular communication but also endow cells with many capabilities. Apoptotic bodies created during apoptosis, microvesicles shed from the plasma membrane, and exosomes originated inside the cell and released to extracellular space upon fusion with the plasma membrane, they all belong to extracellular vesicles. Extracellular vesicles contain lipids, proteins, and nucleic acids. In this review, we describe their biogenesis, release and uptake by recipient cells, their composition, functions and potential therapeutic and diagnostic applications.