Dark side of the exosome: the role of the exosome in cancer metastasis and targeting the exosome as a strategy for cancer therapy

The Role of Extracellular Vesicles in the Treatment of Prostate Cancer

Prostate cancer (PCa) has become a public health concern in elderly men due to an ever-increasing number of estimated cases. Unfortunately, the available treatments are unsatisfactory because of a lack of a durable response, especially in advanced disease states. Extracellular vesicles (EVs) are lipid-bilayer encircled nanoscale vesicles that carry numerous biomolecules (e.g., nucleic acids, proteins, and lipids), mediating the transfer of information. The past decade has witnessed a wide range of EV applications in both diagnostics and therapeutics. First, EV-based non-invasive liquid biopsies provide biomarkers in various clinical scenarios to guide treatment; EVs can facilitate the grading and staging of patients for appropriate treatment selection. Second, EVs play a pivotal role in pathophysiological processes via intercellular communication. Targeting key molecules involved in EV-mediated tumor progression (e.g., proliferation, angiogenesis, metastasis, immune escape, and drug resistance) is a potential approach for curbing PCa. Third, EVs are promising drug carriers. Naïve EVs from various sources and engineered EV-based drug delivery systems have paved the way for the development of new treatment modalities. This review discusses the recent advancements in the application of EV therapies and highlights EV-based functional materials as novel interventions for PCa.

Harnessing exosomes as cancer biomarkers in clinical oncology

Exosomes are extracellular vesicles well known for facilitating cell-to-cell communication by distributing essential macromolecules like proteins, DNA, mRNA, lipids, and miRNA. These vesicles are abundant in fluids distributed throughout the body, including urine, blood, saliva, and even bile. They are important diagnostic tools for breast, lung, gastrointestinal cancers, etc. However, their application as cancer biomarkers has not yet been implemented in most parts of the world. In this review, we discuss how OMICs profiling of exosomes can be practiced by substituting traditional imaging or biopsy methods for cancer detection. Previous methods like extensive imaging and biopsy used for screening were expensive, mostly invasive, and could not easily provide early detection for various types of cancer. Exosomal biomarkers can be utilized for routine screening by simply collecting body fluids from the individual. We anticipate that the use of exosomes will be brought to light by the success of clinical trials investigating their potential to enhance cancer detection and treatment in the upcoming years.

Small extracellular vesicles from irradiated lung epithelial cells promote the activation of fibroblasts in pulmonary fibrosis

BACKGROUND

Alveolar epithelial injury and dysfunction are the risk factors for radiation-induced pulmonary fibrosis (RIPF). However, it is not clear about the relationship between RIPF and the small extracellular vesicles (sEV) secreted by irradiated alveolar epithelial cells. Based on the activation of fibroblasts, this study explored the role of sEV derived from alveolar epithelial cells in RIPF and the potential mechanisms.

METHODS

Transmission electron microscopy (TEM), nanoparticle tracking analysis (NTA), and western blotting were used to characterize sEV. Western blotting was used to detect fibrosis-associated proteins. Cell counts and transwell assays were used to evaluate the proliferation and migration ability of fibroblasts. RT-PCR was used to observe the extracellular matrix (ECM) synthesized by fibroblasts, miRNA changes in the sEV were determined by second-generation sequencing.

RESULTS

TEM, NTA, and western blotting showed the extracellular vesicles with a double-layer membrane structure of approximately 100 nm in diameter. The sEV derived from irradiated A549, HBEC3-KT, and MLE12 cells upregulated FN1 and alpha-SMA proteins expression in fibroblasts and drove the fibroblast to myofibroblast transition, and the sEV from irradiated mouse bronchoalveolar lavage fluid (BALF) affirmed the same results. In addition, the sEV derived from irradiated alveolar epithelial cells significantly increased the migration ability of fibroblasts and the expression of extracellular matrix proteins such as FN1. The results of miRNA sequencing of sEV in BALF of rats with RIPF showed that the metabolic pathway may be important for miRNA to regulate the activation of fibroblasts.

CONCLUSION

The sEV derived from radiated pulmonary epithelial cells promote the activation, migration and extracellular matrix proteins expression of lung fibroblasts; miRNA in sEV may be an important molecular that affects the activation of lung fibroblasts.

Optimization Protocol of the PEG-Based Method for OSCC-Derived Exosome Isolation and Downstream Applications

The exosome precipitation method affects the purity of the exosome and the quality of the downstream application. Polymer-based precipitation is a cost-effective method widely used in different research fields. The percentage of the polymer should be modified in different cell types or liquid biopsy before precipitation. This study aimed to optimize the protocol of the poly(ethylene glycol) (PEG)-based approach for extracting oral squamous cell carcinoma (OSCC)-derived exosomes, and its downstream applications. We used 8%, 10%, and 12% PEG to isolate the exosomes from the culture medium and compared the purity with that of the ultracentrifugation method. In addition, we extracted exosomal protein, DNA, and RNA, and tested the cell transfection efficiency for downstream application. The results reveal that 8% PEG and the medium mixture incubated at 4 °C overnight effectively precipitated exosomes of higher purity and more proper size and particle numbers compared with the ultracentrifuge method. PEG-precipitated exosomes cocultured with fibroblasts showed better transfection efficiency compared to exosomes alone. Therefore, 8% PEG is ideal for OSCC-derived exosome isolation and downstream applications. We recommend that the cost-effective PEG precipitation method be used for precipitating exosomes from OSCC cell experiments.

Anti-Cancer Role and Therapeutic Potential of Extracellular Vesicles

Cell-cell communication is an important mechanism in biological processes. Extracellular vesicles (EVs), also referred to as exosomes, microvesicles, and prostasomes, are microvesicles secreted by a variety of cells. EVs are nanometer-scale vesicles composed of a lipid bilayer and contain biological functional molecules, such as microRNAs (miRNAs), mRNAs, and proteins. In this review, "EVs" is used as a comprehensive term for vesicles that are secreted from cells. EV research has been developing over the last four decades. Many studies have suggested that EVs play a crucial role in cell-cell communication. Importantly, EVs contribute to cancer malignancy mechanisms such as carcinogenesis, proliferation, angiogenesis, metastasis, and escape from the immune system. EVs derived from cancer cells and their microenvironments are diverse, change in nature depending on the condition. As EVs are thought to be secreted into body fluids, they have the potential to serve as diagnostic markers for liquid biopsy. In addition, cells can encapsulate functional molecules in EVs. Hence, the characteristics of EVs make them suitable for use in drug delivery systems and novel cancer treatments. In this review, the potential of EVs as anti-cancer therapeutics is discussed.

E3 Ubiquitin Ligases in Breast Cancer Metastasis: A Systematic Review of Pathogenic Functions and Clinical Implications

Female breast cancer has become the most commonly occurring cancer worldwide. Although it has a good prognosis under early diagnosis and appropriate treatment, breast cancer metastasis drastically causes mortality. The process of metastasis, which includes cell epithelial–mesenchymal transition, invasion, migration, and colonization, is a multistep cascade of molecular events directed by gene mutations and altered protein expressions. Ubiquitin modification of proteins plays a common role in most of the biological processes. E3 ubiquitin ligase, the key regulator of protein ubiquitination, determines the fate of ubiquitinated proteins. E3 ubiquitin ligases target a broad spectrum of substrates. The aberrant functions of many E3 ubiquitin ligases can affect the biological behavior of cancer cells, including breast cancer metastasis. In this review, we provide an overview of these ligases, summarize the metastatic processes in which E3s are involved, and comprehensively describe the roles of E3 ubiquitin ligases. Furthermore, we classified E3 ubiquitin ligases based on their structure and analyzed them with the survival of breast cancer patients. Finally, we consider how our knowledge can be used for E3s’ potency in the therapeutic intervention or prognostic assessment of metastatic breast cancer.

The therapeutic triad of extracellular vesicles: As drug targets, as drugs, and as drug carriers

Rapidly growing interest in the study of extracellular vesicles (EVs) has led to the accumulation of evidence on their critical roles in various pathologies, as well as opportunities to design novel therapeutic EV-based applications. Efficiently exploiting the constantly expanding knowledge of the biology and function of EVs requires a deep understanding of the various possible strategies of using EVs for therapeutic purposes. Accordingly, in the present work, we have narrowed the broad therapeutic potential of EVs and consider the similarities and differences of various strategies as we articulate three major aspects (i.e., a triad) of their therapeutic uses: (i) EVs as drug targets, whereby we discuss therapeutic targeting of disease-promoting EVs; (ii) EVs as drugs, whereby we consider the natural medicinal properties of EVs and the available options for their optimization; and (iii) EVs as drug carriers, whereby we highlight the advantages of EVs as vehicles for efficacious drug delivery of natural compounds. Finally, after conducting a comprehensive review of the latest literature on each of these aspects, we outline opportunities, limitations, and potential solutions.

Involvement of epithelia-derived exosomes in chronic respiratory diseases

Exosomes are tiny membrane lipid bilayer vesicles (φ40-100 nm) formed by the fusion of multivesicular bodies with plasma membrane, which are released extracellular by exocytosis. As natural nanocarriers, exosomes contain a variety of signal substances of the mother cell: nucleic acids, proteins and lipids, etc., which always play a vital role in the transmission of signal molecules between different cells. Epithelial cells are the first-line defense system against various inhaled allergens causing chronic respiratory diseases (CRD), such as asthma and chronic obstructive pulmonary disease (COPD). It's noted that increasing literature shows the exosomes derived from epithelial cells are involved in the pathogenesis of CRD. Moreover, the correlations between exosome cargo and the disease phenotypes show a high potential of using exosomes as biomarkers of CRD. In this review, we mainly focus on the physiological functions of epithelial-derived exosomes and illustrate the involved mechanism of epithelial-derived exosomes in common CRD.

The Roles of MicroRNAs and Extracellular Vesicles in the Pathogeneses of Idiopathic Pulmonary Fibrosis and Acute Respiratory Distress Syndrome

The lungs are the organs that work for gas exchange. The basic structure of the lungs is an alveolus, which consists of various types of parenchymal cells and bone marrow-derived cells. Therefore, because the lungs consist of various types of cells with various functions, communication among the different types of the cells should play important roles for the homeostasis and response to disease pathogens. In the past decades, researchers have focused on cytokines or adhesion molecules to reveal the intercellular communication for understanding the homeostasis and pathogenesis in the lungs. Recent investigations have revealed that an extracellular vesicle can move among cells for transferring substances including microRNAs in the vesicles as an intercellular messenger. MicroRNAs and extracellular vesicles are therefore attracting increasing attention from both translational and clinical researchers because these emerging intercellular communication tools seem to be useful for further understanding of the disease pathogenesis as well as the biomarkers for diagnosis and prognosis of the diseases including cancer and inflammatory diseases. This review article is an attempt to review studies about microRNAs and extracellular vesicles in terms of their roles in normal conditions and refractory diseases of the lungs such as idiopathic pulmonary fibrosis and acute respiratory distress syndrome including our recent study about pulmonary microvascular endothelial microparticles particles as the biomarker for diagnosis and prognosis of acute respiratory distress syndrome. This review also addresses the possibility of microRNAs and extracellular vesicles as new clinical tools for the diagnosis or treatment for these refractory respiratory diseases.

Extracellular vesicles: Their emerging roles in the pathogenesis of respiratory diseases

Alveoli are the basic structure of the lungs, consisting of various types of parenchymal and bone marrow-derived cells including alveolar macrophages. These various types of cells have several important functions; thus, communication between these cells plays an important role in homeostasis as well as in the pathophysiology of diseases in the lungs. For a better understanding of the pathophysiology of lung diseases, researchers have isolated each type of lung cell to investigate the changes in their gene expressions, including their humoral factor or adhesion molecules, to reveal the intercellular communication among these cells. In particular, investigations during the past decade have focused on extracellular vesicles, which are lipid bilayer delimited vesicles released from a cell that can move among various cells and transfer substances, including microRNAs, mRNAs and proteins, thus, functioning as intercellular messengers. Extracellular vesicles can be classified into three general groups: apoptotic bodies, exosomes, and microparticles. Extracellular vesicles, especially exosomes and microparticles, are attracting increasing attention from pulmonologists as tools for understanding pathogenesis and disease diagnosis. Here, we review studies, including our own, on exosomes and microparticles and their roles in both lung homeostasis and the pathogenesis of lung diseases such as idiopathic pulmonary fibrosis, chronic obstructive lung diseases, and acute respiratory distress syndrome. This review also addresses the roles of extracellular vesicles in COVID-19, the current global public health crisis.

Exosomes and extracellular vesicles: Rethinking the essential values in cancer biology

Extracellular vesicles (EVs) such as exosomes are released by all living cells and contain diverse bioactive molecules, including nucleic acids, proteins, lipids, and metabolites. Accumulating evidence of EV-related functions has revealed that these tiny vesicles can mediate specific cell-to-cell communication. Within the tumor microenvironment, diverse cells are actively interacting with their surroundings via EVs facilitating tumor malignancy by regulating malignant cascades including angiogenesis, immune modulation, and metastasis. This review summarizes the recent studies of fundamental understandings of EVs from the aspect of EV heterogeneity and highlights the role of EVs in the various steps from oncogenic to metastatic processes. The recognition of EV subtypes is necessary to identify which pathways can be affected by EVs and which subtypes can be targeted in therapeutic approaches or liquid biopsies.

Long-chain polyunsaturated omega-3 fatty acids reduce multiple myeloma exosome-mediated suppression of NK cell cytotoxicity

BACKGROUND

Despite the advances in the treatment of multiple myeloma (MM), complete remission is usually challenging. The interactions between tumor and host cells, in which exosomes (EXs) play critical roles, have been shown to be among the major deteriorative tumor-promoting factors herein. Therefore, any endeavor to beneficially target these EX-mediated interactions could be of high importance.

OBJECTIVES

a) To investigate the effects of myeloma EXs on natural killer (NK) cell functions. b) To check whether treatment of myeloma cells with eicosapentaenoic acid (EPA) or docosahexaenoic acid (DHA), two polyunsaturated omega-3 fatty acids with known anti-cancer effects, can modify myeloma EXs in terms of their effects on natural killer functions.

METHODS

L363 cells were treated with either EPA or DHA or left untreated and the released EXs (designated as E-EX, D-EX and C-EX, respectively) were used to treat NK cells for functional studies.

RESULTS

Myeloma EXs (C-EXs) significantly reduced NK cytotoxicity against K562 cells (P ≤ 0.05), while the cytotoxicity suppression was significantly lower (P ≤ 0.05) in the (E-EX)- and (D-EX)-treated NK cells compared to the (C-EX)-treated cells. The expression of the activating NK receptor NKG2D and NK degranulation, after treatment with the EXs, were both altered following the same pattern. However, C-EXs could increase IFN-γ production in NK cells (P < 0.01), which was not significantly affected by EPA/DHA treatment. This indicates a dual effect of myeloma EXs on NK cells functions.

CONCLUSION

Our observations showed that myeloma EXs have both suppressive and stimulatory effects on different NK functions. Treatment of myeloma cells with EPA/DHA can reduce the suppressive effects of myeloma EXs while maintaining their stimulatory effects. These findings, together with the previous findings on the anti-cancer effects of EPA/DHA, provide stronger evidence for the repositioning of the currently existing EPA/DHA supplements to be used in the treatment of MM as an adjuvant treatment. EXs released from L363 (myeloma) cells in their steady state increase IFN-γ production of NK cells, while reduce their cytotoxicity against the K562 cell line (right blue trace). EXs from L363 cells pre-treated with either EPA or DHA are weaker stimulators of IFN-γ production. These EXs also increase NK cytotoxicity and NKG2D expression (left brown trace) compared to the EXs obtained from untreated L363 cells. Based on these findings, myeloma EXs have both suppressive and stimulatory effects on different NK functions depending on the properties of their cells of origin, which can be exploited in the treatment of myeloma.

DUSP2 regulates extracellular vesicle-VEGF-C secretion and pancreatic cancer early dissemination

Early dissemination is a unique characteristic and a detrimental process of pancreatic ductal adenocarcinoma (PDAC); however, the underlying mechanism remains largely unknown. Here, we investigate the role of dual-specificity phosphatase-2 (DUSP2)-vascular endothelial growth factor-C (VEGF-C) axis in mediating PDAC lymphangiogenesis and lymphovascular invasion. Expression of DUSP2 is greatly suppressed in PDAC, which results in increased aberrant expression of extracellular vesicle (EV)-associated VEGF-C secretion. EV-VEGF-C exerts paracrine effects on lymphatic endothelial cells and autocrine effects on cancer cells, resulting in the lymphovascular invasion of cancer cells. Tissue-specific knockout of Dusp2 in mouse pancreas recapitulates PDAC phenotype and lymphovascular invasion. Mechanistically, loss-of-DUSP2 enhances proprotein convertase activity and vesicle trafficking to promote the release of the mature form of EV-VEGF-C. Collectively, these findings represent a conceptual advance in understanding pancreatic cancer lymphovascular invasion and suggest that loss-of-DUSP2-mediated VEGF-C processing may play important roles in early dissemination of pancreatic cancer.

Abbreviations: DUSP2: dual-specificity phosphatase-2; VEGF-C: vascular endothelial growth factor-C; EV: extracellular vesicles; PDAC: pancreatic ductal adenocarcinoma; KD: knockdown

Circular RNA expression profiles in extracellular vesicles from the plasma of patients with pancreatic ductal adenocarcinoma

Tumor-derived extracellular vesicles (EVs) and their contents are involved in the development of human malignancies. Circular RNAs (circRNAs), enriched in EVs, can regulate diverse cellular processes by acting as microRNA (miRNA) sponges or through other mechanisms. In the present study, we explored the potential roles of circRNAs in EVs in the development of pancreatic ductal adenocarcinoma (PDAC). First, plasma was obtained from patients with PDAC (n = 8) and healthy volunteers (n = 8), and EVs were isolated by the ultracentrifugation method. Nanoparticle tracking analysis and transmission electron microscopy confirmed the size and form of the isolated EVs. The circRNA expression profiles of EVs were investigated by high-throughput whole transcriptome sequencing. We then further validated the accuracy of the circRNA sequencing data by quantitative real-time PCR analysis using plasma samples and PC cell lines, and subsequently performed bioinformatics analysis to reveal the potential functional roles of the differentially expressed circRNAs and to construct a circRNA-miRNA interaction network to predict the target miRNAs of these circRNAs. Our work provides novel targets for further studies concerning the pathogenesis of PDAC.

Inhibiting exosomal MIC-A and MIC-B shedding of cancer cells to overcome immune escape: new insight of approved drugs

Our knowledge of the role of innate immunity in protecting against cancers has expanded greatly in recent years. An early focus was on the adoptive transfer of natural killer (NK) cells and, although this approach has demonstrated promising results in many patients, a few limitations including immune escape of tumors from cytotoxic killing by NK cells have caused treatment failures. Downregulation of the expression of activating ligands on the surface of cancer cells and prevention of the activity of soluble factors are among the mechanisms employed by cancer cells to overcome NK-mediated immunity. It has become evident that a class of small membranous structures of endosomal origin known as exosomes play a key role in regulating the local tumor microenvironment. Here we hypothesize that exosome secretion by cancer cells, which is greater than that of normal cells, is an important escape mechanism employed by cancer cells. Interruption of exosome release by various inhibitory agents in combination with the adoptive transfer of NK cells may overcome, at least in part, the treatment failures that occur with adoptive NK cell transfer. In this regard, repositioning of approved drugs with previously shown effects on exosome release may be a good strategy to bypass the safety issues of newly identified agents and will also dramatically reduce the huge costs of drug approval process.

Exosomal miR-16-5p as a target for malignant mesothelioma

Malignant mesothelioma (MM) is an asbestos-induced cancer arising on the mesothelial surface of organ cavities. MM is essentially incurable without a means of early diagnosis and no successful standard of care. These facts indicate a deep chasm of knowledge that needs to be filled. Our group recently delved into MM tumor biology from the perspective of exosome-contained microRNAs (miRNAs). We discovered that the most abundant miRNAs in MM cancer exosomes were tumor suppressors, particularly miR-16-5p. This observation lead us to hypothesize that MM cells preferentially secreted tumor-suppressor miRNAs via exosomes. Through separate avenues of potential therapeutic advance, we embarked on an innovative strategy to kill MM tumor cells. We employed small molecule inhibitors to block exosome secretion, thereby reducing miR-16-5p exosome loss and replenishing cellular miR-16-5p leading to reduced tumorigenic capacity and miR-16-5p target oncoproteins CCND1 and BCL2. Additionally, we force-fed MM tumor exosomes back to MM tumor cells, which led to cell death, and a reduction in the same oncoproteins. We recapitulated these results with direct transfection of miR-16-5p, confirmed that this is a cancer-cell specific effect, and elucidated a part of the miR-16-5p mechanism of exosome loading.

The emerging role of exosomes in multiple myeloma

Multiple myeloma (MM), one of the most prevalent hematological malignancies, accounts for approximately 10% of all blood cancers. In spite of the recent advancements in MM therapy, this malignancy of terminally differentiated plasma cells (PCs) continues to remain a hard-to-cure disease due to the emergence of drug resistance and frequent relapses. It is now well-established that the tumor-supportive involvement of the bone marrow microenvironment (BMM) including the cellular and non-cellular elements are the major causes behind treatment failures of MM as well as its main complications such as osteolytic bone loss. Exosomes (EXs) are membranous structures that carry signaling molecules and have recently received a great deal of attention as important mediators of inter-cellular communication in health and disease. EXs involve in the growth and drug resistance of many tumors via delivering their rich contents of bioactive molecules including miRNAs, growth factors, cytokines, signaling molecules, etc. With regard to MM, many studies have reported that EXs are among the main culprits playing key roles in the vicious network within the BMM of these patients. The main producers of EXs that largely contribute to MM pathogenesis are bone marrow stromal cells (BMSCs) as well as MM cells themselves. These cell types produce large amounts of EXs that affect a variety of target cells including natural killer (NK) cells, osteoclasts (OCs) and osteoblasts (OBs) to the advantage of tumor survival and progression. These EXs contain a different profile of proteins and miRNAs from that of EXs obtained from their counterparts in healthy individuals. MM patients exhibit distinguishable elevations in some of their contents such as miR-21, miR-146a, let-7b and miR-18a, while some molecules like miR-15a are markedly downregulated in EXs of MM patients compared to healthy individuals. These findings make EXs desirable biomarkers for early prediction of disease progression and drug resistance in the context of MM. On the other hand, due to the tumor-supportive role of EXs, targeting these structures in parallel to the conventional therapeutic regimens may be a promising approach to a successful anti-MM therapy. In the present work, an extensive review of the literature has been carried out to highlight the recent advances in the field.

Integrated analysis of competing endogenous RNA networks revealing five prognostic biomarkers associated with colorectal cancer

Colorectal cancer (CRC) is a common malignant tumor with high morbidity and mortality around the world. The aim of this study was to determine the genes significantly associated with the overall survival (OS) of CRC patients and predict their function in the competing endogenous RNA (ceRNA) regulation networks. We constructed the lncRNA-miRNA-mRNA networks according to the differentially expressed RNAs from the The Cancer Genome Atlas data sets of 561 CRC patients. Twelve differentially expressed messenger RNAs from the ceRNA networks were selected through a univariate Cox proportional hazards regression. Then, these genes were analyzed by using multivariate Cox proportional hazards stepwise regression to construct a prognostic model in which five genes (tensin 1, clusterin, proteolipid protein 1, epiregulin, and transcription factor Spi-B) were included. The Kaplan-Meier risk survival analysis showed that this five-gene signature independently predicted a 5-year overall survival in CRC patients (P < 0.001). Furthermore, significance was verified according to two irrelevant Gene Expression Omnibus (GEO) data sets (GSE38832 and GSE39582). The verified five-gene model of CRC can be used to predict patient prognosis and will inform postoperational evaluation and follow-up strategies.

Exosomes of pasteurized milk: potential pathogens of Western diseases

Milk consumption is a hallmark of western diet. According to common believes, milk consumption has beneficial effects for human health. Pasteurization of cow's milk protects thermolabile vitamins and other organic compounds including bioactive and bioavailable exosomes and extracellular vesicles in the range of 40-120 nm, which are pivotal mediators of cell communication via systemic transfer of specific micro-ribonucleic acids, mRNAs and regulatory proteins such as transforming growth factor-β. There is compelling evidence that human and bovine milk exosomes play a crucial role for adequate metabolic and immunological programming of the newborn infant at the beginning of extrauterine life. Milk exosomes assist in executing an anabolic, growth-promoting and immunological program confined to the postnatal period in all mammals. However, epidemiological and translational evidence presented in this review indicates that continuous exposure of humans to exosomes of pasteurized milk may confer a substantial risk for the development of chronic diseases of civilization including obesity, type 2 diabetes mellitus, osteoporosis, common cancers (prostate, breast, liver, B-cells) as well as Parkinson's disease. Exosomes of pasteurized milk may represent new pathogens that should not reach the human food chain.

[Cancer stem-like cell-derived exosomes promotes the proliferation and invasion of human umbilical cord blood-derived mesenchymal stem cells]

OBJECTIVE

To investigate the effect of Piwil2-induced cancer stem-like cell (Piwil2-iCSC)-derived exosomes on the proliferation,migration and invasion of human umbilical cord blood-derived mesenchymal stem cells (hucMSCs).

METHODS

Piwil2-iCSC-derived exosomes were isolated by ultracentrifugation and identified using transmission electron microscopy,nanoparticle tracking analysis and Western blotting.Exosome uptake assay was used to identify the pathway that Piwil2-iCSCderived exosomes utilized.HucMSCs were divided into control group,PBS intervention group and exosome intervention group,and CCK-8 assay,wound healing assay,Transwell assay,Western blotting and cell karyotype analysis were used to observe the proliferation,migration,invasion,expression levels of MMP2 and MMP9 proteins,and chromosome structure of hucMSCs.

RESULTS

The diameter of Piwil2-iCSC-derived exosomes ranged from 50 nm to 100 nm,and most of them were oval or spherical capsules rich in CD9,CD63 and Piwil2 proteins.Exosomal uptake assay showed that the exosomes executed theirs functions after entering the cells.Compared with the control cells and PBS-treated cells,hucMSCs treated with the exosomes showed significantly increased number of proliferating cells (P<0.05) with accelerated healing rate (P<0.05 at 24 h;P<0.01 at 48 h),increased invasive cells (P<0.01),enhanced protein expressions of MMP2(P<0.05 vs PBS group;P<0.01 vs control group) and MMP9(P<0.05),but their karyotype still remained 46XY without any abnormalities.

CONCLUSIONS

Piwil2-iCSC-derived exosomes can promote the proliferation,migration and invasion but does not cause cancer-like heterogeneity changes in hucMSCs.

Tspan8 and Tspan8/CD151 knockout mice unravel the contribution of tumor and host exosomes to tumor progression

BACKGROUND

The tetraspanins Tspan8 and CD151 promote metastasis, exosomes (Exo) being suggested to be important in the crosstalk between tumor and host. The contribution of Tspan8 and CD151 to host versus tumor-derived exosome (TEX) activities being not defined, we approached the questions using 3-methylcholanthrene-induced (MCA) tumors from wt, Tspan8ko, CD151ko and Tspan8/CD151 (db)ko mice, implanted into tetraspanin-competent and deficient hosts.

METHODS

Tumor growth and dissemination, hematopoiesis and angiogenesis were surveyed in wild type (wt), Tspan8ko, CD151ko and dbko mice bearing tetraspanin-competent and -deficient MCA tumors. In vitro studies using tumor cells, bone marrow cells (BMC) and endothelial cells (EC) elaborated the mechanism of serum (s)Exo- and TEX-induced target modulation.

RESULTS

Tumors grew in autochthonous and syngeneic hosts differing in Tspan8- and/or CD151-competence. However, Tspan8ko- and/or CD151ko-tumor cell dissemination and settlement in metastatic organs was significantly reduced in the autochthonous host, and less severely in the wt-host. Impaired wt-MCA tumor dissemination in the ko-host confirmed a contribution of host- and tumor-Tspan8/-CD151 to tumor cell dissemination, delivery of sExo and TEX being severely impaired by a Tspan8ko/CD151ko. Coculturing tumor cells, BMC and EC with sExo and TEX revealed minor defects in epithelial mesenchymal transition and apoptosis resistance of ko tumors. Strongly reduced migratory and invasive capacity of Tspan8ko/CD151ko-MCA relies on distorted associations with integrins and CAM and missing Tspan8/CD151-promoted recruitment of proteases. The defects, differing between Tspan8ko- and CD151ko-MCA, were rescued by wt-TEX and, less efficiently Tspan8ko- and CD151ko-TEX. Minor defects in hematopoietic progenitor maturation were based on the missing association of hematopoietic growth factors /- receptors with CD151 and, less pronounced, Tspan8. Rescue of impaired angiogenesis in ko mice by wt-sExo and promotion of angiogenesis by TEX depended on the association of Tspan8 and CD151 with GPCR and RTK in EC and tumor cells.

CONCLUSIONS

Tspan8-/CD151-TEX play central roles in tumor progression. Tspan8-/CD151-sExo and TEX contribute by stimulating angiogenesis. Tspan8 and CD151 fulfill these tasks by associating with function-relevant proteins, the additive impact of Tspan8 and CD151 relying on differences in preferred associations. The distinct Tspan8 and CD151 contributions suggest a blockade of TEX-Tspan8 and -CD151 promising for therapeutic intervention.

Modifying exosome release in cancer therapy: How can it help?

The reciprocal interactions of cancer cells with their microenvironment constitute an inevitable aspect of tumor development, progression and response to treatment in all cancers. Such bilateral transactions also serve as the key scenario underlying the development of drug resistance in many cases finally determining the fate of the disease and survival. In this view, a class of extracellular vesicles (EV) known as exosomes (EX) have been shown in the past few years to be important mediators of local and remote cell-to-cell contact changing the activity of their target cells by introducing their content of proteins, non-coding RNAs, and membrane-associated small molecules. In addition to the direct targeting of cancer cells, which has been routinely undertaken by different means to date, parallel attempts to change the signaling network governed by tumor-derived exosomes (TDE) may offer a promising potential to be utilized in cancer therapy. TDE drive diverse functions in the body, most of which have been shown to act to the advantage of tumor progression; however, there are also several studies that report the good aspects of TDE the interruption of which may result in undesirable outcomes. In the present paper, we made an effort to address this important issue by reviewing the very recent literature on different aspects of EX biogenesis and regulation and the various bodily effects of TDE which have been uncovered to date. Moreover, we have reviewed the possible interventions that can be made in TDE release as an important stage of EX biogenesis. Finally, keeping a criticizing view, the advantages and disadvantages of such interventions have been discussed and the future prospect in the field has been outlined.

Malignant ascites-derived exosomes promote proliferation and induce carcinoma-associated fibroblasts transition in peritoneal mesothelial cells

Malignant ascites-derived exosomes have been demonstrated to participate in tumor metastasis. In peritoneal metastasis, normal mesothelial cells (MCs) can be converted into carcinoma-associated fibroblasts (CAFs) by mesothelial-mesenchymal transition (MMT). Herein, we evaluated the effect of malignant ascites-derived exosomes on peritoneal MCs in vitro and in vivo experiments to determine whether exosomes could educate MCs and contribute to peritoneal metastasis.

Under the treatment of ascites-derived exosomes, peritoneal MCs showed increased ability to proliferate and migrate. Expression of CAFs specific proteins markers in MCs, including fibroblast activation protein (FAP), alpha-smooth muscle actin (α-SMA), and fibronectin, were increased after treatment of exosomes. In clinical samples test, TGF-β1 was found to be overexpressed in both malignant ascites and malignant ascites-derived exosomes, and the high volume of TGF-β1 may be responsible for peritoneum fibrosis. In addition, exosomes can increase xenograft tumor growth by suppressing the inhibitive ability on tumor cells by MCs. Besides, CAFs specific proteins markers including FAP, α-SMA, and vimentin were increased in clinical peritoneal biopsies. The immunohistochemical staining for mice tumor biopsies also revealed increased expression of fibronectin and FAP, along with decreased expression of E-cadherin and VCAM-1 after exosomes treatment.

Thus, malignant ascites-derived exosomes may be of importance in the development of peritoneal metastasis by facilitating MCs to proliferate and convert into CAFs by TGF-β1 induced MMT.

Exosomes as emerging players in cancer biology

Oncologic diseases do not behave as isolated entities. Instead, they are based on complex systemic networks involving cell-cell communication between cancerous and healthy cells of the host, which may either facilitate or prevent cancer progression. In addition to cell-cell contacts, cells communicate through secreted factors in a process modulated by ligand concentration, receptor availability and synergy amongst several signaling circuits. Of these secreted factors, exosomes, 30-150 nm membrane vesicles of endocytic origin released by virtually all cells, have emerged as important cell-cell communication players both in physiological and pathological scenarios by being carriers of all the main biomolecules, including lipids, proteins, DNAs, messenger RNAs and microRNA, and performing intercellular transfer of components, locally and systemically. By acting both in tumor and non-tumor cells, such as fibroblasts, leukocytes, endothelial and progenitor cells, tumor- and non-tumor cells-derived exosomes can modulate tumor growth and invasion, tumor-associated angiogenesis, tissue inflammation and the immune system. In this Review, we summarize the main findings of the literature on the roles of exosomes in mediating interactions between tumor and tumor-associated cells. We also discuss how the molecular composition analysis of circulating exosomes in clinical settings has emerged as an attractive non-invasive source of liquid biopsies for early diagnosis, prognosis and follow-up of patients with oncologic diseases.

Quantitative proteomics reveals that distant recurrence-associated protein R-Ras and Transgelin predict post-surgical survival in patients with Stage III colorectal cancer

Surgical resection supplemented with adjuvant chemotherapy is the current preferred treatment for Stage III colorectal cancer (CRC). However, as many as 48% of patients who undergo curative resection eventually suffer from incurable distant recurrence. To investigate the molecular mechanisms involved in Stage III CRC post-surgical distant recurrence, we identified a total of 146 differentially expressed proteins (DEPs) associated with distant recurrence in Stage III CRC using TMT-based quantitative mass spectrometry. Among these DEPs, the altered expressions of R-Ras and Transgelin were then validated in 192 individual specimens using immunohistochemistry (IHC). Furthermore, Kaplan-Meier analysis revealed that the levels of R-Ras and Transgelin were significantly associated with 5-year overall survival (OS) and disease-free survival (DFS), and multivariate Cox-regression analyses revealed that R-Ras and Transgelin were independent prognostic factors for OS and DFS, respectively. In conclusion, this study identified potential biochemical players involved in distant recurrence and indicates that R-Ras and Transgelin are potential post-surgical prognostic biomarkers for Stage III CRC. This proteomics data have been submitted to Proteome Xchange under accession number PXD002903.

CD44/CD44v6 a Reliable Companion in Cancer-Initiating Cell Maintenance and Tumor Progression

Metastasis is the leading cause of cancer death, tumor progression proceeding through emigration from the primary tumor, gaining access to the circulation, leaving the circulation, settling in distant organs and growing in the foreign environment. The capacity of a tumor to metastasize relies on a small subpopulation of cells in the primary tumor, so called cancer-initiating cells (CIC). CIC are characterized by sets of markers, mostly membrane anchored adhesion molecules, CD44v6 being the most frequently recovered marker. Knockdown and knockout models accompanied by loss of tumor progression despite unaltered primary tumor growth unraveled that these markers are indispensable for CIC. The unexpected contribution of marker molecules to CIC-related activities prompted research on underlying molecular mechanisms. This review outlines the contribution of CD44, particularly CD44v6 to CIC activities. A first focus is given to the impact of CD44/CD44v6 to inherent CIC features, including the crosstalk with the niche, apoptosis-resistance, and epithelial mesenchymal transition. Following the steps of the metastatic cascade, we report on supporting activities of CD44/CD44v6 in migration and invasion. These CD44/CD44v6 activities rely on the association with membrane-integrated and cytosolic signaling molecules and proteases and transcriptional regulation. They are not restricted to, but most pronounced in CIC and are tightly regulated by feedback loops. Finally, we discuss on the engagement of CD44/CD44v6 in exosome biogenesis, loading and delivery. exosomes being the main acteurs in the long-distance crosstalk of CIC with the host. In brief, by supporting the communication with the niche and promoting apoptosis resistance CD44/CD44v6 plays an important role in CIC maintenance. The multifaceted interplay between CD44/CD44v6, signal transducing molecules and proteases facilitates the metastasizing tumor cell journey through the body. By its engagement in exosome biogenesis CD44/CD44v6 contributes to disseminated tumor cell settlement and growth in distant organs. Thus, CD44/CD44v6 likely is the most central CIC biomarker.

Disruption of Circulating Extracellular Vesicles as a Novel Therapeutic Strategy against Cancer Metastasis

Metastasis is the main cause of cancer mortality for many types of cancer; however, difficulties remain in effectively preventing metastasis. It has been recently and widely reported that cancer-derived extracellular vesicles (EVs) contribute to cancer metastasis. Thus, therapeutic strategies targeting cancer-derived EVs hold great promise because of the possibility of EVs driving the cancer microenvironment toward metastasis. Here, we provide a novel strategy for therapeutic antibody treatment to target cancer-derived EVs and inhibit the metastasis of breast cancer in a mouse model, establishing a rationale for further clinical investigation. Treatment with human-specific anti-CD9 or anti-CD63 antibodies significantly decreased metastasis to the lungs, lymph nodes, and thoracic cavity, although no obvious effects on primary xenograft tumor growths were observed. In in vitro and in vivo experiments, the EVs incubated with the targeted antibodies were preferentially internalized by macrophages, suggesting that antibody-tagged cancer-derived EVs would be eliminated by macrophages. Our results suggested that therapeutic antibody administration effectively suppresses EV-triggered metastasis in cancer and that the removal of EVs could be a novel strategy for cancer therapy.

Extracellular Vesicles in Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) is characterized by the progression of irreversible airflow limitation and is a leading cause of morbidity and mortality worldwide. Although several crucial mechanisms of COPD pathogenesis have been studied, the precise mechanism remains unknown. Extracellular vesicles (EVs), including exosomes, microvesicles, and apoptotic bodies, are released from almost all cell types and are recognized as novel cell–cell communication tools. They have been shown to carry and transfer a wide variety of molecules, such as microRNAs, messenger RNAs, and proteins, which are involved in physiological functions and the pathology of various diseases. Recently, EVs have attracted considerable attention in pulmonary research. In this review, we summarize the recent findings of EV-mediated COPD pathogenesis. We also discuss the potential clinical usefulness of EVs as biomarkers and therapeutic agents for the treatment of COPD.

Exosomes Promote Ovarian Cancer Cell Invasion through Transfer of CD44 to Peritoneal Mesothelial Cells

Epithelial ovarian cancer (EOC) cells metastasize within the peritoneal cavity and directly encounter human peritoneal mesothelial cells (HPMC) as the initial step of metastasis. The contact between ovarian cancer cells and the single layer of mesothelial cells involves direct communications that modulate cancer progression but the mechanisms are unclear. One candidate mediating cell-cell communications is exosomes, 30-100 nm membrane vesicles of endocytic origin, through the cell-cell transfer of proteins, mRNAs, or microRNAs. Therefore, the goal was to mechanistically characterize how EOC-derived exosomes modulate metastasis. Exosomes from ovarian cancer cells were fluorescently labeled and cocultured with HPMCs which internalized the exosomes. Upon exosome uptake, HPMCs underwent a change in cellular morphology to a mesenchymal, spindle phenotype. CD44, a cell surface glycoprotein, was found to be enriched in the cancer cell-derived exosomes, transferred, and internalized to HPMCs, leading to high levels of CD44 in HPMCs. This increased CD44 expression in HPMCs promoted cancer invasion by inducing the HPMCs to secrete MMP9 and by cleaning the mesothelial barrier for improved cancer cell invasion. When CD44 expression was knocked down in cancer cells, exosomes had fewer effects on HPMCs. The inhibition of exosome release from cancer cells blocked CD44 internalization in HPMCs and suppressed ovarian cancer invasion. In ovarian cancer omental metastasis, positive CD44 expression was observed in those mesothelial cells that directly interacted with cancer cells, whereas CD44 expression was negative in the mesothelial cells remote from the invading edge. This study indicates that ovarian cancer-derived exosomes transfer CD44 to HPMCs, facilitating cancer invasion.

IMPLICATIONS

Mechanistic insight from the current study suggests that therapeutic targeting of exosomes may be beneficial in treating ovarian cancer. Mol Cancer Res; 15(1); 78-92. ©2016 AACR.

Serum extracellular vesicular miR-21-5p is a predictor of the prognosis in idiopathic pulmonary fibrosis

Background

Idiopathic pulmonary fibrosis (IPF) is a disease with a poor prognosis. Although the median survival is 3 years, the clinical course varies to a large extent among IPF patients. To date, there has been no definitive prognostic marker. Extracellular vesicles (EVs) are known to hold nucleic acid, including microRNAs, and to regulate gene expression in the recipient cells. Moreover, EVs have been shown to express distinct surface proteins or enveloped microRNAs depending on the parent cell or pathological condition. We aimed to identify serum EV microRNAs that would be prognostic for IPF.

Methods

To determine target microRNAs in IPF, we measured serum EV microRNA expression profiles using microRNA PCR arrays in a bleomycin mouse model and validated the microRNAs in additional mice using RT-PCR. Secondly, we enrolled 41 IPF patients and conducted a 30-month prospective cohort study. Expression of serum EV miR-21-5p was normalized by dividing by the EV amount. The relative amount of EVs was measured using the ExoScreen method. We calculated the correlations between baseline serum EV miR-21-5p expression and other clinical variables. Furthermore, we determined if serum EV miR-21-5p can predict mortality during 30 months using the Cox hazard model. According to the median level, we divided the IPF patients into two groups. Then we compared the survival rate during 30 months between the two groups using the Kaplan-Meier method.

Results

Serum EV miR-21-5p was elevated in both the acute inflammatory phase (day 7) and the chronic fibrotic phase (day 28) in the mouse model. In the clinical setting, serum EV miR-21-5p was significantly higher in IPF patients than in healthy control subjects. The baseline serum EV miR-21-5p was correlated with the rate of decline in vital capacity over 6 months. Furthermore, serum EV miR-21-5p was independently associated with mortality during the following 30 months, even after adjustment for other variables. In the survival analysis, IPF patients whose baseline serum EV miR-21-5p was high had a significantly poorer prognosis over 30 months.

Conclusions

Our results suggest that serum EV miR-21-5p has potential as a prognostic biomarker for IPF.

Electronic supplementary material

The online version of this article (doi:10.1186/s12931-016-0427-3) contains supplementary material, which is available to authorized users.

Exosome-like vesicles in uterine aspirates: a comparison of ultracentrifugation-based isolation protocols

Background

Uterine aspirates are used in the diagnostic process of endometrial disorders, yet further applications could emerge if its complex milieu was simplified. Exosome-like vesicles isolated from uterine aspirates could become an attractive source of biomarkers, but there is a need to standardize isolation protocols. The objective of the study was to determine whether exosome-like vesicles exist in the fluid fraction of uterine aspirates and to compare protocols for their isolation, characterization, and analysis.

Methods

We collected uterine aspirates from 39 pre-menopausal women suffering from benign gynecological diseases. The fluid fraction of 27 of those aspirates were pooled and split into equal volumes to evaluate three differential centrifugation-based procedures: (1) a standard protocol, (2) a filtration protocol, and (3) a sucrose cushion protocol. Characterization of isolated vesicles was assessed by electron microscopy, nanoparticle tracking analysis and immunoblot. Specifically for RNA material, we evaluate the effect of sonication and RNase A treatment at different steps of the protocol. We finally confirmed the efficiency of the selected methods in non-pooled samples.

Results

All protocols were useful to isolate exosome-like vesicles. However, the Standard procedure was the best performing protocol to isolate exosome-like vesicles from uterine aspirates: nanoparticle tracking analysis revealed a higher concentration of vesicles with a mode of 135 ± 5 nm, and immunoblot showed a higher expression of exosome-related markers (CD9, CD63, and CD81) thus verifying an enrichment in this type of vesicles. RNA contained in exosome-like vesicles was successfully extracted with no sonication treatment and exogenous nucleic acids digestion with RNaseA, allowing the analysis of the specific inner cargo by Real-Time qPCR.

Conclusion

We confirmed the existence of exosome-like vesicles in the fluid fraction of uterine aspirates. They were successfully isolated by differential centrifugation giving sufficient proteomic and transcriptomic material for further analyses. The Standard protocol was the best performing procedure since the other two tested protocols did not ameliorate neither yield nor purity of exosome-like vesicles. This study contributes to establishing the basis for future comparative studies to foster the field of biomarker research in gynecology.

Electronic supplementary material

The online version of this article (doi:10.1186/s12967-016-0935-4) contains supplementary material, which is available to authorized users.

Application of a Persistent Heparin Treatment Inhibits the Malignant Potential of Oral Squamous Carcinoma Cells Induced by Tumor Cell-Derived Exosomes

Exosomes are 30–100 nm-sized membranous vesicles, secreted from a variety of cell types into their surrounding extracellular space. Various exosome components including lipids, proteins, and nucleic acids are transferred to recipient cells and affect their function and activity. Numerous studies have showed that tumor cell-derived exosomes play important roles in tumor growth and progression. However, the effect of exosomes released from oral squamous cell carcinoma (OSCC) into the tumor microenvironment remains unclear. In the present study, we isolated exosomes from OSCC cells and investigated the influence of OSCC cell-derived exosomes on the tumor cell behavior associated with tumor development. We demonstrated that OSCC cell-derived exosomes were taken up by OSCC cells themselves and significantly promoted proliferation, migration, and invasion through the activation of the PI3K/Akt, MAPK/ERK, and JNK-1/2 pathways in vitro. These effects of OSCC cell-derived exosomes were obviously attenuated by treatment with PI3K, ERK-1/2, and JNK-1/2 pharmacological inhibitors. Furthermore, the growth rate of tumor xenografts implanted into nude mice was promoted by treatment with OSCC cell-derived exosomes. The uptake of exosomes by OSCC cells and subsequent tumor progression was abrogated in the presence of heparin. Taken together, these data suggest that OSCC cell-derived exosomes might be a novel therapeutic target and the use of heparin to inhibit the uptake of OSCC-derived exosomes by OSCC cells may be useful for treatment.

Decoding the Secret of Cancer by Means of Extracellular Vesicles

One of the recent outstanding developments in cancer biology is the emergence of extracellular vesicles (EVs). EVs, which are small membrane vesicles that contain proteins, mRNAs, long non-coding RNAs, and microRNAs (miRNAs), are secreted by a variety of cells and have been revealed to play an important role in intercellular communications. These molecules function in the recipient cells; this has brought new insight into cell-cell communication. Recent reports have shown that EVs contribute to cancer cell development, including tumor initiation, angiogenesis, immune surveillance, drug resistance, invasion, metastasis, maintenance of cancer stem cells, and EMT phenotype. In this review, I will summarize recent studies on EV-mediated miRNA transfer in cancer biology. Furthermore, I will also highlight the possibility of novel diagnostics and therapy using miRNAs in EVs against cancer.

microRNAs as pharmacogenomic biomarkers for drug efficacy and drug safety assessment

Much evidence has documented that microRNAs (miRNAs) play an important role in the modulation of interindividual variability in the production of drug metabolizing enzymes and transporters (DMETs) and nuclear receptors (NRs) through multidirectional interactions involving environmental stimuli/stressors, the expression of miRNA molecules and genetic polymorphisms. MiRNA expression has been reported to be affected by drugs and miRNAs themselves may affect drug metabolism and toxicity. In cancer research, miRNA biomarkers have been identified to mediate intrinsic and acquired resistance to cancer therapies. In drug safety assessment, miRNAs have been found associated with cardiotoxicity, hepatotoxicity and nephrotoxicity. This review article summarizes published studies to show that miRNAs can serve as early biomarkers for the evaluation of drug efficacy and drug safety.

Comparative study of ¹⁸F-FDG-PET/CT imaging and serum hTERT mRNA quantification in cancer diagnosis

We have reported on the clinical usefulness of human telomerase reverse transcriptase (hTERT) mRNA quantification in sera in patients with several cancers. Positron emission tomography–computed tomography (PET/CT) using ¹⁸F-fluorodeoxyglucose (FDG) has recently become an excellent modality for detecting cancer. We performed a diagnostic comparative study of FDG-PET/CT and hTERT mRNA quantification in patients with cancer. Four hundred seventy subjects, including 125 healthy individuals and 345 outpatients with cancer who had received medical treatments for cancer in their own or other hospitals, were enrolled. The subjects were diagnosed by FDG-PET/CT, and we measured their serum hTERT mRNA levels using real-time RT-PCR, correlating the quantified values with the clinical course. In this prospective study, we statistically assessed the sensitivity and specificity, and their clinical significance. hTERT mRNA and FDG-PET/CT were demonstrated to be correlated with the clinical parameters of metastasis and recurrence (P < 0.001), and of recurrence and tumor number in cancer compared with noncancer patients, respectively. A multivariate analysis showed a significant difference in the detection by FDG-PET/CT, ¹⁸F-FDG uptake, the detection by hTERT mRNA, and age. The use of both FDG-PET/CT and hTERT mRNA resulted in a positivity of 94.4% (221/234) for the detection of viable tumor cells. FDG-PET/CT is superior to hTERT mRNA quantification in the early detection of cancer and combinative use of FDG-PET/CT and hTERT mRNA may improve the diagnostic accuracy of cancer.

Exosomes in development, metastasis and drug resistance of breast cancer

Transport through the cell membrane can be divided into active, passive and vesicular types (exosomes). Exosomes are nano-sized vesicles released by a variety of cells. Emerging evidence shows that exosomes play a critical role in cancers. Exosomes mediate communication between stroma and cancer cells through the transfer of nucleic acid and proteins. It is demonstrated that the contents and the quantity of exosomes will change after occurrence of cancers. Over the last decade, growing attention has been paid to the role of exosomes in the development of breast cancer, the most life-threatening cancer in women. Breast cancer could induce salivary glands to secret specific exosomes, which could be used as biomarkers in the diagnosis of early breast cancer. Exosome-delivered nucleic acid and proteins partly facilitate the tumorigenesis, metastasis and resistance of breast cancer. Exosomes could also transmit anti-cancer drugs outside breast cancer cells, therefore leading to drug resistance. However, exosomes are effective tools for transportation of anti-cancer drugs with lower immunogenicity and toxicity. This is a promising way to establish a drug delivery system.

Intercellular Signaling in Cancer-the SMT and TOFT Hypotheses, Exosomes, Telocytes and Metastases: Is the Messenger in the Message?

This review examines the current two leading hypotheses relating to cancer neogenesis—the somatic mutation theory (SMT) and the tissue organization field theory (TOFT)—and focuses on four specific issues.

What are the details of the process that changes the epigenetic cargo of the exosomes a cell produces when it becomes malignant?

Can exosomes produced by a malignant cell induce on their own a metastatic cancer in the target tissue?

What is the functional significance of the fact that exosomes from cancer cells carry in their loads segments of genomic DNA bearing cancer-related mutations across the entire spectrum?

What is the evolutionary advantage for the organism of the production by its cancer cells of exosomes that carry epigenetic instructions for the building of elaborate molecular mechanisms that promote the growth of metastatic cancers?

These issues are examined with a view of determining the support they give to one or other of the two hypotheses. The conclusion is that they support a specific form of TOFT in which exosomes play a key role.

Exosomes Biogenesis and Potentials in Disease Diagnosis and Drug Delivery

Exosomes were discovered more than 30 years ago. Only recently has their importance been recognized for intercellular communication. Exosomes, with their size ranging from 30 nm to 100 nm, are lipid bilayer nanoparticles and secreted by many different types of cells with versatile functions. Exosomes contain macromolecules and exist in various body fluids, including blood, urine, milk and ascites fluid. Due to their specific property, exosomes are very promising in the fields of disease diagnosis and therapy. Nanotechnology is a great tool that will be helpful in basic research and the application of exosomes. Here, we briefly review the function and potential use of exosomes in nanomedicine.