Exosomes in cancer: small vesicular transporters for cancer progression and metastasis, biomarkers in cancer therapeutics

Cancer progression is a polygenic procedure in which the exosomes can function as substantial roles. Exosomes are tiny, phospholipid bilayer membrane nanovesicles of endocytic derivation with a diameter of 40–100 nm. These nanovesicles can transport bioactive molecules containing mRNAs, proteins, DNA fragments, and non-coding RNAs from a donor cell to recipient cells, and cause the alteration in genetic and epigenetic factors and reprogramming of the target cells. Many diverse cell types such as mesenchymal cells, immune cells, and cancer cells can induce the release of exosomes. Increasing evidence illustrated that the exosomes derived from tumor cells might trigger the tumor initiation, tumor cell growth and progression, metastasis, and drug resistance. The secreted nanovesicles of exosomes can play significant roles in cells communicate via shuttling the nucleic acid molecules and proteins to target cells and tissues. In this review, we discussed multiple mechanisms related to biogenesis, load, and shuttle of the exosomes. Also, we illustrated the diverse roles of exosomes in several types of human cancer development, tumor immunology, angiogenesis, and metastasis. The exosomes may act as the promising biomarkers for the prognosis of various types of cancers which suggested a new pathway for anti-tumor therapeutic of these nanovesicles and promoted exosome-based cancer for clinical diagnostic and remedial procedures.


INTRODUCTION
The solid tumors are complicated structures that including the surrounding tumor stroma and cancer cells, which composed of endothelial cells, fibroblasts, and immune cells (Sund & Kalluri, 2009). The surrounding cells are permanently extracting factors that alter the tumor microenvironment (TME) directly or indirectly (Dvorak et al., 2011). A persistent cross-talk among tumor cells and the distant tumor microenvironment have applied as the pivotal tumor growth, and significant targets in antitumoral intervention, and systemic diffusion (Kalluri & Zeisberg, 2006;Swartz et al., 2012). Extracellular vesicles (EVs) have appeared as long-distance communicators; their outcomes in primary tumors can display as systemic effects and contribute to procedures within the circulation by many various kinds of cells. The exosomes pretense a special class of EVs, which released via various kinds of cells (Desrochers, Antonyak & Cerione, 2016;Kowal, Tkach & Théry, 2014;Mathivanan, Ji & Simpson, 2010). Newly evidence represents that the release of exosomes has been detected to play a considerable role between human tumor cells and systemic cell-to-cell relevance in cancers. The exosomes, initially defined through several common traits in reticulocytes three decades ago, containing morphology (a classic ''dish'' or ''cup'' formed in transfer electron microscopy (SEM)), density (1.13-1.19 g/ml), size (30-100 nm in diameter), and determined increased protein markers (TSG101, HSP70, and tetraspanins) (Harding, Heuser & Stahl, 2013). Recent publications illustrated that exosomes are small membrane nanovesicles shaped in multivesicular bodies of endocytic derivation with a diameter of 40-100 nm. Exosomes were primarily considered as the trash bags for elimination of abandoned membrane segments and unwanted molecular fragments from cells, besides the critical task of exosomes in stimulation of immune response is identified as their effect on antigen presentation in the mid-1990s (Raposo et al., 1996). Interestingly, the scholars detected that noncoding RNAs (miRNAs), messenger RNAs (mRNAs), proteins and DNA fragments could be burdened as ''goods'' in extracellular vesicles (EVs) (Balaj et al., 2011). Likewise the exosomes as a nanovesicles were detected to function as ''communication shuttles'' from a donator cells to recipient cells, that could able to re-encode genes of receiver cells, reprogramming of the tumor microenvironment and recruitment to shape a pro-tumorigenic soil, and play a considerable act in the progression, invasion, metastasis, and become insensitive to a drug of cancer (Azmi, Bao & Sarkar, 2013;Balaj et al., 2011;Valadi et al., 2007).
Here we reviewed a new science concerning the function of exosomes as a shuttle in tumorigenesis, emphasizing their biogenesis, component, significant affection, and then considering the potential of exosomes as a novel biomarkers for clinical remedial target diagnosis and prognosis.

EXOSOMES BIOGENESIS, RELEASE, AND UPTAKE
Contrary to the larger microvesicles (MVs), that straightly shed from the cell membrane, the exosomes forming is a specific process that contains four steps: beginning, endocytosis, multivesicular bodies (MVBs) creation, and finally the exosome secretion (Théry, Zitvogel & Amigorena, 2002). Exosomes primarily can shape through the ceramide-induced procedures of inside budding from the late endosome restricted membranes (Trajkovic et al., 2008). The encapsulation of RNA molecules and functional proteins occur through this process. The Multivesicular bodies (MVBs) within the endocytic systems shaped via the budding of an endosome limited membrane into the extracellular milieu of the section by the junction and merge of the MVBs with the cell membrane. The MVBs are either classified as the destroying of cargo in the lysosome or leading to secretion within the extracellular space as exosomes after vesicular cumulation (Février & Raposo, 2004;Trams et al., 1981). The procedures based on the classified of exosomal cargo within the intraluminal vesicles (ILVs) are still not completely understood. Although it has been offered to characterize the exosomes formation and releasing by both endosomal tethering complexes necessitated for transport (ESCRT)-dependent and independent symptoms, however, alternative ways may also exist (Trajkovic et al., 2008). The ESCRT pathway discerns ubiquitination of membrane proteins and promotes their internalization within the multivesicular endosome (Wollert & Hurley, 2010). The mechanism for the microvesicles formation has been illustrated to regulate through the Syndecan heparan sulfate proteoglycans and their cytoplasmic adaptor syntenin (Baietti et al., 2012). The MVB trafficking and the secretion procedure of exosomes may be performed through the outside of exosomes and the microvesicles budding procedure or through multiple compositions of the endocytic machinery, containing the members of the Rab guanosine triphosphatase (GTPase) family (Rab11, Rab 27a, Rab 27b, Rab 35), elevated expression of heparanase, SNARES (soluble NSF attachment receptor), and cytoskeleton regulatory proteins (Azmi, Bao & Sarkar, 2013;Beach et al., 2014;Ostrowski et al., 2010;Pant, Hilton & Burczynski, 2012). A promoted dissemination of exosomes is critically was detected to be triggered via multiple kinds of stress, including alters in PH membrane, oxidative stress, shear stress, hypoxia, thermal alters, and radiation, besides through formation of ceramide, stimulation of sphingomyelinase and following the p53-adjusted protein tumor-suppressor-activated pathway 6 (TSAP6) (Andaloussi et al., 2013;Azmi, Bao & Sarkar, 2013;Hannafon & Ding, 2013;Joanne et al., 2005;Kucharzewska & Belting, 2013;Lespagnol et al., 2008;Parolini et al., 2009;Yu, Harris & Levine, 2006). Exosomes shuttle information to the recipient cells via three major pathways: (1) interaction between receptor-ligand; (2) straight merge with cell membrane; (3) endocytosis through phagocytosis (Fig. 1). Also, there are multiple proteins that can function as specific receptors to activate the uptake of the exosome, containing ICAM-1 for APCs, and Tim 1/4 for B-cells (Miyanishi et al., 2007;Segura et al., 2005).

EXOSOMES STRUCTURE AND COMPOSITION
Exosomes are commonly cup-shaped extracellular small nanovesicles ranging in size from 30 to 100 nm diameter, consist of a phospholipid bilayer comprising membrane proteins that encircles a lumen containing an extensive range of biomolecules including carbohydrates, lipids, small fragments of DNA, mRNAs, proteins, and miRNAs inward to keep them from destruction (De Veirman et al., 2016;Hwang, 2013;Raimondo et al., 2011;Vlassov et al., 2012;Wang et al., 2016).

Protein composition of exosomes
Exosomes from several kinds of cells include a core set of similar proteins upon 4,600 various proteins have been related to these microvesicles, containing proteins from the phospholipid bilayer, endoplasmic reticulum, cytosol, and Golgi apparatus such as the heat shock proteins (HSP60, HSP70, and HSP90), the tetraspanin family (CD63, CD81, CD9, Figure 1 Schematic of exosomes derived cancer cell biogenesis and secretion. Exosomes can secrete through cells while intracellular organs called multivesicular bodies (MVBs) fuse with the plasma membrane. The MVBs formation occurs through invaginations of late endosomes, which increased molecules from the Golgi apparatus (e.g., MHC class II molecules) or the cell surface (e.g., growth factor receptors). Subsequently, exosomes could be enriched in several materials including sphingomyelin, intracellular protein, ceramide, cholesterol, transmembrane receptors, mRNA, and miRNA. The exosomes secreted from human tumor cells can affect the local tumor microenvironment, alter the extracellular matrix, and enhance the angiogenesis, thrombosis and cancer cell proliferation.
Recently 764 miRNAs and 1639 mRNAs have been recognized in these nanovesicles from tissues of various species via a broad range of researches (Gajos-Michniewicz, Duechler & Czyz, 2014). The composition of exosomes differs between various pathological and physiological status and originated cells. Also, the contents of these nanovesicles can discern from the derived cells because of the optional categorized of the cargo within exosomes.

EXOSOME FUNCTION
As a communicator, exosomes can directly shuttle the bioactive molecules among multiple kinds of recipient cells, with results in targeted cellular phenotyping, contained messenger-RNA (mRNA) and microRNA (miRNA) dependent on the shuttle of genetics, and also epigenetic information and lipid trafficking among cells (Azmi, Bao & Sarkar, 2013;Xiang et al., 2009). The existence of exosomes in the circulating body fluids reveals their role in various pathological situations, the instance of infection disease, cardiovascular disease, and progression of neurodegenerative disease (Bang & Thum, 2012;Fleming et al., 2014). The more substantial role of exosomes has been figured out in cancer which leads to tumor growth, angiogenesis, escaping from the immune response, causing tumor cell migration, stimulating normal cells to an invasion, and leading to metastatic colonization into distal tissues (Azmi, Bao & Sarkar, 2013).

METHODS FOR THE ISOLATION AND ANALYSIS OF BIOMARKERS FROM EXOSOMES IN CANCER CELLS AND BODY FLUIDS
Recently, different methods are available for the isolation and discern of exosomes from the distinguished cells under normal and stressed situations, containing nucleic acid (DNA) sequencing, qRT-PCR analysis, western blotting assay, or Enzyme-linked immunosorbent assay (ELISA), which can identify RNA and protein of exosomes, also ultracentrifugation, source gradient ultracentrifugation combined with ultrafiltration centrifugation (SGUUC), commercial kits, magnetic activated cell sorting (MACS) can utilize as another method. To date, the international society for extracellular vesicles (ISEV) can apply for the detection of extracellular vesicles and their functions. Also, western blot and flow cytometry (FCM) are commonly utilized for recognizing of exosomes through discovering particular tetraspanins (for example CD9, CD63, and HSP70). Further, the transmission electron microscopy (TEM) can use for size and shape analysis (Lötvall et al., 2014). The common technique for the isolation of exosomes contains ultracentrifugation, which is often in combination with sucrose density gradients or sucrose cushions to float the relatively low-density exosomes. The ultracentrifugation procedure has multiple disadvantages: The manner is extremely labor-intensive and time-consuming; due to the restrictions of the design of ultracentrifuge rotors one cannot evaluate more than six specimens at a time; the procedure needs a major amount of raw materials; exosome productions are usually low; and vast training of staff is required (Théry et al., 2006;Zeringer et al., 2015). Isolation of exosomes based on size, by the prosperous isolation of exosomes through applying the ultrafiltration methods which are less time-consuming than ultracentrifugation and do not need the usage of the particular tool (Cheruvanky et al., 2007). HPLC (high-performance liquid chromatography)-based protocols could effectively permit the preparation of extremely pure exosomes. However, these methods need appropriative material and are not negligible to scale-up (Lai et al., 2010). Besides, the intricacy is that both body fluids and cell-culture media include an extensive amount of nanoparticles in the identical size range as exosomes. For instance, many miRNAs are included within extracellular protein complexes rather than exosomes (Wang et al., 2010). In addition, volume-excluding polymers such as polyethylene glycols (PEGs) could be used to precipitate exosomes from empirical specimens. The precipitate can be separated applying either low-speed centrifugation or filtration. System Biosciences presents an appropriative reagent called ExoQuick, which can be added to conditioned cell media, urine or serum, which precipitates these nanovesicles (Adams, 1973;Lewis & Metcalf, 1988;Yamamoto et al., 1970). In principle, a preferable resource for special purification of exosomes should be affinity isolation with antibodies to Alix, annexin, CD63, CD81, CD82, CD9, EpCAM, and Rab5. These antibodies could be collected on multiple media, containing microfluidic devices, plates, magnetic beads and chromatography matrices (Chen et al., 2010;Théry et al., 2006).

Role of exosomes in cancerogenesis
As mentioned earlier, the exosomes revealed important roles in cancer progression. The exosomes released by human cancer cells are known as tumor-derived (TD) exosomes. The TD exosomes through autocrine signals can modulate the local growth progression of human cancer cells. The exosomal autocrine signaling pathway is related to kinds of cells and cellular traits, for instance, exosomes separated from gastric cancer cells with high CD97 (epidermal growth factor seven-transmembrane subfamily) expression enhanced cancer cell proliferation and invasion via exosome-mediated MAPK signaling pathway, and exosomal miRNAs may be contributing to induction of the CD97-associated pathway (Li et al., 2015). A mutant epidermal growth factor receptor (EGFRVIII), exists on the membrane of these nanovesicles originated from glioblastoma cells, can trigger cells loss of this mutant form. The integration of EGFRVIII within these cells caused by promotion of anti-apoptotic procedures and an augment in capacity for anchorage-independent growth (Al-Nedawi et al., 2008). On the other hand, the exosomes originated from pancreatic cancer cells enhance Bax expression, however, reduce Bcl-2 expression, cause the leading to cancer cells of the mitochondrial apoptotic pathway (Ristorcelli et al., 2008). This process illustrated that TD exosomes might act pivotal anti-cancer role through triggering apoptosis in several tumors. Accordingly, the determined or beneficial TD exosomes in vivo to their own survival relies on the cellular traits and kinds of the cells, which more research needs to be clarified. Moreover, the bone marrow mesenchymal stromal cells (BM-MSCs)-derived exosomes can support the multiple tumor cell expansion and development in various human cancer cells (Fig. 2).

Figure 2 Exosome recruitment of bone marrow-derived cells.
Exosomes transform the tumor microenvironment (TME) and dispose of distant tissue sites for metastasis. The efficacies of exosomes at distant tumor sites necessitate that exosomes migrate through the blood or lymph. They dispose tissue sites for metastasis or transform the bone marrow (BM) environment, and making a pre-metastatic niche to enhance tumor invasion and development. Thus tumor-derived exosomes can cause recruiting bone marrow-derived cells to the tumor and pre-tumor tissue where they function as cancer development and support the multiple tumor cell expansion and development in various human cancer cells.

Role of exosomes in tumor angiogenesis
The angiogenic procedures induced cancer cell progression can be activated through nutrient reduction, hypoxic, and in addition, inflammatory responses, generally detected in epithelial cell carcinomas. The neovascularization process from preexisting blood vessels associated with promoted endothelial cell proliferation, migration, and budding (Dvorak, 1986;Nazarenko et al., 2010). Vascular endothelial growth factors (VEGF), IL-8, transforming growth factor B (TGF-β), and fibroblast growth factor (FGF) are some of the angiogenic factors that function as endothelial cell proliferation and migration, can be necessary for the induction of tumor angiogenesis. Also, the exosomal miR-92a derived from leukemic cells can regulate integrin α5 to promote migration regulations and proliferation of endothelial cells and tube formation (Umezu et al., 2013). By other research, exosomes originated from melanoma cells including miR-9 were internalized through endothelial cells enhancing angiogenesis and metastasis via activation of the JAK-STAT pathway (Gajos-Michniewicz, Duechler & Czyz, 2014). Another report illustrated that CD-105-positive exosomes act an important role in establishing a niche in the lung Figure 3 Exosomes drive pre-metastatic niche formation. The formation of the pre-metastatic niche is required for organ-specific metastatic tropism. The exosomes can move to the distant location for increasing the formation of pre-metastatic niche. The complementation of angiogenesis and induction of stromal and epithelial cell differentiation can be associated with a pro-tumor environment. Tumor-derived exosomes provide a pre-metastatic niche, through the polarization of tissue macrophage, suppression of dendritic cell maturation, induction of CAF (cancer-associated fibroblasts) via differentiation of fibroblasts to myofibroblasts. This effect can be performed via the mediation of intercellular cross-talk and subsequent adjustment of both local and distant microenvironments in an autocrine and paracrine fashion. Full-size DOI: 10.7717/peerj.4763/ fig-3 microenvironment of SCID mice through the elevate expression of MMP2, MMP9, and VEGFR1 (Grange et al., 2011). In addition, the exosomes originated from hypoxic brain tumor glioblastoma multiform cells were increased with IL-8 and PDGF as angiogenic stimulatory molecules (Kucharzewska et al., 2013).

Role of exosomes in tumor metastasis
A major pathway in the metastatic cascade are tumor cell invasion and migration, missing the epithelial traits towards a more mesenchymal phenotype and the ability of the cell to attain a motile phenotype via changes in the cell to matrix interaction, disseminating tumor cells extravasate into remote sites and finally colonize secondary tissues and organs. There is an emerging report that shows tumor-derived exosomes are accomplished by tumor invasion and metastasis through regulating stromal cells, creating a pre-metastatic niche (Fig. 3), remodeling the extracellular matrix (ECM) and inducing angiogenesis (Alderton, 2012;Jung et al., 2009). Metastatic tumor cells dissemination enhanced level of miRNA by tumor-suppressor mechanism, that can indicate another procedure for the function of these nanovesicles in metastasis (Ostenfeld et al., 2014). The recent study illustrated that the exosomal proteins originated from tumor hypoxia of prostate cancer cells are associated with the process of adherens junctions in epithelial cells and cytoskeleton remodeling, including the enhanced metastasis and invasiveness in prostate cancer cells, is modulated through exosomes (Ramteke et al., 2015). Also, by recent investigate gastrointestinal stromal tumor cells (GISTs) secrete exosomes including protein tyrosine kinase to transform progenitor cell-derived smooth muscle cells to a premetastatic phenotype (Atay et al., 2014). Another report indicated that the Colorectal cancer cells with high invasive potential were detected to be significantly dependent on the concentration of exosomes including the signaling competent epidermal growth factor receptor (EGFR) ligand, inferring that exosome-mediated ligand shuttle causes cancer invasiveness and metastasis (Higginbotham et al., 2011). Exosome-modulated transferring of microRNA-221/222 from mesenchymal stem cells (MSCS) to gastric tumor cells significantly promotes migration and metastasis of these tumoral cells (Wang et al., 2014b).

Role of exosomes in tumor immune escape
The current researches represented that tumor-derived microvesicles may function as immunosuppressive effects. Exosome-mediated communication among cancer cells and the immune system is triggered recruiting pro-cancerogenic immune cells (Fig. 4). Also, tumor-derived exosomes are being utilized as an effective source of tumor antigen to induce dendritic cells (DCS), causing a shuttle of tumor antigens to DCs and including CD8+ T cell-related anti-tumor outcomes. The exosomal tumor-carried TGF-β1 deviated IL-2 modulates in favor of regulatory T cells and away from cytotoxic cells (Bu et al., 2011;Clayton et al., 2007). Also, tumor-derived exosomes can activate myeloid-derived suppressor cells (MDSC). The MDSCs by inhibiting the T cell reaction can apply immunosuppressive functions in cancer. tumor-derived microvesicles from several tumor cell lines modulate synthesis of interleukin-6 (IL-6) in MDSCs via the activation of Toll-like receptor 2 through the membrane-associated heat shock protein 72 (HSP 72). Making of IL-6 outcomes in an autocrine phosphorylation of stat3 in MDSCs can enhance their immunosuppressive function (Chalmin et al., 2010;Nagaraj & Gabrilovich, 2012). The miRNA shuttled via cancer cell-derived exosomes may function as ligands through attaching to the Toll-like receptors and activate the inflammation. Indeed, it was cleared that oncogenic miR-21 and miR-29a released from the exosomes derived from highly metastatic lung carcinoma cells can bind to the human and murine TLRs (Fabbri et al., 2012).

Role of exosomes in mediating Insensitivity to a drug in cancer
Exosomes via several mechanisms may play pivotal role in the progression of therapy resistance in cancer cells. Tumor-derived microvesicles can shuttle multi-drug resistance (MDR)-associated miRNAs and proteins to target cells. These illustrated that several major classes of anticancer drugs and their metabolites can be encapsulated and exported through exosomes outside of the cells, and shedding of these extracellular vesicles (EVs) is intimately associated with insensitivity to a drug ( 2012; Safaei et al., 2005;Shedden et al., 2003;Wei et al., 2014). Recently, emerging evidence illustrated that miR-21 was shuttled from cancer-associated adipocytes of fibroblasts to the various tumor cells, where it can inhibit ovarian cancer apoptosis and induce the Paclitaxel resistance through binding to its new direct target, apoptotic protease activating factor-1 (APAF1) (Yeung et al., 2016). Besides, there is plenty of interest in insensitivity to a drug through exosome-mediated shuttle of miRNAs. Several studies suggested that breast cancer cells resistant to various drugs (Docetaxel-Adriamycin-Tamoxifen) may shuttle the resistance to sensitive cells in part via exosomal miRNA exchange . Moreover, PTEN is reduced in exosomes therefore applying biological acts in target cells.
The loss of function of PTEN enhances resistance to sensitivity and chemotherapeutic of mTOR, which inhibits in breast cancer cells and, afterwards, PTEN exosomal shuttle, could be drew out as a shuttle mechanism or drug resistance changes (Steelman et al., 2008).
Besides exosomes through regulating their binding to tumor cells may counteract the efficacy of antibody drugs. The exosomes-originated lymphoma carry CD20 can bind to the anti CD-20 antibody therapeutics and induce the preserving of target cells from antibody attack (Aung et al., 2011). Thus, the exosomes-derived cancer cells can be utilized as a procedure of cancer chemotherapy resistance of special cancer cells to characteristic drugs.

Use of exosomes as a tumor diagnostics and biomarkers
The indicating of significant functional roles of exosomes in approximately all aspects of tumor cells was preparing the opportunities for enhancement of these nanovesicles as a considerable diagnostic biomarkers and remedial targets. The exosomes derived-human tumor cells are enriched with mRNAs, proteins, and miRNAs which are more plentiful in tumor than in healthy noncancerous cells (Roma-Rodrigues, Fernandes & Baptista, 2014). One of the principal beneficiaries of the utilize of these nanovesicles as a valuable biomarkers is the feasibility of a fast pathology detection by minimally invasive procedures (Li & Bahassi, 2013). The existence of exosomes in the blood circulatory system and shedding these nanovesicles into biological fluids such as urine, saliva, and ascites of exosomes containing biomarkers in several subtypes of human tumor cells can be obtained the minimally invasive ''liquid biopsies'' (for example blood collection) for clinical use (Zhang & Grizzle, 2014). Also these microvesicles are really resistant under variant storage situations containing short-term storage at 4 • C for 96 h or long-term storage at −70 • C (Taylor & Gercel-Taylor, 2008). These quality attributes of the circulating serum exosomes can be used as a considerable biomarkers for early diagnostics of cancer cells and personalized cancer therapies. Several in vitro studies suggested that exosomes derived human tumor cells can be utilized as a remarkable biomarker to diagnose cancer cells through applying the methods of proteomics and transcriptomics (Aushev et al., 2013;Dijkstra et al., 2014). Also, the enhanced levels of exosomes in blood plasma specimens of colon carcinoma patients was considerably linked to the weakly differentiated tumor cells and the declined entirely survival . Another study illustrated that exosomal EDIL3 and fibronectin in circulating EVs can utilize as pivotal biomarkers of early stage breast cancer through applying ELISA methods (Moon et al., 2016). Recent report showed that PCA3 and TMPRSS2:ERG, two established proteins exist in urinary exosomes from prostate cancer proteins which are detected as a potential biomarkers through label-free liquid chromatography-tandem mass spectrometry (LC-MS/MS) (Nilsson et al., 2009). These finding show that the bodily fluids originated exosomes may be an important noninvasive marker for the early tumor detection.

Use of exosomes as a cancer therapeutic
Emerging reports indicate that various clinical researches illustrated the role of exosomes as cancer remedies, and a few main adverse effects were identified for applying of these nanovesicles in cancer therapy. Figure 6 indicates the remedies that were proposed for therapy of cancers based on exosomes characteristics.
(1) Trough secretion of exosomes, tumoral cells trigger the alteration of the local and systemic tumor environment to induce tumor growth promotion, metastasis and insensitivity to drugs. Thus, either the destruction of exosome-dissemination pathway through tumor cells or the removal of these nanovesicles from the blood circulatory system may create an effective method for cancer therapy. The Tinzaparin (a low-molecular-weight heparin) can trigger tissue factor pathway inhibitor (TFPI) secretion from cancer cells, and also the recombinant TFPI induce suppression of tumor-derived exosomes causing migration of tumor cells (Gamperl et al., 2016). Lately for the elimination of extracellular vesicles (EVs) from the blood circulatory system, a therapeutic hemofiltration process which is called ADAPT TM (adaptive dialysis-like affinity platform technology) is applied. Whenever the patient's blood plasma samples transfer via ADAPT TM system, plasma specimens factors by the porous fibers are interacted with the immobilized affinity agents to that target molecules are particularly absorbed while unbound serum factors and blood cells can pass through this system .
(2) As a delivery system, exosomes are considerably utilized as vehicles loaded with multiple anticancer drugs, siRNAs, and miRNAs for several cancer therapeutic cargos. The lipid bilayer membrane of these nanovesicles forms a natural protective shelter, thus enhances the cellular internalization of the encapsulated anti-cancer drugs. Regarding to the exosomes originated from autologous cancer cells, these nanovesicles can cause minimal toxicity when being shuttled into the target cells and can be less immunogenic than artificial delivery vehicles. Also their naturally small size can permit them to elude phagocytosis through the mononuclear phagocyte system (MPS) and simplify their Figure 6 The main groups of exosome-based therapies. This overview includes impairing the secretion of exosomes via cancer cells and removing cancer derived exosomes, including bioactive molecules, from the blood (or other body fluids) of cancer patients; using exosomes, naturally-equipped nanocarriers, including microRNA (miRNA), small interference RNA (siRNA), and/or anticancer drugs for targeting delivery to tumor cells; the exosomes molecular composition indicates their cells of origin, may confer special cell or tissue tropism; applying exosomes as potent cell-free peptide-based vaccine demonstrate an remarkable strategy to inhibit tumor development; exosomal miRNAs can contribute to exosome-mediated cell-cell communication and induce anticancer features.
Full-size DOI: 10.7717/peerj.4763/fig-6 extravasation via tumor blood vessels and their subsequent release in target cancer tissues. The various researches illustrated that prosperous delivery and tumor inhibition utilizing this procedure. The enhancement of colorectal and breast xenograft cancers in vivo by applying the Doxorubicin loaded into exosomes or using exosome-mimetic nanovesicles can be suppressed. Thus, the efficacy of Doxorubicin was widely promoted through targeting the immature dendritic cell exosomes into cancer tissues (Jang et al., 2013;Tian et al., 2014). Also the another greatly utilized antimitotic chemotherapeutic drug is Paclitaxel that can be loaded into microvesicles through sonication, and these loaded microvesicles have 50 times more cytotoxicity than free Paclitaxel for drug resistance tumor cells in vitro. Besides the exosome-encapsulated Paclitaxel can considerably block murine Lewis lung cancer pulmonary metastases and decline size of tumor in the mouse model (Kim et al., 2016).
(3) Exosomes can be utilized to target special tissues or organs because of the having special cell tropism according to their traits. Applying the well-characterized exosomal membrane protein (Lamp2b) for expressing the targeting peptide instantly below the signal peptide sequence including the targeting peptides RVG and iRGD were prosperously inserted within these nanovesicles from immature dendritic cells to target either brain or cancer tissues. This method considerably promoted the cellular uptake of the nanovesicles in the tissue of interest, and enhanced the specificity of the remedy, and also reduced the toxicity of drugs delivered through exosomes (Jang et al., 2013;Tian et al., 2014).
(5) Also, exosomes based cell-free vaccines could indicate an alternating to dendritic cells (DCs) treatment for inhibiting tumor development through the function of exosomes in the immune system. So researchers detected that the nanovesicles originated from peptide-pulsed DCs, can present antigens to T cells to affect their immune response. These DC-originated exosomes include MHC-peptide complexes and co-stimulatory molecules on their membrane, that permit them to continue antigen presentation and increase immunization in mice comparing with antigen-presenting DCs (Luketic et al., 2007).
(6) Moreover, miRNAs are widely detected in exosomes derived cancer cells or isolated from bodily fluids that contribute to exosome-mediated cell-cell communication, and induce anti-cancer traits. For instance EGFR-specific binding peptide GE11 can lead let-7a-containing exosomes to EGFR-positive cancer cells, that considerably suppressed EGFR-positive human breast tumor cell development in a heterograft mouse model (Ohno et al., 2013;Yu et al., 2015).

FUNCTIONS AND REMEDIAL ROLES OF EXOSOMES IN DIFFERENT KINDS OF HUMAN CANCERS
The tumor exosomes originated from the ascites of a very aggressive murine T-cell lymphoma (EVs A) can effect on dendritic cells activity, thus disturbing the immune system to distinguish and destroy cancer cells. Also, the expression of marker-proteins including ALIX, TSG-101, CD63, CD81, and CD9 has detected in EVs A. This research illustrated that EVs A triggered both humoral and cellular immune reactions. Altogether, the outcomes indicated that the endosome-originated EVs secreted via an advanced-stage T-cell lymphoma, stimulated a special immune reaction (Menay et al., 2017). Besides, exosomes released through chronic myelogenous leukemia (CML) cells remedied with Curcumin, which originated from the plant Curcuma longa, has the anticancer effects, include a wide quantity of miR-21 that is transported into the endothelial cells in a biologically active form. The treatment of HUVECs with CML Curcu-exosomes diminished RhoB expression and conversely modified endothelial cells motility. The research illustrated that the addition of CML control exosomes to HUVECs induced promotion of IL8 and VCAM1 levels, but Curcu-exosomes returned this efficacy, therefore, diminished their angiogenic properties. Overall, this research showed that besides Curcumin reduces the exosome's capability to enhance the angiogenic phenotype and to modify the endothelial barrier organization (Taverna et al., 2016). As exosomes emerge as a novel manner of intercellular communication, the cargo includes through exosome is formed via somatic evolution. Regarding evaluating the effect of exosomes originated from several melanoma-related cell lines on primary CD8+ T cells act, exosomes from each of the cell lines were different. The B16F0 exosomes dose-associated inhibited T-cell proliferation. Notwithstanding, Cloudman S91 exosomes enhanced T-cell proliferation and Melan-A exosomes load an insufficient impact on primary CD8+ T cells. Importantly, B16F0 exosomes suppressed T-cell proliferation through high-expressed of PTPN11 to tumor permeating lymphocytes would escape the extracellular control of the immune checkpoints (Wu et al., 2015). Regarding increasing evidence, extracellular vesicles (EVs) are inherently trigger intercellular relation through shuttling molecular information between cells. Therefore, the autologous cancer-cell originated EVs can be utilized as helpful carries of Paclitaxel to the prostate cancer cells, bringing the drug into the cells via an endocytic process and released into the cell cytosol leading to cell death. Most considerably, the EV-mediated delivery promoted the cytotoxic efficacy of the drug. This research suggested that the autologous EVs may be helpful for impressive transporting of chemotherapeutic agents to prostate cancer cells (Saari et al., 2015). It is noteworthy that the effective role of exosomes in relevance among cancer cells and surrounding stroma indicated that the TrkB expression in exosomes is necessitated including aggressiveness phenotype. In this report, the YKL-40 silencing contributes for reducing of TrkB, sortilin and P75 NTR expression, related to a low aggressive phenotype. The release of TrkB in exosomes from normal glioma cells was able to relieve both migration and activation of YKL-40-inactivated cells. Furthermore, TrkB-containing exosomes may be remarked as a considerable biomarker for glioblastoma diagnosis (Pinet et al., 2016). Also, MVs originated from HLSC (MV-HLSC) can suppress the growth of hepatoma tumors through shuttling genetic information that mediates with deregulated survival and proliferation of these cells. The antitumor effect of MV-HLSC was relevant to the decreased internalization, due to the lack of CD29 on MV-fibroblast or a decreased expression of antitumor miRNAs including miR-24, miR-31, miR-122, miR-125b, miR-223, and miR-451. Consequently, the promoted internalization was not relevant to an increased biological activity when MV-fibroblast expressing CD-29 were utilized. Hence, the various composition of miRNA content between MV-HLSC and MV-fibroblast was the remarkable reason for the various biological actions. Therefore, the transferring of these miRNAs through MVs originated from stem cells may suppress tumor growth development and stimulate apoptosis (Fonsato et al., 2012). Another research illustrated that exosomes originated from curcumin-pretreated H1299 cells were utilized to remedy BEAS-2B cells, which triggered proliferation, colony organization, and migration of BEAS-2B cells. Curcumin is a new drug lung cancer remedy. Although, the procedure associated with the antitumor effect of curcumin is related to the promoted expression of TCF-21, triggered through a low expression of DNMT1. Therefore, mechanism of curcumin is remarkable in cancer remedy, and creates the pivotal biomarkers for developing cancer diagnostic and remedial procedures (Wu et al., 2016). The new research suggested that PSC (Pancreatic Stellate Cells) originated exosomes can trigger and elevate the proliferation and migration of PANC-1 and SUIT-2. The exosomes differentially varied expression of a plethora of genes controlling multiple cellular procedures containing cell cycle, cellular assembly and organization, DNA replication, recombinant and repair, cell death and survival, cellular development, and growth in the recipient cancer cells. Also, three chemokines, CCL20, CXCL1, and CXCL2 were detected high expressed in exosome-treated cancer cells. Besides, GPC1 (glypican-1), a glycoprotein discovered in PSC exosomes, as a pivotal biomarker to distinguish PDAC (Pancreatic Ductal Adenocarcinoma), and as a tumor promoter shuttled among cells through exosomes (Ali et al., 2015;Charrier et al., 2014;Farrow et al., 2003). The exosome/staphylococcal enterotoxin B is a considerable sample for apopto-immunotherapy. The contribution of Exo and its lipid rafts in this structure assigns the feasibility of binding to pancreatic cancer cells. SEB and the characterized lipid rafts trigger the apoptotic signal both through extrinsic and mitochondria-dependent pathways. Also, the presence of tumor antigens associated with superantigen causing promotion of specific antitumor immune response (Mahmoodzadeh et al., 2014). Even more recent research detected that gastric cancer cells may release exosomes for transferring apoptotic signals without direct cell-cell contact to anti-cancer T cells. The Cbl-b and Cbl-c of ubiquitin ligases might have a considerable role in exosome-induced apoptosis of Jurkat T cells through enhancing PI3K proteasome degradation, that can cause inactivation of PI3K/Akt signaling, therefore led to activation of caspase 3, 8, and 9. Thus, relation among exosomes and immune response is presumably to assign considerable point of view through the process of tumor immune inhibition (Qu et al., 2009). Recently study illustrated that miR-375 promoted the growth inhibitory effect, Cell progression and dissemination of colon cancer through the Bcl-2 pathway. Therefore the miR-375 down-regulated in metastatic CRC, and it has important role for Bcl-2 blocking, with the significant minimally invasive prognostic biomarker for CRC through suppression of malignant proliferation and dissemination (Zaharie et al., 2015). Further, research reported that a HIV-Nef SMR-originated peptide suppressed the progress of human breast tumor cells through arresting cancer cell cycle and including blockade of exosome secretion. The SMR peptide inhibited the cancer cell cycle through G2/M phase boundary. While the SMR peptide and chemotherapeutic drugs were compound to remedy cancer cells, PEG-SMRwt-Clu synergically enhanced the anti-proliferative efficacies of drugs, considerably promoted the tumor cell growth suppression efficacy of drugs and inhibited exosomes secretion in breast cancer cell lines MCF-7 and MDA-MB-231 cells. Therefore the considerable usage of PEG-SMRwt-Clu peptide is pivotal process for the prevention and therapy of human breast tumor cells (Huang et al., 2017).

CONCLUSIONS
Prosperity in remedy against intricate cancers relies on our full comprehension of the complications among various components within tumors. The above studies supported the viewpoint that exosomes can play a pivotal role in the growth, and promotion of cancer cells via regulation of intercellular communication into the tumor microenvironment through the release of several biological molecules ranging from virions of mRNA, miRNA,  Monad-mediated degradation is one of the mechanisms that determines the stability of amphiregulin mRNA and that Monad-amphiregulin axis plays an essential role in the invasion of breast cancer cells.          The cargo of HuT-102-derived exosomes included of miR-21, miR-155 and vascular endothelial growth factor. Also, HuT-102derived exosomes not only deliver Tax to recipient MSCs, but also induce NF-κB activation leading to an alteration in cellular morphology, promote in proliferation and the induction of gene expression of migration and angiogenic markers.

El-Saghir et al. (2016)
TGFβ1, latency-associated protein (LAP), CD9, CD81, CD34, and CD 117 The blood plasma of acute myeloid leukemia (AML) patients at diagnosis, post-induction CT, during consolidation CT, in long-term remission, and from healthy volunteers Flow cytometry assay, Enzymelinked immunosorbent assay (ELISA), and Western blotting The changes in total exosomal protein levels and the presence of various forms of transforming growth factor-beta1 (TGF-b1) carried by AML exosomes reflect effects of remedy and might serve as indicators of leukemic relapse in AML patients. Besides, AML exosomes carrying an active form of TGF-b1 induced down-regulation of NKG2D expression in normal natural killer (NK) cells.

Exosomal cargos Cancer cell types Methods Clinical values References
MiR-96-5p, MiR-182-5p, and MiR-149 The human colon carcinoma cell lines HT-29 and HCT-116 cells The peripheral fasting blood specimens of colon carcinoma patients The human colon carcinoma tissues and normal tissue samples qRT-PCR analysis, Flow cytometry assay, and Western blotting The considerably promoted GPC1 + exosomes are present in the plasma of CRC patients and can be released from CRC tumor cells. The high expression of miR-96-5p and miR-149 significantly decreased cell viability and enhanced cell apoptosis in HT-29 and HCT-116 cells, and suppressed the growth of xenograft HT-29 and HCT-116 tumors.

Li et al. (2017)
Dickkopf-related protein 4 (DKK4) The human colon carcinoma cell lines SW480 and SW480APC qRT-PCR analysis, Electron microscopy assay, and Western blotting The secretion of Wnt antagonist, dickkopf-related protein 4 (DKK4) enhanced in SW480APC colon carcinoma cells derived exosomes. In addition, the promoter region of the DKK4 gene appears to have decreased methylation in SW480APC cells, comparing with the paternal SW480 cells, as well as reduced expression of DNA methyltransferase 3a (DNMT-3a).

Lim et al. (2012)
Tumor suppressor-activated pathway 6 (TSAP6) The human colon carcinoma cell line HCT-116 TP53wild type, and HCT-116 TP53-null cells The human colon carcinoma tissues and normal tissue samples The peripheral fasting blood specimens of colon carcinoma patients qRT-PCR analysis, Flow cytometry assay, and Western blotting The expression of TSAP6 is not related with release of exosomes; and regulation of TSAP6 through P53 was not detected either in tumor samples or in HCT-116cell lines. Besides, it was not shown that the P53/TSAP6 pathway regulates the release of exosomes into the plasma of colorectal cancer patients.  The stomach adenocarcinoma cell line SGC-7901 cells qRT-PCR analysis, Electron microscopy assay, and Western blotting CD97 elevates gastric cancer cell proliferation and invasion in vitro via exosome-mediated MAPK signaling pathway, and also exosomal miRNAs including miR-2861 and miR-4734 are probably involved in activation of the CD97-associated pathway.

Arita et al. (2016)
Epidermal growth factor receptor (EGFR) The human GC liver metastatic and paired adjacent non-cancerous tissues Male nude mice (BALB/cnu, 6 to 8 weeks) The human gastric adenocarcinoma cell line SGC7901 cells The primary mouse liver cells were obtained from the livers of C57BL/6J mice (6-8 weeks of age) qRT-PCR analysis, Enzyme-linked immunosorbent assay (ELISA), Electron microscopy assay, Nanoparticle tracking analysis (NTA), and Western blotting The EGFR-containing exosomes derived from cancer cells is demonstrated to impressively activate hepatocyte growth factor (HGF) by inhibiting miR-26a/b expression. In addition, the high expressed of paracrine HGF, which binds the c-MET receptor on the migrated cancer cells, provides fertile 'soil' for the 'seed', simplifying the landing and proliferation of metastatic cancer cells.

HLA-A, and CD9
The human gastric adenocarcinoma cell line SGC7901 and Jurkat T cells qRT-PCR analysis, Electron microscopy assay, Western blotting and Immunoprecipitation The Cbl family of ubiquitin ligases might be involved in regulation of exosome-induced apoptosis of Jurkat T cells by promoting PI3K proteasome degradation, inactivation of PI3K/Akt signaling, and mediating some effects of caspase activation.

Sagar et al. (2015)
HSP70 The MIA Paca-2, an epithelial-like pancreatic cancer cell line Electron microscopy assay, Western blotting The EXO/SEB is a novel model or apopto-immunotherapy, being able to induce apoptosis in addition to specific immune responses. The enhanced expression of antiapoptotic genes including Bax, Bak and fas in cells treated with the EXO/SEB causes promotion of apoptosis. In addition, EXOs released from pancreatic cancer cells can trigger the mitochondrial-dependent apoptosis and increase the caspase-3 and caspase-9 activities.  MiR-1246, miR-4644, miR-3976, and miR-4306 were significantly upregulated in 83% of PaCa serum-exosomes, but rarely in control groups. These miRNA were also elevated in exosomedepleted serum of patients with PaCa, but at a low level. Also, the expression of the PaCIC markers CD24, CD44v6, CD104, Tspan8, EpCAM, MET, and CD151 and the common exosome markers CD9 and CD63 was based on high expression in tumor tissue.

Exosomal cargos Cancer cell types Methods Clinical values References
MiR-378a,  30 blood plasma samples (10 patients affected by lung adenocarcinomas, 10 with lung granulomas, and 10 healthy smokers) qRT-PCR analysis The production of exosomes containing miRNAs in the lung carcinoma cells are completely different to those present in healthy control cells from which neoplastic cells originated.

Cazzoli et al. (2013)
MiR  Plasma samples from patients with lung adenocarcinoma and a control group without known lung cancer or other active cancer

Microarray analysis
The considerable difference in total exosome and miRNA levels between lung cancer patients and controls, and the similarity between the circulating exosomal miRNA and the tumor-derived miRNA patterns, suggest that circulating exosomal miRNA might be useful as a screening test for lung adenocarcinoma.

qRT-PCR analysis, and Western blotting
The anti-cancer effects of Curcumin are associated with upregulation of transcription factor 21 (TCF21), mediated by downregulation of DNMT1. Also, TCF21 overexpression and knockdown was introduced to H1299 cells through lentiviral system, which led to suppression and promotion of lung tumor growth, respectively.

Wu et al. (2016)
CD63, flotillin-1, and HSP70 The human lung adenocarcinoma cell lines A549, and H460 cells BALB/c nude male mice qRT-PCR analysis, Flow cytometry assay, Electron microscopy assay, and Western blotting The β-elemene significantly suppressed growth and induced apoptosis in lung cancer cells. The levels of the anti-apoptotic genes Bcl-2 and Bcl-xl in A549 cells decreased, while expression of P53 and production of exosomes, and the exosome markers CD63, flotillin-1, and HSP70 increased after β-elemene remedy.
Li, Liu & Wang (2014) (continued on next page)   The Cy3-labeled miR-21 mimics could be transferred between esophageal cancer cells by exosomes. Thus, the miR-21 mimics could affect migration and invasion of recipient cells partly via modulation of its target gene PDCD4 and its downstreamsignaling molecules, MMP-2 and MMP-9 by using the cell co-culture system. Also, miR-21 was upregulated significantly in plasma from esophageal cancer patients and indicated a significant risk association for esophageal cancer.

Enzyme-linked immunosorbent assay (ELISA), and Western blotting
The heat shock protein HSP27 has been correlated in OVCAR-3 and SK-OV-3 cells ovarian cancer cell lines by exosomes with aggressiveness and chemoresistance and, thus, represents a promising potential biomarker for OC diagnosis, prognosis, and treatment response.

Stope et al. (2017)
CA-125, EpCAM, and CD24 The blood plasma samples of ovarian cancer (OC) patients Flow cytometry assay, Enzymelinked immunosorbent assay (ELISA), Electron microscopy assay, and Western blotting Through the exosome analysis enabled by the ExoSearch chip has been applied for ovarian cancer diagnosis via quantifying a panel of tumor markers from exosomes in a small-volume of blood plasma (20 µL), which indicated significant diagnostic accuracy and was comparable with standard Bradford assay.

Zhao et al. (2016)
MiR-584,  The human Hepatocellular carcinoma (HCC) cell lines Hep3B, HepG2, and PLC/PRF/5 cells qRT-PCR analysis, , Flow cytometry assay, and Electron microscopy assay The HCC cell-derived exosomes can modulate β activated kinase-1 (TAK1) expression and associated signaling and promote transformed cell growth in recipient cells. Loss of TAK1 has been implicated in hepatocarcinogenesis and is a biologically plausible target for intercellular modulation.       qRT-PCR analysis, Flow cytometry assay, and Western blotting The promotion of miR-9 elevates temozolomide (TMZ)-resistant GBM cells. To block miR-9, methods were developed with Cy5-tagged anti-miR-9. Dye-transfer studies indicated intracellular communication between GBM cells and MSCs. This occurred by gap junctional intercellular communication and the release of microvesicles. Thus, anti-miR-9 was transferred from MSCs to GBM cells.

Munoz et al. (2013)
CRYAB (crystallin, alpha B), CD9, CD63 The human glioma cell line U373 cells Enzyme-linked immunosorbent assay (ELISA), Electron microscopy assay, and Western blotting Increase in CRYAB levels in GBM coupled with its secretion via exosomes points to an important mode of intercellular communication which, in GBM, may confer resistance to apoptosis in surrounding cells following radiation and chemo-therapies.
Proinflammatory cytokines also bring about profound changes in the proteome of the exosome.

Kore & Abraham (2014)
CD11b, CD14, CD16, and CD163 The glioblastoma multiforme (GBM) tissue samples The human peripheral blood mononuclear cells (PBMC) of GBM patients Enzyme-linked immunosorbent assay (ELISA), Flow cytometry assay, and Luminex Analysis The M2-like monocytes expressing CD14+ and CD163+, another indicator of Th2 bias, are promoted in GBM patient blood and associated with high serum concentrations of colony 2 stimulating factor 2 and 3, as well as interleukin-2, -4, and -13, the latter 2 cytokines being hallmarks of Th2 immunity. Fractionation of GBM patient sera into samples enriched for exosomes or soluble factors proved that both fractions are capable of inducing CD163 expression in normal monocytes.

Nanofilament
The human glioblastoma cell lines U87 and U251cells The human melanoma cell line SKMEL cells Normal human astrocytes (NHA) Piezoresponse force microscopy (PFM) Compared with normal exosomes, glioblastoma exosomes displayed numerous nanofilaments, and the nanofilaments were trypsinand RNase-resistant. Based on in vitro uptake assays, glioblastoma exosomes indicated a significantly higher uptake in cells compared with normal exosomes.  The included AS-ODN releasing from the chambers is directed against the insulin-like growth factor type-1 receptor, is immunostimulatory, and therefore leading to promote presentation of these antigens. The glioma-derived exosomes were detected to express CD63, CD71, and CD81, endosomal antigens.

Harshyne et al. (2015a)
CD 9, CD63, and CD81 The brain neuronal glioblastoma-astrocytoma cell line U-87 MG cells The Immortalized mouse brain endothelial cell line bEND.3 cells The neuroectodermal tumor cell line PFSK-1 cells The glioblastoma cell line A-172 cells qRT-PCR analysis, Flow cytometry assay, Electron microscopy assay, Enzyme-linked immunosorbent assay (ELISA), and Western blotting The exosomes released from brain endothelial cells delivered anticancer drug across the blood-brain barrier (BBB), which subsequently exerted cytotoxic efficacy against brain cancer. Also, the high presence of CD63 in bEND.3 exosomes indicates that these exosome nanovesicles might be differently implicated in receptor-mediated transport across the BBB.

Exosomal cargos Cancer cell types Methods Clinical values References
Collagen type VI alpha 1, putative RNA-binding protein 15B chain A, substrate induced remodeling of the active site regulates HTRA1, coatomer protein complexsubunit beta 2, myosin-heavy chain 1, keratin-type I cytoskeletal 9, HSP90, and CD63 The brain neuronal glioblastomaastrocytoma cell line U-87 MG cells Electron microscopy assay, matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS) analysis, and Western blotting Through the proteome analysis of U-87MG exosome the Hsp90 was promoted in exosomes exposed to a low temperature compared with exosomes incubated under normal conditions. Also, there was detected an increase expression of calcium-dependent secretion activator 2 isoform b, hCG1817425, armadillo repeat-containing protein 4, and immunoglobulin heavy variable 5-a in low temperatureexposed proteome. Besides, the proteins that were reduced on the L.T. gel were collagen alpha-1(VI), DNA topoisomerase I, titin, mitochondrial isoform 2, RNA-binding protein 15B, phosphoserine aminotransferase isoform 2, and Chain A, Substrate Induced Remodeling Of The Active Site Regulates HTRA1 Activity.
qRT-PCR analysis, Flow cytometry assay, and Luciferase reporter assay The result indicated a new exosomic miR-21/TLR8/NF-κB/exosomic miR-155/TERF1 axis triggered regardless of M1or M2-polarization, but not in dendritic cells involved in resistance to chemotherapy in NBL, and identifies exosomes within the TME as important molecular targets to restore drug sensitivity.
The human melanoma cell line A375 cells.
Electron microscopy assay, and Western blotting The SH-SY5Y neuroblastomaderived exosomes comprised of MHC II, Hsp90 and flotillin-1, whereas other cargo proteins or neuron specific proteins, such as actin or tau, NeuN, Sv2, are not released. Moreover, the results showed that, when applied extracellularly, exosomes released from neuronal cells modulated differentiation of melanoma cells. (2015) protein, lipid, and DNA cargos. An overview of the roles of exosomes in different types of cancer and the molecular mechanisms that have been used to evaluate the effect of EV in cancer progression and metastasis were presented in Table 1. The exploration of exosomes derived cancer cells contents may permit the progression of new diagnostic and remedial procedures, with minimally invasive approaches. Exosomes derived cancer cells also can cause cancer cell development and metastasis through suppressing the immune response and via enhancing chemoresistance by elimination of chemotherapeutic anti-cancer drugs. So they might be significant targets for remedial interventions through their alternation or elimination. The field of nanotechnology has widely benefitted exosome research to load nanovesicles with tiny molecules or drugs for cancer treatment because of their small size, lack of toxicity and target specificity toward prosperous immunotherapy in clinical trials. Besides exosomes can be considerable biomarkers for diagnosis of cancer and targeted remedy due to their nearly display the situation of their parental cells that are relatively constant in the blood circulation and could be feasibility obtained from body fluids. Most significantly the role of miRNA in the context of exosomes for targeting inactivation of cancer-causing miRNAs would probably provide a novel strategy for most cancers. It is expected that further research on these microvesicles will not only determine great potential and hopeful effect on their functions in the pathogenesis of cancer but also will open the new strategies for cancer diagnosis and remedies.