Microvesicles secreted by macrophages shuttle invasion-potentiating microRNAs into breast cancer cells

Exosome and Secretion: Action On?

Originally treated as part of a cellular waste, extracellular vesicles (EVs) are being shown to possess a vast variety of functions, of which exosome is the most studied one. Most cells, such as tumor cells, immunocytes, and fibroblasts can secrete exosomes, especially under certain stresses the amount is much higher, and the contents of exosome represent the status of the donor cells and the tumor microenvironment. As crucial transporters for cells' content exchange, much attention has been raised in the utilities of exosomes to suppress immune response, and to modify a microenvironment favorable for cancer progression. Exosomal immune checkpoints, such as programmed cell death ligand 1 (PD-L1), contribute to immunosuppression and are associated with anti-PD-1 response. Many forms of soluble immune checkpoint receptors have also been shown to influence efficacy mediated by their therapeutic antibodies. Therefore, targeting pro-tumorous exosomes may achieve antitumor effect supplementary to existing therapies. Exosome, itself natural liposome-like structure, allows it to be a potential drug delivery tool.

MicroRNAs and Metastasis

Metastasis, the development of secondary malignant growths at a distance from the primary site of a cancer, is associated with almost 90% of all cancer deaths, and half of all cancer patients present with some form of metastasis at the time of diagnosis. Consequently, there is a clear clinical need for a better understanding of metastasis. The role of miRNAs in the metastatic process is beginning to be explored. However, much is still to be understood. In this review, we present the accumulating evidence for the importance of miRNAs in metastasis as key regulators of this hallmark of cancer.

Exosomes in Cancer: Circulating Immune-Related Biomarkers

Exosomes, the smallest vesicles (30–100 nm) among multivesicular bodies, are released by all body cells including tumor cells. The cargo they transfer plays an important role in intercellular communication. Tumor-derived exosomes (TEXs) maintain interactions between cancer cells and the microenvironment. Emerging evidence suggests that tumor cells release a large number of exosomes, which may not only influence proximal tumor cells and stromal cells in the local microenvironment but can also exert systemic effects as they are circulating in the blood. TEXs have been shown to boost tumor growth promote progression and metastatic spread via suppression or modification of the immune response towards cancer cells, regulation of tumor neo-angiogenesis, pre-metastatic niche formation, and therapy resistance. In addition, recent studies in patients with cancer suggest that TEXs could serve as tumor biomarker reflecting partially the genetic and molecular content of the parent cancer cell (i.e., as a so-called “liquid biopsy”). Furthermore, recent studies have demonstrated that exosomes may have immunotherapeutic applications, or can act as a drug delivery system for targeted therapies with drugs and biomolecules.

Cancer-Derived Extracellular Vesicle-Associated MicroRNAs in Intercellular Communication: One Cell's Trash Is Another Cell's Treasure

Several non-protein-coding genomic regions, previously marked as "junk DNA", have been reported to be transcriptionally active, giving rise to non-coding RNA species implicated in fundamental biological and pathological processes. In particular, microRNAs (miRNAs), a class of small non-coding RNAs mediating post-transcriptional gene silencing, are causally involved in several human diseases, including various cancer types. Extracellular vesicles (EVs) are membranous structures physiologically released by most cell types. Initially, they were considered a "waste-removal" mechanism, through which cells could dispose unnecessary material and organelles. It is now widely demonstrated that EVs also play a critical role in intercellular communication, mediating the horizontal transfer of lipids, proteins, and genetic material. A paradigm shift in the biology of miRNAs was represented by the discovery that EVs, especially from cancer cells, contain miRs. EV-associated miRs act as autocrine, paracrine and endocrine factors, participating in cancer pathogenesis by modulating intercellular communication. Noteworthy, these formerly neglected molecules are now considered the next generation of cancer "theranostic" tools, with strong clinical relevance. In this review, we aim to summarize the most recent findings regarding EV-associated miRs in cancer pathogenesis and in the development of novel anti-neoplastic diagnostic and therapeutic approaches.

MicroRNA-A Tumor Trojan Horse for Tumor-Associated Macrophages

MicroRNAs (miRs) significantly contribute to the regulation of gene expression, by virtue of their ability to interact with a broad, yet specific set of target genes. MiRs are produced and released by almost every cell type and play an important role in horizontal gene regulation in the tumor microenvironment (TME). In the TME, both tumor and stroma cells cross-communicate via diverse factors including miRs, which are taking central stage as a therapeutic target of anti-tumor therapy. One of the immune escape strategies adopted by tumor cells is to release miRs as a Trojan horse to hijack circulating or tumor-localized monocytes/macrophages to tune them for pro-tumoral functions. On the other hand, macrophage-derived miRs exert anti-tumor functions. The transfer of miRs from host to recipient cells depends on the supramolecular structure and composition of miR carriers, which determine the distinct uptake mechanism by recipient cells. In this review, we provide a recent update on the miR-mediated crosstalk between tumor cells and macrophages and their mode of uptake in the TME.

Extracellular Vesicles in Modifying the Effects of Ionizing Radiation

Extracellular vesicles (EVs) are membrane-coated nanovesicles actively secreted by almost all cell types. EVs can travel long distances within the body, being finally taken up by the target cells, transferring information from one cell to another, thus influencing their behavior. The cargo of EVs comprises of nucleic acids, lipids, and proteins derived from the cell of origin, thereby it is cell-type specific; moreover, it differs between diseased and normal cells. Several studies have shown that EVs have a role in tumor formation and prognosis. It was also demonstrated that ionizing radiation can alter the cargo of EVs. EVs, in turn can modulate radiation responses and they play a role in radiation-induced bystander effects. Due to their biocompatibility and selective targeting, EVs are suitable nanocarrier candidates of drugs in various diseases, including cancer. Furthermore, the cargo of EVs can be engineered, and in this way they can be designed to carry certain genes or even drugs, similar to synthetic nanoparticles. In this review, we describe the biological characteristics of EVs, focusing on the recent efforts to use EVs as nanocarriers in oncology, the effects of EVs in radiation therapy, highlighting the possibilities to use EVs as nanocarriers to modulate radiation effects in clinical applications.

MicroRNAs Contribute to Breast Cancer Invasiveness

Cancer statistics in 2018 highlight an 8.6 million incidence in female cancers, and 4.2 million cancer deaths globally. Moreover, breast cancer is the most frequent malignancy in females and twenty percent of these develop metastasis. This provides only a small chance for successful therapy, and identification of new molecular markers for the diagnosis and prognostic prediction of metastatic disease and development of innovative therapeutic molecules are therefore urgently required. Differentially expressed microRNAs (miRNAs) in cancers cause multiple changes in the expression of the tumorigenesis-promoting genes which have mostly been investigated in breast cancers. Herein, we summarize recent data on breast cancer-specific miRNA expression profiles and their participation in regulating invasive processes, in association with changes in cytoskeletal structure, cell-cell adhesion junctions, cancer cell-extracellular matrix interactions, tumor microenvironments, epithelial-to-mesenchymal transitions and cancer cell stem abilities. We then focused on the epigenetic regulation of individual miRNAs and their modified interactions with other regulatory genes, and reviewed the function of miRNA isoforms and exosome-mediated miRNA transfer in cancer invasiveness. Although research into miRNA’s function in cancer is still ongoing, results herein contribute to improved metastatic cancer management.

Exosomes: Versatile Nano Mediators of Immune Regulation

One of many types of extracellular vesicles (EVs), exosomes are nanovesicle structures that are released by almost all living cells that can perform a wide range of critical biological functions. Exosomes play important roles in both normal and pathological conditions by regulating cell-cell communication in cancer, angiogenesis, cellular differentiation, osteogenesis, and inflammation. Exosomes are stable in vivo and they can regulate biological processes by transferring lipids, proteins, nucleic acids, and even entire signaling pathways through the circulation to cells at distal sites. Recent advances in the identification, production, and purification of exosomes have created opportunities to exploit these structures as novel drug delivery systems, modulators of cell signaling, mediators of antigen presentation, as well as biological targeting agents and diagnostic tools in cancer therapy. This review will examine the functions of immunocyte-derived exosomes and their roles in the immune response under physiological and pathological conditions. The use of immunocyte exosomes in immunotherapy and vaccine development is discussed.

Exosomal miR-196a-1 promotes gastric cancer cell invasion and metastasis by targeting SFRP1

Aim: To investigate the role of exosomal miRNAs on gastric cancer (GC) metastasis. Materials & methods: miRNA expression profiles of exosomes with distinct invasion potentials were analyzed using miRNA microarray and validated by quantitative real-time PCR. In vitro and in vivo experiments assessed the role of exosomal miR-196a-1 in GC's metastasis. Results: High expression level of exosomal miR-196a-1 expression was significantly associated with poor survival in GC. Exosomes that contained miR-196a-1 were secreted from high-invasive GC cells. Ectopic miR-196a-1 expression promoted invasion of low-invasive GC cells by targeting SFRP1. Conclusion: miR-196a-1 was delivered from high-invasive GC into low-invasive GC cells via exosomes and promoted metastasis to the liver in vitro and in vivo.

Exosomes from Adipose-Derived Stem Cells (ADSCs) Overexpressing miR-21 Promote Vascularization of Endothelial Cells

In the past few years, exosomes released from adipose-derived stem cells (abbreviated as ADSCs) have shown promises to provide therapeutic benefits in the fields of regenerative medicine. miRNAs, existing in exosomes, are endogenous, small noncoding RNAs that play important roles in a variety of cellular functions and tumor development. Emerging evidences have indicated that miR-21 is one of the important miRNAs associated with tumor angiogenesis. In this study, we identified the role of exosomes from ADSCs overexpressing miR-21 in regulating/promoting vascularization of endothelial cells. Experimental data indicated an elevated miR-21 level in exosomes released by ADSCs overexpressing miR-21. In vitro matrigel angiogenesis assay showed that exosomes secreted by ADSCs overexpressing miR-21 significantly promoted the vascularization of HUVEC cells (an endothelial cell line). Quantitative real-time polymerase chain reaction (qRT-PCR) and western blot (WB) revealed an upregulation of HIF-1α, VEGF, SDF-1, p-Akt, p-ERK1/2 and downregulation of PTEN in response to miR-21 overexpression, indicating that miR-21 enriched exosomes induced angiogenesis through Akt and ERK activation and also HIF-1α and SDF-1 expression. Our work suggests that exosomes from ADSCs that overexpressing miR-21 can potentially promote vascularization and therefore the transplantation of exosomes from their culture may be suitable for clinical effort in regenerative medicine.

Cancer-Derived Exosomes as Effectors of Key Inflammation-Related Players

Exosomes, a category of small lipid bilayer extracellular vesicles that are naturally secreted by many cells (both healthy and diseased), carry cargo made up of proteins, lipids, DNAs, and RNAs; all of which are functional when transferred to their recipient cells. Numerous studies have demonstrated the powerful role that exosomes play in the mediation of cell-to-cell communication to induce a pro-tumoral environment to encourage tumor progression and survival. Recently, considerable interest has developed in regard to the role that exosomes play in immunity; with studies demonstrating the ability of exosomes to either metabolically alter immune players such as dendritic cells, T cells, macrophages, and natural killer cells. In this review, we summarize the recent literature on the function of exosomes in regulating a key process that has long been associated with the progression of cancer-inflammation and immunity.

Intercellular Crosstalk Via Extracellular Vesicles in Tumor Milieu as Emerging Therapies for Cancer Progression

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Increasing evidence has suggested that extracellular vesicles (EV) mediated bidirectional transfer of functional molecules (such as proteins, different types of RNA, and lipids) between cancer cells and tumor stromal cells (immune cells, endothelial cells, fibroblasts, stem cells) and strongly contributed to the reinforcement of cancer progression. Thus, intercellular EV-mediated signaling in tumor microenvironment (TME) is essential in the modulation of all processes that support and promote tumor development like immune suppression, angiogenesis, invasion and metastasis, and resistance of tumor cells to anticancer treatments.

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Besides EV potential to revolutionize our understanding of the cancer cell-stromal cells crosstalk in TME, their ability to selectively transfer different cargos to recipient cells has created excitement in the field of tumortargeted delivery of specific molecules for anticancer treatments. Therefore, in tight connection with previous findings, this review brought insight into the dual role of EV in modulation of TME. Thus, on one side EV create a favorable phenotype of tumor stromal cells for tumor progression; however, as a future new class of anticancer drug delivery systems EV could re-educate the TME to overcome main supportive processes for malignancy progression.

Emerging role of exosomes as promising diagnostic tool for cancer

The incidence of cancer is experiencing a steep rise in recent times. A survey report produced by GLOBOCAN 2018 estimates about 18.1 million new cases of cancer across 20 regions of the world. The bewildering number of people afflicted with cancer demands rapid diagnosis and treatment strategy. The current methods used for diagnosis of cancer are expensive, invasive, and time consuming. Hence, a new diagnostic panel has to be laid down to make the process less invasive, cost-effective, and rapid. A venture into identifying potential diagnostic targets introduced exosomes to the scientific community. A plethora of roles being packed into these biological cargoes makes them attractive targets for both therapeutic and diagnostic applications. Exosomes are membrane-bound extracellular vesicles packed with DNA, RNA, and proteins. Their presence in a wide array of body fluids such as breast milk, blood plasma, saliva, urine, serum, and cerebrospinal fluid makes them an excellent source of potential biomarkers. These nano-scale structures are capable of crossing hypoxic regions, systemic circulation and the territories of blood vessel barriers. In line with the above facts, the present review focuses on the therapeutic and diagnostic applications of exosomes in cancer.

MicroRNAs as Therapeutic Targets in Nasopharyngeal Carcinoma

Nasopharyngeal carcinoma (NPC) is a malignancy of epithelial origin that is prone to local invasion and early distant metastasis. Although concurrent chemotherapy and radiotherapy improves the 5-year survival outcomes, persistent or recurrent disease still occurs. Therefore, novel therapeutic targets are needed for NPC patients. MicroRNAs (miRNAs) play important roles in normal cell homeostasis, and dysregulations of miRNA expression have been implicated in human cancers. In NPC, studies have revealed that miRNAs are dysregulated and involved in tumorigenesis, metastasis, invasion, resistance to chemo- and radiotherapy, and other disease- and treatment-related processes. The advantage of miRNA-based treatment approaches is that miRNAs can concurrently target multiple effectors of pathways involved in tumor cell differentiation and proliferation. Thus, miRNA-based cancer treatments, alone or combined with standard chemotherapy and/or radiotherapy, hold promise to improve treatment response and cure rates. In this review, we will summarize the dysregulation of miRNAs in NPC initiation, progression, and treatment as well as NPC-related signaling pathways, and we will discuss the potential applications of miRNAs as biomarkers and therapeutic targets in NPC patients. We conclude that miRNAs might be potential promising therapeutic targets in nasopharyngeal carcinoma.

The Role of Exosomal MicroRNAs in the Tumor Microenvironment of Breast Cancer

Breast cancer, ranking first among women's cancers worldwide, develops from the breast tissue. Study of the breast tissue is, therefore of great significance to the diagnosis and treatment of breast cancer. Exosomes, acting as an effective communicator between cells, are in the ascendant in recent years. One of the most important cargoes contained in the exosomes is microRNAs, belonging to the non-coding RNA family. When the exosomal microRNAs are absorbed into the intracellular location, most of the microRNAs will act as tumor promoters or suppressors by inhibiting the translation process of the target mRNA, thus affecting the behavior of other stromal cells in the tumor microenvironment. At present, growing research focuses on the different types of donor cell sources, their contribution to cancer, miRNA profiling, their biomarker potential, etc. This review aims to state the function of diverse miRNAs in exosomes medicated cell-cell communication and the potency of some specific enriched miRNAs as molecular markers in clinical trials. We also describe the mechanism of anti-cancer compounds through exosomes and the exploration of artificially engineered techniques that lead miRNA-inhibitors into exosomes for therapeutic use.

Effect of immunosuppression in miRNAs from extracellular vesicles of colorectal cancer and their influence on the pre-metastatic niche

Colorectal cancer (CRC) occurs with more aggressiveness in kidney transplant recipients compared to the general population. Immunosuppressive therapy plays a crucial role in the development of post-transplant malignancy. Concretely, cyclosporine A (CsA) has intrinsic pro-oncologic properties, while several studies report a regression of cancer after the introduction of rapamycin (RAPA). However, their effect on the extracellular vesicle (EV) content from CRC cell lines and their relevance in the pre-metastatic niche have not yet been studied. Here, we investigated the effect of RAPA and CsA in EV-miRNAs from metastatic and non-metastatic CRC cell lines and the role of relevant miRNAs transferred into a pre-metastatic niche model. EV-miRNA profiles showed a significant upregulation of miR-6127, miR-6746-5p, and miR-6787-5p under RAPA treatment compared to CsA and untreated conditions in metastatic cell lines that were not observed in non-metastatic cells. From gene expression analysis of transfected lung fibroblasts, we identified 22 shared downregulated genes mostly represented by the histone family involved in chromatin organization, DNA packaging, and cell cycle. These results suggest that EV-miR-6127, miR-6746-5p and miR-6787-5p could be a potential epigenetic mechanism induced by RAPA therapy in the regulation of the pre-metastatic niche of post-transplant colorectal cancer.

Circulating MicroRNAs in Cancer: Potential and Challenge

MicroRNAs (miRNAs) are endogenous non-coding small RNA molecules that can be secreted into the circulation and exist in remarkably stable forms. Like intercellular miRNAs, circulating miRNAs participate in numerous regulations of biological process and expressed aberrantly under abnormal or pathological status. The quality and quantity changes of circulating miRNAs are associated with the initiation and progression of cancer and can be easily detected by basic molecular biology techniques. Consequently, considerable effort has been devoted to identify suitable extracellular miRNAs for noninvasive biomarkers in cancer. However, several challenges need to be overcome before the practical application. In this review, we discuss several issues of circulating miRNAs: biological function and basic transport carriers; extracellular cell communication process; roles as reliable cancer biomarkers and usage in targeted cancer therapy; and challenges for clinical application.

New insight into isolation, identification techniques and medical applications of exosomes

Exosomes, which are nano-vesicles produced by most cell types, play an irreplaceable role in cell-cell communication. They are extracellular small vesicles that can delivery various cargos of DNA, RNAs, proteins, and lipids. Because exosomes have different secretory components under physiological conditions and pathological conditions, it has been extensively studied in the field of diseases as a therapeutic target, as a drug/gene delivery vector and as a novel cancer marker. Despite the great development in recent decades, there are still many obstacles to be overcome, for example, the separation method is not standardized with low yield and poor stability, which limit its medical application. This review mainly summarizes the main progresses of isolation and identification techniques, diversity function and medical application of exosomes in recent years.

MiR-223-3p promotes the proliferation, invasion and migration of colon cancer cells by negative regulating PRDM1

Colon cancer is one of the most common malignancies worldwide, while the molecular mechanism remains largely unknown. miR-223-3p plays an important role in cancer development. Here, we found that miR-223-3p was up-regulated in 30 cases of colon cancer tissues as compared with their adjacent normal tissues. Lentivirus-mediated miR-223-3p over-expression promoted the proliferation, colony formation, migration and invasion of colon cancer cells. Inverse results were observed in miR-223-3p knockdown cells. Epithelial-mesenchymal transition (EMT) was regulated by miR-223-3p. In addition, cell apoptosis was suppressed and enhanced by miR-223-3p over-expression and knockdown, respectively. We further identified PRDM1, a tumor suppressor, was the target of miR-223-3p using microarray and luciferase assay. Our findings suggested that miR-223-3p acts as an oncogenic microRNA in colon cancer through regulating EMT and PRDM1.

Neutrophil-derived miR-223 as local biomarker of bacterial peritonitis

Infection remains a major cause of morbidity, mortality and technique failure in patients with end stage kidney failure who receive peritoneal dialysis (PD). Recent research suggests that the early inflammatory response at the site of infection carries diagnostically relevant information, suggesting that organ and pathogen-specific "immune fingerprints" may guide targeted treatment decisions and allow patient stratification and risk prediction at the point of care. Here, we recorded microRNA profiles in the PD effluent of patients presenting with symptoms of acute peritonitis and show that elevated peritoneal miR-223 and reduced miR-31 levels were useful predictors of bacterial infection. Cell culture experiments indicated that miR-223 was predominantly produced by infiltrating immune cells (neutrophils, monocytes), while miR-31 was mainly derived from the local tissue (mesothelial cells, fibroblasts). miR-223 was found to be functionally stabilised in PD effluent from peritonitis patients, with a proportion likely to be incorporated into neutrophil-derived exosomes. Our study demonstrates that microRNAs are useful biomarkers of bacterial infection in PD-related peritonitis and have the potential to contribute to disease-specific immune fingerprints. Exosome-encapsulated microRNAs may have a functional role in intercellular communication between immune cells responding to the infection and the local tissue, to help clear the infection, resolve the inflammation and restore homeostasis.

Exo-miRNAs as a New Tool for Liquid Biopsy in Lung Cancer

Lung cancer is the predominant cause of cancer-related deaths. The high mortality rates are mainly due to the lack of diagnosis before the cancer is at a late stage. Liquid biopsy is a promising technique that could allow early diagnosis of lung cancer and better treatment selection for patients. Cell-free microRNAs have been detected in biological fluids, such as serum and plasma, and are considered interesting biomarkers for lung cancer screening and detection. Exosomes are nanovesicles of 30-150 nm and can be released by different cell types within the tumor microenvironment. Their exosomal composition reflects that of their parental cells and could be potentially useful as a biomarker for lung cancer diagnosis. This review summarizes the state-of-the-art of circulating microRNAs (miRNAs) in lung cancer, focusing on their potential use in clinical practice. Moreover, we describe the importance of exosomal miRNA cargo in lung cancer detection and their potential role during lung carcinogenesis. Finally, we discuss our experience with the analysis of circulating exosomal miRNAs in the bioMILD screening trial.

Basics and applications of tumor-derived extracellular vesicles

Extracellular vesicle (EV)-mediated intercellular communication acts as a critical culprit in cancer development. The selective packaging of oncogenic molecules renders tumor-derived EVs capable of altering the tumor microenvironment and thereby modulating cancer developments that may contribute to drug resistance and cancer recurrence. Moreover, the molecular and functional characteristics of cancer through its development and posttreatment evolve over time. Tumor-derived EVs are profoundly involved in this process and can, therefore, provide valuable real-time information to reflect dynamic changes occurring within the body. Because they bear unique molecular profiles or signatures, tumor-derived EVs have been highlighted as valuable diagnostic and predictive biomarkers as well as novel therapeutic targets. In addition, the use of an advanced EV-based drug delivery system for cancer therapeutics has recently been emphasized in both basic and clinical studies. In this review, we highlight comprehensive aspects of tumor-derived EVs in oncogenic processes and their potential clinical applications.

Exosomal transfer of bone marrow mesenchymal stem cell-derived miR-340 attenuates endometrial fibrosis

Bone marrow mesenchymal stem cells (BMSCs) have potential therapeutic benefits for the treatment of endometrial diseases and injury. BMSCs interact with uterus parenchymal cells by direct contact or indirect secretion of growth factors to promote functional recovery. In this study, we found that BMSC treatment in rats subjected to mechanical damage (MD) significantly increased microRNA-340 (miR-340) levels in the regenerated endometrium. Then we employed knockin and knockdown technologies to upregulate or downregulate the miR-340 level in BMSCs (miR-340⁺ BMSCs or miR-340⁻ BMSCs) and their corresponding exosomes, respectively, to test whether exosomes from BMSCs mediate miR-340 transfer. We found that the exosomes released from the primitive BMSCs or miR-340⁺ BMSCs but not miR-340⁻ BMSCs increased the miR-340 levels in primary cultured endometrial stromal cells (ESCs) compared with control. Further verification of this exosome-mediated intercellular communication was performed using exosomal inhibitor GW4869. Tagging exosomes with red fluorescent protein demonstrated that exosomes were released from BMSCs and transferred to adjacent ESCs. Compared with controls, rats receiving primitive BMSC treatment significantly improved functional recovery and downregulated collagen 1α1, α-SMA and transforming growth factor (TGF)-β1 at day 14 after MD. The outcomes were significantly enhanced by miR-340⁺ BMSC treatment, and were significantly weakened by miR-340⁻ BMSC treatment, compared with primitive BMSC treatment. In vitro studies reveal that miR-340 transferred from BMSCs suppresses the upregulated expression of fibrotic genes in ESCs induced by TGF-β1. These data suggest that the effective antifibrotic function of BMSCs is able to transfer miR-340 to ESCs by exosomes, and that enhancing the transfer of BMSC-derived miR-340 is an alternative modality in preventing intrauterine adhesion.

Summary: miR-340 in the exosomes released from BMSCs are transferred to endometrial cells, which regulate gene expression, repress endometrial fibrosis and promote functional recovery in rats subjected to mechanical damage.

Molecular model linking Th2 polarized M2 tumour-associated macrophages with deaminase-mediated cancer progression mutation signatures

A new and diverse range of somatic mutation signatures are observed in late-stage cancers, but the underlying reasons are not fully understood. We advance a "combinatorial association model" for deaminase binding domain (DBD) diversification to explain the generation of previously observed cancer-progression associated mutation signatures. We also propose that changes in the polarization of tumour-associated macrophages (TAMs) are accompanied by the expression of deaminases with a new and diverse range of DBDs, and thus accounting for the generation of new somatic mutation signatures. The mechanism proposed is molecularly reminiscent of combinatorial association of heavy (H) and light (L) protein chains following V(D)J recombination of immunoglobulin molecules (and similarly for protein chains in heterodimers α/β and γ/δ of V(D)Js of T Cell Receptors) required for pathogen antigen recognition by B cells and T cells, respectively. We also discuss whether extracellular vesicles (EVs) emanating from tumour enhancing M2-polarized macrophages represent a likely source of the de novo deaminase DBDs. We conclude that M2-polarized macrophages extruding EVs loaded with deaminase proteins or deaminase-specific transcription/translation regulatory factors and like information may directly trigger deaminase diversification within cancer cells, and thus account for the many new somatic mutation signatures that are indicative of cancer progression. This hypothesis now has a plausible evidentiary base, and it is worth direct testing in future investigations. A long-term objective would be to identify molecular biomarkers predicting cancer progression (or metastatic disease) and to support the development of new drug targets before metastatic pathways are activated.

MicroRNAs as Molecular Switches in Macrophage Activation

The efficacy of macrophage- mediated inflammatory response relies on the coordinated expression of key factors, which expression is finely regulated at both transcriptional and post-transcriptional level. Several studies have provided compelling evidence that microRNAs play pivotal roles in modulating macrophage activation, polarization, tissue infiltration, and resolution of inflammation. In this review, we highlight the essential molecular mechanisms underlying the different phases of inflammation that are targeted by microRNAs to inhibit or accelerate restoration to tissue integrity and homeostasis. We further review the impact of microRNA-dependent regulation of tumor-associated macrophages and the relative implication for tumor biology.

Lack of effective translational regulation of PLD expression and exosome biogenesis in triple-negative breast cancer cells

Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer that is difficult to treat since cells lack the three receptors (ES, PR, or HER) that the most effective treatments target. We have used a well-established TNBC cell line (MDA-MB-231) from which we found evidence in support for a phospholipase D (PLD)-mediated tumor growth and metastasis: high levels of expression of PLD, as well as the absence of inhibitory miRs (such as miR-203) and 3'-mRNA PARN deadenylase activity in these cells. Such findings are not present in a luminal B cell line, MCF-7, and we propose a new miR•PARN•PLD node that is not uniform across breast cancer molecular subtypes and as such TNBC could be pharmacologically targeted differentially. We review the participation of PLD and phosphatidic acid (PA), its enzymatic product, as new "players" in breast cancer biology, with the aspects of regulation of the tumor microenvironment, macrophage polarization, regulation of PLD transcripts by specific miRs and deadenylases, and PLD-regulated exosome biogenesis. A new signaling miR•PARN•PLD node could serve as new biomarkers for TNBC abnormal signaling and metastatic disease staging, potentially before metastases are able to be visualized using conventional imaging.

Extracellular vesicle-packaged HIF-1α-stabilizing lncRNA from tumour-associated macrophages regulates aerobic glycolysis of breast cancer cells

Metabolic reprogramming is a hallmark of cancer. Here, we demonstrate that tumour-associated macrophages (TAMs) enhance the aerobic glycolysis and apoptotic resistance of breast cancer cells via the extracellular vesicle (EV) transmission of a myeloid-specific lncRNA, HIF-1α-stabilizing long noncoding RNA (HISLA). Mechanistically, HISLA blocks the interaction of PHD2 and HIF-1α to inhibit the hydroxylation and degradation of HIF-1α. Reciprocally, lactate released from glycolytic tumour cells upregulates HISLA in macrophages, constituting a feed-forward loop between TAMs and tumour cells. Blocking EV-transmitted HISLA inhibits the glycolysis and chemoresistance of breast cancer in vivo. Clinically, HISLA expression in TAMs is associated with glycolysis, poor chemotherapeutic response and shorter survival of patients with breast cancer. Our study highlights the potential of lncRNAs as signal transducers that are transmitted between immune and tumour cells via EVs to promote cancer aerobic glycolysis.

Exosome-orchestrated hypoxic tumor microenvironment

Hypoxic tumor microenvironment is a common feature of solid tumors and is associated with aggressiveness and poor patient outcomes. A continuous interference between cancer cells and stromal cells within the hypoxic microenvironment has been uncovered for its importance in cancer development and treatment responsiveness. Exosomes, initially considered as “garbage bins” for unwanted material from cells, are now elucidated to perform a variety of functions that involve interactions within the cellular microenvironment due to their ability to carry numerous cargoes, including lipids, proteins, nucleic acids, and metabolites. Exosome-mediated continuous interference between cancer cells and stroma are believed to regulate hypoxia-adaptation and to rebuild the microenvironment in return. In this review, we will discuss the knowledge in literature with respect to the exosome-mediated multi-directional and mutual signal transmission among the variety of cell types within hypoxic cancer microenvironment.

MicroRNA Shuttle from Cell-To-Cell by Exosomes and Its Impact in Cancer

The identification of exosomes, their link to multivesicular bodies and their potential role as a messenger vehicle between cancer and healthy cells opens up a new approach to the study of intercellular signaling. Furthermore, the fact that their main cargo is likely to be microRNAs (miRNAs) provides the possibility of the transfer of such molecules to control activities in the recipient cells. This review concerns a brief overview of the biogenesis of both exosomes and miRNAs together with the movement of such structures between cells. The possible roles of miRNAs in the development and progression of breast, ovarian and prostate cancers are discussed.

miRNA-223 at the crossroads of inflammation and cancer

miR-223 is an evolutionarily conserved anti-inflammatory microRNA primarily expressed in myeloid cells. miR-223 post-transcriptionally regulates many genes essential in inflammation, cell proliferation, and invasion. Recent studies show that miR-223 is either endogenously expressed or transferred in exosomes or extracellular vesicles to non-phagocytic cells including cancer cells, where it exerts biological functions. In cancerous cells, miR-223 acts either as an oncomiR promoting tumors or as a tumor suppressor in a context-dependent manner. Taken together, miR-223 can regulate tumorigenesis at multiple levels, including by suppressing the inflammatory tumor microenvironment and modulating malignancy of cancer cells.

Role of tumor‑derived extracellular vesicles in cancer progression and their clinical applications (Review)

Extracellular vesicles (EVs), including micro‑vesicles and exosomes, are heterogeneous small membranous vesicles shed from the surface of myriad cells and are crucial in mediating intercellular communication. The vertical trafficking of cargo to the plasma membrane and subsequent redistribution of surface lipids may contribute to EV formation. Tumor‑derived extracellular vesicles (TD‑EVs) can carry complex, bioactive cargo, such as nucleic acids and proteins, during tumor metastasis. Paracrine information gets relayed by TD‑EVs to adjacent tumor cells and this allows a crosstalk between malignant cells. These structures may even move to a distant metastatic lesion and modulate the tumor microenvironment to form a premetastatic niche. Thus, TD‑EVs might be potential biomarkers for tumor development and metastasis. Additionally, EVs are promising candidates for use as cell‑free vaccines or as vehicles for the delivery of specific tumor therapeutic molecules. Genetically modified microvesicles and engineered exosomes have shed light on a novel strategy for tumor‑targeted gene therapy. This review focuses on the role of EVs in tumor development and metastasis and their possible applications in the advanced diagnosis and therapy of cancer and personalized medicine.

Exosomes from M1-Polarized Macrophages Enhance Paclitaxel Antitumor Activity by Activating Macrophages-Mediated Inflammation

Objective: Exosomes (Exos) are membrane-encased vesicles derived by nearly all cell types for intercellular communication and regulation. They also received attention for their use as natural therapeutic platforms and drug delivery system. Classically activated M1 macrophages suppress tumor growth by releasing pro-inflammatory factors. This study investigated the suitability of M1-exosomes (M1-Exos) as drug carrier and their effect on the NF-κB signal pathway and further detected whether macrophages repolarization can potentiate the antitumor activities of chemotherapeutics. Methods: M1-Exos were isolated from M1-macrophages by ultracentrifugation and characterized by transmission electron, nanoparticle tracking analysis, dynamic light scattering and western blot. Then M1-Exos were used as Paclitaxel (PTX) carriers to prepare a nano-formulation (PTX- M1-Exos). A relatively simple slight sonication method was used to prepare the drug delivery system (PTX-M1-Exos). The cytotoxicity of PTX-M1-Exos on cancer cells was detected by MTT and flow cytometry in vitro. 4T1 tumor bearing mice were used to perform the therapeutic effect of PTX-M1-Exos in vivo. Results: The expression of caspase-3 in breast cancer cells was increased when co-incubated with macrophages in the presence of M1-Exos in vitro. The production of pro-inflammatory cytokines was increased after exposure of macrophages in M1-Exos. M1-Exos provided a pro-inflammatory environment which enhanced the anti-tumor activity via caspase-3 mediated pathway. The treatment of M1-Exos to the tumor bearing mice exhibit anti-tumor effects in vivo. Meanwhile, the treatment of PTX-M1-Exos demonstrated higher anti-tumor effects than the M1-Exos or PTX group. Conclusion: The results in our study indicate that the M1-Exos act as the carrier to deliver PTX into the tumor tissues, and also enhance the anti-tumor effects of chemotherapeutics in tumor bearing mice.

Tumor-derived exosomes: Implication in angiogenesis and antiangiogenesis cancer therapy

Tumor cells utilize different strategies to communicate with neighboring tissues for facilitating tumor progression and invasion, one of these strategies has been shown to be the release of exosomes. Exosomes are small nanovesicles secreted by all kind of cells in the body, especially cancer cells, and mediate cell to cell communications. Exosomes play an important role in cancer invasiveness by harboring various cargoes that could accelerate angiogenesis. Here first, we will present an overview of exosomes, their biology, and their function in the body. Then, we will focus on exosomes derived from tumor cells as tumor angiogenesis mediators with a particular emphasis on the underlying mechanisms in various cancer origins. Also, exosomes derived from stem cells and tumor-associated macrophages will be discussed in this regard. Finally, we will discuss the novel therapeutic strategies of exosomes as drug delivery vehicles against angiogenesis.

Cross-talk between cancer cells and their neighbors via miRNA in extracellular vesicles: an emerging player in cancer metastasis

Cancer metastasis is the major cause of mortality in cancer cases and is responsible for cancer deaths. It is known that cancer cells communicate with surrounding microenvironmental cells, such as fibroblast cells, immune cells, and endothelial cells, to create a cancer microenvironment for their progression. Extracellular vesicles (EVs) are small vesicles that can be secreted by most types of cells and play an important role in cell-to-cell communications via transferring bioactive cargos, including variable RNAs, such as microRNAs (miRNAs), to recipient cells. miRNAs are a class of small noncoding RNAs that posttranscriptionally regulate gene expression. The transfer of them to recipient cells influences the metastatic process of primary tumors. In this review, we summarize the function of miRNAs packaged in EVs in cancer metastasis and discuss the clinical utility of miRNAs in EVs.

Knockdown long noncoding RNA nuclear paraspeckle assembly transcript 1 suppresses colorectal cancer through modulating miR-193a-3p/KRAS

The nuclear paraspeckle assembly transcript 1 (abbreviated as NEAT1), a nuclear sufficient long noncoding RNA (abbreviated as lncRNA), has aroused a rising concern in recent years. As uncovered by reports, the increase in NEAT1 is related to the deteriorated prognosis of lung cancer, breast cancer, hepatocellular cancer, and colorectal cancer (abbreviated as CRC). Thus far, the mechanism of NEAT1 has not been elucidated by the existing researches. The impact of knockdown of both NEAT1 and its predicted downstream miR-193a-3p in CRC cells was examined here to delve into their interactions and mechanisms. Additionally, the target of miR-193a-3p, Kirsten rat sarcoma viral oncogene homolog (abbreviated as KRAS), was also predicted by bioinformatics algorithms. Small interfering RNA and antisense oligonucleotides that inhibit NEAT1, as well as overexpression or knockdown of miR-193a-3p, were adequately drawn upon to confirm that NEAT1 serves as a miR-193a-3p sponge or competing endogenous RNA, to impact miR-193a-3p's further functions, including modulating KRAS proteins, both in vitro and in vivo. Generally, lncRNA NEAT1/hsa-miR-193a-3p/KRAS axis was substantiated in CRC cells and could provide novel insight into both diagnostic and therapeutic advancement in CRC.

Exosomes: A Promising Avenue for the Diagnosis of Breast Cancer

Currently, despite the advances in individualized treatment, breast cancer still remains the deadliest form of cancer in women. Diagnostic, prognostic, and therapy-predictive methods are mainly based on the evaluation of tumor tissue samples and are aimed to improve the overall therapeutic level. Therefore, the exploration of a series of circulating biomarkers, which serve as the information source of tumors and could be obtained by peripheral blood samples, represents a high field of interest. Apart from classical biomarkers, exosomes, which are nanovesicles, are emerging as an accessible and efficient source of cell information. The purpose of this review is to summarize the peculiarities of the presently available breast cancer exosomal biomarkers; the review also provides the prediction of a multitude of potential target genes of exosomal microRNAs using 4 databases.

Macrophage Flipping from Foe to Friend: A Matter of Interest in Breast Carcinoma Heterogeneity Driving Drug Resistance

Tumor heterogeneity within various cancer types including breast carcinoma is pivotal in the manifestations of tumor hallmarks. Tumor heterogeneity is seen as a common landscape where intra-tumoral components including cellular and non-cellular factors create an interface with outside environment that leads to the unique identity of a specific cancer type. Among various contributors to tumor heterogeneity, cellular heterogeneity immensely plays a role in drug resistance and relapse of cancer. Within cellular heterogeneity of tumor, tumor-associated macrophages (TAMs) are the pro-tumor type of immune cells that promote growth, metastasis and drug resistance in breast carcinoma and other cancer types. Revealing the molecular aspects of TAMs can provide a breakthrough to remove therapeutics blockade to existing drugs and this understanding in future will pave the way for a new class of cancer immunotherapeutic. This review addresses current understanding of the role of TAMs in breast carcinoma hallmarks and clarifies the current scenario of pre-clinical drugs directed to tame pro-cancer TAMs.

miR-125a/b inhibits tumor-associated macrophages mediated in cancer stem cells of hepatocellular carcinoma by targeting CD90

Cancer stem cells promote tumorigenesis and progression of hepatocellular carcinoma (HCC). Recently, emerging evidence indicates tumor-associated macrophages (TAMs) play an important role in tumor progression. However, TAMs often occurs with unknown mechanisms. As an important mediator in intercellular communications, exosomes secreted by host cells mediate the exchange of genetic materials and proteins, which involves tumor aggressiveness. The aim of the study was to investigate whether exosomes derived from TAMs mediate stem cell properties in HCC. TAMs were isolated from the tissues of HCC. microRNA (miRNA) expression profiles of TAMs were analyzed using miRNA microarray. In vitro cell coculture was further conducted to investigate the crosstalk between TAMs and tumor cells mediated by TAMs exosomes. In this study, we showed that TAMs exosomes promote HCC cell proliferation and stem cell properties. Using miRNA profiles assay, we identified significantly lower levels of miR-125a and miR-125b in exosomes and cell lysate isolated from TAMs. Functional studies revealed that the HCC cells were treated with TAM exosomes or transfected with miR-125a/b suppressed cell proliferation and stem cell properties by targeting CD90, a stem cell marker of HCC stem cells. The study indicated that miR-125a/b targeting CD90 played important roles in cancer stem cells of HCC.

Exosomes-the enigmatic regulators of bone homeostasis

Exosomes are a heterogeneous group of cell-derived membranous structures, which mediate crosstalk interaction between cells. Recent studies have revealed a close relationship between exosomes and bone homeostasis. It is suggested that bone cells can spontaneously secret exosomes containing proteins, lipids and nucleic acids, which then to regulate osteoclastogenesis and osteogenesis. However, the network of regulatory activities of exosomes in bone homeostasis as well as their therapeutic potential in bone injury remain largely unknown. This review will detail and discuss the characteristics of exosomes, the regulatory activities of exosomes in bone homeostasis as well as the clinical potential of exosomes in bone injury.

Vesicles known as exosomes may prove to be valuable clinical tools once their function is clarified. Exosomes were discovered in the 1980s but not observed in bone tissue until 2003. Minghao Zheng of the University of Western Australia, together with colleagues elsewhere, has reviewed the biology of exosomes, their role in maintaining bones, and their potential clinical uses. Exosomes carry lipids, proteins, and nucleic acids between cells. They are released by every type of bone cell, with the role of each exosome determined by its specific contents. Exosome-mediated crosstalk is involved in regulating bone remodeling, and exosomes have also been implicated in myelomas. Recent work has shown that exosome treatment can improve fracture healing. The authors conclude that a better understanding of the role of exosomes in bone homeostasis will unlock their significant clinical potential.

Emerging ways to treat breast cancer: will promises be met?

BACKGROUND

Breast cancer (BC) is the most common cancer among women and it is responsible for more than 40,000 deaths in the United States and more than 500,000 deaths worldwide each year. In previous decades, the development of improved screening, diagnosis and treatment methods has led to decreases in BC mortality rates. More recently, novel targeted therapeutic options, such as the use of monoclonal antibodies and small molecule inhibitors that target specific cancer cell-related components, have been developed. These components include ErbB family members (HER1, HER2, HER3 and HER4), Ras/MAPK pathway components (Ras, Raf, MEK and ERK), VEGF family members (VEGFA, VEGFB, VEGFC, VEGF and PGF), apoptosis and cell cycle regulators (BAK, BAX, BCL-2, BCL-X, MCL-1 and BCL-W, p53 and PI3K/Akt/mTOR pathway components) and DNA repair pathway components such as BRCA1. In addition, long noncoding RNA inhibitor-, microRNA inhibitor/mimic- and immunotherapy-based approaches are being developed for the treatment of BC. Finally, a novel powerful technique called CRISPR-Cas9-based gene editing is emerging as a precise tool for the targeted treatment of cancer, including BC.

CONCLUSIONS

Potential new strategies that are designed to specifically target BC are presented. Several clinical trials using these strategies are already in progress and have shown promising results, but inherent limitations such as off-target effects and low delivery efficiencies still have to be resolved. By improving the clinical efficacy of current therapies and exploring new ones, it is anticipated that novel ways to overcome BC may become attainable.

Hybrids by tumor-associated macrophages × glioblastoma cells entail nuclear reprogramming and glioblastoma invasion

Hybrid formation is a fundamental process in normal development and tissue homeostasis, while the presence and the biological role of hybrids between tumor-associated macrophages (TAMs) and glioblastoma (GBM) cells remain elusive. In this study, we observed that TAM-GBM cell hybrids existed in human GBM specimens as demonstrated by co-expression of glioma biomarkers (GFAP, IDH1^R132H and PDGFRA) and macrophage biomarkers (CD68 and CD14). Furthermore, TAM-GBM cell hybrids could also be found in C57BL/6 mice orthotopically inoculated with mouse GBM cells labeled with RFP and after co-culture of bone marrow-derived macrophages from GFP-expressed mice with RFP-labeled GBM cells. The hybrids underwent nuclear reprogramming with unique gene expression profile as compared to parental cells. Moreover, glioma invasion-associated genes were enriched in the hybrids that possessed higher invasiveness, and more hybrids in the invasive margin of GBM were observed as compared to GBM core area. Our data demonstrate the presence of TAM-GBM cell hybrids that enhance GBM invasion. With a better understanding of TAM-GBM cell hybrids, new therapeutic strategies targeting GBM will be developed to treat GBM patients.

MicroRNAs, Regulatory Messengers Inside and Outside Cancer Cells

MicroRNAs (miRNAs) are a class of short non-coding RNAs (ncRNAs) with typical sequence lengths of 19-25 nucleotides and extraordinary abilities to regulate gene expression. Because miRNAs regulate multiple important biological functions of the cell (proliferation, migration, invasion, apoptosis, differentiation, and drug resistance), their expression is highly controlled. Genetic and epigenetic alterations frequently found in cancer cells can cause aberrant expression of miRNAs and, consequently, of their target genes. The tumor microenvironment can also affect miRNA expression through soluble factors (e.g., cytokines and growth factors) secreted by either tumor cells or non-tumor cells (such as immune and stromal cells). Furthermore, like hormones, miRNAs can be secreted and regulate gene expression in recipient cells. Altered expression levels of miRNAs in cancer cells determine the acquisition of fundamental biological capabilities (hallmarks of cancer) responsible for the development and progression of the disease.

[Molecular mechanisms and relationship of M2-polarized macrophages with early response in multiple myeloma]

目的

探讨替代活化型巨噬细胞（M2 MΦ）和多发性骨髓瘤（MM）早期治疗反应的关系及其在发病机制中的可能作用。

方法

采用免疫组化法标记240例MM患者骨髓标本中的MΦ；建立体外M2 MΦ诱导培养体系，构建Transwell共培养模型与RPMI 8226和U266细胞共培养，CCK-8法检测M2 MΦ对细胞增殖的影响，流式细胞术检测对地塞米松（1 µ mol/L）诱导骨髓瘤细胞凋亡的影响，ELISA法检测对TNF-α和IL-6表达的影响，real time PCR法检测对趋化因子、血管内皮生长因子（VEGF）及其受体表达的影响。

结果

①依据骨髓组织M2 MΦ浸润程度将患者分为高浸润组（92例）和低浸润组（148例），高浸润组患者早期治疗有效率明显低于低浸润组，差异有统计学意义（23.9%对73.0%，χ²=60.31，P<0.001）。②培养24、36 h，共培养组细胞增殖能力较对照组显著上升：M2 MΦ+RPMI 8226细胞组与对照组比较，P值分别为0.005、0.020；M2 MΦ+U266细胞与对照组比较，P值分别为0.030、0.020。③地塞米松诱导后，共培养组与对照组比较，RPMI 8226细胞凋亡率下降（29.0%对71.0%，t=4.97，P=0.008），U266细胞凋亡率也下降（24.9%对67.7%，t=6.99，P=0.002）。④共培养48 h后，与对照组比较，加入M2 MΦ后可促进RPMI 8226和U266细胞分泌IL-6、TNF-α，促进表达CCL2、CCL3、CCR2、CCR5、VEGFA、VEGFR-1和VEGFR-2。

结论

MM患者骨髓组织M2 MΦ浸润程度和早期治疗反应相关。M2 MΦ通过促进骨髓瘤细胞分泌系列炎症因子、趋化因子和相关受体的表达，从而促进骨髓瘤细胞增殖以及保护骨髓瘤细胞免于凋亡。

Effect of exosomal miRNA on cancer biology and clinical applications

Exosomes, extracellular vesicles with diameters ranging from 30 to 150 nm, are widely present in various body fluids. Recently, microRNAs (miRNAs) have been identified in exosomes, the biogenesis, release, and uptake of which may involve the endosomal sorting complex required for transport (ESCRT complex) and relevant proteins. After release, exosomes are taken up by neighboring or distant cells, and the miRNAs contained within modulate such processes as interfering with tumor immunity and the microenvironment, possibly facilitating tumor growth, invasion, metastasis, angiogenesis and drug resistance. Therefore, exosomal miRNAs have a significant function in regulating cancer progression. Here, we briefly review recent findings regarding tumor-derived exosomes, including RNA sorting and delivering mechanism. We then describe the intercommunication occurring between different cells via exosomal miRNAs in tumor microenvironmnt, with impacts on tumor proliferation, vascularization, metastasis and other biological characteristics. Finally, we highlight the potential role of these molecules as biomarkers in cancer diagnosis and prognosis and tumor resistance to therapeutics.

Exosome-mediated cell-cell communication in tumor progression

Exosomes, which are 30-150 nm lipid bilayer vehicles, have been recognized as one of the most crucial components of the tumor microenvironment. Exosomes transfer specific lipid, nucleic acids, proteins and other bioactive molecules from the donor cells to the recipient cells. Accumulating evidence has suggested that cancer cells and the tumor associated stromal cells can release and receive exosomes, inside of which the components and amounts are greatly changed. Pioneering studies have revealed that these exosomes play essential roles in tumor progression. Here we summarize the recent advances in this field, by focusing on the exosome biogenesis in the cancer condition, and their biological function in angiogenesis, metastasis and chemo-resistance of tumor. The review would not only provide a summary of this field, but also insights and perspectives on exosome-based strategies in cancer diagnoses, prevention and therapy.