Dendritic cell-derived exosomes as maintenance immunotherapy after first line chemotherapy in NSCLC

Emerging Role of Extracellular Vesicles in Prostate Cancer

Prostate cancer (PCa) is the second most common cancer among men in the United States. While the use of prostate-specific antigen has improved the ability to screen and ultimately diagnose PCa, there still remain false positives due to noncancerous conditions in the prostate gland itself and other prognostic biomarkers for PCa are needed. Contents within extracellular vesicles (EVs) have emerged as promising biomarkers that can give valuable information about disease state, and have the additional benefit of being acquired through noninvasive liquid biopsies. Meaningful communication between cancer cells and the microenvironment are carried by EVs, which impact important cellular processes in prostate cancer such as metastasis, immune regulation, and drug resistance.

The roles of small extracellular vesicles in lung cancer: Molecular pathology, mechanisms, diagnostics, and therapeutics

Small extracellular vesicles (sEVs) are submicron-sized, lipid-bilayer-enclosed particles that are released from cells. A variety of tissue-specific molecules, including proteins, DNA fragments, RNA, lipids, and metabolites, can be selectively encapsulated into sEVs and delivered to nearby and distant recipient cells. Incontestable and growing evidence shows the important biological roles and the clinical relevance of sEVs in tumors. In particular, recent studies validate sEVs can be used for early tumor diagnostics, staging, and treatment monitoring. Moreover, sEVs have been used as drug delivery nanocarriers, cancer vaccines, and antigen conferrers. While still in its infancy, the field of sEV-based fundamental and translational studies has been rapidly advancing. This review comprehensively examines the latest sEV-related studies in lung cancers, encompassing extracellular vesicles and their roles in lung cancer pathophysiology, diagnostics, and therapeutics. The state-of-the-art technologies for sEV isolation, downstream molecular analyses, and sEV-based therapies indicate their potency as tools for understanding the pathology and promising clinical management of lung cancers.

Extracellular Vesicles in Blood: Sources, Effects, and Applications

Extracellular vesicles (EVs) are important players for intercellular communication. EVs are secreted by almost all cell types; they can transfer information between nearby or distant cells, and they are highly abundant in body fluids. In this review, we describe the general characteristics of EVs, as well as isolation and characterization approaches. Then, we focus on one of the most relevant sources of EVs: the blood. Indeed, apart from EVs secreted by blood cells, EVs of diverse origins travel in the bloodstream. We present the numerous types of EVs that have been found in circulation. Besides, the implications of blood-derived EVs in both physiological and pathological processes are summarized, highlighting their potential as biomarkers for the diagnosis, treatment monitoring, and prognosis of several diseases, and also as indicators of physiological modifications. Finally, the applications of EVs introduced in the circulatory system are discussed. We describe the use of EVs from distinct origins, naturally produced or engineered, autologous, allogeneic, or even from different species and the effects they have when introduced in circulation. Therefore, the present work provides a comprehensive overview of the components, effects, and applications of EVs in blood.

DC-Derived Exosomes for Cancer Immunotherapy

As the initiators of adaptive immune responses, DCs play a central role in regulating the balance between CD8 T cell immunity versus tolerance to tumor antigens. Exploiting their function to potentiate host anti-tumor immunity, DC-based vaccines have been one of most promising and widely used cancer immunotherapies. However, DC-based cancer vaccines have not achieved the promised success in clinical trials, with one of the major obstacles being tumor-mediated immunosuppression. A recent discovery on the critical role of type 1 conventional DCs (cDC1s) play in cross-priming tumor-specific CD8 T cells and determining the anti-tumor efficacy of cancer immunotherapies, however, has highlighted the need to further develop and refine DC-based vaccines either as monotherapies or in combination with other therapies. DC-derived exosomes (DCexos) have been heralded as a promising alternative to DC-based vaccines, as DCexos are more resistance to tumor-mediated suppression and DCexo vaccines have exhibited better anti-tumor efficacy in pre-clinical animal models. However, DCexo vaccines have only achieved limited clinical efficacy and failed to induce tumor-specific T cell responses in clinical trials. The lack of clinical efficacy might be partly due to the fact that all current clinical trials used peptide-loaded DCexos from monocyte-derived DCs. In this review, we will focus on the perspective of expanding current DCexo research to move DCexo cancer vaccines forward clinically to realize their potential in cancer immunotherapy.

Exosome-Based Vaccines: History, Current State, and Clinical Trials

Extracellular vesicles (EVs) are released by most cell types as part of an intracellular communication system in crucial processes such as inflammation, cell proliferation, and immune response. However, EVs have also been implicated in the pathogenesis of several diseases, such as cancer and numerous infectious diseases. An important feature of EVs is their ability to deliver a wide range of molecules to nearby targets or over long distances, which allows the mediation of different biological functions. This delivery mechanism can be utilized for the development of therapeutic strategies, such as vaccination. Here, we have highlighted several studies from a historical perspective, with respect to current investigations on EV-based vaccines. For example, vaccines based on exosomes derived from dendritic cells proved to be simpler in terms of management and cost-effectiveness than dendritic cell vaccines. Recent evidence suggests that EVs derived from cancer cells can be leveraged for therapeutics to induce strong anti-tumor immune responses. Moreover, EV-based vaccines have shown exciting and promising results against different types of infectious diseases. We have also summarized the results obtained from completed clinical trials conducted on the usage of exosome-based vaccines in the treatment of cancer, and more recently, coronavirus disease.

Biodistribution of Exosomes and Engineering Strategies for Targeted Delivery of Therapeutic Exosomes

Exosomes are cell-secreted nano-sized vesicles which deliver diverse biological molecules for intercellular communication. Due to their therapeutic potential, exosomes have been engineered in numerous ways for efficient delivery of active pharmaceutical ingredients to various target organs, tissues, and cells. In vivo administered exosomes are normally delivered to the liver, spleen, kidney, lung, and gastrointestinal tract and show rapid clearance from the blood circulation after systemic injection. The biodistribution and pharmacokinetics (PK) of exosomes can be modulated by engineering various factors such as cellular origin and membrane protein composition of exosomes. Recent advances accentuate the potential of targeted delivery of engineered exosomes even to the most challenging organs including the central nervous system. Major breakthroughs have been made related to various imaging techniques for monitoring in vivo biodistribution and PK of exosomes, as well as exosomal surface engineering technologies for inducing targetability. For inducing targeted delivery, therapeutic exosomes can be engineered to express various targeting moieties via direct modification methods such as chemically modifying exosomal surfaces with covalent/non-covalent bonds, or via indirect modification methods by genetically engineering exosome-producing cells. In this review, we describe the current knowledge of biodistribution and PK of exosomes, factors determining the targetability and organotropism of exosomes, and imaging technologies to monitor in vivo administered exosomes. In addition, we highlight recent advances in strategies for inducing targeted delivery of exosomes to specific organs and cells.

The Emerging Role of Topical Ocular Drugs to Target the Posterior Eye

The prevalence of chronic fundus diseases is increasing with the aging of the general population. The treatment of these intraocular diseases relies on invasive drug delivery because of the globular structure and multiple barriers of the eye. Frequent intraocular injections bring heavy burdens to the medical care system and patients. The use of topical drugs to treat retinal diseases has always been an attractive solution. The fast development of new materials and technologies brings the possibility to develop innovative topical formulations. This article reviews anatomical and physiological barriers of the eye which affect the bioavailability of topical drugs. In addition, we summarize innovative topical formulations which enhance the permeability of drugs through the ocular surface and/or extend the drug retention time in the eye. This article also reviews the differences of eyes between different laboratory animals to address the translational challenges of preclinical models. The fast development of in vitro eye models may provide more tools to increase the clinical translationality of topical formulations for intraocular diseases. Clinical successes of topical formulations rely on continuous and collaborative efforts between different disciplines.

Separation, characterization, and standardization of extracellular vesicles for drug delivery applications

Extracellular vesicles (EVs) are membranous nanovesicles secreted from living cells, shuttling macromolecules in intercellular communication and potentially possessing intrinsic therapeutic activity. Due to their stability, low immunogenicity, and inherent interaction with recipient cells, EVs also hold great promise as drug delivery vehicles. Indeed, they have been used to deliver nucleic acids, proteins, and small molecules in preclinical investigations. Furthermore, EV-based drugs have entered early clinical trials for cancer or neurodegenerative diseases. Despite their appeal as delivery vectors, however, EV-based drug delivery progress has been hampered by heterogeneity of sample types and methods as well as a persistent lack of standardization, validation, and comprehensive reporting. This review highlights specific requirements for EVs in drug delivery and describes the most pertinent approaches for separation and characterization. Despite residual uncertainties related to pharmacodynamics, pharmacokinetics, and potential off-target effects, clinical-grade, high-potency EV drugs might be achievable through GMP-compliant workflows in a highly standardized environment.

HLA-B and cysteinylated ligands distinguish the antigen presentation landscape of extracellular vesicles

Extracellular vesicles can modulate diverse processes ranging from proliferation and tissue repair, to chemo-resistance and cellular differentiation. With the advent of tissue and immunological targeting, extracellular vesicles are also increasingly viewed as promising vectors to deliver peptide-based cancer antigens to the human immune system. Despite the clinical relevance and therapeutic potential of such 'cell-free' approaches, the natural antigen presentation landscape exported in extracellular vesicles is still largely uncharted, due to the challenging nature of such preparations and analyses. In the context of therapeutic vesicle production, a critical evaluation of the similarity in vesicular antigen presentation is also urgently needed. In this work, we compared the HLA-I peptide ligandomes of extracellular vesicles against that of whole-cells of the same cell line. We found that extracellular vesicles not only over-represent HLA-B complexes and peptide ligands, but also cysteinylated peptides that may modulate immune responses. Collectively, these findings describe the pre-existing provision of vesicular HLA complexes that may be utilized to carry peptide vaccines, as well as the propensity for different peptide and post-translationally modified ligands to be presented, and will outline critical considerations in devising novel EV vaccination strategies.

Stem-Cell Derived Exosomes for the Treatment of Osteoarthritis

Osteoarthritis(OA) is a common degenerative orthopedic disease with multiple pathologic changes in joints affecting large populations worldwide. No treatment can reverse the progress of OA. Since exosomes were first reported in 1983, researches have been conducted to explore the mechanisms and therapeutic potential of exosomes in treating OA. Exosomes derived from Mesenchymal stem cells have attracted increasing attention in tackling the disease. This article summarizes the current advances and challenges in exosomes for OA, which may providea reference for further research.

Extracellular vesicle- and particle-mediated communication shapes innate and adaptive immune responses

Intercellular communication among immune cells is vital for the coordination of proper immune responses. Extracellular vesicles and particles (EVPs) act as messengers in intercellular communication, with important consequences for target cell and organ physiology in both health and disease. Under normal physiological conditions, immune cell-derived EVPs participate in immune responses by regulating innate and adaptive immune responses. EVPs play a major role in antigen presentation and immune activation. On the other hand, immune cell-derived EVPs exert immunosuppressive and regulatory effects. Consequently, EVPs may contribute to pathological conditions, such as autoimmune and inflammatory diseases, graft rejection, and cancer progression and metastasis. Here, we provide an overview of the role of EVPs in immune homeostasis and pathophysiology, with a particular focus on their contribution to innate and adaptive immunity and their potential use for immunotherapies.

Emerging Significance and Therapeutic Potential of Extracellular vesicles

Extracellular vesicles (EVs), are membrane-bound vesicles that have many advantages over traditional nanocarriers for drug and gene delivery. Evidence from recent studies indicate that EVs have therapeutic capability with chemical or biological modification. Tumor-derived exosomes (TEXs) were used as a new type of antigens or tumor vaccines in anti-tumor immunotherapy. With superior characteristics, modified EVs were applied to loaded and delivered synthetic drugs, silencing RNA, and microRNA for treatment. Different surface functionalization strategies have been proposed to improve the therapeutic functions of EVs. Appropriately modified EVs for disease intervention provide new avenues for effective clinical treatment strategies. Therefore, this review aimed at elucidating the therapeutic functions of EVs to generate new ideas for treatment and to unlock their hidden potential in translational medicine.

MicroRNA-320a-containing exosomes from human umbilical cord mesenchymal stem cells curtail proliferation and metastasis in lung cancer by binding to SOX4

Exosomes from human umbilical cord mesenchymal stem cells (HUCMSCs) containing microRNAs (miRNAs) have been underscored as possible therapeutic options for cancers. Hence, our goal here was to investigate the relevance of miR-320a-containing exosomes from HUCMSCs to lung cancer. First, H1299 and H460 cells were co-cultured with the exosomes overexpressing miR-320a from HUCMSCs. The data displayed that HUCMSCs-secreted exosomes expressing miR-320a exerted anti-tumor effects in vitro and in vivo. Online analysis available at TargetScan database revealed that miR-320a bound to sex-determining region Y-box 4 (SOX4), and the luciferase reporter gene assay clarified this targeting relationship. Next, a β-catenin-specific agonist WAY-262611 was delivered into the H1299 and H460 cells to assess the effects of the Wnt/β-catenin pathway on lung cancer cellular processes. The results demonstrated that WAY-262611 potentiated lung cancer cell viability, invasion, and migration, but inhibited cell apoptosis. Altogether, exosomes carrying miR-320a from HUCMSCs might suppress lung cancer cell growth via the SOX4/Wnt/β-catenin axis, which highpoints the potency of exosomes expressing miR-320a as a possible therapeutic option for lung cancer treatment.

Exosomes as Naturally Occurring Vehicles for Delivery of Biopharmaceuticals: Insights from Drug Delivery to Clinical Perspectives

Exosomes as nanosized vesicles are emerging as drug delivery systems for therapeutics owing to their natural origin, their ability to mediate intercellular communication, and their potential to encapsulate various biological molecules such as proteins and nucleic acids within the lipid bilayer membrane or in the lumen. Exosomes contain endogenous components (proteins, lipids, RNA) that could be used to deliver cargoes to target cells, offering an opportunity to diagnose and treat various diseases. Owing to their ability to travel safely in extracellular fluid and to transport cargoes to target cells with high efficacy, exosomes offer enhanced delivery of cargoes in vivo. However, several challenges related to the stabilization of the exosomes, the production of sufficient amounts of exosomes with safety and efficacy, the efficient loading of drugs into exosomes, the clearance of exosomes from circulation, and the transition from the bench scale to clinical production may limit their development and clinical use. For the clinical use of exosomes, it is important to understand the molecular mechanisms behind the transport and function of exosome vesicles. This review exploits techniques related to the isolation and characterization of exosomes and their drug delivery potential to enhance the therapeutic outcome and stabilization methods. Further, routes of administration, clinical trials, and regulatory aspects of exosomes will be discussed in this review.

Exosome-based Tumor Therapy: Opportunities and Challenges

BACKGROUND

Exosomes play an important role in transferring information among different cell types, as they transport materials from the cell membrane to the cytoplasm. They are involved not only in normal physiological functions, but also in the occurrence and development of a variety of diseases. Cancer is a major health problem affecting humans. Currently, exosomes are considered novel stars in tumor therapy.

OBJECTIVE

To present a review focusing on the role of exosomes in tumorigenesis and development and the possibility of treating tumors with exosome-targeted therapies or using exosomes as carriers.

METHODS

We reviewed literature related to the biological origin and function of exosomes and exosome-tumor relationship.

RESULTS

Exosomes are closely related to tumor immunity, angiogenesis, pre-metastasis microenvironment, chemoresistance, energy metabolism, etc. Tumor therapy involving the targeting of exosomes involves block the generation, secretion, uptake of exosomes, and elimination of circulating exosomes, and develop antitumor vaccines. Exosome as delivery vehicles can be loaded with chemotherapeutic drugs, therapeutic genes, and other therapeutic drugs to target cells. Prospects and challenges of exosome-based tumor therapy are also discussed.

CONCLUSION

Exosomes are involved in multiple processes during tumor development and should be further studied as novel targets for cancer therapy.

Exploring interactions between extracellular vesicles and cells for innovative drug delivery system design

Extracellular vesicles (EVs) are submicron cell-secreted structures containing proteins, nucleic acids and lipids. EVs can functionally transfer these cargoes from one cell to another to modulate physiological and pathological processes. Due to their presumed biocompatibility and capacity to circumvent canonical delivery barriers encountered by synthetic drug delivery systems, EVs have attracted considerable interest as drug delivery vehicles. However, it is unclear which mechanisms and molecules orchestrate EV-mediated cargo delivery to recipient cells. Here, we review how EV properties have been exploited to improve the efficacy of small molecule drugs. Furthermore, we explore which EV surface molecules could be directly or indirectly involved in EV-mediated cargo transfer to recipient cells and discuss the cellular reporter systems with which such transfer can be studied. Finally, we elaborate on currently identified cellular processes involved in EV cargo delivery. Through these topics, we provide insights in critical effectors in the EV-cell interface which may be exploited in nature-inspired drug delivery strategies.

Extracellular vesicles as antigen carriers for novel vaccination avenues

Antigen delivery has always been a challenge in scientific practice of vaccine formulation. Yet, mammalian extracellular vesicles (EVs) or bacterial membrane vesicles (MVs) provide an innovative avenue for safe and effective delivery of antigenic material. They include intrinsically loaded antigens from EV-secreting cells or extrinsically loaded antigens onto pre-formed vesicles. Interestingly, many studies shed light on potential novel anti-cancer vaccination immunotherapy for therapeutic applications from mammalian cell host-derived EVs, as well as conventional vaccination for prophylactic applications using bacterial cell-derived MVs against infectious diseases. Here, we discuss the rationale, status quo and potential for both vaccine applications using EVs.

Extracellular vesicles as drug vectors for precise cancer treatment

Extracellular vesicles (EVs) are nano-sized vesicle structures secreted from a variety of cells, which carry numerous biological macromolecules, participate in cell signal transduction and avoid immune system clearance. EVs have a plethora of specific signal recognition factors, and many studies have shown that they can play an important role in the precise treatment of tumors. This review aims to compile the applications of EVs as nanocarriers for antitumor drugs, gene drugs and other nanomaterials with anticancer capability. Additionally, we systematically summarize the preparation methodology and expound upon how to improve the drug loading and cancer-targeting capacity of EVs. We highlight that EV-based drug delivery has the potential to become the future of precise cancer treatment.

Characterization and Manipulation of the Crosstalk Between Dendritic and Natural Killer Cells Within the Tumor Microenvironment

Cellular therapy has entered the daily clinical life with the approval of CAR T cell therapeutics and dendritic cell (DCs) vaccines in the US and the EU. In addition, numerous other adoptive cellular products, including natural killer (NK) cells, are currently evaluated in early phase I/ II clinical trials for the treatment of cancer patients. Despite these promising accomplishments, various challenges remain to be mastered in order to ensure sustained therapeutic success. These include the identification of strategies by which tumor cells escape the immune system or establish an immunosuppressive tumor microenvironment (TME). As part of the innate immune system, DCs and NK cells are both present within the TME of various tumor entities. While NK cells are well known for their intrinsic anti-tumor activity by their cytotoxicity capacities and the secretion of pro-inflammatory cytokines, the role of DCs within the TME is a double-edged sword as different DC subsets have been described with either tumor-promoting or -inhibiting characteristics. In this review, we will discuss recent findings on the interaction of DCs and NK cells under physiological conditions and within the TME. One focus is the crosstalk of various DC subsets with NK cells and their impact on the progression or inhibition of tumor growth. In addition, we will provide suggestions to overcome the immunosuppressive outcome of the interaction of DCs and NK cells within the TME.

Engineering extracellular vesicles for cancer therapy: recent advances and challenges in clinical translation

Extracellular vesicles (EVs) are receiving increasing attention in recent years in the field of cancer treatment. EVs contain specific contents closely related to their donor cells, such as miRNAs, proteins and dsDNAs. As endogenous vesicles, EVs naturally have the characteristics of low toxicity and low immunogenicity and can stably pass through the circulatory system to reach the recipient cells, which make them good carriers to deliver therapeutic agents such as nucleic acid sequences and chemotherapeutics. In many preclinical studies and clinical trials, EVs have demonstrated their unlimited advantages in the field of cancer therapy. However, there are still some challenges that restrict their clinical application, such as yield, heterogeneity, safety, and specificity. In this review, we will focus on the latest breakthrough of EVs in the field of cancer treatment and discuss the challenges in the clinical translation of EVs.

Extracellular Vesicle Application as a Novel Therapeutic Strategy for Ischemic Stroke

Ischemic stroke (IS) accounts for most of the cases of stroke onset, and due to short therapeutic time window for thrombolysis and numerous limited treatment measures and contraindications, lots of patients cannot receive satisfying therapeutic effects resulting in high disability and mortality worldly. In recent years, extracellular vesicles (EVs), as nanosized membrane-structured vesicles secreted from almost all cells, especially from stem/progenitor cells, have been reported to exert significant beneficial effects on IS from multiple approaches and notably ameliorate neurological outcome. Moreover, based on nano-size and lipid bilayer structure, EVs can easily penetrate the blood-brain barrier and migrate into the brain. In this review, we mainly systematically summarize the therapeutic effects of EVs on IS and explore their potential applications. Simultaneously, we also discuss administration routines, dosages, experimental observation time, and some key issues of EV application during IS treatment. It contributes to a comprehensive understanding of the progress of EV treatment for IS and providing confident evidence for further EV clinical application widely.

Extracellular Vesicles and Their Current Role in Cancer Immunotherapy

Simple Summary

In recent years, immunotherapy has shown great advancement, becoming a powerful tool to combat cancer. In this context, the use of biologically derived vesicles has also acquired importance for cancer immunotherapy. Extracellular vesicles are thus proposed to transport molecules able to trigger an immune response and thus fight cancer cells. As a particular immunotherapeutic approach, a new technique also consists in the exploitation of extracellular vesicles as new cancer vaccines. The present review provides basic notions on cancer immunotherapy and describes several clinical trials in which therapeutic anticancer vaccines are tested. In particular, the potential of extracellular vesicles-based therapeutic vaccines in the treatment of cancer patients is highlighted, even with advanced stage-cancer. A focus on the clinical studies, already completed or still in progress, is offered and a systematic collection and reorganization of the present literature on this topic is proposed to the reader.

Abstract

Extracellular vesicles (EVs) are natural particles formed by the lipid bilayer and released from almost all cell types to the extracellular environment both under physiological conditions and in presence of a disease. EVs are involved in many biological processes including intercellular communication, acting as natural carriers in the transfer of various biomolecules such as DNA, various RNA types, proteins and different phospholipids. Thanks to their transfer and targeting abilities, they can be employed in drug and gene delivery and have been proposed for the treatment of different diseases, including cancer. Recently, the use of EVs as biological carriers has also been extended to cancer immunotherapy. This new technique of cancer treatment involves the use of EVs to transport molecules capable of triggering an immune response to damage cancer cells. Several studies have analyzed the possibility of using EVs in new cancer vaccines, which represent a particular form of immunotherapy. In the literature there are only few publications that systematically group and collectively discuss these studies. Therefore, the purpose of this review is to illustrate and give a partial reorganization to what has been produced in the literature so far. We provide basic notions on cancer immunotherapy and describe some clinical trials in which therapeutic cancer vaccines are tested. We thus focus attention on the potential of EV-based therapeutic vaccines in the treatment of cancer patients, overviewing the clinically relevant trials, completed or still in progress, which open up new perspectives in the fight against cancer.

Clinical applications for exosomes: Are we there yet?

Exosomes are a subset of extracellular vesicles essential for cell-cell communication in health and disease with the ability to transport nucleic acids, functional proteins and other metabolites. Their clinical use as diagnostic biomarkers and therapeutic carriers has become a major field of research over recent years, generating rapidly expanding scientific interest and financial investment. Their reduced immunogenicity compared to liposomes or viral vectors and their ability to cross major physiological barriers like the blood-brain barrier make them an appealing and innovative option as biomarkers and therapeutic agents. Here, we review the latest clinical developments of exosome biotechnology for diagnostic and therapeutic purposes, including the most recent COVID-19-related exosome-based clinical trials. We present current exosome engineering strategies for optimal clinical safety and efficacy, and assess the technology developed for good manufacturing practice compliant scaling up and storage approaches along with their limitations in pharmaceutical industry.

Extracellular vesicles in immunomodulation and tumor progression

Extracellular vesicles have emerged as prominent regulators of the immune response during tumor progression. EVs contain a diverse repertoire of molecular cargo that plays a critical role in immunomodulation. Here, we identify the role of EVs as mediators of communication between cancer and immune cells. This expanded role of EVs may shed light on the mechanisms behind tumor progression and provide translational diagnostic and prognostic tools for immunologists.

Exosomes and Cancer Stem Cells in Cancer Immunity: Current Reports and Future Directions

Cancer stem cells (CSCs), which have the capacity to self-renew and differentiate into various types of cells, are notorious for their roles in tumor initiation, metastasis, and therapy resistance. Thus, underlying mechanisms for their survival provide key insights into developing effective therapeutic strategies. A more recent focus has been on exosomes that play a role in transmitting information between CSCs and non-CSCs, resulting in activating CSCs for cancer progression and modulating their surrounding microenvironment. The field of CSC-derived exosomes (CSCEXs) for different types of cancer is still under exploration. A deeper understanding and further investigation into CSCEXs’ roles in tumorigenicity and the identification of novel exosomal components are necessary for engineering exosomes for the treatment of cancer. Here, we review the features of CSCEXs, including surface markers, cargo, and biological or physiological functions. Further, reports on the immunomodulatory effects of CSCEXs are summarized, and exosome engineering for CSC-targeting is also discussed.

Generation and Application of a Reporter Cell Line for the Quantitative Screen of Extracellular Vesicle Release

Extracellular vesicles (EVs) are identified as mediators of intercellular communication and cellular regulation. In the immune system, EVs play a role in antigen presentation as a part of cellular communication. To enable drug discovery and characterization of compounds that affect EV biogenesis, function, and release in immune cells, we developed and characterized a reporter cell line that allows the quantitation of EVs shed into culture media in phenotypic high-throughput screen (HTS) format. Tetraspanins CD63 and CD9 were previously reported to be enriched in EVs; hence, a construct with dual reporters consisting of CD63-Turbo-luciferase (Tluc) and CD9-Emerald green fluorescent protein (EmGFP) was engineered. This construct was transduced into the human monocytic leukemia cell line, THP-1. Cells expressing the highest EmGFP were sorted by flow cytometry as single cell, and clonal pools were expanded under antibiotic selection pressure. After four passages, the green fluorescence dimmed, and EV biogenesis was then tracked by luciferase activity in culture supernatants. The Tluc activities of EVs shed from CD63Tluc-CD9EmGFP reporter cells in the culture supernatant positively correlated with the concentrations of released EVs measured by nanoparticle tracking analysis. To examine the potential for use in HTS, we first miniaturized the assay into a robotic 384-well plate format. A 2210 commercial compound library (Maybridge) was then screened twice on separate days, for the induction of extracellular luciferase activity. The screening data showed high reproducibility on days 1 and 2 (78.6%), a wide signal window, and an excellent Z′ factor (average of 2-day screen, 0.54). One hundred eighty-seven compounds showed a response ratio that was 3SD above the negative controls in both day 1 and 2 screens and were considered as hit candidates (approximately 10%). Twenty-two out of 40 re-tested compounds were validated. These results indicate that the performance of CD63Tluc-CD9EmGFP reporter cells is reliable, reproducible, robust, and feasible for HTS of compounds that regulate EV release by the immune cells.

Therapeutic and Diagnostic Translation of Extracellular Vesicles in Cardiovascular Diseases: Roadmap to the Clinic

Exosomes are small membrane-bound vesicles of endocytic origin that are actively secreted. The potential of exosomes as effective communicators of biological signaling in myocardial function has previously been investigated, and a recent explosion in exosome research not only underscores their significance in cardiac physiology and pathology, but also draws attention to methodological limitations of studying these extracellular vesicles. In this review, we discuss recent advances and challenges in exosome research with an emphasis on scientific innovations in isolation, identification, and characterization methodologies, and we provide a comprehensive summary of web-based resources available in the field. Importantly, we focus on the biology and function of exosomes, highlighting their fundamental role in cardiovascular pathophysiology to further support potential applications of exosomes as biomarkers and therapeutics for cardiovascular diseases.

Isolation and characterization of extracellular vesicles for clinical applications in cancer - time for standardization?

Extracellular vesicles (EVs) are nanometer sized lipid enclosed particles released by all cell types into the extracellular space and biological fluids in vivo, and into cell culture media in vitro. An important physiological role of EVs is cell-cell communication. EVs interact with, and deliver, their contents to recipient cells in a functional capacity; this makes EVs desirable vehicles for the delivery of therapeutic cargoes. In addition, as EVs contain proteins, lipids, glycans, and nucleic acids that reflect their cell of origin, their potential utility in disease diagnosis and prognostication is of great interest. The number of published studies analyzing EVs and their contents in the pre-clinical and clinical setting is rapidly expanding. However, there is little standardization as to what techniques should be used to isolate, purify and characterize EVs. Here we provide a comprehensive literature review encompassing the use of EVs as diagnostic and prognostic biomarkers in cancer. We also detail their use as therapeutic delivery vehicles to treat cancer in pre-clinical and clinical settings and assess the EV isolation and characterization strategies currently being employed. Our report details diverse isolation strategies which are often dependent upon multiple factors such as biofluid type, sample volume, and desired purity of EVs. As isolation strategies vary greatly between studies, thorough EV characterization would be of great importance. However, to date, EV characterization in pre-clinical and clinical studies is not consistently or routinely adhered to. Standardization of EV characterization so that all studies image EVs, quantitate protein concentration, identify the presence of EV protein markers and contaminants, and measure EV particle size and concentration is suggested. Additionally, the use of RNase, DNase and protease EV membrane protection control experiments is recommended to ensure that the cargo being investigated is truly EV associated. Overall, diverse methodology for EV isolation is advantageous as it can support different sample types and volumes. Nevertheless, EV characterization is crucial and should be performed in a rigorous manor.

Autologous cervical tumor lysate pulsed dendritic cell stimulation followed by cisplatin treatment abrogates FOXP3+ cells in vitro

Objective

Dendritic cells (DCs) are administered as immunotherapeutic adjuvants after the completion of standard treatment in most settings. However, our Phase I trial indicated that one patient out of four, who received autologous tumor lysate-pulsed dendritic cell (TLDC) also received cisplatin chemotherapy and experienced complete regression of her lung lesion, continuing to be disease free till date. Hence, the objective of our current study is to evaluate the sustenance or augmentation of immune responses when autologous human papillomavirus positive cervical tumor lysate pulsed DC- are combined with cisplatin, using co-culture assays in vitro.

Methods

Before treatment, peripheral blood and punch biopsy samples were collected from 23 cervical cancer patients after obtaining an informed consent. DC functionality was confirmed through phenotypic and functional assays using autologous peripheral blood mononuclear cells as responders. For cisplatin experiments, the drug was added at 150, 200 (clinical dose equivalent), and 400 µM concentrations to DCs alone or DC-T cell co-cultures. Phenotypic assessment and functional characterization of DCs was done using flow cytometry. Cytokine enzyme-linked immunosorbent assay and interferon (IFN)-γ enzyme-linked immune absorbent spot assays were also performed.

Results

The functionality of TLDCs was not compromised upon cisplatin treatment in vitro even at the highest (400 μM) concentration. Even though cisplatin treatment reduced the secretion of IFN-γ and interleukin (IL)-12p40 in co-cultures stimulated with TLDCs, this effect was not significant (p>0.05). A doubling of IFN-γ secretion following cisplatin treatment was observed in at least one of three independent experiments. Additional experiments showed a reduction in both FOXP3+ regulatory T cells and IL-10 levels.

Conclusion

Our results provide evidence that cisplatin treatment may be given after autologous TLDC administration to maintain or improve a productive anti-tumor response in vaccinated patients.

Engineered Extracellular Vesicles for Cancer Therapy

Extracellular vesicles (EVs) have emerged as a novel cell-free strategy for the treatment of many diseases including cancer. As a result of their natural properties to mediate cell-to-cell communication and their high physiochemical stability and biocompatibility, EVs are considered as excellent delivery vehicles for a variety of therapeutic agents such as nucleic acids and proteins, drugs, and nanomaterials. Increasing studies have shown that EVs can be modified, engineered, or designed to improve their efficiency, specificity, and safety for cancer therapy. Herein, a comprehensive overview of the recent advances in the strategies and methodologies of engineering EVs for scalable production and improved cargo-loading and tumor-targeting is provided. Additionally, the potential applications of engineered EVs in cancer therapy are discussed by presenting prominent examples, and the opportunities and challenges for translating engineered EVs into clinical practice are evaluated.

Characterization of βARKct engineered cellular extracellular vesicles and model specific cardioprotection

Recent data supporting any benefit of stem cell therapy for ischemic heart disease have suggested paracrine-based mechanisms via extracellular vesicles (EVs) including exosomes. We have previously engineered cardiac-derived progenitor cells (CDCs) to express a peptide inhibitor, βARKct, of G protein-coupled receptor kinase 2, leading to improvements in cell proliferation, survival, and metabolism. In this study, we tested whether βARKct-CDC EVs would be efficacious when applied to stressed myocytes in vitro and in vivo. When isolated EVs from βARKct-CDCs and control GFP-CDCs were added to cardiomyocytes in culture, they both protected against hypoxia-induced apoptosis. We tested whether these EVs could protect the mouse heart in vivo, following exposure either to myocardial infarction (MI) or acute catecholamine toxicity. Both types of EVs significantly protected against ischemic injury and improved cardiac function after MI compared with mice treated with EVs from mouse embryonic fibroblasts; however, βARKct EVs treated mice did display some unique beneficial properties including significantly altered pro- and anti-inflammatory cytokines. Importantly, in a catecholamine toxicity model of heart failure (HF), myocardial injections of βARKct-containing EVs were superior at preventing HF compared with control EVs, and this catecholamine toxicity protection was recapitulated in vitro. Therefore, introduction of the βARKct into cellular EVs can have improved reparative properties in the heart especially against catecholamine damage, which is significant as sympathetic nervous system activity is increased in HF.NEW & NOTEWORTHY βARKct, the peptide inhibitor of GRK2, improves survival and metabolic functions of cardiac-derived progenitor cells. As any benefit of stem cells in the ischemic and injured heart suggests paracrine mechanisms via secreted EVs, we investigated whether CDC-βARKct engineered EVs would show any benefit over control CDC-EVs. Compared with control EVs, βARKct-containing EVs displayed some unique beneficial properties that may be due to altered pro- and anti-inflammatory cytokines within the vesicles.

Emerging role and therapeutic application of exosome in hepatitis virus infection and associated diseases

Hepatitis viruses are chief pathogens of hepatitis and end-stage liver diseases. Their replication and related pathogenic process highly rely on the host micro-environment and multiple cellular elements, including exosomes. Representing with a sort of cell-derived vesicle structure, exosomes were considered to be dispensable cellular components, even wastes. Along with advancing investigation, a specific profile of exosome in driving hepatitis viruses' infection and hepatic disease progression is revealed. Exosomes greatly affect the pathogenesis of hepatitis viruses by mediating their replication and modulating the host immune responses. The characteristics of host exosomes are markedly changed after infection with hepatitis viruses. Exosomes released from hepatitis virus-infected cells can carry viral nucleic or protein components, thereby acting as an effective subterfuge for hepatitis viruses by participating in viral transportation and immune escape. On the contrary, immune cell-derived exosomes contribute toward the innate antiviral immune defense and virus eradication. There is growing evidence supporting the application of exosomal biomarkers for predicting disease progress or therapeutic outcome, while exosomal nanoshuttles are regarded as promising therapeutic options based on their delivery properties and immune compatibility. In this review, we summarize the biogenesis and secretion mechanism of exosomes, review the recent findings pertaining to the role of exosomes in the interplay between hepatitis viruses and innate immune responses, and conclude their potential in further therapeutic application.

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

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

Platform technologies and human cell lines for the production of therapeutic exosomes

Exosomes are extracellular vesicles secreted by most cell types and represent various biological properties depending on their producing cells. They are also known to be important mediators of intercellular communication. Recent data suggest that exosomes can mediate the therapeutic effects of their parental cells; hence, they have been in the spotlight as novel therapeutics. To develop and manufacture effective therapeutic exosomes, customized strategies are needed to use appropriate technologies for exosome engineering and to select suitable production cell lines. In this review, we provide an overview of currently available exosome engineering platform technologies for loading active pharmaceutical ingredient cargo and the types of human cells/cell lines that are being used as exosome-producing cells, particularly focusing on their characteristics, advantages, and disadvantages.

Exosomes and cancer: from molecular mechanisms to clinical applications

Exosomes are extracellular nanovesicles secreted from almost all types of normal and cancer cells. Collective evidence suggests that exosomes participate in cell-cell communication via transmitting their cargo, including nucleic acids, proteins, and metabolites to recipient cells. Tumor-derived exosomes (TEXs) play prominent roles in the regulation of molecular pathways in malignancies. Internalization of exosomes by tumor cells affects cellular pathways and several cancer hallmarks, including reprogramming of stromal cells, modulating immune responses, reconstructing extracellular matrix architecture, or even endowing tumor cells with drug features resistance. The unique biogenesis pathways of exosomes, their composition, low immunogenicity, and nontoxicity, together with their ability to target tumor cells, bring them up as an attractive vesicles for cancer therapy. Thus, understanding the molecular mechanisms of exosomes' participation in tumorigenesis will be critical for the next generation of cancer therapeutics. This review aims to summarize the exosomes' roles in different mechanisms underlying cancer progression for the rational design of tailored strategies against this illness. The present study also highlights the new findings on using these smart vesicles as therapeutic targets and potential biomarkers. Recent advances in exosome biology will open up new, more effective, less invasive, and more individualized clinical applications for treating cancer patients.

Small Extracellular Vesicles: A Novel Avenue for Cancer Management

Extracellular vesicles are small membrane particles derived from various cell types. EVs are broadly classified as ectosomes or small extracellular vesicles, depending on their biogenesis and cargoes. Numerous studies have shown that EVs regulate multiple physiological and pathophysiological processes. The roles of small extracellular vesicles in cancer growth and metastasis remain to be fully elucidated. As endogenous products, small extracellular vesicles are an ideal drug delivery platform for anticancer agents. However, several aspects of small extracellular vesicle biology remain unclear, hindering the clinical implementation of small extracellular vesicles as biomarkers or anticancer agents. In this review, we summarize the utility of cancer-related small extracellular vesicles as biomarkers to detect early-stage cancers and predict treatment outcomes. We also review findings from preclinical and clinical studies of small extracellular vesicle-based cancer therapies and summarize interventional clinical trials registered in the United States Food and Drug Administration and the Chinese Clinical Trials Registry. Finally, we discuss the main challenges limiting the clinical implementation of small extracellular vesicles and recommend possible approaches to address these challenges.

An updated review on exosomes: biosynthesis to clinical applications

Exosomes are membrane-based extracellular vesicles naturally released by the cells. Nano size range of exosomes and unique properties such as stability, biocompatibility and low immunogenicity are key parameters, which make them suitable as nanoparticulate drug delivery system and also considered as promising delivery carriers for future clinical use. This review outlines the composition, biogenesis, isolation and characterisation methods along with biological and clinical applications of exosomes. Further, the biopharmaceutical features of exosomes include loading method, modified exosomes and potential use of exosomes for different diseases are well explained with the current case studies. We well elaborate the future directions for clinical use of exosomes as drug delivery platforms.

Role of extracellular vesicles in chronic lung disease

To explore the role of extracellular vesicles (EVs) in chronic lung diseases.

EVs are emerging as mediators of intercellular communication and possible diagnostic markers of disease. EVs harbour cargo molecules including RNA, lipids and proteins that they transfer to recipient cells. EVs are intercellular communicators within the lung microenvironment. Due to their disease-specific cargoes, EVs have the promise to be all-in-one complex multimodal biomarkers. EVs also have potential as drug carriers in chronic lung disease.

Descriptive discussion of key studies of EVs as contributors to disease pathology, as biomarkers and as potential therapies with a focus on chronic obstructive pulmonary disorder (COPD), cystic fibrosis (CF), asthma, idiopathic pulmonary fibrosis and lung cancer.

We provide a broad overview of the roles of EV in chronic respiratory disease. Recent advances in profiling EVs have shown their potential as biomarker candidates. Further studies have provided insight into their disease pathology, particularly in inflammatory processes across a spectrum of lung diseases. EVs are on the horizon as new modes of drug delivery and as therapies themselves in cell-based therapeutics.

EVs are relatively untapped sources of information in the clinic that can help further detail the full translational nature of chronic lung disorders.

Multifunctional Applications of Engineered Extracellular Vesicles in the Treatment of Cancer

Extracellular vesicles (EVs) are key players of intercellular communication in the physiological and pathological setting. In cancer, EVs mediate complex signaling mechanisms between cancer cells and the tumor microenvironment (TME), and can influence tumor progression and the response to existing therapies. Importantly, EVs can be loaded with therapeutic agents and modified to display tumor-targeting molecules. In the field of nanomedicine, EVs have been engineered to serve as therapeutic delivery vehicles for several anticancer agents, including antibodies, chemotherapy, compounds, CRISPR/Cas9 (clustered regularly interspaced short palindromic repeats-associated endonuclease 9), and small interfering RNA (siRNA). Notably, the engineered EVs were shown to suppress malignant features of cancer cells, to elicit antitumor immunity, and to decrease tumor angiogenesis. Here, we review the EV-based therapies designed to target cancer cells and to educate components of the TME to drive antitumor responses. These studies illustrate the multifunctional applications of EVs in the development of anticancer therapies and their translational potential for cancer treatment.

Small extracellular vesicles-based cell-free strategies for therapy

Small extracellular vesicles (sEVs) are extracellular nanovesicles that contain bioactive proteins, lipids, RNA, and DNA. A variety of biological process is regulated with sEVs. sEVs are an intercellular messenger regulating recipient cell function and play a role in disease initiation and progression. sEVs derived from certain cells, such as mesenchymal stem cells and immune cells, have the potential for clinical therapy as they possess the characteristics of their parental cells. With better understanding of sEVs biogenesis, their transportation properties, extended circulatory capability, and exceptional biocompatibility, sEVs emerge as a potential therapeutic tool in the clinic. Here, we summarize applications of sEVs-based therapies in different diseases and current knowledge about the strategies in bioengineered sEVs, as well as the challenges for their use in clinical settings.

Emerging role of exosomes and exosomal microRNA in cancer: pathophysiology and clinical potential

BACKGROUND

Exosomes are extracellular nanometric vesicles used by cells to communicate with each other. They are responsible for many pathological conditions, including tumors by transferring regulatory biomolecules that impact target cell activity. Because of their high concentration in exosomes compared with parental cells and the rest of exosomal content, specificity to the cell of origin, and their well-organized sorting mechanism, microRNAs (miRNAs) are thought to be the most potent exosomes cargo and used by scientists to track exosomes and to detect cell activity changes and prognosis in cancer early.

PURPOSE

In this review, the results of studies examining the role of exosomes in cancer pathophysiology and their clinical potential are discussed in detail. Tumor-derived exosomes (TDEs) mediate the dynamic changes of cancer growth and invasion, including local microenvironment remodeling, distance metastasis, angiogenesis, and tumor-associated immunosuppression. They also contribute to hypoxia-induced tumor progression and cancer cell drug resistance. As a result of exosomes being present in all body fluids, it is possible to have early accessible and less-invasive diagnostic and prognostic measures by forming a table for each cancer type and its matched specific miRNAs. Under testing, available therapeutic uses of exosomes include interference of exosomes biogenesis, secretion, or uptake, and recruitment of exosomes as target-specific drug delivery vehicles, and immunostimulatory agents for both cancer patients and healthy population to avoid cancer development from the start.

CONCLUSION

These data suggest that exosomes and exosomal microRNA are directly related to cancer progression mechanisms, and could be used in cancer early diagnosis, prognosis, and therapy.

Diagnostic and Therapeutic Applications of Exosome Nanovesicles in Lung Cancer: State-of-The-Art

Lung cancer is a malignant disease with a frequency of various morbidity, mortality, and poor prognosis in patients that the conventional therapeutic approaches are not efficient sufficiently. Recently, with the discovery of exosomes, researchers have examined new approaches in the development, diagnosis, treatment, and drug delivery of various cancer, such as lung cancer, and display various its potential. Investigation of exosome-derived lung cancer cells contents and preparation of their exhaustive profile by advanced technics such as labeling exosome with nanoparticle and types of mass spectroscopy methods will assist researchers for take advantage of the specific properties of exosomes. Moreover, scientists will present encouraging ways for the treatment of lung cancer with loaded of drugs, proteins, microRNA, and siRNA in specific antigen targeted exosomes. This manuscript will include brief details on the role of exosomes as a novel prognostic biomarker (by the content of lipid, surface and internal protein, miRNAs, and LnRNAs) and therapeutic agent (as vaccine and targeted drug delivery) in lung cancer.

Cell-derived vesicles for delivery of cancer immunotherapy

In recent years, cancer immunotherapy has received unprecedented attention due to the clinical achievements. The applications of biomedical engineering and materials science to cancer immunotherapy have solved the challenges caused by immunotherapy to a certain extent. Among them, cell-derived vesicles are natural biomaterials chosen as carriers or immune-engineering in view of their many unique advantages. This review will briefly introduce the recent applications of cell-derived vesicles for cancer immunotherapy.

Cell-derived vesicles for delivery of cancer immunotherapy

In recent years, cancer immunotherapy has received unprecedented attention due to the clinical achievements. The applications of biomedical engineering and materials science to cancer immunotherapy have solved the challenges caused by immunotherapy to a certain extent. Among them, cell-derived vesicles are natural biomaterials chosen as carriers or immune-engineering in view of their many unique advantages. This review will briefly introduce the recent applications of cell-derived vesicles for cancer immunotherapy.

Biocompatible exosomes nanodrug cargo for cancer cell bioimaging and drug delivery

Therapy against cancer remains a daunting issue for human health, despite remarkable innovations in many areas of pathology. In situ biosynthesized nanoclusters bestow a novel remedy for carcinogenic cell imaging. Exosomes have received special attention as an efficient tool for the diagnosis of various diseases, including cancers. All types of cells (healthy or diseased) generate exosomes, making them significantly unique for relevant disease diagnosis and treatment. In this contribution, we exploit the possibility of utilizing the exosomes to facilitate chemotherapeutics, viz. the combination of doxorubicin (Dox) and biosynthesized silver nanoclusters in cancer cells. Our study showed a new facile way for bioimaging of cancer cells using biosynthesized silver-DNA nanoclusters, and thus further targeting cancer cells using the relevant cancer exosomes as drug delivery cargo. After isolating exosomes from neoplastic cells, i.e. HeLa, loaded with the drug, and treating other neoplastic cells with cargo-loaded isolated exosomes, we found that cargo-loaded isolated exosomes can readily enter into the targeted cancer cells and efficiently kill these neoplastic cells. This raises the possibility of acting as a novel facile modality for target cancer theranostics with high efficiency and biocompability.

Membrane vesicles nanotheranostic systems: sources, engineering methods, and challenges

Extracellular vesicles (EVs) are cell secretory native components with long-circulation, good biocompatibility, and physiologic barriers cross ability. EVs derived from different donor cells inherit varying characteristics and functions from their original cells and are favorable to serve as vectors for diagnosing and treating various diseases. However, EVs nanotheranostics are still in their infancy because of their limited accumulation at lesion sites and compromised therapy efficiency. Hence, engineering modification of EVs is usually needed to further enhance their stability, biological activity, and lesion-targeting capacity. Herein, we overview the characteristics of EVs from different sources, as well as the latest developments of surface engineering and cargo loading methods. We also focus especially on advances in EVs-based disease theranostics. At the end of the review, we predict the obstacles and prospects of the future clinical application of EVs.

Secreted Ligands of the NK Cell Receptor NKp30: B7-H6 Is in Contrast to BAG6 Only Marginally Released via Extracellular Vesicles

NKp30 (Natural Cytotoxicity Receptor 1, NCR1) is a powerful cytotoxicity receptor expressed on natural killer (NK) cells which is involved in tumor cell killing and the regulation of antitumor immune responses. Ligands for NKp30, including BAG6 and B7-H6, are upregulated in virus-infected and tumor cells but rarely detectable on healthy cells. These ligands are released by tumor cells as part of the cellular secretome and interfere with NK cell activity. BAG6 is secreted via the exosomal pathway, and BAG6-positive extracellular vesicles (EV-BAG6) trigger NK cell cytotoxicity and cytokine release, whereas the soluble protein diminishes NK cell activity. However, the extracellular format and activity of B7-H6 remain elusive. Here, we used HEK293 as a model cell line to produce recombinant ligands and to study their impact on NK cell activity. Using this system, we demonstrate that soluble B7-H6 (sB7-H6), like soluble BAG6 (sBAG6), inhibits NK cell-mediated target cell killing. This was associated with a diminished cell surface expression of NKG2D and NCRs (NKp30, NKp40, and NKp46). Strikingly, a reduced NKp30 mRNA expression was observed exclusively in response to sBAG6. Of note, B7-H6 was marginally released in association with EVs, and EVs collected from B7-H6 expressing cells did not stimulate NK cell-mediated killing. The molecular analysis of EVs on a single EV level using nano flow cytometry (NanoFCM) revealed a similar distribution of vesicle-associated tetraspanins within EVs purified from wildtype, BAG6, or B7-H6 overexpressing cells. NKp30 is a promising therapeutic target to overcome NK cell immune evasion in cancer patients, and it is important to unravel how extracellular NKp30 ligands inhibit NK cell functions.

Recent Advancement and Technical Challenges in Developing Small Extracellular Vesicles for Cancer Drug Delivery

Extracellular vesicles (EVs) are a heterogeneous population of lipid bilayer membrane-enclosed vesicles and act like 'messages in a bottle' in cell-cell communication by transporting their cargoes to recipient cells. Small EVs (sEVs, < 200 nm) are highly researched recently and have been harnessed as novel delivery systems for the treatment of various diseases, including neurodegenerative disorders, cardiovascular diseases, and most importantly cancer primarily because of their non-immunogenicity, tissue penetration and cell-tropism. This review will first provide a comprehensive overview of sEVs regarding the current understanding on their properties, biogenesis, new classification by the ISEV, composition, as well as their roles in cancer development (thereby called "oncosomes"). The primary focus will be given to the current state of sEVs as natural nanocarriers for cancer drug delivery, the technologies and challenges involved in sEV isolation and characterization, therapeutic cargo loading, and surface modification to enhance tumor-targeting. We will also provide examples of sEV products under clinical trials. Furthermore, the current challenges as well as the advance in "sEV mimetics" to address some of the sEVs limitations is briefly discussed. We seek to advance our understanding of sEVs to unlock their full potential as superior drug delivery vehicles in cancer therapy.

Regulation of Antitumor Immune Responses by Exosomes Derived from Tumor and Immune Cells

Exosomes are lipid membrane-enclosed vesicles released by all cell types that act at the paracrine or endocrine level to favor cell differentiation, tissue homeostasis, organ remodeling and immune regulation. Their biosynthesis begins with a cell membrane invagination which generates an early endosome that matures to a late endosome. By inward budding of the late endosome membrane, a multivesicular body (MVB) with intraluminal vesicles (ILVs) is generated. The fusion of MVBs with the plasma membrane releases ILVs into the extracellular space as exosomes, ranging in size from 30 to 100 nm in diameter. The bilipid exosome membrane is rich in cholesterol, ceramides and phosphatidylserine and can be loaded with DNA, RNA, microRNAs, proteins and lipids. It has been demonstrated that exosome secretion is a common mechanism used by the tumor to generate an immunosuppressive microenvironment that favors cancer development and progression, allowing tumor escape from immune control. Due to their ability to transport proteins, lipids and nucleic acids from the cell that gave rise to them, exosomes can be used as a source of biomarkers with great potential for clinical applications in diagnostic, prognostic or therapeutic areas. This article will review the latest research findings on exosomes and their contribution to cancer development.

A Comprehensive Review on Factors Influences Biogenesis, Functions, Therapeutic and Clinical Implications of Exosomes

Exosomes are nanoscale-sized membrane vesicles secreted by almost all cell types into the extracellular environment upon fusion of multivesicular bodies and plasma membrane. Biogenesis of exosomes is a protein quality control mechanism, and once released, exosomes transmit signals to other cells. The applications of exosomes have increased immensely in biomedical fields owing to their cell-specific cargos that facilitate intercellular communications with neighboring cells through the transfer of biologically active compounds. The diverse constituents of exosomes reflect their cell of origin and their detection in biological fluids represents a diagnostic marker for various diseases. Exosome research is expanding rapidly due to the potential for clinical application to therapeutics and diagnosis. However, several aspects of exosome biology remain elusive. To discover the use of exosomes in the biomedical applications, we must better understand the basic molecular mechanisms underlying their biogenesis and function. In this comprehensive review, we describe factors involved in exosomes biogenesis and the role of exosomes in intercellular signaling and cell-cell communications, immune responses, cellular homeostasis, autophagy, and infectious diseases. In addition, we discuss the role of exosomes as diagnostic markers, and their therapeutic and clinical implications. Furthermore, we addressed the challenges and outstanding developments in exosome research, and discuss future perspectives.