Tumor-derived nanovesicles promote lung distribution of the therapeutic nanovector through repression of Kupffer cell-mediated phagocytosis

Bibliometric and visualized analysis of the applications of exosomes based drug delivery

Exosomes, endogenous vesicles secreted by cells, possess unique properties like high biocompatibility, low immunogenicity, targeting ability, long half-life, and blood-brain barrier permeability. They serve as crucial intercellular communication vectors in physiological processes and disease occurrence. Our comprehensive analysis of exosome-based drug delivery research from 2013 to 2023 revealed 2,476 authors from 717 institutions across 33 countries. Keyword clustering identified five research areas: drug delivery, mesenchymal stem cells, cancer immunotherapy, targeting ligands, surface modifications, and macrophages. The combination of exosome drug delivery technology with a proven clinical model enables the precise targeting of tumors with chemotherapy or radiosensitising agents, as well as facilitating gene therapy. This bibliometric analysis aims to characterize the current state and advance the clinical application of exosome-based drug delivery systems.

The engineered exosomes targeting ferroptosis: A novel approach to reverse immune checkpoint inhibitors resistance

Immune checkpoint inhibitors (ICIs) have been extensively used in immunological therapy primarily due to their ability to prolong patient survival. Although ICIs have achieved success in cancer treatment, the resistance of ICIs should not be overlooked. Ferroptosis is a newly found cell death mode characterized by the accumulation of reactive oxygen species (ROS), glutathione (GSH) depletion, and glutathione peroxidase 4 (GPX4) inactivation, which has been demonstrated to be beneficial to immunotherapy and combining ferroptosis and ICIs to exploit new immunotherapies may reverse ICIs resistance. Exosomes act as mediators in cell-to-cell communication that may regulate ferroptosis to influence immunotherapy through the secretion of biological molecules. Thus, utilizing exosomes to target ferroptosis has opened up exciting possibilities for reversing ICIs resistance. In this review, we summarize the mechanisms of ferroptosis improving ICIs therapy and how exosomes regulate ferroptosis through adjusting iron metabolism, blocking the ROS accumulation, controlling ferroptosis defense systems, and influencing classic signaling pathways and how engineered exosomes target ferroptosis and improve ICIs efficiency.

Biological Roles and Clinical Applications of Exosomes in Breast Cancer: A Brief Review

Breast cancer (BC) is a global health risk for women and has a high prevalence rate. The drug resistance, recurrence, and metastasis of BC affect patient prognosis, thus posing a challenge to scientists. Exosomes are extracellular vesicles (EVs) that originate from various cells; they have a double-layered lipid membrane structure and contain rich biological information. They mediate intercellular communication and have pivotal roles in tumor development, progression, and metastasis and drug resistance. Exosomes are important cell communication mediators in the tumor microenvironment (TME). Exosomes are utilized as diagnostic and prognostic biomarkers for estimating the treatment efficacy of BC and have the potential to function as tools to enable the targeted delivery of antitumor drugs. This review introduces recent progress in research on how exosomes influence tumor development and the TME. We also present the research progress on the application of exosomes as prognostic and diagnostic biomarkers and drug delivery tools.

Application of exosomes in tumor immunity: recent progresses

Exosomes are small extracellular vesicles secreted by cells, ranging in size from 30 to 150 nm. They contain proteins, nucleic acids, lipids, and other bioactive molecules, which play a crucial role in intercellular communication and material transfer. In tumor immunity, exosomes present various functions while the following two are of great importance: regulating the immune response and serving as delivery carriers. This review starts with the introduction of the formation, compositions, functions, isolation, characterization, and applications of exosomes, and subsequently discusses the current status of exosomes in tumor immunotherapy, and the recent applications of exosome-based tumor immunity regulation and antitumor drug delivery. Finally, current challenge and future prospects are proposed and hope to demonstrate inspiration for targeted readers in the field.

A New Paradigm in Spinal Cord Injury Therapy: from Cell-free Treatment to Engineering Modifications

Spinal cord injury (SCI) is an intractable and poorly prognostic neurological disease, and current treatments are still unable to cure it completely and avoid sequelae. Extracellular vesicles (EVs), as important carriers of intercellular communication and pharmacological effects, are considered to be the most promising candidates for SCI therapy because of their low toxicity and immunogenicity, their ability to encapsulate endogenous bioactive molecules (e.g., proteins, lipids, and nucleic acids), and their ability to cross the blood-brain/cerebrospinal barriers. However, poor targeting, low retention rate, and limited therapeutic efficacy of natural EVs have bottlenecked EVs-based SCI therapy. A new paradigm for SCI treatment will be provided by engineering modified EVs. Furthermore, our limited understanding of the role of EVs in SCI pathology hinders the rational design of novel EVbased therapeutic approaches. In this study, we review the pathophysiology after SCI, especially the multicellular EVs-mediated crosstalk; briefly describe the shift from cellular to cell-free therapies for SCI treatment; discuss and analyze the issues related to the route and dose of EVs administration; summarize and present the common strategies for EVs drug loading in the treatment of SCI and point out the shortcomings of these drug loading methods; finally, we analyze and highlight the feasibility and advantages of bio-scaffold-encapsulated EVs for SCI treatment, providing scalable insights into cell-free therapy for SCI.

Aptamer-modified tetrahedral DNA nanostructure-immobilized liposome for specific gene delivery and potential cancer theragnostic

Targeted delivery of therapeutic agents to cancer cells is crucial for effective cancer treatment without adverse effects. In this study, we developed a novel delivery carrier, Aptamer-modified tetrahedral DNA nanostructure (TDN) immobilized Liposome (ApTL), for specific delivery to nucleolin-overexpressing cancer cells. We demonstrated that targeted ApTL was highly effective in delivering plasmid and mRNA to nucleolin-overexpressing cancer cells compared to non-targeted ApTL with a non-specific aptamer. ApTL, which is highly negative and nano-sized, specifically delivered nucleic acids to MDA-MB-231 and HeLa cancer cells, primarily via lipid-raft-mediated endocytosis. Furthermore, the co-delivery of mRNA and doxorubicin resulted in increased apoptosis and reduced cancer cell viability. Interestingly, co-delivery of mRNA and Dox did not show a significant difference in EGFP expression at 24 h but dramatically increased EGFP expression at 48 h, making ApTL/mEGFP/Dox a promising candidate for detecting live cancer cells after targeted cancer drug treatment. Our results suggest that ApTL can be a promising tool for the targeted delivery of therapeutic agents to nucleolin-overexpressing cancer cells, providing a new strategy for cancer theragnostic.

Tumor-derived systems as novel biomedical tools-turning the enemy into an ally

Cancer is a complex illness that presents significant challenges in its understanding and treatment. The classic definition, "a group of diseases characterized by the uncontrolled growth and spread of abnormal cells in the body," fails to convey the intricate interaction between the many entities involved in cancer. Recent advancements in the field of cancer research have shed light on the role played by individual cancer cells and the tumor microenvironment as a whole in tumor development and progression. This breakthrough enables the utilization of the tumor and its components as biological tools, opening new possibilities. This article delves deeply into the concept of "tumor-derived systems", an umbrella term for tools sourced from the tumor that aid in combatting it. It includes cancer cell membrane-coated nanoparticles (for tumor theranostics), extracellular vesicles (for tumor diagnosis/therapy), tumor cell lysates (for cancer vaccine development), and engineered cancer cells/organoids (for cancer research). This review seeks to offer a complete overview of the tumor-derived materials that are utilized in cancer research, as well as their current stages of development and implementation. It is aimed primarily at researchers working at the interface of cancer biology and biomedical engineering, and it provides vital insights into this fast-growing topic.

Studying exogenous extracellular vesicle biodistribution by in vivo fluorescence microscopy

Extracellular vesicles (EVs) are lipid-bound vesicles released from cells that play a crucial role in many physiological processes and pathological mechanisms. As such, there is great interest in their biodistribution. One currently accessible technology to study their fate in vivo involves fluorescent labelling of exogenous EVs followed by whole-animal imaging. Although this is not a new technology, its translation from studying the fate of whole cells to subcellular EVs requires adaptation of the labelling techniques, excess dye removal and a refined experimental design. In this Review, we detail the methods and considerations for using fluorescence in vivo and ex vivo imaging to study the biodistribution of exogenous EVs and their roles in physiology and disease biology.

Formation of pre-metastatic niches induced by tumor extracellular vesicles in lung metastasis

There are a number of malignant tumors that metastasize into the lung as one of their most common sites of dissemination. The successful infiltration of tumor cells into distant organs is the result of the cooperation between tumor cells and distant host cells. When tumor cells have not yet reached distant organs, in situ tumor cells secrete extracellular vesicles (EVs) carrying important biological information. In recent years, scholars have found that tumor cells-derived EVs act as the bridge between orthotopic tumors and secondary metastases by promoting the formation of a pre-metastatic niche (PMN), which plays a key role in awakening dormant circulating tumor cells and promoting tumor cell colonization. This review provides an overview of multiple routes and mechanisms underlying PMN formation induced by EVs and summaries study findings that underline a potential role of EVs in the intervention of lung PMN, both as a target or a carrier for drug design. In this review, the underlying mechanisms of EVs in lung PMN formation are highlighted as well as potential applications to lung metastasis diagnosis and treatment.

The Roles of Exosomes in the Diagnose, Development and Therapeutic Resistance of Oral Squamous Cell Carcinoma

Oral cancer is one of the most common cancers worldwide, of which more than half of patients are diagnosed at a locally advanced stage with poor prognosis due to recurrence, metastasis and resistant to treatment. Thus, it is imperative to further explore the potential mechanism of development and drug resistance of oral cancer. Exosomes are small endosome-derived lipid nanoparticles that are released by cells. Since the cargoes of exosomes were inherited from their donor cells, the cargo profiles of exosomes can well recapitulate that of their donor cells. This is the theoretical basis of exosome-based liquid biopsy, providing a tool for early diagnosis of oral cancer. As an important intracellular bioactive cargo delivery vector, exosomes play a critical role in the development of oral cancer by transferring their cargoes to receipt cells. More importantly, recent studies have revealed that exosomes could induce therapy-resistance in oral cancer through multiple ways, including exosome-mediated drug efflux. In this review, we summarize and compare the role of exosomes in the diagnosis, development and therapy-resistant of oral cancer. We also highlight the clinical application of exosomes, and discuss the advantages and challenges of exosomes serving as predictive biomarker, therapy target and therapy vector in oral cancer.

Tumor-derived extracellular vesicles for the active targeting and effective treatment of colorectal tumors in vivo

Colorectal cancer remains one of the main causes of cancer-related deaths worldwide. Although numerous nanomedicine formulations have been developed to tackle the disease, their low selectivity still limits effective therapeutic outcomes. In this study, we isolated extracellular vesicles (EVs) from CT26 colorectal cancer cells and 4T1 murine mammary carcinoma cells, loaded them with the chemotherapeutic agent (doxorubicin, DOX). Then we evaluated the cellular uptake of the extracellular vesicles both in 2D monolayer and 3D tumor spheroid setups using confocal laser scanning microscope and flow cytometry. In vivo tumor homing of the extracellular vesicles was verified on CT26 tumor bearing BALB/c mice using in vivo imaging system. Finally, in vivo therapeutic effects were evaluated and compared using the same animal models treated with five doses of EV formulations. CT26-EV-DOX exhibited excellent biocompatibility, a high drug-loading capacity, controlled drug release behavior, and a high capability for targeting colorectal cancer cells. In particular, we verified that CT26-EV-DOX could preferentially be up taken by their parent cells and could effectively target and penetrate 3D tumor spheroids resembling colorectal tumors in vivo in comparison with their 4T1 derived EV partner. Additionally, treatment of colorectal tumor-bearing BALB/c mice with of CT26-EV-DOX significantly inhibited the growth of the tumors during the treatment course. The developed CT26-EV-DOX nanoparticles may present a novel and effective strategy for the treatment of colorectal cancer.

Illuminating the Molecular Intricacies of Exosomes and ncRNAs in Cardiovascular Diseases: Prospective Therapeutic and Biomarker Potential

Cardiovascular diseases (CVDs) are one of the leading causes of death worldwide. Accumulating evidences have highlighted the importance of exosomes and non-coding RNAs (ncRNAs) in cardiac physiology and pathology. It is in general consensus that exosomes and ncRNAs play a crucial role in the maintenance of normal cellular function; and interestingly it is envisaged that their potential as prospective therapeutic candidates and biomarkers are increasing rapidly. Considering all these aspects, this review provides a comprehensive overview of the recent understanding of exosomes and ncRNAs in CVDs. We provide a great deal of discussion regarding their role in the cardiovascular system, together with providing a glimpse of ideas regarding strategies exploited to harness their potential as a therapeutic intervention and prospective biomarker against CVDs. Thus, it could be envisaged that a thorough understanding of the intricacies related to exosomes and ncRNA would seemingly allow their full exploration and may lead clinical settings to become a reality in near future.

The roles of small extracellular vesicles as prognostic biomarkers and treatment approaches in triple-negative breast cancer

Triple-negative breast cancer (TNBC) is a particularly aggressive and invasive breast cancer subtype and is associated with poor clinical outcomes. Treatment approaches for TNBC remain limited partly due to the lack of expression of well-known molecular targets. Small extracellular vesicles (sEVs) carrying a variety of bioactive contents play an important role in intercellular communications. The biomolecules including nucleic acids, proteins, and metabolites can be transferred locally or systematically to recipient cells and regulate their biological states and are involved in physiological and pathological processes. Recently, despite the extensive attraction to the physiological functions of sEVs, few studies focus on the roles of sEVs in TNBC. In this review, we will summarize the involvement of sEVs in the tumor microenvironment of TNBC. Moreover, we will discuss the potential roles of sEVs as diagnostic markers and treatment therapy in this heterogeneous breast cancer subtype. We finally summarize the clinical application of sEVs in TNBC.

Mesenchymal Stem Cell-Derived Extracellular Vesicles as Idiopathic Pulmonary Fibrosis Microenvironment Targeted Delivery

Idiopathic pulmonary fibrosis (IPF) affects an increasing number of people globally, yet treatment options remain limited. At present, conventional treatments depending on drug therapy do not show an ideal effect in reversing the lung damage or extending the lives of IPF patients. In recent years, more and more attention has focused on extracellular vesicles (EVs) which show extraordinary therapeutic effects in inflammation, fibrosis disease, and tissue damage repair in many kinds of disease therapy. More importantly, EVs can be modified or used as a drug or cytokine delivery tool, targeting injury sites to enhance treatment efficiency. In light of this, the treatment strategy of mesenchymal stem cell-extracellular vesicles (MSC-EVs) targeting the pulmonary microenvironment for IPF provides a new idea for the treatment of IPF. In this review, we summarized the inflammation, immune dysregulation, and extracellular matrix microenvironment (ECM) disorders in the IPF microenvironment in order to reveal the treatment strategy of MSC-EVs targeting the pulmonary microenvironment for IPF.

Nano-Messengers of the Heart: Promising Theranostic Candidates for Cardiovascular Maladies

Till date, cardiovascular diseases remain a leading cause of morbidity and mortality across the globe. Several commonly used treatment methods are unable to offer safety from future complications and longevity to the patients. Therefore, better and more effective treatment measures are needed. A potential cutting-edge technology comprises stem cell-derived exosomes. These nanobodies secreted by cells are intended to transfer molecular cargo to other cells for the establishment of intercellular communication and homeostasis. They carry DNA, RNA, lipids, and proteins; many of these molecules are of diagnostic and therapeutic potential. Several stem cell exosomal derivatives have been found to mimic the cardioprotective attributes of their parent stem cells, thus holding the potential to act analogous to stem cell therapies. Their translational value remains high as they have minimal immunogenicity, toxicity, and teratogenicity. The current review highlights the potential of various stem cell exosomes in cardiac repair, emphasizing the recent advancements made in the development of cell-free therapeutics, particularly as biomarkers and as carriers of therapeutic molecules. With the use of genetic engineering and biomimetics, the field of exosome research for heart treatment is expected to solve various theranostic requirements in the field paving its way to the clinics.

Non-Coding RNAs Delivery by Small Extracellular Vesicles and Their Applications in Ovarian Cancer

Ovarian cancer (OC) is the most fatal gynecological malignancy because of its early asymptomatic nature and acquired resistance to chemotherapy. Small extracellular vesicles (sEVs) are a heterogeneous group of biological vesicles with a diameter <200 nm released by cells under physiological or pathological conditions. sEVs-derived non-coding RNAs (ncRNAs) are the essential effectors in the biological environment. sEVs-ncRNAs have critical roles in tumor progression via regulating mRNA expression of target cells to affect cell signaling. In addition, the status of parental cells can be disclosed via analyzing the composition of sEVs-ncRNAs, and their “cargoes” with specific changes can be used as key biomarkers for the diagnosis and prognosis of OC. Accumulating evidence has demonstrated that sEVs-ncRNAs are involved in multiple key processes that mediate the development of metastasis and chemotherapeutic resistance in OC: epithelial–mesenchymal transition; tumorigenicity of mesenchymal stem cells; immune evasion; angiogenesis. The nanomedicine delivery system based on engineering sEVs is expected to be a novel therapeutic strategy for OC. Insights into the biological roles of sEVs-ncRNAs in the invasion, metastasis, immune regulation, and chemoresistance of OC will contribute to discovery of novel biomarkers and molecular targets for early detection and innovative therapy. In this review, we highlight recent advances and applications of sEVs-ncRNAs in OC diagnosis and treatment. We also outline current challenges and knowledge gaps.

Exosome-Based Nanoplatforms: The Emerging Tools for Breast Cancer Therapy

Breast cancer (BC) remains the leading malignant tumor type among females worldwide. The patients with BC are still faced with undesirable metastasis, relapse rate, and drug resistance. Exosomes are defined as naturally occurring extracellular vesicles (EVs) with typical biomarkers that reflect the characteristics of the parent cells. Exosomes are crucial mediators involved in intercellular communication. By transferring multiple cargoes, represented by proteins, nucleic acids, lipids, metabolites, exosomes contribute to reshaping the recipient cell function and fate. Growing evidence has documented that exosomes originating from BC cells are important participants involved in BC progression and treatments. Nanoparticle-based technology is the cutting-edge field for renewing pharmaceuticals and has endowed deep improvements in precise BC treatment. Additionally, due to their perfect features of the low immune prototype, limited adverse effects, prolongated circulation, and easy modification, exosomes have received much attention as candidates in nano-medicine of BC. The nanoplatforms constructed by exosomes have safety, intelligence, biomimetic, and controlled released advantages for combating BC. Here, we emphasize the multiple exosomes from a variety of cell sources in constructing nanoplatforms for BC therapy, mainly including exosomes and their cargoes, genetically engineered exosomes, and exosome-based carriers. This field would shed light on the promising exosome-based delivery system in BC therapy.

Nanoparticle based medicines: approaches for evading and manipulating the mononuclear phagocyte system and potential for clinical translation

For decades, nanomedicines have been reported as a potential means to overcome the limitations of conventional drug delivery systems by reducing side effects, toxicity and the non-ideal pharmacokinetic behaviour typically exhibited by small molecule drugs. However, upon administration many nanoparticles prompt induction of host inflammatory responses due to recognition and uptake by macrophages, eliminating up to 95% of the administered dose. While significant advances in nanoparticle engineering and consequent therapeutic efficacy have been made, it is becoming clear that nanoparticle recognition by the mononuclear phagocyte system (MPS) poses an impassable junction in the current framework of nanoparticle development. Hence, this has negative consequences on the clinical translation of nanotechnology with respect to therapeutic efficacy, systemic toxicity and economic benefit. In order to improve the translation of nanomedicines from bench-to-bedside, there is a requirement to either modify nanomedicines in terms of how they interact with intrinsic processes in the body, or modulate the body to be more accommodating for nanomedicine treatments. Here we provide an overview of the current standard for design elements of nanoparticles, as well as factors to consider when producing nanomedicines that have minimal MPS-nanoparticle interactions; we explore this landscape across the cellular to tissue and organ levels. Further, rather than designing materials to suit the body, a growing research niche involves modulating biological responses to administered nanomaterials. We here discuss how developing strategic methods of MPS 'pre-conditioning' with small molecule or biological drugs, as well as implementing strategic dosing regimens, such as 'decoy' nanoparticles, is essential to increasing nanoparticle therapeutic efficacy. By adopting such a perspective, we hope to highlight the increasing trends in research dedicated to improving nanomedicine translation, and subsequently making a positive clinical impact.

Human Amniotic Epithelial Cells Secretome: Components, Bioactivity, and Challenges

Human amniotic epithelial cells (hAECs) derived from placental tissue have received significant attention as a promising tool in regenerative medicine. Several studies demonstrated their anti-inflammatory, anti-fibrotic, and tissue repair potentials. These effects were further shown to be retained in the conditioned medium of hAECs, suggesting their paracrine nature. The concept of utilizing the hAEC-secretome has thus evolved as a therapeutic cell-free option. In this article, we review the different components and constituents of hAEC-secretome and their influence as demonstrated through experimental studies in the current literature. Studies examining the effects of conditioned medium, exosomes, and micro-RNA (miRNA) derived from hAECs are included in this review. The challenges facing the application of this cell-free approach will also be discussed based on the current evidence.

Extracellular vesicles as delivery systems at nano-/micro-scale

Extracellular vesicles (EVs) have shown significant promises as nano-/micro-size carriers in drug delivery and bioimaging. With more characteristics of EVs explored through tremendous research efforts, their unmatched physicochemical properties, biological features, and mechanical aspects make them unique vehicles, owning exceptional pharmacokinetics, circulatory metabolism and biodistribution pattern when delivering theranostic cargoes. In this review we firstly analyzed pros and cons of the EVs as a delivery platform. Secondly, compared to engineered nanoparticle delivery systems, such as biocompatible di-block co-polymers, rational design to improve EVs (exosomes in particular) were elaborated. Lastly, different pharmaceutical loading approaches into EVs were compared, reaching a conclusion on how to construct a clinically available and effective nano-/micro-carrier for a satisfactory medical mission.

Strategies for Engineering Exosomes and Their Applications in Drug Delivery

Exosomes are representative of a promising vehicle for delivery of biomolecules. Despite their discovery nearly 40 years, knowledge of exosomes and extracellular vesicles (EVs) and the role they play in etiology of disease and normal cellular physiology remains in its infancy. EVs are produced in almost all cells, containing nucleic acids, lipids, and proteins delivered from donor cells to recipient cells. Consequently, they act as mediators of intercellular communication and molecular transfer. Recent studies have shown that, exosomes are associated with numerous physiological and pathological processes as a small subset of EVs, and they play a significant role in disease progression and treatment. In this review, we discuss several key questions: what are exosomes, why do they matter, and how do we repurpose them in their strategies and applications in drug delivery systems. In addition, opportunities and challenges of exosome-based theranostics are also described and directions for future research are presented.

miR-151a-3p-rich small extracellular vesicles derived from gastric cancer accelerate liver metastasis via initiating a hepatic stemness-enhancing niche

Liver metastasis (LM) severely affects gastric cancer (GC) patients' prognosis. Small extracellular vesicles (sEVs) play key roles in intercellular communication. Specific sEV-miRNAs from several types of cancer were found to induce a premetastatic niche in target organs before tumor cell arrive. However, whether the primary GC affects hepatic microenvironment or the role of sEV-miRNAs in GC-LM is yet unclear. We report that GC-derived sEVs are primarily absorbed by Kupffer cells (KCs). sEV-miR-151a-3p is highly expressed in GC-LM patients' plasma and presents poor prognosis. Treating mice with sEVs-enriched in miR-151a-3p promotes GC-LM, whereas has no influence on the proliferation of GC cells in situ. Mechanistically, sEV-miR-151a-3p inhibits SP3 in KCs. Simultaneously, sEV-miR-151a-3p targets YTHDF3 to decrease the transcriptional inhibitory activity of SP3 by reducing SUMO1 translation in a N6-methyladenosine-dependent manner. These factors contribute to TGF-β1 transactivation in KCs, subsequently activating the SMAD2/3 pathway and enhancing the stem cell-like properties of incoming GC cells. Furthermore, sEV-miR-151a-3p induces miR-151a-3p transcription in KCs to form a positive feedback loop. In summary, our results reveal a previously unidentified regulatory axis initiated by sEV-miR-151a-3p that establishes a hepatic stemness-permissive niche to support GC-LM. sEV-miR-151a-3p could be a promising diagnostic biomarker and preventive treatment candidate for GC-LM.

Vitamin E-facilitated carbon monoxide pro-drug nanomedicine for efficient light-responsive combination cancer therapy

The quest to maximize therapeutic efficiency in cancer treatment requires innovative delivery nanoplatforms capable of employing different modules simultaneously. Combination therapy has proven to be one of the best anticancer strategies so far. Herein, we have developed a lipid-encapsulated nanoplatform that combines chemotherapy with photoresponsive gas therapy for colon cancer treatment. Carbon monoxide releasing molecules (CORMs) and vitamin E analogues (pure/pegylated α-tocopheryl succinate; α-TOS) were co-loaded into the lipid layer with core-shell upconversion nanoparticles (UCNPs), which converted 808 nm light to 360 nm photons to trigger CO release at the tumor site. This folic acid (FA)-targeting nanomedicine (Lipid/UCNP/CORM/α-TOS/FA: LUCTF) possessed a cancer-targeting ability and a light-triggered CO release ability for synergistic apoptosis of HCT116 cells via enhanced ROS generation and mitochondrial membrane breaking. In vivo data have confirmed the significantly enhanced therapeutic efficacy of LUCTF without any significant biosafety issues after intravenous administration. Thus, nanomedicine LUCTF represents a novel way for efficient cancer therapy via combining locally released CO and a compatible chemotherapeutic agent (e.g. α-TOS).

Designer exosomes for targeted and efficient ferroptosis induction in cancer via chemo-photodynamic therapy

Background: Efficient and specific induction of cell death in liver cancer is urgently needed. In this study, we aimed to design an exosome-based platform to deliver ferroptosis inducer (Erastin, Er) and photosensitizer (Rose Bengal, RB) into tumor tissues with high specificity. Methods: Exosome donor cells (HEK293T) were transfected with control or CD47-overexpressing plasmid. Exosomes were isolated and loaded with Er and RB via sonication method. Hepa1-6 cell xenograft C57BL/6 model was injected with control and engineered exosomes via tail vein. In vivo distribution of the injected exosomes was analyzed via tracking the fluorescence labeled exosomes. Photodynamic therapy was conducted by 532 nm laser irradiation. The therapeutic effects on hepatocellular carcinoma and toxic side-effects were systemically analyzed. Results: CD47 was efficiently loaded on the exosomes from the donor cells when CD47 was forced expressed by transfection. CD47 surface functionalization (ExosCD47) made the exosomes effectively escape the phagocytosis of mononuclear phagocyte system (MPS), and thus increased the distribution in tumor tissues. Erastin and RB could be effectively encapsulated into exosomes after sonication, and the drug-loaded exosomes (Er/RB@ExosCD47) strongly induced ferroptosis both in vitro and in vivo in tumor cells after irradiation of 532 nm laser. Moreover, compared with the control exosomes (Er/RB@ExosCtrl), Er/RB@ExosCD47 displayed much lower toxicity in liver. Conclusion: The engineered exosomes composed of CD47, Erastin, and Rose Bengal, induce obvious ferroptosis in hepatocellular carcinoma (HCC) with minimized toxicity in liver and kidney. The proposed exosomes would provide a promising strategy to treat types of malignant tumors.

The Potential Application of Magnetic Nanoparticles for Liver Fibrosis Theranostics

Liver fibrosis is a major cause of morbidity and mortality worldwide due to chronic liver damage and leading to cirrhosis, liver cancer, and liver failure. To date, there is no effective and specific therapy for patients with hepatic fibrosis. As a result of their various advantages such as biocompatibility, imaging contrast ability, improved tissue penetration, and superparamagnetic properties, magnetic nanoparticles have a great potential for diagnosis and therapy in various liver diseases including fibrosis. In this review, we focus on the molecular mechanisms and important factors for hepatic fibrosis and on potential magnetic nanoparticles-based therapeutics. New strategies for the diagnosis of liver fibrosis are also discussed, with a summary of the challenges and perspectives in the translational application of magnetic nanoparticles from bench to bedside.

RGD-Binding Integrins Revisited: How Recently Discovered Functions and Novel Synthetic Ligands (Re-)Shape an Ever-Evolving Field

Simple Summary

Integrins, a superfamily of cell adhesion receptors, were extensively investigated as therapeutic targets over the last decades, motivated by their multiple functions, e.g., in cancer (progression, metastasis, angiogenesis), sepsis, fibrosis, and viral infections. Although integrin-targeting clinical trials, especially in cancer, did not meet the high expectations yet, integrins remain highly interesting therapeutic targets. In this article, we analyze the state-of-the-art knowledge on the roles of a subfamily of integrins, which require binding of the tripeptide motif Arg-Gly-Asp (RGD) for cell adhesion and signal transduction, in cancer, in tumor-associated exosomes, in fibrosis and SARS-CoV-2 infection. Furthermore, we outline the latest achievements in the design and development of synthetic ligands, which are highly selective and affine to single integrin subtypes, i.e., αvβ3, αvβ5, α5β1, αvβ6, αvβ8, and αvβ1. Lastly, we present the substantial progress in the field of nuclear and optical molecular imaging of integrins, including first-in-human and clinical studies.

Abstract

Integrins have been extensively investigated as therapeutic targets over the last decades, which has been inspired by their multiple functions in cancer progression, metastasis, and angiogenesis as well as a continuously expanding number of other diseases, e.g., sepsis, fibrosis, and viral infections, possibly also Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV-2). Although integrin-targeted (cancer) therapy trials did not meet the high expectations yet, integrins are still valid and promising targets due to their elevated expression and surface accessibility on diseased cells. Thus, for the future successful clinical translation of integrin-targeted compounds, revisited and innovative treatment strategies have to be explored based on accumulated knowledge of integrin biology. For this, refined approaches are demanded aiming at alternative and improved preclinical models, optimized selectivity and pharmacological properties of integrin ligands, as well as more sophisticated treatment protocols considering dose fine-tuning of compounds. Moreover, integrin ligands exert high accuracy in disease monitoring as diagnostic molecular imaging tools, enabling patient selection for individualized integrin-targeted therapy. The present review comprehensively analyzes the state-of-the-art knowledge on the roles of RGD-binding integrin subtypes in cancer and non-cancerous diseases and outlines the latest achievements in the design and development of synthetic ligands and their application in biomedical, translational, and molecular imaging approaches. Indeed, substantial progress has already been made, including advanced ligand designs, numerous elaborated pre-clinical and first-in-human studies, while the discovery of novel applications for integrin ligands remains to be explored.

Prospects and challenges of extracellular vesicle-based drug delivery system: considering cell source

Extracellular vesicles (EVs), including exosomes, microvesicles, and apoptotic bodies, are nanosized membrane vesicles derived from most cell types. Carrying diverse biomolecules from their parent cells, EVs are important mediators of intercellular communication and thus play significant roles in physiological and pathological processes. Owing to their natural biogenesis process, EVs are generated with high biocompatibility, enhanced stability, and limited immunogenicity, which provide multiple advantages as drug delivery systems (DDSs) over traditional synthetic delivery vehicles. EVs have been reported to be used for the delivery of siRNAs, miRNAs, protein, small molecule drugs, nanoparticles, and CRISPR/Cas9 in the treatment of various diseases. As a natural drug delivery vectors, EVs can penetrate into the tissues and be bioengineered to enhance the targetability. Although EVs' characteristics make them ideal for drug delivery, EV-based drug delivery remains challenging, due to lack of standardized isolation and purification methods, limited drug loading efficiency, and insufficient clinical grade production. In this review, we summarized the current knowledge on the application of EVs as DDS from the perspective of different cell origin and weighted the advantages and bottlenecks of EV-based DDS.

Exosome-based Ldlr gene therapy for familial hypercholesterolemia in a mouse model

Familial hypercholesterolemia (FH), with high LDL (low-density lipoprotein) cholesterol levels, is due to inherited mutations in genes, such as low-density lipoprotein receptor (LDLR). Development of therapeutic strategies for FH, which causes atherosclerosis and cardiovascular disease, is urgently needed.

Methods: Mice with low-density lipoprotein receptor (Ldlr) deletion (Ldlr^-/- mice) were used as an FH model. Ldlr mRNA was encapsulated into exosomes by forced expression of Ldlr in the donor AML12 (alpha mouse liver) cells, and the resultant exosomes were denoted as Exo^Ldlr. In vivo distribution of exosomes was analyzed by fluorescence labeling and imaging. The delivery efficiency of Ldlr mRNA was analyzed by qPCR and Western blotting. Therapeutic effects of Exo^Ldlr were examined in Ldlr^-/- mice by blood lipids and Oil Red O staining.

Results: The encapsulated mRNA was stable and could be translated into functional protein in the recipient cells. Following tail vein injection, exosomes were mainly delivered into the liver, producing abundant LDLR protein, resembling the endogenous expression profile in the wild-type mouse. Compared with control exosomes, Exo^Ldlr treatment significantly decreased lipid deposition in the liver and lowered the serum LDL-cholesterol level. Significantly, the number and size of atherosclerotic plaques and inflammation were reduced in the Exo^Ldlr-treated mice.

Conclusions: We have shown that exosome-mediated Ldlr mRNA delivery effectively restored receptor expression, treating the disorders in the Ldlr^-/- mouse. Our study provided a new therapeutic approach for the treatment of FH patients and managing atherosclerosis.

Breast cancer exosomes contribute to pre-metastatic niche formation and promote bone metastasis of tumor cells

Rationale: Breast cancer preferentially develops osteolytic bone metastasis, which makes patients suffer from pain, fractures and spinal cord compression. Accumulating evidences have shown that exosomes play an irreplaceable role in pre-metastatic niche formation as a communication messenger. However, the function of exosomes secreted by breast cancer cells remains incompletely understood in bone metastasis of breast cancer. Methods: Mouse xenograft models and intravenous injection of exosomes were applied for analyzing the role of breast cancer cell-derived exosomes in vivo. Effects of exosomes secreted by the mildly metastatic MDA231 and its subline SCP28 with highly metastatic ability on osteoclasts formation were confirmed by TRAP staining, ELISA, microcomputed tomography, histomorphometric analyses, and pit formation assay. The candidate exosomal miRNAs for promoting osteoclastogenesis were globally screened by RNA-seq. qRT-PCR, western blot, confocal microscopy, and RNA interfering were performed to validate the function of exosomal miRNA. Results: Implantation of SCP28 tumor cells in situ leads to increased osteoclast activity and reduced bone density, which contributes to the formation of pre-metastatic niche for tumor cells. We found SCP28 cells-secreted exosomes are critical factors in promoting osteoclast differentiation and activation, which consequently accelerates bone lesion to reconstruct microenvironment for bone metastasis. Mechanistically, exosomal miR-21 derived from SCP28 cells facilitates osteoclastogenesis through regulating PDCD4 protein levels. Moreover, miR-21 level in serum exosomes of breast cancer patients with bone metastasis is significantly higher than that in other subpopulations. Conclusion: Our results indicate that breast cancer cell-derived exosomes play an important role in promoting breast cancer bone metastasis, which is associated with the formation of pre-metastatic niche via transferring miR-21 to osteoclasts. The data from patient samples further reflect the significance of miR-21 as a potential target for clinical diagnosis and treatment of breast cancer bone metastasis.

Targeted delivery of extracellular vesicles in heart injury

Extracellular vesicles (EVs) are nanoscale extracellular vesicles derived from endocytosis that are crucial to intercellular communication. EVs possess natural biocompatibility and stability that allow them to cross biological membranes and that protect them from degradation. Recent studies have shown that EVs-mediated crosstalk between different cell types in the heart could play important roles in the maintenance of cardiac homeostasis and the pathogenesis of heart diseases. In particular, EVs secreted by different types of stem cells exhibit cardioprotective effects. However, numerous studies have shown that intravenously injected EVs are quickly cleared by macrophages of the mononuclear phagocyte system (MPS) and preferentially accumulate in MPS organs such as the liver, spleen, and lung. In this review, we discuss exosome biogenesis, the role of EVs in heart diseases, and challenges in delivering EVs to the heart. Furthermore, we extensively discuss the targeted delivery of EVs for treating ischemic heart disease. These understandings will aid in the development of effective treatment strategies for heart diseases.

Recent Advances in Extracellular Vesicles as Drug Delivery Systems and Their Potential in Precision Medicine

Extracellular vesicles (EVs) are membrane-bilayered nanoparticles released by most cell types. Recently, an enormous number of studies have been published on the potential of EVs as carriers of therapeutic agents. In contrast to systems such as liposomes, EVs exhibit less immunogenicity and higher engineering potential. Here, we review the most relevant publications addressing the potential and use of EVs as a drug delivery system (DDS). The information is divided based on the key steps for designing an EV-mediated delivery strategy. We discuss possible sources and isolation methods of EVs. We address the administration routes that have been tested in vivo and the tissue distribution observed. We describe the current knowledge on EV clearance, a significant challenge towards enhancing bioavailability. Also, EV-engineering approaches are described as alternatives to improve tissue and cell-specificity. Finally, a summary of the ongoing clinical trials is performed. Although the application of EVs in the clinical practice is still at an early stage, a high number of studies in animals support their potential as DDS. Thus, better treatment options could be designed to precisely increase target specificity and therapeutic efficacy while reducing off-target effects and toxicity according to the individual requirements of each patient.

The Function of Astrocyte Mediated Extracellular Vesicles in Central Nervous System Diseases

Astrocyte activation plays an important role during disease-induced inflammatory response in the brain. Exosomes in the brain could be released from bone marrow (BM)-derived stem cells, neuro stem cells (NSC), mesenchymal stem cells (MSC), etc. We summarized that exosomes release and transport signaling to the target cells, and then produce function. Furthermore, we discussed the pathological interactions between astrocytes and other brain cells, which are related to brain diseases such as stroke, Alzheimer’s disease (AD), Parkinson’s disease (PD), amyotrophic lateral sclerosis (ALS) disease, multiple sclerosis (MS), psychiatric, traumatic brain injury (TBI), etc. We provide up-to-date, comprehensive and valuable information on the involvement of exosomes in brain diseases, which is beneficial for basic researchers and clinical physicians.

Exosome vesicle as a nano-therapeutic carrier for breast cancer

Breast cancer (BC) is one of the most common lethal diseases found in women; in which shortcomings of currently used treatment procedures and efficiency to target disease contribute to the increment in mortality. Despite other factors, exosomes, a major class of EVs (extracellular vesicles) also play a regulatory role in normal physiological processes and have a major function in proliferation, metastases, and resistance in BC. Interestingly, despite their role in the progression of BC, exosomes also showed their importance as a drug carrier in the targeted drug delivery. The present review aims to shed light on the role of exosomes as a potential nano-therapeutic vehicle in the targeted drug delivery for BC. Information for this review was searched from PubMed and Google Scholar mostly during the year 2019-2020 by using appropriate keywords. The exosomes have been efficiently used in cancer therapeutics where these nano vehicles having specific markers help in efficient targeted delivery of therapeutics including proteins, nucleic acid, and anti-cancer drugs to BC cells. The properties of exosomes as an efficient delivery system can be explored in the future and holds the potential to be used in other forms of cancer as well.

Biomimetic nanovesicle design for cardiac tissue repair

Cardiovascular disease is a major cause of mortality and morbidity worldwide. Exosome therapies are promising for cardiac repair. Exosomes transfer cargo between cells, have high uptake by native cells and are ideal natural carriers for proteins and nucleic acids. Despite their proreparative potential, exosome production is dependent on parent cell state with typically low yields and cargo variability. Therefore, there is potential value in engineering exosomes to maximize their benefits by delivering customized, potent cargo for cardiovascular disease. Here, we outline several methods of exosome engineering focusing on three important aspects: optimizing cargo, homing to target tissue and minimizing clearance. Finally, we put these methods in context of the cardiac field and discuss the future potential of vesicle design.

Exosomes: A Potential Therapeutic Tool Targeting Communications between Tumor Cells and Macrophages

Exosomes comprise extracellular vesicles (EVs) with diameters between 30 and 150 nm. They transfer proteins, RNA, and other molecules from cell to cell, playing an important role in the interactions between cells. The tumor microenvironment (TME) has been found to contain various cells and molecules that have an important impact on tumor development. In the TME, macrophages have been found to have an important relationship with tumor cells, with tumors recruiting and inducing macrophages to become tumor-associated macrophages (TAMs), which promote tumor development. Recently, exosomes have been found to play a critical role in the interaction between tumor cells and macrophages. Thus, in this review, we summarize the roles and mechanisms of exosomes in the interaction between tumor cells and macrophages and the potential methods by which exosomes are used to target the communication between tumor cells and macrophages to treat cancer.

Kupffer cells promote T-cell hepatitis by producing CXCL10 and limiting liver sinusoidal endothelial cell permeability

Rationale: Kupffer cells (KCs) play a crucial role in liver immune homeostasis through interacting with other immune cells and liver sinusoidal endothelial cells (LSECs). However, how KCs exactly interact with these cells for maintaining the homeostasis still require the further investigation. CXCL10 is a chemokine that has been implicated in chemoattraction of monocytes, T cells, NK cells, and dendritic cells, and promotion of T cell adhesion to endothelial cells. Although CXCL10 is also known to participate in the pathogenesis of hepatic inflammation, the degree to which it is functionally involved in the crosstalk between immune cells and regulation of immune response is still unclear.

Methods: To dynamically investigate the function of KCs, we used our recently developed rapid cell ablation model, intermedilysin (ILY)/human CD59 (hCD59)-mediated cell ablation tool, to selectively ablate KC pool under normal condition or concanavalin A (Con A)- induced hepatitis. At certain time points after KCs ablation, we performed flow cytometry to monitor the amount of hepatic infiltrating immune cells. mRNA array was used to detect the change of hepatic cytokines and chemokines levels. Cytokines and chemokines in the serum were further measured by LEGENDplex^TM mouse proinflammatory chemokine panel and inflammation panel. Evans blue staining and transmission electron microscopy were used to investigate the interaction between KCs and LSECs in steady condition. CXCL10 neutralizing antibody and CXCL10 deficient mouse were used to study the role of CXCL10 in immune cell migration and pathogenesis of Con A-induced hepatitis.

Results: At steady state, elimination of KCs results in a reduction of hepatic infiltrating monocytes, T, B, and NK cells and a list of cytokines and chemokines at transcriptional level. In the meantime, the depletion of KCs resulted in increased sinusoidal vascular permeability. In the pathological condition, the KCs elimination rescues Con A-induced acute hepatitis through suppressing proinflammatory immune responses by down-regulation of hepatitis-associated cytokines/chemokines in serum such as CXCL10, and recruitment of infiltrating immune cells (monocytes, T, B, and NK cells). We further documented that deficiency or blockade of CXCL10 attenuated the development of Con A-induced hepatitis associated with reduction of the infiltrating monocytes, especially inflammatory Ly6C^hi monocytes.

Conclusions: This study supports the notion that KCs actively interact with immune cells and LSECs for maintaining immune response and liver homeostasis. Our data indicate that the interplay between KCs and infiltrated monocytes via CXCL10 contribute to Con A-induced hepatitis.

Tumor circulome in the liquid biopsies for cancer diagnosis and prognosis

Liquid biopsy is a convenient, fast, non-invasive and reproducible sampling method that can dynamically reflect the changes in tumor gene expression profile, and provide a robust basis for individualized therapy and early diagnosis of cancer. Circulating tumor DNA (ctDNA) and circulating tumor cells (CTCs) are the currently approved diagnostic biomarkers for screening cancer patients. In addition, tumor-derived extracellular vesicles (tdEVs), circulating tumor-derived proteins, circulating tumor RNA (ctRNA) and tumor-bearing platelets (TEPs) are other components of liquid biopsies with diagnostic potential. In this review, we have discussed the clinical applications of these biomarkers, and the factors that limit their implementation in routine clinical practice. In addition, the most recent developments in the isolation and analysis of circulating tumor biomarkers have been summarized, and the potential of non-blood liquid biopsies in tumor diagnostics has also been discussed.

Tumor cell-derived exosomes home to their cells of origin and can be used as Trojan horses to deliver cancer drugs

Cancer is the second leading cause of death worldwide and patients are in urgent need of therapies that can effectively target cancer with minimal off-target side effects. Exosomes are extracellular nano-shuttles that facilitate intercellular communication between cells and organs. It has been established that tumor-derived exosomes contain a similar protein and lipid composition to that of the cells that secrete them, indicating that exosomes might be uniquely employed as carriers for anti-cancer therapeutics. Methods: We isolated exosomes from two cancer cell lines, then co-cultured each type of cancer cells with these two kinds of exosomes and quantified exosome. HT1080 or Hela exosomes were systemically injected to Nude mice bearing a subcutaneous HT1080 tumor to investigate their cancer-homing behavior. Moreover, cancer cell-derived exosomes were engineered to carry Doxil (a common chemotherapy drug), known as D-exo, were used to detect their target and therapeutic efficacy as anti-cancer drugs. Exosome proteome array analysis were used to reveal the mechanism underly this phenomenon. Results: Exosomes derived from cancer cells fuse preferentially with their parent cancer cells, in vitro. Systemically injected tumor-derived exosomes home to their original tumor tissues. Moreover, compared to Doxil alone, the drug-loaded exosomes showed enhanced therapeutic retention in tumor tissues and eradicated them more effectively in nude mice. Exosome proteome array analysis revealed distinct integrin expression patterns, which might shed light on the underlying mechanisms that explain the exosomal cancer-homing behavior. Conclusion: Here we demonstrate that the exosomes' ability to target the parent cancer is a phenomenon that opens up new ways to devise targeted therapies to deliver anti-tumor drugs.

Mononuclear phagocyte system blockade improves therapeutic exosome delivery to the myocardium

Rationale: Exosomes are emerging as a promising drug delivery carrier. However, rapid uptake of exosomes by the mononuclear phagocyte system (MPS) remains an obstacle for drug delivery into other targeted organs, including the heart. We hypothesized that prior blocking of uptake of exosomes by the MPS would improve their delivery to the targeted organs.

Methods: Exosomes were isolated from the cell culture medium. Fluorescence-labeled exosomes were tracked in vitro and in vivo by fluorescence imaging. The expression of clathrin heavy chain (Cltc), cavolin1, Pak1 and Rhoa, known genes for endocytosis, were profiled in various cell lines and organs by qPCR. The knockdown efficiency of siRNA against Cltc was analyzed by Western blotting. Exosome^control and exosome^blocking were constructed by encapsulating isolated exosomes with siControl or siClathrin via electroporation, while exosome^therapeutic was constructed by encapsulating isolated exosomes with miR-21a. Doxorubicin-induced cardiotoxicity model was used to verify the therapeutic efficiency of the exosome-based miR-21a delivery by echocardiography.

Results: Exosomes were preferentially accumulated in the liver and spleen, mainly due to the presence of abundant macrophages. Besides the well-known phagocytic effect, efficient endocytosis also contributes to the uptake of exosomes by macrophages. Cltc was found to be highly expressed in the macrophages compared with other endocytosis-associated genes. Accordingly, knockdown of Cltc significantly decreased the uptake of exosomes by macrophages in vitro and in vivo. Moreover, prior injection of exosome^blocking strikingly improved the delivery efficiency of exosomes to organs other than spleen and liver. Consistently, compared with the direct injection of exosome^therapeutic, prior injection of exosome^blocking produced a much better therapeutic effect on cardiac function in the doxorubicin-induced cardiotoxicity mouse model.

Conclusions: Prior blocking of endocytosis of exosomes by macrophages with exosome^blocking successfully and efficiently improves the distribution of following exosome^therapeutic in targeted organs, like the heart. The established two-step exosome delivery strategy (blocking the uptake of exosomes first followed by delivery of therapeutic exosomes) would be a promising method for gene therapy.