Exosomes Derived From Natural Killer Cells Exert Therapeutic Effect in Melanoma

Porcine GM-CSF and APS as a novel complex immunostimulant improves the immune effect of pseudorabies inactivated vaccine

Currently, pseudorabies (PR) is mainly controlled with attenuated and inactivated vaccines. In the case of inactivated vaccines, immunostimulants play a crucial role in triggering the host immune response. In this study, granulocyte-macrophage colony-stimulating factor (GM-CSF) and astragalus polysaccharide (APS) were investigated as a novel complex immunostimulant in inactivated PR vaccine. The findings indicated that neither porcine GM-CSF (pGM-CSF) nor APS exhibited any cytotoxic effect on cells. In addition, the PR vaccine+pGM-CSF+APS group exhibited higher levels of PRV-specific gB and neutralizing antibodies. Moreover, the group treated with pGM-CSF+APS immunostimulants demonstrated a notable increase in the production of IL-4, IL-10, IL-2, IFN-γ. After PRV challenge, the PR vaccine with pGM-CSF and APS alleviated clinical symptoms and reduced mortality. Additionally, the complex immunostimulant group showed a lower viral DNA copy number in various tissues compared to the PR vaccine alone group, as well as the groups treated with PR vaccine+pGM-CSF and PR vaccine+APS. Moreover, mice challenged with PRV in the PR Vaccine+pGM-CSF+APS group reduced substantial tissue lesions than other groups. These results demonstrate the potential of pGM-CSF and APS when used together as complex immunostimulant to enhance both humoral and cellular immune responses to inactivated vaccines, providing novel perspectives for the further development of immunostimulants.

Engineered NK Exosomes Captured Antigens In Situ for Enhanced Tumor Immunotherapy

Natural killer (NK) cells are widely involved in the field of tumor immunotherapy due to their unique killing ability. However, the durability and efficacy of NK-cell monotherapy are facing great challenges owing to the limitation of immunosuppressive tumor microenvironment (TME). NK cell-derived exosomes (Neo) not only play an innate immunomodulatory role similar to NK cells but also emerge as promising antitumor nanocarriers. In this study, an engineered Neo (R@Neo-MN) was designed that encapsulates the multifunctional antitumor drug (Raddeanin a, RA) and modified with maleimide (Mal, M) and mannose (Man, N). The obtained R@Neo-MN could not only exert NK cell-like antitumor function but also induce the immunogenic cell death of tumors to release tumor-associated antigens (TAAs). Furthermore, R@Neo-MN activated the cyclic guanosine monophosphate-adenosine monophosphate synthase/interferon gene stimulator (cGAS/STING) to release type I interferons (IFN). Then, R@Neo-MN could capture TAAs through Mal and specifically target dendritic cells (DCs) through Man, thereby promoting the maturation of DCs and enhancing tumor-specific cytotoxic T-cell (CTL)-mediated adaptive immunity. The released IFN further promoted the infiltration and activition of NK cells and CTLs at the tumor site. Our study suggested a novel strategy that harnesses both innate and adaptive immunity for enhanced tumor immunotherapy.

Exosomes as key mediators in immune and cancer cell interactions: insights in melanoma progression and therapy

Exosomes (30-150 nm) are small extracellular vesicles that are secreted by cells into the extracellular environment and are known to mediate cell-to-cell communication. Exosomes contain proteins, lipids, and RNA molecules in relative abundance, capable of modifying the activity of target cells. Melanoma-derived exosomes (MEXs) promote the transfer of oncogenic signals and immunosuppressive factors into immune cells, resulting in a bias of the immune response towards tumor-promoting processes. MEXs could suppress the activation and proliferation of T cells and dendritic cells and induce differentiation of myeloid-derived suppressor cells (MDSCs) and regulatory T cells (Tregs). They can induce apoptosis of antigen-specific CD8 + T cells and promote the transfer of tumor antigens, resulting in immune evasion. Specifically, MEXs can shuttle cytokines like interleukin-10 (IL-10) and transforming growth factor-β (TGF-β) to immune cells or express programmed death-ligand 1 (PD-L1 or CD274), creating an immune-suppressive microenvironment that promotes tumorigenesis. Since exosomes preferentially accumulate in melanoma tissues, this targeted delivery could enhance the bioavailability of treatments while limiting side effects. Here, we review the molecular composition of melanoma-derived exosomes, their mechanisms of action, and their potential as therapeutic targets or biomarkers in melanoma. The summarizations of these mechanisms to appropriately influence exosome-mediated interactions could yield new tactics to elicit anti-melanoma immunity or augment the therapeutic effects of current therapies.

Iron-Cobalt Alloy@Graphene-Engineered Milk Extracellular Vesicles for Gastric Retentive Drug Delivery

Oral drug delivery is widely used for treating gastric diseases as it allows drugs to act directly on gastric lesions, thereby improving therapeutic outcomes. However, its efficacy is hindered by the specific gastric environment, such as the gastric mucosal barrier, which limits drug penetration, and the short gastric emptying time, which results in transient residence time. Raw milk-derived extracellular vesicles (M-EVs) offer promise as a gastric drug delivery platform. Their high cellular affinity, stability under gastrointestinal conditions, and ability to protect drugs from acidic and enzymatic degradation make them suitable for this purpose. Incorporating mangetic nanoparticles encapsulated in M-EV provides magnetic navigation and active mucosal penetration capabilities. Herein, we developed a gastric drug delivery system based on iron-cobalt alloy@graphene (FeCo@G)-engineered M-EV (M-FNP). M-FNP serves as a versatile drug carrier that can load both small molecules and proteins through simple physical approach. And it demonstrates stability in the simulated gastric fluid system for at least 6 hours. Under magnetic field guidance, it penetrates the simulated mucosal layer and is internalized by cells within 4 hours significantly enhancing cellular drug uptake. M-FNP is expected to serve as an innovative drug delivery platform with enhanced retention capabilities within the stomach.

Secretory exosomes from modified immune cells against cancer

Extracellular vesicles (EVs) play significant roles in cancer progression through mediating inter/intra cellular communications within tumor microenvironment (TME). EVs are used as non-invasive diagnostic tools, drug delivery systems, and cancer vaccines, considering the anti-tumor potential, safety, biocompatibility and physiochemical stability of endogenous EVs. Modification of immune cells, either genetically or epigenetically, is a growing field of cancer research with the goal of enhancing efficacy of immunotherapy. This review focuses on the possibility of manipulating immune cells including dendritic cells (DCs), natural killer (NK) cells and T cells to secrete EVs that exert immune function either by activating immune responses or altering immune cell behavior to enhance anti-tumor efficacy, and discusses potential obstacles and recommendations for improved functionality of this therapeutic method.

Oxaliplatin-loaded natural killer cell-derived exosomes for a safe and efficient chemoimmunotherapy of colorectal cancer

In recent years, the limited biocompatibility and serious side effects of oxaliplatin (L-OHP) have restricted its clinical application. Exosomes are biologically active vesicles with a double membrane structure secreted by almost all living cells. They transport biomolecules (e.g., cytokines, proteins, neurotransmitters, and lipids) used for inter-cellular regulation and communication to target cells. Because of their excellent bio-compatibility, highly permeable and low-toxicity properties, exosomes are receiving widespread attention and importance as a drug delivery platform. In this study, we demonstrated the successful isolation of saucer-like Natural Killer cell exosomes (NK-Exosomes, NK-Exos) from NK cell cultures by density gradient centrifugation. The nano-drug delivery system (L-OHP-Exos) was successfully prepared using sonication. This nanomedicine delivery system based on exosomes effectively delivers chemotherapy drugs into tumor cells, inhibiting their growth. Moreover, it enhances the generation of reactive oxygen species (ROS) within tumor cells through the synergistic action of its Fas ligand (FasL) and oxaliplatin, subsequently inducing apoptosis. Following a series of rigorous in vivo experimental validations, we further confirmed the dual benefits of NK-Exos: their inherent growth inhibitory effects on tumors and their ability to markedly potentiate the antineoplastic activity of L-OHP in colorectal cancer therapy. Due to the limited solubility of oxaliplatin in phospholipid bilayers, encapsulation of oxaliplatin within L-OHP-Exos minimizes its binding to plasma proteins post-intravenous administration, thereby augmenting the sustained release and bioavailability of the drug. This nano-drug delivery system offers a novel approach for the treatment of colorectal cancer and holds promising potential for clinical application.

The potential mechanisms of extracellular vesicles in transfusion-related adverse reactions: Recent advances

Blood transfusion is an irreplaceable clinical treatment. Blood components are differentiated and stored according to specific guidelines. Storage temperatures and times vary depending on the blood component, but they all release extracellular vesicles (EVs) during storage. Although blood transfusions can be life-saving, they can also cause many adverse transfusion reactions, among which the effects of EVs are of increasing interest to researchers. EVs are submicron particles that vary in size, composition, and surface biomarkers, are encapsulated by a lipid bilayer, and are not capable of self-replication. EVs released by blood cells are important contributors to pathophysiologic states through proinflammatory, coagulant, and immunosuppressive effects, which in turn promote or inhibit the associated disease phenotype. Therefore, this review explores the potential mechanisms of hematopoietic-derived EVs in transfusion-associated adverse reactions and discusses the potential of the latest proteomics tools to be applied to the analysis of EVs in the field of transfusion medicine with a view to reducing the risk of blood transfusion.

Extracellular vesicles and the tumour microenvironment

Extracellular vesicles (EVs), tiny packages of information released by cells, are well established as being involved in unwanted cell-to-cell communication in cancer. EVs from cancer cells have been associated with the spread of drug resistance, immune suppression, and metastasis. Additional to cancer cells, the tumour microenvironment (TME) involves many cell types -including immune cells, fibroblasts, and endothelial cells, each of which has a potential role in how tumours grow, spread, and respond (or otherwise) to therapy. This review collates and distils research developments regarding the role of EVs in multi-way communication between cells in the TME. Further research including tailored clinical studies are now warranted to determine how best to prevent this extensive adverse communication occurring and/or how best to exploit it for biomarker discovery and as a therapeutic approach, in the interest of patients and also for economic benefit.

Machine Learning-enhanced Signature of Metastasis-related T Cell Marker Genes for Predicting Overall Survival in Malignant Melanoma

In this study, we aimed to investigate disparities in the tumor immune microenvironment (TME) between primary and metastatic malignant melanoma (MM) using single-cell RNA sequencing (scRNA- seq ) and to identify metastasis-related T cell marker genes (MRTMGs) for predicting patient survival using machine learning techniques. We identified 6 distinct T cell clusters in 10×scRNA-seq data utilizing the Uniform Manifold Approximation and Projection (UMAP) algorithm. Four machine learning algorithms highlighted SRGN, PMEL, GPR143, EIF4A2, and DSP as pivotal MRTMGs, forming the foundation of the MRTMGs signature. A high MRTMGs signature was found to be correlated with poorer overall survival (OS) and suppression of antitumor immunity in MM patients. We developed a nomogram that combines the MRTMGs signature with the T stage and N stage, which accurately predicts 1-year, 3-year, and 5-year OS probabilities. Furthermore, in an immunotherapy cohort, a high MRTMG signature was associated with an unfavorable response to anti-programmed death 1 (PD-1) therapy. In conclusion, primary and metastatic MM display distinct TME landscapes with different T cell subsets playing crucial roles in metastasis. The MRTMGs signature, established through machine learning, holds potential as a valuable biomarker for predicting the survival of MM patients and their response to anti-PD-1 therapy.

Killing the killers: Natural killer cell therapy targeting glioma stem cells in high-grade glioma

High-grade gliomas (HGGs), including glioblastoma (GBM) in adults and diffuse intrinsic pontine glioma (DIPG) in children, are among the most aggressive and deadly brain tumors. A key factor in their resilience is the presence of glioma stem cells (GSCs), which drive tumor initiation, progression, and resistance to treatment. Targeting and eradicating GSCs holds potential for curing both GBM and DIPG. Natural killer (NK) cells, as part of the innate immune system, naturally recognize and destroy malignant cells. Recent advances in NK cell-based therapies, such as chimeric antigen receptor (CAR)-NK cells, NK cell engagers, and NK cell-derived exosomes, offer promising approaches for treating GBM and DIPG, particularly by addressing the persistence of GSCs. This review highlights these advancements, explores challenges such as the blood-brain barrier and the immunosuppressive tumor microenvironment, and proposes future directions for improving and clinically advancing these NK cell-based therapies for HGGs.

Harnessing Lactobacillus reuteri-Derived Extracellular Vesicles for Multifaceted Cancer Treatment

Extracellular vesicles (EVs) have emerged as valuable biological materials for treating intractable diseases. Extensive studies are conducted on EVs derived from various cellular sources. In this study, EVs derived from Lactobacillus reuteri (L. reuteri), a probiotic, exhibit remarkable cancer therapeutic efficacy when administered orally is reported. These L. reuteri-derived EVs (REVs) demonstrate stability in the gastrointestinal tract and exert significant anti-tumor effects. Using A549 cells and murine models, we confirmed that REVs mediate their therapeutic effects by modulating apoptotic signaling pathways. Furthermore, the combination of REV with drugs enhances tumor ablation and induces immunogenic cell death. In a mouse model, oral administration of REVs encapsulating indocyanine green followed by photothermal therapy led to complete tumor elimination within 32 days. REVs represent a promising biological therapeutic platform for cancer treatment, either independently or in combination with other therapies, depending on the treatment objectives.

Enhanced Anti-Tumor Effects of Natural Killer Cell-Derived Exosomes Through Doxorubicin Delivery to Hepatocellular Carcinoma Cells: Cytotoxicity and Apoptosis Study

Exosomes are nanosized extracellular vesicles secreted by various cells, including natural killer (NK) cells, and are known for their low toxicity, high permeability, biocompatibility, and strong targeting ability. NK cell-derived exosomes (NK-exos) contain cytotoxic proteins that enhance tumor-targeting efficiency, making them suitable for treating solid tumors such as hepatocellular carcinoma (HCC). Despite their potential in drug delivery, the mechanisms of drug-loaded NK-exos, particularly those loaded with doxorubicin (NK-exos-Dox), remain unclear in HCC. This study explored the anti-tumor effects of NK-exos-Dox against Hep3B cells in vitro. NK-exos-Dox expressed exosome markers (CD9 and CD63) and cytotoxic proteins (granzyme B and perforin) and measured 170-220 nm in size. Compared to NK-exos, NK-exos-Dox enhanced cytotoxicity and apoptosis in Hep3B cells by upregulating pro-apoptotic proteins (Bax, cytochrome c, cleaved caspase 3, and cleaved PARP) and inhibiting the anti-apoptotic protein (Bcl-2). These findings suggest that NK-exos-Dox significantly boost anti-tumor effects by activating specific cytotoxic molecules, offering promising therapeutic opportunities for solid tumor treatment, including HCC.

Exosomes: a double-edged sword in cancer immunotherapy

Over the past few decades, immunotherapy has emerged as a powerful strategy to overcome the limitations of conventional cancer treatments. The use of extracellular vesicles, particularly exosomes, which carry cargoes capable of modulating the immune response, has been extensively explored as a potential therapeutic approach in cancer immunotherapy. Exosomes can deliver their cargo to target cells, thereby influencing their phenotype and immunomodulatory functions. They exhibit either immunosuppressive or immune-activating characteristics, depending on their internal contents. These exosomes originate from diverse cell sources, and their internal contents can vary, suggesting that there may be a delicate balance between immune suppression and stimulation when utilizing them for immunotherapy. Therefore, a thorough understanding of the molecular mechanisms underlying the role of exosomes in cancer progression is essential. This review focuses on the molecular mechanisms driving exosome function and their impact on the tumor microenvironment (TME), highlighting the intricate balance between immune suppression and activation that must be navigated in exosome-based therapies. Additionally, it underscores the challenges and ongoing efforts to optimize exosome-based immunotherapies, thereby making a significant contribution to the advancement of cancer immunotherapy research.

Natural Killer Cell-Derived Exosome Mimetics as Natural Nanocarriers for In Vitro Delivery of Chemotherapeutics to Thyroid Cancer Cells

BACKGROUND

Exosomes have become a potential field of nanotechnology for the treatment and identification of many disorders. However, the generation of exosomes is a difficult, time-consuming, and low-yielding procedure. At the same time, exosome mimetics (EM) resemble exosomes in their characteristics but have higher production yields. The aim of this study was to produce natural killer (NK) cell-derived EM (NKEM) loaded with sorafenib and test their killing ability against thyroid cancer cell lines.

MATERIALS AND METHODS

Sorafenib was loaded into NKEM by mixing sorafenib with NK cells during NKEM production (NKEM-S). Then, these two types of nanoparticles were characterized with nanoparticle tracking analysis (NTA) to measure their sizes. In addition, the cellular uptake and in vitro killing effect of NKEM-S on thyroid cancer cell lines were investigated using confocal laser microscopy and bioluminescence imaging (BLI) techniques.

RESULTS

The uptake of NKEM and NKEM-S by the thyroid cancer cells was observed. Moreover, BLI confirmed the killing and anti-proliferation effect of NKEM-S on two thyroid cancer cell lines. Especially important, the NKEM-S demonstrated a desirable killing effect even for anaplastic thyroid cancer (ATC) cells.

CONCLUSION

Sorafenib-loaded NKEM showed the ability to kill thyroid cancer cells in vitro, even against ATC. This provides a new opportunity for drug delivery systems and thyroid cancer treatment.

Extracellular vesicles-based vaccines: Emerging immunotherapies against cancer

Cancer vaccines are promising therapeutic approaches to enhance specific T-cell immunity against most solid tumors. By stimulating anti-tumor immunity, clearing minimal residual disease, and minimizing adverse effects, these vaccines target tumor cells and are effective when combined with immune checkpoint blockade or other immunotherapies. However, the development of tumor cell-based vaccines faces quality issues due to poor immunogenicity, tumor heterogeneity, a suppressive tumor immune microenvironment, and ineffective delivery methods. In contrast, extracellular vesicles (EVs), naturally released by cells, are considered the ideal drug carriers and vaccine platforms. EVs offer highly organ-specific targeting, induce broader and more effective immune responses, and demonstrate superior tissue delivery ability. The development of EV vaccines is crucial for advancing cancer immunotherapy. Compared to cell-based vaccines, EV vaccines produced under Good Manufacturing Practices (GMP) offer advantages such as high safety, ease of preservation and transport, and a wide range of sources. This review summarizes the latest research findings on EV vaccine and potential applications in this field. It also highlights novel neoantigens for the development of EV vaccines against cancer.

Photosensitive Hybrid γδ-T Exosomes for Targeted Cancer Photoimmunotherapy

Melanoma is the most aggressive type of skin cancers. Traditional chemotherapy and radiotherapy have limited effectiveness and can lead to systemic side effects. Photodynamic therapy (PDT) is a photoresponsive cancer therapy based on photosensitizers to generate reactive oxygen species (ROS) to eradicate tumor cells. Our previous study showed that exosomes derived from human γδ-T cells (γδ-T exosomes) could control Epstein-Barr virus-associated tumors. Here, we combined γδ-T exosomes and PDT for targeted photoimmunotherapy by membrane fusion of γδ-T exosomes and Chlorin e6 (Ce6)-loaded liposomes. The functional surface proteins, such as CCR5 and PD-1, on the hybrid exosomes mediated the specific binding of hybrid exosomes toward melanoma tissues. The cytolytic molecules, such as granzyme A, granzyme B, perforin, and granulysin from γδ-T exosomes, induced specific apoptosis of cancer cells without harming normal cells. In response to light irradiation, ROS generation inside melanoma cells synergized with cytolytic molecules to induce apoptosis and promote immunogenic cancer cell death (ICD). The subsequently released damage-associated molecular patterns (DAMPs) could stimulate human dendritic cell maturation and induce melanoma antigen-specific CD4+ and CD8+ T-cell responses, thereby enhancing antitumor immunity. This study provides a promising strategy by combining γδ-T exosomes and PDT for photoimmunotherapy, thereby expanding the clinical applications of γδ-T exosome therapy for cancer patients.

Engineered extracellular vesicles with DR5 agonistic scFvs simultaneously target tumor and immunosuppressive stromal cells

Small extracellular vesicles (sEVs) are nanosized vesicles. Death receptor 5 (DR5) mediates extrinsic apoptosis. We engineer DR5 agonistic single-chain variable fragment (scFv) expression on the surface of sEVs derived from natural killer cells. PDGFR transmembrane domain delivers DR5-scFvs to the surface of sEVs. DR5-scFv sEVs rapidly induce apoptosis of different types of DR5+ cancer cells, myeloid-derived suppressor cells (MDSCs), and cancer-associated fibroblasts (CAFs). DR5-scFv sEVs migrate specifically to DR5+ tumors in vitro and in vivo. Systemic delivery of DR5-scFv sEVs significantly inhibits the growth of DR5+ melanoma, liver cancer, and breast cancer and prolongs mouse life span without significant toxicity. DR5-scFv sEVs are significantly more efficacious than DR5 antibodies in vivo. In organotypic patient-derived melanoma slice cultures, DR5-scFv sEVs effectively inhibit melanoma cells and MDSCs and activate CD8+ T cells. Our studies demonstrate that DR5-scFv sEVs can inhibit tumor growth by targeting tumor cells and immunosuppressive stromal cells in the TME.

Iron Knights with Nanosword Induced Ferroptosis in the Battle Against Oral Carcinoma

Oral squamous cell carcinoma (OSCC) is a tumor characterized by cellular redox imbalance, rendering it particularly sensitive to ferroptosis treatment. However, traditional ferroptosis inducers have a few drawbacks. In this study, ultrasmall AuMn nanoclusters (AMNCs) with a bovine serum albumin (BSA) ligand were synthesized and encapsulated in natural killer (NK) cell-derived exosomes to form an Exo-AMNCs composite for targeted ferroptosis therapy of OSCC. Unlike previously reported alloyed metal nanoclusters, not only do AMNCs react with intracellular H2O2 to produce reactive oxygen species (ROS) and induce ferroptosis but also the BSA ligand improves biocompatibility and water solubility. These properties render AMNCs ideal for fluorescence imaging in vivo. When combined with NK cell exosomes, the Exo-AMNCs composite exhibited strong targeted imaging and therapeutic effects on OSCC. Further investigation into the mechanistic details demonstrated that Exo-AMNCs downregulate the overexpression of fat mass and obesity-associated (FTO) in OSCC and regulate the key ferroptosis-related protein glutathione peroxidase 4 (GPX4).

NK cell-derived exosomes inhibit survival of Mycobacterium tuberculosis by promoting apoptosis in mice

AIM

To investigate anti-Mycobacterium tuberculosis (Mtb) influences exerted by natural killer cell-derived exosomes (NK-exo) on mice and to elucidate underlying immunologic mechanisms.

METHODS

We established tuberculosis (TB) model in mouse by injecting Mtb H37Ra (1 × 106 colony counting (CFU), i.v.) into tail vein for 14 days. The survival rate of Mtb was assessed through CFU, apoptosis rates were measured utilizing flow cytometry, and inflammation relief was quantified via HE staining. Expressions of apoptosis, inflammation, and pyroptosis-related proteins were quantified by Western blotting and RT-qPCR. ELISA was utilized for detecting inflammatory cytokines production. Intracellular reactive oxygen species (ROS) levels were assessed through DCFH-DA fluorescent probe assay.

RESULTS

NK-exo treatment reduced Mtb load in lung and spleen tissues and alleviated inflammation in mice lung tissues. NK-exo intervention increased protein levels of markers associated with apoptosis, PARP and caspase-3/8/9, downregulating the concentrations of pro-inflammatory cytokines, comprising IL-1β, TNF-α, IL-6, along with protein expressions of biomarkers, ASC, NLRP3, GSDMD, associated to inflammation and pyroptosis. NK-exo also elevated ROS levels without affecting lactate dehydrogenase (LDH) release from macrophages.

CONCLUSION

NK-exo exhibits anti-tuberculosis activity in experimental TB mice. The underlying mechanism involve regulating caspase-dependent apoptotic signaling pathway to promote cell apoptosis, as well as modulating NLRP3 signaling pathway to suppress the inflammatory response.

Exosome may be the next generation of promising cell-free vaccines

Traditional vaccines have limits against some persistent infections and pathogens. The development of novel vaccine technologies is particularly critical for the future. Exosomes play an important role in physiological and pathological processes. Exosomes present many advantages, such as inherent capacity being biocompatible, non-toxic, which make them a more desirable candidate for vaccines. However, research on exosomes are in their infancy and the barriers of low yield, low purity, and weak targeting of exosomes limit their applications in vaccines. Accordingly, further exploration is necessary to improve these problems and subsequently facilitate the functional studies of exosomes. In this study, we reviewed the origin, classification, functions, modifications, separation and purification, and characterization methods of exosomes. Meanwhile, we focused on the role and mechanism of exosomes for cancer and COVID-19 vaccines.

Extracellular Vesicles and Their Applications in Tumor Diagnostics and Immunotherapy

Extracellular vesicles (EVs) are cell-derived nanoparticles that have attracted significant attention in the investigation of human health and disease, including cancer biology and its clinical management. Concerning cancer, EVs have been shown to influence numerous aspects of oncogenesis, including tumor proliferation and metastasis. EVs can augment the immune system and have been implicated in virtually all aspects of innate and adaptive immunity. With immunotherapy changing the landscape of cancer treatment across multiple disease sites, it is paramount to understand their mechanisms of action and to further improve upon their efficacy. Despite a rapidly growing body of evidence supporting of the utility of EVs in cancer diagnostics and therapeutics, their application in clinical trials involving solid tumors and immunotherapy remains limited. To date, relatively few trials are known to incorporate EVs in this context, mainly employing them as biomarkers. To help address this gap, this review summarizes known applications of EVs in clinical trials and provides a brief overview of the roles that EVs play in cancer biology, immunology, and their proposed implications in immunotherapy. The impetus to leverage EVs in future clinical trials and correlative studies is crucial, as they are ideally positioned to synergize with advancements in multi-omics research to further therapeutic discovery and our understanding of cancer biology.

Advances in macrophage-derived exosomes as immunomodulators in disease progression and therapy

Most somatic cells secrete vesicles called exosomes, which contain a variety of biomolecules. Recent research indicates that macrophage-derived exosomes are strongly correlated with tumors, infectious diseases, chronic inflammation, and tissue fibrosis. Therefore, the purpose of this review is to delve into the mechanisms of pathological states and how macrophage-derived exosomes react to them. We also discuss the biological effects of exosomes and how they affect disease. In addition, we have examined the possible uses of exosomes in illness treatment, highlighting both the benefits and drawbacks of these applications.

Homotypic cell membrane-camouflaged biomimetic PLGA nanoparticle loading triptolide for the treatment of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the fourth leading cause of cancer-associated death worldwide. Beside early detection, early diagnosis, and early surgery, it is urgent to try new strategies for the treatment of HCC. Triptolide (TPL) has been employed to treat HCC. However, its clinical applications were restricted by the narrow therapeutic window, severe toxicity, and poor water-solubility. In this study, we developed cancer cell membrane-camouflaged biomimetic PLGA nanoparticles loading TPL (TPL@mPLGA) with the homologous targeting property for the treatment of HCC. The TPL@mPLGA was successfully prepared with particle size of 195.5 ± 7.5 nm and zeta potential at -21.5 ± 0.2 mV with good stability. The drug loading (DL) of TPL@mPLGA was 2.94%. After Huh-7 cell membrane coating, the natural Huh-7 cell membrane proteins were found to be retained on TPL@mPLGA, thus endowing the TPL@mPLGA with enhanced accumulation at tumor site, and better anti-tumor activity in vitro and in vivo when compared with TPL or TPL@PLGA. The TPL@mPLGA showed enhanced anti-tumor effects and reduced toxicity of TPL, which could be adopted for the treatment of HCC.

Cell-based glycoengineering of extracellular vesicles through precise genome editing

Engineering of extracellular vesicles (EVs) towards more efficient targeting and uptake to specific cells has large potentials for their application as therapeutics. Carbohydrates play key roles in various biological interactions and are essential for EV biology. The extent to which glycan modification of EVs can be achieved through genetic glycoengineering of their parental cells has not been explored yet. Here we introduce targeted glycan modification of EVs through cell-based glycoengineering via modification of various enzymes in the glycosylation machinery. In a "simple cell" strategy, we modified major glycosylation pathways by knocking-out (KO) essential genes for N-glycosylation (MGAT1), O-GalNAc glycosylation (C1GALT1C1), glycosphingolipids (B4GALT5/6), glycosaminoglycans (B4GALT7) and sialylation (GNE) involved in the elongation or biosynthesis of the glycans in HEK293F cells. The gene editing led to corresponding glycan changes on the cells as demonstrated by differential lectin staining. Small EVs (sEVs) isolated from the cells showed overall corresponding glycan changes, but also some unexpected differences to their parental cell including enrichment preference for certain glycan structures and absence of other glycan types. The genetic glycoengineering did not significantly impact sEVs production, size distribution, or syntenin-1 biomarker expression, while a clonal influence on sEVs production yields was observed. Our findings demonstrate the successful implementation of sEVs glycoengineering via genetic modification of the parental cell and a stable source for generation of glycoengineered sEVs. The utilization of glycoengineered sEVs offers a promising opportunity to study the role of glycosylation in EV biology, as well as to facilitate the optimization of sEVs for therapeutic purposes.

Exosome-mediated Transfer of lncRNA in Liver Associated Diseases; Uncovered Truths

Exosomes are extracellular vesicles with a diameter ranging from 40 to 160 nm. They are produced by hepatocytes, cholangiocytes, hepatic stellate cells (HSCs), liver sinusoidal endothelial cells (LSECs) and Kupffer cells in liver tissue. The secretion of exosomes might vary in quantity and composition in reaction to multiple triggers and various stages of disease. They transport various payloads, such as proteins, DNAs, and RNAs, and enable cell interaction to regulate myriad physiological and pathological processes in liver tissue. Long non-coding RNAs (lncRNAs) are a crucial component of exosomes with an excellent capability to regulate multiple cellular activities such as differentiation, development, metabolism, proliferation, apoptosis, and activation. With the advancements in transcriptomic and genomic study methods and database management technology, the functions and mechanisms of exosomal lncRNAs in liver diseases have been well-studied. This article delves into the detailed role of exosomal lncRNAs in liver disease onset and progression, ranging from hepatocellular carcinoma (HCC) to liver fibrosis drug-induced liver damage (DILI) and steatotic liver diseases.

Immune Cell-Derived Exosomes: A Cell-Free Cutting-Edge Tumor Immunotherapy

Extracellular vesicles (EVs) are cellular communication molecules and are classified into three major subpopulations, such as microvesicles, apoptotic bodies, and exosomes. Among these, exosomes-based cancer research is a cutting-edge investigation approach to cancer understanding. During cancer progression , tumor-derived exosomes can reprogram the cellular system and promote cancer. Circulating exosomes in the body fluids such as blood, plasma, serum, saliva, CSF, sweat, and tears play a key role in identifying diagnostic and prognostic cancer biomarkers. Diverse therapeutic sources of exosomes including stem cells, plants, and immune cells, etc. exhibit significant cancer-healing properties. Although cancer-targeting immunotherapy is an effective strategy, it has limitations such as toxicity, and high costs. In comparison, immune cell-derived exosomes-based immunotherapy is a cell-free approach for cancer treatment and has advantages like less toxicity, biocompatibility, reduced immunogenicity, and efficient, target-specific cancer therapeutic development. This review highlights the therapeutic signature of immune cell-derived exosomes for cancer treatment.

The roles of cancer stem cells and therapeutic implications in melanoma

Melanoma is a highly malignant skin tumor characterized by high metastasis and poor prognosis. Recent studies have highlighted the pivotal role of melanoma stem cells (MSCs)-a subpopulation of cancer stem cells (CSCs)-in driving tumor growth, metastasis, therapeutic resistance, and recurrence. Similar to CSCs in other cancers, MSCs possess unique characteristics, including specific surface markers, dysregulated signaling pathways, and the ability to thrive within complex tumor microenvironment (TME). This review explored the current landscape of MSC research, discussing the identification of MSC-specific surface markers, the role of key signaling pathways such as Wnt/β-catenin, Notch, and Hedgehog (Hh), and how interactions within the TME, including hypoxia and immune cells, contribute to MSC-mediated drug resistance and metastatic behavior. Furthermore, we also investigated the latest therapeutic strategies targeting MSCs, such as small-molecule inhibitors, immune-based approaches, and novel vaccine developments, with an emphasis on their potential to overcome melanoma progression and improve clinical outcomes. This review aims to provide valuable insights into the complex roles of MSCs in melanoma biology and offers perspectives for future research and therapeutic advances against this challenging disease.

MicroRNA-enriched exosome as dazzling dancer between cancer and immune cells

Exosomes are widely recognized for their roles in numerous biological processes and as intercellular communication mediators. Human cancerous and normal cells can both produce massive amounts of exosomes. They are extensively dispersed in tumor-modeling animals' pleural effusions, ascites, and plasma from people with cancer. Tumor cells interact with host cells by releasing exosomes, which allow them to interchange various biological components. Tumor growth, invasion, metastasis, and even tumorigenesis can all be facilitated by this delicate and complex system by modifying the nearby and remote surroundings. Due to the existence of significant levels of biomolecules like microRNA, exosomes can modulate the immune system's stimulation or repression, which in turn controls tumor growth. However, the role of microRNA in exosome-mediated communication between immunological and cancer cells is still poorly understood. This study aims to get the most recent information on the "yin and yang" of exosomal microRNA in the regulation of tumor immunity and immunotherapy, which will aid current cancer treatment and diagnostic techniques.

Exosome-based immunotherapy as an innovative therapeutic approach in melanoma

The malignant form of melanoma is one of the deadliest human cancers that accounts for almost all of the skin tumor-related fatalities in its later stages. Achieving an exhaustive understanding of reliable cancer-specific markers and molecular pathways can provide numerous practical techniques and direct the way toward the development of rational curative medicines to increase the lifespan of patients. Immunotherapy has significantly enhanced the treatment of metastatic and late-stage melanoma, resulting in an incredible increase in positive responses to therapy. Despite the increasing occurrence of melanoma, the median survival rate for patients with advanced, inoperable terminal disease has increased from around six months to almost six years. The current knowledge of the tumor microenvironment (TME) and its interaction with the immune system has resulted in the swift growth of innovative immunotherapy treatments. Exosomes are small extracellular vesicles (EVs), ranging from 30 to 150 nm in size, that the majority of cells released them. Exosomes possess natural advantages such as high compatibility with living organisms and low potential for causing immune reactions, making them practical for delivering therapeutic agents like chemotherapy drugs, nucleic acids, and proteins. This review highlights recent advancements in using exosomes as an approach to providing medications for the treatment of melanoma.

Exosome therapeutics for non-small cell lung cancer tumorigenesis

Non-small cell lung cancer (NSCLC) remains an ongoing health concern, with poor treatment options and prognosis for many patients. Typically, individuals with lung cancer are detected at the middle and terminal stages, resulting in poor medical results due to lack of initial diagnosis and treatment. So, finding the initial specific and effective therapy options for lung cancer is necessary. In addition, exosomes are generally small lipid vesicles with a diameter in the nanometer range that are created and released by different cell types. Exosomes have therapeutic potential through delivering bioactive compounds including microRNAs, siRNAs, and therapeutic proteins to tumor cells, modifying the tumor microenvironment, and promoting anti-tumor immune responses. In recent years, exosome-based therapy has become known as an appropriate approach for NSCLC treatment. This review offers an overview of the possibility of exosome-based therapy for NSCLC, with an emphasis on mechanisms of action, preclinical research, and current clinical trials. Preclinical studies have shown that exosome-based therapy can decrease tumor growth, metastasis, and drug resistance in NSCLC models. Furthermore, ongoing clinical trials are looking at the safety and efficacy of exosome-based therapies in NSCLC patients, offering important insights into their translational prospects. Despite promising preclinical evidences, significant obstacles remain, including optimizing exosome isolation and purification techniques, standardizing production strategies, and developing scalable manufacturing processes. Overall, exosome-based therapy shows significant promise as a novel and various methods for treating NSCLC, with the potential to enhance patient outcomes and evolution cancer treatment.

The role of programmed death receptor (PD-)1/PD-ligand (L)1 in periodontitis and cancer

The programmed-death-ligand-1 (PD-L1) is an immune-modulating molecule that is constitutively expressed on various immune cells, different epithelial cells and a multitude of cancer cells. It is a costimulatory molecule that may impair T-cell mediated immune response. Ligation to the programmed-death-receptor (PD)-1, on activated T-cells and further triggering of the related signaling pathways can induce T-cells apoptosis or anergy. The upregulation of PD-L1 in various cancer types, including oral squamous cell carcinomas, was demonstrated and has been linked to immune escape of tumors and poor prognosis. A bidirectional relationship exists between the increased PD-L1 expression and periodontitis as well as the epithelial-mesenchymal transition (EMT), a process of interconversion of epithelial cells to mesenchymal cells that may induce immune escape of tumors. Interaction between exosomal PD-L1 and PD-1 on T-cells may cause immunosuppression by blocking the activation and proliferation of T-cells. The efficacy and importance of treatment with PD-1/PD-L1 checkpoint inhibitors and their prognostic influence on human cancers was demonstrated. Regarding PD-1/PD-L1 checkpoint inhibitors, resistances exist or may develop, basing on various factors. Further investigations of the underlying mechanisms will help to overcome the therapeutic limitations that result from resistances and to develop new strategies for the treatment of cancer.

Immunomodulatory effects of immune cell-derived extracellular vesicles in melanoma

Melanoma, recognized as one of the most immunogenic malignancies in humans, holds paramount significance in the realm of immunotherapy. However, the emergence of drug resistance and the occurrence of adverse drug reactions underscore the pressing need to explore increasingly personalized immunotherapeutic modalities. Extracellular Vesicles (EVs), pivotal derivatives of immune cells, assume pivotal roles by encapsulating proteins, lipids, and nucleic acids within bilayer lipid structures, thereby facilitating targeted delivery to other immune cells. This orchestrated process orchestrates critical functions including antigen presentation, immune modulation, and the induction of apoptosis in tumor cells. A burgeoning body of evidence underscores the vast therapeutic potential of EVs in melanoma treatment. This comprehensive review aims to delineate the roles of EVs derived from immune cells such as dendritic cells, natural killer cells, macrophages, and T cells in the context of melanoma patients, thereby furnishing invaluable insights for the future direction of melanoma immunotherapy.

Landscape of exosomes to modified exosomes: a state of the art in cancer therapy

Exosomes are a subpopulation of extracellular vesicles (EVs) that naturally originate from endosomes. They play a significant role in cellular communication. Tumor-secreted exosomes play a crucial role in cancer development and significantly contribute to tumorigenesis, angiogenesis, and metastasis by intracellular communication. Tumor-derived exosomes (TEXs) are a promising biomarker source of cancer detection in the early stages. On the other hand, they offer revolutionary cutting-edge approaches to cancer therapeutics. Exosomes offer a cell-free approach to cancer therapeutics, which overcomes immune cell and stem cell therapeutics-based limitations (complication, toxicity, and cost of treatment). There are multiple sources of therapeutic exosomes present (stem cells, immune cells, plant cells, and synthetic and modified exosomes). This article explores the dynamic source of exosomes (plants, mesenchymal stem cells, and immune cells) and their modification (chimeric, hybrid exosomes, exosome-based CRISPR, and drug delivery) based on cancer therapeutic development. This review also highlights exosomes based clinical trials and the challenges and future orientation of exosome research. We hope that this article will inspire researchers to further explore exosome-based cancer therapeutic platforms for precision oncology.

An iron-based metal-organic framework nanoplatform for enhanced ferroptosis and oridonin delivery as a comprehensive antitumor strategy

Ferroptosis is a recently discovered pathway for regulated cell death pathway. However, its efficacy is affected by limited iron content and intracellular ion homeostasis. Here, we designed a metal-organic framework (MOF)-based nanoplatform that incorporates calcium peroxide (CaO2) and oridonin (ORI). This platform can improve the tumor microenvironment and disrupt intracellular iron homeostasis, thereby enhancing ferroptosis therapy. Fused cell membranes (FM) were used to modify nanoparticles (ORI@CaO2@Fe-TCPP, NPs) to produce FM@ORI@CaO2@Fe-TCPP (FM@NPs). The encapsulated ORI inhibited the HSPB1/PCBP1/IREB2 and FSP1/COQ10 pathways simultaneously, working in tandem with Fe3+ to induce ferroptosis. Photodynamic therapy (PDT) guided by porphyrin (TCPP) significantly enhanced ferroptosis through excessive accumulation of reactive oxygen species (ROS). This self-amplifying strategy promoted robust ferroptosis, which could work synergistically with FM-mediated immunotherapy. In vivo experiments showed that FM@NPs inhibited 91.57% of melanoma cells within six days, a rate 5.6 times higher than chemotherapy alone. FM@NPs were biodegraded and directly eliminated in the urine or faeces without substantial toxicity. Thus, this study demonstrated that combining immunotherapy with efficient ferroptosis induction through nanotechnology is a feasible and promising strategy for melanoma treatment.

The effects of tumor-derived exosomes enriched with miRNA-211a on B16F10 cells

Introduction

Exosomes have emerged as a novel alternative delivery system for transporting small molecules. Tumor-derived exosomes (TEXs) possess anti-cancer properties and serve as natural carriers of microRNAs. Using this knowledge as a foundation, the current study evaluated the efficacy of delivering a miR-211 mimic via B16F10 cell-derived exosomes to block the growth and development of a melanoma cell line.

Material and methods

After exposing B16F10 cultured cells to serum-free media for 24 hours, we collected the supernatant. Subsequently, we purified the exosomes from the supernatant using a commercial kit. Scanning electron microscopy, transmission electron microscopy, dynamic light scattering, Western blot, and bicinchoninic acid protein assay were used to characterize exosomes. Following that, miR-211 mimic was loaded into exosomes (termed TEXomiR) via a modified calcium chloride procedure. The assessment of miR-211a loading efficiency into exosomes was conducted by analyzing its relative expression. MTT, annexin V/PI, and quantitative real-time polymerase chain reaction were used to measure the proliferation, apoptosis and relative expression of miR-211 target genes, respectively.

Results

Our study showed that the exosomes can deliver miR-211 mimic efficiently. The treatment of B16F10 cells with miR-211-enriched TEX downregulated miR-211 target genes, including brain-specific homeobox, vascular endothelial growth factor, and transforming growth factor-β receptor. The results indicated the antiproliferative effect of TEXomiR as time-dose-dependent. The flow cytometry evaluation showed that TEXomiR could induce the apoptosis of B16F10 cells.

Conclusions

Our data indicated that exosomes can be suitable carriers for miR-211 mimic. Moreover, TEXomiR via anti-cancer effects could inhibit the progression of melanoma cancer.

Quality and efficiency assessment of five extracellular vesicle isolation methods using the resistive pulse sensing strategy

Extracellular vesicles (EVs) have attracted great interest due to their great potential in disease diagnosis and therapy. The separation of EVs from complex biofluids with high purity is essential for the accurate analysis of EVs. Despite various methods, there is still no consensus on the best method for high-quality EV isolation and reliable mass production. Therefore, it is important to offer a standardized method for characterizing the properties (size distribution, particle concentration and purity) of EV preparations from different isolation methods. Herein, we employed a NanoCoulter Counter based on the resistive pulse sensing (RPS) strategy that enabled multi-parameter analysis of single EVs to compare the quality and efficiency of different EV isolation techniques including traditional differential ultracentrifugation, ultrafiltration, size exclusion chromatography, membrane affinity binding and polymer precipitation. The data revealed that the NanoCoulter Counter based on the RPS strategy was reliable and effective for the characterization of EVs. The results suggested that although higher particle concentrations were observed in three commercial isolation kits and ultrafiltration, traditional differential ultracentrifugation showed the highest purity. In conclusion, our results from the NanoCoulter Counter provided reliable evidence for the assessment of different EV isolation methods, which contributed to the development of EV-based disease biomarkers and treatments.

Exosomes: Their role in the diagnosis, progression, metastasis, and treatment of glioblastoma

Exosomes are crucial for the growth and spread of glioblastomas, an aggressive form of brain cancer. These tiny vesicles play a crucial role in the activation of signaling pathways and intercellular communication. They can also transfer a variety of biomolecules such as proteins, lipids and nucleic acids from donor to recipient cells. Exosomes can influence the immune response by regulating the activity of immune cells, and they are crucial for the growth and metastasis of glioblastoma cells. In addition, exosomes contribute to drug resistance during treatment, which is a major obstacle in the treatment of glioblastoma. By studying them, the diagnosis and prognosis of glioblastoma can be improved. Due to their high biocompatibility and lack of toxicity, they have become an attractive option for drug delivery. The development of exosomes as carriers of specific therapeutic agents could overcome some of the obstacles to effective treatment of glioblastoma. In this review, we address the potential of exosomes for the treatment of glioblastoma and show how they can be modified for this purpose.

Therapeutic effect of small extracellular vesicles from cytokine-induced memory-like natural killer cells on solid tumors

Small extracellular vesicles (sEV) derived from diverse natural killer (NK) cell lines have proven their exceptional antitumor activities. However, sEV from human primary NK cells, especially memory-like NK cells, are rarely utilized for cancer treatment. In this study, we obtained sEV from IL-12, IL-15 and IL-18 cultured human memory-like NK cells (mNK-sEV) that showed strong cytokine-secretory ability. It was uncovered that mNK-sEV entered cancer cells via macropinocytosis and induced cell apoptosis via caspase-dependent pathway. Compared to sEV from conventionally cultured NK cells (conNK-sEV), mNK-sEV inhibited tumor growth to a greater extent. Concomitantly, pharmacokinetics and biodistribution results validated a higher accumulation of mNK-sEV than conNK-sEV in tumors of xenografted murine models. Notably, elevated containment of granulysin (GNLY) within mNK-sEV, at least in part, may contribute to the enhanced therapeutic effect. Herein our results present that mNK-sEV can be a novel class of therapeutic reagent for effective cancer treatment.

Exosome-based anticancer vaccines: From Bench to bedside

Exosomes, a subset of extracellular vesicles, are released by all active cells and play a crucial role in intercellular communications. Exosomes could facilitate the transfer of various biologically active molecules, such as DNA, non-coding RNAs, and proteins, from donor to recipient cells, thereby participating in diverse biological and pathological processes. Besides, exosomes possess unique characteristics, including non-toxicity, low-immunogenicity, and stability within biological systems, rendering them highly advantageous for cancer drug development. Meanwhile, accumulating evidence suggests that exosomes originating from tumor cells and immune cells possess distinct composition profiles that play a direct role in anticancer immunotherapy. Of note, exosomes can transport their contents to specific cells, thereby exerting an impact on the phenotype and immune-regulatory functions of targeted cells. Therapeutic cancer vaccines, an emerging therapeutics of immunotherapy, could enhance antitumor immune responses by delivering a large number of tumor antigens, thereby augmenting the immune response against tumor cells. Therefore, the therapeutic rationale of cancer vaccines and exosome-based immunotherapy are almost similar to some extent, but some challenges have hindered their application in the clinical setting. Here, in this review, we first summarized the biogenesis, structure, compositions, and biological functions of exosomes. Then we described the roles of exosomes in cancer biology, particularly in tumor immunity. We also comprehensively reviewed current exosome-based anticancer vaccine development and we divided them into three types. Finally, we give some insights into clinical translation and clinical trial progress of exosome-based anticancer vaccines for future direction.

Exosomes-based immunotherapy for cancer: Effective components in the naïve and engineered forms

Today, cancer treatment is one of the main challenges for researchers. The main cause of tumor cell formation is mutations that lead to uncontrolled proliferation and inhibition of apoptosis in malignant cells. Tumor cells also create a microenvironment that can suppress the immune system cells' responses through various methods, including producing soluble factors and cell-to-cell communication. After being produced from tumor cells, exosomes can also affect the functions of other cells in this microenvironment. Various studies have shown that exosomes from different sources, including tumor cells and immune cells, can be used to treat cancers due to their characteristics. Since tumor cells are rich sources of various types of tumor peptides, they can induce anti-tumor responses. Immune cells also produce exosomes that mimic the functions of their cells of origin, such that exosomes derived from NK cells and CTLs can directly lead to their apoptosis after merging with tumor cells. However, many researchers have pointed out that naïve exosomes have a limited therapeutic function, and their therapeutic potential can be increased by manipulating and engineering them. There are various methods to modify exosomes and improve their therapeutic potential. In general, these methods are divided into two parts, which include changing the cell of origin of the exosome and encapsulating the exosome to carry different drugs. In this review, we will discuss the studies on the therapeutic use of naive and engineered exosomes and provide an update on new studies in this field.

Extracellular vesicles and cancer stem cells: a deadly duo in tumor progression

The global incidence of cancer is increasing, with estimates suggesting that there will be 26 million new cases and 17 million deaths per year by 2030. Cancer stem cells (CSCs) and extracellular vesicles (EVs) are key to the resistance and advancement of cancer. They play a crucial role in tumor dynamics and resistance to therapy. CSCs, initially discovered in acute myeloid leukemia, are well-known for their involvement in tumor initiation, progression, and relapse, mostly because of their distinct characteristics, such as resistance to drugs and the ability to self-renew. EVs, which include exosomes, microvesicles, and apoptotic bodies, play a vital role in facilitating communication between cells within the tumor microenvironment (TME). They have a significant impact on cellular behaviors and contribute to genetic and epigenetic changes. This paper analyzes the mutually beneficial association between CSCs and EVs, emphasizing their role in promoting tumor spread and developing resistance mechanisms. This review aims to investigate the interaction between these entities in order to discover new approaches for attacking the complex machinery of cancer cells. It highlights the significance of CSCs and EVs as crucial targets in the advancement of novel cancer treatments, which helps stimulate additional research, promote progress in ideas for cancer treatment, and provide renewed optimism in the effort to reduce the burden of cancer.

Extracellular Vesicles and Immune System Function: Exploring Novel Approaches to Colorectal Cancer Immunotherapy

This review explores the emerging role of extracellular vesicles (EVs) in modulating immune system function and their application in novel cancer immunotherapy strategies, with a focus on colorectal cancer (CRC). EVs, as carriers of bioactive molecules, have shown potential in enhancing immune responses and overcoming the limitations of traditional therapies. We discuss the biogenesis, types, and functional roles of immune cell-derived EVs, their interactions with cancer cells, and their implications in antitumor immunity. Challenges such as tumor heterogeneity and immune evasion are addressed, alongside the promising therapeutic prospects of EV-based strategies. This comprehensive analysis underscores the transformative potential of EVs in cancer treatment paradigms.

Microbiota-Derived Short-Chain Fatty Acids Boost Antitumoral Natural Killer Cell Activity

Background: The intestinal microbiota can regulate numerous host functions, including the immune response. Through fermentation, the microbiota produces and releases microbial metabolites such as short-chain fatty acids (SCFAs), which can affect host homeostasis. There is growing evidence that the gut microbiome can have a major impact on cancer. Specific gut microbial composition and metabolites are associated with tumor status in the host. However, their effects on the antitumor response have scarcely been investigated. Natural killer (NK) cells play an important role in antitumor immunity due to their ability to directly identify and eliminate tumor cells. Methods: The aim of this study was to investigate the effects of SCFAs on antitumoral NK cell activity, using NK-92 cell line. Results: Here, we describe how SCFAs can boost antitumoral NK cell activity. The SCFAs induced the release of NK extracellular vesicles and reduced the secretion of the anti-inflammatory cytokine IL-10. The SCFAs also increased the cytotoxicity of the NK cells against multiple myeloma cells. Conclusions: Our results indicate, for the first time, the enormous potential of SCFAs in regulating antitumoral NK cell defense, where modulation of the SCFAs' production could play a fundamental role in cancer immunotherapy.

Natural Killer Cell‐Derived Extracellular Vesicles as Potential Anti‐Viral Nanomaterials

In viral infections, natural killer (NK) cells exhibit anti-viral activity by inducing apoptosis in infected host cells and impeding viral replication through heightened cytokine release. Extracellular vesicles derived from NK cells (NK-EVs) also contain the membrane composition, homing capabilities, and cargo that enable anti-viral activity. These characteristics, and their biocompatibility and low immunogenicity, give NK-EVs the potential to be a viable therapeutic platform. This study characterizes the size, EV-specific protein expression, cell internalization, biocompatibility, and anti-viral miRNA cargo to evaluate the anti-viral properties of NK-EVs. After 48 h of NK-EV incubation in inflamed A549 lung epithelial cells, or conditions that mimic lung viral infections such as during COVID-19, cells treated with NK-EVs exhibit upregulated anti-viral miRNA cargo (miR-27a, miR-27b, miR-369-3p, miR-491-5p) compared to the non-treated controls and cells treated with control EVs derived from lung epithelial cells. Additionally, NK-EVs effectively reduce expression of viral RNA and pro-inflammatory cytokine (TNF-α, IL-8) levels in SARS-CoV-2 infected Vero E6 kidney epithelial cells and in infected mice without causing tissue damage while significantly decreasing pro-inflammatory cytokine compared to non-treated controls. Herein, this work elucidates the potential of NK-EVs as safe, anti-viral nanomaterials, offering a promising alternative to conventional NK cell and anti-viral therapies.

Evaluation of resazurin phenoxazine dye as a highly sensitive cell viability potency assay for natural killer cell-derived extracellular vesicle-based cancer biotherapeutics

Natural killer cell-derived extracellular vesicles (NK-EVs) are candidate biotherapeutics against various cancers. However, standardised potency assays are necessary for a reliable assessment of NK-EVs' cytotoxicity. This study aims to thoroughly evaluate a highly sensitive resazurin phenoxazine-based cell viability potency assay (measurement of the cellular redox metabolism) for quantifying the cytotoxicity of NK-EVs against leukaemia K562 cells (suspension model) and breast cancer MDA-MB-231 cells (adherent model) in vitro. The assay was evaluated based on common analytical parameters setforth by regulatory guidelines, including specificity, selectivity,accuracy, precision, linearity, range and stability. Our results revealed that this resazurin-based cell viability potency assay reliably and reproducibly measured a dose-response of NK-EVs' cytotoxic activity against both cancer models. The assay showed precision with 5% and 20% variation for intra-run and inter-run variability. The assay signal showed specificity and selectivity of NK-EVs against cancer target cells, as evidenced by the diminished viability of cancer cells following a 5-hour treatment with NK-EVs, without any detectable interference or background. The linearity analysis of target cancer cells revealed strong linearity for densities of 5000 K562 and 1000 MDA-MB-231 cells per test with a consistent range. Importantly, NK-EVs' dose-response for cytotoxicity showed a strong correlation (|ρ| ∼ 0.8) with the levels of known cytotoxic factors associated with the NK-EVs' corona (FasL, GNLY, GzmB, PFN and IFN-γ), thereby validating the accuracy of the assay. The assay also distinguished cytotoxicity changes in degraded NK-EVs, indicating the ability of the assay to detect the potential loss of sample integrity. Compared to other commonly reported bioassays (i.e., flow cytometry, cell counting, lactate dehydrogenase release assay, DNA-binding reporter assay and confluence assay), our results support this highly sensitive resazurin-based viability potency assay as a high-throughput and quantitative method for assessing NK-EVs' cytotoxicity against both suspension and adherent cancer models for evaluating NK-EVs' biotherapeutics.

Natural killer cell-derived exosome-based cancer therapy: from biological roles to clinical significance and implications

Natural killer (NK) cells are important immune cells in the organism and are the third major type of lymphocytes besides T cells and B cells, which play an important function in cancer therapy. In addition to retaining the tumor cell killing function of natural killer cells, natural killer cell-derived exosomes cells also have the characteristics of high safety, wide source, easy to preserve and transport. At the same time, natural killer cell-derived exosomes are easy to modify, and the engineered exosomes can be used in combination with a variety of current cancer therapies, which not only enhances the therapeutic efficacy, but also significantly reduces the side effects. Therefore, this review summarizes the source, isolation and modification strategies of natural killer cell-derived exosomes and the combined application of natural killer cell-derived engineered exosomes with other antitumor therapies, which is expected to accelerate the clinical translation process of natural killer cell-derived engineered exosomes in cancer therapy.

Different origin-derived exosomes and their clinical advantages in cancer therapy

Exosomes, as a class of small extracellular vesicles closely related to the biological behavior of various types of tumors, are currently attracting research attention in cancer diagnosis and treatment. Regarding cancer diagnosis, the stability of their membrane structure and their wide distribution in body fluids render exosomes promising biomarkers. It is expected that exosome-based liquid biopsy will become an important tool for tumor diagnosis in the future. For cancer treatment, exosomes, as the "golden communicators" between cells, can be designed to deliver different drugs, aiming to achieve low-toxicity and low-immunogenicity targeted delivery. Signaling pathways related to exosome contents can also be used for safer and more effective immunotherapy against tumors. Exosomes are derived from a wide range of sources, and exhibit different biological characteristics as well as clinical application advantages in different cancer therapies. In this review, we analyzed the main sources of exosomes that have great potential and broad prospects in cancer diagnosis and therapy. Moreover, we compared their therapeutic advantages, providing new ideas for the clinical application of exosomes.

Targeted Ferroptosis-Immunotherapy Synergy: Enhanced Antiglioma Efficacy with Hybrid Nanovesicles Comprising NK Cell-Derived Exosomes and RSL3-Loaded Liposomes

Ferroptosis therapy and immunotherapy have been widely used in cancer treatment. However, nonselective induction of ferroptosis in tumors is prone to immunosuppression, limiting the therapeutic effect of ferroptosis cancer treatment. To address this issue, this study reports a customized hybrid nanovesicle composed of NK cell-derived extracellular versicles and RSL3-loaded liposomes (hNRVs), aiming to establish a positive cycle between ferroptosis therapy and immunotherapy. Thanks to the enhanced permeability and retention effect and the tumor homing characteristics of NK exosomes, our data indicate that hNRVs can actively accumulate in tumors and enhance cellular uptake. FASL, IFN-γ, and RSL3 are released into the tumor microenvironment, where FASL derived from NK cells effectively lyses tumor cells. RSL3 downregulates the expression of GPX4 in the tumor, leading to the accumulation of LPO and ROS, and promotes ferroptosis in tumor cells. The accumulation of IFN-γ and TNF-α stimulates the maturation of dendritic cells and effectively induces the inactivation of GPX4, promoting lipid peroxidation, making them sensitive to ferroptosis and indirectly promoting the occurrence of ferroptosis. This study highlights the role of the customized hNRV platform in enhancing the effectiveness of synergistic treatment with selective delivery of ferroptosis inducers and immune activation against glioma without causing additional side effects on healthy organs.

Extracellular vesicles-powered immunotherapy: Unleashing the potential for safer and more effective cancer treatment

Cancer treatment has seen significant advancements with the introduction of Onco-immunotherapies (OIMTs). Although some of these therapies have received approval for use, others are either undergoing testing or are still in the early stages of development. Challenges persist in making immunotherapy widely applicable to cancer treatment. To maximize the benefits of immunotherapy and minimize potential side effects, it's essential to improve response rates across different immunotherapy methods. A promising development in this area is the use of extracellular vesicles (EVs) as novel delivery systems. These small vesicles can effectively deliver immunotherapies, enhancing their effectiveness and reducing harmful side effects. This article discusses the importance of integrating nanomedicines into OIMTs, highlighting the challenges with current anti-OIMT methods. It also explores key considerations for designing nanomedicines tailored for OIMTs, aiming to improve upon existing immunotherapy techniques. Additionally, the article looks into innovative approaches like biomimicry and the use of natural biomaterial-based nanocarriers (NCs). These advancements have the potential to transform the delivery of immunotherapy. Lastly, the article addresses the challenges of moving OIMTs from theory to clinical practice, providing insights into the future of using advanced nanotechnology in cancer treatment.

Extracellular vesicle-mediated drug delivery in breast cancer theranostics

Breast cancer (BC) continues to be a significant global challenge due to drug resistance and severe side effects. The increasing prevalence is alarming, requiring new therapeutic approaches to address these challenges. At this point, Extracellular vesicles (EVs), specifically small endosome-released nanometer-sized EVs (SEVs) or exosomes, have been explored by literature as potential theranostics. Therefore, this review aims to highlight the therapeutic potential of exosomes in BC, focusing on their advantages in drug delivery and their ability to mitigate metastasis. Following the review, we identified exosomes' potential in combination therapies, serving as miRNA carriers and contributing to improved anti-tumor effects. This is evident in clinical trials investigating exosomes in BC, which have shown their ability to boost chemotherapy efficacy by delivering drugs like paclitaxel (PTX) and doxorubicin (DOX). However, the translation of EVs into BC therapy is hindered by various challenges. These challenges include the heterogeneity of EVs, the selection of the appropriate parent cell, the loading procedures, and determining the optimal administration routes. Despite the promising therapeutic potential of EVs, these obstacles must be addressed to realize their benefits in BC treatment.