Dendritic cell-derived exosomes need to activate both T and B cells to induce antitumor immunity

Enhancing preventive and therapeutic cancer vaccine efficacy through biotherapeutic ligand-associated extracellular vesicles

Extracellular vesicles (EVs), secreted by almost all living cells, have gained significant attention for their role in intercellular communication and their potential as versatile carriers for biotherapeutics. However, the clinical translation of EV-based therapies faces significant challenges, primarily due to the lack of efficient methods for loading biotherapeutic agents into EVs. This study introduces a simple, reproducible strategy for the simultaneous incorporation of various biotherapeutics within EVs. The process is gentle and preserves the essential physicochemical and biological characteristics of EVs, thereby protecting labile ligands from premature degradation and elimination. The binding and uptake efficiency of EVs by target cells reached approximately 97 % within 24 h of incubation. Administration of EVs loaded with oligodeoxynucleotides (ODN) resulted in a 4-fold increase in IFNγ+ CD4+ T cells and a 5-fold increase in IFNγ+ CD8+ T cells in the spleens and lymph nodes. Additionally, the co-administration of EVs with ODN and ovalbumin (OVA) induced elevated Th1-biased antibody responses and antigen-specific cytotoxic T-cell responses, providing long-lasting complete protection in 60 % of mice against T-cell thymoma challenge. Furthermore, EVs associated with three different ligands (OVA, CpG-ODN, and α-GalCer) effectively regressed established murine melanoma and significantly improved survival rates in mice. This study presents a powerful and promising approach to overcoming the limitations of EV-based cancer vaccines, advancing the development of effective cancer immunotherapies. SUMMARY: Immunization with EVs that are co-associated with antigen and biotherapeutic cargo through a lyophilization-based technique elicits potent anti-cancer immunity.

Programmable bionanomaterials for revolutionizing cancer immunotherapy

Cancer immunotherapy involves a cutting-edge method that utilizes the immune system to detect and eliminate cancer cells. It has shown substantial effectiveness in treating different types of cancer. As a result, its growing importance is due to its distinct benefits and potential for sustained recovery. However, the general deployment of this treatment is hindered by ongoing issues in maintaining minimal toxicity, high specificity, and prolonged effectiveness. Nanotechnology offers promising solutions to these challenges due to its notable attributes, including expansive precise surface areas, accurate ability to deliver drugs and controlled surface chemistry. This review explores the current advancements in the application of nanomaterials in cancer immunotherapy, focusing on three primary areas: monoclonal antibodies, therapeutic cancer vaccines, and adoptive cell treatment. In adoptive cell therapy, nanomaterials enhance the expansion and targeting capabilities of immune cells, such as T cells, thereby improving their ability to locate and destroy cancer cells. For therapeutic cancer vaccines, nanoparticles serve as delivery vehicles that protect antigens from degradation and enhance their uptake by antigen-presenting cells, boosting the immune response against cancer. Monoclonal antibodies benefit from nanotechnology through improved delivery mechanisms and reduced off-target effects, which increase their specificity and effectiveness. By highlighting the intersection of nanotechnology and immunotherapy, we aim to underscore the transformative potential of nanomaterials in enhancing the effectiveness and safety of cancer immunotherapies. Nanoparticles' ability to deliver drugs and biomolecules precisely to tumor sites reduces systemic toxicity and enhances therapeutic outcomes.

Tumor Microenvironment-Derived Exosomes: A Double-Edged Sword for Advanced T Cell-Based Immunotherapy

The tumor microenvironment (TME) plays a crucial role in cancer progression and immune evasion, partially mediated by the activity of the TME-derived exosomes. These extracellular vesicles are pivotal in shaping immune responses through the transfer of proteins, lipids, and nucleic acids between cells, facilitating a complex interplay that promotes tumor growth and metastasis. This review delves into the dual roles of exosomes in the TME, highlighting both their immunosuppressive functions and their emerging therapeutic potential. Exosomes can inhibit T cell function and promote tumor immune escape by carrying immune-modulatory molecules, such as PD-L1, yet they also hold promise for cancer therapy as vehicles for delivering tumor antigens and costimulatory signals. Additionally, the review discusses the intricate crosstalk mediated by exosomes among various cell types within the TME, influencing both cancer progression and responses to immunotherapies. Moreover, this highlights current challenges and future directions. Collectively, elucidating the detailed mechanisms by which TME-derived exosomes mediate T cell function offers a promising avenue for revolutionizing cancer treatment. Understanding these interactions allows for the development of targeted therapies that manipulate exosomal pathways to enhance the immune system's response to tumors.

Extracellular vesicles derived from antigen-presenting cells pulsed with foot and mouth virus vaccine-antigens act as carriers of viral proteins and stimulate B cell response

Foot and mouth disease (FMD) is a highly contagious infection caused by FMD-virus (FMDV) that affects livestock worldwide with significant economic impact. The main strategy for the control is vaccination with FMDV chemically inactivated with binary ethylenimine (FMDVi). In FMDV infection and vaccination, B cell response plays a major role by providing neutralizing/protective antibodies in animal models and natural hosts. Extracellular vesicles (EVs) and small EVs (sEVs) such as exosomes are important in cellular communication. EVs secreted by antigen-presenting cells (APC) like dendritic cells (DCs) participate in the activation of B and T cells through the presentation of native antigen membrane-associated to B cells or by transferring MHC-peptide complexes to T cells and even complete antigens from DCs. In this study, we demonstrate for the first time that APC activated with the FMDVi O1 Campos vaccine-antigens secrete EVs expressing viral proteins/peptides that could stimulate FMDV-specific immune response. The secretion of EVs-FMDVi is a time-dependent process and can only be isolated within the first 24 h post-activation. These vesicles express classical EVs markers (CD9, CD81, and CD63), along with immunoregulatory molecules (MHC-II and CD86). With an average size of 155 nm, they belong to the category of EVs. Studies conducted in vitro have demonstrated that EVs-FMDVi express antigens that can stimulate a specific B cell response against FMDV, including both marginal zone B cells (MZB) and follicular B cells (FoB). These vesicles can also indirectly or directly affect T cells, indicating that they express both B and T epitopes. Additionally, lymphocyte expansion induced by EVs-FMDVi is greater in splenocytes that have previously encountered viral antigens in vivo. The present study sheds light on the role of EVs derived from APC in regulating the adaptive immunity against FMDV. This novel insight contributes to our current understanding of the immune mechanisms triggered by APC during the antiviral immune response. Furthermore, these findings may have practical implications for the development of new vaccine platforms, providing a rational basis for the design of more effective vaccines against FMDV and other viral diseases.

SARS-CoV-2 envelope protein-derived extracellular vesicles act as potential media for viral spillover

Extracellular vesicles (EVs) are shown to be a novel viral transmission model capable of increasing a virus's tropism. According to our earlier research, cells infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) or transfected with envelope protein plasmids generate a novel type of EVs that are micrometer-sized and able to encase virus particles. Here, we showed the capacity of these EVs to invade various animals both in vitro and in vivo independent of the angiotensin-converting enzyme 2 receptor. First, via macropinocytosis, intact EVs produced from Vero E6 (monkey) cells were able to enter cells from a variety of animals, including cats, dogs, bats, hamsters, and minks, and vice versa. Second, when given to zebrafish with cutaneous wounds, the EVs showed favorable stability in aqueous environments and entered the fish. Moreover, infection of wild-type (WT) mice with heterogeneous EVs carrying SARS-CoV-2 particles led to a strong cytokine response and a notable amount of lung damage. Conversely, free viral particles did not infect WT mice. These results highlight the variety of processes behind viral transmission and cross-species evolution by indicating that EVs may be possible vehicles for SARS-CoV-2 spillover and raising risk concerns over EVs' potential for viral gene transfer.

Extracellular vesicles in cancer therapy: Roles, potential application, and challenges

Extracellular vesicles (EVs) have emerged as a novel cell-free strategy for the treatment of many diseases including cancer as they play important roles in cancer development and progression. Considering their natural capacity to facilitate cell-to-cell communication as well as their high physiochemical stability and biocompatibility, EVs serve as superior delivery systems for a wide range of therapeutic agents, including medicines, nanomaterials, nucleic acids, and proteins. Therefore, EVs-based cancer therapy is of greater interest to researchers. Mounting studies indicate that EVs can be improved in efficiency, specificity, and safety for cancer therapy. However, their heterogeneity of physicochemical properties and functions is not fully understood, hindering the achievement of bioactive EVs with high yield and purity. Herein, we paid more attention to the EVs applications and their significance in cancer therapy.

Modification of immune cell-derived exosomes for enhanced cancer immunotherapy: current advances and therapeutic applications

Cancer immunotherapy has revolutionized the approach to cancer treatment of malignant tumors by harnessing the body's immune system to selectively target cancer cells. Despite remarkable advances, there are still challenges in achieving successful clinical responses. Recent evidence suggests that immune cell-derived exosomes modulate the immune system to generate effective antitumor immune responses, making them a cutting-edge therapeutic strategy. However, natural exosomes are limited in clinical application due to their low drug delivery efficiency and insufficient antitumor capacity. Technological advancements have allowed exosome modifications to magnify their intrinsic functions, load different therapeutic cargoes, and preferentially target tumor sites. These engineered exosomes exert potent antitumor effects and have great potential for cancer immunotherapy. In this review, we describe ingenious modification strategies to attain the desired performance. Moreover, we systematically summarize the tumor-controlling properties of engineered immune cell-derived exosomes in innate and adaptive immunity. Collectively, this review provides a comprehensive and intuitive guide for harnessing the potential of modified immune cell-derived exosome-based approaches, offering valuable strategies to enhance and optimize cancer immunotherapy.

Tumor-derived small extracellular vesicles in cancer invasion and metastasis: molecular mechanisms, and clinical significance

The production and release of tumor-derived small extracellular vesicles (TDSEVs) from cancerous cells play a pivotal role in the propagation of cancer, through genetic and biological communication with healthy cells. TDSEVs are known to orchestrate the invasion-metastasis cascade via diverse pathways. Regulation of early metastasis processes, pre-metastatic niche formation, immune system regulation, angiogenesis initiation, extracellular matrix (ECM) remodeling, immune modulation, and epithelial-mesenchymal transition (EMT) are among the pathways regulated by TDSEVs. MicroRNAs (miRs) carried within TDSEVs play a pivotal role as a double-edged sword and can either promote metastasis or inhibit cancer progression. TDSEVs can serve as excellent markers for early detection of tumors, and tumor metastases. From a therapeutic point of view, the risk of cancer metastasis may be reduced by limiting the production of TDSEVs from tumor cells. On the other hand, TDSEVs represent a promising approach for in vivo delivery of therapeutic cargo to tumor cells. The present review article discusses the recent developments and the current views of TDSEVs in the field of cancer research and clinical applications.

Immune Cell-Derived Exosomes in Inflammatory Disease and Inflammatory Tumor Microenvironment: A Review

Inflammation is a common feature of many inflammatory diseases and tumors, and plays a decisive role in their development. Exosomes are extracellular vesicles unleashed by assorted types of cells, and it is widely known that exosomes of different immune cell sources play different functions. Exosome production has recently been reported for immune cells comprising macrophages, T cells, B cells, and dendritic cells (DCs). Immune cell-derived exosomes are involved in a variety of inflammatory responses.Herein, we summarize and review the role of macrophages, T cells, B cells, and dendritic cells (DC) in inflammatory diseases, with a focus on the role of immune cell-derived exosomes in osteoarthritis, rheumatoid arthritis, and the inflammatory tumor microenvironment (TME).These findings are expected to be important for developing new treatments for inflammatory diseases and ameliorating tumor-related inflammation.

Tuning spacer length improves the functionality of the nanobody-based VEGFR2 CAR T cell

BACKGROUND

The chimeric antigen receptor-expressing T (CAR-T) cells for cancer immunotherapy have obtained considerable clinical importance. CAR T cells need an optimized intracellular signaling domain to get appropriately activated and also for the proper antigen recognition, the length and composition of the extracellular spacer are critical factors.

RESULTS

We constructed two third-generation nanobody-based VEGFR2-CARs containing either IgG1 hinge-CH2-CH3 region or hinge-only as long or short extracellular spacers, respectively. Both CARs also contained intracellular activating domains of CD28, OX40, and CD3ζ. The T cells from healthy individuals were transduced efficiently with the two CARs, and showed increased secretion of IL-2 and IFN-γ cytokines, and also CD69 and CD25 activation markers along with cytolytic activity after encountering VEGFR2+ cells. The VEGFR2-CAR T cells harboring the long spacer showed higher cytokine release and CD69 and CD25 expression in addition to a more efficient cytolytic effect on VEGFR2+ target cells.

CONCLUSIONS

The results demonstrated that the third-generation anti-VEGFR2 nanobody-based CAR T cell with a long spacer had a superior function and potentially could be a better candidate for solid tumor treatment.

Tumor Antigen-Primed Dendritic Cell-Derived Exosome Synergizes with Colony Stimulating Factor-1 Receptor Inhibitor by Modulating the Tumor Microenvironment and Systemic Immunity

Dendritic cell-derived exosomes (Dex) have overcome the disadvantages associated with dendritic cell (DC) vaccines, such as cost effectiveness, stability, and sensitivity to the systemic microenvironment. However, in clinical trials, Dex failed to provide satisfactory results because of many reasons, including inadequate maturation of DC as well as the immunosuppressive tumor microenvironment (TME). Hence, culturing DCs in the presence of a maturation cocktail showed an induced expression of MHCs and co-stimulatory molecules. Additionally, targeting the colony stimulating factor-1 (CSF-1)/CSF-1 receptor (CSF-1R) signaling pathway by a CSF-1R inhibitor could deplete tumor-associated macrophages (TAMs) and myeloid-derived suppressor cells (MDSCs) which are responsible for immunosuppressive TME. Hence, in this study, mDexTA were isolated from bone marrow-derived DC cultured in the presence of a novel maturation cocktail and tumor antigen. mDexTA showed elevated expression of major histocompatibility complexes (MHCs) and co-stimulatory molecules and was found capable of activating naïve DC and T cells in vitro more efficiently when compared to imDexTA isolated from immature DCs. In addition, PLX-3397, a small molecule inhibitor of CSF-1/CSF-1R, was used in combination to enhance the antitumor efficacy of mDexTA. PLX-3397 showed dose-dependent toxicity against bone marrow-derived macrophages (BMDMs). In the B16-F10 murine melanoma model, we found that the combination treatment delayed tumor growth and improved survival compared to the mice treated with mDexTA alone by enhancing the CD8 T cells infiltration in TME. mDexTA when combined with PLX-3397 modulated the TME by shifting the Th1/Th2 toward a dominant Th1 population and depleting the TAMs and MDSCs. Interestingly, PLX-3397-induced FoxP3 expression was diminished when it was used in combination with mDexTA. Combination treatment also induced favorable systemic antitumor immunity in the spleen and lymph node. In conclusion, our findings provide insights into the synergy between mDexTA-based immunotherapy and PLX-3397 as the combination overcame the disadvantages associated with monotherapy and offer a therapeutic strategy for the treatment of solid tumors including melanoma.

Umbilical Cord Blood-Derived M1 Macrophage Exosomes Loaded with Cisplatin Target Ovarian Cancer In Vivo and Reverse Cisplatin Resistance

We investigated the therapeutic efficacy of umbilical cord blood (UCB)-derived M1 macrophage exosomes loaded with cisplatin (CIS) in ovarian cancer and platinum resistance. M1 macrophages were purified by using CD14 magnetic beads and characterized by flow cytometry. Our analyses included morphology, particle size, particle concentration, potential, drug loading capacity, counts of entry into cells, antitumor effect in vivo, and the ability to reverse drug resistance. A2780, SKOV3, and A2780/DDP, SKOV3/DDP ovarian cancer cells (CIS-sensitive and CIS-resistant cell lines, respectively) were treated with CIS or CIS-loaded M1 macrophage exosomes (M1exoCISs). The encapsulation efficiency of CIS loading into M1 macrophage exosomes was approximately 30%. In vitro, M1exoCIS treatment reduced the CIS IC50 values of both A2780, SKOV3, and A2780/DDP, SKOV3/DDP cells. We evaluated the effect of M1exoCIS on tumor growth using a mouse ovarian cancer subcutaneous transplantation tumor model inoculated with A2780/DDP cells. M1exoCIS was observed in the liver, spleen, and tumor sites 24 h posttreatment; the fluorescence intensity of M1exoCIS is higher than that of CIS. After 7 days, M1exoCIS significantly inhibited the growth of subcutaneously transplanted tumors compared with CIS alone and had a longer survival time. Moreover, the toxicity test shows that M1exoCIS has less hepatorenal toxicity than CIS. To investigate the mechanism of M1exoCIS targeting, homing, and reversing drug resistance, we performed RT-PCR, Western blotting, and Proteome Profiler Human Receptor Array analyses. We found that A2780 and A2780/DDP cells expressed the integrin β1/CD29 receptor, while M1 exosomes expressed integrin β1/CD29. In addition, M1exos carries long noncoding RNA H19, implicated in PTEN protein upregulation and miR-130a and Pgp gene downregulation, leading to the reversal of CIS drug resistance. Therefore, UCB-derived M1exoCIS target tumor sites of ovarian cancer in vivo and can be used to increase the CIS sensitivity and cytotoxicity.

The therapeutic potential of exosomes in lung cancer

BACKGROUND

Lung cancer (LC) is one of the most common malignancies globally. Besides early detection and surgical resection, there is currently no effective curative treatment for metastatic advanced LC. Exosomes are endogenous nano-extracellular vesicles produced by somatic cells that play an important role in the development and maintenance of normal physiology. Exosomes can carry proteins, peptides, lipids, nucleic acids, and various small molecules for intra- and intercellular material transport or signal transduction. LC cells can maintain their survival, proliferation, migration, invasion, and metastasis, by producing or interacting with exosomes. Basic and clinical data also show that exosomes can be used to suppress LC cell proliferation and viability, induce apoptosis, and enhance treatment sensitivity. Due to the high stability and target specificity, good biocompatibility, and low immunogenicity of exosomes, they show promise as vehicles of LC therapy.

CONCLUSION

We have written this comprehensive review to communicate the LC treatment potential of exosomes and their underlying molecular mechanisms. We found that overall, LC cells can exchange substances or crosstalk with themselves or various other cells in the surrounding TME or distant organs through exosomes. Through this, they can modulate their survival, proliferation, stemness, migration, and invasion, EMT, metastasis, and apoptotic resistance.

Recent progress in exosome research: isolation, characterization and clinical applications

Exosomes, a kind of nano-vesicles released by various cell types, carry a variety of "cargos" including proteins, RNAs, DNAs and lipids. There is substantial evidence that exosomes are involved in intercellular communication by exchanging "cargos" among cells and play important roles in cancer development. Because of the different expressions of "cargos" carried by exosomes in biological fluids under physiological and pathological conditions, exosomes have the potential as a minimally invasive method of liquid biopsy for cancer diagnosis and prognosis. In addition, due to their good biocompatibility, safety, biodistribution and low immunogenicity, exosomes also have potential applications in the development of promising cancer treatment methods. In this review, we summarize the recent progress in the isolation and characterization techniques of exosomes. Moreover, we review the biological functions of exosomes in regulating tumor metastasis, drug resistance and immune regulation during cancer development and outline the applications of exosomes in cancer therapy.

Dendritic Cell-Derived Exosomes in Cancer Immunotherapy

Exosomes are nanoscale vesicles released by diverse types of cells for complex intercellular communication. Numerous studies have shown that exosomes can regulate the body's immune response to tumor cells and interfere with the tumor microenvironment (TME). In clinical trials on dendritic cell (DC)-based antitumor vaccines, no satisfactory results have been achieved. However, recent studies suggested that DC-derived exosomes (DEXs) may be superior to DC-based antitumor vaccines in avoiding tumor cell-mediated immunosuppression. DEXs contain multiple DC-derived surface markers that capture tumor-associated antigens (TAAs) and promote immune cell-dependent tumor rejection. These findings indicate the necessity of the further development and improvement of DEX-based cell-free vaccines to complement chemotherapy, radiotherapy, and other immunotherapies. In this review, we highlighted the recent progress of DEXs in cancer immunotherapy, particularly by concentrating on landmark studies and the biological characterization of DEXs, and we summarized their important role in the tumor immune microenvironment (TIME) and clinical application in targeted cancer immunotherapy. This review could enhance comprehension of advances in cancer immunotherapy and contribute to the elucidation of how DEXs regulate the TIME, thereby providing a reference for utilizing DEX-based vaccines in clinical practice.

Exosomal delivery of cannabinoids against cancer

Exosomes are extracellular vesicles (EVs) originating from endosomes that play a role in cellular communication. These vesicles which mimic the parental cells that release them are promising candidates for targeted drug delivery and therapeutic applications against cancer because of their favorable biocompatibility, specific targeting, low toxicity, and immunogenicity. Currently, Delta-9-tetrahydrocannabinol (THC), cannabidiol (CBD) and other cannabinoids (e.g., CBG, THCV, CBC), are being explored for their anticancer and anti-proliferative properties. Several mechanisms, including cell cycle arrest, proliferation inhibition, activation of autophagy and apoptosis, inhibition of adhesion, metastasis, and angiogenesis have been proposed for their anticancer activity. EVs could be engineered as cannabinoid delivery systems for tumor-specificity leading to superior anticancer effects. This review discusses current techniques for EV isolation from various sources, characterization and strategies to load them with cannabinoids. More extensively, we culminate information available on different sources of EVs that have anticancer activity, mechanism of action of cannabinoids against various wild type and resistant tumors and role of CBD in histone modifications and cancer epigenetics. We have also enumerated the role of EVs containing cannabinoids against various tumors and in chemotherapy induced neuropathic pain.

Revolutionizing anti-tumor therapy: unleashing the potential of B cell-derived exosomes

B cells occupy a vital role in the functioning of the immune system, working in tandem with T cells to either suppress or promote tumor growth within the tumor microenvironment(TME). In addition to direct cell-to-cell communication, B cells and other cells release exosomes, small membrane vesicles ranging in size from 30-150 nm, that facilitate intercellular signaling. Exosome research is an important development in cancer research, as they have been shown to carry various molecules such as major histocompatibility complex(MHC) molecules and integrins, which regulate the TME. Given the close association between TME and cancer development, targeting substances within the TME has emerged as a promising strategy for cancer therapy. This review aims to present a comprehensive overview of the contributions made by B cells and exosomes to the tumor microenvironment (TME). Additionally, we delve into the potential role of B cell-derived exosomes in the progression of cancer.

Exosome-mediated crosstalk between tumor cells and innate immune cells: implications for cancer progression and therapeutic strategies

The increasing number of cancer-associated deaths despite the substantial improvement in diagnosis and treatment has sparked discussions on the need for novel biomarkers and therapeutic strategies for cancer. Exosomes have become crucial players in tumor development and progression, largely due to the diverse nature of their cargo content released to recipient cells. Importantly, exosome-mediated crosstalk between tumor and stromal cells is essential in reprogramming the tumor microenvironment to facilitate tumor progression. As a result, exosomes have gradually become a marker for the early diagnosis of many diseases and an important tool in drug delivery systems. However, the precise mechanisms by which exosomes participate in tumor progression remain elusive, multifaceted, and a double-edged sword, thus requiring further clarification. The available evidence suggests that exosomes can facilitate communication between innate immune cells and tumor cells to either support or inhibit tumor progression. Herein, this review focused on exosome-mediated intercellular communication between tumor cells and macrophages, neutrophils, mast cells, monocytes, dendritic cells, and natural killer cells. Specifically, how such intercellular communication affects tumor progression has been described. It has also been discussed that, depending on their cargo, exosomes can suppress or promote tumor cell progression. In addition, the potential application of exosomes and strategies to target exosomes in cancer treatment has been comprehensively discussed.

Dendritic cell-derived exosomes: A new horizon in personalized cancer immunotherapy?

Dendritic cells (DCs) release nanometer-sized membrane vesicles known as dexosomes, containing different molecules, particularly proteins, for presenting antigens, i.e., major histocompatibility complex (MHC)-I/II and CD86. Dexosomes can, directly and indirectly, stimulate antigen-reactive CD8⁺ and CD4⁺ T cell responses. Antigen-loaded dexosomes can lead to the development of potent anti-tumoral immune responses. Notably, developing dexosome-based cell-free vaccines could serve as a new vaccination platform in the era of immunotherapy for various cancers. Furthermore, combining dexosomes vaccination strategies with other treatment approaches can considerably increase tumor-specific T cell responses. Herein, we aimed to review how dexosomes interact with immune cells, e.g., CD4⁺ and CD8⁺ T cells and natural killer (NK) cells. Besides, we discussed the limitations of this approach and suggested potential strategies to improve its effectiveness for affected patients.

Extracellular vesicles of immune cells; immunomodulatory impacts and therapeutic potentials

Extracellular vesicles (EVs) are a diverse collection of lipid bilayer-membrane-bound particles which are released from cells into the extracellular space and biologic fluids. In multicellular organisms, these vesicles facilitate the exchange of bioactive compounds such as RNA, DNA, proteins, various metabolites, and lipids between the cells. EVs are produced and released by almost all eukaryotic cells including immune cells and can have immunomodulating effects by either stimulation or suppression of their activities. This immune-modulating feature may provide a promising strategy for treating immune-mediated diseases such as cancer, neurodegenerative diseases, autoimmune disorders and graft-versus-host disease. Moreover, immune cell-derived EVs have received attention as potential biomarkers for being used as diagnostic tools and preventive strategies such as for developing vaccines. In this review, we focus on the EVs produced by different immune cell types, their effects on the immune system, and highlight their potential applications for immunotherapy.

Antigen-Loaded Extracellular Vesicles Induce Responsiveness to Anti-PD-1 and Anti-PD-L1 Treatment in a Checkpoint Refractory Melanoma Model

Extracellular vesicles (EV) are important mediators of intercellular communication and are potential candidates for cancer immunotherapy. Immune checkpoint blockade, specifically targeting the programmed cell death protein 1 (PD-1)/programmed death-ligand 1 (PD-L1) axis, mitigates T-cell exhaustion, but is only effective in a subset of patients with cancer. Reasons for therapy resistance include low primary T-cell activation to cancer antigens, poor antigen presentation, and reduced T-cell infiltration into the tumor. Therefore, combination strategies have been extensively explored. Here, we investigated whether EV therapy could induce susceptibility to anti-PD-1 or anti-PD-L1 therapy in a checkpoint-refractory B16 melanoma model. Injection of dendritic cell-derived EVs, but not checkpoint blockade, induced a potent antigen-specific T-cell response and reduced tumor growth in tumor-bearing mice. Combination therapy of EVs and anti-PD-1 or anti-PD-L1 potentiated immune responses to ovalbumin- and α-galactosylceramide-loaded EVs in the therapeutic model. Moreover, combination therapy resulted in increased survival in a prophylactic tumor model. This demonstrates that EVs can induce potent antitumor immune responses in checkpoint refractory cancer and induce anti-PD-1 or anti-PD-L1 responses in a previously nonresponsive tumor model.

Immunocyte Derived Exosomes: Insight into the Potential Chemo-immunotherapeutic Nanocarrier Targeting the Tumor Microenvironment

"Cancer" is a dreadful immune-pathological condition that is characterized by anti-inflammatory and tumorigenic responses, elicited by the infiltrating immune cells in the vicinity of an uncontrollably proliferative tumor in the tumor microenvironment (TME). The TME offers a conducive microenvironment that supports cancer cell survival by modulating the host immune defense. Recent advancement in exosomal research has shown exosomes, originating from immune cells as well as the cancer cells, have immense potential for suppressing cancer progression and survival in the TME. Additionally, exosomes, irrespective of their diverse sources, have been reported to be efficient nanocarriers for cancer therapeutics with the ability for targeted delivery due to their biogenic nature, ease of cellular uptake, and scope for functionalization with biomolecules like peptides, aptamers, targeting ligands, etc. Immune cell-derived exosomes per se have been found efficacious against cancer owing to their immune-stimulant properties (in either naive or antigen primed form) even without loading any of cancer therapeutics or targeting ligand conjugation. Nevertheless, exosomes are being primarily explored as nanovesicular carriers for therapeutic molecules with different loading and targeting strategies, and the synergism between immunotherapeutic behavior of exosomes and the anticancer effect of the therapeutic molecules is yet to be explored. Hence, this review focuses specifically on the possible strategies to modulate the immunological nature of the source immune cells to obtain immune stimulant exosomes and bring these into the spotlight as chemo-immunotherapeutic nanovesicles, that can easily target and modulate the TME.

Dendritic cell derived exosomes loaded neoantigens for personalized cancer immunotherapies

Despite the promising potential of cancer vaccine, their efficacy has been limited in clinical trials and improved methods are urgently needed. Here we designed a nanovaccine platform that contains dendritic cell derived exosomes carriers and patient-specific neoantigens for individualized immunotherapies. The nanovaccine exhibited convenient cargo loading and prolonged cargo transportation to the lymph nodes, followed by eliciting potent antigen specific broad-spectrum T-cell and B-cell-mediated immune responses with great biosafety and biocompatibility. Strikingly, delivery of neoantigen-exosome nanovaccine significantly prohibited tumor growth, prolonged survival, delayed tumor occurrences with long-term memory, eliminated the lung metastasis in the therapeutic, prophylactic and metastatic B16F10 melanoma as well as therapeutic MC-38 models, respectively. Additionally, exosome-based nanovaccine demonstrated synergistic antitumor response superior to liposomal formulation due to presence of exosomal proteins. Collectively, our research indicated improved strategies for cell free vaccines and suggested exosome-based nanoplatform for cancer immunotherapy and personalized nanotechnology. These findings represent a powerful pathway to generate individualized nanovaccine rapidly for clinical application.

Multi-functional extracellular vesicles: Potentials in cancer immunotherapy

Cancer immunotherapy (CIT) has revolutionized cancer treatment. However, the application of CIT is limited by low response rates and significant individual differences owing to a deficit in 1) immune recognition and 2) immune effector function. Extracellular vesicles (EVs) are cell-derived lipid bilayer-enclosed vesicles that mediate intercellular communication. The specific structure and content of EVs allows for multi-functional modulation of tumor immunity. Given their high biocompatibility, homologous targeting, and permeability across biological barriers, EVs have been evaluated as ideal carriers for promoting the efficacy and specificity of CIT. Herein, we first discuss the role of EVs in regulating tumor immunity and focus on the advantages of using EVs as a therapeutic tool for cancer treatment from a clinical perspective. Further, we outline the current progress in the development of biohybrid EVs for CIT and multi-functional EV-based strategies for overcoming the deficits in tumor immunity. Finally, we discuss the challenges associated with EV-based CIT and future perspectives in the context of ongoing clinical trials involving EV-based therapies, thus offering valuable insights into the future of multi-functional EVs in CIT.

Exosomes Derived from Immune Cells: The New Role of Tumor Immune Microenvironment and Tumor Therapy

Exosomes are small vesicles secreted by living cells, with a typical lipid bilayer structure. They carry a variety of proteins, lipids, RNA and other important information, play an important role in the transmission of substances and information between cells, and gradually become a marker for early diagnosis of many diseases and an important tool in drug delivery system. Immune cells are an important part of tumor microenvironment, and they can affect tumor progression by secreting a variety of immunoreactive substances. This review focuses on the effects of various immune cell-derived exosomes on tumor cells, different immune cells and other stromal cells in tumor microenvironment. Exosomes derived from different immune cells can not only reshape a pro-inflammatory microenvironment to inhibit tumor progression, but also promote tumor progression by inhibiting the killing effect of NK cells, CD8⁺T cells and other cells or promoting tumor cells and immunosuppressive immune cells. In addition, we also discussed that some exosomes derived from immune cells (such as DC, M1 macrophages and neutrophils) play a tumor inhibitory role after being engineered.

New Therapeutics for Extracellular Vesicles: Delivering CRISPR for Cancer Treatment

Cancers are defined by genetic defects, which underlines the prospect of using gene therapy in patient care. During the past decade, CRISPR technology has rapidly evolved into a powerful gene editing tool with high fidelity and precision. However, one of the impediments slowing down the clinical translation of CRISPR-based gene therapy concerns the lack of ideal delivery vectors. Extracellular vesicles (EVs) are nano-sized membrane sacs naturally released from nearly all types of cells. Although EVs are secreted for bio-information conveyance among cells or tissues, they have been recognized as superior vectors for drug or gene delivery. Recently, emerging evidence has spotlighted EVs in CRISPR delivery towards cancer treatment. In this review, we briefly introduce the biology and function of the CRISPR system and follow this with a summary of current delivery methods for CRISPR applications. We emphasize the recent progress in EV-mediated CRISPR editing for various cancer types and target genes. The reported strategies for constructing EV-CRISPR vectors, as well as their limitations, are discussed in detail. The review aims to throw light on the clinical potential of engineered EVs and encourage the expansion of our available toolkit to defeat cancer.

Potential Application of Exosomes in Vaccine Development and Delivery

Exosomes are cell-derived components composed of proteins, lipid, genetic information, cytokines, and growth factors. They play a vital role in immune modulation, cell-cell communication, and response to inflammation. Immune modulation has downstream effects on the regeneration of damaged tissue, promoting survival and repair of damaged resident cells, and promoting the tumor microenvironment via growth factors, antigens, and signaling molecules. On top of carrying biological messengers like mRNAs, miRNAs, fragmented DNA, disease antigens, and proteins, exosomes modulate internal cell environments that promote downstream cell signaling pathways to facilitate different disease progression and induce anti-tumoral effects. In this review, we have summarized how vaccines modulate our immune response in the context of cancer and infectious diseases and the potential of exosomes as vaccine delivery vehicles. Both pre-clinical and clinical studies show that exosomes play a decisive role in processes like angiogenesis, prognosis, tumor growth metastasis, stromal cell activation, intercellular communication, maintaining cellular and systematic homeostasis, and antigen-specific T- and B cell responses. This critical review summarizes the advancement of exosome based vaccine development and delivery, and this comprehensive review can be used as a valuable reference for the broader delivery science community.

Dendritic Cell-Based Vaccines Against Cancer: Challenges, Advances and Future Opportunities

As the most potent professional antigen presenting cells, dendritic cells (DCs) have the ability to activate both naive CD4 and CD8 T cells. Recognized for their exceptional ability to cross-present exogenous antigens to prime naive antigen-specific CD8 T cells, DCs play a critical role in generating CD8 T cell immunity, as well as mediating CD8 T cell tolerance to tumor antigens. Despite the ability to potentiate host CD8 T cell-mediated anti-tumor immunity, current DC-based cancer vaccines have not yet achieved the promised success clinically with the exception of FDA-approved Provenge. Interestingly, recent studies have shown that type 1 conventional DCs (cDC1s) play a critical role in cross-priming tumor-specific CD8 T cells and determining the anti-tumor efficacy of cancer immunotherapies including immune checkpoint blockade (ICB). Together with promising clinical results in neoantigen-based cancer vaccines, there is a great need for DC-based vaccines to be further developed and refined either as monotherapies or in combination with other immunotherapies. In this review, we will present a brief review of DC development and function, discuss recent progress, and provide a perspective on future directions to realize the promising potential of DC-based cancer vaccines.

The roles of small extracellular vesicles in cancer and immune regulation and translational potential in cancer therapy

Extracellular vesicles (EVs) facilitate the extracellular transfer of proteins, lipids, and nucleic acids and mediate intercellular communication among multiple cells in the tumour environment. Small extracellular vesicles (sEVs) are defined as EVs range in diameter from approximately 50 to 150 nm. Tumour-derived sEVs (TDsEVs) and immune cell-derived sEVs have significant immunological activities and participate in cancer progression and immune responses. Cancer-specific molecules have been identified on TDsEVs and can function as biomarkers for cancer diagnosis and prognosis, as well as allergens for TDsEVs-based vaccination. Various monocytes, including but not limited to dendritic cells (DCs), B cells, T cells, natural killer (NK) cells, macrophages, and myeloid-derived suppressor cells (MDSCs), secrete sEVs that regulate immune responses in the complex immune network with either protumour or antitumour effects. After engineered modification, sEVs from immune cells and other donor cells can provide improved targeting and biological effects. Combined with their naïve characteristics, these engineered sEVs hold great potential as drug carriers. When used in a variety of cancer therapies, they can adjunctly enhance the safety and antitumor efficacy of multiple therapeutics. In summary, both naïve sEVs in the tumour environment and engineered sEVs with effector cargoes are regarded as showing promising potential for use in cancer diagnostics and therapeutics.

Exosomes carrying immune checkpoints, a promising therapeutic approach in cancer treatment

Exosomes are a subgroup of extracellular vesicles generated by distinct cells. Tumor-derived extracellular vesicles convey immunological checkpoint molecules. TEXs as critical mediators in tumor development, metastasis, and immune escape have recently become the focus of scientific research. Exosomes are involved in the regulation of the immune system. Exosomes interact with target cells in the tumor microenvironment, changing their function based on the cargo they contain. Exosomal immune checkpoints might be exploited to track tumor immune evasion, treatment response, and patient prognosis while enhancing tumor cell proliferation and spread. This review focuses on tumor-derived exosomes, their immunosuppressive effects in mice models, and their role in cancer immunotherapy. Exosomes are being studied as possible cancer vaccines, with numerous uses in tumor immunotherapy. Exosomes can carry chemotherapeutics, siRNA, and monoclonal antibodies. Exosomes produced by macrophages might be used to treat cancer. These and other clinical consequences provide new doors for cancer treatment.

Emerging innovations on exosome-based onco-therapeutics

Exosomes, nano-sized extracellular vesicles for intercellular communications, are gaining rapid momentum as a novel strategy for the diagnosis and therapeutics of a spectrum of diseases including cancers. Secreted by various cell sources, exosomes pertain numerous functionalities from their parental cells and have enhanced stability that enable them with many features favorable for clinical use and commercialization. This paper focuses on the possible roles of exosomes in cancer therapeutics and reviews current exosome-based innovations toward enhanced cancer management and challenges that limit their clinical translation. Importantly, this paper casts insights on how cold atmospheric plasma, an emerging anticancer strategy, may aid in innovations on exosome-based onco-therapeutics toward improved control over cancers.

Extracellular vesicle-mediated immunoregulation in cancer

Extracellular vesicles (EVs) have emerged as immunomodulatory regulators during tumor progression. These small vesicles encapsulate a variety of molecules, including DNA, RNA, and proteins. When EVs come in contact with recipient cells, the EVs transmit various physiological characteristics; for example, proteins on the surface of EVs act as ligands. Immune checkpoint blockade targeting cytotoxic T-lymphocyte-associated antigen 4 (CTLA4), programmed cell death 1 (PD-1) and programmed cell death ligand 1 (PD-L1) has shown promise in a subset of cancer patients. PD-L1 on EVs acts as a key immunomodulator. Suppression of EV secretion enhances the efficacy of immunotherapy using immune checkpoint blockade antibodies. In addition to immune checkpoint blockade therapy, chimeric antigen receptor T (CAR-T) cell therapy has also been used to successfully eliminate cancer cells. Interestingly, CAR-T-cell-derived EVs express CAR on their surface. Compared with CAR-T cells, CAR-expressing EVs do not express PD1, so their antitumor effect cannot be weakened. In this review, we describe the current understanding of EVs in cancer immunity and summarize their crucial roles in immunomodulation.

Recent progress of dendritic cell-derived exosomes (Dex) as an anti-cancer nanovaccine

Although cancer vaccines such as dendritic cell (DC) vaccines and peptide vaccines have become appealing and attractive anticancer immunotherapy options in recent decades, some obstacles have hindered their successful application in the clinical setting. The difficulties associated with the high cost of DC preparation, storage of DC vaccines, tumor-mediated immunosuppressive environment, identification of specific tumor antigens, and high degradation of antigen peptides in vivo limit the clinical application and affect the outcomes of these cancer vaccines. Recently, nanocarriers have been considered as a new approach for vaccine delivery. As biogenic nanocarriers, exosomes are small membrane vesicles secreted by cells that carry various proteins, RNAs, and lipids. More importantly, DC-derived exosomes (Dex) express tumor antigens, MHC molecules, and co-stimulatory molecules on their surface, which trigger the release of antigen-specific CD4⁺ and CD8⁺ T cells. With their membrane structure, Dex can avoid high degradation while ensuring favorable biocompatibility and biosafety in vivo. In addition, Dex can be stored in vitro for a longer period, which facilitates a significant reduction in production costs. Furthermore, they have shown better antitumor efficacy in preclinical studies compared with DC vaccines owing to their higher immunogenicity and stronger resistance to immunosuppressive effects. However, the clinical efficacy of Dex vaccines remains limited. In this review, we aimed to evaluate the efficacy of Dex as an anticancer nanovaccine.

Engineered extracellular vesicles and their mimetics for cancer immunotherapy

Extracellular vesicles (EVs) are heterogeneous membranous vesicles secreted by living cells that are involved in many physiological and pathological processes as intermediaries for intercellular communication and molecular transfer. Recent studies have shown that EVs can regulate the occurrence and development of tumors by transferring proteins, lipids and nucleic acids to immune cells as signaling molecules. As a new diagnostic biomarker and drug delivery system, EVs have broad application prospects in immunotherapy. In addition, the breakthrough of nanotechnology has promoted the development and exploration of engineered EVs for immune-targeted therapy. Herein, we review the uniqueness of EVs in immune regulation and the engineering strategies used for immunotherapy and highlight the logic of their design through typical examples. The present situation and challenges of clinical transformation are discussed, and the development prospects of EVs in immunotherapy are proposed. The goal of this review is to provide new insights into the design of immune-regulatory EVs and expand their application in cancer immunotherapy.

Manufacturing Therapeutic Exosomes: from Bench to Industry

Process of manufacturing therapeutics exosome development for commercialization. The development of exosome treatment starts at the bench, and in order to be commercialized, it goes through the manufacturing, characterization, and formulation stages, production under Good Manufacturing Practice (GMP) conditions for clinical use, and close consultation with regulatory authorities. Exosome, a type of nanoparticles also known as small extracellular vesicles are gaining attention as novel therapeutics for various diseases because of their ability to deliver genetic or bioactive molecules to recipient cells. Although many pharmaceutical companies are gradually developing exosome therapeutics, numerous hurdles remain regarding manufacture of clinical-grade exosomes for therapeutic use. In this mini-review, we will discuss the manufacturing challenges of therapeutic exosomes, including cell line development, upstream cell culture, and downstream purification process. In addition, developing proper formulations for exosome storage and, establishing good manufacturing practice facility for producing therapeutic exosomes remains as challenges for developing clinicalgrade exosomes. However, owing to the lack of consensus regarding the guidelines for manufacturing therapeutic exosomes, close communication between regulators and companies is required for the successful development of exosome therapeutics. This review shares the challenges and perspectives regarding the manufacture and quality control of clinical grade exosomes.

Immune Modulation Using Extracellular Vesicles Encapsulated with MicroRNAs as Novel Drug Delivery Systems

Self-tolerance involves protection from self-reactive B and T cells via negative selection during differentiation, programmed cell death, and inhibition of regulatory T cells. The breakdown of immune tolerance triggers various autoimmune diseases, owing to a lack of distinction between self-antigens and non-self-antigens. Exosomes are non-particles that are approximately 50–130 nm in diameter. Extracellular vesicles can be used for in vivo cell-free transmission to enable intracellular delivery of proteins and nucleic acids, including microRNAs (miRNAs). miRNAs encapsulated in exosomes can regulate the molecular pathways involved in the immune response through post-transcriptional regulation. Herein, we sought to summarize and review the molecular mechanisms whereby exosomal miRNAs modulate the expression of genes involved in the immune response.

Engineering strategies for customizing extracellular vesicle uptake in a therapeutic context

Extracellular vesicles (EVs) are advanced therapeutic strategies that can be used to efficiently treat diseases. Promising features of EVs include their innate therapeutic properties and ability to be engineered as targeted drug delivery systems. However, regulation of EV uptake is one challenge of EV therapy that must be overcome to achieve an efficient therapeutic outcome. Numerous efforts to improve the factors that affect EV uptake include the selection of a cell source, cell cultivation procedure, extraction and purification methods, storage, and administration routes. Limitations of rapid clearance, targeted delivery, and off-targeting of EVs are current challenges that must be circumvented. EV engineering can potentially overcome these limitations and provide an ideal therapeutic use for EVs. In this paper, we intend to discuss traditional strategies and their limitations, and then review recent advances in EV engineering that can be used to customize and control EV uptake for future clinical applications.

Aspects of Biological Replication and Evolution Independent of the Central Dogma: Insights from Protein-Free Vesicular Transformations and Protein-Mediated Membrane Remodeling

Biological membrane remodeling is central to living systems. In spite of serving as “containers” of whole-living systems and functioning as dynamic compartments within living systems, biological membranes still find a “blue collar” treatment compared to the “white collar” nucleic acids and proteins in biology. This may be attributable to the fact that scientific literature on biological membrane remodeling is only 50 years old compared to ~ 150 years of literature on proteins and a little less than 100 years on nucleic acids. However, recently, evidence for symbiotic origins of eukaryotic cells from data only on biological membranes was reported. This, coupled with appreciation of reproducible amphiphilic self-assemblies in aqueous environments (mimicking replication), has already initiated discussions on origins of life beyond nucleic acids and proteins. This work presents a comprehensive compilation and meta-analyses of data on self-assembly and vesicular transformations in biological membranes—starting from model membranes to establishment of Influenza Hemagglutinin-mediated membrane fusion as a prototypical remodeling system to a thorough comparison between enveloped mammalian viruses and cellular vesicles. We show that viral membrane fusion proteins, in addition to obeying “stoichiometry-driven protein folding”, have tighter compositional constraints on their amino acid occurrences than general-structured proteins, regardless of type/class. From the perspective of vesicular assemblies and biological membrane remodeling (with and without proteins) we find that cellular vesicles are quite different from viruses. Finally, we propose that in addition to pre-existing thermodynamic frameworks, kinetic considerations in de novo formation of metastable membrane structures with available “third-party” constituents (including proteins) were not only crucial for origins of life but also continue to offer morphological replication and/or functional mechanisms in modern life forms, independent of the central dogma.

Extracellular Vesicles as an Advanced Delivery Biomaterial for Precision Cancer Immunotherapy

In recent years, cancer immunotherapy has been observed in numerous preclinical and clinical studies for showing benefits. However, due to the unpredictable outcomes and low response rates, novel targeting delivery approaches and modulators are needed for being effective to more broader patient populations and cancer types. Compared to synthetic biomaterials, extracellular vesicles (EVs) specifically open a new avenue for improving the efficacy of cancer immunotherapy by offering targeted and site-specific immunity modulation. In this review, the molecular understanding of EV cargos and surface receptors, which underpin cell targeting specificity and precisely modulating immunogenicity, are discussed. Unique properties of EVs are reviewed in terms of their surface markers, intravesicular contents, intrinsic immunity modulatory functions, and pharmacodynamic behavior in vivo with tumor tissue models, highlighting key indications of improved precision cancer immunotherapy. Novel molecular engineered strategies for reprogramming and directing cancer immunotherapeutics, and their unique challenges are also discussed to illuminate EV's future potential as a cancer immunotherapeutic biomaterial.

Immune cell-derived small extracellular vesicles in cancer treatment

Small extracellular vesicles (sEVs) secreted by most cells carry bioactive macromolecules including proteins, lipids, and nucleic acids for intercellular communication. Given that some immune cell-derived sEVs exhibit anti-cancer properties, these sEVs have received scientific attention for the development of novel anti-cancer immunotherapeutic agents. In this paper, we reviewed the latest advances concerning the biological roles of immune cell-derived sEVs for cancer therapy. sEVs derived from immune cells including dendritic cells (DCs), T cells, natural-killer (NK) cells, and macrophages are good candidates for sEV-based cancer therapy. Besides their role of cancer vaccines, DC-shed sEVs activated cytotoxic lymphocytes and killed tumor cells. sEVs isolated from NK cells and chimeric antigen receptor (CAR) T cells exhibited cytotoxicity against cancer cells. sEVs derived from CD8⁺ T and CD4⁺ T cells inhibited cancer-associated cells in tumor microenvironment (TME) and activated B cells, respectively. M1-macrophage-derived sEVs induced M2 to M1 repolarization and also created a pro-inflammatory environment. Hence, these sEVs, via mono or combination therapy, could be considered in the treatment of cancer patients in the future. In addition, sEVs derived from cytokine-stimulated immune cells or sEV engineering could improve their anti-tumor potency.

An efficient and safe MUC1-dendritic cell-derived exosome conjugate vaccine elicits potent cellular and humoral immunity and tumor inhibition in vivo

Antitumor vaccines are a promising strategy for preventing or treating cancers by eliciting antitumor immune responses and inducing protective immunity against specific antigens expressed on tumor cells. Vaccine formulations that enhance the humoral and cellular immune responses of vaccine candidates would be highly beneficial but are still limited. Here we developed an antitumor vaccine candidate by conjugating a MUC1 glycopeptide antigen to dendritic cell-derived exosomes (Dex). In vivo, the MUC1-Dex construct induced high MUC1-specific IgG antibody titers with strong binding affinities for MUC1-positive tumor cells and promoted cytokine secretion. Moreover, CD8⁺ T cells from immunized mice exhibited strong cytotoxicity against MUC1-positive tumor cells. Importantly, in both preventative and therapeutic tumor-bearing mouse models, the construct inhibited tumor growth and prolonged survival. Collectively, these results demonstrate that Dex is a promising vaccine carrier that can be used as adjuvant to enhance the immunological efficacy of tumor vaccines. STATEMENT OF SIGNIFICANCE.

Immune Cell-Derived Extracellular Vesicles – New Strategies in Cancer Immunotherapy

Immune cell-derived extracellular vesicles (EVs) have increasingly become the focus of research due to their unique characteristics and bioinspired applications. They are lipid bilayer membrane nanosized vesicles harboring a range of immune cell-derived surface receptors and effector molecules from parental cells. Immune cell-derived EVs are important mediators of intercellular communication that regulate specific mechanisms of adaptive and innate immune responses. However, the mechanisms underlying the antitumor effects of EVs are still being explored. Importantly, immune cell-derived EVs have some unique features, including accessibility, storage, ability to pass through blood-brain and blood-tumor barriers, and loading of various effector molecules. Immune cell-derived EVs have been directly applied or engineered as potent antitumor vaccines or for the diagnosis of clinical diseases. More research applications involving genetic engineering, membrane engineering, and cargo delivery strategies have improved the treatment efficacy of EVs. Immune cell-derived EV-based therapies are expected to become a separate technique or to complement immunotherapy, radiotherapy, chemotherapy and other therapeutic modalities. This review aims to provide a comprehensive overview of the characteristics and functions of immune cell-derived EVs derived from adaptive (CD4⁺ T, CD8⁺ T and B cells) and innate immune cells (macrophages, NK cells, DCs, and neutrophils) and discuss emerging therapeutic opportunities and prospects in cancer treatment.

Nanovesicles released by OKT3 hybridoma express fully active antibodies

Recent findings have shown that nanovesicles preparations from either primary immune cells culture supernatants or plasma contain immunoglobulins, suggesting that a natural way of antibody production may be through exosome release. To verify this hypothesis, we used the OKT3 hybridoma clone, which produces a murine IgG2a monoclonal antibody used to reduce rejection in patients undergoing organ transplantation. We showed exosome-associated immunoglobulins in hybridoma supernatants, by Western blot, nanoscale flow cytometry and immunocapture-based ELISA. The OKT3-exo was also being able to trigger cytokines production in both CD4 and CD8 T cells. These results show that nanovesicles contain immunoglobulin and could be used for immunotherapy. These data could lead to a new approach to improve the effectiveness of therapeutic antibodies by exploiting their natural property to be expressed on nanovesicle membrane, that probably render them more stable and as a consequence more capable to interact with their specific ligand in the best way.

Development of surface engineered antigenic exosomes as vaccines for respiratory syncytial virus

Respiratory syncytial virus (RSV) is one of the main pathogens associated with lower respiratory tract infections in infants and young children worldwide. Exosomes secreted by antigen presenting cells (APCs) can elicit immune responses by carrying major histocompatibility complex (MHC) class I molecules complexed with antigenic peptides and other co-stimulating factors. Therefore, we developed novel immunomagnetic nanographene particles to sequentially isolate, surface engineer, and release intact dendritic cell (DC) exosomes for use as a potential vaccine platform against RSV. The H-2Db-restricted, immunodominant peptides from RSV (M187-195 and NS161-75) were introduced to MHC-I on DC-derived exosomes to express peptide/MHC-I (pMHC-I) complexes. A mouse model of RSV infection was used to define the immunogenicity of surface engineered exosomes for activating virus-specific immune responses. Ex vivo assays demonstrated that engineered exosomes carrying RSV-specific peptides can elicit interferon-gamma (IFN-γ) production by virus-specific CD8+ T cells isolated from RSV-infected C57BL/6 mice. In vivo assays demonstrated that subcutaneous administration of both M187-195 and NS161-75 engineered exosomes to mice, with or without additional adjuvant, appeared safe and well tolerated, however, did not prime antigen-specific CD8+ T cell responses. Surface engineered exosomes are immunogenic and promising for further development as a vaccine platform.

Gift bags from the sentinel cells of the immune system: The diverse role of dendritic cell-derived extracellular vesicles

Dendritic cells (DCs) are professional APCs of the immune system that continuously sample their environment and function to stimulate an adaptive immune response by initiating Ag-specific immunity or tolerance. Extracellular vesicles (EVs), small membrane-bound structures, are released from DCs and have been discovered to harbor functional peptide-MHC complexes, T cell costimulatory molecules, and other molecules essential for Ag presentation, immune cell regulation, and stimulating immune responses. As such, DC-derived EVs are being explored as potential immunotherapeutic agents. DC-derived EVs have also been implicated to function as a trafficking mechanism of infectious particles aiding viral propagation. This review will explore the unique features that enable DC-derived EVs to regulate immune responses and interact with recipient cells, their roles within Ag-presentation and disease settings, as well as speculating on a potential immunological role of apoptotic DC-derived EVs.

The Role of Melanoma Cell-Derived Exosomes (MTEX) and Photodynamic Therapy (PDT) within a Tumor Microenvironment

Photodynamic Therapy (PDT), an unconventional cancer therapy with optimistic desirable effects, utilizes the delivery of a photosensitizer (PS) that is activated by light at a particular wavelength and inducing oxidative cytotoxic damage of a tumor and its surrounding vasculature. Deeper seated tumors such as internally metastasized melanomas are more difficult to treat with PDT as the penetration of laser light to those sites is less. Limitations in targeting melanomas can also be attributed to melanin pigments that hinder laser light from reaching targeted sites. Exosomes serve as naturally occurring nanoparticles that can be re-assembled with PSs, improving targeted cellular absorption of photosensitizing agents during PDT. Additionally, studies indicate that exosomes released from PDT-treated tumor cells play a critical role in mediating anti-tumor immune responses. This review collates the role of Melanoma Cell-Derived Exosomes (MTEX) in immune response mediation and metastasis. Tumor Cell-Derived Exosomes (TEX) post PDT treatment are also reviewed, as well as the effects of exosomes as carriers of photosensitizers and delivery systems for PDT. The understanding and research on the role of melanoma exosomes induced by Photodynamic Therapy and their tumor microenvironment will assist in future research in treatment prospects and implications.

Harnessing EV communication to restore antitumor immunity

Restoring effective anti-tumor immune responses to cure cancer is a promising strategy, but challenging to achieve due to the intricate crosstalk between tumor and immune cells. While it is established that tumor cells acquire traits to escape immune recognition, the involvement of extracellular vesicles (EVs) in curbing immune cell activation is rapidly emerging. By assisting cancer cells in spreading immunomodulatory signals in the form of (glyco)proteins, lipids, nucleic acids and metabolic regulators, EVs recently emerged as versatile mediators of immune suppression. Blocking their action might reactivate immune cell function and natural antitumor immune responses. Alternatively, EV communication may be exploited to boost anti-tumor immunity. Indeed, novel insights into EV biology paved the way for efficient ex vivo production of 'rationally engineered' EVs that function as potent antitumor vaccines or carry out specific functional tasks. In this review we discuss the latest findings on immune regulation by cancer EVs and explore how EV-mediated communication can be either targeted or harnessed to restore immunity as a means for cancer therapy.