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

Engineered Cancer Nanovaccines: A New Frontier in Cancer Therapy

Vaccinations are essential for preventing and treating disease, especially cancer nanovaccines, which have gained considerable interest recently for their strong anti-tumor immune capabilities. Vaccines can prompt the immune system to generate antibodies and activate various immune cells, leading to a response against tumor tissues and reducing the negative effects and recurrence risks of traditional chemotherapy and surgery. To enhance the flexibility and targeting of vaccines, nanovaccines utilize nanotechnology to encapsulate or carry antigens at the nanoscale level, enabling more controlled and precise drug delivery to enhance immune responses. Cancer nanovaccines function by encapsulating tumor-specific antigens or tumor-associated antigens within nanomaterials. The small size of these nanomaterials allows for precise targeting of T cells, dendritic cells, or cancer cells, thereby eliciting a more potent anti-tumor response. In this paper, we focus on the classification of carriers for cancer nanovaccines, the roles of different target cells, and clinically tested cancer nanovaccines, discussing strategies for effectively inducing cytotoxic T lymphocytes responses and optimizing antigen presentation, while also looking ahead to the translational challenges of moving from animal experiments to clinical trials.

Extracellular vesicle autoantibodies

Autoantibodies are immunoglobulin proteins produced by autoreactive B cells responding to self-antigens. Extracellular vesicles (EVs) are membranous structures released by almost all types of cells and extensively distributed in various biological fluids. Studies have indicated that EVs loaded with self-antigens not only play important roles in antigen presentation and autoantibody production but can also form functional immune complexes with autoantibodies (termed EV autoantibodies). While numerous papers have summarized the production and function of pathogenic autoantibodies in diseases, especially autoimmune diseases, reviews on EV autoantibodies are rare. In this review, we outline the existing knowledge about EVs, autoantibodies, and EV antigens, highlighting the formation of EV autoantibodies and their functions in autoimmune diseases and cancers. In conclusion, EV autoantibodies may be involved in the occurrence of disease(s) and also serve as potential non-invasive markers that could help in the diagnosis and/or prognosis of disease. Additional studies designed to define in more detail the molecular characteristics of EV autoantibodies and their contribution to disease are recommended.

Advancements in melanoma immunotherapy: the emergence of Extracellular Vesicle Vaccines

Malignant melanoma represents a particularly aggressive type of skin cancer, originating from the pathological transformation of melanocytes. While conventional interventions such as surgical resection, chemotherapy, and radiation therapy are available, their non-specificity and collateral damage to normal cells has shifted the focus towards immunotherapy as a notable approach. Extracellular vesicles (EVs) are naturally occurring transporters, and are capable of delivering tumor-specific antigens and directly engaging in the immune response. Multiple types of EVs have emerged as promising platforms for melanoma vaccination. The effectiveness of EV-based melanoma vaccines manifests their ability to potentiate the immune response, particularly by activating dendritic cells (DCs) and CD8+ T lymphocytes, through engineering a synergy of antigen presentation and targeted delivery. Here, this review mainly focuses on the construction strategies for EV vaccines from various sources, their effects, and immunological mechanisms in treating melanoma, as well as the shortcomings and future perspectives in this field. These findings will provide novel insights into the innovative exploitation of EV-based vaccines for melanoma immune therapy.

Cancer Nanovaccines: Nanomaterials and Clinical Perspectives

Cancer nanovaccines represent a promising frontier in cancer immunotherapy, utilizing nanotechnology to augment traditional vaccine efficacy. This review comprehensively examines the current state-of-the-art in cancer nanovaccine development, elucidating innovative strategies and technologies employed in their design. It explores both preclinical and clinical advancements, emphasizing key studies demonstrating their potential to elicit robust anti-tumor immune responses. The study encompasses various facets, including integrating biomaterial-based nanocarriers for antigen delivery, adjuvant selection, and the impact of nanoscale properties on vaccine performance. Detailed insights into the complex interplay between the tumor microenvironment and nanovaccine responses are provided, highlighting challenges and opportunities in optimizing therapeutic outcomes. Additionally, the study presents a thorough analysis of ongoing clinical trials, presenting a snapshot of the current clinical landscape. By curating the latest scientific findings and clinical developments, this study aims to serve as a comprehensive resource for researchers and clinicians engaged in advancing cancer immunotherapy. Integrating nanotechnology into vaccine design holds immense promise for revolutionizing cancer treatment paradigms, and this review provides a timely update on the evolving landscape of cancer nanovaccines.

Extracellular vesicles at the crossroad between cancer progression and immunotherapy: focus on dendritic cells

Extracellular vesicles (EVs) are nanosized heat-stable vesicles released by virtually all cells in the body, including tumor cells and tumor-infiltrating dendritic cells (DCs). By carrying molecules from originating cells, EVs work as cell-to-cell communicators in both homeostasis and cancer but may also represent valuable therapeutic and diagnostic tools. This review focuses on the role of tumor-derived EVs (TEVs) in the modulation of DC functions and on the therapeutic potential of both tumor- and DC-derived EVs in the context of immunotherapy and DC-based vaccine design. TEVs were originally characterized for their capability to transfer tumor antigens to DCs but are currently regarded as mainly immunosuppressive because of the expression of DC-inhibiting molecules such as PD-L1, HLA-G, PGE2 and others. However, TEVs may still represent a privileged system to deliver antigenic material to DCs upon appropriate engineering to reduce their immunosuppressive cargo or increase immunogenicity. DC-derived EVs are more promising than tumor-derived EVs since they expose antigen-loaded MHC, costimulatory molecules and NK cell-activating ligands in the absence of an immunosuppressive cargo. Moreover, DC-derived EVs possess several advantages as compared to cell-based drugs such as a higher antigen/MHC concentration and ease of manipulation and a lower sensitivity to immunosuppressive microenvironments. Preclinical models showed that DC-derived EVs efficiently activate tumor-specific NK and T cell responses either directly or indirectly by transferring antigens to tumor-infiltrating DCs. By contrast, however, phase I and II trials showed a limited clinical efficacy of EV-based anticancer vaccines. We discuss that the future of EV-based therapy depends on our capability to overcome major challenges such as a still incomplete understanding of their biology and pharmacokinetic and the lack of standardized methods for high-throughput isolation and purification. Despite this, EVs remain in the limelight as candidates for cancer immunotherapy which may outmatch cell-based strategies in the fullness of their time.

Engineered dendritic cells-derived exosomes harboring HIV-1 Nefmut-Tat fusion protein and heat shock protein 70: A promising HIV-1 safe vaccine candidate

Antigen presenting cells (APCs)-derived exosomes are nano-vesicles that can induce antigen-specific T cell responses, and possess therapeutic effects in clinical settings. Moreover, dendritic cells (DCs)-based vaccines have been developed to combat human immunodeficiency virus-1 (HIV-1) infection in preclinical and clinical trials. We investigated the immunostimulatory effects (B- and T-cells activities) of DCs- and exosomes-based vaccine constructs harboring HIV-1 Nefmut-Tat fusion protein as an antigen candidate and heat shock protein 70 (Hsp70) as an adjuvant in mice. The modified DCs and engineered exosomes harboring Nefmut-Tat protein or Hsp70 were prepared using lentiviral vectors compared to electroporation, characterized and evaluated by in vitro and in vivo immunological tests. Our data indicated that the engineered exosomes induced high levels of total IgG, IgG2a, IFN-γ, TNF-α and Granzyme B. Moreover, co-injection of exosomes harboring Hsp70 could significantly increase the secretion of antibodies, cytokines and Granzyme B. The highest levels of IFN-γ and TNF-α were observed in exosomes harboring Nefmut-Tat combined with exosomes harboring Hsp70 (Exo-Nefmut-Tat + Exo-Hsp70) regimen after single-cycle replicable (SCR) HIV-1 exposure. Generally, Exo-Nefmut-Tat + Exo-Hsp70 regimen can be considered as a promising safe vaccine candidate due to high T-cells (Th1 and CTL) activity and its maintenance against SCR HIV-1 exposure.

Extracellular vesicles derived from immune cells: Role in tumor therapy

Extracellular vesicles (EVs), which have a lipid nano-sized structure, are known to contain the active components of parental cells and play a crucial role in intercellular communication. The progression and metastasis of tumors are influenced by EVs derived from immune cells, which can simultaneously stimulate and suppress immune responses. In the past few decades, there has been a considerable focus on EVs due to their potential in various areas such as the development of vaccines, delivering drugs, making engineered modifications, and serving as biomarkers for diagnosis and prognosis. This review focuses on the substance information present in EVs derived from innate and adaptive immune cells, their effects on the immune system, and their applications in cancer treatment. While there are still challenges to overcome, it is important to explore the composition of immune cells released vesicles and their potential therapeutic role in tumor therapy. The review also highlights the current limitations and future prospects in utilizing EVs for treatment purposes.

Extracellular vesicles and cancer stemness in hepatocellular carcinoma - is there a link?

Hepatocellular carcinoma (HCC) is a highly aggressive malignancy, with high recurrence rates and notorious resistance to conventional chemotherapy. Cancer stemness refers to the stem-cell-like phenotype of cancer cells and has been recognized to play important roles in different aspects of hepatocarcinogenesis. Small extracellular vesicles (sEVs) are small membranous particles secreted by cells that can transfer bioactive molecules, such as nucleic acids, proteins, lipids, and metabolites, to neighboring or distant cells. Recent studies have highlighted the role of sEVs in modulating different aspects of the cancer stemness properties of HCC. Furthermore, sEVs derived from diverse cellular sources, such as cancer cells, stromal cells, and immune cells, contribute to the maintenance of the cancer stemness phenotype in HCC. Through cargo transfer, specific signaling pathways are activated within the recipient cells, thus promoting the stemness properties. Additionally, sEVs can govern the secretion of growth factors from non-cancer cells to further maintain their stemness features. Clinically, plasma sEVs may hold promise as potential biomarkers for HCC diagnosis and treatment prediction. Understanding the underlying mechanisms by which sEVs promote cancer stemness in HCC is crucial, as targeting sEV-mediated communication may offer novel strategies in treatment and improve patient outcome.

Exosomes in Glioma: Unraveling Their Roles in Progression, Diagnosis, and Therapy

Gliomas, the most prevalent primary malignant brain tumors, present a challenging prognosis even after undergoing surgery, radiation, and chemotherapy. Exosomes, nano-sized extracellular vesicles secreted by various cells, play a pivotal role in glioma progression and contribute to resistance against chemotherapy and radiotherapy by facilitating the transportation of biological molecules and promoting intercellular communication within the tumor microenvironment. Moreover, exosomes exhibit the remarkable ability to traverse the blood-brain barrier, positioning them as potent carriers for therapeutic delivery. These attributes hold promise for enhancing glioma diagnosis, prognosis, and treatment. Recent years have witnessed significant advancements in exosome research within the realm of tumors. In this article, we primarily focus on elucidating the role of exosomes in glioma development, highlighting the latest breakthroughs in therapeutic and diagnostic approaches, and outlining prospective directions for future research.

Tumorigenic and tumoricidal properties of exosomes in cancers; a forward look

In recent decades, emerging data have highlighted the critical role of extracellular vesicles (EVs), especially (exosomes) Exos, in the progression and development of several cancer types. These nano-sized vesicles are released by different cell lineages within the cancer niche and maintain a suitable platform for the interchange of various signaling molecules in a paracrine manner. Based on several studies, Exos can transfer oncogenic factors to other cells, and alter the activity of immune cells, and tumor microenvironment, leading to the expansion of tumor cells and metastasis to the remote sites. It has been indicated that the cell-to-cell crosstalk is so complicated and a wide array of factors are involved in this process. How and by which mechanisms Exos can regulate the behavior of tumor cells and non-cancer cells is at the center of debate. Here, we scrutinize the molecular mechanisms involved in the oncogenic behavior of Exos released by different cell lineages of tumor parenchyma. Besides, tumoricidal properties of Exos from various stem cell (SC) types are discussed in detail.

Global trends in tumor microenvironment-related research on tumor vaccine: a review and bibliometric analysis

Background

Tumor vaccines have become crucial in cancer immunotherapy, but, only a limited number of phase III clinical trials have demonstrated clinical efficacy. The crux of this issue is the inability of tumor vaccines to effectively harmonize the tumor microenvironment with its intricate interplay. One factor that can hinder the effectiveness of vaccines is the natural immunosuppressive element present in the tumor microenvironment. This element can lead to low rates of T-cell response specific to antigens and the development of acquired resistance. Conversely, anticancer vaccines alter the tumor microenvironment in conflicting manners, inducing both immune activation and immunological evasion. Hence, comprehending the correlation between tumor vaccines and the tumor microenvironment would establish a foundation for forthcoming tumor treatment.

Objective

Our review explores the realm of research pertaining to tumor vaccinations and the tumor microenvironment. Our objective is to investigate the correlation between tumor vaccines and the tumor microenvironment within this domain. We then focus our review on the dominant international paradigms in this research field and visually illustrates the historical progression and emergent patterns observed in the past.

Methods

From January 1, 1999 to February 7, 2023, 1420 articles on the interplay between tumor vaccines and the tumor microenvironment were published, according to The Clarivate Web of Science (WOS) database used in our review. A bibliometric review was designed for this collection and consisted of an evaluation. The evaluation encompassed various discernible attributes, including the year of publication, the journals in which the articles were published, the authors involved, the affiliated institutions, the geographical locations of the institutions, the references cited, and the keywords employed.

Results

Between the years 1999 and 2022, publications saw a significant increase, from 3 to 265 annually. With 72 papers published, Frontiers in Immunology had the most manuscripts published. The Cancer Research publication garnered the highest number of citations, amounting to 2874 citations. The United States exerts significant dominance in the subject, with the National Cancer Institute being recognized as a prominent institution in terms of both productivity and influence. Furthermore, Elizabeth M. Jaffee was recognized as the field's most prolific and influential author with 24 publications and 1,756 citations. The co-occurrence cluster analysis was conducted on the top 197 keywords, resulting in the identification of five distinct clusters. The most recent high-frequency keywords, namely immune therapy, dendritic cell, tumor microenvironment, cancer, and vaccine, signify the emerging frontiers in the interaction between tumor vaccines and the tumor microenvironment.

Conclusion

Our review uncovers insights into contemporary trends, global patterns of collaboration, fundamental knowledge, research areas of high interest, and emerging frontiers in the field of TME-targeted vaccines.

Exosome-based delivery strategies for tumor therapy: an update on modification, loading, and clinical application

Malignancy is a major public health problem and among the leading lethal diseases worldwide. Although the current tumor treatment methods have therapeutic effect to a certain extent, they still have some shortcomings such as poor water solubility, short half-life, local and systemic toxicity. Therefore, how to deliver therapeutic agent so as to realize safe and effective anti-tumor therapy become a problem urgently to be solved in this field. As a medium of information exchange and material transport between cells, exosomes are considered to be a promising drug delivery carrier due to their nano-size, good biocompatibility, natural targeting, and easy modification. In this review, we summarize recent advances in the isolation, identification, drug loading, and modification of exosomes as drug carriers for tumor therapy alongside their application in tumor therapy. Basic knowledge of exosomes, such as their biogenesis, sources, and characterization methods, is also introduced herein. In addition, challenges related to the use of exosomes as drug delivery vehicles are discussed, along with future trends. This review provides a scientific basis for the application of exosome delivery systems in oncological therapy.

Cell membrane-based biomimetic technology for cancer phototherapy: Mechanisms, recent advances and perspectives

Despite significant advances in medical technology and antitumour treatments, the diagnosis and treatment of tumours have undergone remarkable transformations. Noninvasive phototherapy methods, such as photodynamic therapy (PDT) and photothermal therapy (PTT), have gained significant interest in antitumour medicine. However, traditional photosensitisers or photothermal agents face challenges like immune system recognition, rapid clearance from the bloodstream, limited tumour accumulation, and phototoxicity concerns. Researchers combine photosensitisers or photothermal agents with natural cell membranes to overcome these obstacles to create a nano biomimetic therapeutic platform. When used to coat nanoparticles, red blood cells, platelets, cancer cells, macrophages, lymphocytes, and bacterial outer membranes could provide prolonged circulation, tumour targeting, immune stimulation, or antigenicity. This article covers the principles of cellular membrane biomimetic nanotechnology and phototherapy, along with recent advancements in applying nano biomimetic technology to PDT, PTT, PCT, and combined diagnosis and treatment. Furthermore, the challenges and issues of using nano biomimetic nanoparticles in phototherapy are discussed. STATEMENT OF SIGNIFICANCE: Currently, there has been significant progress in the field of cell membrane biomimetic technology. Researchers are exploring its potential application in tumor diagnosis and treatment through phototherapy. Scholars have conducted extensive research on combining cell membrane technology and phototherapy in anticancer diagnosis and treatment. This review aims to highlight the mechanisms of phototherapy and the latest advancements in single phototherapy (PTT, PDT) and combination phototherapy (PCT, PRT, and PIT), as well as diagnostic approaches. The review provides an overview of various cell membrane technologies, including RBC membranes, platelet membranes, macrophage cell membranes, tumour cell membranes, bacterial membranes, hybrid membranes, and their potential for anticancer applications under phototherapy. Lastly, the review discusses the challenges and future directions in this field.

Biology and function of exosomes in tumor immunotherapy

Exosomes are nano-scale extracellular vesicles that are found widely in various biological fluids. As messengers, exosomes deliver characteristic biological information from donor cells, facilitating their accumulation and subsequent transfer of information to tumor immune cells. Immunotherapy is a cutting-edge strategy for cancer therapy, but it has not yet reached its full potential owing to severe side effects and limited efficacy. Exosomes possess antigens and immunostimulatory molecules and can serve as cell-free vaccines to induce antitumor immunity. In addition, given their stability, low immunogenicity, and targeting ability, exosomes represent ideal drug delivery systems in tumor immunotherapy by delivering cargoes, including non-coding ribonucleic acids (RNAs), membrane proteins, chemotherapeutic agents, and immune cell death inducers. Exosomes can also be engineered to precisely target tumor cells. However, as a rising star in tumor immunotherapy, exosomes are also impeded by some challenges, including the lack of uniform technical standards for their isolation and purification, the need to improve exosomal cargo loading for efficient exosome delivery, and the expansion of clinical trials, which are currently in their infancy. Long-term, multi-center, and large-scale clinical trials are needed to evaluate the performance of exosomes in the future. Nonetheless, exosomes have demonstrated encouraging performance in tumor immunotherapy. In this review, we summarize the potential and challenges of exosomes in tumor immunotherapy, with the aim to shed light on exosomes as new-era tumor immunotherapy tools.

Immune cell-derived exosomes as promising tools for cancer therapy

Exosomes are nanoscale vesicles with a size of 30-150 nm secreted by living cells. They are vital players in cellular communication as they can transport proteins, nucleic acids, lipids, and etc. Immune cell-derived exosomes (imEXOs) have great potential for tumor therapy because they have many of the same functions as their parent cells. Especially, imEXOs display unique constitutive characteristics that are directly involved in tumor therapy. Herein, we begin by the biogenesis, preparation, characterization and cargo loading strategies of imEXOs. Next, we focus on therapeutic potentials of imEXOs from different kinds of immune cells against cancer from preclinical and clinical studies. Finally, we discuss advantages of engineered imEXOs and potential risks of imEXOs in cancer treatment. The advantages of engineered imEXOs are highlighted, including selective killing effect, effective tumor targeting, effective lymph node targeting, immune activation and regulation, and good biosafety.

Advances and prospects of tumor immunotherapy mediated by immune cell-derived biomimetic metal-organic frameworks

The clinical translational success of nanomedicine and immunotherapy has already proved the immense potential in the field of nanotechnology and immunization. However, the development of nanomedicine is confronted with challenges such as potential toxicity and unclear nano-bio interactions. The efficacy of immunotherapy is limited to only a few groups. Combining immunotherapy with nanomedicine for multi-modal treatment effectively compensates for the limitations of the above single therapy. Immune cell membrane camouflaged metal-organic frameworks (ICM-MOFs) have emerged as a simple yet promising multimodal treatment strategy that possess multifunctional nanoscale properties and exhibit immune cell-like behaviors of stealth, targeting and immunomodulation. Here, we comprehensively discuss the latest advancements in ICM-MOFs, with a focus on the challenges of mono-immunotherapy, the superiority of biomimetic coating for MOF functionalization, preparation methods, related action mechanisms and biomedical applications. Finally, we address the challenges and prospects for clinical translation.

The Potential of Dendritic Cell Subsets in the Development of Personalized Immunotherapy for Cancer Treatment

Since the discovery of dendritic cells (DCs) in 1973 by Ralph Steinman, a tremendous amount of knowledge regarding these innate immunity cells has been accumulating. Their role in regulating both innate and adaptive immune processes is gradually being uncovered. DCs are proficient antigen-presenting cells capable of activating naive T-lymphocytes to initiate and generate effective anti-tumor responses. Although DC-based immunotherapy has not yielded significant results, the substantial number of ongoing clinical trials underscores the relevance of DC vaccines, particularly as adjunctive therapy or in combination with other treatment options. This review presents an overview of current knowledge regarding human DCs, their classification, and the functions of distinct DC populations. The stepwise process of developing therapeutic DC vaccines to treat oncological diseases is discussed, along with speculation on the potential of combined therapy approaches and the role of DC vaccines in modern immunotherapy.

Exosomes as a modulator of immune resistance in human cancers

In the tumor microenvironment (TME), exosomes secreted by cells form interactive networks between the tumor cells and immune cells, thereby regulating immune signaling cascades in the TME. As key messengers of cell-to-cell communication in the TME, exosomes not only take charge of tumor cell antigen presentation to the immune cells, but also regulate the activities of immune cells, inhibit immune function, and, especially, promote immune resistance, all of which affects the therapeutic outcomes of tumors. Exosomes, which are small-sized vesicles, possess some remarkable advantages, including strong biological activity, a lack of immunogenicity and toxicity, and a strong targeting ability. Based on these characteristics, research on exosomes as biomarkers or carriers of tumor therapeutic drugs has become a research hotspot in related fields. This review describes the role of exosomes in cell communications in the TME, summarizes the effectiveness of exosome-based immunotherapy in overcoming immune resistance in cancer treatment, and systematically summarizes and discusses the characteristics of exosomes from different cell sources. Furthermore, the prospects and challenges of exosome-related therapies are discussed.

Bidirectional crosstalk between the peripheral nervous system and lymphoid tissues/organs

The central nervous system (CNS) influences the immune system generally by regulating the systemic concentration of humoral substances (e.g., cortisol and epinephrine), whereas the peripheral nervous system (PNS) communicates specifically with the immune system according to local interactions/connections. An imbalance between the components of the PNS might contribute to pathogenesis and the further development of certain diseases. In this review, we have explored the "thread" (hardwiring) of the connections between the immune system (e.g., primary/secondary/tertiary lymphoid tissues/organs) and PNS (e.g., sensory, sympathetic, parasympathetic, and enteric nervous systems (ENS)) in health and disease in vitro and in vivo. Neuroimmune cell units provide an anatomical and physiological basis for bidirectional crosstalk between the PNS and the immune system in peripheral tissues, including lymphoid tissues and organs. These neuroimmune interactions/modulation studies might greatly contribute to a better understanding of the mechanisms through which the PNS possibly affects cellular and humoral-mediated immune responses or vice versa in health and diseases. Physical, chemical, pharmacological, and other manipulations of these neuroimmune interactions should bring about the development of practical therapeutic applications for certain neurological, neuroimmunological, infectious, inflammatory, and immunological disorders/diseases.

Tumor vaccine based on extracellular vesicles derived from γδ-T cells exerts dual antitumor activities

γδ-T cells are innate-like T cells with dual antitumor activities. They can directly eradicate tumor cells and function as immunostimulatory cells to promote antitumor immunity. Previous studies have demonstrated that small extracellular vesicles (EVs) derived from γδ-T cells (γδ-T-EVs) inherited the dual antitumor activities from their parental cells. However, it remains unknown whether γδ-T-EVs can be designed as tumors vaccine to improve therapeutic efficacy. Here, we found that γδ-T-EVs had immune adjuvant effects on antigen-presenting cells, as revealed by enhanced expression of antigen-presenting and co-stimulatory molecules, secretion of pro-inflammatory cytokines and antigen-presenting ability of DCs after γδ-T-EVs treatment. The γδ-T-EVs-based vaccine was designed by loading tumor-associated antigens (TAAs) into γδ-T-EVs. Compared with γδ-T-EVs, the γδ-T-EVs-based vaccine effectively promoted more tumor-specific T-cell responses. In addition, the vaccine regimen preserved direct antitumor effects and induced tumor cell apoptosis. Interestingly, the allogeneic γδ-T-EVs-based vaccine showed comparable preventive and therapeutic antitumor effects to their autologous counterparts, indicating a better way of centralization and standardization in clinical practice. Furthermore, the allogeneic γδ-T-EVs-based vaccine displayed advantages over the DC-EVs-based vaccine through their dual antitumor activities. This study provides a proof-of-concept for using the allogeneic γδ-T-EVs-based vaccine in cancer control.

Dendritic Cell Vaccines: A Shift from Conventional Approach to New Generations

In the emerging era of cancer immunotherapy, immune checkpoint blockades (ICBs) and adoptive cell transfer therapies (ACTs) have gained significant attention. However, their therapeutic efficacies are limited due to the presence of cold type tumors, immunosuppressive tumor microenvironment, and immune-related side effects. On the other hand, dendritic cell (DC)-based vaccines have been suggested as a new cancer immunotherapy regimen that can address the limitations encountered by ICBs and ACTs. Despite the success of the first generation of DC-based vaccines, represented by the first FDA-approved DC-based therapeutic cancer vaccine Provenge, several challenges remain unsolved. Therefore, new DC vaccine strategies have been actively investigated. This review addresses the limitations of the currently most adopted classical DC vaccine and evaluates new generations of DC vaccines in detail, including biomaterial-based, immunogenic cell death-inducing, mRNA-pulsed, DC small extracellular vesicle (sEV)-based, and tumor sEV-based DC vaccines. These innovative DC vaccines are envisioned to provide a significant breakthrough in cancer immunotherapy landscape and are expected to be supported by further preclinical and clinical studies.

Natural killer cell-derived exosomes for cancer immunotherapy: innovative therapeutics art

Chimeric antigen receptor natural killer cells (CAR-NK) promote off-the-shelf cellular therapy for solid tumors and malignancy.However,, the development of CAR-NK is due to their immune surveillance uncertainty and cytotoxicity challenge was restricted. Natural killer cell-derived exosome (NK-Exo) combine crucial targeted cellular therapies of NK cell therapies with unique non-toxic Exo as a self-origin shuttle against cancer immunotherapy. This review study covers cytokines, adoptive (autologous and allogenic) NK immunotherapy, stimulatory and regulatory functions, and cell-free derivatives from NK cells. The future path of NK-Exo cytotoxicity and anti-tumor activity with considering non-caspase-independent/dependent apoptosis and Fas/FasL pathway in cancer immunotherapy. Finally, the significance and implication of NK-Exo therapeutics through combination therapy and the development of emerging approaches for the purification and delivery NK-Exo to severe immune and tumor cells and tissues were discussed in detail.

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.

Mesenchymal stem cells, as glioma exosomal immunosuppressive signal multipliers, enhance MDSCs immunosuppressive activity through the miR-21/SP1/DNMT1 positive feedback loop

BACKGROUND

The immunosuppressive microenvironment in glioma induces immunotherapy resistance and is associated with poor prognosis. Glioma-associated mesenchymal stem cells (GA-MSCs) play an important role in the formation of the immunosuppressive microenvironment, but the mechanism is still not clear.

RESULTS

We found that GA-MSCs promoted the expression of CD73, an ectonucleotidase that drives immunosuppressive microenvironment maintenance by generating adenosine, on myeloid-derived suppressor cells (MDSCs) through immunosuppressive exosomal miR-21 signaling. This process was similar to the immunosuppressive signaling mediated by glioma exosomal miR-21 but more intense. Further study showed that the miR-21/SP1/DNMT1 positive feedback loop in MSCs triggered by glioma exosomal CD44 upregulated MSC exosomal miR-21 expression, amplifying the glioma exosomal immunosuppressive signal. Modified dendritic cell-derived exosomes (Dex) carrying miR-21 inhibitors could target GA-MSCs and reduce CD73 expression on MDSCs, synergizing with anti-PD-1 monoclonal antibody (mAb).

CONCLUSIONS

Overall, this work reveals the critical role of MSCs in the glioma microenvironment as signal multipliers to enhance immunosuppressive signaling of glioma exosomes, and disrupting the positive feedback loop in MSCs with modified Dex could improve PD-1 blockade therapy.

Antigen Delivery Systems: Past, Present, and Future

The COVID-19 pandemic has increased demand for safe and effective vaccines. Research to develop vaccines against diseases including Middle East respiratory syndrome, Ebolavirus, human immunodeficiency virus, and various cancers would also contribute to global well-being. For successful vaccine development, the advancement of technologies such as antigen (Ag) screening, Ag delivery systems and adjuvants, and manufacturing processes is essential. Ag delivery systems are required not only to deliver a sufficient amount of Ag for vaccination, but also to enhance immune response. In addition, Ag types and their delivery systems determine the manufacturing processes of the vaccine product. Here, we analyze the characteristics of various Ag delivery systems: plasmids, viral vectors, bacterial vectors, nanoparticles, self-assembled particles, natural and artificial cells, and extracellular vesicles. This review provides insight into the current vaccine landscape and highlights promising avenues of research for the development and improvement of Ag delivery systems.

Recent Advances in Nanomaterials-Based Targeted Drug Delivery for Preclinical Cancer Diagnosis and Therapeutics

Nano-oncology is a branch of biomedical research and engineering that focuses on using nanotechnology in cancer diagnosis and treatment. Nanomaterials are extensively employed in the field of oncology because of their minute size and ultra-specificity. A wide range of nanocarriers, such as dendrimers, micelles, PEGylated liposomes, and polymeric nanoparticles are used to facilitate the efficient transport of anti-cancer drugs at the target tumor site. Real-time labeling and monitoring of cancer cells using quantum dots is essential for determining the level of therapy needed for treatment. The drug is targeted to the tumor site either by passive or active means. Passive targeting makes use of the tumor microenvironment and enhanced permeability and retention effect, while active targeting involves the use of ligand-coated nanoparticles. Nanotechnology is being used to diagnose the early stage of cancer by detecting cancer-specific biomarkers using tumor imaging. The implication of nanotechnology in cancer therapy employs photoinduced nanosensitizers, reverse multidrug resistance, and enabling efficient delivery of CRISPR/Cas9 and RNA molecules for therapeutic applications. However, despite recent advancements in nano-oncology, there is a need to delve deeper into the domain of designing and applying nanoparticles for improved cancer diagnostics.

Photosensitive Small Extracellular Vesicles Regulate the Immune Microenvironment of Triple Negative Breast Cancer

Currently, the treatment of triple-negative breast cancer (TNBC) is limited by the special pathological characteristics of this disease. In recent years, photodynamic therapy (PDT) has created new hope for the treatment of TNBC. Moreover, PDT can induce immunogenic cell death (ICD) and improve tumor immunogenicity. However, even though PDT can improve the immunogenicity of TNBC, the inhibitory immune microenvironment of TNBC still weakens the antitumor immune response. Therefore, we used the neutral sphingomyelinase inhibitor GW4869 to inhibit the secretion of small extracellular vesicles (sEVs) by TNBC cells to improve the tumor immune microenvironment and enhance antitumor immunity. In addition, bone mesenchymal stem cell (BMSC)-derived sEVs have good biological safety and a strong drug loading capacity, which can effectively improve the efficiency of drug delivery. In this study, we first obtained primary BMSCs and sEVs, and then the photosensitizers Ce6 and GW4869 were loaded into the sEVs by electroporation to produce immunomodulatory photosensitive nanovesicles (Ce6-GW4869/sEVs). When administered to TNBC cells or orthotopic TNBC models, these photosensitive sEVs could specifically target TNBC and improve the tumor immune microenvironment. Moreover, PDT combined with GW4869-based therapy showed a potent synergistic antitumor effect mediated by direct killing of TNBC and activation of antitumor immunity. Here, we designed photosensitive sEVs that could target TNBC and regulate the tumor immune microenvironment, providing a potential approach for improving the effectiveness of TNBC treatment. STATEMENT OF SIGNIFICANCE: We designed an immunomodulatory photosensitive nanovesicle (Ce6-GW4869/sEVs) with the photosensitizer Ce6 to achieve photodynamic therapy and the neutral sphingomyelinase inhibitor GW4869 to inhibit the secretion of small extracellular vesicles (sEVs) by triple-negative breast cancer (TNBC) cells to improve the tumor immune microenvironment and enhance antitumor immunity. In this study, the immunomodulatory photosensitive nanovesicle could target TNBC cells and regulate the tumor immune microenvironment, thus providing a potential approach for improving the treatment effect in TNBC. We found that the reduction in tumor sEVs secretion induced by GW4869 improved the tumor-suppressive immune microenvironment. Moreover, similar therapeutic strategies can also be applied in other kinds of tumors, especially immunosuppressive tumors, which is of great value for the clinical translation of tumor immunotherapy.

Overcoming Suppressive Tumor Microenvironment by Vaccines in Solid Tumor

Conventional vaccines are widely used to boost human natural ability to defend against foreign invaders, such as bacteria and viruses. Recently, therapeutic cancer vaccines attracted the most attention for anti-cancer therapy. According to the main components, it can be divided into five types: cell, DNA, RNA, peptide, and virus-based vaccines. They mainly perform through two rationales: (1) it trains the host immune system to protect itself and effectively eradicate cancer cells; (2) these vaccines expose the immune system to molecules associated with cancer that enable the immune system to recognize and destroy cancer cells. In this review, we thoroughly summarized the potential strategies and technologies for developing cancer vaccines, which may provide critical achievements for overcoming the suppressive tumor microenvironment through vaccines in solid tumors.

Small Extracellular Vesicles as a New Class of Medicines

Extracellular vesicles (EVs) are nanovesicles that are naturally released from cells in a lipid bilayer-bound form. A subset population with a size of 200 nm, small EVs (sEVs), is enticing in many ways. Initially perceived as mere waste receptacles, sEVs have revealed other biological functions, such as cell-to-cell signal transduction and communication. Besides their notable biological functions, sEVs have profound advantages as future drug modalities: (i) excellent biocompatibility, (ii) high stability, and (iii) the potential to carry undruggable macromolecules as cargo. Indeed, many biopharmaceutical companies are utilizing sEVs, not only as diagnostic biomarkers but as therapeutic drugs. However, as all inchoate fields are challenging, there are limitations and hindrances in the clinical translation of sEV therapeutics. In this review, we summarize different types of sEV therapeutics, future improvements, and current strategies in large-scale production.

Exosomal microRNA Therapy for Non-Small-Cell Lung Cancer

With the progress of molecular diagnosis research on non-small cell lung cancer (NSCLC) cells, four identified categories of microRNAs have been found to be related to disease diagnosis, diagnosis of treatment resistance, prediction of prognosis, and drugs for treatment. To date, nine target mRNA/signal pathways have been confirmed for microRNA drug therapy both in vitro and in vivo. When microRNA drugs enter blood vessels, they target the tumor site and play a similar role to that of targeted drugs. However, whether they will produce serious off-target effects remains unknown, and further clinical research is needed. This review provides the first summary of microRNA therapy for NSCLC.

Regulation of Extracellular Vesicle-Mediated Immune Responses against Antigen-Specific Presentation

Extracellular vesicles (EVs) produced by various immune cells, including B and T cells, macrophages, dendritic cells (DCs), natural killer (NK) cells, and mast cells, mediate intercellular communication and have attracted much attention owing to the novel delivery system of molecules in vivo. DCs are among the most active exosome-secreting cells of the immune system. EVs produced by cancer cells contain cancer antigens; therefore, the development of vaccine therapy that does not require the identification of cancer antigens using cancer-cell-derived EVs may have significant clinical implications. In this review, we summarise the molecular mechanisms underlying EV-based immune responses and their therapeutic effects on tumour vaccination.

Recent Advances in Extracellular Vesicle-Based Therapies Using Induced Pluripotent Stem Cell-Derived Mesenchymal Stromal Cells

Extracellular vesicles (EVs) are being widely investigated as acellular therapeutics in regenerative medicine applications. EVs isolated from mesenchymal stromal cells (MSCs) are by far the most frequently used in preclinical models for diverse therapeutic applications, including inflammatory, degenerative, or acute diseases. Although they represent promising tools as cell-free therapeutic agents, one limitation to their use is related to the batch-to-batch unreliability that may arise from the heterogeneity between MSC donors. Isolating EVs from MSCs derived from induced pluripotent stem cells (iMSCs) might allow unlimited access to cells with a more stable phenotype and function. In the present review, we first present the latest findings regarding the functional aspects of EVs isolated from iMSCs and their interest in regenerative medicine for the treatment of various diseases. We will then discuss future directions for their translation to clinics with good manufacturing practice implementation.