Cancer exosomes and natural killer cells dysfunction: biological roles, clinical significance and implications for immunotherapy

Akkermansia muciniphila activates natural killer cells by suppressing the TGF-β signaling pathway in lung adenocarcinoma cells

Lung adenocarcinoma (LUAD) stands out as a prevalent malignant tumor necessitating innovative strategies to enhance therapeutic outcomes. Akkermansia muciniphila (AKK) has emerged as intricately linked to tumor immunotherapy, yet its impact on natural killer (NK) cells, which play a crucial role in immunotherapy, remains unclear. This study aims to investigate the effects of AKK outer membrane proteins on NK cells in LUAD and elucidate potential associated molecular mechanisms. 16S rRNA sequencing was employed to analyze bacterial genera and their abundance in fecal samples from LUAD patients. Co-culturing of NK-92 cells with LUAD cells, with or without treatment of AKK outer membrane protein Amuc_1100, was conducted to investigate the mechanisms of AKK on LUAD. Additionally, a xenograft mouse model was established to validate the effects of AKK in an in vivo setting. The experimental findings indicated that LUAD patients with elevated AKK levels in their fecal samples demonstrated increased NK cell infiltration and reduced TGF-β levels. Treatment with Amuc_1100 elevated TNF-α and IL-15 cytokine levels, decreased TGF-β levels and proteins associated with TGF-β pathway, enhanced NK cell cytotoxicity, upregulated perforin and granzyme B expression, induced apoptosis and cell cycle arrest, thereby inhibiting cancer cell proliferation. Amuc_1100 also impeded tumor growth in vivo. In summary, these results suggest that AKK activates NK cells to target tumor cells by suppressing the TGF-β signaling pathway in LUAD cells, underscoring the potential of Akk as an effective immunotherapeutic agent in LUAD NK cell-directed therapies.

EGCG targeting STAT3 transcriptionally represses PLXNC1 to inhibit M2 polarization mediated by gastric cancer cell-derived exosomal miR-92b-5p

BACKGROUND

M2-polarized tumor-associated macrophages (TAMs) predominate in tumor microenvironment (TME) and serve primary functions in tumor progression, including growth, angiogenesis, metastasis, immunosuppression, chemoresistance, and poor prognosis. The reversal of M2 polarization provides a new treatment strategy for cancer. Presently, the molecular mechanisms of M2 polarization have yet to be fully characterized, and there is a lack of effective therapeutic targets and drugs. Cancer cells initiate an immunosuppressive TME by recruiting macrophages and promoting M2 polarization through the secretion of inflammatory factors. Accordingly, blocking cancer cell-induced TAM M2 polarization may present a more effective strategy from the perspective of cancer cells. Hedyotis diffusa Willd (HDW) possesses immunomodulatory and antitumor properties, and is a precious and direct source of small molecule natural products with a dual function of inhibition of tumor growth and tumor cell-mediated M2 polarization.

OBJECTIVE

To identify a new target promoting gastric cancer (GC) cell growth and GC cell-mediated M2 polarization from mRNA profiles of GC cells treated with HDW injection (HDI) and to excavate a natural product from HDI that can regulate related mRNA and inhibit the aforementioned effects.

METHODS

RNA sequencing (RNA-seq) was used to analyze HDI-regulated differentially expressed mRNAs (HRmRNAs) in MKN45 cells. Weighted gene co-expression network analysis (WGCNA), univariate and multivariate Cox regression analysis, KM survival curves, and association analysis between HRmRNA and clinical characteristics/tumor infiltrating immune cells (TIICs) individually were utilized to screen out the target HRmRNA associated with prognosis and M2 macrophage infiltration in GC. shRNA lentiviral vectors were used for stably silencing, and transient overexpressing plasmids were constructed for overexpression. CCK8, EdU, colony formation, migration and invasion assays were used to validate the function of drugs and molecules in GC. HDI constituent analysis was performed using UHPLC-QE-MS. A network of HDI constituent-hub transcription factor (TF)-HRmRNA was constructed based on RNA-Seq, network pharmacology and TFs prediction. Exosome isolation and identification were performed using ultracentrifugation, NTA, TEM and western blot. Apoptosis and macrophage phenotypes were determined by flow cytometric analysis. Small RNA-Seq made exosomal miRNA identification. Small molecule interaction with targets were analyzed using molecular docking, SPR and CETSA. The direct relationship between transcription factors and promoters was verified using ChIP-QPCR and dual-luciferase reporter gene assay. A nude mice xenograft tumor model was established for vivo validation.

RESULTS

HDI inhibited MKN45 cell proliferation, migration, invasion and promoted apoptosis. RNA-Seq identified 2583 HRmRNAs. PLXNC1 was screened out as the target HRmRNA associated with prognosis and M2 macrophage infiltration in GC. PLXNC1 promoted GC cell proliferation and facilitated TAMs M2 polarization by transferring GC cell-derived exosomal miR-92b-5p, inhibiting SOCS7-STAT3 interactions and subsequently activating STAT3 in macrophages. M2 TAMs induced by PLXNC1-mediated GC cell-derived exosomes promoted GC cell migration and invasion. PLXNC1 regulated exosomal miR-92b-5p through the MEK1/MSK1/CREB1 pathway. STAT3 could transcriptionally regulate PLXNC1 expression in GC cells. The network of HDI constituent-hub TF-HRmRNA showed epigallocatechin gallate (EGCG) from HDI targeted STAT3 to transcriptionally regulate PLXNC1 expression. EGCG as a natural product directly bound to STAT3 to diminish its nuclear localization, resulting in the transcriptional repression of PLXNC1 and the reversal of M2 polarization induced by PLXNC1-mediated GC cell-derived exosomes.

CONCLUSION

PLXNC1 is a novel target exerting dual effects on GC cell proliferation and GC cell-mediated M2 polarization. EGCG derived from HDI inhibits GC cell proliferation and targets STAT3 to inhibit M2 polarization induced by PLXNC1-mediated exosomes derived from GC cells, which may be a multi-target therapeutic agent for GC cell proliferation and immune microenvironment.

Artificially Modified NK Cell-Based Synergistic Immuno-Gene-Photodynamic Therapy for Cancer

Background

The immunotherapeutic approach utilizing Natural Killer (NK) cells for cancer treatment has garnered significant interest owing to its inherent cytotoxicity, immunomodulatory properties, demonstrated safety in in vivo studies. However, multiple immunosuppressive mechanisms in the tumor microenvironment (TME) suppress the anticancer effect of NK cells in the treatment of solid tumors. Herein, a smart NK cell drug delivery system (DDS) with photo-responsive and TME-responsive properties was designed.

Methods

The NK cell DDS consists of two parts: the carrier is living NK cell with pH-low (abbreviated as NKpH) insertion peptide on its surface, the cargo is reductive-responsive nanogel (NG) encapsulated siRNA and photosensitizer (abbreviated as SP-NG), the final carrier was abbreviated as SP-NG@ NKpH. Firstly, pHLip helped artificially modified NK cell target and anchor onto cancer and exert the efficacy of cellular immunotherapy. Then, the strategy of combining photoactivation and bioreduction responsiveness achieved the precise release of cargos in cancer cells. Finally, the DDS combined the effect of the immunotherapy of NK cell, the gene therapy of siRNA, and the photodynamic therapy of photosensitizer.

Results

Under near-infrared laser irradiation, SP-NG@NKpH induced an increase in reactive oxygen species (ROS) within cells, exacerbated cell membrane permeability, and allowed for rapid drug release. Within the tumor microenvironment (TME), NG exhibits highly sensitive reducibility for drug release. The SP-NG released from NK cells can be uptaken by tumor cells. When exposed to near-infrared laser irradiation, SP-NG@NKpH demonstrates significant tumor-targeting specificity and cytotoxicity.

Discussion

The combined effect of the immunotherapy of NK cell, the gene therapy of siRNA, and the photodynamic therapy of photosensitizer obtained a stronger cancer killing effect in vitro and in vivo. Therefore, this versatile NK cell DDS exhibits a good clinical application prospect.

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

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

Role of tumor-derived exosomes mediated immune cell reprograming in cancer

Tumor-derived exosomes (TDEs), as topologies of tumor cells, not only carry biological information from the mother, but also act as messengers for cellular communication. It has been demonstrated that TDEs play a key role in inducing an immunosuppressive tumor microenvironment (TME). They can reprogram immune cells indirectly or directly by delivering inhibitory proteins, cytokines, RNA and other substances. They not only inhibit the maturation and function of dendritic cells (DCs) and natural killer (NK) cells, but also remodel M2 macrophages and inhibit T cell infiltration to promote immunosuppression and create a favorable ecological niche for tumor growth, invasion and metastasis. Based on the specificity of TDEs, targeting TDEs has become a new strategy to monitor tumor progression and enhance treatment efficacy. This paper reviews the intricate molecular mechanisms underlying the immunosuppressive effects induced by TDEs to establish a theoretical foundation for cancer therapy. Additionally, the challenges of TDEs as a novel approach to tumor treatment are discussed.

Extracellular vesicle-mediated crosstalk in tumor microenvironment dominates tumor fate

The tumor microenvironment (TME) is a complex and heterogeneous system containing various cells cooperating and competing with each other. Extracellular vesicles (EVs) differing in form and content are important intercellular communication mediators in the TME. Previous studies have focused on the cargoes within EVs rather than on the donors from which they originate and the recipient cells that exert their effects. Therefore, we provide here a detailed overview of the important roles of EVs in shaping tumor fate, highlighting their various mechanisms of intercellular dialog within the TME. We evaluate recent advances and also raise unresolved challenges to provide new ideas for clinical treatment strategies using EVs.

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

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

Exosomes: from basic research to clinical diagnostic and therapeutic applications in cancer

Cancer continues to pose a global threat despite potent anticancer drugs, often accompanied by undesired side effects. To enhance patient outcomes, sophisticated multifunctional approaches are imperative. Small extracellular vesicles (EVs), a diverse family of naturally occurring vesicles derived from cells, offer advantages over synthetic carriers. Among the EVs, the exosomes are facilitating intercellular communication with minimal toxicity, high biocompatibility, and low immunogenicity. Their tissue-specific targeting ability, mediated by surface molecules, enables precise transport of biomolecules to cancer cells. Here, we explore the potential of exosomes as innovative therapeutic agents, including cancer vaccines, and their clinical relevance as biomarkers for clinical diagnosis. We highlight the cargo possibilities, including nucleic acids and drugs, which make them a good delivery system for targeted cancer treatment and contrast agents for disease monitoring. Other general aspects, sources, and the methodology associated with therapeutic cancer applications are also reviewed. Additionally, the challenges associated with translating exosome-based therapies into clinical practice are discussed, together with the future prospects for this innovative approach.

Immune-Cell-Derived Exosomes as a Potential Novel Tool to Investigate Immune Responsiveness in SCLC Patients: A Proof-of-Concept Study

Small cell lung cancer (SCLC) is a highly invasive and rapidly proliferating lung tumor subtype. Most patients respond well to a combination of platinum-based chemotherapy and PD-1/PDL-1 inhibitors. Unfortunately, not all patients benefit from this treatment regimen, and few alternative therapies are available. In this scenario, the identification of new biomarkers and differential therapeutic strategies to improve tumor response becomes urgent. Here, we investigated the role of exosomes (EXs) released from the peripheral blood mononuclear cells (PBMCs) of SCLC patients in mediating the functional crosstalk between the immune system and tumors in response to treatments. In this study, we showed that PBMC-EXs from SCLC patients with different responses to chemoimmunotherapy showed different levels of immune (STING and MAVS) and EMT (Snail and c-Myc) markers. We demonstrated that PBMC-EXs derived from best responder (BR) patients were able to induce a significant increase in apoptosis in SCLC cell lines in vitro compared to PBMC-EXs derived from non-responder (NR) SCLC patients. PBMC-EXs were able to affect cell viability and modulate apoptotic markers, DNA damage and the replication stress pathway, as well as the occurrence of EMT. Our work provides proof of concept that PBMC-EXs can be used as a tool to study the crosstalk between cancer cells and immune cells and that PBMC-EXs exhibit an in vitro ability to promote cancer cell death and reduce tumor aggressiveness.

Regulation of the PD-1/PD-L1 Axis and NK Cell Dysfunction by Exosomal miR-552-5p in Gastric Cancer

OBJECTIVE

NK cells play a vital role in tumor immune resistance. Various factors affect NK cell activity. While NK cell dysfunction has been observed in numerous malignancies, the underlying mechanisms in gastric cancer remain unclear.

METHOD

Flow cytometry was used to identify the phenotypic distribution and expression of activated receptors on NK cells. ELISA was used to determine the expression of cytokines. We examined the expression of NK cell-related genes and explored their association with survival and prognosis. Additionally, we conducted PCR detection of miR-552-5p expression levels in plasma exosomes of patients and investigated its correlation with phenotypic distribution and activated receptors. We used flow cytometry and ELISA to verify the role of miR-552-5p in NK cell dysfunction. Furthermore, we investigated the potential role of PD-1/PD-L1 in regulating NK cell dysfunction in patients' cells.

RESULTS

We observed a significant decrease in the percentage of NKG2D and NKp30 and IFN-γ and TNF-α in patients than in healthy volunteers. Patients with low levels of CD56, CD16, NKG2D, and NKP46 exhibited poorer survival prognoses. Moreover, increased expression levels of plasma exosomal miR-552-5p in patients were negatively associated with NK cell phenotypic distribution and activated receptor expression. MiR-552-5p downregulated the secretion of perforin, granzyme, and IFN-γ as well as the expression of NKp30, NKp46, and NKG2D. Additionally, it suppressed the cytotoxicity of NK cells. The inhibitory effect of miR-552-5p, on NK cell function was reversed when anti-PD-L1 antibodies were used.

CONCLUSION

Exosomal miR-552-5p targets the PD-1/PD-L1 axis, leading to impaired NK cell function.

Insights of immune cell heterogeneity, tumor-initiated subtype transformation, drug resistance, treatment and detecting technologies in glioma microenvironment

BACKGROUND

With the gradual understanding of glioma development and the immune microenvironment, many immune cells have been discovered. Despite the growing comprehension of immune cell functions and the clinical application of immunotherapy, the precise roles and characteristics of immune cell subtypes, how glioma induces subtype transformation of immune cells and its impact on glioma progression have yet to be understood.

AIM OF THE REVIEW

In this review, we comprehensively center on the four major immune cells within the glioma microenvironment, particularly neutrophils, macrophages, lymphocytes, myeloid-derived suppressor cells (MDSCs), and other significant immune cells. We discuss (1) immune cell subtype markers, (2) glioma-induced immune cell subtype transformation, (3) the mechanisms of each subtype influencing chemotherapy resistance, (4) therapies targeting immune cells, and (5) immune cell-associated single-cell sequencing. Eventually, we identified the characteristics of immune cell subtypes in glioma, comprehensively summarized the exact mechanism of glioma-induced immune cell subtype transformation, and concluded the progress of single-cell sequencing in exploring immune cell subtypes in glioma.

KEY SCIENTIFIC CONCEPTS OF REVIEW

In conclusion, we have analyzed the mechanism of chemotherapy resistance detailly, and have discovered prospective immunotherapy targets, excavating the potential of novel immunotherapies approach that synergistically combines radiotherapy, chemotherapy, and surgery, thereby paving the way for improved immunotherapeutic strategies against glioma and enhanced patient outcomes.

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

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

The role of extracellular vesicles in cancer

Extracellular vesicles (EVs), which include small EVs such as exosomes, play a critical role in intercellular communication and are produced by both cancer and non-cancer cells. Several studies have shown that cancer cells exploit various strategies to regulate the biogenesis, composition, and functions of EVs primarily to promote cancer progression. Given that exosomes originate from major sorting hubs at the limiting membrane of endosomes, they are central to a signaling network that connects external stimuli with intrinsic tumor cell features. Exosomes contain diverse repertoires of molecular cargos, such as proteins, lipids, and nucleic acids, which determine their heterogeneity and functional properties in cancer progression. Therefore, targeting exosome biogenesis will enhance our understanding of tumorigenesis and also promote the discovery of novel approaches for cancer therapy. In this chapter we summarize the machinery of exosome biogenesis and the local, distant, and systemic effects of exosomes released by cancer cells. Furthermore, we explore how these exosomes regulate the anti-tumor immune response and epigenetic mechanisms to sustain cancer progression and their implications in cancer prevention and treatment.

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

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

Current approaches in glioblastoma multiforme immunotherapy

Glioblastoma multiform (GBM) is the most prevalent CNS (central nervous system) tumor in adults, with an average survival length shorter than 2 years and rare metastasis to organs other than CNS. Despite extensive attempts at surgical resecting, the inherently permeable nature of this disease has rendered relapse nearly unavoidable. Thus, immunotherapy is a feasible alternative, as stimulated immune cells can enter into the remote and inaccessible tumor cells. Immunotherapy has revolutionized patient upshots in various malignancies and might introduce different effective ways for GBM patients. Currently, researchers are exploring various immunotherapeutic strategies in patients with GBM to target both the innate and acquired immune responses. These approaches include reprogrammed tumor-associated macrophages, the use of specific antibodies to inhibit tumor progression and metastasis, modifying tumor-associated macrophages with antibodies, vaccines that utilize tumor-specific dendritic cells to activate anti-tumor T cells, immune checkpoint inhibitors, and enhanced T cells that function against tumor cells. Despite these findings, there is still room for improving the response faults of the many currently tested immunotherapies. This study aims to review the currently used immunotherapy approaches with their molecular mechanisms and clinical application in GBM.

Application of biomimetic nanovaccines in cancer immunotherapy: A useful strategy to help combat immunotherapy resistance

Breakthroughs in actual clinical applications have begun through vaccine-based cancer immunotherapy, which uses the body's immune system, both humoral and cellular, to attack malignant cells and fight diseases. However, conventional vaccine approaches still face multiple challenges eliciting effective antigen-specific immune responses, resulting in immunotherapy resistance. In recent years, biomimetic nanovaccines have emerged as a promising alternative to conventional vaccine approaches by incorporating the natural structure of various biological entities, such as cells, viruses, and bacteria. Biomimetic nanovaccines offer the benefit of targeted antigen-presenting cell (APC) delivery, improved antigen/adjuvant loading, and biocompatibility, thereby improving the sensitivity of immunotherapy. This review presents a comprehensive overview of several kinds of biomimetic nanovaccines in anticancer immune response, including cell membrane-coated nanovaccines, self-assembling protein-based nanovaccines, extracellular vesicle-based nanovaccines, natural ligand-modified nanovaccines, artificial antigen-presenting cells-based nanovaccines and liposome-based nanovaccines. We also discuss the perspectives and challenges associated with the clinical translation of emerging biomimetic nanovaccine platforms for sensitizing cancer cells to immunotherapy.

Exosomal noncoding RNAs: decoding their role in thyroid cancer progression

Exosomes, as pivotal entities within the tumor microenvironment, orchestrate intercellular communication through the transfer of diverse molecules, among which non-coding RNAs (ncRNAs) such as miRNAs, lncRNAs, and circRNAs play a crucial role. These ncRNAs, endowed with regulatory functions, are selectively incorporated into exosomes. Emerging evidence underscores the significance of exosomal ncRNAs in modulating key oncogenic processes in thyroid cancer (TC), including proliferation, metastasis, epithelial-mesenchymal transition (EMT), angiogenesis, and immunoediting. The unique composition of exosomes shields their cargo from enzymatic and chemical degradation, ensuring their integrity and facilitating their specific expression in plasma. This positions exosomal ncRNAs as promising candidates for novel diagnostic and prognostic biomarkers in TC. Moreover, the potential of exosomes in the therapeutic landscape of TC is increasingly recognized. This review aims to elucidate the intricate relationship between exosomal ncRNAs and TC, fostering a deeper comprehension of their mechanistic involvement. By doing so, it endeavors to propel forward the exploration of exosomal ncRNAs in TC, ultimately paving the way for innovative diagnostic and therapeutic strategies predicated on exosomes and their ncRNA content.

Environmental pollutants and exosomes: A new paradigm in environmental health and disease

This study investigates the intricate interplay between environmental pollutants and exosomes, shedding light on a novel paradigm in environmental health and disease. Cellular stress, induced by environmental toxicants or disease, significantly impacts the production and composition of exosomes, crucial mediators of intercellular communication. The heat shock response (HSR) and unfolded protein response (UPR) pathways, activated during cellular stress, profoundly influence exosome generation, cargo sorting, and function, shaping intercellular communication and stress responses. Environmental pollutants, particularly lipophilic ones, directly interact with exosome lipid bilayers, potentially affecting membrane stability, release, and cellular uptake. The study reveals that exposure to environmental contaminants induces significant changes in exosomal proteins, miRNAs, and lipids, impacting cellular function and health. Understanding the impact of environmental pollutants on exosomal cargo holds promise for biomarkers of exposure, enabling non-invasive sample collection and real-time insights into ongoing cellular responses. This research explores the potential of exosomal biomarkers for early detection of health effects, assessing treatment efficacy, and population-wide screening. Overcoming challenges requires advanced isolation techniques, standardized protocols, and machine learning for data analysis. Integration with omics technologies enhances comprehensive molecular analysis, offering a holistic understanding of the complex regulatory network influenced by environmental pollutants. The study underscores the capability of exosomes in circulation as promising biomarkers for assessing environmental exposure and systemic health effects, contributing to advancements in environmental health research and disease prevention.

Exosomal noncoding RNAs in gynecological cancers: implications for therapy resistance and biomarkers

Gynecologic cancers, including ovarian cancer (OC), cervical cancer (CC), and endometrial cancer (EC), pose a serious threat to women's health and quality of life due to their high incidence and lethality. Therapeutic resistance in tumors refers to reduced sensitivity of tumor cells to therapeutic drugs or radiation, which compromises the efficacy of treatment or renders it ineffective. Therapeutic resistance significantly contributes to treatment failure in gynecologic tumors, although the specific molecular mechanisms remain unclear. Exosomes are nanoscale vesicles released and received by distinct kinds of cells. Exosomes contain proteins, lipids, and RNAs closely linked to their origins and functions. Recent studies have demonstrated that exosomal ncRNAs may be involved in intercellular communication and can modulate the progression of tumorigenesis, aggravation and metastasis, tumor microenvironment (TME), and drug resistance. Besides, exosomal ncRNAs also have the potential to become significant diagnostic and prognostic biomarkers in various of diseases. In this paper, we reviewed the biological roles and mechanisms of exosomal ncRNAs in the drug resistance of gynecologic tumors, as well as explored the potential of exosomal ncRNAs acting as the liquid biopsy molecular markers in gynecologic cancers.

Intercellular crosstalk between cancer cells and cancer-associated fibroblasts via exosomes in gastrointestinal tumors

Gastrointestinal (GI) tumors are a significant global health threat, with high rates of morbidity and mortality. Exosomes contain various biologically active molecules like nucleic acids, proteins, and lipids and can serve as messengers for intercellular communication. They play critical roles in the exchange of information between tumor cells and the tumor microenvironment (TME). The TME consists of mesenchymal cells and components of the extracellular matrix (ECM), with fibroblasts being the most abundant cell type in the tumor mesenchyme. Cancer-associated fibroblasts (CAFs) are derived from normal fibroblasts and mesenchymal stem cells that are activated in the TME. CAFs can secrete exosomes to modulate cell proliferation, invasion, migration, drug resistance, and other biological processes in tumors. Additionally, tumor cells can manipulate the function and behavior of fibroblasts through direct cell-cell interactions. This review provides a summary of the intercellular crosstalk between GI tumor cells and CAFs through exosomes, along with potential underlying mechanisms.

CAR-NK cells for cancer immunotherapy: recent advances and future directions

Natural Killer (NK) cells, intrinsic to the innate immune system, are pivotal in combating cancer due to their independent cytotoxic capabilities in antitumor immune response. Unlike predominant treatments that target T cell immunity, the limited success of T cell immunotherapy emphasizes the urgency for innovative approaches, with a spotlight on harnessing the potential of NK cells. Despite tumors adapting mechanisms to evade NK cell-induced cytotoxicity, there is optimism surrounding Chimeric Antigen Receptor (CAR) NK cells. This comprehensive review delves into the foundational features and recent breakthroughs in comprehending the dynamics of NK cells within the tumor microenvironment. It critically evaluates the potential applications and challenges associated with emerging CAR-NK cell therapeutic strategies, positioning them as promising tools in the evolving landscape of precision medicine. As research progresses, the unique attributes of CAR-NK cells offer a new avenue for therapeutic interventions, paving the way for a more effective and precise approach to cancer treatment.

Tumor-derived lncRNAs: Behind-the-scenes mediators that modulate the immune system and play a role in cancer pathogenesis

Having been involved in complex cellular regulatory networks and cell-to-cell communications, non-coding RNAs (lncRNAs) have become functional carriers that transmit information between cells and tissues, modulate tumor microenvironments, encourage angiogenesis and invasion, and make tumor cells more resistant to drugs. Immune cells' exosomal lncRNAs may be introduced into tumor cells to influence the tumor's course and the treatment's effectiveness. Research has focused on determining if non-coding RNAs affect many target genes to mediate regulating recipient cells. The tumor microenvironment's immune and cancer cells are influenced by lncRNAs, which may impact a treatment's efficacy. The lncRNA-mediated interaction between cancer cells and immune cells invading the tumor microenvironment has been the subject of numerous recent studies. On the other hand, tumor-derived lncRNAs' control over the immune system has not gotten much attention and is still a relatively new area of study. Tumor-derived lncRNAs are recognized to contribute to tumor immunity, while the exact mechanism is unclear.

Breakthrough of solid tumor treatment: CAR-NK immunotherapy

As the latest and most anticipated method of tumor immunotherapy, CAR-NK therapy has received increasing attention in recent years, and its safety and high efficiency have irreplaceable advantages over CAR-T. Current research focuses on the application of CAR-NK in hematological tumors, while there are fewer studies on solid tumor. This article reviews the process of constructing CAR-NK, the effects of hypoxia and metabolic factors, NK cell surface receptors, cytokines, and exosomes on the efficacy of CAR-NK in solid tumor, and the role of CAR-NK in various solid tumor. The mechanism of action and the research status of the potential of CAR-NK in the treatment of solid tumor in clinical practice, and put forward the advantages, limitations and future problems of CAR-NK in the treatment of solid tumor.

The role and application of vesicles in triple-negative breast cancer: Opportunities and challenges

Extracellular vesicles (EVs) carry DNA, RNA, protein, and other substances involved in intercellular crosstalk and can be used for the targeted delivery of drugs. Triple-negative breast cancer (TNBC) is rich in recurrent and metastatic disease and lacks therapeutic targets. Studies have proved the role of EVs in the different stages of the genesis and development of TNBC. Cancer cells actively secrete various biomolecules, which play a significant part establishing the tumor microenvironment via EVs. In this article, we describe the roles of EVs in the tumor immune microenvironment, metabolic microenvironment, and vascular remodeling, and summarize the application of EVs for objective delivery of chemotherapeutic drugs, immune antigens, and cancer vaccine adjuvants. EVs-based therapy may represent the next-generation tool for targeted drug delivery for the cure of a variety of diseases lacking effective drug treatment.

Exploiting innate immunity for cancer immunotherapy

Immunotherapies have revolutionized the treatment paradigms of various types of cancers. However, most of these immunomodulatory strategies focus on harnessing adaptive immunity, mainly by inhibiting immunosuppressive signaling with immune checkpoint blockade, or enhancing immunostimulatory signaling with bispecific T cell engager and chimeric antigen receptor (CAR)-T cell. Although these agents have already achieved great success, only a tiny percentage of patients could benefit from immunotherapies. Actually, immunotherapy efficacy is determined by multiple components in the tumor microenvironment beyond adaptive immunity. Cells from the innate arm of the immune system, such as macrophages, dendritic cells, myeloid-derived suppressor cells, neutrophils, natural killer cells, and unconventional T cells, also participate in cancer immune evasion and surveillance. Considering that the innate arm is the cornerstone of the antitumor immune response, utilizing innate immunity provides potential therapeutic options for cancer control. Up to now, strategies exploiting innate immunity, such as agonists of stimulator of interferon genes, CAR-macrophage or -natural killer cell therapies, metabolic regulators, and novel immune checkpoint blockade, have exhibited potent antitumor activities in preclinical and clinical studies. Here, we summarize the latest insights into the potential roles of innate cells in antitumor immunity and discuss the advances in innate arm-targeted therapeutic strategies.

Small extracellular vesicle TGF-β in cancer progression and immune evasion

Transforming growth factor-β (TGF-β) is a well-known cytokine that controls various processes in normal physiology and disease context. Strong preclinical and clinical literature supports the crucial roles of the TGF-β in several aspects of cancer biology. Recently emerging evidence reveals that the release of TGF-β from tumor/immune/stromal cells in small extracellular vesicles (sEVs) plays an important part in tumor development and immune evasion. Hence, this review aims to address the packaging, release, and signaling pathways of TGF-β carried in sEVs (sEV-TGF-β) in cancer, and to explore its underpinning roles in tumor development, growth, progression, metastasis, etc. We also highlight key progresses in deciphering the roles of sEV-TGF-β in subverting anti-tumor immune responses. The paper ends with a focus on the clinical significance of TGF-β carried in sEVs and draws attention to its diagnostic, therapeutic, and prognostic importance.

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.

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.

Tumor-derived nanoseeds condition the soil for metastatic organotropism

Primary tumors secrete a variety of factors to turn distant microenvironments into favorable and fertile 'soil' for subsequent metastases. Among these 'seeding' factors that initiate pre-metastatic niche (PMN) formation, tumor-derived extracellular vesicles (EVs) are of particular interest as tumor EVs can direct organotropism depending on their surface integrin profiles. In addition, EVs also contain versatile, bioactive cargo, which include proteins, metabolites, lipids, RNA, and DNA fragments. The cargo incorporated into EVs is collectively shed from cancer cells and cancer-associated stromal cells. Increased understanding of how tumor EVs promote PMN establishment and detection of EVs in bodily fluids highlight how tumor EVs could serve as potential diagnostic and prognostic biomarkers, as well as provide a therapeutic target for metastasis prevention. This review focuses on tumor-derived EVs and how they direct organotropism and subsequently modulate stromal and immune microenvironments at distal sites to facilitate PMN formation. We also outline the progress made thus far towards clinical applications of tumor EVs.

New Possible Ways to Use Exosomes in Diagnostics and Therapy via JAK/STAT Pathways

Exosomes have the potential to be the future of personalized diagnostics and therapy. They are nano-sized particles between 30 and 100 nm flowing in the extracellular milieu, where they mediate cell-cell communication and participate in immune system regulation. Tumor-derived exosomes (TDEs) secreted from different types of cancer cells are the key regulators of the tumor microenvironment. With their immune suppressive cargo, TDEs prevent the antitumor immune response, leading to reduced effectiveness of cancer treatment by promoting a pro-tumorigenic microenvironment. Involved signaling pathways take part in the regulation of tumor proliferation, differentiation, apoptosis, and angiogenesis. Signal transducers and activators of transcription factors (STATs) and Janus kinase (JAK) signaling pathways are crucial in malignancies and autoimmune diseases alike, and their potential to be manipulated is currently the focus of interest. In this review, we aim to discuss exosomes, TDEs, and the JAK/STAT pathways, along with mediators like interleukins, tripartite motif proteins, and interferons.

How Nanotherapeutic Platforms Play a Key Role in Glioma? A Comprehensive Review of Literature

Glioblastoma (GBM), a highly aggressive form of brain cancer, is considered one of the deadliest cancers, and even with the most advanced medical treatments, most affected patients have a poor prognosis. However, recent advances in nanotechnology offer promising avenues for the development of versatile therapeutic and diagnostic nanoplatforms that can deliver drugs to brain tumor sites through the blood-brain barrier (BBB). Despite these breakthroughs, the use of nanoplatforms in GBM therapy has been a subject of great controversy due to concerns over the biosafety of these nanoplatforms. In recent years, biomimetic nanoplatforms have gained unprecedented attention in the biomedical field. With advantages such as extended circulation times, and improved immune evasion and active targeting compared to conventional nanosystems, bionanoparticles have shown great potential for use in biomedical applications. In this prospective article, we endeavor to comprehensively review the application of bionanomaterials in the treatment of glioma, focusing on the rational design of multifunctional nanoplatforms to facilitate BBB infiltration, promote efficient accumulation in the tumor, enable precise tumor imaging, and achieve remarkable tumor suppression. Furthermore, we discuss the challenges and future trends in this field. Through careful design and optimization of nanoplatforms, researchers are paving the way toward safer and more effective therapies for GBM patients. The development of biomimetic nanoplatform applications for glioma therapy is a promising avenue for precision medicine, which could ultimately improve patient outcomes and quality of life.

The tumor immune microenvironment in pancreatic cancer and its potential in the identification of immunotherapy biomarkers

INTRODUCTION

Pancreatic cancer (PC) has an extremely poor prognosis, even with surgical resection and triplet chemotherapy treatment. Cancer immunotherapy has been recently approved for tumor-agnostic treatment with genome analysis, including in PC. However, it has limited efficacy.

AREAS COVERED

In addition to the low tumor mutation burden, one of the difficulties of immunotherapy in PC is the presence of abundant stromal cells in its microenvironment. Among stromal cells, cancer-associated fibroblasts (CAFs) play a major role in immunotherapy resistance, and CAF-targeted therapies are currently under development, including those in combination with immunotherapies. Meanwhile, microbiomes and tumor-derived exosomes (TDEs) have been shown to alter the behavior of distant receptor cells in PC. This review discusses the role of CAFs, microbiomes, and TDEs in PC tumor immunity.

EXPERT OPINION

Elucidating the mechanisms by which CAFs, microbiomes, and TDEs are involved in the tumorigenesis of PC will be helpful for developing novel immunotherapeutic strategies and identifying companion biomarkers for immunotherapy. Spatial single-cell analysis of the tumor microenvironment will be useful for identifying biomarkers of PC immunity. Furthermore, given the complexity of immune mechanisms, artificial intelligence models will be beneficial for predicting the efficacy of immunotherapy.

CCR7 Mediated Mimetic Dendritic Cell Vaccine Homing in Lymph Node for Head and Neck Squamous Cell Carcinoma Therapy

Immunotherapy has been recognized as one of the most promising treatment strategies for head and neck squamous cell carcinoma (HNSCC). As a pioneering trend of immunotherapy, dendritic cell (DC) vaccines have displayed the ability to prime an immune response, while the insufficient immunogenicity and low lymph node (LN) targeting efficiency, resulted in an unsubstantiated therapeutic efficacy in clinical trials. Herein, a hybrid nanovaccine (Hy-M-Exo) is developed via fusing tumor-derived exosome (TEX) and dendritic cell membrane vesicle (DCMV). The hybrid nanovaccine inherited the key protein for lymphatic homing, CCR7, from DCMV and demonstrated an enhanced efficiency of LN targeting. Meanwhile, the reserved tumor antigens and endogenous danger signals in the hybrid nanovaccine activated antigen presenting cells (APCs) elicited a robust T-cell response. Moreover, the nanovaccine Hy-M-Exo displayed good therapeutic efficacy in a mouse model of HNSCC. These results indicated that Hy-M-Exo is of high clinical value to serve as a feasible strategy for antitumor immunotherapy.

Exosomal circular RNAs: A chief culprit in cancer chemotherapy resistance

Chemotherapy is one of the primary treatments for malignant tumors. However, the acquired drug resistance hinders clinical efficacy and leads to treatment failure in most patients. Exosomes are cell-derived vesicles with a diameter of 30-150 nm carrying and delivering substances such as DNAs, RNAs, lipids, and proteins for cellular communication in tumor development. Circular RNAs (circRNAs) present covalently closed-loop RNA structures, which regulate tumor cell proliferation, apoptosis, and metastasis by controlling different genes and signaling pathways. CircRNAs are abundant and stably expressed in exosomes. Recent studies have shown that they play critical roles in chemotherapy resistance in various cancers. In this review, we summarized the origin of exosomes and discussed the regulation mechanism of exosomal circRNAs in cancer drug resistance.

NK cells are never alone: crosstalk and communication in tumour microenvironments

Immune escape is a hallmark of cancer. The dynamic and heterogeneous tumour microenvironment (TME) causes insufficient infiltration and poor efficacy of natural killer (NK) cell-based immunotherapy, which becomes a key factor triggering tumour progression. Understanding the crosstalk between NK cells and the TME provides new insights for optimising NK cell-based immunotherapy. Here, we present new advances in direct or indirect crosstalk between NK cells and 9 specialised TMEs, including immune, metabolic, innervated niche, mechanical, and microbial microenvironments, summarise TME-mediated mechanisms of NK cell function inhibition, and highlight potential targeted therapies for NK-TME crosstalk. Importantly, we discuss novel strategies to overcome the inhibitory TME and provide an attractive outlook for the future.

Exosomes-mediated tumor metastasis through reshaping tumor microenvironment and distant niche

Tumor-derived exosomes (TDEs) are the particular communicator and messenger between tumor cells and other cells containing cancer-associated genetic materials and proteins. And TDEs who are also one of the important components consisting of the tumor microenvironment (TME) can reshape and interact with TME to promote tumor development and metastasis. Moreover, due to their long-distance transmission by body fluids, TDEs can facilitate the formation of pre-metastatic niche to support tumor colonization. We discuss the main characteristics and mechanism of TDE-mediated tumor metastasis by reshaping TME and pre-metastatic niche as well as the potential of TDEs for diagnosing tumor and predicting future metastatic development.

Blockade of exosome release alters HER2 trafficking to the plasma membrane and gives a boost to Trastuzumab

OBJECTIVE(S)

Exosomal HER2 has been evidenced to interfere with antibody-induced anti-tumor effects. However, whether the blockade of HER2+ exosomes release would affect antibody-mediated tumor inhibition has yet to be investigated.

METHODS

Exosomes derived from BT-474, SK-BR3 and SK-OV3 (HER2-overexpressing tumor cells) and MDA-MB-231 cells (HER2 negative) were purified and characterized by bicinchoninic acid (BCA) assay, western blotting and Transmission electron microscopy (TEM). Inhibition of exosome release was achieved by neutral sphingomyelinase-2 (nSMase-2) inhibitor, GW4869. The effects of exosome blockade on the anti-proliferative effects, apoptosis induction, and antibody-mediated cellular cytotoxicity (ADCC) activity of Trastuzumab were examined using MTT, flow cytometry, and LDH release assays. Also, the effects of exosome inhibition on the surface expression and endocytosis/internalization of HER2 were studied by flow cytometry.

RESULTS

Purified exosomes derived from HER2 overexpressing cancer cells were positive for HER2 protein. Blockade of exosome release was able to significantly improve apoptosis induction, anti-proliferative and ADCC responses of Trastuzumab dose dependently. The pretreatment of Trastuzumab/purified NK cells, but not PBMCs, with HER2+ exosomes could also decrease the ADCC effects of Trastuzumab. Exosome inhibition also remarkably downregulated surface HER2 levels in a time-dependent manner, but does not affect its endocytosis/internalization.

CONCLUSION

Based on our findings, HER2+ exosomes may benefit tumor progression by dually suppressing Trastuzumab-induced tumor growth inhibition and cytotoxicity of NK cells. It seems that concomitant blocking of exosome release might be an effective approach for improving the therapeutic effects of Trastuzumab, and potentially other HER2-directed mAbs. In addition, the exosome secretion pathway possibly contributes to the HER2 trafficking to plasma membrane, since the blockade of exosome secretion decreased surface HER2 levels.

The Biological Effect of Small Extracellular Vesicles on Colorectal Cancer Metastasis

Colorectal cancer (CRC) is a malignancy that seriously threatens human health, and metastasis from CRC is a major cause of death and poor prognosis for patients. Studying the potential mechanisms of small extracellular vesicles (sEVs) in tumor development may provide new options for early and effective diagnosis and treatment of CRC metastasis. In this review, we systematically describe how sEVs mediate epithelial mesenchymal transition (EMT), reconfigure the tumor microenvironment (TME), modulate the immune system, and alter vascular permeability and angiogenesis to promote CRC metastasis. We also discuss the current difficulties in studying sEVs and propose new ideas.

Diverse Neutrophil Functions in Cancer and Promising Neutrophil-Based Cancer Therapies

Neutrophils represent the most abundant cell type of leukocytes in the human blood and have been considered a vital player in the innate immune system and the first line of defense against invading pathogens. Recently, several studies showed that neutrophils play an active role in the immune response during cancer development. They exhibited both pro-oncogenic and anti-tumor activities under the influence of various mediators in the tumor microenvironment. Neutrophils can be divided into several subpopulations, thus contradicting the traditional concept of neutrophils as a homogeneous population with a specific function in the innate immunity and opening new horizons for cancer therapy. Despite the promising achievements in this field, a full understanding of tumor-neutrophil interplay is currently lacking. In this review, we try to summarize the current view on neutrophil heterogeneity in cancer, discuss the different communication pathways between tumors and neutrophils, and focus on the implementation of these new findings to develop promising neutrophil-based cancer therapies.

Extracellular vesicles biogenesis, isolation, manipulation and genetic engineering for potential in vitro and in vivo therapeutics: An overview

The main goals of medicine consist of early detection and effective treatment of different diseases. In this regard, the rise of exosomes as carriers of natural biomarkers has recently attracted a lot of attention and managed to shed more light on the future of early disease diagnosis methods. Here, exosome biogenesis, its role as a biomarker in metabolic disorders, and recent advances in state-of-art technologies for exosome detection and isolation will be reviewed along with future research directions and challenges regarding the manipulation and genetic engineering of exosomes for potential in vitro and in vivo disease diagnosis approaches.

Plasma Exosomal miRNAs Associated With Metabolism as Early Predictor of Gestational Diabetes Mellitus

To date, the miRNA expression profile of plasma exosomes in women whose pregnancy is complicated by gestational diabetes mellitus (GDM) has not been fully clarified. In this study, differentially expressed miRNAs in plasma exosomes were identified by high-throughput small-RNA sequencing in 12 pregnant women with GDM and 12 with normal glucose tolerance (NGT) and validated in 102 pregnant women with GDM and 101 with NGT. A total of 22 exosomal miRNAs were found, five of which were verified by real-time qPCR. Exosomal miR-423-5p was upregulated, whereas miR-122-5p, miR-148a-3p, miR-192-5p, and miR-99a-5p were downregulated in women whose pregnancy was complicated by GDM. IGF1R and GYS1 as target genes of miR-423-5p, and G6PC3 and FDFT1 as target genes of miR-122-5p were associated with insulin and AMPK signaling pathways and may participate in the regulation of metabolism in GDM. The five exosomal miRNAs had an area under the curve of 0.82 (95%CI, 0.73, ∼0.91) in early prediction of GDM. Our study demonstrates that dysregulated exosomal miRNAs in plasma from pregnant women with GDM might influence the insulin and AMPK signaling pathways and could contribute to the early prediction of GDM.

Molecular Docking and Intracellular Translocation of Extracellular Vesicles for Efficient Drug Delivery

Extracellular vesicles (EVs), including exosomes, mediate intercellular communication by delivering their contents, such as nucleic acids, proteins, and lipids, to distant target cells. EVs play a role in the progression of several diseases. In particular, programmed death-ligand 1 (PD-L1) levels in exosomes are associated with cancer progression. Furthermore, exosomes are being used for new drug-delivery systems by modifying their membrane peptides to promote their intracellular transduction via micropinocytosis. In this review, we aim to show that an efficient drug-delivery system and a useful therapeutic strategy can be established by controlling the molecular docking and intracellular translocation of exosomes. We summarise the mechanisms of molecular docking of exosomes, the biological effects of exosomes transmitted into target cells, and the current state of exosomes as drug delivery systems.

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.

The role of extracellular vesicles in osteoarthritis treatment via microenvironment regulation

Osteoarthritis (OA) is a degenerative joint disease that is common among the middle-aged and older populations, causes patients to experience recurrent pain in their joints and negatively affects their quality of life. Currently, therapeutic options for patients with OA consist of medications to alleviate pain and treat the symptoms; however, due to typically poor outcomes, patients with advanced OA are unlikely to avoid joint replacement. In recent years, several studies have linked disrupted homeostasis of the joint cavity microenvironment to the development of OA. Recently, extracellular vesicles (EVs) have received increasing attention in the field of OA. EVs are natural nano-microcarrier materials with unique biological activity that are produced by cells through paracrine action. They are composed of lipid bilayers that contain physiologically active molecules, such as nucleic acids and proteins. Moreover, EVs may participate in local and distal intercellular and intracellular communication. EVs have also recently been shown to influence OA development by regulating biochemical factors in the OA microenvironmental. In this article, we first describe the microenvironment of OA. Then, we provide an overview of EVs, summarize the main types used for the treatment of OA, and describe their mechanisms. Next, we review clinical studies using EVs for OA treatment. Finally, the specific mechanism underlying the application of miRNA-enriched EVs in OA therapy is described.

Strategies for Potentiating NK-Mediated Neuroblastoma Surveillance in Autologous or HLA-Haploidentical Hematopoietic Stem Cell Transplants

Simple Summary

High-risk neuroblastomas (HR-NB) are malignant tumors of childhood that are treated with a very aggressive and life-threatening approach; this includes autologous hemopoietic stem cell transplantation (HSCT) and the infusion of a mAb targeting the GD2 tumor-associated antigen. Although the current treatment provided benefits, the 5-year overall survival remains below 50% due to relapses and refractoriness to therapy. Thus, there is an urgent need to ameliorate the standard therapeutic protocol, particularly improving the immune-mediated anti-tumor responses. Our review aims at summarizing and critically discussing novel immunotherapeutic strategies in HR-NB, including NK cell-based therapies and HLA-haploidentical HSCT from patients’ family.

Abstract

High-risk neuroblastomas (HR-NB) still have an unacceptable 5-year overall survival despite the aggressive therapy. This includes standardized immunotherapy combining autologous hemopoietic stem cell transplantation (HSCT) and the anti-GD2 mAb. The treatment did not significantly change for more than one decade, apart from the abandonment of IL-2, which demonstrated unacceptable toxicity. Of note, immunotherapy is a promising therapeutic option in cancer and could be optimized by several strategies. These include the HLA-haploidentical αβT/B-depleted HSCT, and the antibody targeting of novel NB-associated antigens such as B7-H3, and PD1. Other approaches could limit the immunoregulatory role of tumor-derived exosomes and potentiate the low antibody-dependent cell cytotoxicity of CD16 dim/neg NK cells, abundant in the early phase post-transplant. The latter effect could be obtained using multi-specific tools engaging activating NK receptors and tumor antigens, and possibly holding immunostimulatory cytokines in their construct. Finally, treatments also consider the infusion of novel engineered cytokines with scarce side effects, and cell effectors engineered with chimeric antigen receptors (CARs). Our review aims to discuss several promising strategies that could be successfully exploited to potentiate the NK-mediated surveillance of neuroblastoma, particularly in the HSCT setting. Many of these approaches are safe, feasible, and effective at pre-clinical and clinical levels.

Tumor-derived exosomes deliver the tumor suppressor miR-3591-3p to induce M2 macrophage polarization and promote glioma progression

Exosomes can selectively secrete harmful metabolic substances from cells to maintain cellular homeostasis, and complex crosstalk occurs between exosomes and tumor-associated macrophages (TAMs) in the glioma immune microenvironment. However, the precise mechanisms by which these exosome-encapsulated cargos create an immunosuppressive microenvironment remain unclear. Herein, we investigated the effect of glioma-derived exosomes (GDEs) on macrophage polarization and glioma progression. We performed sequencing analysis of cerebrospinal fluid (CSF) and tumor tissues from glioma patients to identify functional microRNAs (miRNAs). High levels of miR-3591-3p were found in CSF and GDEs but not in normal brain tissue or glial cells. Functionally, GDEs and miR-3591-3p significantly induced M2 macrophage polarization and increased the secretion of IL10 and TGFβ1, which in turn promoted glioma invasion and migration. Moreover, miR-3591-3p overexpression in glioma cell lines resulted in G2/M arrest and markedly increased apoptosis. Mechanistically, miR-3591-3p can directly target CBLB and MAPK1 in macrophages and glioma cells, respectively, and further activate the JAK2/PI3K/AKT/mTOR, JAK2/STAT3, and MAPK signaling pathways. In vivo experiments confirmed that macrophages lentivirally transduced with miR-3591-3p can significantly promote glioma progression. Thus, our study demonstrates that tumor-suppressive miR-3591-3p in glioma cells can be secreted via exosomes and target TAMs to induce the formation of an immunosuppressive microenvironment. Collectively, these findings provide new insights into the role of glioma exosomal miRNAs in mediating the establishment of an immunosuppressive tumor microenvironment and show that miR-3591-3p may be a valuable biomarker and that blocking the encapsulation of miR-3591-3p into exosomes may become a novel immunotherapeutic strategy for glioma.

Exosome-Mediated Immunosuppression in Tumor Microenvironments

Exosomes are membranous structures secreted by nearly all cell types. As critical messengers for intercellular communication, exosomes deliver bioactive cargoes to recipient cells and are involved in multiple physiopathological processes, including immunoregulation. Our pioneering study revealed that cancer cells release programmed death-ligand 1-positive exosomes into the circulation to counter antitumor immunity systemically via T cells. Tumor cell-derived exosomes (TDEs) also play an immunosuppressive role in other immunocytes, including dendritic cells (DCs), macrophages, natural killer (NK) cells, and myeloid-derived suppressor cells (MDSCs). Moreover, exosomes secreted by nontumor cells in the tumor microenvironments (TMEs) also exert immunosuppressive effects. This review systematically provides a summary of the immunosuppression induced by exosomes in tumor microenvironments, which modulates tumor growth, invasion, metastasis, and immunotherapeutic resistance. Additionally, therapeutic strategies targeting the molecular mechanism of exosome-mediated tumor development, which may help overcome several obstacles, such as immune tolerance in oncotherapy, are also discussed. Detailed knowledge of the specific functions of exosomes in antitumor immunity may contribute to the development of innovative treatments.

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.