ICAM-1-mediated adhesion is a prerequisite for exosome-induced T cell suppression

Role of cancer cell-derived exosomal glycoproteins in macrophage polarization

Cancer is a deadly disease marked by abnormal cell growth, proliferation, and metastasis-the spread of cancer from its origin to distant sites. A key factor in tumor progression is the tumor microenvironment (TME), which significantly influences tumor behavior and response to treatment. Within the TME, interactions between cancer cells and surrounding immune cells, particularly tumor-associated macrophages (TAMs), play a critical role in shaping immune responses. This review focuses on recent findings from a systematic PubMed search regarding cancer cell-derived exosomal glycoproteins and their role in modulating macrophage phenotypes. Tumor-derived exosomes, a type of extracellular vesicle (EV), carry glycoproteins-proteins with attached sugar chains-that can influence macrophage polarization. These glycoproteins can reprogram macrophages into either the M1 phenotype (proinflammatory and anti-tumor) or the M2 phenotype (anti-inflammatory and tumor-supportive). The M1 macrophages inhibit tumor progression, while M2 macrophages support tumor growth by promoting immune suppression and tissue remodeling. Understanding how exosomal glycoproteins drive this polarization offers critical insight into cancer immunology and may pave the way for novel therapeutic strategies targeting the TME.

SLC35A2-mediated bisected GlcNAc-modified extracellular vesicles enhance immune regulation in breast cancer lung metastasis

This study investigates the role of SLC35A2-mediated bisected GlcNAc-modified small extracellular vesicles (sEVs) in breast cancer (BC) lung metastasis. By modulating B3GALT1 expression, these sEVs regulate the pre-metastatic immune microenvironment, enhancing CD8+ T cell infiltration and reducing immune evasion. The use of β-peptide-loaded sEVs further amplifies anti-metastatic effects, as demonstrated in vivo mouse models and molecular analyses. These findings underscore the therapeutic potential of glycosylation-modified sEVs in enhancing immune responses and controlling BC metastasis.

Exosome-mediated communication between T cells and dendritic cells: Implications for therapeutic strategies

Cell communication is crucial for coordinating physiological functions in multicellular organisms, with exosomes playing a significant role. Exosomes mediate intercellular communication by transporting proteins, lipids, and nucleic acids between cells. These small, membrane-bound vesicles, derived from the endosomal pathway, are integral to various biological processes, including signal transmission and cellular behavior modulation. Recent advances highlight the potential of exosomes, especially dendritic cell-derived exosomes (DEXs), for diagnostic and therapeutic applications, particularly in cancer immunotherapy. DEXs are distinguished by their ability to present antigens and stimulate immune responses more effectively than exosomes from other cell types. They carry a cargo rich in immunostimulatory molecules and MHC-peptide complexes, which facilitate robust T-cell activation and enhance tumor-specific immune responses. The unique properties of DEXs, such as their ability to cross biological barriers and resist tumor-induced immunosuppression, position them as promising candidates for therapeutic applications. Here, I review the reports on the bidirectional interaction between dendritic cells and T cells through exosomes and their role in medicine.

Overcoming extracellular vesicle-mediated fratricide improves CAR T cell treatment against solid tumors

The efficacy of chimeric antigen receptor (CAR) T cells against solid tumors is limited. The molecular mechanisms underlying CAR T cell resistance are yet to be elucidated and new strategies need to be developed to improve treatment outcomes. Here we report that solid tumors respond to CAR T cells by upregulating the secretion of small extracellular vesicles carrying tumor antigens, which are horizontally transferred to CAR T cells, leading to antigen recognition and CAR T cell fratricide. Engineered CAR T cells armored with Serpin B9, a major granzyme B inhibitor, show decreased fratricide and increased vitality, tumor infiltration, and antitumor activity in female mice. Moreover, Serpin B9-armored CAR T cells show higher efficacy than parental CAR T cells in treating solid tumors when combined with the anti-programmed death 1 antibody. Our study demonstrates a mechanism that limits CAR T cell function and suggests an improved strategy in tumor treatment.

Dual role of interferon-gamma in the response of melanoma patients to immunotherapy with immune checkpoint inhibitors

Interferon-gamma (IFN-γ) is a cytokine produced mainly by immune cells and can affect cancer cells by modulating the activity of multiple signaling pathways, including the canonical Janus-activated kinase/signal transducer and activator of transcription (JAK/STAT) cascade. In melanoma, IFN-γ can exert both anticancer effects associated with cell-cycle arrest and cell death induction and protumorigenic activity related to immune evasion leading to melanoma progression. Notably, IFN-γ plays a crucial role in the response of melanoma patients to immunotherapy with immune checkpoint inhibitors (ICIs), which are currently used in the clinic. As these agents target programmed death-1 (PD-1) and its ligand (PD-L1), cytotoxic T-lymphocyte-associated protein-4 (CTLA-4) and lymphocyte-activation gene 3 (LAG-3), they are designed to restore the antimelanoma immune response. In this respect, IFN-γ produced by cells in the tumor microenvironment in response to ICIs has a beneficial influence on both immune and melanoma cells by increasing antigen presentation, recruiting additional T-cells to the tumor site, and inducing direct antiproliferative effects and apoptosis in melanoma cells. Therefore, IFN-γ itself and IFN-γ-related gene signatures during the response to ICIs can constitute biomarkers or predictors of the clinical outcome of melanoma patients treated with ICIs. However, owing to its multifaceted roles, IFN-γ can also contribute to developing mechanisms associated with the acquisition of resistance to ICIs. These mechanisms can be associated with either decreased IFN-γ levels in the tumor microenvironment or diminished responsiveness to IFN-γ due to changes in the melanoma phenotypes associated with affected activity of other signaling pathways or genetic alterations e.g., in JAK, which restricts the ability of melanoma cells to respond to IFN-γ. In this respect, the influence of IFN-γ on melanoma-specific regulators of the dynamic plasticity of the cell phenotype, including microphthalmia-associated transcription factor (MITF) and nerve growth factor receptor (NGFR)/CD271 can affect the clinical efficacy of ICIs. This review comprehensively discusses the role of IFN-γ in the response of melanoma patients to ICIs with respect to its positive influence and role in IFN-γ-related mechanisms of resistance to ICIs as well as the potential use of predictive markers on the basis of IFN-γ levels and signatures of IFN-γ-dependent genes.

Effect of Extracellular Vesicles Derived From Tumor Cells on Immune Evasion

The crosstalk between immunity and cancer in the regulation of tumor growth is considered a hallmark of cancer. Antitumor immunity refers to the innate and adaptive immune responses that regulate cancer development and proliferation. Tumor immune evasion represents a major hindrance to effective anticancer treatment. Extracellular vesicles (EVs) are nano-sized and lipid-bilayer-enclosed particles that are secreted to the extracellular space by all cell types. They are critically involved in numerous biological functions including intercellular communication. Tumor-derived extracellular vesicles (TEVs) can transport a variety of cargo to modulate immune cells in the tumor microenvironment (TME). This review provides the latest update about how tumor cells evade immune surveillance by exploiting TEVs. First, the biogenesis of EVs and the cargo-sorting machinery are discussed. Second, how tumor cells modulate immune cell differentiation, activation, and function via TEVs to evade immune surveillance is illustrated. Last but not least, the novel antitumor strategies that can reverse immune escape are summarized.

Hypoxia regulates small extracellular vesicle biogenesis and cargo sorting through HIF-1α/HRS signaling pathway in head and neck squamous cell carcinoma

Small extracellular vesicles (sEVs) act as crucial messengers that transmit biological signals in hypoxic tumor microenvironment (TME), significantly impacting cancer progression. However, the precise mechanism by which hypoxia influences sEV biogenesis remains poorly understood. In this study, we observed increased sEV secretion and alterations in cargo composition in head and neck squamous cell carcinoma (HNSCC) cells under hypoxic conditions. We found that hepatocyte growth factor-regulated tyrosine kinase substrate (HRS), a key component of the endosomal sorting complexes required for transport (ESCRT), was upregulated during hypoxia. This upregulation activated the endosomal system and reduced degradation of multivesicular bodies (MVBs). HRS depletion altered the packaging of protein cargoes such as mitochondria-related proteins into sEVs under hypoxia, and these cargoes promoted a pro-tumorigenic phenotype of macrophages. Importantly, we demonstrated that HRS is transcriptionally activated by hypoxia inducible factor-1α (HIF-1α). Spatial transcriptomics and immunohistochemistry revealed a positive correlation between HRS and HIF-1α. These findings establish a link between the hypoxic response, sEV biogenesis, and cargo packaging, enhancing our understanding of how the hypoxic TME influences sEV biogenesis in HNSCC cells.

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.

Exosome-mediated Crosstalk in the Tumor Immune Microenvironment: Critical Drivers of Hepatocellular Carcinoma Progression

Hepatocellular carcinoma (HCC) is a significant global health issue, ranking as the sixth most prevalent malignancy and the fourth leading cause of cancer-related mortality worldwide. Despite advancements in therapeutic strategies, mortality rates for HCC remain high. The tumor immune microenvironment (TIME) plays a vital role in HCC progression by influencing tumor cell survival and growth. Recent studies highlight the essential role of exosomes in mediating intercellular communication within the TIME, particularly in interactions among tumor cells, immune cells, and fibroblasts. These interactions drive critical aspects of tumor development, including immune escape, angiogenesis, drug resistance, and metastasis. A detailed understanding of the molecular mechanisms by which exosomes modulate the TIME is essential for developing targeted therapies. This review systematically evaluated the roles and regulatory mechanisms of exosomes within the TIME of HCC, examining the impact of both HCC-derived and non-HCC-derived exosomes on various cellular components within the TIME. It emphasized their regulatory effects on cell phenotypes and functions, as well as their roles in HCC progression. The review also explored the potential applications of exosome-based immunotherapies, offering new insights into improving therapeutic strategies for HCC.

Utilizing Nanoparticles to Overcome Anti-PD-1/PD-L1 Immunotherapy Resistance in Non-Small Cell Lung cancer: A Potential Strategy

Lung cancer is the leading cause of cancer-related mortality globally, with non-small cell lung cancer (NSCLC) constituting 85% of cases. Immune checkpoint inhibitors (ICIs) represented by anti-programmed cell death protein 1 (PD-1)/ programmed cell death ligand 1 (PD-L1) have emerged as a promising frontier in cancer treatment, effectively extending the survival of patients with NSCLC. However, the efficacy of ICIs exhibits significant variability across diverse patient populations, with a substantial proportion showing poor responsiveness and acquired resistance in those initially responsive to ICIs treatments. With the advancement of nanotechnology, nanoparticles offer unique advantages in tumor immunotherapy, including high permeability and prolonged retention(EPR) effects, enhanced drug delivery and stability, and modulation of the inflammatory tumor microenvironment(TME). This review summarizes the mechanisms of resistance to ICIs in NSCLC, focusing on tumor antigens loss and defective antigen processing and presentation, failure T cell priming, impaired T cell migration and infiltration, immunosuppressive TME, and genetic mutations. Furthermore, we discuss how nanoparticles, through their intrinsic properties such as the EPR effect, active targeting effect, shielding effect, self-regulatory effect, and synergistic effect, can potentiate the efficacy of ICIs and reverse resistance. In conclusion, nanoparticles serve as a robust platform for ICIs-based NSCLC therapy, aiding in overcoming resistance challenges.

Extracellular vesicles in tumor immunity: mechanisms and novel insights

Extracellular vesicles (EVs), nanoscale vesicles secreted by cells, have attracted considerable attention in recent years due to their role in tumor immunomodulation. These vesicles facilitate intercellular communication by transporting proteins, nucleic acids, and other biologically active substances, and they exhibit a dual role in tumor development and immune evasion mechanisms. Specifically, EVs can assist tumor cells in evading immune surveillance and attack by impairing immune cell function or modulating immunosuppressive pathways, thereby promoting tumor progression and metastasis. Conversely, they can also transport and release immunomodulatory factors that stimulate the activation and regulation of the immune system, enhancing the body's capacity to combat malignant diseases. This dual functionality of EVs presents promising avenues and targets for tumor immunotherapy. By examining the biological characteristics of EVs and their influence on tumor immunity, novel therapeutic strategies can be developed to improve the efficacy and relevance of cancer treatment. This review delineates the complex role of EVs in tumor immunomodulation and explores their potential implications for cancer therapeutic approaches, aiming to establish a theoretical foundation and provide practical insights for the advancement of future EVs-based cancer immunotherapy strategies.

Exosomes: Key Messengers Mediating the Interaction Between Tumor Cells and CD8+ T Cells in the Tumor Microenvironment

In recent years, with an increasingly profound comprehension of the tumor microenvironment, it has been discovered that the constituent cells within the immune microenvironment, such as macrophages, CD4+T cells, and CD8+T cells, interact with tumor cells in manners conducive to tumorigenesis and progression. Exosomes play a pivotal role as essential mediators for intercellular material exchange and signal transmission in this context. Tumor cell-derived exosomes carrying cargo such as PD-L1 and ncRNAs engage with CD8+T cells to induce cytotoxic responses and facilitate immune evasion, thereby promoting tumor advancement. When combined with current immune checkpoint inhibitors like anti-PD-L1/PD-1 therapy, enhancing CD8+T cell function through exosomal pathways while monitoring and augmenting therapeutic effects can significantly improve efficacy. This review delineates the crucial role of exosomes derived from both tumor cells and CD8+T cells within the tumor microenvironment along with their impact mechanisms on both tumor cells and CD8+T cells. Furthermore, it summarizes the potential for clinical treatment in this realm when integrated with existing immunotherapy methods-particularly exploring the feasibility of clinical translation alongside engineering materials science techniques.

The effect of cancer cell-derived exosomal proteins on macrophage polarization: An in-depth review

Cancer is characterized by unregulated cell proliferation, enabling it to invade and spread to different organs and tissues in the body. Cancer progression is intricately influenced by the complex dynamics within the tumor microenvironment (TME). The TME is a composite and dynamic network comprising cancer cells and various immune cells, including tumor-associated macrophages. Exosomes facilitate the communication between different cancer cells as well as other types of cells. This review particularly focuses on exosomal proteins derived from different cancer cells in mounting the complex crosstalk between cells of cancer and macrophages within the TME. Most cancer-derived exosomal proteins polarize macrophages towards M2 phenotype, promoting cancer aggressiveness, while a few have role switching towards the M1 phenotype, inhibiting cancer proliferation, respectively. In this review, we summarize, for the first time, the dual impact of cancer cell-derived exosomal proteins on macrophage polarization and the associated signaling pathways, offering valuable insights for developing innovative therapeutic strategies against diverse cancer types.

CD8+ T cell exhaustion in the tumor microenvironment of breast cancer

CD8+ T cells are crucial cytotoxic components of the tumor immune system. In chronic inflammation, they become low-responsive, a state known as T cell exhaustion (TEX). The aim of immune checkpoint blockade is to counteract TEX, yet its dynamics in breast cancer remain poorly understood. This review defines CD8+ TEX and outlines its features and underlying mechanisms. It also discusses the primary mechanisms of CD8+ TEX in breast cancer, covering inhibitory receptors, immunosuppressive cells, cytokines, transcriptomic and epigenetic alterations, metabolic reprogramming, and exosome pathways, offering insights into potential immunotherapy strategies for breast cancer.

Exosomes in stroke management: a promising paradigm shift in stroke therapy

Effective treatment methods for stroke, a common cerebrovascular disease with a high mortality rate, are still being sought. Exosome therapy, a form of acellular therapy, has demonstrated promising efficacy in various diseases in animal models; however, there is currently insufficient evidence to guide the clinical application of exosome in patients with stroke. This article reviews the progress of exosome applications in stroke treatment. It aims to elucidate the significant potential value of exosomes in stroke therapy and provide a reference for their clinical translation. At present, many studies on exosome-based therapies for stroke are actively underway. Regarding preclinical research, exosomes, as bioactive substances with diverse sources, currently favor stem cells as their origin. Due to their high plasticity, exosomes can be effectively modified through various physical, chemical, and genetic engineering methods to enhance their efficacy. In animal models of stroke, exosome therapy can reduce neuroinflammatory responses, alleviate oxidative stress damage, and inhibit programmed cell death. Additionally, exosomes can promote angiogenesis, repair and regenerate damaged white matter fiber bundles, and facilitate the migration and differentiation of neural stem cells, aiding the repair process. We also summarize new directions for the application of exosomes, specifically the exosome intervention through the ventricular-meningeal lymphatic system. The review findings suggest that the treatment paradigm for stroke is poised for transformation.

Tumour-derived small extracellular vesicles act as a barrier to therapeutic nanoparticle delivery

Nanoparticles are promising for drug delivery applications, with several clinically approved products. However, attaining high nanoparticle accumulation in solid tumours remains challenging. Here we show that tumour cell-derived small extracellular vesicles (sEVs) block nanoparticle delivery to tumours, unveiling another barrier to nanoparticle-based tumour therapy. Tumour cells secrete large amounts of sEVs in the tumour microenvironment, which then bind to nanoparticles entering tumour tissue and traffic them to liver Kupffer cells for degradation. Knockdown of Rab27a, a gene that controls sEV secretion, decreases sEV levels and improves nanoparticle accumulation in tumour tissue. The therapeutic efficacy of messenger RNAs encoding tumour suppressing and proinflammatory proteins is greatly improved when co-encapsulated with Rab27a small interfering RNA in lipid nanoparticles. Together, our results demonstrate that tumour cell-derived sEVs act as a defence system against nanoparticle tumour delivery and that this system may be a potential target for improving nanoparticle-based tumour therapies.

Extracellular vesicles in cancers: mechanisms, biomarkers, and therapeutic strategies

Extracellular vesicles (EVs) composed of various biologically active constituents, such as proteins, nucleic acids, lipids, and metabolites, have emerged as a noteworthy mode of intercellular communication. There are several categories of EVs, including exosomes, microvesicles, and apoptotic bodies, which largely differ in their mechanisms of formation and secretion. The amount of evidence indicated that changes in the EV quantity and composition play a role in multiple aspects of cancer development, such as the transfer of oncogenic signals, angiogenesis, metabolism remodeling, and immunosuppressive effects. As EV isolation technology and characteristics recognition improve, EVs are becoming more commonly used in the early diagnosis and evaluation of treatment effectiveness for cancers. Actually, EVs have sparked clinical interest in their potential use as delivery vehicles or vaccines for innovative antitumor techniques. This review will focus on the function of biological molecules contained in EVs linked to cancer progression and their participation in the intricate interrelationship within the tumor microenvironment. Furthermore, the potential efficacy of an EV-based liquid biopsy and delivery cargo for treatment will be explored. Finally, we explicitly delineate the limitations of EV-based anticancer therapies and provide an overview of the clinical trials aimed at improving EV development.

The roles of PD-L1 in the various stages of tumor metastasis

The interaction between tumor programmed death ligand 1 (PD-L1) and T-cell programmed cell death 1 (PD-1) has long been acknowledged as a mechanism for evading immune surveillance. Recent studies, however, have unveiled a more nuanced role of tumor-intrinsic PD-L1 in reprograming tumoral phenotypes. Preclinical models emphasize the synchronized effects of both intracellular and extracellular PD-L1 in promoting metastasis, with intricate interactions with the immune system. This review aims to summarize recent findings to elucidate the spatiotemporal heterogeneity of PD-L1 expression and the pro-metastatic roles of PD-L1 in the entire process of tumor metastasis. For example, PD-L1 regulates the epithelial-to-mesenchymal transition (EMT) process, facilitates the survival of circulating tumor cells, and induces the formation of immunosuppressive environments at pre-metastatic niches and metastatic sites. And the complexed and dynamic regulation process of PD-L1 for tumor metastasis is related to the spatiotemporal heterogeneity of PD-L1 expression and functions from tumor primary sites to various metastatic sites. This review extends the current understandings for the roles of PD-L1 in mediating tumor metastasis and provides new insights into therapeutic decisions in clinical practice.

The Nature and Nurture of Extracellular Vesicle-Mediated Signaling

In the last decade, it has become clear that extracellular vesicles (EVs) are a ubiquitous component of living systems. These small membrane-enclosed particles can confer diverse functions to the cells that release, capture, or coexist with them in an environment. We use examples across living systems to produce a conceptual framework that classifies three modes by which EVs exert functions: (a) EV release that serves a function for producing cells, (b) EV modification of the extracellular environment, and (c) EV interactions with, and alteration of, receiving cells. We provide an overview of the inherent properties of EVs (i.e., their nature) as well as factors in the environment and receiving cell (i.e., nurture) that determine whether transmission of EV cargo leads to functional cellular responses. This review broadens the context for ruminating on EV functions and highlights the emergent properties of EVs that define their role in biology and will shape their applications in medicine.

Influencing immunity: role of extracellular vesicles in tumor immune checkpoint dynamics

Immune checkpoint proteins (ICPs) serve as critical regulators of the immune system, ensuring protection against damage due to overly activated immune responses. However, within the tumor environment, excessive ICP activation weakens antitumor immunity. Despite the development of numerous immune checkpoint blockade (ICB) drugs in recent years, their broad application has been inhibited by uncertainties about their clinical efficacy. A thorough understanding of ICP regulation in the tumor microenvironment is essential for advancing the development of more effective and safer ICB therapies. Extracellular vesicles (EVs), which are pivotal mediators of cell-cell communication, have been extensively studied and found to play key roles in the functionality of ICPs. Nonetheless, a comprehensive review summarizing the current knowledge about the crosstalk between EVs and ICPs in the tumor environment is lacking. In this review, we summarize the interactions between EVs and several widely studied ICPs as well as their potential clinical implications, providing a theoretical basis for further investigation of EV-related ICB therapeutic approaches.

Extracellular vesicles reshape the tumor microenvironment to improve cancer immunotherapy: Current knowledge and future prospects

Tumor immunotherapy has revolutionized cancer treatment, but limitations remain, including low response rates and immune complications. Extracellular vesicles (EVs) are emerging as a new class of therapeutic agents for various diseases. Recent research shows that changes in the amount and composition of EVs can reshape the tumor microenvironment (TME), potentially improving the effectiveness of immunotherapy. This exciting discovery has sparked clinical interest in using EVs to enhance the immune system's response to cancer. In this Review, we delve into the world of EVs, exploring their origins, how they're generated, and their complex interactions within the TME. We also discuss the crucial role EVs play in reshaping the TME during tumor development. Specifically, we examine how their cargo, including molecules like PD-1 and non-coding RNA, influences the behavior of key immune cells within the TME. Additionally, we explore the current applications of EVs in various cancer therapies, the latest advancements in engineering EVs for improved immunotherapy, and the challenges faced in translating this research into clinical practice. By gaining a deeper understanding of how EVs impact the TME, we can potentially uncover new therapeutic vulnerabilities and significantly enhance the effectiveness of existing cancer immunotherapies.

Cancer Stem Cell markers: Symphonic masters of chemoresistance and immune evasion

Cancer Stem Cells (CSCs) are highly tumorigenic, chemoresistant, and immune evasive. They emerge as a central driver that gives rise to the bulk of tumoral mass, modifies the tumor microenvironment (TME), and exploits it, leading to poor clinical outcomes for patients with cancer. The existence of CSCs thus accounts for the failure of conventional therapies and immune surveillance. Identifying CSCs in solid tumors remains a significant challenge in modern oncology, with the use of cell surface markers being the primary strategy for studying, isolating, and enriching these cells. In this review, we explore CSC markers, focusing on the underlying signaling pathways that drive CSC self-renewal, which simultaneously makes them intrinsically chemoresistant and immune system evaders. We comprehensively discuss the autonomous and non-autonomous functions of CSCs, with particular emphasis on their interactions with the tumor microenvironment, especially immune cells. This reciprocal network enhances CSCs malignancy while compromising the surrounding niche, ultimately defining therapeutic vulnerabilities associated with each CSC marker. The most common CSCs surface markers addressed in this review-CD44, CD133, ICAM1/CD54, and LGR5-provide insights into the interplay between chemoresistance and immune evasion, two critically important phenomena in disease eradication. This new perspective on the state-of-the-art of CSCs will undoubtedly open new avenues for therapy.

Targeting overexpressed surface proteins: A new strategy to manage the recalcitrant triple-negative breast cancer

Triple-negative breast cancer (TNBC) is an aggressive and heterogeneous cancer that lacks all three molecular markers, Estrogen, Progesterone, and Human Epidermal Growth Factor Receptor 2 (HER2). This unique characteristic of TNBC makes it more resistant to hormonal therapy; hence, chemotherapy and surgery are preferred. Active targeting with nanoparticles is more effective in managing TNBC than a passive approach. The surface of TNBC cells overexpresses several cell-specific proteins, which can be explored for diagnostic and therapeutic purposes. Immunohistochemical analysis has revealed that TNBC cells overexpress αVβ3 integrin, Intercellular Adhesion Molecule 1 (ICAM-1), Glucose Transporter 5 (GLUT5), Transmembrane Glycoprotein Mucin 1 (MUC-1), and Epidermal Growth Factor Receptor (EGFR). These surface proteins can be targeted using ligands, such as aptamers, antibodies, and sugar molecules. Targeting the surface proteins of TNBC with ligands helps harmonize treatment and improve patient compliance. In this review, we discuss the proteins expressed, which are limited to αVβ3 integrin proteins, ICAM-1, GLUT-5, MUC1, and EGFR, on the surface of TNBC, the challenges associated with the preclinical setup of breast cancer for targeted nanoformulations, internalization techniques and their challenges, suggestions to overcome the limitations of successful translation of nanoparticles, and the possibility of ligand-conjugated nanoparticles targeting these surface receptors for a better therapeutic outcome.

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

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

Combination of radiotherapy and immunotherapy in duality with the protumoral action of radiation

Radiotherapy is widely used to treat various cancers. Its combination with immune checkpoint inhibitors is intensively studied preclinically and clinically. Although the first results were very encouraging, the number of patients who respond positively remains low, and the therapeutic benefit is often temporary. This review summarizes how radiation can stimulate an antitumor immune response and its combination with immunotherapy based on inhibiting immune checkpoints. We will provide an overview of radiotherapy parameters that should be better controlled to avoid downregulating the antitumor immune response. The low response rate of combining radiotherapy and immunotherapy could, at least in part, be caused by the stimulation of cancer cell invasion and metastasis development that occur at similar doses and number of radiation fractions. To end on a positive note, we explore how a targeted inhibition of the inflammatory cytokines induced by radiation with a cyclooxygenase-2 inhibitor could both support an antitumor immune response and block radiation-induced metastasis formation.

Integrin α6-containing extracellular vesicles promote lymphatic remodelling for pre-metastatic niche formation in lymph nodes via interplay with CD151

Heterogeneous extracellular vesicles (EVs) from various types of tumours are acknowledged for inducing the formation of pre-metastatic "niches" in draining lymph nodes (LNs) to promote lymphatic metastasis. In order to identify the specific subpopulations of EVs involved, we performed high-resolution proteomic analysis combined with nanoflow cytometry of bladder cancer (BCa) tissue-derived EVs to identify a novel subset of tumour-derived EVs that contain integrin α6 (ITGA6+EVs) and revealed the positive correlation of ITGA6+EVs with the formation of pre-metastatic niche in draining LNs and lymphatic metastasis in multicentre clinical analysis of 820-case BCa patients. BCa-derived ITGA6+EVs induced E-selectin (SELE)-marked lymphatic remodelling pre-metastatic niche and promoted metastasis in draining LNs through delivering cargo circRNA-LIPAR to lymphatic endothelial cells in vivo and in vitro. Mechanistically, LIPAR linked ITGA6 to the switch II domain of RAB5A and sustained RAB5A GTP-bound activated state, thus maintaining the production of ITGA6+EVs loaded with LIPAR through endosomal trafficking. ITGA6+EVs targeted lymphatic vessels through ITGA6-CD151 interplay and released LIPAR to induce SELE overexpression-marked lymphatic remodelling pre-metastatic niche. Importantly, we constructed engineered-ITGA6 EVs to inhibit lymphatic pre-metastatic niche, which suppressed lymphatic metastasis and prolonged survival in preclinical models. Collectively, our study uncovers the mechanism of BCa-derived ITGA6+EVs mediating pre-metastatic niche and provides an engineered-EV-based strategy against BCa lymphatic metastasis.

Tumor-derived exosomal ICAM1 promotes bone metastasis of triple-negative breast cancer by inducing CD8+ T cell exhaustion

Exosomes, which are nanosized extracellular vesicles, have emerged as crucial mediators of the crosstalk between tumor cells and the immune system. Intercellular adhesion molecule 1 (ICAM1) plays a crucial role in multiple immune functions as well as in the occurrence, development and metastasis of cancer. As a glycoprotein expressed on the cell membrane, ICAM1 is secreted extracellularly on exosomes and regulates the immunosuppressive microenvironment. However, the role of exosomal ICAM1 in the immune microenvironment of breast cancer bone metastases remains unclear. This study aimed to elucidated the role of exosomal ICAM1 in facilitating CD8+ T cell exhaustion and subsequent bone metastasis in triple-negative breast cancer (TNBC). We demonstrated that TNBC cells release ICAM1-enriched exosomes, and the binding of ICAM1 to its receptor is necessary for the suppressive effect of CD8 T cell proliferation and function. This pivotal engagement not only inhibits CD8+ T cell proliferation and activation but also initiates the development of an immunosuppressive microenvironment that is conducive to TNBC tumor growth and bone metastasis. Moreover, ICAM1 blockade significantly impairs the ability of tumor exosomes to bind to CD8+ T cells, thereby inhibiting their immunosuppressive effects. The present study elucidates the complex interaction between primary tumors and the immune system that is mediated by exosomes and provides a foundation for the development of novel cancer immunotherapies that target ICAM1 with the aim of mitigating TNBC bone metastasis.

Exosome-related gene identification and diagnostic model construction in hepatic ischemia-reperfusion injury

Hepatic ischemia-reperfusion injury (HIRI) may cause severe hepatic impairment, acute hepatic insufficiency, and multiorgan system collapse. Exosomes can alleviate HIRI. Therefore, this study explored the role of exosomal-related genes (ERGs) in HIRI using bioinformatics to determine the underlying molecular mechanisms and novel diagnostic markers for HIRI. We merged the GSE12720, GSE14951, and GSE15480 datasets obtained from the Gene Expression Omnibus (GEO) database into a combined gene dataset (CGD). CGD was used to identify differentially expressed genes (DEGs) based on a comparison of the HIRI and healthy control cohorts. The impact of these DEGs on HIRI was assessed through gene set enrichment analysis (GSEA) and gene set variation analysis (GSVA). ERGs were retrieved from the GeneCards database and prior studies, and overlapped with the identified DEGs to yield the set of exosome-related differentially expressed genes (ERDEGs). Functional annotations and enrichment pathways of these genes were determined using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses. Diagnostic models for HIRI were developed using least absolute shrinkage and selection operator (LASSO) regression and support vector machine (SVM) algorithms. Key genes with diagnostic value were identified from the overlap, and single-sample gene-set enrichment analysis (ssGSEA) was conducted to evaluate the immune infiltration characteristics. A molecular regulatory interaction network was established using Cytoscape software to elucidate the intricate regulatory mechanisms of key genes in HIRI. Finally, exosome score (Es) was obtained using ssGSEA and the HIRI group was divided into the Es_High and Es_Low groups based on the median Es. Gene expression was analyzed to understand the impact of all genes in the CGD on HIRI. Finally, the relative expression levels of the five key genes in the hypoxia-reoxygenation (H/R) model were determined using quantitative real-time PCR (qRT-PCR). A total of 3810 DEGs were identified through differential expression analysis of the CGD, and 61 of these ERDEGs were screened. Based on GO and KEGG enrichment analyses, the ERDEGs were mainly enriched in wound healing, MAPK, protein kinase B signaling, and other pathways. GSEA and GSVA revealed that these genes were mainly enriched in the TP53, MAPK, TGF[Formula: see text], JAK-STAT, MAPK, and NFKB pathways. Five key genes (ANXA1, HNRNPA2B1, ICAM1, PTEN, and THBS1) with diagnostic value were screened using the LASSO regression and SVM algorithms and their molecular interaction network was established using Cytoscape software. Based on ssGSEA, substantial variations were found in the expression of 18 immune cell types among the groups (p < 0.05). Finally, the Es of each HIRI patient was calculated. ERDEGs in the Es_High and Es_Low groups were enriched in the IL18, TP53, MAPK, TGF[Formula: see text], and JAK-STAT pathways. The differential expression of these five key genes in the H/R model was verified using qRT-PCR. Herein, five key genes were identified as potential diagnostic markers. Moreover, the potential impact of these genes on pathways and the regulatory mechanisms of their interaction network in HIRI were revealed. Altogether, our findings may serve as a theoretical foundation for enhancing clinical diagnosis and elucidating underlying pathogeneses.

Intercellular adhesion molecule-1 suppresses TMZ chemosensitivity in acquired TMZ-resistant gliomas by increasing assembly of ABCB1 on the membrane

AIMS

Despite aggressive treatment, the recurrence of glioma is an inevitable occurrence, leading to unsatisfactory clinical outcomes. A plausible explanation for this phenomenon is the phenotypic alterations that glioma cells undergo aggressive therapies, such as TMZ-therapy. However, the underlying mechanisms behind these changes are not well understood.

METHODS

The TMZ chemotherapy resistance model was employed to assess the expression of intercellular adhesion molecule-1 (ICAM1) in both in vitro and in vivo settings. The potential role of ICAM1 in regulating TMZ chemotherapy resistance was investigated through knockout and overexpression techniques. Furthermore, the mechanism underlying ICAM1-mediated TMZ chemotherapy resistance was examined using diverse molecular biological methods, and the lipid raft protein was subsequently isolated to investigate the cellular subcomponents where ICAM1 operates.

RESULTS

Acquired TMZ resistant (TMZ-R) glioma models heightened production of intercellular adhesion molecule-1 (ICAM1) in TMZ-R glioma cells. Additionally, we observed a significant suppression of TMZ-R glioma proliferation upon inhibition of ICAM1, which was attributed to the enhanced intracellular accumulation of TMZ. Our findings provide evidence supporting the role of ICAM1, a proinflammatory marker, in promoting the expression of ABCB1 on the cell membrane of TMZ-resistant cells. We have elucidated the mechanistic pathway by which ICAM1 modulates phosphorylated moesin, leading to an increase in ABCB1 expression on the membrane. Furthermore, our research has revealed that the regulation of moesin by ICAM1 was instrumental in facilitating the assembly of ABCB1 exclusively on the lipid raft of the membrane.

CONCLUSIONS

Our findings suggest that ICAM1 is an important mediator in TMZ-resistant gliomas and targeting ICAM1 may provide a new strategy for enhancing the efficacy of TMZ therapy against glioma.

Shedding Light on the Role of Exosomal PD-L1 (ExoPD-L1) in Cancer Progression: an Update

Exosomes are the primary category of extracellular vesicles (EVs), which are lipid-bilayer vesicles with biological activity spontaneously secreted from either normal or tansformed cells. They serve a crucial role for intercellular communication and affect extracellular environment and the immune system. Tumor-derived exosomes (TEXs) enclose high levels of immunosuppressive proteins, including programmed death-ligand 1 (PD-L1). PD-L1 and its receptor PD-1 act as crucial immune checkpoint molecules, thus facilitating tumor advancement by inhibiting immune responses. PDL-1 is abundantly present on tumor cells and interacts with PD-1 on activated T cells, resulting in T cell suppression and allowing immune evasion of cancer cells. Various FDA-approved monoclonal antibodies inhibiting the PD-1/PD-L1 interaction are commonly used to treat a diverse range of tumors. Although the achieved results are significant, some individuals have a poor reaction to PD-1/PD-L1 blocking. PD-L1-enriched TEXs may mimic the impact of cell-surface PD-L1, consequently potentiating tumor resistance to PD1/PD-L1 based therapy. In light of this, a strong correlation between circulating exosomal PD-L1 levels and response rate to anti-PD-1/PD-L1 antibody treatment has been evinced. This article inspects the function of exosomal PDL-1 in developing resistance to anti-PD-1/PD-L1 therapy for opening new avenues for overcoming tumor resistance to such modalities and development of more favored combination therapy.

Extracellular vesicles: A potential new way to assess cholestasis

Extracellular vesicles (EVs) are small, nonreplicating, lipid-encapsulated nanoparticles that carry protein and nucleic acid cargo derived from their tissue of origin. Due to their capacity to provide comparable insights to solid organ biopsy through a minimally invasive collection procedure, EVs provide an attractive biomarker source. This review will provide an insight, how EVs in circulation may provide a novel way to assess cholestasis and will address the possibility of getting a better understanding of the mechanisms of cholestasis of pregnancy through the use of serial hepatic-specific EVs as a window.

Exploring Unique Extracellular Vesicles Associated Signatures: Prognostic Insights, Immune Microenvironment Dynamics, and Therapeutic Responses in Pancreatic Adenocarcinoma

Extracellular vesicles play an important role in the progression of pancreatic adenocarcinoma (PAAD) through the transfer of proteins, mRNAs, and long noncoding RNAs (lncRNAs). However, the intricate interplay between extracellular vesicles-related lncRNAs and the tumor microenvironment (TME) remains poorly elucidated. Consequently, our investigation aimed to delineate the association between extracellular vesicles-related lncRNAs and the PAAD microenvironment. Initially, we identified differentially expressed lncRNAs (DELs) from The Cancer Genome Atlas (TCGA) and Genotype-Tissue Expression (GTEx) project datasets. Subsequently, we validated the expression of these DELs within extracellular vesicles and assessed their prognostic implications in PAAD using the GSE133684 and TCGA datasets. Multiomics data were analyzed comprehensively, including genomic landscape, functional annotation, immune profiles, and therapeutic responses. Differential expression of selected lncRNAs in both cellular and exosomal fractions of PAAD was further confirmed through quantitative polymerase chain reaction (qPCR). Eight DELs were identified from TCGA and GTEx datasets, and two exosomal lncRNAs exhibited a significant correlation with overall survival, warranting further investigation. Specifically, elevated expression of LINC00996 correlated positively with immune infiltration and enhanced response to immunotherapy. Conversely, heightened expression of TRHED-AS1 was associated with compromised immune cell infiltration and diminished responsiveness to immunotherapy. Our study establishes a compelling link between two extracellular vesicles-related gene signatures, prognosis, and immune infiltration in PAAD. Notably, these signatures serve as robust prognostic indicators for PAAD patients, offering valuable insights for the strategic selection of immunotherapeutic interventions.

The biology and function of extracellular vesicles in immune response and immunity

Extracellular vesicles (EVs), such as ectosomes and exosomes, contain DNA, RNA, proteins and are encased in a phospholipid bilayer. EVs provide intralumenal cargo for delivery into the cytoplasm of recipient cells with an impact on the function of immune cells, in part because their biogenesis can also intersect with antigen processing and presentation. Motile EVs from activated immune cells may increase the frequency of immune synapses on recipient cells in a proximity-independent manner for local and long-distance modulation of systemic immunity in inflammation, autoimmunity, organ fibrosis, cancer, and infections. Natural and engineered EVs exhibit the ability to impact innate and adaptive immunity and are entering clinical trials. EVs are likely a component of an optimally functioning immune system, with the potential to serve as immunotherapeutics. Considering the evolving evidence, it is possible that EVs could be the original primordial organic units that preceded the creation of the first cell.

3D-hUMSCs Exosomes Ameliorate Vitiligo by Simultaneously Potentiating Treg Cells-Mediated Immunosuppression and Suppressing Oxidative Stress-Induced Melanocyte Damage

Vitiligo is an autoimmune disease characterized by epidermal melanocyte destruction, with abnormal autoimmune responses and excessive oxidative stress as two cardinal mechanisms. Human umbilical mesenchymal stem cells-derived exosomes (hUMSCs-Exos) are regarded as promising therapeutic choice for autoimmune diseases due to potent immunosuppressive and anti-oxidative properties, which can be potentiated under 3D cell culture condition. Nevertheless, whether exosomes derived from 3D spheroids of hUMSCs (3D-Exos) exhibit considerable therapeutic effect on vitiligo and the underlying mechanism remain elusive. In this study, systemic administration of 3D-Exos showed a remarkable effect in treating mice with vitiligo, as revealed by ameliorated skin depigmentation, less CD8+T cells infiltration, and expanded Treg cells in skin, and 3D-Exos exerted a better effect than 2D-Exos. Mechanistically, 3D-Exos can prominently facilitate the expansion of Treg cells in vitiligo lesion and suppress H2O2-induced melanocytes apoptosis. Forward miRNA profile analysis and molecular experiments have demonstrated that miR-132-3p and miR-125b-5p enriched in 3D-Exos greatly contributed to these biological effects by targeting Sirt1 and Bak1 respectively. In aggregate, 3D-Exos can efficiently ameliorate vitiligo by simultaneously potentiating Treg cells-mediated immunosuppression and suppressing oxidative stress-induced melanocyte damage via the delivery of miR-132-3p and miR-125b-5p. The employment of 3D-Exos will be a promising treament for vitiligo.

Composition, functions, and applications of exosomal membrane proteins

Exosomes play a crucial role in various biological processes, such as human development, immune responses, and disease occurrence. The membrane proteins on exosomes are pivotal factors for their biological functionality. Currently, numerous membrane proteins have been identified on exosome membranes, participating in intercellular communication, mediating target cell recognition, and regulating immune processes. Furthermore, membrane proteins from exosomes derived from cancer cells can serve as relevant biomarkers for early cancer diagnosis. This article provides a comprehensive review of the composition of exosome membrane proteins and their diverse functions in the organism's biological processes. Through in-depth exploration of exosome membrane proteins, it is expected to offer essential foundations for the future development of novel biomedical diagnostics and therapies.

One-Step Formation Method of Plasmid DNA-Loaded, Extracellular Vesicles-Mimicking Lipid Nanoparticles Based on Nucleic Acids Dilution-Induced Assembly

We propose a nucleic acids dilution-induced assembly (NADIA) method for the preparation of lipid nanoparticles. In the conventional method, water-soluble polymers such as nucleic acids and proteins are mixed in the aqueous phase. In contrast, the NADIA method, in which self-assembly is triggered upon dilution, requires dispersion in an alcohol phase without precipitation. We then investigated several alcohols and discovered that propylene glycol combined with sodium chloride enabled the dispersion of plasmid DNA and protamine sulfate in the alcohol phase. The streamlined characteristics of the NADIA method enable the preparation of extracellular vesicles-mimicking lipid nanoparticles (ELNPs). Among the mixing methods using a micropipette, a syringe pump, and a microfluidic device, the lattermost was the best for decreasing batch-to-batch differences in size, polydispersity index, and transfection efficiency in HepG2 cells. Although ELNPs possessed negative ζ-potentials and did not have surface antigens, their transfection efficiency was comparable to that of cationic lipoplexes. We observed that lipid raft-mediated endocytosis and macropinocytosis contributed to the transfection of ELNPs. Our strategy may overcome the hurdles linked to supply and quality owing to the low abundance and heterogeneity in cell-based extracellular vesicles production, making it a reliable and scalable method for the pharmaceutical manufacture of such complex formulations.

Role of ICAM-1 in triple-negative breast cancer

Intercellular adhesion molecule-1 (ICAM-1) is related to the occurrence and development of a variety of tumors. However, the role of ICAM-1 in the regulation of growth, metastasis, and clinical prognosis of the specific molecular subtypes of breast cancer, triple-negative breast cancer (TNBC), remains to be elucidated. This study explored the role of ICAM-1 in breast cancer and its triple-negative subtypes by systematic bioinformatics methods. The results showed that the expression of ICAM-1 in breast cancer tissues was significantly higher than that in normal tissues, especially in TNBC subtypes. In breast cancer, ICAM-1 mainly activates pathways related to apoptosis and epithelial-mesenchymal transition, while its overexpression in TNBC is associated with inflammatory response, apoptosis, and other processes. TNBC patients displaying higher ICAM-1 expression demonstrate enhanced responses to immunotherapy. High ICAM-1 expression is sensitive to drugs targeting tumor cell proliferation, apoptosis, and angiogenesis. In conclusion, breast cancer is characterized by significantly high expression of ICAM-1, with TNBC subtypes expressing ICAM-1 at much higher levels than other subtypes. The diagnosis, prognosis, development, distant metastases, and immunotherapy of TNBC are correlated with high expression of ICAM-1. This research provides available data for the further study of the diagnosis and treatment of TNBC.

The role of extracellular vesicle immune checkpoints in cancer

Immune checkpoints (ICPs) play a crucial role in regulating the immune response. In the tumor, malignant cells can hijack the immunosuppressive effects of inhibitory ICPs to promote tumor progression. Extracellular vesicles (EVs) are produced by a variety of cells and contain bioactive molecules on their surface or within their lumen. The expression of ICPs has also been detected in EVs. In vitro and in vivo studies have shown that extracellular vesicle immune checkpoints (EV ICPs) have immunomodulatory effects and are involved in tumor immunity. EV ICPs isolated from the peripheral blood of cancer patients are closely associated with the tumor progression and the prognosis of cancer patients. Blocking inhibitory ICPs has been recognized as an effective strategy in cancer treatment. However, the efficacy of immune checkpoint inhibitors (ICIs) in cancer treatment is hindered by the emergence of therapeutic resistance, which limits their widespread use. Researchers have demonstrated that EV ICPs are correlated with clinical response to ICIs therapy and were involved in therapeutic resistance. Therefore, it is essential to investigate the immunomodulatory effects, underlying mechanisms, and clinical significance of EV ICPs in cancer. This review aims to comprehensively explore these aspects. We have provided a comprehensive description of the cellular origins, immunomodulatory effects, and clinical significance of EV ICPs in cancer, based on relevant studies.

PD-1/CD80+ small extracellular vesicles from immunocytes induce cold tumours featured with enhanced adaptive immunosuppression

Only a minority of cancer patients benefit from immune checkpoint blockade therapy. Sophisticated cross-talk among different immune checkpoint pathways as well as interaction pattern of immune checkpoint molecules carried on circulating small extracellular vesicles (sEV) might contribute to the low response rate. Here we demonstrate that PD-1 and CD80 carried on immunocyte-derived sEVs (I-sEV) induce an adaptive redistribution of PD-L1 in tumour cells. The resulting decreased cell membrane PD-L1 expression and increased sEV PD-L1 secretion into the circulation contribute to systemic immunosuppression. PD-1/CD80+ I-sEVs also induce downregulation of adhesion- and antigen presentation-related molecules on tumour cells and impaired immune cell infiltration, thereby converting tumours to an immunologically cold phenotype. Moreover, synchronous analysis of multiple checkpoint molecules, including PD-1, CD80 and PD-L1, on circulating sEVs distinguishes clinical responders from those patients who poorly respond to anti-PD-1 treatment. Altogether, our study shows that sEVs carry multiple inhibitory immune checkpoints proteins, which form a potentially targetable adaptive loop to suppress antitumour immunity.

Multi-omic features and clustering phenotypes of circulating tumor cells associated with metastasis and clinical outcomes

Metastasis is a lethal disease of cancer, spreading from primary tumors to the bloodstream as circulating tumor cells (CTCs), which disseminate to distant organs at low efficiency for secondary tumor regeneration, thereby contributing to unfavorable patient outcomes. The detection of dynamic CTC alterations can be indicative of cancer progression (residual cancer, aggressiveness, therapy resistance) or regression (therapy response), serving as biomarkers for diagnoses and prognoses. CTC heterogeneity is impacted by both intrinsic oncogenic changes and extrinsic microenvironmental factors (e.g. the immune system and circadian rhythm), altering the genomic/genetic, epigenomic/epigenetic, proteomic, post-translational, and metabolomic landscapes. In addition to homeostatic dynamics, regenerative stemness, and metabolic plasticity, a newly discovered feature of CTCs that influences metastatic outcomes is its intercellular clustering. While the dogma suggests that CTCs play solo as single cells in the circulation, CTCs can orchestrate with other CTCs or white blood cells to form homotypic or heterotypic multi-cellular clusters, with 20-100 times enhanced metastatic potential than single CTCs. CTC clusters promote cell survival and stemness through DNA hypomethylation and signaling pathways activated by clustering-driving proteins (CD44, CD81, ICAM1, Podocalyxin, etc). Heterotypic CTC clusters may protect CTCs from immune cell attacks if not being cleared by cytotoxic immune cells. This chapter mainly focused on CTC biology related to multi-omic features and metastatic outcomes. We speculate that CTCs could guide therapeutic targeting and be targeted specifically by anti-CTC therapeutics to reduce or eliminate cancer and cancer metastasis.

The emerging role of extracellular vesicles in bronchopulmonary dysplasia

Extracellular vesicle (EV) biology in neonatal lung development and disease is a rapidly growing area of investigation. Although EV research in the neonatal population lags behind EV research in adult lung diseases, recent discoveries demonstrate promise in furthering our understanding of the pathophysiology of bronchopulmonary dysplasia and the potential use of EVs in the clinical setting, as both biomarkers and therapeutic agents. This review article explores some of the recent advances in this field and our evolving knowledge of the role of EVs in bronchopulmonary dysplasia.

Treating cancer through modulating exosomal protein loading and function: The prospects of natural products and traditional Chinese medicine

Exosomes, small yet vital extracellular vesicles, play an integral role in intercellular communication. They transport critical components, such as proteins, lipid bilayers, DNA, RNA, and glycans, to target cells. These vesicles are crucial in modulating the extracellular matrix and orchestrating signal transduction processes. In oncology, exosomes are pivotal in tumor growth, metastasis, drug resistance, and immune modulation within the tumor microenvironment. Exosomal proteins, noted for their stability and specificity, have garnered widespread attention. This review delves into the mechanisms of exosomal protein loading and their impact on tumor development, with a focus on the regulatory effects of natural products and traditional Chinese medicine on exosomal protein loading and function. These insights not only offer new strategies and methodologies for cancer treatment but also provide scientific bases and directions for future clinical applications.

Dendritic cell-derived exosome (DEX) therapy for digestive system cancers: Recent advances and future prospect

Tumor-mediated immunosuppression is a fundamental obstacle to the development of dendritic cell (DC)-based cancer vaccines, which despite their ability to stimulate host anti-tumor CD8 T cell immunity, have not been able to generate meaningful therapeutic responses. Exosomes are inactive membrane vesicles that are nanoscale in size and are produced by the endocytic pathway. They are essential for intercellular communication. Additionally, DC-derived exosomes (DEXs) contained MHC class I/II (MHCI/II), which is frequently complexed with antigens and co-stimulatory molecules and is therefore able to prime CD4 and CD8 T cells that are specific to particular antigens. Indeed, vaccines with DEXs have been shown to exhibit better anti-tumor efficacy in eradicating tumors compared to DC vaccines in pre-clinical models of digestive system tumors. Also, there is room for improvement in the tumor antigenic peptide (TAA) selection process. DCs release highly targeted exosomes when the right antigenic peptide is chosen, which could aid in the creation of DEX-based antitumor vaccines that elicit more targeted immune responses. Coupled with their resistance to tumor immunosuppression, DEXs-based cancer vaccines have been heralded as the superior alternative cell-free therapeutic vaccines over DC vaccines to treat digestive system tumors. In this review, current studies of DEXs cancer vaccines as well as potential future directions will be deliberated.

Exosomal PD-L1 in cancer and other fields: recent advances and perspectives

PD-1/PD-L1 signaling is a key factor of local immunosuppression in the tumor microenvironment. Immune checkpoint inhibitors targeting PD-1/PD-L1 signaling have achieved tremendous success in clinic. However, several types of cancer are particularly refractory to the anti-PD-1/PD-L1 treatment. Recently, a series of studies reported that IFN-γ can stimulate cancer cells to release exosomal PD-L1 (exoPD-L1), which possesses the ability to suppress anticancer immune responses and is associated with anti-PD-1 response. In this review, we introduce the PD-1/PD-L1 signaling, including the so-called 'reverse signaling'. Furthermore, we summarize the immune treatments of cancers and pay more attention to immune checkpoint inhibitors targeting PD-1/PD-L1 signaling. Additionally, we review the action mechanisms and regulation of exoPD-L1. We also introduce the function of exoPD-L1 as biomarkers. Finally, we review the methods for analyzing and quantifying exoPD-L1, the therapeutic strategies targeting exoPD-L1 to enhance immunotherapy and the roles of exoPD-L1 beyond cancer. This comprehensive review delves into recent advances of exoPD-L1 and all these findings suggest that exoPD-L1 plays an important role in both cancer and other fields.

Extracellular vesicle-mediated communication between CD8+ cytotoxic T cells and tumor cells

Tumors pose a significant global public health challenge, resulting in numerous fatalities annually. CD8+ T cells play a crucial role in combating tumors; however, their effectiveness is compromised by the tumor itself and the tumor microenvironment (TME), resulting in reduced efficacy of immunotherapy. In this dynamic interplay, extracellular vesicles (EVs) have emerged as pivotal mediators, facilitating direct and indirect communication between tumors and CD8+ T cells. In this article, we provide an overview of how tumor-derived EVs directly regulate CD8+ T cell function by carrying bioactive molecules they carry internally and on their surface. Simultaneously, these EVs modulate the TME, indirectly influencing the efficiency of CD8+ T cell responses. Furthermore, EVs derived from CD8+ T cells exhibit a dual role: they promote tumor immune evasion while also enhancing antitumor activity. Finally, we briefly discuss current prevailing approaches that utilize functionalized EVs based on tumor-targeted therapy and tumor immunotherapy. These approaches aim to present novel perspectives for EV-based tumor treatment strategies, demonstrating potential for advancements in the field.

Exosomes derived from programmed cell death: mechanism and biological significance

Exosomes are nanoscale extracellular vesicles present in bodily fluids that mediate intercellular communication by transferring bioactive molecules, thereby regulating a range of physiological and pathological processes. Exosomes can be secreted from nearly all cell types, and the biological function of exosomes is heterogeneous and depends on the donor cell type and state. Recent research has revealed that the levels of exosomes released from the endosomal system increase in cells undergoing programmed cell death. These exosomes play crucial roles in diseases, such as inflammation, tumors, and autoimmune diseases. However, there is currently a lack of systematic research on the differences in the biogenesis, secretion mechanisms, and composition of exosomes under different programmed cell death modalities. This review underscores the potential of exosomes as vital mediators of programmed cell death processes, highlighting the interconnection between exosome biosynthesis and the regulatory mechanisms governing cell death processes. Furthermore, we accentuate the prospect of leveraging exosomes for the development of innovative biomarkers and therapeutic strategies across various diseases.

ICAMs in Immunity, Intercellular Adhesion and Communication

Interactions among leukocytes and leukocytes with immune-associated auxiliary cells represent an essential feature of the immune response that requires the involvement of cell adhesion molecules (CAMs). In the immune system, CAMs include a wide range of members pertaining to different structural and functional families involved in cell development, activation, differentiation and migration. Among them, β2 integrins (LFA-1, Mac-1, p150,95 and αDβ2) are predominantly involved in homotypic and heterotypic leukocyte adhesion. β2 integrins bind to intercellular (I)CAMs, actin cytoskeleton-linked receptors belonging to immunoglobulin superfamily (IgSF)-CAMs expressed by leukocytes and vascular endothelial cells, enabling leukocyte activation and transendothelial migration. β2 integrins have long been viewed as the most important ICAMs partners, propagating intracellular signalling from β2 integrin-ICAM adhesion receptor interaction. In this review, we present previous evidence from pioneering studies and more recent findings supporting an important role for ICAMs in signal transduction. We also discuss the contribution of immune ICAMs (ICAM-1, -2, and -3) to reciprocal cell signalling and function in processes in which β2 integrins supposedly take the lead, paying particular attention to T cell activation, differentiation and migration.

The ins-and-outs of exosome biogenesis, secretion, and internalization

Exosomes are specialized cargo delivery vesicles secreted from cells by fusion of multivesicular bodies (MVBs) with the plasma membrane (PM). While the function of exosomes during physiological and pathological events has been extensively reported, there remains a lack of understanding of the mechanisms that regulate exosome biogenesis, secretion, and internalization. Recent technological and methodological advances now provide details about MVB/exosome structure as well as the pathways of exosome biogenesis, secretion, and uptake. In this review, we outline our current understanding of these processes and highlight outstanding questions following on recent discoveries in the field.

Extracellular RNA in oncogenesis, metastasis and drug resistance

Extracellular vesicles and nanoparticles (EVPs) are now recognized as a novel form of cell-cell communication. All cells release a wide array of heterogeneous EVPs with distinct protein, lipid, and RNA content, dependent on the pathophysiological state of the donor cell. The overall cargo content in EVPs is not equivalent to cellular levels, implying a regulated pathway for selection and export. In cancer, release and uptake of EVPs within the tumour microenvironment can influence growth, proliferation, invasiveness, and immune evasion. Secreted EVPs can also have distant, systemic effects that can promote metastasis. Here, we review current knowledge of EVP biogenesis and cargo selection with a focus on the role that extracellular RNA plays in oncogenesis and metastasis. Almost all subtypes of RNA have been identified in EVPs, with miRNAs being the best characterized. We review the roles of specific miRNAs that have been detected in EVPs and that play a role in oncogenesis and metastasis.