Multifunctional hybrid exosomes enhanced cancer chemo-immunotherapy by activating the STING pathway

Progress of exosomes in regulating tumor metastasis by remodeling the pre-metastatic immune microenvironment

Exosomes play an important role in the metastatic microenvironment, acting as a transmission belt that facilitates intercellular communication. By delivering proteins, nucleic acids, and other substances in the exosomes, they can change the function of the receptor target cells, change the microenvironment of the metastatic site, and promote the colonization of the tumor cells, thus promoting cancer metastasis. The interaction between tumor cells and the surrounding microenvironment is complex, with exosomes serving as key facilitators of crosstalk between the primary tumor microenvironment and the pre-metastasis microenvironment. Despite many current studies to explore exosomes, we still do not have a detailed understanding of the role and mechanism of exosomes in the pre-metastatic immune microenvironment, and there are many challenges in the clinical application of exosomes. In this paper, we summarize the role of exosomes in regulating the pre-metastatic immune microenvironment and its mechanism, focusing on how exosomes regulate the function of immune cells in the pre-metastatic microenvironment to promote tumor metastasis. In addition, the potential application of exosomes in tumor immunotherapy and strategies for targeting exosomes are discussed. This will contribute to the immunotherapy of cancer metastasis and promote the clinical application of exosomes.

Advances in cancer immunotherapy: historical perspectives, current developments, and future directions

Cancer immunotherapy, encompassing both experimental and standard-of-care therapies, has emerged as a promising approach to harnessing the immune system for tumor suppression. Experimental strategies, including novel immunotherapies and preclinical models, are actively being explored, while established treatments, such as immune checkpoint inhibitors (ICIs), are widely implemented in clinical settings. This comprehensive review examines the historical evolution, underlying mechanisms, and diverse strategies of cancer immunotherapy, highlighting both its clinical applications and ongoing preclinical advancements. The review delves into the essential components of anticancer immunity, including dendritic cell activation, T cell priming, and immune surveillance, while addressing the challenges posed by immune evasion mechanisms. Key immunotherapeutic strategies, such as cancer vaccines, oncolytic viruses, adoptive cell transfer, and ICIs, are discussed in detail. Additionally, the role of nanotechnology, cytokines, chemokines, and adjuvants in enhancing the precision and efficacy of immunotherapies were explored. Combination therapies, particularly those integrating immunotherapy with radiotherapy or chemotherapy, exhibit synergistic potential but necessitate careful management to reduce side effects. Emerging factors influencing immunotherapy outcomes, including tumor heterogeneity, gut microbiota composition, and genomic and epigenetic modifications, are also examined. Furthermore, the molecular mechanisms underlying immune evasion and therapeutic resistance are analyzed, with a focus on the contributions of noncoding RNAs and epigenetic alterations, along with innovative intervention strategies. This review emphasizes recent preclinical and clinical advancements, with particular attention to biomarker-driven approaches aimed at optimizing patient prognosis. Challenges such as immunotherapy-related toxicity, limited efficacy in solid tumors, and production constraints are highlighted as critical areas for future research. Advancements in personalized therapies and novel delivery systems are proposed as avenues to enhance treatment effectiveness and accessibility. By incorporating insights from multiple disciplines, this review aims to deepen the understanding and application of cancer immunotherapy, ultimately fostering more effective and widely accessible therapeutic solutions.

Extracellular vesicles as nature's nano carriers in cancer therapy: insights toward preclinical studies and clinical applications

Extracellular vesicles (EVs), which are secreted by various cell types, hold significant potential for cancer therapy. However, there are several challenges and difficulties that limit their application in clinical settings. This review, which integrates the work of our team and recent advancements in this research field, discusses EV-based cancer treatment strategies to guide their clinical application. The following treatment strategies are discussed: 1) leveraging the inherent properties of EVs for the development of cancer treatments; 2) modifying EVs using EV engineering methods to improve drug loading and delivery; 3) targeting key molecules in tumor-derived EV (TDE) synthesis to inhibit their production; and 4) clearing TDEs from the tumor microenvironment. Additionally, on the basis of research into EV-based vaccines and bispecific antibodies, this review elaborates on strategies to enhance antitumor immunity via EVs and discusses engineering modifications that can improve EV targeting ability and stability and the research progress of AI technology in targeted delivery of EV drugs. Although there are limited strategies for enhancing EV targeting abilities, this review provides an in-depth discussion of prior studies. Finally, this review summarizes the clinical progress on the use of EVs in cancer therapy and highlights challenges that need to be addressed.

Exosome-mediated ferroptosis in the tumor microenvironment: from molecular mechanisms to clinical application

Ferroptosis in the tumor microenvironment (TME) plays a crucial role in the development, metastasis, immune escape, and drug resistance of various types of cancer. A better understanding of ferroptosis in the TME could illuminate novel aspects of this process and promote the development of targeted therapies. Compelling evidence indicates that exosomes are key mediators in regulating the TME. In this respect, it is now understood that exosomes can deliver biologically functional molecules to recipient cells, influencing cancer progression by reprogramming the metabolism of cancer cells and their surrounding stromal cells through ferroptosis. In this review, we focus on the role of exosomes in the TME and describe how they contribute to tumor reprogramming, immunosuppression, and the formation of pre-metastatic niches through ferroptosis. In addition, we highlight exosome-mediated ferroptosis as a potential target for cancer therapy and discuss strategies employing exosomes in ferroptosis treatment. Finally, we outline the current applications and challenges of targeted exosome-mediated ferroptosis therapy in tumor immunotherapy and chemotherapy. Our aim is to advance research on the link between exosomes and ferroptosis in the TME, and we pose questions to guide future studies in this area.

Harnessing engineered extracellular vesicles for enhanced therapeutic efficacy: advancements in cancer immunotherapy

Extracellular vesicles (EVs), particularly engineered variants, have emerged as promising tools in cancer immunotherapy due to their inherent ability to modulate immune responses and deliver therapeutic agents with high specificity and minimal toxicity. These nanometer-sized vesicles, which include exosomes (Exos) and other subtypes, naturally participate in intercellular communication and are capable of carrying a diverse range of bioactive molecules, including proteins, lipids, RNAs, and metabolites. Recent advancements in the biogenesis of engineered EVs, such as strategies to modify their surface characteristics and cargo, have significantly expanded their potential as effective vehicles for targeted cancer therapies. Tailoring the contents of EVs, such as incorporating immunomodulatory molecules or gene-editing tools (GETs), has shown promising outcomes in enhancing anti-tumor immunity and overcoming the immunosuppressive tumor microenvironment (TME). Moreover, optimizing delivery mechanisms, through both passive and active targeting strategies, is crucial for improving the clinical efficacy of EV-based therapies. This review provides an overview of recent developments in the engineering of EVs for cancer immunotherapy, focusing on their biogenesis, methods of content customization, and innovations in cargo delivery. Additionally, the review addresses the challenges associated with the clinical translation of EV-based therapies, such as issues related to scalability, safety, and targeted delivery. By offering insights into the current state of the field and identifying key areas for future research, this review aims to advance the application of engineered EVs in cancer treatment.

The latest applications of exosome-mediated drug delivery in anticancer therapies

In recent years, the significant role of anticancer drugs in cancer treatment has garnered considerable attention. However, the application of these drugs is largely limited by their short half-life in blood circulation, low cellular uptake efficiency, and off-target effects. Exosomes, which serve as crucial messengers in intercellular communication, exhibit unique advantages in molecular delivery compared to traditional synthetic carriers, thereby offering new possibilities for modern drug delivery systems. Exosomes possess organotropic functions and are naturally produced by cells, making them promising candidates for natural drug delivery systems with organotropic properties and minimal side effects. These naturally derived carriers can achieve stable, efficient, and selective delivery of anticancer drugs, thereby enhancing the efficacy and potential of anticancer agents in cancer immunotherapy. This review provides a concise overview of the unique characteristics of exosomes related to anticancer drug delivery, strategies for utilizing exosomes as carriers in cancer therapy, and the latest advancements in the field.

Enhancing nano-immunotherapy of cancer through cGAS-STING pathway modulation

Activation of the cyclic guanosine monophosphate-adenosine monophosphate synthase (cGAS)-stimulator of interferon genes (STING) pathway plays a critical role in cancer immunotherapy due to the secretion of multiple pro-inflammatory cytokines and chemokines. Numerous cGAS-STING agonists have been developed for preclinical and clinical trials in tumor immunity. However, several obstacles, such as agonist molecules requiring multiple doses, rapid degradation and poor targeting, weaken STING activation at the tumor site. The advancement of nanotechnology provides an optimized platform for the clinical application of STING agonists. In this review, we summarize events of cGAS-STING pathway activation, the dilemma of delivering STING agonists, and recent advances in the nano-delivery of cGAS-STING agonist formulations for enhancing tumor immunity. Furthermore, we address the future challenges associated with STING-based therapies and offer insights to guide subsequent clinical applications.

Macrophage-derived exosomes in cancer: a double-edged sword with therapeutic potential

Solid cancer contains a complicated communication network between cancer cells and components in the tumor microenvironment (TME), significantly influencing the progression of cancer. Exosomes function as key carriers of signaling molecules in these communications, including the intricate signalings of tumor-associated macrophages (TAMs) on cancer cells and the TME. With their natural lipid bilayer structures and biological activity that relates to their original cell, exosomes have emerged as efficient carriers in studies on cancer therapy. Intrigued by the heterogeneity and plasticity of both macrophages and exosomes, we regard macrophage-derived exosomes in cancer as a double-edged sword. For instance, TAM-derived exosomes, educated by the TME, can promote resistance to cancer therapies, while macrophage-derived exosomes generated in vitro have shown favorable potential in cancer therapy. Here, we depict the reasons for the heterogeneity of TAM-derived exosomes, as well as the manifold roles of TAM-derived exosomes in cancer progression, metastasis, and resistance to cancer therapy. In particular, we emphasize the recent advancements of modified macrophage-derived exosomes in diverse cancer therapies, arguing that these modified exosomes are endowed with unique advantages by their macrophage origin. We outline the challenges in translating these scientific discoveries into clinical cancer therapy, aiming to provide patients with safe and effective treatments.

Small extracellular vesicles: the origins, current status, future prospects, and applications

Small extracellular vesicles (sEVs) are membrane-bound vesicles with a size of less than 200 nm, released by cells. Due to their relatively small molecular weight and ability to participate in intercellular communication, sEVs can serve not only as carriers of biomarkers for disease diagnosis but also as effective drug delivery agents. Furthermore, these vesicles are involved in regulating the onset and progression of various diseases, reflecting the physiological and functional states of cells. This paper introduces the classification of extracellular vesicles, with a focus on the extraction and identification of sEVs and their significant role in repair, diagnosis, and intercellular communication. Additionally, the paper addresses the engineering modification of sEVs to provide a reference for enhanced understanding and application.

Nanoimmunotherapy: the smart trooper for cancer therapy

Immunotherapy has gathered significant attention and is now a widely used cancer treatment that uses the body's immune system to fight cancer. Despite initial successes, its broader clinical application is hindered by limitations such as heterogeneity in patient response and challenges associated with the tumor immune microenvironment. Recent advancements in nanotechnology have offered innovative solutions to these barriers, providing significant enhancements to cancer immunotherapy. Nanotechnology-based approaches exhibit multifaceted mechanisms, including effective anti-tumor immune responses during tumorigenesis and overcoming immune suppression mechanisms to improve immune defense capacity. Nanomedicines, including nanoparticle-based vaccines, liposomes, immune modulators, and gene delivery systems, have demonstrated the ability to activate immune responses, modulate tumor microenvironments, and target specific immune cells. Success metrics in preclinical and early clinical studies, such as improved survival rates, enhanced tumor regression, and elevated immune activation indices, highlight the promise of these technologies. Despite these achievements, several challenges remain, including scaling up manufacturing, addressing off-target effects, and navigating regulatory complexities. The review emphasizes the need for interdisciplinary approaches to address these barriers, ensuring broader clinical adoption. It also provides insights into interdisciplinary approaches, advancements, and the transformative potential of nano-immunotherapy and promising results in checkpoint inhibitor delivery, nanoparticle-mediated photothermal therapy, immunomodulation as well as inhibition by nanoparticles and cancer vaccines.

Extracellular Vesicle-Based Antitumor Nanomedicines

Extracellular vesicles (EVs) have emerged as promising bioactive carriers for delivering therapeutic agents, including nucleic acids, proteins, and small-molecule drugs, owing to their excellent physicochemical stability and biocompatibility. However, comprehensive reviews on the various types of EV-based nanomedicines for cancer therapy remain scarce. This review explores the potential of EVs as antitumor nanomedicines. Methods for EV extraction, drug loading, and engineering modifications are systematically examined, and the strengths and limitations of these technical approaches are critically assessed. Additionally, key strategies for developing EV-based antitumor therapies are highlighted. Finally, the opportunities and challenges associated with advancing EVs toward clinical translation are discussed. With the integration of multiple disciplines, robust EV-based therapeutic platforms are expected to be manufactured to provide more personalized and effective solutions for oncology patients.

Advances in tumor immunotherapy targeting macrophages

INTRODUCTION

In recent years, immunotherapy has shown significant therapeutic potential in patients with advanced tumors. However, only a small number of individuals benefit, mainly due to the tumor microenvironment (TME), which provides conditions for the development of tumors. Macrophages in TME, known as tumor-associated macrophages (TAM), are mainly divided into M1 anti-tumor and M2 pro-tumor phenotypes, which play a regulatory role in various stages of tumorigenesis, promote tumorigenesis and metastasis, and cause immunotherapy resistance.

AREAS COVERED

This review focuses on research strategies and preclinical/clinical research progress in translating TAM into antitumor phenotype by referring to the PubMed database for five years. These include small molecule chemotherapy drug development, metabolic regulation, gene editing, physical stimulation, nanotechnology-mediated combination therapy strategies, and chimeric antigen receptor-based immunotherapy.

EXPERT OPINION

It is necessary to explore the surface-specific receptors and cell signaling pathways of TAM further to improve the specificity and targeting of drugs and to strengthen research in the field of probes that can monitor changes in TAM in real time. In addition, the physical stimulation polarization strategy has the advantages of being noninvasive, economical, and stable and will have excellent clinical transformation value in the future.

Mechanisms and Applications of Manganese-Based Nanomaterials in Tumor Diagnosis and Therapy

Tumors are the second most common cause of mortality globally, ranking just below heart disease. With continuous advances in diagnostic technology and treatment approaches, the survival rates of some cancers have increased. Nevertheless, due to the complexity of the mechanisms underlying tumors, cancer remains a serious public health issue that threatens the health of the population globally. Manganese (Mn) is an essential trace element for the human body. Its regulatory role in tumor biology has received much attention in recent years. Developments in nanotechnology have led to the emergence of Mn-based nanoparticles that have great potential for use in the diagnosis and treatment of cancers. Mn-based nanomaterials can be integrated with conventional techniques, including chemotherapy, radiation therapy, and gene therapy, to augment their therapeutic effectiveness. Further, Mn-based nanomaterials can play a synergistic role in emerging treatment strategies for tumors, such as immunotherapy, photothermal and photodynamic therapy, electromagnetic hyperthermia, sonodynamic therapy, chemodynamic therapy, and intervention therapy. Moreover, Mn-based nanomaterials can enhance both the precision of tumor diagnostics and the capability for combined diagnosis and treatment. This article examines the roles and associated mechanisms of Mn in the field of physiology and tumor biology, with a focus on the application prospects of Mn-based nanomaterials in tumor diagnosis and treatment.

Application of nanoparticles with activating STING pathway function in tumor synergistic therapy

Although immunotherapy is currently one of the most promising methods for cancer treatment, its clinical application is limited due to issues such as excessive autoimmune responses and lack of specificity. Therefore, there is a need to improve immunotherapy by integrating emerging medical technologies with traditional treatments. The activation of the cGAS-STING pathway plays a crucial role in innate immunity and antiviral defense, making it highly promising for immunotherapy and attracting significant attention. In recent years, research on nanomaterials and immunotherapy has achieved groundbreaking progress in the medical field. Due to their unique size, shape, stiffness, surface effects, and quantum size effects, nanomaterials can either carry STING activators or directly activate the STING pathway, offering new opportunities for tumor-specific immunotherapy. These unique advantages of nanomaterials have opened up broader prospects for nanoparticle-based therapies targeting the STING pathway. This paper summarizes the current research on utilizing nanomaterials to activate the STING pathway, detailing the characteristics, classifications, and different approaches for targeting tumor cells. Additionally, it focuses on the latest advancements in combined nanotherapies based on cGAS-STING pathway activation, including the integration of nanomaterial-mediated STING pathway activation with immunotherapy, radiotherapy, chemotherapy, targeted therapy, and photodynamic therapy. This provides new ideas for nanoparticle-based combination therapies involving the STING pathway.

Napabucasin deactivates STAT3 and promotes mitoxantrone-mediated cGAS-STING activation for hepatocellular carcinoma chemo-immunotherapy

The immune resistance of tumor microenvironment (TME) causes immune checkpoint blockade therapy inefficient to hepatocellular carcinoma (HCC). Emerging strategies of using chemotherapy regimens to reverse the immune resistance provide the promise for promoting the efficiency of immune checkpoint inhibitors. The induction of cyclic guanosine monophosphate-adenosine monophosphate synthase (cGAS)-stimulator of interferon genes (STING) in tumor cells evokes the adaptive immunity and remodels the immunosuppressive TME. In this study, we report that mitoxantrone (MIT, a chemotherapeutic drug) activates the cGAS-STING signaling pathway of HCC cells. We provide an approach to augment the efficacy of MIT using a signal transducer and activator of transcription 3 (STAT3) inhibitor called napabucasin (NAP). We prepare an aminoethyl anisamide (AEAA)-targeted polyethylene glycol (PEG)-modified poly (lactic-co-glycolic acid) (PLGA)-based nanocarrier for co-delivery of MIT and NAP. The resultant co-nanoformulation can elicit the cGAS-STING-based immune responses to reshape the immunoresistant TME in the mice orthotopically grafted with HCC. Consequently, the resultant co-nanoformulation can promote anti-PD-1 antibody for suppressing HCC development, generating long-term survival, and inhibiting tumor recurrence. This study reveals the potential of MIT to activate the cGAS-STING signaling pathway, and confirms the feasibility of nano co-delivery for MIT and NAP on achieving HCC chemo-immunotherapy.

Exosomes as a Therapeutic Strategy in Cancer: Potential Roles as Drug Carriers and Immune Modulators

Exosome-based cancer immunotherapy is advancing quickly on the concept of artificially activating the immune system to combat cancer. They can mechanistically change the tumor microenvironment, increase immune responses, and function as efficient drug delivery vehicles because of their inherent bioactivity, low toxicity, and immunogenicity. Accurate identification of the mechanisms of action of exosomes in tumor environments, along with optimization of their isolation, purification, and characterization methods, is necessary to increase clinical applications. Exosomes can be modified through cargo loading and surface modification to enhance their therapeutic applications, either before or after the donor cells' isolation. These engineered exosomes can directly target tumor cells at the tumor site or indirectly activate innate and adaptive immune responses in the tumor microenvironment. This approach is particularly effective when combined with traditional cancer immunotherapy techniques such as vaccines, immune checkpoints, and CAR-T cells. It can improve anti-tumor responses, induce long-term immunity, and address the limitations of traditional therapies, such as poor penetration in solid tumors and immunosuppressive environments. This review aims to provide a comprehensive and detailed overview of the direct role of engineered exosomes as drug delivery systems and their immunomodulatory effects on tumors as an indirect approach to fighting cancer. Additionally, it will discuss novel immunotherapy options.

The functional regulation between extracellular vesicles and the DNA damage responses

The DNA damage response (DDR) is a crucial regulatory mechanism for the survival of organisms, and irregularity of DDR may contribute to the development of various diseases, including tumors, making it is a prominent topic in therapeutic research. Extracellular vesicles (EVs), as important mediators of intercellular communication, have been extensively studied in recent years. Notably, an increasing number of studies have revealed a strong connection between DDR and EVs. On one hand, DNA damage affects the release of EVs and their compositional content; on the other hand, EVs can dictate cell survival or death by modulating DDR in both the parental and the recipient cells. This review outlines current progress in the inter-regulatory relationship between EVs and DDR, with special emphasis on the effects of EVs derived from various sources on DDR in recipient cells. In addition, the potential applications of EVs in research and tumor therapy are discussed.

Manganese-coordinated nanoparticle with high drug-loading capacity and synergistic photo-/immuno-therapy for cancer treatments

Stimulator of interferon genes (STING) agonists have shown promise in cancer treatment by stimulating the innate immune response, yet their clinical potential has been limited by inefficient cytosolic entry and unsatisfactory pharmacological activities. Moreover, aggressive tumors with "cold" and immunosuppressive microenvironments may not be effectively suppressed solely through innate immunotherapy. Herein, we propose a multifaceted immunostimulating nanoparticle (Mn-MC NP), which integrates manganese II (Mn2+) coordinated photosensitizers (chlorin e6, Ce6) and STING agonists (MSA-2) within a PEGylated nanostructure. In Mn-MC NPs, Ce6 exerts potent phototherapeutic effects, facilitating tumor ablation and inducing immunogenic cell death to elicit robust adaptive antitumor immunity. MSA-2 activates the STING pathway powered by Mn2+, thereby promoting innate antitumor immunity. The Mn-MC NPs feature a high drug-loading capacity (63.42 %) and directly ablate tumor tissue while synergistically boosting both adaptive and innate immune responses. In subsutaneous tumor mouse models, the Mn-MC NPs exhibit remarkable efficacy in not only eradicating primary tumors but also impeding the progression of distal and metastatic tumors through synergistic immunotherapy. Additionally, they contribute to preventing tumor recurrence by fostering long-term immunological memory. Our multifaceted immunostimulating nanoparticle holds significant potential for overcoming limitations associated with insufficient antitumor immunity and ineffective cancer treatment.

Targeted delivery of extracellular vesicles: the mechanisms, techniques and therapeutic applications

Extracellular vesicles (EVs) are cell-derived vesicles with a phospholipid bilayer measuring 50-150 nm in diameter with demonstrated therapeutic potentials. Limitations such as the natural biodistribution (mainly concentrated in the liver and spleen) and short plasma half-life of EVs present significant challenges to their clinical translation. In recent years, growing research indicated that engineered EVs with enhanced targeting to lesion sites have markedly promoted therapeutic efficacy. However, there is a dearth of systematic knowledge on the recent advances in engineering EVs for targeted delivery. Herein, we provide an overview of the targeting mechanisms, engineering techniques, and clinical translations of natural and engineered EVs in therapeutic applications. Enrichment of EVs at lesion sites may be achieved through the recognition of tissue markers, pathological changes, and the circumvention of mononuclear phagocyte system (MPS). Alternatively, external stimuli, including magnetic fields and ultrasound, may also be employed. EV engineering techniques that fulfill targeting functions includes genetic engineering, membrane fusion, chemical modification and physical modification. A comparative statistical analysis was conducted to elucidate the discrepancies between the diverse techniques on size, morphology, stability, targeting and therapeutic efficacy in vitro and in vivo. Additionally, a summary of the registered clinical trials utilizing EVs from 2010 to 2023 has been provided, with a full discussion on the perspectives. This review provides a comprehensive overview of the mechanisms and techniques associated with targeted delivery of EVs in therapeutic applications to advocate further explorations of engineered EVs and accelerate their clinical applications.

The Role of STING-Mediated Activation of Dendritic Cells in Cancer Immunotherapy

The signaling pathway that comprises cyclic guanosine monophosphate-adenosine monophosphate (cGAMP or GMP-AMP) synthase (cGAS) and Stimulator of Interferon Genes (STING) is emerging as a druggable target for immunotherapy, with tumor-resident dendritic cells (DC) playing a critical role in mediating its effects. The STING receptor is part of the DNA-sensing cellular machinery, that can trigger the secretion of pro-inflammatory mediators, priming effector T cells and initiating specific antitumor responses. Yet, recent studies have highlighted the dual role of STING activation in the context of cancer: STING can either promote antitumor responses or enhance tumor progression. This dichotomy often depends on the cell type in which cGAS-STING signaling is induced and the activation mode, namely acute versus chronic. Of note, STING activation at the DC level appears to be particularly important for tumor eradication. This review outlines the contribution of the different conventional and plasmacytoid DC subsets and describes the mechanisms underlying STING-mediated activation of DCs in cancer. We further highlight how the STING pathway plays an intricate role in modulating the function of DCs embedded in tumor tissue. Additionally, we discuss the strategies being employed to harness STING activation for cancer treatment, such as the development of synthetic agonists and nano-based delivery systems, spotlighting the current techniques used to prompt STING engagement specifically in DCs.

Co-delivery of SN38 and MEF2D-siRNA via tLyp-1-modified liposomes reverses PD-L1 expression induced by STING activation in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) exhibits an immunosuppressive tumor microenvironment, leading to a low objective response rate when immune checkpoint inhibitors (ICIs) are utilized. The cGAS-STING pathway demonstrates a powerful immune stimulatory effect, nevertheless, activation of this pathway triggers an upregulation of PD-L1, which inhibits the anti-tumor function of immune cells. The present study discovered that knockdown of MEF2D by a siRNA in H22 cells decreases the expression of PD-L1. Subsequently, tLyp-1-modified liposomes were developed for the delivery of SN38 and MEF2D-siRNA. The outcomes indicated that the modification of tLyp-1 could enhance the uptake of liposomes by tumor cells. tLip/siMEF2D/SN38 liposomes can effectively knockdown the expression of MEF2D in HCC cells and reduce the expression of PD-L1 in vitro and in vivo, thereby enhancing proliferation inhibition and apoptosis induction, and effectively suppressing the growth of tumors. SN38 treatment elevated the expression of p-TBK1 and p-IRF3 in tumor tissue, signifying the activation of the cGAS-STING pathway and facilitating the maturation of dendritic cells in vitro and in vivo. At the same time, the co-delivery of MEF2D-siRNA reduced the expression of PD-L1, thereby decreasing the quantity of M2 macrophages and myeloid-derived suppressor cells (MDSCs) in tumors, increasing the number of CD4+ T cells within the tumor, and strengthening the anti-tumor immune efficacy. In conclusion, our results suggest that tLyP-1 modified, SN38- and MEF2D siRNA-loaded liposomes have the potential for the treatment of HCC and optimize the immunotherapy of HCC via STING activation.

Targeting STING signaling for the optimal cancer immunotherapy

Despite the transformative impact of anti-PD-1/PD-L1 therapies, challenges such as low response rates persist. The stimulator of interferon genes (STING) pathway, a crucial element of innate immunity, emerges as a strategic target to overcome these limitations. Understanding its multifaceted functions in cancer, including antigen presentation and response to DNA damage, provides valuable insights. STING agonists, categorized into cyclic dinucleotides (CDNs) and non-CDNs, exhibit promising safety and efficacy profiles. Innovative delivery systems, including antibody-drug conjugates, nanocarriers, and exosome-based therapies, address challenges associated with systemic administration and enhance targeted tumor delivery. Personalized vaccines, such as DT-Exo-STING, showcase the adaptability of STING agonists for individualized treatment. These advancements not only offer new prospects for combination therapies but also pave the way for overcoming resistance mechanisms. This review focuses on the potential of targeting STING pathway to enhance cancer immunotherapy. The integration of STING agonists into cancer immunotherapy holds promise for more effective, personalized, and successful approaches against malignancies, presenting a beacon of hope for the future of cancer treatment.

Immune modulation of the liver metastatic colorectal cancer microenvironment via the oral CAPOX-mediated cGAS-STING pathway

We evaluated modulation of the immunosuppressive tumor microenvironment in both local and liver metastatic colorectal cancer (LMCC), focusing on tumor-associated macrophages, which are the predominant immunosuppressive cells in LMCC. We developed an orally administered metronomic chemotherapy regimen, oral CAPOX. This regimen combines capecitabine and a nano-micelle encapsulated, lysine-linked deoxycholate and oxaliplatin complex (OPt/LDC-NM). The treatment effectively modulated immune cells within the tumor microenvironment by activating the cGAS-STING pathway and inducing immunogenic cell death. This therapy modulated immune cells more effectively than did capecitabine monotherapy, the current standard maintenance chemotherapy for colorectal cancer. The macrophage-modifying effect of oral CAPOX was mediated via the cGAS-STING pathway. This is a newly identified mode of immune cell activation induced by metronomic chemotherapy. Moreover, oral CAPOX synergized with anti-PD-1 antibody (αPD-1) to enhance the T-cell-mediated antitumor immune response. In the CT26. CL25 subcutaneous model, combination therapy achieved a 91 % complete response rate with a confirmed memory effect against the tumor. This combination also altered the immunosuppressive tumor microenvironment in LMCC, which αPD-1 monotherapy could not achieve. Oral CAPOX and αPD-1 combination therapy outperformed the maximum tolerated dose for treating LMCC, suggesting metronomic therapy as a promising strategy.

Basic Guide for Approaching Drug Delivery with Extracellular Vesicles

Extracellular vesicles (EVs) are natural carriers of biomolecules that play a crucial role in cell-to-cell communication and tissue homeostasis under normal and pathological conditions, including inflammatory diseases and cancer. Since the discovery of the pro-regenerative and immune-modulating properties of EVs, EV-based therapeutics have entered clinical trials for conditions such as myocardial infarction and autoimmune diseases, among others. Due to their unique advantages-such as superior bioavailability, substantial packaging capacity, and the ability to traverse biological barriers-EVs are regarded as a promising platform for targeted drug delivery. However, achieving a sufficient accumulation of therapeutic agents at the target site necessitates a larger quantity of EVs per dose compared to using EVs as standalone drugs. This challenge can be addressed by administering larger doses of EVs, increasing the drug dosage per administration, or enhancing the selective accumulation of EVs at target cells. In this review, we will discuss methods to improve the isolation and purification of EVs, approaches to enhance cargo packaging-including proteins, RNAs, and small-molecule drugs-and technologies for displaying targeting ligands on the surface of EVs to facilitate improved targeting. Ultimately, this guide can be applied to the development of novel classes of EV-based therapeutics and to overcoming existing technological challenges.

Bone-targeting engineered milk-derived extracellular vesicles for MRI-assisted therapy of osteoporosis

The imbalance between osteoblasts and osteoclasts is the cause of osteoporosis. Milk-derived extracellular vesicles (mEVs), excellent drug delivery nanocarriers, can promote bone formation and inhibit bone resorption. In this study, we conjugated bone-targeting peptide (AspSerSer, DSS)6 to mEVs by click chemistry and then loaded with SRT2104, a SIRT1 (silent mating-type information regulation 2 homolog 1) agonist that was proofed to help reduce bone loss. The engineered (DSS)6-mEV-SRT2104 had the intrinsic anti-osteoporosis function of mEVs and SRT2104 to reverse the imbalance in bone homeostasis by simultaneously regulating osteogenesis and osteoclastogenesis. Furthermore, we labelled mEVs with MnB nanoparticles that can be used for the in vivo magnetic resonance imaging (MRI) visualization. The obtained nanocomposites significantly prevented bone loss in osteoporosis mice and increased bone mineral density, exhibiting superior bone accumulation under MRI. We believe the proposed (DSS)6-mEV-SRT2104/MnB provides a novel paradigm for osteoporosis treatment and monitoring.

Exosome-based anticancer vaccines: From Bench to bedside

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

Unlocking the power of nanomedicine: Cell membrane-derived biomimetic cancer nanovaccines for cancer treatment

Over the past decades, nanomedicine researchers have dedicated their efforts to developing nanoscale platforms capable of more precisely delivering drug payloads to attack tumors. Cancer nanovaccines are exhibiting a distinctive capability in inducing tumor-specific antitumor responses. Nevertheless, there remain numerous challenges that must be addressed for cancer nanovaccines to evoke sufficient therapeutic effects. Cell membrane-derived nanovaccines are an emerging class of cancer vaccines that comprise a synthetic nanoscale core camouflaged by naturally derived cell membranes. The specific cell membrane has a biomimetic nanoformulation with several distinctive abilities, such as immune evasion, enhanced biocompatibility, and tumor targeting, typically associated with a source cell. Here, we discuss the advancements of cell membrane-derived nanovaccines and how these vaccines are used for cancer therapeutics. Translational endeavors are currently in progress, and additional research is also necessary to effectively address crucial areas of demand, thereby facilitating the future successful translation of these emerging vaccine platforms.

The cGAS/STING Pathway-A New Potential Biotherapeutic Target for Gastric Cancer?

Gastric cancer ranks among the top five deadliest tumors worldwide, both in terms of prevalence and mortality rates. Despite mainstream treatments, the efficacy in treating gastric cancer remains suboptimal, underscoring the urgency for novel therapeutic approaches. The elucidation of tumor immunosuppressive microenvironments has shifted focus towards cancer biotherapeutics, which leverage the patient's immune system or biologics to target tumor cells. Biotherapy has emerged as a promising alternative for tumors resistant to traditional chemotherapy, radiation, and immunotherapy. Central to this paradigm is the cGAS-STING pathway, a pivotal component of the innate immune system. This pathway recognizes aberrant DNA, such as that from viral infections or tumor cells, and triggers an immune response, thereby reshaping the immunosuppressive tumor microenvironment into an immune-stimulating milieu. In the context of gastric cancer, harnessing the cGAS-STING pathway holds significant potential for biotherapeutic interventions. This review provides a comprehensive overview of the latest research on cGAS-STING in gastric cancer, including insights from clinical trials involving STING agonists. Furthermore, it assesses the prospects of targeting the cGAS-STING pathway as a novel biotherapeutic strategy for gastric cancer.

Metal-Free Atom Transfer Radical Polymerization to Prepare Recylable Micro-Adjuvants for Dendritic Cell Vaccine

In the development of dendritic cell (DC) vaccines, the maturation of DCs is a critical stage. Adjuvants play a pivotal role in the maturation of DCs, with a major concern being to ensure both efficacy and safety. This study introduces an innovative approach that combines high efficacy with safety through the synthesis of micro-adjuvants grafted with copolymers of 2-(methacrylamido) glucopyranose (MAG) and methacryloxyethyl trimethyl ammonium chloride (DMC). The utilization of metal-free surface-initiated atom transfer radical polymerization enables the production of safe and recyclable adjuvants. These micrometer-sized adjuvants surpass the optimal size range for cellular endocytosis, enabling the retrieval and reuse of them during the ex vivo maturation process, mitigating potential toxicity concerns associated with the endocytosis of non-metabolized nanoparticles. Additionally, the adjuvants exhibit a "micro-ligand-mediated maturation enhancement" effect for DC maturation. This effect is influenced by the shape of the particle, as evidenced by the distinct promotion effects of rod-like and spherical micro-adjuvants with comparable sizes. Furthermore, the porous structure of the adjuvants enables them to function as cargo-carrying "micro-shuttles", releasing antigens upon binding to DCs to facilitate efficient antigen delivery.

In Situ Sprayed Exosome-Cross-Linked Gel as Artificial Lymph Nodes for Postoperative Glioblastoma Immunotherapy

One key challenge in postoperative glioblastoma immunotherapy is to guarantee a potent and durable T-cell response, which is restricted by the immunosuppressive microenvironment within the lymph nodes (LNs). Here, we develop an in situ sprayed exosome-cross-linked gel that acts as an artificial LN structure to directly activate the tumor-infiltrating T cells for prevention of glioma recurrence. Briefly, this gel is generated by a bio-orthogonal reaction between azide-modified chimeric exosomes and alkyne-modified alginate polymers. Particularly, these chimeric exosomes are generated from dendritic cell (DC)-tumor hybrid cells, allowing for direct and robust T-cell activation. The gel structure with chimeric exosomes as cross-linking points avoids the quick clearance by the immune system and thus prolongs the durability of antitumor T-cell immunity. Importantly, this exosome-containing immunotherapeutic gel provides chances for ameliorating functions of antigen-presenting cells (APCs) through accommodating different intracellular-acting adjuvants, such as stimulator of interferon genes (STING) agonists. This further enhances the antitumor T-cell response, resulting in the almost complete elimination of residual lesions after surgery. Our findings provide a promising strategy for postsurgical glioma immunotherapy that warrants further exploration in the clinical arena.

Nanoparticles in tumor microenvironment remodeling and cancer immunotherapy

Cancer immunotherapy and vaccine development have significantly improved the fight against cancers. Despite these advancements, challenges remain, particularly in the clinical delivery of immunomodulatory compounds. The tumor microenvironment (TME), comprising macrophages, fibroblasts, and immune cells, plays a crucial role in immune response modulation. Nanoparticles, engineered to reshape the TME, have shown promising results in enhancing immunotherapy by facilitating targeted delivery and immune modulation. These nanoparticles can suppress fibroblast activation, promote M1 macrophage polarization, aid dendritic cell maturation, and encourage T cell infiltration. Biomimetic nanoparticles further enhance immunotherapy by increasing the internalization of immunomodulatory agents in immune cells such as dendritic cells. Moreover, exosomes, whether naturally secreted by cells in the body or bioengineered, have been explored to regulate the TME and immune-related cells to affect cancer immunotherapy. Stimuli-responsive nanocarriers, activated by pH, redox, and light conditions, exhibit the potential to accelerate immunotherapy. The co-application of nanoparticles with immune checkpoint inhibitors is an emerging strategy to boost anti-tumor immunity. With their ability to induce long-term immunity, nanoarchitectures are promising structures in vaccine development. This review underscores the critical role of nanoparticles in overcoming current challenges and driving the advancement of cancer immunotherapy and TME modification.

Cancer diagnosis and treatment platform based on manganese-based nanomaterials

Cancer is a leading cause of death worldwide, and the development of new diagnostic and treatment methods is crucial. Manganese-based nanomaterials (MnNMs) have emerged as a focal point in the field of cancer diagnosis and treatment due to their multifunctional properties. These nanomaterials have been extensively explored as contrast agents for various imaging technologies such as magnetic resonance imaging (MRI), photoacoustic imaging (PAI), and near-infrared fluorescence imaging (NIR-FL). The use of these nanomaterials has significantly enhanced the contrast for precise tumor detection and localization. Moreover, MnNMs have shown responsiveness to the tumor microenvironment (TME), enabling innovative approaches to cancer treatment. This review provides an overview of the latest developments of MnNMs and their potential applications in tumor diagnosis and therapy. Finally, potential challenges and prospects of MnNMs in clinical applications are discussed. We believe that this review would serve as a valuable resource for guiding further research on the application of manganese nanomaterials in cancer diagnosis and treatment, addressing the current limitations, and proposing future research directions.

Recent advances in extracellular vesicle engineering and its applications to regenerative medicine

Extracellular vesicles (EVs) are nanosized particles that are released from cells and reflect the characteristics of the mother cell. Recently, the EVs have been used in several types of studies across many different fields. In the field of EV research, multiple cell culture and EV isolation techniques have been highlighted in importance. Various strategies, including exclusive component culture media, three-dimensional (3D) cultures, and hypoxic conditions, have been proposed for the cell culture to control function of the EVs. Ultracentrifugation, ultrafiltration, precipitation, and tangential flow filtration (TFF) have been utilized for EV isolation. Although isolated EVs have their own functionalities, several researchers are trying to functionalize EVs by applying various engineering approaches. Gene editing, exogenous, endogenous, and hybridization methods are the four well-known types of EV functionalization strategies. EV engineered through these processes has been applied in the field of regenerative medicine, including kidney diseases, osteoarthritis, rheumatoid arthritis, nervous system-related diseases, and others. In this review, it was focused on engineering approaches for EV functionalization and their applications in regenerative medicine.