Tumor-derived microparticles promote the progression of triple-negative breast cancer via PD-L1-associated immune suppression

Irradiated tumor cell-released microparticles enhance the therapeutic efficacy of PD-1 inhibitors by promoting M1-TAMs polarization in NSCLC brain metastases

Brain metastases (BMs) are the most common sites of metastasis in patients with non-small cell lung cancer (NSCLC). However, BMs are not responsive to immunotherapy because of the blood-brain barrier. This is because intracranial immune cells such as M2 tumor-associated macrophages (TAMs) accumulate, creating an immunosuppressive tumor microenvironment. In this study, we focused on irradiated tumor cell-released microparticles (RT-MPs) that can cross the blood-brain barrier and influence the intracranial immune microenvironment. Using animal models of BMs, we observed that RT-MPs could penetrate the blood-brain barrier and be swallowed by TAMs. Then the microenvironment of TAMs is shifted from the M2 phenotype to the M1 phenotype, thereby modulating the interactions between TAMs and tumor cells. Single-cell sequencing analysis demonstrated that TAMs, after internalizing RT-MPs, active chemokine signaling pathways and secrete more chemokines, such as CCL5, CXCL2, CXCL1, CCL3, CCL4, and CCL22, attracting more CD4+ T cells and CD8+ T cells, improving immune-mediated killing, and enhancing subsequent combination anti-PD-1 therapy. These findings provide a preclinical foundation for exploring alternative treatments for patients with immunoresistant NSCLC BMs.

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.

Impact of Radiation on Exosomes in Regulating Tumor Immune Microenvironment

Purpose

Exosomes have been shown to play a role in most, if not all, steps of cancer progression. We still lack a comprehensive understanding of the bidirectional communication of exosomes between tumor cells and immune cells. This article aims to explore how exosomes can influence cancer growth and how they are affected by radiation therapy.

Methods and Materials

We searched on PubMed and Web of Science on the impact of radiation on tumor derived exosomes and immune cell derived exosomes in tumor immune microenvironment. We screened all the related articles and summarized their main discoveries and important results.

Results

This article reviewed the effects of tumor derived exosomes and immune cell-derived exosomes on TME and tumor progression after radiotherapy, suggesting the dual effects of exosomes which may refer to clinical practice. Moreover, we retrospected the clinical applications based on tumor derived exosomes, including liquid biopsy, radio-resistance and drug delivery, and discussed the challenges and prospects.

Conclusions

Exosomes are important in cancer treatment, especially with radiation therapy. Learning more about them could lead to better treatments. However, there are still challenges to overcome. The review points out the need for more research in this area.

Apigenin inhibits tumor angiogenesis by hindering microvesicle biogenesis via ARHGEF1

Extracellular vesicles are essential for intercellular communication and are involved in tumor progression. Inhibiting the direct release of extracellular vesicles seems to be an effective strategy in inhibiting tumor progression, but lacks of investigation. Here, we report a natural flavonoid compound, apigenin, could significantly inhibit the growth of hepatocellular carcinoma by preventing microvesicle secretion. Mechanistically, apigenin primarily targets the guanine nucleotide exchange factor ARHGEF1, inhibiting the activity of small G protein Cdc42, which is essential in regulating the release of microvesicles from tumor cells. In turn, this inhibits tumor angiogenesis related to VEGF90K transported on microvesicles, ultimately impeding tumor progression. Collectively, these findings highlight the therapeutic potential of apigenin and shed light on its anticancer mechanisms through inhibiting microvesicle biogenesis, providing a solid foundation for the refinement and practical application of apigenin.

Exosomes derived from miR-146a-overexpressing fibroblast-like synoviocytes in cartilage degradation and macrophage M1 polarization: a novel protective agent for osteoarthritis?

Introduction

Pathological changes in the articular cartilage (AC) and synovium are major manifestations of osteoarthritis (OA) and are strongly associated with pain and functional limitations. Exosome-derived microRNAs (miRNAs) are crucial regulatory factors in intercellular communication and can influence the progression of OA by participating in the degradation of chondrocytes and the phenotypic transformation in the polarization of synovial macrophages. However, the specific relationships and pathways of action of exosomal miRNAs in the pathological progression of OA in both cartilage and synovium remain unclear.

Methods

This study evaluates the effects of fibroblast-like synoviocyte (FLS)-derived exosomes (FLS-Exos), influenced by miR-146a, on AC degradation and synovial macrophage polarization. We investigated the targeted relationship between miR-146a and TRAF6, both in vivo and in vitro, along with the involvement of the NF-κB signaling pathway.

Results

The expression of miR-146a in the synovial exosomes of OA rats was significantly higher than in healthy rats. In vitro, the upregulation of miR-146a reduced chondrocyte apoptosis, whereas its downregulation had the opposite effect. In vivo, exosomes derived from miR-146a-overexpressing FLSs (miR-146a-FLS-Exos) reduced AC injury and chondrocyte apoptosis in OA. Furthermore, synovial proliferation was reduced, and the polarization of synovial macrophages shifted from M1 to M2. Mechanistically, the expression of TRAF6 was inhibited by targeting miR-146a, thereby modulating the Toll-like receptor 4/TRAF6/NF-κB pathway in the innate immune response.

Discussion

These findings suggest that miR-146a, mediated through FLS-Exos, may alleviate OA progression by modulating cartilage degradation and macrophage polarization, implicating the NF-κB pathway in the innate immune response. These insights highlight the therapeutic potential of miR-146a as a protective agent in OA, underscoring the importance of exosomal miRNAs in the pathogenesis and potential treatment of the disease.

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.

Extracellular Vesicles in Breast Cancer: From Intercellular Communication to Therapeutic Opportunities

Breast cancer, a multifaceted and heterogeneous disease, poses significant challenges in terms of understanding its intricate resistance mechanisms and devising effective therapeutic strategies. This review provides a comprehensive overview of the intricate landscape of extracellular vesicles (EVs) in the context of breast cancer, highlighting their diverse subtypes, biogenesis, and roles in intercellular communication within the tumour microenvironment (TME). The discussion spans various aspects, from EVs and stromal cells in breast cancer to their influence on angiogenesis, immune response, and chemoresistance. The impact of EV production in different culture systems, including two dimensional (2D), three dimensional (3D), and organoid models, is explored. Furthermore, this review delves into the therapeutic potential of EVs in breast cancer, presenting emerging strategies such as engineered EVs for gene delivery, nanoplatforms for targeted chemotherapy, and disrupting tumour derived EVs as a treatment approach. Understanding these complex interactions of EV within the breast cancer milieu is crucial for identifying resistance mechanisms and developing new therapeutic targets.

Tumor-derived microvesicles for cancer therapy

Extracellular vesicles (EVs) are vesicles with lipid bilayer structures shed from the plasma membrane of cells. Microvesicles (MVs) are a subset of EVs containing proteins, lipids, nucleic acids, and other metabolites. MVs can be produced under specific cell stimulation conditions and isolated by modern separation technology. Due to their tumor homing and large volume, tumor cell-derived microvesicles (TMVs) have attracted interest recently and become excellent delivery carriers for therapeutic vaccines, imaging agents or antitumor drugs. However, preparing sufficient and high-purity TMVs and conducting clinical transformation has become a challenge in this field. In this review, the recent research achievements in the generation, isolation, characterization, modification, and application of TMVs in cancer therapy are reviewed, and the challenges facing therapeutic applications are also highlighted.

Mutual regulation of PD-L1 immunosuppression between tumor-associated macrophages and tumor cells: a critical role for exosomes

Tumor cells primarily employ the PD-1/PD-L1 pathway to thwart the anti-tumor capabilities of T lymphocytes, inducing immunosuppression. This occurs through the direct interaction of PD-L1 with PD-1 on T lymphocyte surfaces. Recent research focusing on the tumor microenvironment has illuminated the pivotal role of immune cells, particularly tumor-associated macrophages (TAMs), in facilitating PD-L1-mediated immunosuppression. Exosomes, characterized by their ability to convey information and be engulfed by cells, significantly contribute to promoting TAM involvement in establishing PD-L1-mediated immunosuppression within the tumor microenvironment. Exosomes, characterized by their ability to convey information and be engulfed by cells, significantly contribute to promoting TAM involvement in establishing PD-L1-mediated immunosuppression within the tumor microenvironment. In addition to receiving signals from tumor-derived exosomes that promote PD-L1 expression, TAMs also exert control over PD-L1 expression in tumor cells through the release of exosomes. This paper aims to summarize the mechanisms by which exosomes participate in this process, identify crucial factors that influence these mechanisms, and explore innovative strategies for inhibiting or reversing the tumor-promoting effects of TAMs by targeting exosomes.

Tumor immune escape: extracellular vesicles roles and therapeutics application

BACKGROUND

Immune escape, a process by which tumor cells evade immune surveillance, remains a challenge for cancer therapy. Tumor cells produce extracellular vesicles (EVs) that participate in immune escape by transferring bioactive molecules between cells. EVs refer to heterogeneous vesicles that participate in intercellular communication. EVs from tumor cells usually carry tumor antigens and have been considered a source of tumor antigens to induce anti-tumor immunity. However, evidence also suggests that these EVs can accelerate immune escape by carrying heat shock proteins (HSPs), programmed death-ligand 1 (PD-L1), etc. to immune cells, suppressing function and exhausting the immune cells pool. EVs are progressively being evaluated for therapeutic implementation in cancer therapies. EVs-based immunotherapies involve inhibiting EVs generation, using natural EVs, and harnessing engineering EVs. All approaches are associated with advantages and disadvantages. The EVs heterogeneity and diverse physicochemical properties are the main challenges to their clinical applications.

SHORT CONCLUSION

Although EVs are criminal; they can be useful for overcoming immune escape. This review discusses the latest knowledge on EVs population and sheds light on the function of tumor-derived EVs in immune escape. It also describes EVs-based immunotherapies with a focus on engineered EVs, followed by challenges that hinder the clinical translation of EVs that are essential to be addressed in future investigations. Video Abstract.

EGCG inhibits the inflammation and senescence inducing properties of MDA-MB-231 triple-negative breast cancer (TNBC) cells-derived extracellular vesicles in human adipose-derived mesenchymal stem cells

BACKGROUND

Triple-negative breast cancer (TNBC) cells' secretome can induce a pro-inflammatory phenotype in human adipose-derived mesenchymal stem cells (hADMSC). This can be prevented by the green tea polyphenol epigallocatechin-3-gallate (EGCG). The impact of EGCG on the paracrine regulation that the extracellular vesicles (EVs) specifically exert within the TNBC secretome remains unknown.

METHODS

EVs were obtained from a TNBC-derived serum-starved MDA-MB-231 cell model treated or not with EGCG under normoxic or hypoxic (< 1% O2) culture conditions. RNA-Seq analysis was used to assess the EVs' genetic content. The modulation of inflammatory and senescence markers in hADMSC was evaluated by RT-qPCR using cDNA arrays and validated by immunoblotting. A protein profiler phospho-kinase array was used to explore signaling pathways.

RESULTS

While hypoxic culture conditions did not significantly alter the genetic content of MDA-MB-231-secreted EVs, the addition of EGCG significantly modified EVs genetic material at low oxygen tension. Gene expression of cancer-associated adipocyte pro-inflammatory markers CXCL8, CCL2 and IL-1β was increased in hADMSC treated with EVs. Concomitantly, EVs isolated from MDA-MB-231 treated with EGCG (EGCG-EVs) downregulated CCL2 and IL-1β, while inducing higher expression of CXCL8 and IL-6 levels. EVs activated CHK-2, c-Jun, AKT and GSK-3β signaling pathways in hADMSC, whereas EGCG-EVs specifically reduced the latter two as well as the serum starvation-induced senescence markers p21 and β-galactosidase. Finally, the mitochondrial content within the TNBC cells-derived EVs was found reduced upon EGCG treatment.

CONCLUSION

This proof of concept study demonstrates that the chemopreventive properties of diet-derived polyphenols may efficiently target the paracrine regulation that TNBC cells could exert upon their surrounding adipose tissue microenvironment.

Extracellular vesicle-cell adhesion molecules in tumours: biofunctions and clinical applications

Cell adhesion molecule (CAM) is an umbrella term for several families of molecules, including the cadherin family, integrin family, selectin family, immunoglobulin superfamily, and some currently unclassified adhesion molecules. Extracellular vesicles (EVs) are important information mediators in cell-to-cell communication. Recent evidence has confirmed that CAMs transported by EVs interact with recipient cells to influence EV distribution in vivo and regulate multiple cellular processes. This review focuses on the loading of CAMs onto EVs, the roles of CAMs in regulating EV distribution, and the known and possible mechanisms of these actions. Moreover, herein, we summarize the impacts of CAMs transported by EVs to the tumour microenvironment (TME) on the malignant behaviour of tumour cells (proliferation, metastasis, immune escape, and so on). In addition, from the standpoint of clinical applications, the significance and challenges of using of EV-CAMs in the diagnosis and therapy of tumours are discussed. Finally, considering recent advances in the understanding of EV-CAMs, we outline significant challenges in this field that require urgent attention to advance research and promote the clinical applications of EV-CAMs. Video Abstract.

Targeting cGAS/STING signaling-mediated myeloid immune cell dysfunction in TIME

Myeloid immune cells (MICs) are potent innate immune cells serving as first responders to invading pathogens and internal changes to cellular homeostasis. Cancer is a stage of altered cellular homeostasis that can originate in response to different pathogens, chemical carcinogens, and internal genetic/epigenetic changes. MICs express several pattern recognition receptors (PRRs) on their membranes, cytosol, and organelles, recognizing systemic, tissue, and organ-specific altered homeostasis. cGAS/STING signaling is a cytosolic PRR system for identifying cytosolic double-stranded DNA (dsDNA) in a sequence-independent but size-dependent manner. The longer the cytosolic dsDNA size, the stronger the cGAS/STING signaling activation with increased type 1 interferon (IFN) and NF-κB-dependent cytokines and chemokines' generation. The present article discusses tumor-supportive changes occurring in the tumor microenvironment (TME) or tumor immune microenvironment (TIME) MICs, specifically emphasizing cGAS/STING signaling-dependent alteration. The article further discusses utilizing MIC-specific cGAS/STING signaling modulation as critical tumor immunotherapy to alter TIME.

Synergistic therapeutic antitumor effect of PD-1 blockade cellular vesicles in combination with Iguratimod and Rhodium nanoparticles

Immune checkpoint blockade has emerged as a significant therapeutic development in immunotherapy during the past decade. However, only a small percentage of cancer patients respond to checkpoint blockade, suggesting that a fundamental knowledge of the underlying processes of immune checkpoint receptor signaling remains elusive and that novel therapeutic medications are needed. Here, the programmed cell death protein 1(PD-1) expressing nanovesicles were developed to enhance T cell activity. Iguratimod (IGU) and Rhodium (Rh) nanoparticles (NPs) were loaded in PD-1 nanovesicles (NVs) for synergistic therapeutic antitumor effects against lung cancer and metastasis. For the first time, this study revealed that IGU exhibits an antitumor effect by inhibiting the phosphorylation of mammalian target of rapamycin (mTOR) and Rh-NPs provided a photothermal effect by improving reactive oxygen species (ROS)-dependent apoptosis in lung cancer cells. IGU-Rh-PD-1 NVs also reduced the migration ability through the epithelial-mesenchymal transition (EMT) pathway. Furthermore, IGU-Rh-PD-1 NVs reached the targeted site and inhibited tumor growth in vivo. This strategy could boost T cell performance and simultaneously possess chemotherapeutic and photothermal therapy to serve as a new combination therapy for lung cancer and potentially other aggressive cancer.

Extracellular vesicles secreted by triple-negative breast cancer stem cells trigger premetastatic niche remodeling and metastatic growth in the lungs

Tumor secreted extracellular vesicles (EVs) are potent intercellular signaling platforms. They are responsible for the accommodation of the premetastatic niche (PMN) to support cancer cell engraftment and metastatic growth. However, complex cancer cell composition within the tumor increases also the heterogeneity among cancer secreted EVs subsets, a functional diversity that has been poorly explored. This phenomenon is particularly relevant in highly plastic and heterogenous triple-negative breast cancer (TNBC), in which a significant representation of malignant cancer stem cells (CSCs) is displayed. Herein, we selectively isolated and characterized EVs from CSC or differentiated cancer cells (DCC; EVs^CSC and EVs^DCC , respectively) from the MDA-MB-231 TNBC cell line. Our results showed that EVs^CSC and EVs^DCC contain distinct bioactive cargos and therefore elicit a differential effect on stromal cells in the TME. Specifically, EVs^DCC activated secretory cancer associated fibroblasts (CAFs), triggering IL-6/IL-8 signaling and sustaining CSC phenotype maintenance. Complementarily, EVs^CSC promoted the activation of α-SMA+ myofibroblastic CAFs subpopulations and increased the endothelial remodeling, enhancing the invasive potential of TNBC cells in vitro and in vivo. In addition, solely the EVs^CSC mediated signaling prompted the transformation of healthy lungs into receptive niches able to support metastatic growth of breast cancer cells.

Microparticle Phosphatidylserine Mediates Coagulation: Involvement in Tumor Progression and Metastasis

Tumor progression and cancer metastasis has been linked to the release of microparticles (MPs), which are shed upon cell activation or apoptosis and display parental cell antigens, phospholipids such as phosphatidylserine (PS), and nucleic acids on their external surfaces. In this review, we highlight the biogenesis of MPs as well as the pathophysiological processes of PS externalization and its involvement in coagulation activation. We review the available evidence, suggesting that coagulation factors (mainly tissue factor, thrombin, and fibrin) assist in multiple steps of tumor dissemination, including epithelial-mesenchymal transition, extracellular matrix remodeling, immune escape, and tumor angiogenesis to support the formation of the pre-metastatic niche. Platelets are not just bystander cells in circulation but are functional players in primary tumor growth and metastasis. Tumor-induced platelet aggregation protects circulating tumor cells (CTCs) from the blood flow shear forces and immune cell attack while also promoting the binding of CTCs to endothelial cells and extravasation, which activates tumor invasion and sustains metastasis. Finally, in terms of therapy, lactadherin can inhibit coagulation by competing effectively with coagulation factors for PS binding sites and may similarly delay tumor progression. Furthermore, we also investigate the therapeutic potential of coagulation factor inhibitors within the context of cancer treatment. The development of multiple therapies targeting platelet activation and platelet-tumor cell interactions may not only reduce the lethal consequences of thrombosis but also impede tumor growth and spread.

The unfolding story of dying tumor cells during cancer treatment

Generally, the demise of cancer cells in different ways enables the body to clear these harmful cells. However, cancer cells obtain unlimited replication and immortality from successful circumvention of cell death via various mechanisms. Some evidence suggests that treatment-induced dying tumor cells even promote cancer progression. Notably, therapeutic interventions to harness the immune system against tumor cells have shown complicated influences in clinics. Herein, there is an urgent need to clarify the underlying mechanisms that influence the outcome and regulation of the immune system during cancer treatment. In this review, we provide an account on the cell death modes and the relationship between dying tumor cells with tumor immune microenvironment during cancer treatment, focusing on immunotherapy, from mechanistic standpoint to emerging limitations and future directions.

Therapeutic Implications of the Drug Resistance Conferred by Extracellular Vesicles Derived from Triple-Negative Breast Cancer Cells

Anticancer drug resistance is a significant impediment in current cancer treatment. Extracellular vesicles (EVs) derived from cancer cells were recently acknowledged as a critical mechanism of drug resistance, tumor progression, and metastasis. EVs are enveloped vesicles comprising a lipid bilayer that transfers various cargo, including proteins, nucleic acids, lipids, and metabolites, from an originating cell to a recipient cell. Investigating the mechanisms whereby EVs confer drug resistance is still in the early stages. In this review, I analyze the roles of EVs derived from triple-negative breast cancer cells (TNBC-EVs) in anticancer drug resistance and discuss strategies to overcome TNBC-EV-mediated drug resistance.

Exosomes and cancer immunotherapy: A review of recent cancer research

As phospholipid extracellular vesicles (EVs) secreted by various cells, exosomes contain non-coding RNA (ncRNA), mRNA, DNA fragments, lipids, and proteins, which are essential for intercellular communication. Several types of cells can secrete exosomes that contribute to cancer initiation and progression. Cancer cells and the immune microenvironment interact and restrict each other. Tumor-derived exosomes (TDEs) have become essential players in this balance because they carry information from the original cancer cells and express complexes of MHC class I/II epitopes and costimulatory molecules. In the present study, we aimed to identify potential targets for exosome therapy by examining the specific expression and mechanism of exosomes derived from cancer cells. We introduced TDEs and explored their role in different tumor immune microenvironment (TIME), with a particular emphasis on gastrointestinal cancers, before briefly describing the therapeutic strategies of exosomes in cancer immune-related therapy.

Replication stress identifies novel molecular classification associated with treatment outcomes in pancreatic cancer

BACKGROUND

Replication stress is a prominent hallmark of tumor cells, which is crucial for maintaining genomic integrity. However, it remains poorly understood whether replication stress can serve as a surrogate biomarker to indicate prognosis and treatment response of pancreatic cancer.

METHODS

Transcriptomic and clinical data were obtained from The Cancer Genome Atlas and literature. An integrated signature of 18 replication-stress associated genes (termed as REST18) was established using the cox proportional hazards regression analysis. Tumors were sorted into REST18-low and REST18-high groups. Survival analysis, gene set enrichment analysis and composition of immune cells were compared between these tumors.

RESULTS

Patients with REST18-high tumors showed worse prognoses than those with REST18-low tumors in the TCGA database and the finding is validated in an independent cohort of pancreatic cancer. Comparison of REST18 model and other molecular classifications showed that REST18-high tumors are positively correlated to basal-like or squamous phenotypes, which have higher metastasis potential. DNA repair pathway is enriched in the REST18-high tumors. Analysis of tumor immune microenvironment found that REST18-high tumors are characterized with "immune-cold" features. Univariate and multivariate analysis show that REST18 is an independent risk factor for overall survival and predicts outcomes of chemotherapy in pancreatic cancer.

CONCLUSION

REST18 is a novel biomarker to indicate prognosis and treatment response of chemotherapy in pancreatic cancer.

Extracellular vesicles: A dive into their role in the tumor microenvironment and cancer progression

Extracellular vesicles (EVs) encompass a diverse set of membrane-derived particles released from cells and are found in numerous biological matrices and the extracellular space. Specific classes of EVs include apoptotic bodies, exosomes, and microvesicles, which vary in their size, origin, membrane protein expression, and interior cargo. EVs provide a mechanism for shuttling cargo between cells, which can influence cell physiology by transporting proteins, DNA, and RNA. EVs are an abundant component of the tumor microenvironment (TME) and are proposed to drive tumor growth and progression by communicating between fibroblasts, macrophages, and tumor cells in the TME. The cargo, source, and type of EV influences the pro- or anti-tumoral role of these molecules. Therefore, robust EV isolation and characterization techniques are required to ensure accurate elucidation of their association with disease. Here, we summarize different EV subclasses, methods for EV isolation and characterization, and a selection of current clinical trials studying EVs. We also review key studies exploring the role and impact of EVs in the TME, including how EVs mediate intercellular communication, drive cancer progression, and remodel the TME.

Extracellular vesicle-based checkpoint regulation and immune state in cancer

Tumor cells exploit several mechanisms for hijacking an immunosuppressive tumor ecosystem in order to evade immune surveillance and to progress toward metastasis. Equipment of extracellular vesicles (EVs) with checkpoints is an example of cancer control over anti-tumor responses from immune system. Programmed death-ligand 1 (PD-L1) is a checkpoint highly expressed in a tumor at progressive stage. Interactions between PD-L1 with its receptor programmed death-1 receptor (PD-1) expressed on T cells will block the effector function of CD8⁺ T cells, known as one of the most important defensive cells against cancer. Evaluation of circulatory exosomal PD-L1 can be a prognostic biomarker in tumor diagnosis and responses to the immune checkpoint inhibitor (ICI) therapy, and can be considered as a tool in clinical practice for exploiting personalized therapy. Cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) is also a checkpoint that its engagement with CD80/CD86 expressed on antigen-presenting cells (APCs), such as dendritic cells (DCs) hamper the priming phase of CD4⁺ and CD8⁺ T cells. Harvesting EVs from tumor and their modification with desired anti-checkpoint antibodies can be a promising strategy in cancer immunotherapy. The aim of this review is to discuss about EV roles in checkpoint regulation, cancer diagnosis and ICI responses, and to survey possible application of such vesicles in cancer immunotherapy.

Small extracellular vesicles: from promoting pre-metastatic niche formation to therapeutic strategies in breast cancer

Breast cancer is the most common cancer in females, and to date, the mortality rate of breast cancer metastasis cannot be ignored. The metastasis of breast cancer is a complex, staged process, and the pattern of metastatic spread is not random. The pre-metastatic niche, as an organ-specific home for metastasis, is a favourable environment for tumour cell colonization. As detection techniques improve, the role of the pre-metastatic niche in breast cancer metastasis is being uncovered. sEVs (small extracellular vesicles) can deliver cargo, which is vital for the formation of pre-metastatic niches. sEVs participate in multiple aspects of creating a distant microenvironment to promote tumour invasion, including the secretion of inflammatory molecules, immunosuppression, angiogenesis and enhancement of vascular permeability, as well as regulation of the stromal environment. Here, we discuss the multifaceted mechanisms through which breast cancer-derived sEVs contribute to pre-metastatic niches. In addition, sEVs as biomarkers and antimetastatic therapies are also discussed, particularly their use in transporting exosomal microRNAs. The study of sEVs may provide insight into immunotherapy and targeted therapies for breast cancer, and we also provide an overview of their potential role in antitumour metastasis.

Tumor-associated macrophages: Potential target of natural compounds for management of breast cancer

A large body of experimental research reveals that tumor-associated macrophages (TAMs) are the major immunosuppressor cells in the breast tumor microenvironment (TME). The infiltration of macrophages is correlated with inverse outcomes like disease-free survival and overall survival of cancer patients. They are responsible for heterogeneity, metastasis, and drug resistance. Further, their density in tumor beds is correlated with stage and therapy response. The current review is aimed at summarizing mechanisms and signaling pathways that modulate immune-suppressive phenotype and expansion of TAMs. The review presents an overview of the interdependence of tumor cells and TAMs in TME to promote metastasis, drug resistance and immune suppressive phenotype. This review also presents the potential natural compounds that modulate the immune-suppressive functions of TAMs and their signaling pathways. Finally, this review provides nanotechnology approaches for the targeted delivery of natural products. This review shed light on BC management including clinical studies on the prognostic relevance of TAMs and natural compounds that sensitizes BC.

Microparticles: biogenesis, characteristics and intervention therapy for cancers in preclinical and clinical research

Extracellular vesicles (EVs), spherical biological vesicles, mainly contain nucleic acids, proteins, lipids and metabolites for biological information transfer between cells. Microparticles (MPs), a subtype of EVs, directly emerge from plasma membranes, and have gained interest in recent years. Specific cell stimulation conditions, such as ultraviolet and X-rays irradiation, can induce the release of MPs, which are endowed with unique antitumor functionalities, either for therapeutic vaccines or as direct antitumor agents. Moreover, the size of MPs (100–1000 nm) and their spherical structures surrounded by a lipid bilayer membrane allow MPs to function as delivery vectors for bioactive antitumor compounds, with favorable phamacokinetic behavior, immunostimulatory activity and biological function, without inherent carrier-specific toxic side effects. In this review, the mechanisms underlying MP biogenesis, factors that influence MP production, properties of MP membranes, size, composition and isolation methods of MPs are discussed. Additionally, the applications and mechanisms of action of MPs, as well as the main hurdles for their applications in cancer management, are introduced.

Extracellular vesicle PD-L1 in reshaping tumor immune microenvironment: biological function and potential therapy strategies

Programmed cell death 1 ligand 1 (PD-L1) is the ligand for programmed death protein-1 (PD-1), is associated with immunosuppression. Signaling via PD-1/PD-L1 will transmits negative regulatory signals to T cells, inducing T-cell inhibition, reducing CD8⁺ T-cell proliferation, or promoting T-cell apoptosis, which effectively reduces the immune response and leads to large-scale tumor growth. Accordingly, many antibody preparations targeting PD-1 or PD-L1 have been designed to block the binding of these two proteins and restore T-cell proliferation and cytotoxicity of T cells. However, these drugs are ineffective in clinical practice. Recently, numerous of studies have shown that, in addition to the surface of tumor cells, PD-L1 is also found on the surface of extracellular vesicles secreted by these cells. Extracellular vesicle PD-L1 can also interact with PD-1 on the surface of T cells, leading to immunosuppression, and has been proposed as a potential mechanism underlying PD-1/PD-L1-targeted drug resistance. Therefore, it is important to explore the production, regulation and tumor immunosuppression of PD-L1 on the surface of tumor cells and extracellular vesicles, as well as the potential clinical application of extracellular vesicle PD-L1 as tumor biomarkers and therapeutic targets.

Video Abstract

STAT6 contributes to renal fibrosis by modulating PPARα-mediated tubular fatty acid oxidation

Lipid metabolism, especially fatty acid oxidation (FAO) dysfunction, is a major driver of renal fibrosis; however, the detailed regulatory mechanisms involved remain unclear. In this study, we showed that there existed an association between the signal transducer and activator of transcription 6 (STAT6) and tubular lipid metabolism in fibrotic kidneys. Specifically, STAT6 was activated along with the accumulation of lipids via the downregulation of FAO-related genes when mice were subjected to unilateral ureteral obstruction (UUO) or high-fat diet challenge. Tubular-specific depletion, or pharmacologic inhibitor of Stat6 in mice, and Stat6 knockdown in cultured tubular cells attenuated lipid accumulation and renal fibrosis by enhancing FAO. Mechanistically, STAT6 transcriptionally inhibited the expression of PPARα and its FAO-related target genes through a sis-inducible element located in the promoter region of the protein. In conclusion, our study demonstrates the mechanistic details of STAT6-mediated FAO dysregulation in the progression of renal fibrosis and provides a preclinical rationale for efforts to improve the management of renal fibrosis brought about by FAO dysregulation.

The potential value of amlexanox in the treatment of cancer: Molecular targets and therapeutic perspectives

Amlexanox (AMX) is an azoxanthone drug used for decades for the treatment of mouth aphthous ulcers and now considered for the treatment of diabetes and obesity. The drug is usually viewed as a dual inhibitor of the non-canonical IκB kinases IKK-ɛ (inhibitor-kappaB kinase epsilon) and TBK1 (TANK-binding kinase 1). But a detailed target profile analysis indicated that AMX binds directly to twelve protein targets, including different enzymes (IKK-ɛ, TBK1, GRK1, GRK5, PDE4B, 5- and 12-lipoxygenases) and non-enzyme proteins (FGF-1, HSP90, S100A4, S100A12, S100A13). AMX has been demonstrated to have marked anticancer effects in multiple models of xenografted tumors in mice, including breast, colon, lung and gastric cancers and in onco-hematological models. The anticancer potency is generally modest but largely enhanced upon combination with cytotoxic (temozolide, docetaxel), targeted (selumetinib) or biotherapeutic agents (anti-PD-1 and anti-CTLA4 antibodies). The multiple targets participate in the anticancer effects, chiefly IKK-ɛ/TBK1 but also S100A proteins and PDE4B. The review presents the molecular basis of the antitumor effects of AMX. The capacity of the drug to block nonsense-mediated mRNA decay (NMD) is also discussed, as well as AMX-induced reduction of cancer-related pain. Altogether, the analysis provides a survey of the anticancer action of AMX, with the implicated protein targets. The use of this well-tolerated drug to treat cancer should be further considered and the design of newer analogues encouraged.