Impact of Chemotherapy on Extracellular Vesicles: Understanding the Chemo-EVs

Extracellular vesicle-associated DNA: ten years since its discovery in human blood

Extracellular vesicles (EVs) have emerged as key players in intercellular communication, facilitating the transfer of crucial cargo between cells. Liquid biopsy, particularly through the isolation of EVs, has unveiled a rich source of potential biomarkers for health and disease, encompassing proteins and nucleic acids. A milestone in this exploration occurred a decade ago with the identification of extracellular vesicle-associated DNA (EV-DNA) in the bloodstream of a patient diagnosed with pancreatic cancer. Subsequent years have witnessed substantial advancements, deepening our insights into the molecular intricacies of EV-DNA emission, detection, and analysis. Understanding the complexities surrounding the release of EV-DNA and addressing the challenges inherent in EV-DNA research are pivotal steps toward enhancing liquid biopsy-based strategies. These strategies, crucial for the detection and monitoring of various pathological conditions, particularly cancer, rely on a comprehensive understanding of why and how EV-DNA is released. In our review, we aim to provide a thorough summary of a decade's worth of research on EV-DNA. We will delve into diverse mechanisms of EV-DNA emission, its potential as a biomarker, its functional capabilities, discordant findings in the field, and the hurdles hindering its clinical application. Looking ahead to the next decade, we envision that advancements in EV isolation and detection techniques, coupled with improved standardization and data sharing, will catalyze the development of novel strategies exploiting EV-DNA as both a source of biomarkers and therapeutic targets.

Strategies for Small Extracellular Vesicle-Based Cancer Immunotherapy

Extracellular vesicles (EVs) are lipid bilayer-enclosed vesicles released by cells. EVs encapsulate proteins and nucleic acids of their parental cell and efficiently deliver the cargo to recipient cells. These vesicles act as mediators of intercellular communication and thus play a crucial role in various physiological and pathological processes. Moreover, EVs hold promise for clinical use. They have been explored as drug delivery vehicles, therapeutic agents, and targets for disease diagnosis. In the landscape of cancer research, while strides have been made in EV-focused cancer physiopathology, liquid biopsy, and drug delivery, the exploration of EVs as immunotherapeutic agents may not have seen substantial progress to date. Despite promising findings reported in cell and animal studies, the clinical translation of EV-based cancer immunotherapeutics encounters challenges. Here, we review the existing strategies used in EV-based cancer immunotherapy, aiming to propel the development of this emerging yet crucial field.

Chemo-small extracellular vesicles released in cisplatin-resistance ovarian cancer cells are regulated by the lysosomal function

Chemoresistance is a common problem in ovarian cancer (OvCa) treatment, where resistant cells, in response to chemotherapy, secrete small extracellular vesicles (sEVs), known as chemo-sEVs, that transfer resistance to recipient cells. sEVs are formed as intraluminal vesicles (ILVs) within multivesicular endosomes (MVEs), whose trafficking is regulated by Ras-associated binding (RAB) GTPases that mediate sEVs secretion or lysosomal degradation. A decrease in lysosomal function can promote sEVs secretion, but the relationship between MVEs trafficking pathways and sEVs secretion in OvCa chemoresistance is unclear. Here, we show that A2780cis cisplatin (CCDP) resistant OvCa cells had an increased number of MVEs and ILVs structures, higher levels of Endosomal Sorting Complex Required for Transport (ESCRTs) machinery components, and RAB27A compared to A2780 CDDP-sensitive OvCa cells. CDDP promoted the secretion of chemo-sEVs in A2780cis cells, enriched in DNA damage response proteins. A2780cis cells exhibited poor lysosomal function with reduced levels of RAB7, essential in MVEs-Lysosomal trafficking. The silencing of RAB27A in A2780cis cells prevents the Chemo-EVs secretion, reduces its chemoresistance and restores lysosomal function and levels of RAB7, switching them into an A2780-like cellular phenotype. Enhancing lysosomal function with rapamycin reduced chemo-sEVs secretion. Our results suggest that adjusting the balance between secretory MVEs and lysosomal MVEs trafficking could be a promising strategy for overcoming CDDP chemoresistance in OvCa.

Cisplatin-induced PANDAR-Chemo-EVs contribute to a more aggressive and chemoresistant ovarian cancer phenotype through the SRSF9-SIRT4/SIRT6 axis

OBJECTIVE

We previously elucidated that long non-coding RNA Promoter of CDKN1A Antisense DNA damage Activated RNA (PANDAR) as a p53-dependent oncogene to promote cisplatin resistance in ovarian cancer (OC). Intriguingly, high level of p53-independent PANDAR was found in cisplatin-resistant patients with p53 mutation. Here, our study probed the new roles and the underlying mechanisms of PANDAR in p53-mutant OC cisplatin-resistance.

METHODS

A2780 and A2780-DDP cells were served as OC cisplatin-sensitive and cisplatin-resistant cells. HO-8910PM cells were subjected to construct chemotherapy-induced extracellular vesicles (Chemo-EVs). Transmission electron microscopy (TEM) and nanoparticle tracking analysis were employed to evaluate Chemo-EVs. Cell viability was assessed using cell counting kit-8 and colony formation assays. Cell apoptosis was assessed using Annexin V and propidium iodide staining. The relationships between PANDAR, serine and arginine-rich pre-mRNA splicing factor 9 (SRSF9) were verified by RNA immunoprecipitation and fluorescence in situ hybridization. Tumor xenograft experiment was employed to evaluate the effects of PANDAR-Chemo-EVs on OC cisplatin-resistance in vivo. Immunofluorescent staining and immunohistochemistry were performed in tumor tissue.

RESULTS

PANDAR level increased in OC patients with p53-mutation. PANDAR efflux enacted via exosomes under cisplatin conditions. Additionally, exosomes from OC cell lines carried PANDAR, which significantly increased cell survival and chemoresistance in vitro and tumor progression and metastasis in vivo. During cisplatin-induced stress, SRSF9 was recruited to nuclear bodies by increased PANDAR and muted apoptosis in response to cisplatin. Besides, SRSF9 significantly increased the ratio of SIRT4/SIRT6 mRNA in OC.

CONCLUSION

Cisplatin-induced exosomes transfer PANDAR and lead to a rapid adaptation of OC cell survival through accumulating SRSF9 following cisplatin stress exposure.

Methods behind oncolytic virus-based DC vaccines in cancer: Toward a multiphase combined treatment strategy for Glioblastoma (GBM) patients

Glioblastoma (GBM) remains an orphan cancer disease with poor outcome. Novel treatment strategies are needed. Immunotherapy has several modes of action. The addition of active specific immunotherapy with dendritic cell vaccines resulted in improved overall survival of patients. Integration of DC vaccination within the first-line combined treatment became a challenge, and immunogenic cell death immunotherapy during chemotherapy was introduced. We used a retrospective analysis using real world data to evaluate the complex combined treatment, which included individualized multimodal immunotherapy during and after standard of care, and which required adaptations during treatment, and found a further improvement of overall survival. We also discuss the use of real world data as evidence. Novel strategies to move the field of individualized multimodal immunotherapy forward for GBM patients are reviewed.

Monitoring of single extracellular vesicle heterogeneity in cancer progression and therapy

Cancer cells actively release lipid bilayer extracellular vesicles (EVs) that affect their microenvironment, favoring their progression and response to extracellular stress. These EVs contain dynamically regulating molecular cargos (proteins and nucleic acids) selected from their parental cells, representing the active biological functionality for cancer progression. These EVs are heterogeneous according to their size and molecular composition and are usually defined based on their biogenetic mechanisms, such as exosomes and ectosomes. Recent single EV detection technologies, such as nano-flow cytometry, have revealed the dynamically regulated molecular diversity within bulk EVs, indicating complex EV heterogeneity beyond classical biogenetic-based EV subtypes. EVs can be changed by internal oncogenic transformation or external stress such as chemotherapy. Among the altered combinations of EV subtypes, only a specific set of EVs represents functional molecular cargo, enabling cancer progression and immune modulation in the tumor microenvironment through their altered targeting efficiency and specificity. This review covers the heterogeneity of EVs discovered by emerging single EV analysis technologies, which reveal the complex distribution of EVs affected by oncogenic transformation and chemotherapy. Encouragingly, these unique molecular signatures in individual EVs indicate the status of their parental cancer cells. Thus, precise molecular profiling of circulating single EVs would open new areas for in-depth monitoring of the cancer microenvironment and shed new light on non-invasive diagnostic approaches using liquid biopsy.

Tumor Cells Transmit Drug Resistance via Cisplatin-Induced Extracellular Vesicles

Cisplatin is a first-line clinical agent used for treating solid tumors. Cisplatin damages the DNA of tumor cells and induces the production of high levels of reactive oxygen species to achieve tumor killing. Tumor cells have evolved several ways to tolerate this damage. Extracellular vesicles (EVs) are an important mode of information transfer in tumor cells. EVs can be substantially activated under cisplatin treatment and mediate different responses of tumor cells under cisplatin treatment depending on their different cargoes. However, the mechanism of action of tumor-cell-derived EVs under cisplatin treatment and their potential cargoes are still unclear. This review considers recent advances in cisplatin-induced release of EVs from tumor cells, with the expectation of providing a new understanding of the mechanisms of cisplatin treatment and drug resistance, as well as strategies for the combined use of cisplatin and other drugs.

Piperlongumine inhibits proliferation and oncogenic MYCN expression in chemoresistant metastatic retinoblastoma cells directly and through extracellular vesicles

Ocular retinoblastoma malignancies, which develop into metastatic phenotypes, result in poor prognosis and survival for infant and child patients. To improve the prognosis of metastatic retinoblastoma, it is important to identify novel compounds with less toxic side effects and higher therapeutic efficacy compared to existing chemotherapeutics. Piperlongumine (PL), a neuroprotective, plant-derived compound has been explored for its anticancer activities both in vitro and in vivo. Here, we analyze the potential efficacy of PL for metastatic retinoblastoma cell treatment. Our data reveal that PL treatment significantly inhibits cell proliferation in metastatic retinoblastoma Y79 cells compared to the commonly used retinoblastoma chemotherapeutic drugs carboplatin, etoposide, and vincristine. PL treatment also significantly increases cell death compared to treatment with other chemotherapeutic drugs. PL-induced cell-death signaling was associated with significantly higher caspase 3/7 activities and greater loss of mitochondrial membrane potential. PL was also internalized into Y79 cells with an estimated concentration of 0.310pM and expression analysis revealed reduced MYCN oncogene levels. We next examined extracellular vesicles derived from PL-treated Y79 cells. Extracellular vesicles in other cancers are pro-oncogenic, mediating systemic toxicities via the encapsulation of chemotherapeutic drugs. Within metastatic Y79 EV samples, an estimated PL concentration of 0.026pM was detected. PL treatment significantly downregulated Y79 EV cargo of the oncogene MYCN transcript. Interestingly, non-PL-treated Y79 cells incubated with EVs from PL-treated cells exhibited significantly reduced cell growth. These findings indicate that in metastatic Y79 cells, PL exhibits potent anti-proliferation effects and oncogene downregulation. Importantly, PL is also incorporated into extracellular vesicles released from treated metastatic cells with measurable anti-cancer effects on target cells at a distance from the site of primary treatment. The use of PL in the treatment of metastatic retinoblastoma may reduce primary tumor proliferation and inhibit metastatic cancer activity systemically via extracellular vesicle circulation.

Treatment dependent impact of plasma-derived exosomes from head and neck cancer patients on the epithelial-to-mesenchymal transition

Background

Epithelial to mesenchymal transition (EMT) is a key process in carcinogenesis of head and neck squamous cell carcinoma (HNSCC), contributing to tumor invasiveness, distant metastasis, and recurrence. Exosomes are known mediators and regulators of EMT. Here, we analyze the impact of exosomes that were primed by conventional therapy on EMT modulation.

Methods

Plasmas of n = 22 HNSCC patients were collected before and after standard of care surgery and adjuvant or primary (chemo)radiotherapy. Exosomes were isolated by size exclusion chromatography. Upon co-incubation of exosomes with HNSCC cells, the cellular EMT profile was analyzed by flow cytometry and RT-qPCR. Wound healing assays were performed to evaluate migratory potential of exosome-treated cells.

Results

Reduction of total exosome protein after therapy and in vitro exosome induced EMT profiles were dependent on the type of treatment. Exosomal TFG-β and miRNA cargo were partly responsible for observed exosome induced EMT changes. Exosomes from recurrent patients induced higher tumor cell migration after therapy than exosomes from disease-free patients.

Conclusions

HNSCC patients' exosomes from timepoints before and after therapy were able to confer therapy induced EMT modulation in vitro and have the potential to monitor the EMT process. Exosome induced changes in migratory potential emerged as discriminants of therapy outcome.

Role of exosomes in tumour growth, chemoresistance and immunity: state-of-the-art

Cancer is one of the most lethal diseases, and limited available treatment options contribute to its high mortality rate. Exosomes are considered membrane-bound nanovesicles that include different molecules such as lipids, proteins, and nucleic acids. Virtually most cells could release exosomes via exocytosis in physiological and pathological conditions. Tumour-derived exosomes (TDEs) play essential roles in tumorigenesis, proliferation, progression, metastasis, immune escape, and chemoresistance by transferring functional biological cargos, triggering different autocrine, and paracrine signalling cascades. Due to their antigen-presenting properties, exosomes are widely used as biomarkers and drug carriers and have a prominent role in cancer immunotherapy. They offer various advantages in carrier systems (e.g. in chemotherapy, siRNA, and miRNA), delivery of diagnostic agents owing to their stability, loading of hydrophobic and hydrophilic agents, and drug targeting. Novel exosomes-based carriers can be generated as intelligent systems using various sources and crosslinking chemistry extracellular vesicles (EVs). Exosomes studded with targeting ligands, including peptides, can impart in targeted delivery of cargos to tumour cells. In this review, we comprehensively summarised the important role of tumour-derived exosomes in dictating cancer pathogenesis and resistance to therapy. We have therefore, investigated in further detail the pivotal role of tumour-derived exosomes in targeting various cancer cells and their applications, and prospects in cancer therapy and diagnosis. Additionally, we have implicated the potential utility and significance of tumour exosomes-based nanoparticles as an efficient and novel therapeutic carrier and their applications in treating advanced cancers.

Current State of Immunotherapy and Mechanisms of Immune Evasion in Ewing Sarcoma and Osteosarcoma

We argue here that in many ways, Ewing sarcoma (EwS) is a unique tumor entity and yet, it shares many commonalities with other immunologically cold solid malignancies. From the historical perspective, EwS, osteosarcoma (OS) and other bone and soft-tissue sarcomas were the first types of tumors treated with the immunotherapy approach: more than 100 years ago American surgeon William B. Coley injected his patients with a mixture of heat-inactivated bacteria, achieving survival rates apparently higher than with surgery alone. In contrast to OS which exhibits recurrent somatic copy-number alterations, EwS possesses one of the lowest mutation rates among cancers, being driven by a single oncogenic fusion protein, most frequently EWS-FLI1. In spite these differences, both EwS and OS are allied with immune tolerance and low immunogenicity. We discuss here the potential mechanisms of immune escape in these tumors, including low representation of tumor-specific antigens, low expression levels of MHC-I antigen-presenting molecules, accumulation of immunosuppressive M2 macrophages and myeloid proinflammatory cells, and release of extracellular vesicles (EVs) which are capable of reprogramming host cells in the tumor microenvironment and systemic circulation. We also discuss the vulnerabilities of EwS and OS and potential novel strategies for their targeting.

Current perspectives on clinical use of exosomes as novel biomarkers for cancer diagnosis

Exosomes are a heterogeneous subset of extracellular vesicles (EVs) that biogenesis from endosomes. Besides, exosomes contain a variety of molecular cargoes including proteins, lipids and nucleic acids, which play a key role in the mechanism of exosome formation. Meanwhile, exosomes are involved with physiological and pathological conditions. The molecular profile of exosomes reflects the type and pathophysiological status of the originating cells so could potentially be exploited for diagnostic of cancer. This review aims to describe important molecular cargoes involved in exosome biogenesis. In addition, we highlight exogenous factors, especially autophagy, hypoxia and pharmacology, that regulate the release of exosomes and their corresponding cargoes. Particularly, we also emphasize exosome molecular cargoes as potential biomarkers in liquid biopsy for diagnosis of cancer.

cGAS/cGAMP/STING signal propagation in the tumor microenvironment: key role for myeloid cells in antitumor immunity

Cyclic GMP-AMP synthase (cGAS), second messenger 2'3'-cyclic GMP-AMP (cGAMP) and stimulator of interferon genes (STING) are fundamental for sensing cytoplasmic double stranded DNA. Radiotherapy treatment induces large amounts of nuclear and mitochondrial DNA damage and results in the presence of DNA fragments in the cytoplasm, activating the cGAS/STING pathway. Triggering of the cGAS/STING pathway in the tumor microenvironment (TME) results in the production of type I interferons (IFNs). Type I IFNs are crucial for an effective antitumor defense, with myeloid cells as key players. Many questions remain on how these myeloid cells are activated and in which cells (tumor versus myeloid) in the TME the signaling pathway is initiated. The significance of cGAS/STING signaling in the onco-immunology field is being recognized, emphasized by the frequent occurrence of mutations in or silencing of genes in this pathway. We here review several mechanisms of cGAS/STING signal propagation in the TME, focusing on tumor cells and myeloid cells. Cell-cell contact-dependent interactions facilitate the transfer of tumor-derived DNA and cGAMP. Alternatively, transport routes via the extracellular space such as extracellular vesicles, and channel-mediated cGAMP transfer to and from the extracellular space contribute to propagation of cGAS/STING signal mediators DNA and cGAMP. Finally, we discuss regulation of extracellular cGAMP. Altogether, we provide a comprehensive overview of cGAS/cGAMP/STING signal propagation from tumor to myeloid cells in the TME, revealing novel targets for combinatorial treatment approaches with conventional anticancer therapies like radiotherapy.

Tumor-derived extracellular vesicles: Potential tool for cancer diagnosis, prognosis, and therapy

Various types of cancer pose a notable threat to human health globally. To date, many researchers have undertaken the search for anticancer therapies. However, many anticancer therapeutic approaches accompany many undesirable hazards. In this respect, extracellular vesicles as a whole gained excessive attention from the research community owing to their remarkable potential for delivery of anticancer agents since they are involved in distal intercellular communication via biological cargoes. With the discovery of the fact that tumor cells discharge huge quantities of EVs, new insights have been developed in cancer diagnosis and treatment. Tumor-derived extracellular vesicles (TD-EVs) can be distinguished from the normal cell-derived EVs due to the presence of specific labels on their surface. TD-EVs carry specific oncogenic proteins and the nucleic acids on their surface membrane that participate in tumor progression. Moreover, the proportion of these nucleic acids and the protein greatly varies among malignant and healthy cell-derived EVs. The diagnostic potential of TD-EVs can be implied for the more precise and early-stage detection of cancer that was impossible in the past. This review examines the recent progress in prognostic, diagnostic, and therapeutic potential of the EVs derived from the tumor cells.

Inhibiting collagen I production and tumor cell colonization in the lung via miR-29a-3p loading of exosome-/liposome-based nanovesicles

The lung is one of the most common sites for cancer metastasis. Collagens in the lung provide a permissive microenvironment that supports the colonization and outgrowth of disseminated tumor cells. Therefore, down-regulating the production of collagens may contribute to the inhibition of lung metastasis. It has been suggested that miR-29 exhibits effective anti-fibrotic activity by negatively regulating the expression of collagens. Indeed, our clinical lung tumor data shows that miR-29a-3p expression negatively correlates with collagen I expression in lung tumors and positively correlates with patients’ outcomes. However, suitable carriers need to be selected to deliver this therapeutic miRNA to the lungs. In this study, we found that the chemotherapy drug cisplatin facilitated miR-29a-3p accumulation in the exosomes of lung tumor cells, and this type of exosomes exhibited a specific lung-targeting effect and promising collagen down-regulation. To scale up the preparation and simplify the delivery system, we designed a lung-targeting liposomal nanovesicle (by adjusting the molar ratio of DOTAP/cholesterol–miRNAs to 4:1) to carry miR-29a-3p and mimic the exosomes. This liposomal nanovesicle delivery system significantly down-regulated collagen I secretion by lung fibroblasts in vivo, thus alleviating the establishment of a pro-metastatic environment for circulating lung tumor cells.

Comparative mRNA/micro-RNA co-expression network drives melanomagenesis by promoting epithelial-mesenchymal transition and vasculogenic mimicry signaling

This study aimed to identify a novel disease-associated differentially co-expressed mRNA-microRNA (miRNA) that is associated with vasculogenic mimicry (VM) and epithelial-to-mesenchymal transition (EMT) network at different stages of melanoma. By applying weighted gene co-expression network analysis, we constructed a VM+EMT biological network with the available microarray dataset downloaded from a public database. Quantitative real-time PCR, immunohistochemical staining, and CD31-periodic acid solution dual staining were performed to confirm the expression of genes associated with EMT and VM formation in subjects with malignant melanoma (n = 18) and primary melanoma (n = 13) and in healthy subjects (n = 10). Our findings suggested that phosphatidylserine-specific phospholipase A1-alpha (PLA1A) and dermokine (DMKN) genes function as oncogenes that trigger VM and EMT processes during melanomagenesis on interaction with miR-370, miR-563, and miR-770-5p. PLA1A and DMKN genes can be considered potential VM+EMT network-based diagnostic biomarkers for distinguishing between melanoma patients. We postulate that a network with altered PLA1A/miR-563 and DMNK/miR-770-5p/miR-370 may contribute to melanomagenesis by triggering the EMT signaling pathway and VM formation. This study provides a potentially valuable approach for the early diagnosis and prognosis of melanoma progression.

Treatment Failure in Acute Myeloid Leukemia: Focus on the Role of Extracellular Vesicles

Acute myeloblastic leukemia (AML) is one of the most common types of blood malignancies that results in an AML-associated high mortality rate each year. Several causes have been reported as prognostic factors for AML in children and adults, the most important of which are cytogenetic abnormalities and environmental risk factors. Following the discovery of numerous drugs for AML treatment, leukemic cells sought a way to escape from the cytotoxic effects of chemotherapy drugs, leading to treatment failure. Nowadays, comprehensive studies have looked at the role of extracellular vesicles (EVs) secreted by AML blasts and how the microenvironment of the tumor changes in favor of cancer progression and survival to discover the mechanisms of treatment failure to choose the well-advised treatment. Reports show that malignant cells secrete EVs that transmit messages to adjacent cells and the tumor's microenvironment. By secreting EVs, containing immune-inhibiting cytokines, AML cells inactivate the immune system against malignant cells, thus ensuring their survival. Also, increased secretion of EVs in various malignancies indicates an unfavorable prognostic factor and the possibility of drug resistance. In this study, we briefly reviewed the challenges of treating AML with a glance at the EVs' role in this process. It is hoped that with a deeper understanding of EVs, new therapies will be developed to eliminate the relapse of leukemic cells.

Extracellular Vesicles and DAMPs in Cancer: A Mini-Review

Certain cancer therapy has been shown to induce immunogenic cell death in cancer cells and may promote tumor progression instead. The external stress or stimuli may induce cell death and contribute toward the secretion of pro inflammatory molecules. The release of damage-associated molecular patterns (DAMPs) upon induction of therapy or cell death has been shown to induce an inflammatory response. Nevertheless, the mechanism as to how the DAMPs are released and engage in such activity needs further in-depth investigation. Interestingly, some studies have shown that DAMPs can be released through extracellular vesicles (EVs) and can bind to receptors such as toll-like receptors (TCRs). Ample pre-clinical studies have shown that cancer-derived EVs are able to modulate immune responses within the tumor microenvironment. However, the information on the presence of such DAMPs within EVs is still elusive. Therefore, this mini-review attempts to summarize and appraise studies that have shown the presence of DAMPs within cancer-EVs and how it affects the downstream cellular process.

Diagnostic Role of Extracellular Vesicles in Cancer: A Comprehensive Systematic Review and Meta-Analysis

Background: Cancer-derived extracellular vesicles (EVs) are regarded to have significant function in most steps during cancer progression. This meta-analysis aims to investigate the accuracy of EVs as a biomarker in cancer diagnosis.

Methods: The diagnostic efficacy of EVs for different cancers was assessed using pooled sensitivity and specificity, diagnostic odds ratio (DOR), and overall area under the curve (AUC) of the summary receiver operating characteristic (SROC). The positive likelihood ratio (PLR) and negative likelihood ratio (NLR) were verified to estimate the diagnostic efficacy of EV at a clinical level.

Results: In all, 6,183 cancer patients and 2,437 healthy controls from 75 eligible studies reported in 42 publications were included in the study. The overall pooled sensitivity, specificity, PLR, NLR, and DOR were 0.62 (95% CI: 0.60–0.63), 0.76 (95% CI: 0.75–0.78), 3.07 (95% CI: 2.52–3.75), 0.34 (95% CI: 0.28–0.41), and 10.98 (95% CI: 7.53–16.00), respectively. Similarly, the AUC of the SROC was 0.88, indicating a high conservation of EVs as an early diagnostic marker. Furthermore, subgroup analysis suggested that the use of small EVs as a biomarker was more accurate in serum-based samples of nervous system cancer (p < 0.001). As a result, ultracentrifugation and quantification and size determination methods, such as Western blotting and ELISA were the most reliable identification methods for EV detection. We also indicated that increased secretion of EVs made them a capable biomarker for diagnosing cancer in elderly European individuals.

Conclusions: Our study provides evidence that EVs are a promising non-invasive biomarker for cancer diagnosis. Well-designed cohort studies should be conducted to warrant the clinical diagnostic value of EVs.

Elevated Level of Nerve Growth Factor (NGF) in Serum-Derived Exosomes Predicts Poor Survival in Patients with Breast Cancer Undergoing Neoadjuvant Chemotherapy

Simple Summary

Exosomes and cytokines play crucial roles in the process of tumor progression. Recent studies have reported that cytokines can be packaged into exosomes, leading to drug resistance. The aim of this study is to evaluate the potential value of cytokines in both serum and exosomes as prognostic biomarkers of long-term outcomes in patients with breast cancer treated with neoadjuvant chemotherapy. We observed significant differences in expression patterns between serum cytokines and exosomal cytokines. Elevated levels of serum IP-10, serum MMP-1, and exosomal NGF were associated with poor overall survival. In multivariate analysis, exosomal NGF was an independent prognostic factor for overall survival. These findings suggest that exosomal NGF is useful for identifying patients with poor survival outcomes.

Abstract

Neoadjuvant chemotherapy (NAC) is a standard treatment strategy for patients with locally advanced breast cancer (LABC). However, there are no established predictors of chemosensitivity and survival in LABC patients who undergo NAC. Many studies have demonstrated that exosomes and cytokines are important players in intercellular communication between tumors and their environments, and are involved in chemotherapy resistance. Recently, it was reported that cytokines can be packaged into exosomes, but whether exosomal cytokines serve as biomarkers in breast cancer patients is still unclear. In this study, we examined the roles of cytokines in both serum and exosomes as prognostic biomarkers for long-term outcomes in patients with breast cancer who undergo NAC. We isolated exosomes from the blood of 129 patients with early breast cancer who were receiving neoadjuvant chemotherapy between 2008 and 2011 at Samsung Medical Center. The levels of cytokines and growth factors in serum and exosomes were measured with ProcartaPlex immune-related panels. We investigated correlations between clinic-pathologic variables and patient survival, and Cox proportional hazards regression analysis was performed for prognostic evaluation. We detected significant differences in expression patterns between serum cytokines and exosomal cytokines. In both serum and exosomes, many cytokines were positively correlated with age. In univariate analysis, patients with high serum IP-10, serum MMP-1, and exosomal NGF had shorter overall survival. Exosomal NGF showed significantly poorer overall survival in multivariate analysis. These findings suggest that exosomal NGF is useful for identifying patients with poor survival outcomes.

Technological advances towards extracellular vesicles mass production

Extracellular vesicles (EVs) are becoming essential actors in bio-therapeutics, as much for their regenerative or immunomodulatory properties as for their potential as cargo delivery vehicles. To enable the democratization of these EV-based therapies, many challenges remain such as large-scale production which is necessary to reduce costs of treatment. Herein, we review some advanced works on high-yield EV manufacturing. One approach consists in developing large-scale cell culture platforms, while others focus on cell stimulation to increase particle yield per cell. This can be done by moderate physico-chemical stresses or by disrupting cell membrane towards autoassembled vesicle-like particles. We critically compare these different techniques, keeping in mind that the field still lacks shared characterization standards, underline the importance of therapeutic potency assessment and discuss mass production strategies that have been identified in current clinical trials.

Extracellular vesicles in urological malignancies

Extracellular vesicles (EVs) are small lipid bound structures released from cells containing bioactive cargoes. Both the type of cargo and amount loaded varies compared to that of the parent cell. The characterisation of EVs in cancers of the male urogenital tract has identified several cargoes with promising diagnostic and disease monitoring potential. EVs released by cancers of the male urogenital tract promote cell-to-cell communication, migration, cancer progression and manipulate the immune system promoting metastasis by evading the immune response. Their use as diagnostic biomarkers represents a new area of screening and disease detection, potentially reducing the need for invasive biopsies. Many validated EV cargoes have been found to have superior sensitivity and specificity than current diagnostic tools currently in use. The use of EVs to improve disease monitoring and develop novel therapeutics will enable clinicians to individualise patient management in the exciting era of personalised medicine.

Retinoblastoma Is Characterized by a Cold, CD8+ Cell Poor, PD-L1- Microenvironment, Which Turns Into Hot, CD8+ Cell Rich, PD-L1+ After Chemotherapy

Purpose

To investigate the impact of chemotherapy (CHT) on human retinoblastoma (RB) tumor microenvironment (TME).

Cases and Methods

Ninety-four RBs were studied, including 44 primary RBs treated by upfront surgery (Group 1) and 50 primary RBs enucleated after CHT (CHT), either intra-arterial (IAC; Group 2, 33 cases) or systemic (S-CHT; Group 3, 17 cases). Conventional and multiplexed immunohistochemistry were performed to make quantitative comparisons among the three groups, for the following parameters: tumor-infiltrating inflammatory cells (TI-ICs); programmed cell death protein 1 (PD-1) positive TI-ICs; Ki67 proliferation index; gliosis; PD-1 ligand (PD-L1) protein expression; vessel number. We also correlated these TME factors with the presence of histological high-risk factors (HHRF+) and RB anaplasia grade (AG).

Results

After CHT, a decrease in both RB burden and Ki67 positivity was observed. In parallel, most subsets of TI-ICs, PD-1+ TI-ICs, gliosis, and PD-L1 protein expression significantly increased (P < 0.001, P = 0.02, P < 0.001, respectively). Vessel number did not significantly vary. Age, HHRFs+ and AG were significantly different between primary and chemoreduced RBs (P < 0.001, P = 0.006, P = 0.001, respectively) and were correlated with most TME factors.

Conclusions

CHT modulates host antitumor immunity by reorienting the RB TME from anergic into an active, CD8+, PD-L1+ hot state. Furthermore, some clinicopathological characteristics of RB correlate with several factors of TME. Our study adds data in favor of the possibility of a new therapeutic scenario in human RB.

The impact of neoadjuvant concurrent chemoradiation on exosomal markers (CD63 and CD9) expression and their prognostic significance in patients with rectal adenocarcinoma

Introduction: Exosomes have pivotal roles in cancer development. The impact of neoadjuvant concurrent chemoradiation (NCCR) on exosomal markers (CD63 and CD9) expression and their prognostic significance in patients with rectal adenocarcinoma are yet to be explored.

Materials and Methods: Between 2015 and 2018, 33 patients had rectal adenocarcinoma treated with NCCR and had pre-NCCR biopsy and post-NCCR resected rectum. CD63 and CD9 expression was assessed by immunohistochemistry (IHC). The short-term surrogate endpoint neoadjuvant rectal (NAR) score was used for assessment of prognostic significance. Un-Paired t-test was used for statistical analysis.

Results: The mean tumor CD63 and CD9 scores in pre-NCCR biopsy vs. post-NCCR resected rectum were 106 vs. 165 (P = 0.0022) and 136 vs. 215 (P < 0.0001) respectively. The mean tumor CD63 and CD9 scores respectively in pre-NCCR biopsy was 99 and 130 in patients with low-intermediate NAR score compared to 117 and 144 in patients with high NAR score (P = 0.4934) (P = 0.5519). The mean tumor CD63 and CD9 scores respectively in post-NCCR resected rectum was 155 and 205 in patients with low-intermediate NAR score compared to 180 and 230 in patients with high NAR score (P = 0.3793) (P = 0.2837).

Conclusions: The expression of the exosomal markers (CD63 and CD9) increased in patients with rectal adenocarcinoma after treatment with NCCR. The exosomal markers (CD63 and CD9) may have a prognostic significance. There was a trend for higher CD63 and CD9 expression in patients with high NAR score compared with low-intermediate NAR scores. The lack of statistical significance is likely due to the small sample size.

Emerging role of tumor microenvironment derived exosomes in therapeutic resistance and metastasis through epithelial-to-mesenchymal transition

The tumor microenvironment (TME) constitutes multiple cell types including cancerous and non-cancerous cells. The intercellular communication between these cells through TME derived exosomes may either enhance or suppress the tumorigenic processes. The tumor-derived exosomes could convert an anti-tumor environment into a pro-tumor environment by inducing the differentiation of stromal cells into tumor-associated cells. The exosomes from tumor-associated stromal cells reciprocally trigger epithelial-to-mesenchymal transition (EMT) in tumor cells, which impose therapeutic resistance and metastasis. It is well known that these exosomes contain the signals of EMT, but how these signals execute chemoresistance and metastasis in tumors remains elusive. Understanding the significance and molecular signatures of exosomes transmitting EMT signals would aid in developing appropriate methods of inhibiting them. In this review, we focus on molecular signatures of exosomes that shuttle between cancer cells and their stromal populations in TME to explicate their impact on therapeutic resistance and metastasis through EMT. Especially Wnt signaling is found to be involved in multiple ways of exosomal transport and hence we decipher the biomolecules of Wnt signaling trafficked through exosomes and their potential in serving as therapeutic targets.

Microvesicles - promising tiny players' of cancer stem cells targeted liver cancer treatments: The interesting interactions and therapeutic aspects

Liver cancer is one of the most malignant cancers worldwide with poor prognosis. Intracellular mediators like microvesicles (MVs) and cancer stem cells (CSCs) are considered as potential candidates in liver cancer progression. CSCs receive stimuli from the tumor microenvironment to initiate tumor formation in which it's secreted MVs play a noteworthy role. The phenotypic conversion of tumor cells during epithelial-to-mesenchymal transition (EMT) is a key step in tumor invasion and metastasis which indicates that the diverse cell populations within the primary tumor are in a dynamic balance and can be regulated by cell to cell communication via secreted microvesicles. Thus, in this review, we aim to highlight the evidences that suggest CSCs are crucial for liver cancer development where the microvesicles plays an important part in the maintenance of its stemness properties. In addition, we summarize the existing evidences that support the concept of microvesicles, the tiny particles have a big role behind the rare immortal CSCs which controls the tumor initiation, propagation and metastasis in liver cancer. Identifying interactions between CSCs and microvesicles may offer new insights into precise anti-cancer therapies in the future.

Autophagy and Exosomes Relationship in Cancer: Friends or Foes?

Autophagy is an intracellular degradation process involved in the removal of proteins and damaged organelles by the formation of a double-membrane vesicle named autophagosome and degraded through fusion with lysosomes. An intricate relationship between autophagy and the endosomal and exosomal pathways can occur at different stages with important implications for normal physiology and human diseases. Recent researches have revealed that extracellular vesicles (EVs), such as exosomes, could have a cytoprotective role by inducing intracellular autophagy; on the other hand, autophagy plays a crucial role in the biogenesis and degradation of exosomes. Although the importance of these processes in cancer is well established, their interplay in tumor is only beginning to be documented. In some tumor contexts (1) autophagy and exosome-mediated release are coordinately activated, sharing the molecular machinery and regulatory mechanisms; (2) cancer cell-released exosomes impact on autophagy in recipient cells through mechanisms yet to be determined; (3) exosome-autophagy relationship could affect drug resistance and tumor microenvironment (TME). In this review, we survey emerging discoveries relevant to the exosomes and autophagy crosstalk in the context of cancer initiation, progression and recurrence. Consequently, we discuss clinical implications by targeting autophagy-exosomal pathway interaction and how this could lay a basis for the purpose of novel cancer therapeutics.

Real-time tracking of bacterial membrane vesicles reveals enhanced membrane traffic upon antibiotic exposure

Membrane vesicles are ubiquitous carriers of molecular information. A broad understanding of the biological functions of membrane vesicles in bacteria remains elusive because of the imaging challenges during real-time in vivo experiments. Here, we provide a quantitative analysis of the motion of individual vesicles in living microbes using fluorescence microscopy, and we show that while vesicle free diffusion in the intercellular space is rare, vesicles mostly disperse along the bacterial surfaces. Most remarkably, when bacteria are challenged with low doses of antibiotics, vesicle production and traffic, quantified by instantaneous vesicle speeds and total traveled distance per unit time, are significantly enhanced. Furthermore, the enhanced vesicle movement is independent of cell clustering properties but rather is associated with a reduction of the density of surface appendages in response to antibiotics. Together, our results provide insights into the emerging field of spatial organization and dynamics of membrane vesicles in microcolonies.

Therapy-induced chemoexosomes: Sinister small extracellular vesicles that support tumor survival and progression

Chemotherapy involves the use of multiple cytotoxic or cytostatic drugs acting by various mechanisms to kill or arrest the growth of cancer cells. Chemotherapy remains the most utilized approach for controlling cancer. Emerging evidence indicates that cancer cells activate various pro-survival mechanisms to cope with chemotherapeutic stress. These mechanisms persist during treatment and often help orchestrate tumor regrowth and patient relapse. Exosomes due to their nature of carrying and transferring multiple biologically active components have emerged as key players in cancer pathogenesis. Recent data demonstrates that chemotherapeutic stress enhances the secretion and alters the cargo carried by exosomes. These altered exosomes, which we refer to as chemoexosomes, are capable of transferring cargo to target tumor cells that can enhance their chemoresistance, increase their metastatic behavior and in certain cases even aid in endowing tumor cells with cancer stem cell-like properties. This mini-review summarizes the recent developments in our understanding of the impact chemoexosomes have on tumor survival and progression.

Signal Transduction Pathways Activated by Innate Immunity in Mast Cells: Translating Sensing of Changes into Specific Responses

Mast cells (MCs) constitute an essential cell lineage that participates in innate and adaptive immune responses and whose phenotype and function are influenced by tissue-specific conditions. Their mechanisms of activation in type I hypersensitivity reactions have been the subject of multiple studies, but the signaling pathways behind their activation by innate immunity stimuli are not so well described. Here, we review the recent evidence regarding the main molecular elements and signaling pathways connecting the innate immune receptors and hypoxic microenvironment to cytokine synthesis and the secretion of soluble or exosome-contained mediators in this cell type. When known, the positive and negative control mechanisms of those pathways are presented, together with their possible implications for the understanding of mast cell-driven chronic inflammation. Finally, we discuss the relevance of the knowledge about signaling in this cell type in the recognition of MCs as central elements on innate immunity, whose remarkable plasticity converts them in sensors of micro-environmental discontinuities and controllers of tissue homeostasis.

Extracellular Vesicles in the Development of the Non-Alcoholic Fatty Liver Disease: An Update

Non-alcoholic fatty liver disease (NAFLD) is a broad spectrum of liver damage disease from a simple fatty liver (steatosis) to more severe liver conditions such as non-alcoholic steatohepatitis (NASH), fibrosis, and cirrhosis. Extracellular vesicles (EVs) are a heterogeneous group of small membrane vesicles released by various cells in normal or diseased conditions. The EVs carry bioactive components in their cargos and can mediate the metabolic changes in recipient cells. In the context of NAFLD, EVs derived from adipocytes are implicated in the development of whole-body insulin resistance (IR), the hepatic IR, and fatty liver (steatosis). Excessive fatty acid accumulation is toxic to the hepatocytes, and this lipotoxicity can induce the release of EVs (hepatocyte-EVs), which can mediate the progression of fibrosis via the activation of nearby macrophages and hepatic stellate cells (HSCs). In this review, we summarized the recent findings of adipocyte- and hepatocyte-EVs on NAFLD disease development and progression. We also discussed previous studies on mesenchymal stem cell (MSC) EVs that have garnered attention due to their effects on preventing liver fibrosis and increasing liver regeneration and proliferation.

Extracellular Vesicle-Based Communication May Contribute to the Co-Evolution of Cancer Stem Cells and Cancer-Associated Fibroblasts in Anti-Cancer Therapy

Analogously to the natural selective forces in ecosystems, therapies impose selective pressure on cancer cells within tumors. Some tumor cells can adapt to this stress and are able to form resistant subpopulations, parallel with enrichment of cancer stem cell properties in the residual tumor masses. However, these therapy-resistant cells are unlikely to be sufficient for the fast tumor repopulation and regrowth by themselves. The dynamic and coordinated plasticity of residual tumor cells is essential both for the conversion of their regulatory network and for the stromal microenvironment to produce cancer supporting signals. In this nursing tissue "niche", cancer-associated fibroblasts are known to play crucial roles in developing therapy resistance and survival of residual stem-like cells. As paracrine messengers, extracellular vesicles carrying a wide range of signaling molecules with oncogenic potential, can support the escape of some tumor cells from their deadly fate. Here, we briefly overview how extracellular vesicle signaling between fibroblasts and cancer cells including cancer progenitor/stem cells may contribute to the progression, therapy resistance and recurrence of malignant tumors.

Exosomal MiR-500a-3p promotes cisplatin resistance and stemness via negatively regulating FBXW7 in gastric cancer

Chemoresistance has been a major challenge in advanced gastric cancer (GC) therapy. Exosomal transfer of oncogenic miRNAs implicates important effects in mediating recipient cell chemoresistance by transmitting active molecules. In this study, we found that microRNA‐500a‐3p was highly expressed in cisplatin (DDP) resistant GC cells (MGC803/DDP and MKN45/DDP) and their secreted exosomes than that in the corresponding parental cells. MGC803/DDP‐derived exosomes enhance DDP resistance and stemness properties of MGC803 recipient cells via exosomal delivery of miR‐500a‐3p in vitro and in vivo through targeting FBXW7. However, reintroduction of FBXW7 in MGC803 cells reverses miR‐500a‐3p‐mediated DDP resistance as well as stemness properties. Furthermore, elevated miR‐500a‐3p in the plasma exosomes of GC patients is correlated with DDP resistance and thereby results in poor progression‐free prognosis. Our finding highlights the potential of exosomal miR‐500a‐3p as an potential modality for the prediction and treatment of GC with chemoresistance.

Fibroblast‑derived exosomal microRNA‑369 potentiates migration and invasion of lung squamous cell carcinoma cells via NF1‑mediated MAPK signaling pathway

Cancer-associated fibroblasts (CAFs) exhibit tumor-stimulating properties and are associated with poor survival in several types of cancer, making them potential therapeutic targets. The present study aimed to determine whether CAFs were associated with cell migration and invasion in lung squamous cell carcinoma (LUSC), as well as their association with microRNA-369 (miR-369) in these processes. Firstly, the changes of the malignant biological behavior were observed by treating the LUSC cells with the CAFs-derived extracellular vesicles (CAFs-EVs). Subsequently, the differentially expressed miRNAs in the cells treated with CAFs-EVs were analyzed by microarray analysis. Following inhibition of miR-369 expression in CAFs-EVs, LUSC cells were co-cultured, and the malignant biological behavior of the cells was re-examined. Then, through bioinformatics analysis and verification, the mRNA targets of miR-369 and the corresponding downstream signaling pathway were screened out. Finally, the effects of CAFs-EVs on the growth and metastasis of LUSC were demonstrated by in vivo tumor formation and metastasis experiments. It was identified that miR-369 was expressed at a relatively high level in the CAFs-EVs. Neurofibromin-1 (NF1) was hypothesized as a direct target of miR-369 in LUSC. Also, the overexpression of miR-369 activated the mitogen-activated protein kinase signaling pathway by interacting with NF1, consequently potentiating LUSC cell growth. The present study provided novel insights into the action of miR-369 in CAFs-EVs in controlling LUSC cell migration, invasion and tumorigenesis, and identified miR-369 in CAFs-EVs as an important prognostic marker and therapeutic target.