Proteomic analysis of exosomes reveals an association between cell invasiveness and exosomal bioactivity on endothelial and mesenchymal cell migration in vitro

Enhancing precision targeting of ovarian cancer tumor cells in vivo through extracellular vesicle engineering

Extracellular vesicles (EVs) function as natural mediators of intercellular communication, secreted by cells to facilitate cell-cell signaling. Due to their low toxicity, immunogenicity, biodegradability, and potential to encapsulate therapeutic drugs, EVs hold significant therapeutic promise. Nevertheless, their limited targeting ability often diminishes their therapeutic impact. Therefore, enhancing EVs by incorporating targeting units onto their membranes could bolster their targeting capabilities, enabling them to accumulate in specific cells and tissues. In this study, we engineered EVs to fuse ephrin-B2 with the EV membrane protein LAMP2b. This modification aimed to direct the engineered EVs toward the ephrin-B4 receptor expressed on the surface of ovarian cancer cells. The engineered EVs retained their inherent properties, including size, expression of EV membrane proteins, and morphology, upon isolation. In vitro experiments using real-time imaging revealed that EVs engineered with the ephrin-B2 ligand exhibited substantial internalization and uptake by ovarian cancer cells, in stark contrast to native EVs. In vivo, the engineered EVs carrying the ephrin-B2 ligand effectively targeted ovarian cancer cells, surpassing the targeting efficiency of control EVs. This innovative approach establishes a novel targeting system, enhancing the uptake of EVs by ovarian cancer cells. Our findings underscore the potential of using EVs to target cancer cells, thereby enhancing the effectiveness of anti-cancer therapies while minimizing off-target effects and toxicity in normal cells and organs.

The role of extracellular vesicles from placenta and endometrium in pregnancy: Insights from tumor biology

Extracellular vesicles (EVs) are small membrane-bound particles secreted by various cell types that play a critical role in intercellular communication by packaging and delivering biomolecules. In recent years, EVs have emerged as essential messengers in mediating physiological and pathological processes in tumor biology. The tumor microenvironment (TME) plays a pivotal role in tumor generation, progression, and metastasis. In this review, we provide an overview of the impact of tumor-derived EVs on both tumor cells and the TME. Moreover, we draw parallels between tumor biology and pregnancy, as successful embryo implantation also requires intricate intercellular communication between the placental trophecepiblast and the endometrial epithelium. Additionally, we discuss the involvement of EVs in targeting immune responses, trophoblast invasion, migration, and angiogenesis, which are shared biological processes between tumors and pregnancy. Specifically, we highlight the effects of placenta-derived EVs on the fetal-maternal interface, placenta, endometrium, and maternal system, as well as the role of endometrium-derived EVs in embryo-endometrial communication. However, challenges still exist in EVs research, including the standardization of EVs isolation methods for diagnostic testing, which also apply to reproductive systems where EVs-mediated communication is proposed to take place. Through this review, we aim to deepen the understanding of EVs, particularly in the context of reproductive biology, and encourage further investigation in this field.

Scientific and clinical relevance of non-cellular tumor microenvironment components in ovarian cancer chemotherapy resistance

The tumor microenvironment (TME) components play a crucial role in cancer cells' resistance to chemotherapeutic agents. This phenomenon is exceptionally fundamental in patients with ovarian cancer (OvCa), whose outcome depends mainly on their response to chemotherapy. Until now, most reports have focused on the role of cellular components of the TME, while less attention has been paid to the stroma and other non-cellular elements of the TME, which may play an essential role in the therapy resistance. Inhibiting these components could help define new therapeutic targets and potentially restore chemosensitivity. The aim of the present article is both to summarize the knowledge about non-cellular components of the TME in the development of OvCa chemoresistance and to suggest targeting of non-cellular elements of the TME as a valuable strategy to overcome chemoresistance and to develop new therapeutic strategies in OvCA patients.

Metabolomics profiling and chemoresistance mechanisms in ovarian cancer cell lines: Implications for targeting glutathione pathway

Ovarian cancer presents a significant challenge due to its high rate of chemoresistance, which complicates the effectiveness of drug-response therapy. This study provides a comprehensive metabolomic analysis of ovarian cancer cell lines OVCAR-3 and SK-OV-3, characterizing their distinct metabolic landscapes. Metabolomics coupled with chemometric analysis enabled us to discriminate between the metabolic profiles of these two cell lines. The OVCAR-3 cells, which are sensitive to doxorubicin (DOX), exhibited a preference for biosynthetic pathways associated with cell proliferation. Conversely, DOX-resistant SK-OV-3 cells favored fatty acid oxidation for energy maintenance. Notably, a marked difference in glutathione (GSH) metabolism was observed between these cell lines. Our investigations further revealed that GSH depletion led to a profound change in drug sensitivity, inducing a shift from a cytostatic to a cytotoxic response. The results derived from this comprehensive metabolomic analysis offer potential targets for novel therapeutic strategies to overcome drug resistance. Our study suggests that targeting the GSH pathway could potentially enhance chemotherapy's efficacy in treating ovarian cancer.

A comprehensive review on the composition, biogenesis, purification, and multifunctional role of exosome as delivery vehicles for cancer therapy

All forms of life produce nanosized extracellular vesicles called exosomes, which are enclosed in lipid bilayer membranes. Exosomes engage in cell-to-cell communication and participate in a variety of physiological and pathological processes. Exosomes function via their bioactive components, which are delivered to target cells in the form of proteins, nucleic acids, and lipids. Exosomes function as drug delivery vehicles due to their unique properties of innate stability, low immunogenicity, biocompatibility, biodistribution, accumulation in desired tissues, low toxicity in normal tissues, and the stimulation of anti-cancer immune responses, and penetration capacity into distance organs. Exosomes mediate cellular communications by delivering various bioactive molecules including oncogenes, oncomiRs, proteins, specific DNA, messenger RNA (mRNA), microRNA (miRNA), small interfering RNA (siRNA), and circular RNA (circRNA). These bioactive substances can be transferred to change the transcriptome of target cells and influence tumor-related signaling pathways. After considering all of the available literature, in this review we discuss the biogenesis, composition, production, and purification of exosomes. We briefly review exosome isolation and purification techniques. We explore great-length exosomes as a mechanism for delivering a variety of substances, including proteins, nucleic acids, small chemicals, and chemotherapeutic drugs. We also talk about the benefits and drawbacks of exosomes. This review concludes with a discussion future perspective and challenges. We hope that this review will provide us a better understanding of the current state of nanomedicine and exosome applications in biomedicine.

The diagnostic and therapeutic prospects of exosomes in ovarian cancer

Exosomes are nano-sized vesicles derived from the endosomal system and are involved in many biological and pathological processes. Emerging evidence has demonstrated that exosomes with cell-specific constituents are associated with the tumorigenesis and progression of ovarian cancer. Therefore, exosomes derived from ovarian cancers can be potential diagnostic biomarkers and therapeutic targets. In this review, we briefly present the biological characteristics of exosomes and the recent advances in isolating and detecting exosomes. Furthermore, we summarise the many functions of exosomes in ovarian cancer, hoping to provide a theoretical basis for clinical applications of exosomes in the diagnosis and treatment of ovarian cancer.

Endothelial plasticity across PTEN and Hippo pathways: A complex hormetic rheostat modulated by extracellular vesicles

Vascularization is a multifactorial and spatiotemporally regulated process, essential for cell and tissue survival. Vascular alterations have repercussions on the development and progression of diseases such as cancer, cardiovascular diseases, and diabetes, which are the leading causes of death worldwide. Additionally, vascularization continues to be a challenge for tissue engineering and regenerative medicine. Hence, vascularization is the center of interest for physiology, pathophysiology, and therapeutic processes. Within vascularization, phosphatase and tensin homolog deleted on chromosome 10 (PTEN) and Hippo signaling have pivotal roles in the development and homeostasis of the vascular system. Their suppression is related to several pathologies, including developmental defects and cancer. Non-coding RNAs (ncRNAs) are among the regulators of PTEN and/or Hippo pathways during development and disease. The purpose of this paper is to review and discuss the mechanisms by which exosome-derived ncRNAs modulate endothelial cell plasticity during physiological and pathological angiogenesis, through the regulation of PTEN and Hippo pathways, aiming to establish new perspectives on cellular communication during tumoral and regenerative vascularization.

Extracellular Vesicles-ceRNAs as Ovarian Cancer Biomarkers: Looking into circRNA-miRNA-mRNA Code

Simple Summary

Patients with ovarian cancer have a very poor chance of long-term survival, usually due to advanced disease at the time of diagnosis. Emerging evidence suggests that extracellular vesicles contain noncoding RNAs such as microRNAs, piwiRNAs, circular RNAs, and long noncoding RNAs, with regulatory effects on ovarian cancer. In this review, we focus on ovarian cancer-associated circular RNA shuttled by extracellular vesicles as mediators of cancer progression and novel biomarkers in liquid biopsy. We propose a circular-RNA–microRNA-mRNA code that can reveal the regulatory network created by extracellular vesicles, noncoding RNAs, and mRNAs in ovarian cancer. Future research in this field will help to identify novel diagnostic biomarkers and druggable therapeutic targets, which will ultimately benefit patients.

Abstract

Ovarian cancer (OC) is one of the most lethal gynecologic malignancies in females worldwide. OC is frequently diagnosed at an advanced stage due to a lack of specific symptoms and effective screening tests, resulting in a poor prognosis for patients. Age, genetic alterations, and family history are the major risk factors for OC pathogenesis. Understanding the molecular mechanisms underlying OC progression, identifying new biomarkers for early detection, and discovering potential targets for new drugs are urgent needs. Liquid biopsy (LB), used for cancer detection and management, consists of a minimally invasive approach and practical alternative source to investigate tumor alterations by testing extracellular vesicles (EVs), circulating tumor cells, tumor-educated platelets, and cell-free nucleic acids. EVs are nanosize vesicles shuttling proteins, lipids, and nucleic acids, such as DNA, RNA, and non-coding RNAs (ncRNAs), that can induce phenotypic reprogramming of target cells. EVs are natural intercellular shuttles for ncRNAs, such as microRNAs (miRNAs) and circular-RNAs (circRNAs), known to have regulatory effects in OC. Here we focus on the involvement of circRNAs and miRNAs in OC cancer progression. The circRNA-microRNA-mRNA axis has been investigated with Circbank and miRwalk analysis, unraveling the intricate and detailed regulatory network created by EVs, ncRNAs, and mRNAs in OC.

Tumor-Derived Exosomes Modulate Primary Site Tumor Metastasis

Tumor-derived exosomes (TDEs) are actively produced and released by tumor cells and carry messages from tumor cells to healthy cells or abnormal cells, and they participate in tumor metastasis. In this review, we explore the underlying mechanism of action of TDEs in tumor metastasis. TDEs transport tumor-derived proteins and non-coding RNA to tumor cells and promote migration. Transport to normal cells, such as vascular endothelial cells and immune cells, promotes angiogenesis, inhibits immune cell activation, and improves chances of tumor implantation. Thus, TDEs contribute to tumor metastasis. We summarize the function of TDEs and their components in tumor metastasis and illuminate shortcomings for advancing research on TDEs in tumor metastasis.

Characteristics and regulation of mesenchymal stem cell plasticity by the microenvironment — specific factors involved in the regulation of MSC plasticity

Mesenchymal stem cells (MSCs), multipotent stromal cells, have attracted extensive attention in the field of regenerative medicine and cell therapy due to the capacity of self-renewal, multilineage differentiation, and immune regulation. MSCs have different cellular effects in different diseases, and even have markedly different curative effects with different tissue sources, indicating the plasticity of MSCs. The phenotypes, secreted factors, and proliferative, migratory, differentiating, and immunomodulatory effects of MSCs depend on certain mediators present in their microenvironment. Understanding microenvironmental factors and their internal mechanisms in MSC responses may help in subsequent prediction and improvement of clinical benefits. This review highlighted the recent advances in MSC plasticity in the physiological and pathological microenvironment and multiple microenvironmental factors regulating MSC plasticity. It also highlighted some progress in the underlying molecular mechanisms of MSC remodeling in the microenvironment. It might provide references for the improvement in vitro culture of MSCs, clinical application, and in vivo induction.

Prognostic utility of the ovarian cancer secretome: a systematic investigation

BACKGROUND

Ovarian cancer is usually detected at an advanced stage with frequent recurrence. The recurrence-free survival and overall survival is influenced by the age at diagnosis, tumor stage and histological subtype. Nonetheless, quantifiable prognostic biomarkers are needed for early identification of the high-risk patients and for personalized medicine. Several studies link tumor-specific dysregulated expression of certain proteins with ovarian cancer prognosis. However, careful investigation of presence of these prognostically relevant proteins in ovarian cancer secretome is lacking.

OBJECTIVE

To critically analyze the recent published data on prognostically relevant proteins for ovarian cancer and to carefully search how many of them are reported in the published ovarian cancer secretome datasets.

DESIGN

A search for relevant studies in the past 2 years was conducted in PubMed and a comprehensive list of proteins associated with the ovarian cancer prognosis was prepared. These were cross-referred to the published ovarian cancer secretome profiles. The proteins identified in the secretome were further shortlisted based on a scoring strategy employing stringent criteria.

RESULTS

A panel of seven promising secretory biomarkers associated with ovarian cancer prognosis is proposed.

CONCLUSION

Scanning the ovarian cancer secretome datasets provides the opportunity to identify if tumor-specific biomarkers could be tested as secretory biomarkers. Detecting their levels in the body fluid would be more advantageous than evaluating the expression in the tissue, since it could be monitored multiple times over the course of the disease to have a better judgment of the prognosis and response to therapy.

Extracellular vesicles in ovarian cancer chemoresistance, metastasis, and immune evasion

Chemoresistance and metastasis are the major challenges for the current ovarian cancer treatment. Understanding the mechanisms of ovarian cancer progression and metastasis is critically important for developing novel therapies. The advances in extracellular vesicles (EVs) research in recent years have attracted extensive attention. EVs contain a variety of proteins, RNAs, DNAs, and metabolites. Accumulating evidence indicates that ovarian cancer cells secrete a large amount of EVs, playing an important role in tumor progression and recurrence. In the microenvironment of ovarian tumor, EVs participate in the information transmission between stromal cells and immune cells, promoting the immune escape of ovarian cancer cells and facilitating cancer metastasis. Here, we review the recent advances of EVs in chemoresistance, mechanisms of metastasis, and immune evasion of ovarian cancer. Furthermore, we also discuss the challenges of EV research and future application of EVs as promising biomarker sources in response to therapy and in therapy-delivery approaches for ovarian cancer patients.

Ovarian-Cancer-Associated Extracellular Vesicles: Microenvironmental Regulation and Potential Clinical Applications

Ovarian cancer (OC) is one of the most diagnosed gynecological cancers in women. Due to the lack of effective early stage screening, women are more often diagnosed at an advanced stage; therefore, it is associated with poor patient outcomes. There are a lack of tools to identify patients at the highest risk of developing this cancer. Moreover, early detection strategies, therapeutic approaches, and real-time monitoring of responses to treatment to improve survival and quality of life are also inadequate. Tumor development and progression are dependent upon cell-to-cell communication, allowing cancer cells to re-program cells not only within the surrounding tumor microenvironment, but also at distant sites. Recent studies established that extracellular vesicles (EVs) mediate bi-directional communication between normal and cancerous cells. EVs are highly stable membrane vesicles that are released from a wide range of cells, including healthy and cancer cells. They contain tissue-specific signaling molecules (e.g., proteins and miRNA) and, once released, regulate target cell phenotypes, inducing a pro-tumorigenic and immunosuppressive phenotype to contribute to tumor growth and metastasis as well as proximal and distal cell function. Thus, EVs are a “fingerprint” of their cell of origin and reflect the metabolic status. Additionally, via the capacity to evade the immune system and remain stable over long periods in circulation, EVs can be potent therapeutic agents. This review examines the potential role of EVs in the different aspects of the tumor microenvironment in OC, as well as their application in diagnosis, delivery of therapeutic agents, and disease monitoring.

Extracellular Vesicle Transmission of Chemoresistance to Ovarian Cancer Cells Is Associated with Hypoxia-Induced Expression of Glycolytic Pathway Proteins, and Prediction of Epithelial Ovarian Cancer Disease Recurrence

Simple Summary

Ovarian cancer is one of the most lethal cancers affecting women worldwide. Its high mortality rate is often attributed to the non-specific nature of early symptoms of the disease. Developing a better understanding of the disease progression and identifying clinically useful biomarkers that aid in clinical management are requisite to reducing the mortality rate of ovarian cancer. Reduced oxygen tension (i.e., hypoxia) is not only a characteristic of solid tumors but may also enhance the metastatic capacity of tumors by inducing the release of tumor growth promoting factors. Recently, it has been proposed that small tumor-derived extracellular vesicles (sEVs) facilitate cancer progression. In this study, we established that sEVs produced under low oxygen tension induce a metabolic switch in ovarian cancer cells associated with changes in glycolytic pathway proteins that promote resistance to carboplatin. Significantly, we identified a suite of sEV-associated glycolysis pathway proteins that are present in patients with ovarian cancer that can predict disease recurrence with over 90% accuracy.

Abstract

Hypoxia is a key regulator of cancer progression and chemoresistance. Ambiguity remains about how cancer cells adapt to hypoxic microenvironments and transfer oncogenic factors to surrounding cells. In this study, we determined the effects of hypoxia on the bioactivity of sEVs in a panel of ovarian cancer (OvCar) cell lines. The data obtained demonstrate a varying degree of platinum resistance induced in OvCar cells when exposed to low oxygen tension (1% oxygen). Using quantitative mass spectrometry (Sequential Window Acquisition of All Theoretical Fragment Ion Mass Spectra, SWATH) and targeted multiple reaction monitoring (MRM), we identified a suite of proteins associated with glycolysis that change under hypoxic conditions in cells and sEVs. Interestingly, we identified a differential response to hypoxia in the OvCar cell lines and their secreted sEVs, highlighting the cells’ heterogeneity. Proteins are involved in metabolic reprogramming such as glycolysis, including putative hexokinase (HK), UDP-glucuronosyltransferase 1–6 (UD16), and 6-phosphogluconolactonase (6 PGL), and their presence correlates with the induction of platinum resistance. Furthermore, when normoxic cells were exposed to sEVs from hypoxic cells, platinum-resistance increased significantly (p < 0.05). Altered chemoresistance was associated with changes in glycolysis and fatty acid synthesis. Finally, sEVs isolated from a clinical cohort (n = 31) were also found to be enriched in glycolysis-pathway proteins, especially in patients with recurrent disease. These data support the hypothesis that hypoxia induces changes in sEVs composition and bioactivity that confers carboplatin resistance on target cells. Furthermore, we propose that the expression of sEV-associated glycolysis-pathway proteins is predictive of ovarian cancer recurrence and is of clinical utility in disease management.

Role of exosomes in the immune microenvironment of ovarian cancer

Exosomes are excretory vesicles that can deliver a variety of bioactive cargo molecules to the extracellular environment. Accumulating evidence demonstrates exosome participation in intercellular communication, immune response, inflammatory response and they even play an essential role in affecting the tumor immune microenvironment. The role of exosomes in the immune microenvironment of ovarian cancer is mainly divided into suppression and stimulation. On one hand exosomes can stimulate the innate and adaptive immune systems by activating dendritic cells (DCs), natural killer cells and T cells, allowing these immune cells exert an antitumorigenic effect. On the other hand, ovarian cancer-derived exosomes initiate cross-talk with immunosuppressive effector cells, which subsequently cause immune evasion; one of the hallmarks of cancer. Exosomes induce the polarization of macrophages in M2 phenotype and induce apoptosis of lymphocytes and DCs. Exosomes further activate additional immunosuppressive effector cells (myeloid-derived suppressor cells and regulatory T cells) that induce fibroblasts to differentiate into cancer-associated fibroblasts. Exosomes also induce the tumorigenicity of mesenchymal stem cells to exert additional immune suppression. Furthermore, besides mediating the intercellular communication, exosomes carry microRNAs (miRNAs), proteins and lipids to the tumor microenvironment, which collectively promotes ovarian cancer cells to proliferate, invade and tumors to metastasize. Studying proteins, lipids and miRNAs carried by exosomes could potentially be used as an early diagnostic marker of ovarian cancer for designing treatment strategies.

Bone marrow mesenchymal stem cells-derived exosomal microRNA-19b-1-5p reduces proliferation and raises apoptosis of bladder cancer cells via targeting ABL2

BACKGROUND

Exosomes are involved in intercellular communication via specialized molecular cargo, such as microRNAs (miRNAs). However, the mechanisms underlying exosomal miR-19b-1-5p in bladder cancer remain largely unknown, thus, we aim to investigate the effect of exosomal miR-19b-1-5p on bladder cancer with the involvement of non-receptor protein tyrosine kinase Arg (ABL2).

METHODS

miR-19b-1-5p and ABL2 expression were tested in bladder cancer. miR-19b-1-5p inhibition/elevation assays were conducted to determine its role in bladder cancer. Exosomes were extracted from bone marrow mesenchymal stem cells (BMSCs). Exosomes and T24 cells were co-cultured to verify their function in biological characteristics of bladder cancer cells.

RESULTS

miR-19b-1-5p was down-regulated while ABL2 was upregulated in bladder cancer. Exosomal miR-19b-1-5p suppressed malignant behaviors of bladder cancer cells, and also inhibited tumor growth in vivo. Up-regulated ABL2 mitigated the effects of miR-19b-1-5p up-regulation on bladder cancer cells.

CONCLUSION

BMSCs-derived exosomal miR-19b-1-5p suppresses bladder cancer growth via decreasing ABL2.

Total Blood Exosomes in Breast Cancer: Potential Role in Crucial Steps of Tumorigenesis

Exosomes are crucial players in cell-to-cell communication and are involved in tumorigenesis. There are two fractions of blood circulating exosomes: free and cell-surface-associated. Here, we compared the effect of total blood exosomes (contain plasma exosomes and blood cell-surface-associated exosomes) and plasma exosomes from breast cancer patients (BCPs, n = 43) and healthy females (HFs, n = 35) on crucial steps of tumor progression. Exosomes were isolated by ultrafiltration, followed by ultracentrifugation, and characterized by cryo-electron microscopy (cryo-EM), nanoparticle tracking analysis, and flow cytometry. Cryo-EM revealed a wider spectrum of exosome morphology with lipid bilayers and vesicular internal structures in the HF total blood in comparison with plasma. No differences in the morphology of both exosomes fractions were detected in BCP blood. The plasma exosomes and total blood exosomes of BCPs had different expression levels of tumor-associated miR-92a and miR-25-3p, induced angiogenesis and epithelial-to-mesenchymal transition (EMT), and increased the number of migrating pseudo-normal breast cells and the total migration path length of cancer cells. The multidirectional effects of HF total blood exosomes on tumor dissemination were revealed; they suppress the angiogenesis and total migration path length of MCF10A, but stimulate EMT and increase the number of migrating MCF10A and the total path length of SKBR3 cells. In addition, HF plasma exosomes enhance the metastasis-promoting properties of SKBR3 cells and stimulate angiogenesis. Both cell-free and blood cell-surface-associated exosomes are involved in the crucial stages of carcinogenesis: the initiation of EMT and the stimulation of proliferation, cell migration, and angiogenesis. Thus, for the estimation of the diagnostic/prognostic significance of circulating exosomes in the blood of cancer patients more correctly, the total blood exosomes, which consist of plasma exosomes and blood cell-surface-associated exosomes should be used.

Uptake and Fate of Extracellular Membrane Vesicles: Nucleoplasmic Reticulum-Associated Late Endosomes as a New Gate to Intercellular Communication

Extracellular membrane vesicles (EVs) are emerging as new vehicles in intercellular communication, but how the biological information contained in EVs is shared between cells remains elusive. Several mechanisms have been described to explain their release from donor cells and the initial step of their uptake by recipient cells, which triggers a cellular response. Yet, the intracellular routes and subcellular fate of EV content upon internalization remain poorly characterized. This is particularly true for EV-associated proteins and nucleic acids that shuttle to the nucleus of host cells. In this review, we will describe and discuss the release of EVs from donor cells, their uptake by recipient cells, and the fate of their cargoes, focusing on a novel intracellular route wherein small GTPase Rab7⁺ late endosomes containing endocytosed EVs enter into nuclear envelope invaginations and deliver their cargo components to the nucleoplasm of recipient cells. A tripartite protein complex composed of (VAMP)-associated protein A (VAP-A), oxysterol-binding protein (OSBP)-related protein-3 (ORP3), and Rab7 is essential for the transfer of EV-derived components to the nuclear compartment by orchestrating the particular localization of late endosomes in the nucleoplasmic reticulum.

Pulp-Derived Exosomes in a Fibrin-Based Regenerative Root Filling Material

Regenerative endodontics has been described as a paradigm shift in dentistry, despite its current limitation to immature teeth and reparative rather than regenerative outcomes. Cell-free treatments are favored because of regulatory issues. However, the recruitment of host-derived stem cells to the desired site remains challenging. We investigated whether dental pulp-derived exosomes, which are extracellular vesicles that contain proteins, lipids, RNA, and DNA and thus mirror their parental cells, may be used for this purpose. The use of exosomes may present appreciable advantages over the direct use of transplanted stem cells due to a higher safety profile, easier isolation, preservation, and handling. Here we harvested exosomes from a cultured third-molar pulp cell and assessed them by transmission electron microscopy and Western blotting. Human mesenchymal stem cells (MSCs) were exposed to these exosomes to assess exosome uptake, cell migration, and proliferation. In addition, a fibrin gel (i.e., a diluted fibrin sealant), was assessed as a delivery system for the exosomes. Our results show that exosomes attracted MSCs, and the fibrin gel enhanced their effect. Moreover, exosomes improved the proliferation of MSCs. Therefore, we propose that pulp-derived exosomes in combination with a fibrin gel could be a powerful combination for clinical translation towards improved cell-free regenerative endodontics and thus represent a new way to fill dental hard tissues.

MicroRNAs in ovarian cancer and recent advances in the development of microRNA-based biosensors

Ovarian cancer is the most aggressive of all gynaecological malignancies and is the leading cause of cancer-associated mortality worldwide.

Techniques Associated with Exosome Isolation for Biomarker Development: Liquid Biopsies for Ovarian Cancer Detection

Ovarian cancer is the leading gynecological malignancy worldwide. This is attributed to the fact that the disease is often diagnosed at an advanced stage, where the survival rates drop from approximately 90% (detection at an early stage) to 20%. Furthermore, ovarian cancer is not associated with overt physical symptoms. Thus, there is an urgent need for a highly sensitive and minimally invasive biomarker for the early detection of ovarian cancer. However, this continues to remain an unmet clinical need, as several proposed techniques have shown low sensitivity and specificity, with poor positive and negative predictive values. The quest for an ideal biomarker has bought exosomes to the forefront. Exosomes are small extracellular vesicles of an endocytic origin, which can encapsulate genetic information, in the form of proteins and miRNAs. They are released by multiple cell types and are involved in intercellular communication, through the transfer of their cargo. The process of exosome biogenesis allows for the packaging of molecules from both membranous and cytosolic origins. Therefore, exosomes are representations of the releasing cell, and thus provide an insight into the cellular environment. Furthermore, exosomal encapsulation of molecules such as proteins and miRNAs can prevent degradation, making exosomes an ideal biomarker source. Thus, this chapter provides an overview of ovarian cancer, the potential of exosomes as an early detection biomarker, and the different methods associated with the isolation of different vesicle subpopulations, and exosome enrichment.

Exosomes promote pre-metastatic niche formation in ovarian cancer

Ovarian cancer is one of the most common gynecological malignancies. Upon initial diagnosis, the majority of patients present with widespread metastatic growth within the peritoneal cavity. This metastatic growth occurs in stages, with the formation of a pre-metastatic niche occurring prior to macroscopic tumor cell invasion. Exosomes released by the primary ovarian tumor are small extracellular vesicles which prepare the distant tumor microenvironment for accelerated metastatic invasion. They regulate intercellular communication between tumor cells and normal stroma, cancer-associated fibroblasts, and local immune cells within the tumor microenvironment. In this review, we highlight the emerging roles of ovarian cancer exosomes as coordinators of pre-metastatic niche formation, biomarkers amenable to liquid biopsy, and targets of chemotherapy.

Ovarian cancer-derived exosomes promote tumour metastasis in vivo: an effect modulated by the invasiveness capacity of their originating cells

Exosomes are small nanovesicles that carry bioactive molecules which can be delivered to neighbouring cells to modify their biological functions. Studies have showed that exosomes from ovarian cancer (OVCA) cells can alter the cell migration and proliferation of cells within the tumour microenvironment, an effect modulated by the invasiveness capacity of their originating cells. Using an OVCA cell line xenograph mouse model, we showed that exosomes derived from a high invasiveness capacity cell line (exo-SKOV-3) promoted metastasis in vivo compared with exosomes from a low invasiveness capacity cell line (exo-OVCAR-3). Analysis from anin vivo imaging system (IVIS) revealed that exo-SKOV-3 formed metastatic niches, whereas exo-OVCAR-3 formed colonies of clustered cells close to the site of injection. Interestingly, kinetic parameters showed that the half-maximal stimulatory time (ST₅₀) of tumour growth with exo-OVCAR-3 (4.0 ± 0.31 weeks) was significantly lower compared with the ST₅₀ in mice injected with exo-SKOV-3 (4.5 ± 0.32 weeks). However, the number of metastic nodes in mice injected with exo-SKOV-3 was higher compared with exo-OVCAR-3. Using a quantitative mass spectrometry approach (SWATH MS/MS) followed by bioinformatics analysis using the Ingenuity Pathway Analysis (IPA), we identified a total of 771 proteins. Furthermore, 40 of these proteins were differentially expressed in tumour tissues from mice injected with exo-SKOV-3 compared with exo-OVCAR-3, and associated with Wnt canonical pathway (β-catenin). Finally, we identified a set of proteins which had elevated expression in the circulating exosomes in association with tumour metastasis. These observations suggest that exosomal signalling plays an important role in OVCA metastasis.

Involvement of Extracellular Vesicles in Vascular-Related Functions in Cancer Progression and Metastasis

The primary cause of mortality among patients with cancer is the progression of the tumor, better known as cancer invasion and metastasis. Cancer progression involves a series of biologically important steps in which the cross-talk between cancer cells and the cells in the surrounding environment is positioned as an important issue. Notably, angiogenesis is a key tumorigenic phenomenon for cancer progression. Cancer-related extracellular vesicles (EVs) commonly contribute to the modulation of a microenvironment favorable to cancer cells through their function of cell-to-cell communication. Vascular-related cells such as endothelial cells (ECs) and platelets activated by cancer cells and cancer-derived EVs develop procoagulant and proinflammatory statuses, which help excite the tumor environment, and play major roles in tumor progression, including in tumor extravasation, tumor cell microthrombi formation, platelet aggregation, and metastasis. In particular, cancer-derived EVs influence ECs, which then play multiple roles such as contributing to tumor angiogenesis, loss of endothelial vascular barrier by binding to ECs, and the subsequent endothelial-to-mesenchymal transition, i.e., extracellular matrix remodeling. Thus, cell-to-cell communication between cancer cells and ECs via EVs may be an important target for controlling cancer progression. This review describes the current knowledge regarding the involvement of EVs, especially exosomes derived from cancer cells, in EC-related cancer progression.