The Biology of Exosomes in Breast Cancer Progression: Dissemination, Immune Evasion and Metastatic Colonization

Glutamate molecular structure and protein affect the inhibition of breast cancer cell metastasis: Cell-derived exosomes inhibitory effects through the MAPK signaling pathway

The aim of this study was to investigate the inhibitory effect of glutamate molecular structure and protein on breast cancer cell metastasis and the potential inhibitory mechanism of cell-derived exosomes via MAPK signaling pathway. Breast cancer cell lines with high metastatic potential were selected by in vitro cell culture technique. The effects of specific inhibitors of glutamic acid on the proliferation and metastasis of breast cancer cells were studied. Changes in protein expression profiles were analyzed by proteomics techniques to identify key proteins associated with breast cancer metastasis. Breast cancer cells were treated with inhibitors of the MAPK signaling pathway to evaluate their effect on cell metastasis and compare with exosome treatment. The results showed that the specific inhibitors of glutamate molecular structure could significantly inhibit the proliferation and metastasis of breast cancer cells. Proteomic analysis revealed several down-regulated proteins that are closely related to breast cancer metastasis.

The Role of Small Extracellular Vesicles in Retinoblastoma Development and Progression

A growing body of research on extracellular vesicles (EVs) in cancer has revealed their novel and crucial activities in the progression of tumors while also paving the way for potential therapeutic interventions. It is now known that EVs are natural delivery vehicles for particular payloads of source cells, enabling them to influence diverse functions of cells both in healthy and malignant cells. In this review, we comprehensively summarize mechanistic insights into sEV roles in RB, the most frequent intraocular malignancy that affects the retina of young children. We also explore the therapeutic potential of sEVs as an emerging area as biomarkers and vehicles for targeted therapy. Additionally, we address the potential challenges and limitations of translating sEVs-based technologies into clinical practice.

Biological Cargo: Exosomes and their Role in Cancer Progression and Metastasis

Cancer cells are among the many types of cells that release exosomes, which are nanovesicles. Because of their many potential applications, exosomes have recently garnered much attention from cancer researchers. The bioactive substances that exosomes release as cargo have been the subject of several investigations. The substances in question may operate as biomarkers for diagnosis or affect apoptosis, the immune system, the development and spread of cancer, and other processes. Others have begun to look at exosomes in experimental therapeutic trials because they believe they may be useful in the treatment of cancer. This review started with a short description of exosome biogenesis and key features. Next, the potential of tumor-derived exosomes and oncosomes to influence the immune system throughout the development of cancer, as well as alter tumor microenvironments (TMEs) and pre-metastatic niche creation, was investigated. Finally, there was talk of exosomes' possible use in cancer treatment. Furthermore, there is emerging consensus about the potential application of exosomes to be biological reprogrammers of cancer cells, either as carriers of naturally occurring chemicals, including anticancer medications, or as carriers of anticancer vaccines for immunotherapy as well as boron neutron capture therapy (BNCT). We briefly review the key ideas and logic behind this intriguing therapy recommendation.

Rational design of a poly-L-glutamic acid-based combination conjugate for hormone-responsive breast cancer treatment

Breast cancer represents the most prevalent tumor type worldwide, with hormone-responsive breast cancer the most common subtype. Despite the effectiveness of endocrine therapy, advanced disease forms represent an unmet clinical need. While drug combination therapies remain promising, differences in pharmacokinetic profiles result in suboptimal ratios of free drugs reaching tumors. We identified a synergistic combination of bisdemethoxycurcumin and exemestane through drug screening and rationally designed star-shaped poly-L-glutamic acid-based combination conjugates carrying these drugs conjugated through pH-responsive linkers for hormone-responsive breast cancer treatment. We synthesized/characterized single and combination conjugates with synergistic drug ratios/loadings. Physicochemical characterization/drug release kinetics studies suggested that lower drug loading prompted a less compact conjugate conformation that supported optimal release. Screening in monolayer and spheroid breast cancer cell cultures revealed that combination conjugates possessed enhanced cytotoxicity/synergism compared to physical mixtures of single-drug conjugates/free drugs; moreover, a combination conjugate with the lowest drug loading outperformed remaining conjugates. This candidate inhibited proliferation-associated signaling, reduced inflammatory chemokine/exosome levels, and promoted autophagy in spheroids; furthermore, it outperformed a physical mixture of single-drug conjugates/free drugs regarding cytotoxicity in patient-derived breast cancer organoids. Our findings highlight the importance of rational design and advanced in vitro models for the selection of polypeptide-based combination conjugates.

Targeting tumor-associated macrophages with nanocarrier-based treatment for breast cancer: A step toward developing innovative anti-cancer therapeutics

Tumor-associated macrophages (TAMs) promote tumor advancement in many ways, such as inducing angiogenesis and the formation of new blood vessels that provide tumors with nourishment and oxygen. TAMs also facilitate tumor invasion and metastasis by secreting enzymes that degrade the extracellular matrix and generating pro-inflammatory cytokines that enhance the migration of tumor cells. TAMs also have a role in inhibiting the immune response against malignancies. To accomplish this, they release immunosuppressive cytokines such as IL-10, and TAMs can hinder the function of T cells and natural killer cells, which play crucial roles in the immune system's ability to combat cancer. The role of TAMs in breast cancer advancement is a complex and dynamic field of research. Therefore, TAMs are a highly favorable focus for innovative breast cancer treatments. This review presents an extensive overview of the correlation between TAMs and breast cancer development as well as its role in the tumor microenvironment (TME) shedding light on their impact on tumor advancement and immune evasion mechanisms. Notably, our study provides an innovative approach to employing nanomedicine approaches for targeted TAM therapy in breast cancer, providing an in-depth overview of recent advances in this emerging field.

Elevated extracellular vesicular Nm23-H1 subdues the pro-migratory potential of breast cancer cell-derived extracellular vesicles

Metastasis is a key determinant in cancer mortality which is often associated with decreased levels of Nm23-H1, a well-established metastasis suppressor. Despite lacking a secretion signal peptide, Nm23-H1 has been reported to be present in the extracellular space and enclosed within extracellular vesicles (EVs). While the presence of Nm23-H1 proteins in EVs released by cancer cells has been observed through proteomics profiling, the role of vesicular Nm23-H1 remains unclear. Here, we investigated the function of vesicular Nm23-H1 using MDA-MB-231 (highly metastatic, low Nm23-H1) and MCF-7 (low/non-metastatic, high Nm23-H1) breast cancer cell models. Our findings confirm that Nm23-H1 is indeed encapsulated within EVs, and its levels can be manipulated through overexpression and knockdown approaches. Functional assays revealed that EVs derived from MDA-MB-231 cells that contained high levels of Nm23-H1 exhibit impaired pro-migratory properties, suggesting that vesicular Nm23-H1 may act as a metastasis suppressor. Furthermore, EVs with increased levels of Nm23-H1 altered the transcript levels of multiple cancer-related genes in recipient cells and stimulated type I interferon signaling through STAT1 phosphorylation. These results suggest the existence of an unconventional signaling pathway mediated by the uptake of EVs enriched with Nm23-H1, which may contribute to the anti-metastatic effect of Nm23-H1 in the tumor microenvironment. Additionally, our study demonstrates that elevated Nm23-H1 levels can impact the abundance of various other proteins encapsulated within breast cancer cell-derived EVs, such as SUSD2 (Sushi Domain Containing 2) which can also modulate metastasis.

Therapeutic implications of signaling pathways and tumor microenvironment interactions in esophageal cancer

Esophageal cancer (EC) is significantly influenced by the tumor microenvironment (TME) and altered signaling pathways. Downregulating these pathways in EC is essential for suppressing tumor development, preventing metastasis, and enhancing therapeutic outcomes. This approach can increase tumor sensitivity to treatments, enhance patient outcomes, and inhibit cancer cell proliferation and spread. The TME, comprising cellular and non-cellular elements surrounding the tumor, significantly influences EC's development, course, and treatment responsiveness. Understanding the complex relationships within the TME is crucial for developing successful EC treatments. Immunotherapy is a vital TME treatment for EC. However, the heterogeneity within the TME limits the application of anticancer drugs outside clinical settings. Therefore, identifying reliable microenvironmental biomarkers that can detect therapeutic responses before initiating therapy is crucial. Combining approaches focusing on EC signaling pathways with TME can enhance treatment outcomes. This integrated strategy aims to interfere with essential signaling pathways promoting cancer spread while disrupting factors encouraging tumor development. Unraveling aberrant signaling pathways and TME components can lead to more focused and efficient treatment approaches, identifying specific cellular targets for treatments. Targeting the TME and signaling pathways may reduce metastasis risk by interfering with mechanisms facilitating cancer cell invasion and dissemination. In conclusion, this integrative strategy has significant potential for improving patient outcomes and advancing EC research and therapy. This review discusses the altered signaling pathways and TME in EC, focusing on potential future therapeutics.

Exosomes isolated from metabolically unhealthy normal weight and overweight phenotypes deteriorate the ER/PR positive breast cancer behavior

Purpose

Obesity has been linked to a higher risk of postmenopausal breast cancer Yet, research indicates an opposite correlation between obesity and premenopausal breast cancer risk. Various obesity phenotypes based on metabolic health could play a significant part. This study aims to assess how plasma exosomes taken from women with varying obesity phenotypes impact MCF-7 cell migration, matrix metalloproteinase-2 activity, and apoptosis.

Methods

The characterization of isolated exosomes and their internalization into MCF-7 cells was evaluated. The treatment of MCF-7 cells with exosomes isolated from different groups was done. Migration, the activity of MMP-2, mRNA expression of Bax and Bcl-2, protein expression of p-53 and Thr55 p-p53, and apoptosis were assessed.

Results

Isolated exosomes from unhealthy obese individuals increase MCF-7 cell migration. Regarding MMP activities, unhealthy normal weight and overweight and healthy obese groups isolated exosomes increase the MMP-2 activity than the treated group with exosomes isolated from counterpart groups. Furthermore, unhealthy normal weight and overweight and healthy obese obtained exosomes decrease apoptosis compared to counterpart groups.

Conclusion

Altogether, plasma exosomes derived from both unhealthy individuals with normal weight and overweight status, as well as those with unhealthy obesity, negatively impacted the behavior of estrogen/progesterone receptor-positive breast cancer cells.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40200-023-01295-1.

Extracellular vesicle-mediated drug delivery in breast cancer theranostics

Breast cancer (BC) continues to be a significant global challenge due to drug resistance and severe side effects. The increasing prevalence is alarming, requiring new therapeutic approaches to address these challenges. At this point, Extracellular vesicles (EVs), specifically small endosome-released nanometer-sized EVs (SEVs) or exosomes, have been explored by literature as potential theranostics. Therefore, this review aims to highlight the therapeutic potential of exosomes in BC, focusing on their advantages in drug delivery and their ability to mitigate metastasis. Following the review, we identified exosomes' potential in combination therapies, serving as miRNA carriers and contributing to improved anti-tumor effects. This is evident in clinical trials investigating exosomes in BC, which have shown their ability to boost chemotherapy efficacy by delivering drugs like paclitaxel (PTX) and doxorubicin (DOX). However, the translation of EVs into BC therapy is hindered by various challenges. These challenges include the heterogeneity of EVs, the selection of the appropriate parent cell, the loading procedures, and determining the optimal administration routes. Despite the promising therapeutic potential of EVs, these obstacles must be addressed to realize their benefits in BC treatment.

Breast cancer derived exosomes: Theragnostic perspectives and implications

Breast cancer (BC) is the most prevalent malignancy affecting women worldwide. Although conventional treatments such as chemotherapy, surgery, hormone therapy, radiation therapy, and biological therapy are commonly used, they often entail significant side effects. Therefore, there is a critical need to investigate more cost-effective and efficient treatment modalities in BC. Extracellular vesicles (EVs), including exosomes, microvesicles, and apoptotic bodies, play a crucial role in modulating recipient cell behaviour and driving cancer progression. Among the EVs, exosomes provide valuable insights into cellular dynamics under both healthy and diseased conditions. In cancer, exosomes play a critical role in driving tumor progression and facilitating the development of drug resistance. BC-derived exosomes (BCex) dynamically influence BC progression by regulating cell proliferation, immunosuppression, angiogenesis, metastasis, and the development of treatment resistance. Additionally, BCex serve as promising diagnostic markers in BC which are detectable in bodily fluids such as urine and saliva. Targeted manipulation of BCex holds significant therapeutic potential. This review explores the therapeutic and diagnostic implications of exosomes in BC, underscoring their relevance to the disease. Furthermore, it discusses future directions for exosome-based research in BC, emphasizing the necessity for further exploration in this area.

Exploring the dynamic interplay between exosomes and the immune tumor microenvironment: implications for breast cancer progression and therapeutic strategies

Breast cancer continues to pose a substantial worldwide health concern, demanding a thorough comprehension of the complex interaction between cancerous cells and the immune system. Recent studies have shown the significant function of exosomes in facilitating intercellular communication and their participation in the advancement of cancer. Tumor-derived exosomes have been identified as significant regulators in the context of breast cancer, playing a crucial role in modulating immune cell activity and contributing to the advancement of the illness. This study aims to investigate the many effects of tumor-derived exosomes on immune cells in the setting of breast cancer. Specifically, we will examine their role in influencing immune cell polarization, facilitating immunological evasion, and modifying the tumor microenvironment. Furthermore, we explore the nascent domain of exosomes produced from immune cells and their prospective involvement in the prevention of breast cancer. This paper focuses on new research that emphasizes the immunomodulatory characteristics of exosomes produced from immune cells. It also explores the possibility of these exosomes as therapeutic agents or biomarkers for the early identification and prevention of breast cancer. The exploration of the reciprocal connections between exosomes formed from tumors and immune cells, together with the rising significance of exosomes derived from immune cells, presents a potential avenue for the advancement of novel approaches in the field of breast cancer therapy and prevention.

Protocol to separate small and large extracellular vesicles from mouse and human cardiac tissues

Extracellular vesicles (EVs) are secreted by cells under various conditions and can contribute to the disease progression in tissues. Here, we present a protocol to separate small and large EVs from mouse hearts and cardiac tissues collected from patients. We describe steps for utilizing enzymatic digestion for release of EVs from interstitial space followed by differential centrifugation and immunoaffinity purification. The isolated EVs can be used for various experiments to gain insight into their in vivo functions. For complete details on the use and execution of this protocol, please refer to Liang et al. (2023).1.

Extracellular vesicles in the breast cancer brain metastasis: physiological functions and clinical applications

Breast cancer, which exhibits an increasing incidence and high mortality rate among cancers, is predominantly attributed to metastatic malignancies. Brain metastasis, in particular, significantly contributes to the elevated mortality in breast cancer patients. Extracellular vesicles (EVs) are small lipid bilayer vesicles secreted by various cells that contain biomolecules such as nucleic acids and proteins. They deliver these bioactive molecules to recipient cells, thereby regulating signal transduction and protein expression levels. The relationship between breast cancer metastasis and EVs has been extensively investigated. In this review, we focus on the molecular mechanisms by which EVs promote brain metastasis in breast cancer. Additionally, we discuss the potential of EV-associated molecules as therapeutic targets and their relevance as early diagnostic markers for breast cancer brain metastasis.

miRNAs in the Box: Potential Diagnostic Role for Extracellular Vesicle-Packaged miRNA-27a and miRNA-128 in Breast Cancer

Circulating extracellular vesicle (EV)-derived microRNAs (miRNAs) are now considered the next generation of cancer "theranostic" tools, with strong clinical relevance. Although their potential in breast cancer diagnosis has been widely reported, further studies are still required to address this challenging issue. The present study examined the expression profiles of EV-packaged miRNAs to identify novel miRNA signatures in breast cancer and verified their diagnostic accuracy. Circulating EVs were isolated from healthy controls and breast cancer patients and characterized following the MISEV 2018 guidelines. RNA-sequencing and real-time PCR showed that miRNA-27a and miRNA-128 were significantly down-regulated in patient-derived EVs compared to controls in screening and validation cohorts. Bioinformatics analyses of miRNA-target genes indicated several enriched biological processes/pathways related to breast cancer. Receiver operating characteristic (ROC) curves highlighted the ability of these EV-miRNAs to distinguish breast cancer patients from non-cancer controls. According to other reports, the levels of EV-miRNA-27a and EV-miRNA-128 are not associated with their circulating ones. Finally, evidence from the studies included in our systematic review underscores how the expression of these miRNAs in biofluids is still underinvestigated. Our findings unraveled the role of serum EV-derived miRNA-27a and miRNA-128 in breast cancer, encouraging further investigation of these two miRNAs within EVs towards improved breast cancer detection.

RETRACTED: Potential Protective Role of Melatonin in Benign Mammary Cells Reprogrammed by Extracellular Vesicles from Malignant Cells

(1) Background: Mammary neoplasms in female dogs share many similarities with the same tumor class in humans, rendering these animals a valuable preclinical model for studying novel therapies against breast cancer. The intricate role of extracellular vesicles (EVs), particularly exosomes, in breast carcinogenesis, by transferring specific proteins to recipient cells within the tumor microenvironment, underscores their significance. Melatonin, a hormone recognized for its antitumor effects, adds another layer of intrigue. (2) Methods: EVs obtained from the plasma of dogs diagnosed with mammary tumors were co cultivated with the benign epithelial lineage E-20 using DMEM. The experiment comprised four 24 h treatment groups: control, EVs, melatonin, and EVs + melatonin. A series of assays were conducted, including colony formation, proliferation, and cellular migration assessments. Furthermore, we conducted colony formation, proliferation, and cellular migration assays. We performed immunohistochemistry for proteins of the mTOR pathway, including mTOR and AKT. (3) Results: Exosomes alone significantly increased proliferation, migration, and colony formation rates and, upregulated the expression of mTOR and AKT proteins. However, when melatonin was added, a protective effect was observed. (4) Conclusions: These findings contributed to the use of melatonin to modulate EV-mediated signaling in the clinical veterinary oncology of mammary tumors.

Exosomal miRNAs and breast cancer: a complex theranostics interlink with clinical significance

Breast cancer (BC) remains the most challenging global health crisis of the current decade, impacting a large population of females annually. In the field of cancer research, the discovery of extracellular vesicles (EVs), specifically exosomes (a subpopulation of EVs), has marked a significant milestone. In general, exosomes are released from all active cells but tumour cell-derived exosomes (TDXs) have a great impact (TDXs miRNAs, proteins, lipid molecules) on cancer development and progression. TDXs regulate multiple events in breast cancer such as tumour microenvironment remodelling, immune cell suppression, angiogenesis, metastasis (EMT-epithelial mesenchymal transition, organ-specific metastasis), and therapeutic resistance. In BC, early detection is the most challenging event, exosome-based BC screening solved the problem. Exosome-based BC treatment is a sign of the transforming era of liquid biopsy, it is also a promising therapeutic tool for breast cancer. Exosome research goes to closer precision oncology via a single exosome profiling approach. Our hope is that this review will serve as motivation for researchers to explore the field of exosomes and develop an efficient, and affordable theranostics approach for breast cancer.

Chemotherapy-induced exosomal circBACH1 promotes breast cancer resistance and stemness via miR-217/G3BP2 signaling pathway

BACKGROUND

Chemoresistance involves metastasis and aggressiveness of breast cancer (BC). Chemotherapy-elicited exosomes have been reported to be associated with drug resistance and pro-metastatic capacity of BC cells. Non-coding RNAs (ncRNAs) are enriched in exosomes, which participated in generation, progression, and resistance of BC. However, the mechanism underlying the chemoresistance and metastasis in BC cells mediated by the BC-derived exosomal ncRNAs remained to be elucidated.

METHODS

The effects of PTX-induced exosomal circBACH1 on BC cell function were assessed using RNA Binding Protein Immunoprecipitation (RIP), dual luciferase reporter gene, tube formation, CCK-8, and Western Blot assays. The circBACH1 and miR-217 expression levels were detected using quantitative real-time PCR (RT-qPCR) and Immunohistochemistry (IHC) assays in BC tissues and precancerous tissues of BC patients.

RESULTS

CircBACH1 expression was increased in paclitaxel-treated BC-derived exosomes (PTX-EXO) and BC tissue. PTX-EXO was shown to promote PTX-resistance and angiogenesis through upregulation circBACH1. Downregulation of circBACH1 improved PTX-sensitiveness by suppressing the cell viability, stemness, migration, and angiogenesis of BC cells. Moreover, we found that miR-217 interacted with circBACH1 and targeted GTPase-activating SH3 domain-binding protein 2 (G3BP2) in BC cells. CircBACH1 combined miR-217 cotransfection suppressed the expression of G3BP2 proteins compared with circBACH1 treatment in MCF-7 cells. In addition, downregulation of G3BP2 suppressed BC cell migration.

CONCLUSIONS

These results demonstrated that PTX-induced exosomal circBACH1 promoted stemness and migration of BC cells by sponging miR-217 to upregulate the expression of G3BP2, which provided a new therapeutic target for PTX-resistance and progression of BC via circBACH1/miR-217/G3BP2 axis.

Polarization of Cancer-Associated Macrophages Maneuver Neoplastic Attributes of Pancreatic Ductal Adenocarcinoma

Mounting evidence links the phenomenon of enhanced recruitment of tumor-associated macrophages towards cancer bulks to neoplastic growth, invasion, metastasis, immune escape, matrix remodeling, and therapeutic resistance. In the context of cancer progression, naïve macrophages are polarized into M1 or M2 subtypes according to their differentiation status, gene signatures, and functional roles. While the former render proinflammatory and anticancer effects, the latter subpopulation elicits an opposite impact on pancreatic ductal adenocarcinoma. M2 macrophages have gained increasing attention as they are largely responsible for molding an immune-suppressive landscape. Through positive feedback circuits involving a paracrine manner, M2 macrophages can be amplified by and synergized with neighboring neoplastic cells, fibroblasts, endothelial cells, and non-cell autonomous constituents in the microenvironmental niche to promote an advanced disease state. This review delineates the molecular cues expanding M2 populations that subsequently convey notorious clinical outcomes. Future therapeutic regimens shall comprise protocols attempting to abolish environmental niches favoring M2 polarization; weaken cancer growth typically assisted by M2; promote the recruitment of tumoricidal CD8⁺ T lymphocytes and dendritic cells; and boost susceptibility towards gemcitabine as well as other chemotherapeutic agents.

The impact of lipid metabolism on breast cancer: a review about its role in tumorigenesis and immune escape

BACKGROUND

Breast cancer (BC) is the second most frequent type of cancer in the world and most common among women, configuring a major challenge to global health. BC is a complex and heterogeneous disease that can be subdivided into distinct tumor types based on the expression of molecular markers predicting patient outcomes and response to therapy. A growing number of studies have tried to expand the known markers by investigating the association of altered lipid metabolism with BC immune escape, progression, and metastasis. In this review, we describe the metabolic peculiarities of each BC subtype, understanding how this influences its aggressiveness and identifying whether these intrinsic vulnerabilities of each subtype can play a role in therapeutic management and may affect immune system cells in the tumor microenvironment.

CONCLUSION

The evidence suggests so far that when changes occur in lipid pathways, it can affect the availability of structural lipids for membrane synthesis, lipid synthesis, and degradation that contribute to energy homeostasis and cell signaling functions. These findings will guide the next steps on the path to understanding the mechanisms underlying how lipids alterations are related to disparities in chemotherapeutic response and immune escape in BC. Video Abstract.

The Emerging Biological Functions of Exosomes from Dental Tissue-Derived Mesenchymal Stem Cells

Exosomes are one kind of small-cell extracellular membranous vesicles that can regulate intercellular communication and give rise to mediating the biological behaviors of cells, involving in tissue formation, repair, the modulation of inflammation, and nerve regeneration. The abundant kinds of cells can secret exosomes, among them, mesenchymal stem cells (MSCs) are very perfect cells for mass production of exosomes. Dental tissue-derived mesenchymal stem cells (DT-MSCs), including dental pulp stem cells, stem cells from exfoliated deciduous teeth, stem cells from apical papilla, stem cells from human periodontal ligament (PDLSCs), gingiva-derived mesenchymal stem cells, dental follicle stem cells, tooth germ stem cells, and alveolar bone-derived mesenchymal stem cells, are now known as a potent tool in the area of cell regeneration and therapy, more importantly, DT-MSCs can also release numerous types of exosomes, participating in the biological functions of cells. Hence, we briefly depict the characteristics of exosomes, give a detailed description of the biological functions and clinical application in some respects of exosomes from DT-MSCs through systematically reviewing the latest evidence, and provide a rationale for their use as tools for potential application in tissue engineering.

Analysis of circulating extracellular vesicle derived microRNAs in breast cancer patients with obesity: a potential role for Let-7a

BACKGROUND

The incidence of obesity, a known risk factor for several metabolic and chronic diseases, including numerous malignancies, has risen sharply in the world. Various clinical studies demonstrate that excessive Body Mass Index (BMI) may worsen the incidence, prognosis, and mortality rates of breast cancer. Thus, understanding the link tying up obesity and breast cancer onset and progression is critically important, as it can impact patients' survival and quality of life. Recently, circulating extracellular vesicle (EV) derived miRNAs have attracted much attention for their diagnostic, prognostic and therapeutic potential in oncology research. Although the potential role of EV-derived miRNAs in the early detection of breast cancer has been repeatedly mentioned, screening of miRNAs packaged within serum EVs has not yet been reported in patients with obesity.

METHODS

Circulating EVs were isolated from normal weight (NW), and overweight/obese (OW/Ob) breast cancer patients and characterized by Transmission Electron Microscopy (TEM), Nanoparticle Tracking Analysis (NTA), and protein marker expression. Evaluation of EV-associated miRNAs was conducted in a screening (RNA-seq) and a validation (qRT-PCR) cohort. Bioinformatic analysis was performed to uncover significantly enriched biological processes, molecular functions and pathways. ROC and Kaplain-Meier survival analyses were used for clinical significance.

RESULTS

Comparison of serum EV-derived miRNAs from NW and OW/Ob patients detected seven differentially expressed miRNAs (let-7a-5p, miR-122-5p, miR-30d-5p, miR-126-3p, miR-27b-3p, miR-4772-3p, and miR-10a-5p) in the screening cohort. GO analysis revealed the enrichment of protein phosphorylation, intracellular signal transduction, signal transduction, and vesicle-mediated transport among the top biological processes. In addition, the target genes were significantly enriched in pathways related to PI3K/Akt, growth hormones, and insulin signalings, which are all involved in obesity-related diseases and/or breast cancer progression. In the validation cohort, qRT-PCR confirmed a significant down-regulation of EV-derived let-7a in the serum of OW/Ob breast cancer patients compared to NW patients. Let-7a levels also exhibited a negative correlation with BMI values. Importantly, decreased let-7a miRNA expression was associated with higher tumor grade and poor survival in patients with breast cancer.

CONCLUSION

These results suggest that serum-EV derived miRNAs may reflect a differential profile in relation to a patient's BMI, which, once validated in larger cohorts of patients, could provide insights into novel specific biomarkers and innovative targets to prevent the progression of obesity-mediated breast cancer.

Comparative Proteomics Analysis of Exosomes Identifies Key Pathways and Protein Markers Related to Breast Cancer Metastasis

Proteomics analysis of circulating exosomes derived from cancer cells represents a promising approach to the elucidation of cell-cell communication and the discovery of putative biomarker candidates for cancer diagnosis and treatment. Nonetheless, the proteome of exosomes derived from cell lines with different metastatic capabilities still warrants further investigation. Here, we present a comprehensive quantitative proteomics investigation of exosomes isolated from immortalized mammary epithelial cells and matched tumor lines with different metastatic potentials in an attempt to discover exosome markers specific to breast cancer (BC) metastasis. A total of 2135 unique proteins were quantified with a high confidence level from 20 isolated exosome samples, including 94 of the TOP 100 exosome markers archived by ExoCarta. Moreover, 348 altered proteins were observed, among which several metastasis-specific markers, including cathepsin W (CATW), magnesium transporter MRS2 (MRS2), syntenin-2 (SDCB2), reticulon-4 (RTN), and UV excision repair protein RAD23 homolog (RAD23B), were also identified. Notably, the abundance of these metastasis-specific markers corresponds well with the overall survival of BC patients in clinical settings. Together, these data provide a valuable dataset for BC exosome proteomics investigation and prominently facilitate the elucidation of the molecular mechanisms underlying primary tumor development and progression.

Biochemistry of exosomes and their theranostic potential in human diseases

Exosomes are classified as special extracellular vesicles in the eukaryotic system having diameters ranging from 30 to 120 nm. These vesicles carry various endogenous molecules including DNA, mRNA, microRNA, circular RNA, and proteins, crucial for numerous metabolic reactions and can be proposed as therapeutic or diagnostic targets for several disorders. The donor exosomes release their content to recipient cells and further establish the significant intercellular communication showing biological effects by triggering environmental alterations. Exosomes derived from mesenchymal and dendritic cells have demonstrated their therapeutic potential against organ injury. Yet, various intricacies are involved in exosomal transport and its inclusion in cancer and other disease pathogenesis needs to be explored. The exosomes represent profound potential as diagnostic biomarkers and therapeutic carriers in various pathophysiological conditions such as neurodegenerative diseases, chronic cancers, infectious diseases, female reproductive diseases and cardiovascular diseases. In the current study, we demonstrate the advancements in the implication of exosomes as one of the irrefutable prognostic biological targets in human health and diseases.

The application of tumor cell-derived vesicles in oncology therapy

Tumor cell-derived vesicles are released by tumor cells, have a phospholipid bilayer, and are widely distributed in various biological fluids. In recent years, it has been found that tumor cell-derived vesicles contain proteins, metabolites and nucleic acids and can be delivered to recipient cells to perform their physiological functions, such as mediating specific intercellular communication, activating or inhibiting signaling pathways, participating in regulating the modulation of tumor microenvironment and influencing tumor development, which can be used for early detection and diagnosis of cancer. In addition, tumor cell-derived vesicles exhibit multiple properties in tumor therapeutic applications and may serve as a new class of delivery systems. In this review, we elaborate on the application of tumor cell-derived vesicles in oncology therapy.

Glypican-3 Differentiates Intraductal Carcinoma and Paget's Disease from Other Types of Breast Cancer

Background and Objectives: breast cancer remains the most common health burden affecting females worldwide. Despite developments in breast cancer diagnostic approaches and treatment strategies, the clinical management of metastatic breast cancer remains challenging. Thus, there is a need to identify new biomarkers and novel drug targets for breast cancer diagnosis and therapy. Recently, aberrant glypican-3 (GPC3) expression in cancers has gained considerable interest in cancer research. The studies, however, have yielded contradictory results about GPC3 expression in breast cancer. Therefore, the current study aims to analyse GPC3 expression across a large panel of different breast cancer subtypes. Materials and Methods: GPC3 expression was immunohistochemically evaluated in 230 breast cancer patients along with eight normal tissues and its associations to clinical and demographic characteristics, as well as immunohistochemical biomarkers for breast cancer. Moreover, a public database consisting of breast cancer patients' survival data and GPC3 gene expression information was used to assess the prognostic value of GPC3 in the survival of breast cancer patients. Results: GPC3 expression was only characterised in 7.5% of different histological breast cancer subtypes. None of the normal breast tissues displayed GPC3 expression. Interestingly, all cases of Paget's disease, as well as 42.9% of intraductal and 16.7% of mucinous carcinomas were found to have GPC3 expression, where it was able to significantly discriminate Paget's disease and intraductal carcinoma from other breast cancer subtypes. Importantly, GPC3 expression was found more often in tumours that tested positive for the expression of hormone receptors and human epidermal growth factor receptor 2 (HER2), indicating more favourable histological subtypes of breast cancer. Consequently, longer relapse-free survival (RFS) was significantly correlated with higher GPC3 mRNA expression. Conclusions: Our study proposes that GPC3 is a promising breast cancer subtype-specific biomarker. Moreover, GPC3 may have the potential to be a molecular target for the development of new therapeutics for specific subtypes of breast cancer.

Downregulation of exosomal miR-7-5p promotes breast cancer migration and invasion by targeting RYK and participating in the atypical WNT signalling pathway

Background

Current studies show that exosomal miRNAs become an important factor in cancer metastasis. Among the many miRNA studies, miR-7-5p has not been thoroughly investigated in breast cancer metastasis.

Methods

Bioinformatic screening was performed using extant data from the GEO database, and miR-7-5p expression levels in breast cancer cell lines and exosomes were further examined using real-time quantitative PCR (qRT-PCR). The extracted exosomes were characterised by transmission electron microscopy (TEM), particle size analysis and marker protein determination. Cell migration and invasion were then examined using wound healing assays and Transwell assays, respectively. Correlation between miR-7-5p and receptor-like tyrosine kinase (RYK) was analysed by luciferase reporter. The effect of miR-7-5p against RYK-related downstream factors was verified using western blot assays.

Results

In this study, we found that the expression of miR-7-5p was significantly different in exosomes secreted from breast cancer cell lines with different high and low invasiveness. Further experiments revealed that miR-7-5p has an important role in inhibiting the migration and invasion of breast cancer. In terms of mechanism of action, miR-7-5p was found to target the RYK, leading to its reduced expression, which in turn caused a reduction in the phosphorylation level of the downstream factor JNK. Reduced levels of phosphorylated JNK factors lead to reduced levels of phosphorylation of c-Jun protein, which in turn leads to increased expression of EMT transcription factors, thereby inhibiting the epithelial–mesenchymal transition (EMT) process to suppress the invasion of breast cancer.

Conclusion

Thus, we demonstrated that exosomes loaded with high levels of miR-7-5p emitted from less aggressive breast cancers can participate in the atypical WNT pathway by targeting the RYK gene and thus inhibit breast cancer metastasis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s11658-022-00393-x.

Proteomic Profiling of Extracellular Vesicles Released by Leptin-Treated Breast Cancer Cells: A Potential Role in Cancer Metabolism

Tumor extracellular vesicles (EVs), as endocytic vesicles able to transport nucleic acids, proteins, and metabolites in recipient cells, have been recognized fundamental mediators of cell-to-cell communication in breast cancer. The biogenesis and release of EVs are highly regulated processes and both the quantity of EVs and their molecular cargo might reflect the metabolic state of the producing cells. We recently demonstrated that the adipokine leptin, whose circulating levels correlate with adipose tissue expansion, is an inducer of EV release from breast cancer cells. Here, we show a specific proteomic signature of EVs released by MCF-7 breast cancer cells grown in the presence of leptin (Lep-EVs), in attempt to find additional molecular effectors linking obesity to breast cancer biology. An analysis of the proteomic profile of Lep-EVs by LC-MS/MS revealed a significant enrichment in biological processes, molecular functions, and cellular components mainly related to mitochondrial machineries and activity, compared to protein content of EVs from untreated breast cancer cells. Metabolic investigations, carried out to assess the autocrine effects of these vesicles on breast cancer cells, revealed that Lep-EVs were able to increase ATP levels in breast cancer cells. This result is associated with increased mitochondrial respiration evaluated by Seahorse analyzer, supporting the concept that Lep-EVs can modulate MCF-7 breast cancer cell oxidative metabolism. Moreover, taking into account the relevance of tumor immune cell crosstalk in the tumor microenvironment (TME), we analyzed the impact of these vesicles on macrophage polarization, the most abundant immune component in the breast TME. We found that tumor-derived Lep-EVs sustain the polarization of M0 macrophages, derived from the human THP-1 monocytic cells, into M2-like tumor-associated macrophages, in terms of metabolic features, phagocytic activity, and increased expression of CD206-positive population. Overall, our results indicate that leptin by inducing the release of EV-enriched in mitochondrial proteins may control the metabolism of MCF-7 breast cancer cells as well as that of macrophages. Characterization of tumor-derived EV protein cargo in an obesity-associated milieu, such as in the presence of elevated leptin levels, might allow identifying unique features and specific metabolic mechanisms useful to develop novel therapeutic approaches for treatment of breast cancer, especially in obese patients.

Extracellular vesicles: A new diagnostic biomarker and targeted drug in osteosarcoma

Osteosarcoma (OS) is a primary bone cancer that is highly prevalent among adolescents and adults below the age of 20 years. The prognostic outcome of metastatic OS or relapse is extremely poor; thus, developing new diagnostic and therapeutic strategies for treating OS is necessary. Extracellular vesicles (EVs) ranging from 30–150 nm in diameter are commonly produced in different cells and are found in various types of body fluids. EVs are rich in biologically active components like proteins, lipids, and nucleic acids. They also strongly affect pathophysiological processes by modulating the intercellular signaling pathways and the exchange of biomolecules. Many studies have found that EVs influence the occurrence, development, and metastasis of osteosarcoma. The regulation of inflammatory communication pathways by EVs affects OS and other bone-related pathological conditions, such as osteoarthritis and rheumatoid arthritis. In this study, we reviewed the latest findings related to diagnosis, prognosis prediction, and the development of treatment strategies for OS from the perspective of EVs.

Exosomal microRNAs synergistically trigger stromal fibroblasts in breast cancer

Triple-negative breast cancer (TNBC) is the most aggressive breast cancer subtype. TNBC progression is sustained by recruitment of a strong tumor microenvironment (TME) mainly composed of cancer-associated fibroblasts (CAFs) able to endorse tumor hallmarks. Increasing evidences demonstrate that exosomes mediate the crosstalk between cancer cells and the TME. We examined TNBC-derived exosomes and their microRNA (miRNA) cargo in activation of normal fibroblasts (NFs) toward CAFs. We demonstrated that TNBC cell-derived exosomes increased NF collagen contraction and migration alongside CAF molecular markers. Exosome-activated fibroblasts promoted the invasion potential of normal breast epithelial cells, as assessed by an organotypic co-culture assay that resembled the in vivo context. We also investigated TNBC cell-derived exosome cargo in activating NFs to CAFs by performing small RNA sequencing. We found that the synergistic action of miR-185-5p, miR-652-5p, and miR-1246 boosted fibroblast migration and contraction, promoting specific CAF subspecialization toward a pro-migratory functional state. These data highlight the role of breast cancer cells in re-education of the TME and their contribution to tumor evolution.

Vesicular Ganglioside GM1 From Breast Tumor Cells Stimulated Epithelial-to-Mesenchymal Transition of Recipient MCF-10A Cells

Small extracellular vesicles (sEVs) are a type of membrane structure secreted by cells, which are involved in physiological and pathological processes by participating in intercellular communication. Glycosphingolipids (GSLs) are enriched in sEV and can be delivered to recipient cells. In this study, we found that overexpression of B3GALT4, the glycosyltransferase responsible for ganglioside GM1 synthesis, can induce the epithelial-mesenchymal transition (EMT) process in MCF-10A cells. Moreover, GM1 was verified to be presented on sEV from breast cancer cells. Overexpression of B3GALT4 resulted in elevated vesicular GM1 levels and increased sEV secretion in breast cancer cells. Proteomic analysis revealed that eleven sEV secretion-related proteins were differentially expressed, which might contribute to the altered sEV secretion. Of the identified proteins, 15 oncogenic differentially expressed proteins were documented to be presented in sEV. With the treatment of GM1-enriched sEV from breast cancer cells, the EMT process was induced in recipient non-tumorigenic epithelial MCF-10A cells. Our findings demonstrated that GM1-enriched sEVs derived from breast cancer cells induced the EMT process of recipient cells, which might provide essential information on the biological function of vesicular GM1.

Prognostic Biomarker NUMB Is Inhibited by Breast Cancer Cell Exosomes to Promote Breast Cancer Progression

Objective

To clarify the regulation of breast cancer cell-derived exosomes on breast cancer and the expression of the NUMB endocytic adaptor protein (NUMB) protein.

Methods

The exosomes of breast cancer cell line MDA-MB-231 were isolated. The exosomes were subsequently labeled with PKH67 and added to breast cancer MDA-MB-231 cells cultured in vitro. Transwell and clone formation assays were performed to detect cell migration, invasion, and clone formation. Meanwhile, Western blot and qPCR were conducted to determine the regulation of NUMB expression by exosomes in breast cancer cells. Furthermore, NUMB overexpressed lentivirus was supplemented to validate the recovery.

Results

The number of migrating and invasive breast cancer cells in the exosome-treated group was significantly increased compared with the control group. Moreover, the number of breast cancer cell clones in the exosome-treated group was increased than in the control group. However, the NUMB expression in breast cancer cells treated with exosomes revealed a substantial decrease, indicating that the exosomes of breast cancer cells could inhibit NUMB expression. NUMB overexpressed lentivirus supplementation markedly suppressed cell migration, invasion, and proliferation of breast cancer cells compared with exosome group.

Conclusion

Taken together, the exosomes of breast cancer cells could inhibit the expression of NUMB and promote the migration, invasion, and cell clone formation of breast cancer cells.

Extracellular Vesicles as Mediators of Therapy Resistance in the Breast Cancer Microenvironment

Resistance to various therapies, including novel immunotherapies, poses a major challenge in the management of breast cancer and is the leading cause of treatment failure. Bidirectional communication between breast cancer cells and the tumour microenvironment is now known to be an important contributor to therapy resistance. Several studies have demonstrated that crosstalk with the tumour microenvironment through extracellular vesicles is an important mechanism employed by cancer cells that leads to drug resistance via changes in protein, lipid and nucleic acid cargoes. Moreover, the cargo content enables extracellular vesicles to be used as effective biomarkers for predicting response to treatments and as potential therapeutic targets. This review summarises the literature to date regarding the role of extracellular vesicles in promoting therapy resistance in breast cancer through communication with the tumour microenvironment.

Breast Cancer Tumor Microenvironment and Molecular Aberrations Hijack Tumoricidal Immunity

Simple Summary

Immune therapy is designed to stimulate tumoricidal effects in a variety of solid tumors including breast carcinomas. However, the emergence of resistant clones leads to treatment failure. Understanding the molecular, cellular, and microenvironmental aberrations is crucial to uncovering underlying mechanisms and developing advanced strategies for preventing or combating these resistant malignancies. This review will summarize research findings revealing various mechanisms employed to hijack innate and adaptive immune surveillance mechanisms, develop hypoxic and tumor promoting metabolism, and foster an immune tolerance microenvironment. In addition, it will highlight potential targets for therapeutic approaches.

Abstract

Breast cancer is the most common malignancy among females in western countries, where women have an overall lifetime risk of >10% for developing invasive breast carcinomas. It is not a single disease but is composed of distinct subtypes associated with different clinical outcomes and is highly heterogeneous in both the molecular and clinical aspects. Although tumor initiation is largely driven by acquired genetic alterations, recent data suggest microenvironment-mediated immune evasion may play an important role in neoplastic progression. Beyond surgical resection, radiation, and chemotherapy, additional therapeutic options include hormonal deactivation, targeted-signaling pathway treatment, DNA repair inhibition, and aberrant epigenetic reversion. Yet, the fatality rate of metastatic breast cancer remains unacceptably high, largely due to treatment resistance and metastases to brain, lung, or bone marrow where tumor bed penetration of therapeutic agents is limited. Recent studies indicate the development of immune-oncological therapy could potentially eradicate this devastating malignancy. Evidence suggests tumors express immunogenic neoantigens but the immunity towards these antigens is frequently muted. Established tumors exhibit immunological tolerance. This tolerance reflects a process of immune suppression elicited by the tumor, and it represents a critical obstacle towards successful antitumor immunotherapy. In general, immune evasive mechanisms adapted by breast cancer encompasses down-regulation of antigen presentations or recognition, lack of immune effector cells, obstruction of anti-tumor immune cell maturation, accumulation of immunosuppressive cells, production of inhibitory cytokines, chemokines or ligands/receptors, and up-regulation of immune checkpoint modulators. Together with altered metabolism and hypoxic conditions, they constitute a permissive tumor microenvironment. This article intends to discern representative incidents and to provide potential innovative therapeutic regimens to reinstate tumoricidal immunity.

The emerging roles of exosomal long non-coding RNAs in bladder cancer

Extracellular vesicles (EVs), especially exosomes, have been reported to play essential roles as extracellular messengers by transporting goods in various diseases, while their potential roles in bladder cancer (BC) still remain to be further studied. BC exhibits a high degree of chemoresistance and metastatic ability, which may be affected by cancer‐derived exosomes that carry proteins, lipids and RNA. To date, the most studied exosomal molecular cargo is long non‐coding RNA (lncRNA). Although there is increasing interest in its role and function, there is relatively little knowledge about it compared with other RNA transcripts. Nevertheless, in the past ten years, we have witnessed increasing interest in the role and function of lncRNA. For example, lncRNAs have been studied as potential biomarkers for the diagnosis of BC. They may play a role as a therapeutic target in precision medicine, but they may also be directly involved in the characteristics of tumour progression, such as metastasis, epithelial‐mesenchymal transition and drug resistance. Cancer cells are on chemotherapy acting. The function of lncRNA in various cancer exosomes has not yet been determined. In this review, we summarize the current studies about the prominent roles of exosomal lncRNAs in genome integrity, BC progression and carcinogenic features.

Exosome-based delivery nanoplatforms: Next-generation theranostic platforms for breast cancer

Breast cancer is the most frequent type of malignancy, and the leading cause of cancer-related death in women across the globe. Exosomes are naturally derived 50-150 nm nanovesicles with a...

Extracellular vesicle-mediated transport: Reprogramming a tumor microenvironment conducive with breast cancer progression and metastasis

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Extracellular vesicles’ (EVs) role in breast tumor microenvironment and pre-metastatic niche development.

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Breast cancer EV-mediated transmission of pro-metastatic and drug-resistant phenotypes.

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Precision medicine with EVs as biomarkers and delivery vehicles for drug and anticancer genetic material.

Breast cancer metastatic progression to critical secondary sites is the second leading cause of cancer-related mortality in women. While existing therapies are highly effective in combating primary tumors, metastatic disease is generally deemed incurable with a median survival of only 2, 3 years. Extensive efforts have focused on identifying metastatic contributory targets for therapeutic antagonism and prevention to improve patient survivability. Excessive breast cancer release of extracellular vesicles (EVs), whose contents stimulate a metastatic phenotype, represents a promising target. Complex breast cancer intercellular communication networks are based on EV transport and transference of molecular information is in bulk resulting in complete reprogramming events within recipient cells. Other breast cancer cells can acquire aggressive phenotypes, endothelial cells can be induced to undergo tubule formation, and immune cells can be neutralized. Recent advancements continue to implicate the critical role EVs play in cultivating a tumor microenvironment tailored to cancer proliferation, metastasis, immune evasion, and conference of drug resistance. This literature review serves to frame the role of EV transport in breast cancer progression and metastasis. The following five sections will be addressed: (1) Intercellular communication in developing a tumor microenvironment & pre-metastatic niche. (2) Induction of the epithelial-to-mesenchymal transition (EMT). (3). Immune suppression & evasion. (4) Transmission of drug resistance mechanisms. (5) Precision medicine: clinical applications of EVs.

Exosomes: A Forthcoming Era of Breast Cancer Therapeutics

Despite the recent advancements in therapeutics and personalized medicine, breast cancer remains one of the most lethal cancers among women. The prognostic and diagnostic aids mainly include assessment of tumor tissues with conventional methods towards better therapeutic strategies. However, current era of gene-based research may influence the treatment outcome particularly as an adjunct to diagnostics by exploring the role of non-invasive liquid biopsies or circulating markers. The characterization of tumor milieu for physiological fluids has been central to identifying the role of exosomes or small extracellular vesicles (sEVs). These exosomes provide necessary communication between tumor cells in the tumor microenvironment (TME). The manipulation of exosomes in TME may provide promising diagnostic/therapeutic strategies, particularly in triple-negative breast cancer patients. This review has described and highlighted the role of exosomes in breast carcinogenesis and how they could be used or targeted by recent immunotherapeutics to achieve promising intervention strategies.

Adipocyte-derived extracellular vesicles promote breast cancer cell malignancy through HIF-1α activity

Extracellular vesicles (EVs) are emerging key protagonists in intercellular communication between adipocytes and breast cancer (BC) cells. Here, we described a new mechanism by which EVs released by mature adipocytes promoted breast cancer cell malignancy "in vitro" and "in vivo". We found that adipocyte-derived EVs enhanced growth, motility and invasion, stem cell-like properties, as well as specific traits of epithelial-to-mesenchymal transition in both estrogen receptor positive and triple negative BC cells. Of note, adipocyte-derived EVs aid breast tumor cells in lung metastatic colonization after tail-vein injection in mice. These EV-mediated effects occur via the induction of HIF-1α activity, since they were abrogated by the use of the HIF-1α inhibitor KC7F2 or in cells silenced for HIF-1α expression. Moreover, using an "ex vivo" model of obese adipocytes we found that the depletion of EVs counteracted the ability of obese adipocytes to sustain pro-invasive phenotype in BC cells. Interestingly, EVs released by undifferentiated adipocytes failed to induce aggressiveness and HIF-1α expression. These findings shed new light on the role of adipocyte-derived EVs in breast cancer progression, suggesting the possibility to target HIF-1α activity to block the harmful adipocyte-tumor cell dialogue, especially in obese settings.

Glypican-1 Overexpression in Different Types of Breast Cancers

Purpose

Treatment of metastatic breast cancer patients is challenging and remains a major underlying cause of female mortality. Understanding molecular alterations in tumor development is critical to identify novel biomarkers and targets for cancer diagnosis and therapy. One of the aberrant cancer expressions gaining recent research interest is glypican-1. Several studies reported strong glypican-1 expression in various types of human cancers. However, none of these investigated glypican-1 expression in a large cohort of breast cancer histopathological subtypes.

Patients and Methods

Immunohistochemistry was used to assess glypican-1 expression in 220 breast cancer patients and its relation to demographic and clinical features, as well as important prognostic immunohistochemical markers for breast cancer.

Results

Intense glypican-1 expression was recognized in all breast cancer histopathological subtypes. Normal, healthy breast tissue displayed a heterogeneous low expression (20%). Importantly, a strong differential in glypican-1 expression was determined between normal and malignant breast tissues. Moreover, there was a significantly high rate of glypican-1 expression in advanced grades of breast cancer patients and larger tumor sizes. Unfortunately, the glypican-1 expression demonstrated no obvious relationship with the expression of various biomarkers in breast cancer.

Conclusion

This study may establish glypican-1 as a promising new therapeutic target for the development of therapy in breast cancer.

EMT Participates in the Regulation of Exosomes Secretion and Function in Esophageal Cancer Cells

Epithelial-mesenchymal transition (EMT) is a key step in tumor invasion and distant metastasis. Abundant evidence has documented that exosomes can mediate EMT of tumor cells and endow them with the ability of invasion and migration. However, there are few studies focusing on whether EMT can reverse the secretion of exosomes. In this study, 2 esophageal cancer cells (FLO-1 and SK-GT-4) were selected to compare the migration ability and EMT activation, and to further analyze the secretion ability of exosomes of the 2 cell lines. According to the results, inhibited activation of EMT in FLO-1 cells with relatively high migration ability could effectively reduce the secretion of exosomes. Besides, in SK-GT-4 cells, EMT activation induced by TGF-β could promote the secretion of exosomes. FLO-1 cell derived exosomes exhibited a paracrine effect of promoting the migration of SK-GT-4 cells, and the use of EMT inhibitors could weaken this ability. Furthermore, inhibition of EMT could change the relative content of some miRNAs in exosomes, with a particularly significant downregulation in the expression of miR-196-5p, miR-21-5p and miR-194-5p. Significantly, artificial transfection of the 3 miRNAs into exosomes by electroporation resulted in the recovery of migration-promoting effect of exosomes. Subsequent experiments further revealed that the effect of EMT on these miRNAs could be explained by the intracellular transcription level or the specific sorting mechanism of exosomes. To sum up, our study undoubtedly reveals that EMT has a regulatory effect on exosomes in the quantity and contents in esophageal cancer cells. Significantly, findings in our study provide experimental evidence for the interaction of EMT with the secretion and sorting pathway of exosomes, and also give a new direction for the further study of tumor metastasis.

Tumor-derived exosomal components: the multifaceted roles and mechanisms in breast cancer metastasis

Breast cancer (BC) is the most frequently invasive malignancy and the leading cause of tumor-related mortality among women worldwide. Cancer metastasis is a complex, multistage process, which eventually causes tumor cells to colonize and grow at the metastatic site. Distant organ metastases are the major obstacles to the management of advanced BC patients. Notably, exosomes are defined as specialized membrane-enclosed extracellular vesicles with specific biomarkers, which are found in a wide variety of body fluids. Recent studies have demonstrated that exosomes are essential mediators in shaping the tumor microenvironment and BC metastasis. The transferred tumor-derived exosomes modify the capability of invasive behavior and organ-specific metastasis in recipient cells. BC exosomal components, mainly including noncoding RNAs (ncRNAs), proteins, lipids, are the most investigated components in BC metastasis. In this review, we have emphasized the multifaceted roles and mechanisms of tumor-derived exosomes in BC metastasis based on these important components. The underlying mechanisms mainly include the invasion behavior change, tumor vascularization, the disruption of the vascular barrier, and the colonization of the targeted organ. Understanding the significance of tumor-derived exosomal components in BC metastasis is critical for yielding novel routes of BC intervention.

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.

The Emerging Role of Extracellular Vesicles in Endocrine Resistant Breast Cancer

Simple Summary

Two-thirds of breast cancer patients present an estrogen receptor–positive tumor at diagnosis, and the main treatment options for these patients are endocrine therapies such as aromatase inhibitors, selective modulators of estrogen receptor activity or selective estrogen receptor down-regulators. Although endocrine therapies have high efficacy in early-stage breast cancers, the failure of the therapeutic response to these hormonal treatments remains the major clinical challenge. Recently, extracellular vesicles (EVs) have emerged as a novel mechanism of drug resistance. Indeed, EVs isolated from tumor and stromal cells act as key messengers in intercellular communications able to propagate traits of resistance and/or educate the microenvironment to sustain a breast cancer resistant phenotype. Understanding the EV-mediated molecular mechanisms involved in hormonal resistance can provide the rationale for novel and effective treatment modalities and allow for the identification of potential biomarkers to monitor therapy response in ER-positive breast cancer patients.

Abstract

Breast cancer is the most common solid malignancy diagnosed in females worldwide, and approximately 70% of these tumors express estrogen receptor α (ERα), the main biomarker of endocrine therapy. Unfortunately, despite the use of long-term anti-hormone adjuvant treatment, which has significantly reduced patient mortality, resistance to the endocrine treatments often develops, leading to disease recurrence and limiting clinical benefits. Emerging evidence indicates that extracellular vesicles (EVs), nanosized particles that are released by all cell types and responsible for local and systemic intercellular communications, might represent a newly identified mechanism underlying endocrine resistance. Unraveling the role of EVs, released by transformed cells during the tumor evolution under endocrine therapy, is still an open question in the cancer research area and the molecular mechanisms involved should be better defined to discover alternative therapeutic approaches to overcome resistance. In this review, we will provide an overview of recent findings on the involvement of EVs in sustaining hormonal resistance in breast cancer and discuss opportunities for their potential use as biomarkers to monitor the therapeutic response and disease progression.

Natural and Synthetic PPARγ Ligands in Tumor Microenvironment: A New Potential Strategy against Breast Cancer

Multiple lines of evidence indicate that activation of the peroxisome proliferator-activated receptor γ (PPARγ) by natural or synthetic ligands exerts tumor suppressive effects in different types of cancer, including breast carcinoma. Over the past decades a new picture of breast cancer as a complex disease consisting of neoplastic epithelial cells and surrounding stroma named the tumor microenvironment (TME) has emerged. Indeed, TME is now recognized as a pivotal element for breast cancer development and progression. Novel strategies targeting both epithelial and stromal components are under development or undergoing clinical trials. In this context, the aim of the present review is to summarize PPARγ activity in breast TME focusing on the role of this receptor on both epithelial/stromal cells and extracellular matrix components of the breast cancer microenvironment. The information provided from the in vitro and in vivo research indicates PPARγ ligands as potential agents with regards to the battle against breast cancer.

How to Predict Metastasis in Luminal Breast Cancer? Current Solutions and Future Prospects

Breast cancer metastasis is the main cause of breast cancer mortality. Luminal breast cancer represents the majority of breast cancer cases and, despite relatively good prognosis, its heterogeneity creates problems with a proper stratification of patients and correct identification of the group with a high risk of metastatic relapse. Current prognostic tools are based on the analysis of the primary tumor and, despite their undisputed power of prediction, they might be insufficient to foresee the relapse in an accurate and precise manner, especially if the relapse occurs after a long period of dormancy, which is very common in luminal breast cancer. New approaches tend to rely on body fluid analyses, which have the advantage of being non-invasive and versatile and may be repeated and used for monitoring the disease in the long run. In this review we describe the current, newly-developed, and only-just-discovered methods which are or may become useful in the assessment of the probability of the relapse.

Antagonistic Functions of Connexin 43 during the Development of Primary or Secondary Bone Tumors

Despite research and clinical advances during recent decades, bone cancers remain a leading cause of death worldwide. There is a low survival rate for patients with primary bone tumors such as osteosarcoma and Ewing’s sarcoma or secondary bone tumors such as bone metastases from prostate carcinoma. Gap junctions are specialized plasma membrane structures consisting of transmembrane channels that directly link the cytoplasm of adjacent cells, thereby enabling the direct exchange of small signaling molecules between cells. Discoveries of human genetic disorders due to genetic mutations in gap junction proteins (connexins) and experimental data using connexin knockout mice have provided significant evidence that gap-junctional intercellular communication (Gj) is crucial for tissue function. Thus, the dysfunction of Gj may be responsible for the development of some diseases. Gj is thus a main mechanism for tumor cells to communicate with other tumor cells and their surrounding microenvironment to survive and proliferate. If it is well accepted that a low level of connexin expression favors cancer cell proliferation and therefore primary tumor development, more evidence is suggesting that a high level of connexin expression stimulates various cellular process such as intravasation, extravasation, or migration of metastatic cells. If so, connexin expression would facilitate secondary tumor dissemination. This paper discusses evidence that suggests that connexin 43 plays an antagonistic role in the development of primary bone tumors as a tumor suppressor and secondary bone tumors as a tumor promoter.