Tumor-derived extracellular vesicles in breast cancer: From bench to bedside

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.

Engineered Extracellular Vesicles Expressing Siglec-10 Camouflaged AIE Photosensitizer to Reprogram Macrophages to Active M1 Phenotype and Present Tumor-Associated Antigens for Photodynamic Immunotherapy

Cancer immunotherapy has attracted considerable attention due to its advantages of persistence, targeting, and ability to kill tumor cells. However, the efficacy of tumor immunotherapy in practical applications is limited by tumor heterogeneity and complex tumor immunosuppressive microenvironments in which abundant of M2 macrophages and immune checkpoints (ICs) are present. Herein, two type-I aggregation-induced emission (AIE)-active photosensitizers with various reactive oxygen species (ROS)-generating efficiencies are designed and synthesized. Engineered extracellular vesicles (EVs) that express ICs Siglec-10 are first obtained from 4T1 tumor cells. The engineered EVs are then fused with the AIE photosensitizer-loaded lipidic nanosystem to form SEx@Fc-NPs. The ROS generated by the inner type-I AIE photosensitizer of the SEx@Fc-NPs through photodynamic therapy (PDT) can convert M2 macrophages into M1 macrophages to improve tumor immunosuppressive microenvironment. The outer EV-antigens that carry 4T1 tumor-associated antigens directly stimulate dendritic cells maturation to activate different types of tumor-specific T cells in overcoming tumor heterogeneity. In addition, blocking Siglec-10 reversed macrophage exhaustion for enhanced antitumor ability. This study presents that a combination of PDT, immune checkpoints, and EV-antigens can greatly improve the efficiency of tumor immunotherapy and is expected to serve as an emerging strategy to improve tumor immunosuppressive microenvironment and overcome immune escape.

Lysine lactylation (Kla) might be a novel therapeutic target for breast cancer

BACKGROUND

Histone lysine lactylation (Kla) is a newly identified histone modification, which plays a crucial role in cancer progression. Hence, we determined the prognostic value of Kla in breast cancer (BC).

METHODS

We obtained RNA expression profiles of BC from The Cancer Genome Atlas (TCGA), following screening out Kla-specific genes. Furthermore, we determined the prognostic value of Kla by constructing a cox model based on Kla-specific genes. Subsequently, we identified expression of lactate accumulation-related genes and prognostic Kla-specific genes through Human Protein Atlas (HPA), and further performed a correlation analysis based on their expression. Meanwhile, we explored the effects of Kla on BC tumor microenvironment (TME), drug therapy and immunotherapy. Moreover, we predicted the pathways influenced by Kla via gene set enrichment analysis (GSEA).

RESULTS

A total of 1073 BC samples and 112 normal controls were obtained from TCGA, and 23 tumor samples were removed owing to inadequate clinical information. We identified 257 differentially expressed Kla-specific genes (DEKlaGs) in BC. A cox model involved with CCR7, IGFBP6, NDUFAF6, OVOL1 and SDC1 was established, and risk score could be visualized as an independent biomarker for BC. Meanwhile, Kla was remarkably associated with BC immune microenvironment, drug therapy and immunotherapy. Kla was identified to be related to activation of various BC-related KEGG pathways.

CONCLUSION

In conclusion, Kla contributes to drug resistance and undesirable immune responses, and plays a crucial role in BC prognosis, suggesting that Kla was expected to be a new therapeutic target for BC.

Decoding Hidden Messengers: Proteomic Profiling of Exosomes in Mammary Cancer Research

Cancer is a complex and heterogeneous disease, influenced by various factors that affect its progression and response to treatment. Although a histopathological diagnosis is crucial for identifying and classifying cancer, it may not accurately predict the disease's development and evolution in all cases. To address this limitation, liquid biopsy has emerged as a valuable tool, enabling a more precise and non-invasive analysis of cancer. Liquid biopsy can detect tumor DNA fragments, circulating tumor cells, and exosomes released by cancer cells into the bloodstream. Exosomes attracted significant attention in cancer research because of their specific protein composition, which can provide valuable insights into the disease. The protein profile of exosomes often differs from that of normal cells, reflecting the unique molecular characteristics of cancer. Analyzing these proteins can help identify cancer-associated markers that play important roles in tumor progression, invasion, and metastasis. Ongoing research and clinical validation are essential to advance and effectively utilize protein biomarkers in cancer. Nevertheless, their potential to improve diagnosis and treatment is highly promising. This review discusses several exosome proteins of interest in breast cancer, particularly focusing on studies conducted in mammary tissue and cell lines in humans and experimental animals. Unfortunately, studies conducted in canine species are scarce. This emphasis sheds light on the limited research available in this field. In addition, we present a curated selection of studies that explored exosomal proteins as potential biomarkers, aiming to achieve benefits in breast cancer diagnosis, prognosis, monitoring, and treatment.

Extracellular Vesicles in Breast Cancer: From Biology and Function to Clinical Diagnosis and Therapeutic Management

Breast cancer (BC) is the first worldwide most frequent cancer in both sexes and the most commonly diagnosed in females. Although BC mortality has been thoroughly declining over the past decades, there are still considerable differences between women diagnosed with early BC and when metastatic BC is diagnosed. BC treatment choice is widely dependent on precise histological and molecular characterization. However, recurrence or distant metastasis still occurs even with the most recent efficient therapies. Thus, a better understanding of the different factors underlying tumor escape is mainly mandatory. Among the leading candidates is the continuous interplay between tumor cells and their microenvironment, where extracellular vesicles play a significant role. Among extracellular vesicles, smaller ones, also called exosomes, can carry biomolecules, such as lipids, proteins, and nucleic acids, and generate signal transmission through an intercellular transfer of their content. This mechanism allows tumor cells to recruit and modify the adjacent and systemic microenvironment to support further invasion and dissemination. By reciprocity, stromal cells can also use exosomes to profoundly modify tumor cell behavior. This review intends to cover the most recent literature on the role of extracellular vesicle production in normal and cancerous breast tissues. Specific attention is paid to the use of extracellular vesicles for early BC diagnosis, follow-up, and prognosis because exosomes are actually under the spotlight of researchers as a high-potential source of liquid biopsies. Extracellular vesicles in BC treatment as new targets for therapy or efficient nanovectors to drive drug delivery are also summarized.

Relationship between Tumor Budding and Partial Epithelial-Mesenchymal Transition in Head and Neck Cancer

Tumor budding (TB), a microscopic finding in the stroma ahead of the invasive fronts of tumors, has been well investigated and reported as a prognostic marker in head and neck squamous cell carcinoma (HNSCC). Epithelial-mesenchymal transition (EMT) is a crucial step in tumor progression and metastasis, and its status cannot be distinguished from TB. The current understanding of partial EMT (p-EMT), the so-called halfway step of EMT, focuses on the tumor microenvironment (TME). Although this evidence has been investigated, the clinicopathological and biological relationship between TB and p-EMT remains debatable. At the invasion front, previous research suggested that cancer-associated fibroblasts (CAFs) are important for tumor progression, metastasis, p-EMT, and TB formation in the TME. Although there is biological evidence of TB drivers, no report has focused on their organized functional relationships. Understanding the mechanism of TB onset and the relationship between p-EMTs may facilitate the development of novel diagnostic and prognostic methods, and targeted therapies for the prevention of metastasis in epithelial cancer. Thus far, major pieces of evidence have been established from colorectal cancer (CRC), due to a large number of patients with the disease. Herein, we review the current understanding of p-EMT and TME dynamics and discuss the relationship between TB development and p-EMT, focusing on CAFs, hypoxia, tumor-associated macrophages, laminin-integrin crosstalk, membrane stiffness, enzymes, and viral infections in cancers, and clarify the gap of evidence between HNSCC and CRC.

Exosome-Based Smart Drug Delivery Tool for Cancer Theranostics

Exosomes are the phospholipid-membrane-bound subpopulation of extracellular vesicles derived from the plasma membrane. The main activity of exosomes is cellular communication. In cancer, exosomes play an important rolefrom two distinct perspectives, one related to carcinogenesis and the other as theragnostic and drug delivery tools. The outer phospholipid membrane of Exosome improves drug targeting efficiency. . Some of the vital features of exosomes such as biocompatibility, low toxicity, and low immunogenicity make it a more exciting drug delivery system. Exosome-based drug delivery is a new innovative approach to cancer treatment. Exosome-associated biomarker analysis heralded a new era of cancer diagnostics in a more specific way. This Review focuses on exosome biogenesis, sources, isolation, interrelationship with cancer and exosome-related cancer biomarkers, drug loading methods, exosome-based biomolecule delivery, advances and limitations of exosome-based drug delivery, and exosome-based drug delivery in clinical settings studies. The exosome-based understanding of cancer will change the diagnostic and therapeutic approach in the future.

Bone Marrow Mesenchymal Stem Cells Restrain the Migration and Invasion of Breast Cancer Cells by Up-Regulating miR-2158 and Inactivating RAI2/NLRP3 Pathway

Exosomes are the key mediator for intercellular communication and participate in malignancies. Short non-coding RNAs derived from BMSCs-originated exosomes (BMSCs-exosomes) can be employed as biomolecules for tumor treatment. Here to we aim to dissect the function of microRNA-2158 from BMSCs-exosomes in breast malignant disease. Breast malignant cells received a separated transfection of miR-2158-mimics and miR-2158-inhibitor, and also treated with BMSCoriginated exosomes followed by analysis of cell viability by MTT method, cell invading and migrating capabilities via Transwell assays and protein levels of EMT-related and RAI2/NLRP3-related proteins by Western-blot. Breast cancer cells exhibited a significantly enhanced miR-2158 expression after transfection with miR-2158-mimics or treatment with BMSC-EXO, while it was reduced by miR-2158-inhibitor. As the miR-2158 was up-regulated, a significant impediment of proliferation and migration was denoted, along with a down-regulation of RAI2/NLRP3 signal transduction pathway and a retarded EMT process. Furthermore, cell proliferating and migrating capabilities were strengthened by miR-2158-inhibitor, together with an enhanced RAI2/NLRP3 signal and a strengthened EMT process. In conclusion, miR-2158 retarded the in vitro proliferating and migrating activities of breast malignant cells, leading to the inactivation of RAI2/NLRP3 signal transduction pathway, thereby exerting its tumor-suppressing function.

Tumor-Derived Extracellular Vesicles as Complementary Prognostic Factors to Circulating Tumor Cells in Metastatic Breast Cancer

PURPOSE

Circulating tumor cells (CTCs) are strongly prognostic for overall survival (OS) in metastatic breast cancer although additional prognostic biomarkers are needed. We evaluated the complementary prognostic value of tumor-derived extracellular vesicles (tdEVs) next to CTCs.

METHODS

We applied the open-source ACCEPT software to archived CellSearch images from the prospective clinical trial SWOG0500 to enumerate CTCs and tumor-derived extracellular vesicles (tdEVs) before and after one cycle of chemotherapy.

RESULTS

CTCs enumerated by ACCEPT were strongly correlated with classical ocular enumeration (correlation r = 0.98). OS was worse with elevated tdEVs (median OS for high/medium/low groups: 17.1 v 29.0 v 43.3 months; P < .0001). In patients with longer OS by CTC counts (< 5 CTC/7.5 mL blood), elevated tdEV levels were independently associated with poorer OS (multivariable analysis P < .001). OS was also longer for patients with low tdEVs after one cycle of chemotherapy (median OS for high/medium/low group: 10.8 v 17.8 v 26.7; P < .0001).

CONCLUSION

This study highlights the complementary prognostic significance of tdEVs in metastatic breast cancer before and after one cycle of chemotherapy.

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

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

DCXR promotes cell proliferation by promoting the activity of aerobic glycolysis in breast cancer

The function of human dicarbonyl/L‑xylulose reductase (DCXR) in the pathophysiology of breast cancer is yet to be elucidated. The present study aimed to investigate the function of DCXR in glycolysis and the cell cycle of breast cancer cells with respect to cell proliferation. Differential expressed DCXR was identified in The Cancer Genome Atlas (TCGA) database and verified in clinical breast cancer tissue. DCXR silencing and overexpression were induced by RNA interference and lentiviral vectors, respectively. Cell cycle progression, proliferation and glycolytic activity of breast cancer cells were detected by flow cytometry, Cell Counting Kit‑8 assay and chemical methods, respectively. Tumorigenicity was detected using nude mice xenograft models. The expression of DCXR was increased in TCGA breast cancer database and the function of DCXR was enriched in 'glycolysis' and 'cell cycle'. Further analysis using clinical breast cancer samples confirmed upregulation of DCXR. The silencing of DCXR suppressed proliferation and cell cycle progression of breast cancer cells and significantly decreased the capacity for glycolysis, thereby demonstrating the effect of DCXR on the function of breast cancer cells. Similar conclusions were obtained in DCXR overexpressing cells; notably, DCXR overexpression promoted proliferation, cell cycle progression at S phase and glycolysis. 2‑Deoxy‑D‑glucose inhibited the effect of DCXR on the proliferation and cell cycle progression of breast cancer cells. The present study revealed that DCXR regulated breast cancer cell cycle progression and proliferation by increasing glycolysis activity and thus may serve as an oncogene for breast cancer.

The impacts of exosomes on bone metastatic progression and their potential clinical utility

Bone is one of the most common sites of cancer metastasis. Once cancer metastasizes to the bone, the mortality rate of cancer patients dramatically increases. Although the exact mechanisms for this observation remain elusive, recent studies have revealed that the complex crosstalk between bone marrow microenvironment and bone metastatic cancer cells is responsible for the induction of treatment resistance. Consequently, bone metastasis is currently considered incurable. Bone metastasis not only impairs the patients' survival, but also negatively affects their quality of life by causing painful complications. It has recently been implicated the regulatory role of exosomes in cancer development and/or progression as a delivery biomaterial between cancer cells and tumor microenvironment. However, little is known as to how exosomes contribute to the progression of bone metastasis by impaction on the crosstalk between bone metastatic cancer cells and bone marrow microenvironment. Here, we highlighted the emerging roles of cancer-derived exosomes in (i) the process of dissemination and bone colonization of bone metastatic cancer cells, (ii) the enhancement of crosstalk between bone marrow microenvironment and bone metastatic cancer cells, (iii) the development of its resultant painful complications, and (iv) the clinical applications of exosomes in the bone metastatic setting.

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Cancer-derived exosomes facilitate cancer dissemination and colonization to bone.

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Cancer-derived exosomes are crucial for controlling bone metastatic phenotype.

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Cancer-derived exosomes prime bone marrow microenvironment for further metastasis.

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Cancer-derived exosomes are involved in development of cancer-induced bone pain.

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Exosomes can be used as therapies and/or diagnostic tools for bone metastasis.

Salivary non-apoptotic tumoral microvesicles: A potential progressive marker in oral cancer patients

Tumour cell-secreted microvesicles (MVs) contribute immensely to tumour progression. However, the role of tumoral salivary MVs in oral squamous cell carcinoma (OSCC) remains unclear. Herein, we elucidated the role of non-apoptotic salivary tumoral MVs in OSCC development, especially relating to the migration ability. We purified and compared non-apoptotic salivary tumoral MVs from 63 OSCC patients and orthotopic OSCC mice model. Next, we compared the protein difference between apoptotic and non-apoptotic MVs by Western blot, proteomics and flow cytometry from saliva and CAL27 cells. Finally, we collected the non-apoptotic MVs and co-cultured with normal oral epithelial cells, the migration ability was examined by wound healing assay and Western blot assay. Our results indicated that the levels of non-apoptotic tumoral S-MVs were significantly higher in OSCC patients with T3 to T4 stages than in patients with T1 to T2 stages or healthy donors. In OSCC mice model, we found elevations of non-apoptotic tumoral MVs associated with tumoral volume. EGFR overexpression increased the generation of non-apoptotic tumoral MVs which could significantly promote normal epithelial cell migration. In conclusion, elevated levels of non-apoptotic tumoral S-MVs are associated with clinicopathologic features of OSCC patients, implying that non-apoptotic tumoral S-MVs are a potential progressive marker of OSCC.

Investigating the consistency of extracellular vesicle production from breast cancer subtypes using CELLine adherent bioreactors

Extracellular vesicle (EV) research has grown rapidly in recent years, largely due to the potential use of EVs as liquid biopsy biomarkers or therapeutics. However, in-depth characterisation and validation of EVs produced using conventional in vitro cultures can be challenging due to the large area of cell monolayers and volumes of culture media required. To overcome this obstacle, multiple bioreactor designs have been tested for EV production with varying success, but the consistency of EVs produced over time in these systems has not been reported previously. In this study, we demonstrate that several breast cancer cell lines of different subtypes can be cultured simultaneously in space, resource, and time efficient manner using CELLine AD 1000 systems, allowing the consistent production of vast amounts of EVs for downstream experimentation. We report an improved workflow used for inoculating, maintaining, and monitoring the bioreactors, their EV production, and the characterisation of the EVs produced. Lastly, our proteomic analyses of the EVs produced throughout the lifetime of the bioreactors show that core EV-associated proteins are relatively consistent, with few minor variations over time, but that tracking the production of EVs is a convenient method to indirectly monitor the bioreactor and consistency of the yielded EVs. These findings will aid future studies requiring the simultaneous production of large amounts of EVs from several cell lines of different subtypes of a disease and other EV biomanufacturing applications.

Roles of exosomal circRNAs in tumour immunity and cancer progression

Tumour immunity plays an important role in the development of cancer. Tumour immunotherapy is an important component of antitumour therapy. Exosomes, a type of extracellular vesicle, act as mediators of intercellular communication and molecular transfer and play an essential role in tumour immunity. Circular RNAs (circRNAs) are a new type of noncoding RNA that are enriched within exosomes. In this review, we describe the effects of exosomal circRNAs on various immune cells and the mechanisms of these effects, including macrophages, neutrophils, T cells, and Natural killer (NK) cells. Next, we elaborate on the latest progress of exosome extraction. In addition, the function of exosomal circRNAs as a potential prognostic and drug sensitivity marker is described. We present the great promise of exosomal circRNAs in regulating tumour immunity, predicting patient outcomes, and evaluating drug efficacy.

Case Report: Analysis of Plasma Extracellular Vesicles in a Triple Negative Spindle-Cell Metaplastic Breast Cancer Patient

Metaplastic breast cancer (MpBC) is a rare tumor representing 1% of all breast malignancies. The prognosis of this histologic subtype is actually poor and there are no current clear-cut therapeutic guidelines. Hence, despite its uniqueness, its aggressive prognostic profile strongly encourages further studies to identify new markers and therapeutic targets. Herein, we report a case of 32-years-old patient affected with of triple negative spindle-shaped MpBC. The research of molecular targets on the primary tumor did not allow performing an effective therapeutic choice. Extracellular Vesicles (EVs) are under intense study as new potential pathophysiological markers and targets for therapeutic applications, in different tumors for their role in tumor onset, progression and aggressiveness. Here, we examined the involvement of EVs in this case, to look into the MpBC microenvironment willing to identify new potential molecular targets, pathways of aggressiveness, and markers of prognosis and therapeutic efficacy. Firstly, we characterized MpBC patient EV dimensions and surface proteins. Moreover, we analyzed the EV RNA cargo supposed to be delivered to nearby and distant recipient cells. Interestingly, we observed a dysregulation EV-contained miRNAs, which could determine an increased expression of oncogenes in the tumor microenvironment, probably enabling cancer progression. These data suggest that the characterization of miRNA cargo of EVs could be important for the identification of new markers and for the application of future new target therapies.

Applications of Extracellular Vesicles in Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is the most aggressive and refractory subtype of breast cancer, often occurring in younger patients with poor clinical prognosis. Given the current lack of specific targets for effective intervention, the development of better treatment strategies remains an unmet medical need. Over the last decade, the field of extracellular vesicles (EVs) has grown tremendously, offering immense potential for clinical diagnosis/prognosis and therapeutic applications. While TNBC-EVs have been shown to play an important role in tumorigenesis, chemoresistance and metastasis, they could be repurposed as potential biomarkers for TNBC diagnosis and prognosis. Furthermore, EVs from various cell types can be utilized as nanoscale drug delivery systems (NDDS) for TNBC treatment. Remarkably, EVs generated from specific immune cell subsets have been shown to delay solid tumour growth and reduce tumour burden, suggesting a new immunotherapy approach for TNBC. Intrinsically, EVs can cross the blood-brain barrier (BBB), which holds great potential to treat the brain metastases diagnosed in one third of TNBC patients that remains a substantial clinical challenge. In this review, we present the most recent applications of EVs in TNBC as diagnostic/prognostic biomarkers, nanoscale drug delivery systems and immunotherapeutic agents, as well as discuss the associated challenges and future directions of EVs in cancer immunotherapy.

Tumor-derived extracellular vesicles inhibit HGF/c-Met and EGF/EGFR pathways to accelerate the radiosensitivity of nasopharyngeal carcinoma cells via microRNA-142-5p delivery

Radioresistance prevails as one of the largest obstacles in the clinical treatment of nasopharyngeal carcinoma (NPC). Meanwhile, tumor-derived extracellular vesicles (TEVs) possess the ability to manipulate radioresistance in NPC. However, its mechanism remains to be further explored. Therefore, the current study set out to explore the mechanism of microRNA (miR)-142-5p delivered by TEVs in regard to the radiosensitivity of NPC. Firstly, peripheral blood samples were collected from patients with radioresistance and radiosensitivity, followed by RT-qPCR detection of miR-142-5p expression. A dual-luciferase reporter assay was carried out to elucidate the targeting relationship of miR-142-5p with HGF and EGF. In addition, radiotherapy-resistant NPC cell models were established by screening NPC cells with gradient increasing radiation exposure, and co-incubated with EVs isolated from miR-142-5p mimic-transfected NPC cells, followed by overexpression of HGF and EGF. Moreover, cell viability was detected by means of MTS, cell proliferation with a colony formation assay, cell apoptosis with flow cytometry, and expression patterns of related genes with the help of Western blot analysis. NPC xenotransplantation models in nude mice were also established by subcutaneous injection of 5-8FR cells to determine apoptosis, tumorigenicity, and radiosensitivity in nude mice. It was found that miR-142-5p was poorly expressed in peripheral blood from NPC patients with radioresistance. Mechanistic experimentation illustrated that miR-142-5p inversely targeted HGF and EGF to inactivate the HGF/c-Met and EGF/EGFR pathways, respectively. NPC cell apoptosis was observed to be augmented, while their radioresistance and proliferation were restricted by EVs-miR-142-5p or HGF silencing, or EGF silencing. Furthermore, EVs-miR-142-5p inhibited growth and radioresistance and accelerated the apoptosis of radiotherapy-resistant NPC cells in nude mice by inhibiting the HGF/c-Met and EGF/EGFR pathways. Collectively, our findings indicated that TEVs might inhibit the HGF/c-Met and EGF/EGFR pathways by delivering miR-142-5p into radiotherapy-resistant NPC cells to enhance radiosensitivity in NPC.

Metabolomic Profiling of Blood-Derived Microvesicles in Breast Cancer Patients

Malignant cells differ from benign ones in their metabolome and it is largely unknown whether this difference is reflected in the metabolic profile of their microvesicles (MV), which are secreted into the blood of cancer patients. Here, they are present together with MV from the various blood and endothelial cells. Harvesting MV from 78 breast cancer patients (BC) and 30 controls, we characterized the whole blood MV metabolome using targeted and untargeted mass spectrometry. Especially (lyso)-phosphatidylcholines and sphingomyelins were detected in a relevant abundance. Eight metabolites showed a significant discriminatory power between BC and controls. High concentrations of lysoPCaC26:0 and PCaaC38:5 were associated with shorter overall survival. Comparing BC subtype-specific metabolome profiles, 24 metabolites were differentially expressed between luminal A and luminal B. Pathway analysis revealed alterations in the glycerophospholipid metabolism for the whole cancer cohort and in the ether lipid metabolism for the molecular subtype luminal B. Although this mixture of blood-derived MV contains only a minor number of tumor MV, a combination of metabolites was identified that distinguished between BC and controls as well as between molecular subtypes, and was predictive for overall survival. This suggests that these metabolites represent promising biomarkers and, moreover, that they may be functionally relevant for tumor progression.

Exosomal miRNA profiles of triple-negative breast cancer in neoadjuvant treatment

Triple-negative breast cancer (TNBC) is characterized by aggressive clinicopathological features and is associated with a poor prognosis. Identifying patients that are non-responsive to chemotherapy remains a critical goal for effective personalized therapies. In the present study, the predictive value of exosomal microRNAs (miRNAs) was investigated in patients with TNBC. Exosomes were isolated from patients with TNBC undergoing neoadjuvant chemotherapy. Microarray-based miRNA profiles were compared between patients with pathological complete response (pCR; n=12) and non-pCR (n=12). Furthermore, the miRNA profiles of non-pCR patients with breast cancer recurrence were compared with those with no recurrence. A total of 16 differentially expressed exosomal miRNAs were identified between the patients with pCR and non-pCR by microarray analysis. Of these, a combined signature of four miRNAs (miR-4448, miR-2392, miR-2467-3p and miR-4800-3p) could be used to discriminate between pCR and non-pCR patients with TNBC with an area under the curve value of 0.7652. Furthermore, this study found 43 differentially expressed miRNAs between the patients with non-pCR and recurrence and non-pCR patients without recurrence. In network analysis, 'pathway in cancer', 'focal adhesion' and 'cell cycle' were identified as the crucial pathways in patients with non-pCR who also developed recurrence. Several exosomal miRNAs may be useful biomarkers to predict treatment efficacy for TNBC. The present study identified patients who were resistant to standard chemotherapy and therefore more likely to develop breast cancer recurrence.

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.

Role of breast cancer-derived exosomes in metabolism of immune cells through PD1-GLUT1-HK2 metabolic axis

Tumor cells modulate immune responses by secreting exosomes. Tumor exosomes can affect the metabolism of immune cells and increase immune inhibitory molecules such as programmed cell death protein 1 (PD-1). PD-1 inhibits the glycolysis pathway in immune cells. We investigated the role of tumor exosomes in how metabolic changes occur through the PD1-GLUT1-HK2 metabolic axisin peripheral blood mononuclear cells (PBMCs). The MDA-MB-231 cell line was cultured, serum samples from breast cancer patients were collected, and exosomes purified from serum samples and the MDA-MB-231 cell line. PBMCs were treated with purified exosomes for 72 h and, the expression of PD1-GLUT1-HK2 genes was measured by real-time PCR. Our study results showed relative expression of the HK2 gene in both groups treated with MDA-MB-231 cell line exosomes and serum exosomes of breast cancer patients was significantly increased compared to the control group (p < 0.0001). Also, the relative expression of the PD1 gene and GLUT1 gene showed a significant increase compared to the control group only in the group treated with MDA-MB-231 cell line exosomes (p < 0.0001). Therefore, Breast cancer exosomes increased the expression of key genes in the glycolysis pathway, increasing the glycolysis pathway in PBMCs. Increased expression of PD-1 could not prevent the expression of critical genes in the glycolysis pathway as in previous studies.

Extracellular Vesicles Carry lncRNA SNHG16 to Promote Metastasis of Breast Cancer Cells via the miR-892b/PPAPDC1A Axis

Breast cancer (BC) represents the most commonly diagnosed malignancy among women. Long non-coding RNAs (lncRNAs) can be transferred by extracellular vesicles (EVs) to participate in BC progression. This study demonstrated that SNHG16 expression was significantly increased in BC tissues and cells. Overexpression of SNHG16 promoted the migration, invasion, and epithelial-mesenchymal transition (EMT) of BC cells. SNHG16 was carried by EVs. Bioinformatics analysis predicted that SNHG16 regulated PPAPDC1A expression by sponging miR-892b, which was confirmed by RNA-fluorescence in situ hybridization (FISH), RT-qPCR, dual-luciferase gene reporter assay, and RNA immunoprecipitation (RIP). MDA-MB-157 and HS578T cells were transfected with pcDNA3.1-SNHG16, miR-892b-mimic, or si-PPAPDC1A for functional rescue experiments in vitro, and the cells were treated with MDA-MB-231 cell-derived EVs. The results confirmed that enhanced miR-892b expression partially eliminated the increase of migration, invasion, and EMT of BC cells mediated by SNHG16 or EVs. The lung metastasis model in nude mice was established by injecting HS578T cells via tail vein. The results showed that si-SNHG16 reduced the metastatic nodules and decreased the vimentin expression. In conclusion, EVs derived from BC cells transferred SNHG16 via the miR-892b/PPAPDC1A axis, thus promoting EMT, migration, and invasion of BC.

Proteomic Profiling of Ectosomes Derived from Paired Urothelial Bladder Cancer and Normal Cells Reveals the Presence of Biologically-Relevant Molecules

Protein content of extracellular vesicles (EVs) can modulate different processes during carcinogenesis. Novel proteomic strategies have been applied several times to profile proteins present in exosomes released by urothelial bladder cancer (UBC) cells. However, similar studies have not been conducted so far on another population of EVs, i.e., ectosomes. In the present study we used a shotgun nanoLC-MS/MS proteomic approach to investigate the protein content of ectosomes released in vitro by T-24 UBC cells and HCV-29 normal ureter epithelial cells. In addition, cancer-promoting effects exerted by UBC-derived ectosomes on non-invasive cells in terms of cell proliferation and migratory properties were assessed. In total, 1158 proteins were identified in T-24-derived ectosomes, while HCV-29-derived ectosomes contained a lower number of 259 identified proteins. Qualitative analysis revealed 938 proteins present uniquely in T-24-derived ectosomes, suggesting their potential applications in bladder cancer management as diagnostic and prognostic biomarkers. In addition, T-24-derived ectosomes increased proliferation and motility of recipient cells, likely due to the ectosomal transfer of the identified cancer-promoting molecules. The present study provided a focused identification of biologically relevant proteins in UBC-derived ectosomes, confirming their role in UBC development and progression, and their applicability for further biomarker-oriented studies in preclinical or clinical settings.

Role of Src/FAK in migration and invasion mediated by extracellular vesicles from MDA-MB-231 cells stimulated with linoleic acid

Linoleic acid (LA) is the most abundant polyunsaturated fatty acid in occidental diets, which mediate a variety of processes in human breast cancer cells, including migration and invasion. Extracellular vesicles (EVs) are vesicles released from endosomes and plasma membrane that are composed of a variety of molecules, including proteins, nucleic acids and lipids. EVs from cancer cells promote processes related with cancer progression. In the present study, we demonstrate that treatment of MDA-MB-231 cells with EVs from MDA-MB-231 cells stimulated with LA (LA EVs) promote migration and invasion via Src activity. LA EVs induce activation of FAK via Src activity and of Src and Akt2. LA EVs also induce the assembly of focal adhesions and MMP-9 secretion. These findings demonstrate that LA EVs mediate an autocrine and/or paracrine Src/FAK signaling pathway to promote migration and invasion.

Urinary Exosomal MicroRNAs as Potential Non-invasive Biomarkers in Breast Cancer Detection

INTRODUCTION

Breast cancer (BC) is the most frequent malignant disease in women worldwide and is therefore challenging for the healthcare system. Early BC detection remains a leading factor that improves overall outcome and disease management. Aside from established screening procedures, there is a constant demand for additional BC detection methods. Routine BC screening via non-invasive liquid biopsy biomarkers is one auspicious approach to either complete or even replace the current state-of-the-art diagnostics. The study explores the diagnostic potential of urinary exosomal microRNAs with specific BC biomarker characteristics to initiate the potential prospective application of non-invasive BC screening as routine practice.

METHODS

Based on a case-control study (69 BC vs. 40 healthy controls), expression level quantification and subsequent biostatistical computation of 13 urine-derived microRNAs were performed to evaluate their diagnostic relevance in BC.

RESULTS

Multilateral statistical assessment determined and repeatedly confirmed a specific panel of four urinary microRNA types (miR-424, miR-423, miR-660, and let7-i) as a highly specific combinatory biomarker tool discriminating BC patients from healthy controls, with 98.6% sensitivity and 100% specificity.

DISCUSSION

Urine-based BC diagnosis may be achieved through the analysis of distinct microRNA panels with proven biomarker abilities. Subject to further validation, the implementation of urinary BC detection in routine screening offers a promising non-invasive alternative in women's healthcare.

Environmental control of mammary carcinoma cell expansion by acidification and spheroid formation in vitro

Breast cancer is the leading cause of cancer death among women worldwide. Like other cancers, mammary carcinoma progression involves acidification of the tumor microenvironment, which is an important factor for cancer detection and treatment strategies. However, the effects of acidity on mammary carcinoma cell morphology and phenotype have not been thoroughly characterized. Here, we evaluated fundamental effects of environmental acidification on mammary carcinoma cells in standard two-dimensional cultures and three-dimensional spheroids. Acidification decreased overall mammary carcinoma cell viability, while increasing their resistance to the anthracycline doxorubicin. Environmental acidification also increased extracellular vesicle production by mammary carcinoma cells. Conditioned media containing these vesicles appeared to increase fibroblast motility. Acidification also increased mammary carcinoma cell motility when cultured with fibroblasts in spheroids. Taken together, results from this study suggest that environmental acidification induces drug resistance and extracellular vesicle production by mammary carcinoma cells that promote tumor expansion.

Liquid biopsies and cancer omics

The development of the sequencing technologies allowed the generation of huge amounts of molecular data from a single cancer specimen, allowing the clinical oncology to enter the era of the precision medicine. This massive amount of data is highlighting new details on cancer pathogenesis but still relies on tissue biopsies, which are unable to capture the dynamic nature of cancer through its evolution. This assumption led to the exploration of non-tissue sources of tumoral material opening the field of liquid biopsies. Blood, together with body fluids such as urines, or stool, from cancer patients, are analyzed applying the techniques used for the generation of omics data. With blood, this approach would allow to take into account tumor heterogeneity (since the circulating components such as CTCs, ctDNA, or ECVs derive from each cancer clone) in a time dependent manner, resulting in a somehow "real-time" understanding of cancer evolution. Liquid biopsies are beginning nowdays to be applied in many cancer contexts and are at the basis of many clinical trials in oncology.

Rational Synthesis of Aptamer-Functionalized Polyethylenimine-Modified Magnetic Graphene Oxide Composites for Highly Efficient Enrichment and Comprehensive Metabolomics Analysis of Exosomes

Exosomes, which are phospholipid bilayer nanovesicles, can transfer their content to recipient cells, playing a crucial role in intercellular communication. Exosomes have emerged as promising cancer biomarkers. However, a convenient, efficient, and economical approach for their isolation and comprehensive analysis is still technically challenging. In this study, aptamer-based immunoaffinitive magnetic composites, MagG@PEI@DSP@aptamer, were prepared to achieve the convenient capture, efficient enrichment, and mild release of exosomes. The constructed composites contain three segments: a PEI-modified magnetic graphene scaffold, an aptamer CD63 sequence, and a cleavable cross-linker in between. Notably, the binding capacity of MagG@PEI@DSP for an aptamer is 93 nmol/mg, and per milligram MagG@PEI@DSP@aptamer could capture 450 μg exosomes. Moreover, the released exosomes from MagG@PEI@DSP@aptamer composites were intact and well-dispersed. The prepared composites were then applied to profile the metabolite composition of exosomes secreted by breast cancer cells MCF-7, and the number of detected features was obviously increased when compared to that obtained by the traditional ultracentrifugation method (4528 vs 3710 and 3967 vs 3785 in the positive and negative ionization modes). Besides, the exosomes secreted by MCF-7 and normal breast cells MCF-10A were isolated from cell culture medium with MagG@PEI@DSP@aptamer, and their metabolic profiles were then comprehensively analyzed; in total, 119 metabolites in MCF-7 and MCF-10A were identified. Compared with exosomes from MCF-10A, 43 and 42 metabolites were upregulated and downregulated, respectively, in those from MCF-7. These data showed that the prepared MagG@PEI@DSP@aptamer composites can be used to effectively capture exosomes and further for metabolomics analysis.

Proteomic analysis of circulating extracellular vesicles identifies potential markers of breast cancer progression, recurrence, and response

Proteomic profiling of circulating small extracellular vesicles (sEVs) represents a promising, noninvasive approach for early detection and therapeutic monitoring of breast cancer (BC). We describe a relatively low-cost, fast, and reliable method to isolate sEVs from plasma of BC patients and analyze their protein content by semiquantitative proteomics. sEV-enriched fractions were isolated from plasma of healthy controls and BC patients at different disease stages before and after surgery. Proteomic analysis of sEV-enriched fractions using reverse phase protein array revealed a signature of seven proteins that differentiated BC patients from healthy individuals, of which FAK and fibronectin displayed high diagnostic accuracy. The size of sEVs was significantly reduced in advanced disease stage, concomitant with a stage-specific protein signature. Furthermore, we observed protein-based distinct clusters of healthy controls, chemotherapy-treated and untreated postsurgery samples, as well as a predictor of high risk of cancer relapse, suggesting that the applied methods warrant development for advanced diagnostics.

Hypoxia-induced miR-3677-3p promotes the proliferation, migration and invasion of hepatocellular carcinoma cells by suppressing SIRT5

Hepatocellular carcinoma (HCC), with life‐threatening malignant behaviours, often develops distant metastases and is the fourth most common primary cancer in the world, having taken millions of lives in Asian countries such as China. The novel miR‐3677‐3p is involved in a high‐expression‐related poor prognosis in HCC tissues and cell lines, indicating oncogenesis functions in vitro and in vivo. Initially, we confirmed the inhibition of proliferation, migration and invasion in miR‐3677‐3p knock‐down MHCC‐97H and SMMC‐7721 cell lines, which are well known for their high degree of invasiveness. Then, we reversed the functional experiments in the low‐miR‐3677‐3p‐expression Hep3B cell line via overexpressing miR‐3677‐3p. In nude mice xenograft and lung metastasis assays, we found suppressor behaviours, smaller nodules and low density of organ spread, after injection of cells transfected with shRNA‐miR‐3677‐3p. A combination of databases (Starbase, TargetScan and MiRgator) illustrated miR‐3677‐3p targets, and it was shown to suppress the expression of SIRT5 in a dual‐luciferase reporter system. To clarify the conclusions of previous ambiguous research, we up‐regulated SIRT5 in Hep3B cells, and rescue tests were established for confirmation that miR‐3677‐3p suppresses SIRT5 to enhance the migration and invasion of HCC. Interestingly, we discovered hypoxia‐induced miR‐3677‐3p up‐regulation benefited HCC malignancy and invasiveness. In conclusion, the overexpression of miR‐3677‐3p mediated SIRT5 inhibition, which could increase proliferation, migration and invasion of HCC in hypoxic microenvironments.

Breast Cancer Derived Extracellular Vesicles in Bone Metastasis Induction and Their Clinical Implications as Biomarkers

Cancer incidence and mortality are rapidly growing worldwide. The main risk factors for cancer can be associated with aging as well as the growth of the population and socioeconomic condition. Breast cancer, a crucial public health problem, is the second cause of death among women. About 70% of patients with advanced breast cancer have bone metastases. In bone metastasis, cancer cells and osteoclasts form a vicious cycle: cancer cells promote osteoclast differentiation and activation that, in turn, induce cancer cell seeding and proliferation in the bone. Growing evidence shows that extracellular vesicles (EVs) play a key role in carcinogenesis, proliferation, pre-metastatic niche formation, angiogenesis, metastasis, and chemoresistance in several tumors, such as breast, lung, prostate, and liver cancer. Here, we discuss the role of EVs released by breast cancer cells, focusing on bone metastasis induction and their clinical implications as biomarkers.

Tumor microenvironment: Challenges and opportunities in targeting metastasis of triple negative breast cancer

Triple negative breast cancer (TNBC) is most aggressive subtype of breast cancers with high probability of metastasis as well as lack of specific targets and targeted therapeutics. TNBC is characterized with unique tumor microenvironment (TME), which differs from other subtypes. TME is associated with induction of proliferation, angiogenesis, inhibition of apoptosis and immune system suppression, and drug resistance. Exosomes are promising nanovesicles, which orchestrate the TME by communicating with different cells within TME. The components of TME including transformed ECM, soluble factors, immune suppressive cells, epigenetic modifications and re-programmed fibroblasts together hamper antitumor response and helps progression and metastasis of TNBCs. Therefore, TME could be a therapeutic target of TNBC. The current review presents latest updates on the role of exosomes in modulation of TME, approaches for targeting TME and combination of immune checkpoint inhibitors and target chemotherapeutics. Finally, we also discussed various phytochemicals that alter genetic, transcriptomic and proteomic profiles of TME along with current challenges and future implications. Thus, as TME is associated with the hallmarks of TNBC, the understanding of the impact of different components can improve the clinical benefits of TNBC patients.

miR-1254 inhibits progression of glioma in vivo and in vitro by targeting CSF-1

The role of miRNAs (microRNAs) has been implicated in glioma initiation and progression, although the inherent biochemical mechanisms still remain to be unravelled. This study strived to evaluate the association between CSF‐1 and miR‐1254 and their effect on advancement of glioma cells. The levels of miR‐1254 in glioma cells and tissues were determined by real‐time RT‐PCR. Proliferation, apoptosis and cell cycle arrest, invasion and migration, were assessed by CCK‐8 assay, colony formation assay, flow cytometry, transwell assay and wound‐healing assay, respectively. The targeted relationship between miR‐1254 and CSF‐1 was confirmed by dual‐luciferase reporter assay. The effects of CSF‐1 on cellular functions were also assessed. The in vivo effect of miR‐1254 on the formation of a tumour was explored by using the mouse xenograft model. We found in both glioma tissues and glioma cells, the down‐regulated expressions of miR‐1254 while that of CSF‐1 was abnormally higher than normal level. The target relationship between CSF‐1 and miR‐1254 was validated by dual‐luciferase reporter assay. The CSF‐1 down‐regulation or miR‐1254 overexpression impeded the invasion, proliferation and migratory ability of U251 and U87 glioma cells, concurrently occluded the cell cycle and induced cell apoptosis. Moreover, in vivo tumour development was repressed due to miR‐1254 overexpression. Thus, CSF‐1 is targeted directly by miR‐1254, and the miR‐1254/CSF‐1 axis may be a potential diagnostic target for malignant glioma.