The roles of exosomes in cancer drug resistance and its therapeutic application

The theragnostic advances of exosomes in managing leukaemia

Leukaemia, a group of haematological malignancies, presents ongoing diagnosis, prognosis, and treatment challenges. A major obstacle in treating this disease is the development of drug resistance. Overcoming drug resistance poses a significant barrier to effective leukaemia treatment. The emergence of exosome research has unveiled new insights into the probable theragnostic implementations in leukaemia. Various research has exhibited the diagnostic possibilities of exosomes in identifying leukaemia-specific biomarkers, including genetic mutations and fusion transcripts. Additionally, exosomes have been implicated in disease progression and treatment response, rendering them appealing targets for therapeutics. Exosomes, originating from diverse cell types, are instrumental in intercellular communication as they participate in the functional transportation of molecules like proteins, nucleic acids and lipids across space. Exosomes have a dual role in immune regulation, mediating immune suppression and modulating anti-leukaemia immune responses. Interestingly, exosomes can even act as drug transport vehicles. This review delves into the intricate process of exosome biogenesis, shedding light on their formation and release from donor cells. The key mechanisms engaged in exosome biogenesis, for instance, the endosomal sorting complexes required for transport (ESCRT) machinery and ESCRT-independent pathways, are thoroughly discussed. Looking ahead, future approaches that leverage innovative technologies hold the promise of revolutionizing disease management and improving patient outcomes.

CircSLC4A7 in resistant-cells-derived exosomes promotes docetaxel resistance via the miR-1205/MAPT axis in prostate cancer

Prostate cancer (PCa) is a high-mortality cancer. Docetaxel (DCT) combined with second-generation anti-androgens is considered the golden standard therapy for PCa, whose application is limited for DCT resistance (DR). Therefore, exploring the mechanism of DR is of great importance. In this study, PCa cell lines of PC3 and DU145 were employed, and DR cells were constructed by treatment with graded DCT. CircSLC4A7, miR-1205, and microtubule-associated protein tau (MAPT) transfections were established. Cell counting kit-8 assay was performed to evaluate the cell activity and IC50 of DCT. After being treated with DCT, DR was assessed by colony formation assay, flow cytometry analysis, and terminal transferase-mediated UTP nick end-labeling assay. Real-time quantitative PCR and western blotting analysis evaluated the expression levels of genes. The dual-luciferase reporter gene assay verified the miR-1205 binding sites with circSLC4A7 and MAPT. An animal experiment was performed to assess the tumor growth influenced by circSLC4A7. After conducting DR cells and isolated exosomes, we found that not only co-culture with DR cells but also treatment with DR cells' exosomes would promote the DR of normal cells. Moreover, circSLC4A7 was highly expressed in DR cells and their exosomes. CircSLC4A7 overexpression enhanced DR, represented as raised IC50 of DCT, increased colony formation, and decreased cell apoptosis after DCT treatment, while circSLC4A7 knockdown had the opposite effect. MiR-1205 was confirmed as a circSLC4A7-sponged miRNA and miR-1205 inhibitor reversed the effect of sh-circSLC4A7. MAPT was further identified as a target of miR-1205 and had a similar effect with circSLC4A7. The effect of circSLC4A7 on DR was also confirmed by xenograft experiments. Collectively, circSLC4A7 in resistant-cells-derived exosomes promotes DCT resistance of PCa via miR-1205/MAPT axis, which may provide a new treatment strategy for DR of PCa.

Exosomes and tumor virus interlink: A complex side of cancer

Extracellular Vesicles (EVs) based cancer research reveals several complicated sides of cancer. EVs are classified as several subpopulations such as microvesicles, apoptotic bodies, and exosomes. In cancer, exosomes play a significant role as a cellular messenger in tumor development and progression. Tumor-derived exosomes (TEXs) are also a theranostic tool for cancer. Tumor virus-infected cell-derived EVs promote cancer development. Exosomes (a subpopulation of EVs) play a significant role in converting noninfecting cells to infected cells. It transports several biological active cargo (DNA, RNA, protein, and virions) towards the noninfected cells. This cellular transport enhances infection rates via reprogramming of noninfected cells. In this review, we explore tumor viruses, exosomes and tumor viruses interlink, the theranostic landscape of exosomes in tumor virus-associated cancer and the future orientation of exosomes-based virus oncology.

The role and clinical applications of exosomes in cancer drug resistance

Tumor-secreted exosomes are heterogeneous multi-signal messengers that support cancer growth and dissemination by mediating intercellular crosstalk and activating signaling pathways. Distinct from previous reviews, we focus intently on exosome-therapeutic resistance dynamics and summarize the new findings about the regulation of cancer treatment resistance by exosomes, shedding light on the complex processes via which these nanovesicles facilitate therapeutic refractoriness across various malignancies. Future research in exosome biology can potentially transform diagnostic paradigms and therapeutic interventions for cancer management. This review synthesizes recent insights into the exosome-driven regulation of cancer drug resistance, illuminates the sophisticated mechanisms by which these nanovesicles facilitate therapeutic refractoriness across various malignancies, and summarizes some strategies to overcome drug resistance.

Advances in tumor stroma-based targeted delivery

The tumor stroma plays a crucial role in tumor progression, and the interactions between the extracellular matrix, tumor cells, and stromal cells collectively influence tumor progression and the efficacy of therapeutic agents. Currently, utilizing components of the tumor stroma for drug delivery is a noteworthy strategy. A number of targeted drug delivery systems designed based on tumor stromal components are entering clinical trials. Therefore, this paper provides a thorough examination of the function of tumor stroma in the advancement of targeted drug delivery systems. One approach is to use tumor stromal components for targeted drug delivery, which includes certain stromal components possessing inherent targeting capabilities like HA, laminin, along with targeting stromal cells homologously. Another method entails directly focusing on tumor stromal components to reshape the tumor stroma and facilitate drug delivery. These drug delivery systems exhibit great potential in more effective cancer therapy strategies, such as precise targeting, enhanced penetration, improved safety profile, and biocompatibility. Ultimately, the deployment of these drug delivery systems can deepen our comprehension of tumor stroma and the advanced development of corresponding drug delivery systems.

Exosomal miRNA as biomarker in cancer diagnosis and prognosis: A review

Exosomes, which are extracellular vesicles with a diameter ranging from 40 to 160 nm, are abundantly present in various body fluids. Exosomal microRNA (ex-miR), due to its exceptional sensitivity and specificity, has garnered significant attention. Notably, ex-miR is consistently detected in almost all bodily fluids, highlighting its potential as a reliable biomarker. This attribute of ex-miR has piqued considerable interest in its application as a diagnostic tool for the early detection, continuous monitoring, and prognosis evaluation of cancer. Given the critical role of exosomes and their cargo in cancer biology, this review explores the intricate processes of exosome biogenesis and uptake, their multifaceted roles in cancer development and progression, and the potential of ex-miRs as biomarkers for tumor diagnosis and prognosis.

Identification of key lncRNAs associated with oxaliplatin resistance in colorectal cancer cells and isolated exosomes: From In-Silico prediction to In-Vitro validation

One of the critical challenges in managing colorectal cancer (CRC) is the development of oxaliplatin (OXP) resistance. Long non-coding RNAs (lncRNAs) have a crucial role in CRC progression and chemotherapy resistance, with exosomal lncRNAs emerging as potential biomarkers. This study aimed to predict key lncRNAs involved in OXP-resistance using in-silico methods and validate them using RT-qPCR methods in CRC cells and their isolated exosomes. Two public datasets, GSE42387 and GSE119481, were downloaded from the GEO database to identify differentially expressed genes (DEGs) and miRNAs (DEmiRNAs) associated with OXP-resistance in the HCT116 cell line. The analysis of GSE42387 revealed 210 DEGs, and GSE119481 identified 73 DEmiRNAs. A protein-protein interaction (PPI) network analysis of the DEGs identified 133 interconnected genes, from which the top ten genes with the highest degree scores were selected. By intersecting predicted miRNAs targeting these genes with the DEmiRNAs, 38 common miRNAs were found. Subsequently, 224 lncRNAs targeting these common miRNAs were predicted. LncRNA-miRNA-mRNA network were constructed and the top five lncRNAs with the highest degree scores were identified. Analysis using the Kaplan-Meier plotter database revealed that the key lncRNAs NEAT1, OIP5-AS1, and MALAT1 are significantly associated with the overall survival of CRC patients. To validate these lncRNAs, OXP-resistant HCT116 sub-cell line (HCT116/OXR) was developed by exposing parental HCT116 cells to gradually increasing concentrations of OXP. Exosomes derived from both HCT116 and HCT116/OXR cells were isolated and characterized utilizing dynamic light scattering (DLS), transmission electron microscopy (TEM), and Western blotting. RT-qPCR confirmed elevated levels of NEAT1, OIP5-AS1, and MALAT1 in HCT116/OXR cells and their exosomes compared to parental HCT116 cells and their exosomes. This study concludes that NEAT1, OIP5-AS1, and MALAT1 are associated with the OXP-resistance in CRC. The high levels of these lncRNAs in exosomes of resistant cells suggest their involvement in intercellular communication and resistance propagation. This positioning makes them promising biomarkers for OXP-resistance in CRC.

RNAs in tumour-derived extracellular vesicles and their significance in the tumour microenvironment

Small extracellular vesicles (sEVs) secreted by various types of cells serve as crucial mediators of intercellular communication within the complex tumour microenvironment (TME). Tumour-derived small extracellular vesicles (TDEs) are massively produced and released by tumour cells, recapitulating the specificity of their cell of origin. TDEs encapsulate a variety of RNA species, especially messenger RNAs, microRNAs, long non-coding RNAs, and circular RNAs, which release to the TME plays multifaced roles in cancer progression through mediating cell proliferation, invasion, angiogenesis, and immune evasion. sEVs act as natural delivery vehicles of RNAs and can serve as useful targets for cancer therapy. This review article provides an overview of recent studies on TDEs and their RNA cargo, with emphasis on the role of these RNAs in carcinogenesis.

Targeting non-coding RNAs to overcome osimertinib resistance in EGFR-mutated non-small cell lung cancer

Osimertinib, a third-generation inhibitor of epidermal growth factor receptor (EGFR) tyrosine kinase, exhibits remarkable efficacy in prolonging the survival of patients with non-small cell lung cancer (NSCLC) carrying EGFR mutations, surpassing the efficacy of first- and second-generation EGFR tyrosine kinases. Nevertheless, the emergence of osimertinib resistance is inevitable, necessitating an investigation into the underlying mechanisms. Increasing evidence has revealed that non-coding RNAs (ncRNAs), including microRNAs, long ncRNAs, and circular RNAs, play a significant role in the development and progression of lung cancer. These ncRNAs regulate essential signaling pathways, offering a novel avenue for understanding the fundamental mechanisms of osimertinib resistance. Recent studies have reported the significant impact of ncRNAs on osimertinib resistance, achieved through various mechanisms that modulate treatment sensitivity. We provide a concise overview of the functions and underlying mechanisms of extensively researched ncRNAs in the development of osimertinib resistance and emphasize their potential clinical application in EGFR-mutated NSCLC resistant to osimertinib. Finally, we discuss the obstacles that must be addressed to effectively translate ncRNA-based approaches into clinical practice.

Subcellular Drug Distribution: Exploring Organelle-Specific Characteristics for Enhanced Therapeutic Efficacy

The efficacy and potential toxicity of drug treatments depends on the drug concentration at its site of action, intricately linked to its distribution within diverse organelles of mammalian cells. These organelles, including the nucleus, endosome, lysosome, mitochondria, endoplasmic reticulum, Golgi apparatus, lipid droplets, exosomes, and membrane-less structures, create distinct sub-compartments within the cell, each with unique biological features. Certain structures within these sub-compartments possess the ability to selectively accumulate or exclude drugs based on their physicochemical attributes, directly impacting drug efficacy. Under pathological conditions, such as cancer, many cells undergo dynamic alterations in subcellular organelles, leading to changes in the active concentration of drugs. A mechanistic and quantitative understanding of how organelle characteristics and abundance alter drug partition coefficients is crucial. This review explores biological factors and physicochemical properties influencing subcellular drug distribution, alongside strategies for modulation to enhance efficacy. Additionally, we discuss physiologically based computational models for subcellular drug distribution, providing a quantifiable means to simulate and predict drug distribution at the subcellular level, with the potential to optimize drug development strategies.

Molecular insights to therapeutic in cancer: role of exosomes in tumor microenvironment, metastatic progression and drug resistance

Exosomes play a pivotal part in cancer progression and metastasis by transferring various biomolecules. Recent research highlights their involvement in tumor microenvironment remodeling, mediating metastasis, tumor heterogeneity and drug resistance. The unique cargo carried by exosomes garners the interest of researchers owing to its potential as a stage-specific biomarker for early cancer detection and its role in monitoring personalized treatment. However, unanswered questions hinder a comprehensive understanding of exosomes and their cargo in this context. This review discusses recent advancements and proposes novel ideas for exploring exosomes in cancer progression, aiming to deepen our understanding and improve treatment approaches.

Composition, functions, and applications of exosomal membrane proteins

Exosomes play a crucial role in various biological processes, such as human development, immune responses, and disease occurrence. The membrane proteins on exosomes are pivotal factors for their biological functionality. Currently, numerous membrane proteins have been identified on exosome membranes, participating in intercellular communication, mediating target cell recognition, and regulating immune processes. Furthermore, membrane proteins from exosomes derived from cancer cells can serve as relevant biomarkers for early cancer diagnosis. This article provides a comprehensive review of the composition of exosome membrane proteins and their diverse functions in the organism's biological processes. Through in-depth exploration of exosome membrane proteins, it is expected to offer essential foundations for the future development of novel biomedical diagnostics and therapies.

Exosomes: a significant medium for regulating drug resistance through cargo delivery

Exosomes are small lipid nanovesicles with a diameter of 30-150 nm. They are present in all body fluids and are actively secreted by the majority of cells through the process of exocytosis. Exosomes play an essential role in intercellular communication and act as significant molecular carriers in regulating various physiological and pathological processes, such as the emergence of drug resistance in tumors. Tumor-associated exosomes transfer drug resistance to other tumor cells by releasing substances such as multidrug resistance proteins and miRNAs through exosomes. These substances change the cell phenotype, making it resistant to drugs. Tumor-associated exosomes also play a role in impacting drug resistance in other cells, like immune cells and stromal cells. Exosomes alter the behavior and function of these cells to help tumor cells evade immune surveillance and form a tumor niche. In addition, exosomes also export substances such as tumoricidal drugs and neutralizing antibody drugs to help tumor cells resist drug therapy. In this review, we summarize the mechanisms of exosomes in promoting drug resistance by delivering cargo in the context of the tumor microenvironment (TME).

Mechanisms, combination therapy, and biomarkers in cancer immunotherapy resistance

Anti-programmed death 1/programmed death ligand 1 (anti-PD-1/PD-L1) antibodies exert significant antitumor effects by overcoming tumor cell immune evasion and reversing T-cell exhaustion. However, the emergence of drug resistance causes most patients to respond poorly to these immune checkpoint inhibitors (ICIs). Studies have shown that insufficient T-cell infiltration, lack of PD-1 expression, deficient interferon signaling, loss of tumor antigen presentation, and abnormal lipid metabolism are all considered to be closely associated with immunotherapy resistance. To address drug resistance in tumor immunotherapy, a lot of research has concentrated on developing combination therapy strategies. Currently, ICIs such as anti-PD-1 /PD-L1 antibody combined with chemotherapy and targeted therapy have been approved for clinical treatment. In this review, we analyze the mechanisms of resistance to anti-PD-1/PD-L1 therapy in terms of the tumor microenvironment, gut microbiota, epigenetic regulation, and co-inhibitory immune checkpoint receptors. We also discuss various promising combination therapeutic strategies to address resistance to anti-PD-1/PD-L1 drugs, including combining these therapies with traditional Chinese medicine, non-coding RNAs, targeted therapy, other ICIs, and personalized cancer vaccines. Moreover, we focus on biomarkers that predict resistance to anti-PD-1/PD-L1 therapy as well as combination therapy efficacy. Finally, we suggest ways to further expand the application of immunotherapy through personalized combination strategies using biomarker systems.

Extracellular vesicles in cattle infected with bovine leukaemia virus: isolation and molecular analysis

Introduction

Exosomes are nanosized lipid bilayer membranous microvesicles, extracellularly released from a variety of mammalian cells. They mediate intercellular signalling by transporting several types of RNA, lipids and proteins and participate in the intercellular exchange of DNA, RNA, micro RNA, proteins and other components. These microvesicles are present in all body fluids in physiological and pathological conditions and reflect the state of the host organism. The aim of the study was the isolation and molecular determination of exosomes in blood and supernatant fluids of bovine dendritic cell cultures infected with bovine leukaemia virus (BLV).

Material and Methods

Exosomes were isolated by ultracentrifugation from the blood sera, plasma and supernatant of bovine BLV-infected and uninfected control dendritic cell cultures and their presence was confirmed with scanning electron and transmission electron microscopy. Western blot analysis of the structural BLV glycoprotein 51 (Env) and protein 24 (Gag) and of the tetraspanin exosomal markers CD9, CD63 and flotillin-1 was undertaken in BLV+ and control BLV- cattle.

Results

In exosomes of leukaemic cattle both BLV proteins and exosomal markers were detected. In healthy control animals only exosomal markers were determined.

Conclusion

Proteins of BLV were released with exosomes and could be transferred into recipient cells as an alternative propagation route not requiring virus infection.

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

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

The strict regulation of HIF-1α by non-coding RNAs: new insight towards proliferation, metastasis, and therapeutic resistance strategies

The hypoxic environment is prominently witnessed in most solid tumors and is associated with the promotion of cell proliferation, epithelial-mesenchymal transition (EMT), angiogenesis, metabolic reprogramming, therapeutic resistance, and metastasis of tumor cells. All the effects are mediated by the expression of a transcription factor hypoxia-inducible factor-1α (HIF-1α). HIF-1α transcriptionally modulates the expression of genes responsible for all the aforementioned functions. The stability of HIF-1α is regulated by many proteins and non-coding RNAs (ncRNAs). In this article, we have critically discussed the crucial role of ncRNAs [such as microRNAs (miRNAs), long non-coding RNAs (lncRNAs), circular RNAs (circRNAs), Piwi-interacting RNAs (piRNAs), and transfer RNA (tRNA)-derived small RNAs (tsRNAs)] in the regulation of stability and expression of HIF-1α. We have comprehensively discussed the molecular mechanisms and relationship of HIF-1α with each type of ncRNA in either promotion or repression of human cancers and therapeutic resistance. We have also elaborated on ncRNAs that are in clinical examination for the treatment of cancers. Overall, the majority of aspects concerning the relationship between HIF-1α and ncRNAs have been discussed in this article.

Inhalable dry powders of microRNA-laden extracellular vesicles prepared by thin-film freeze-drying

Extracellular vesicles (EVs) are endogenous vesicles that comprise a variety of submicron vesicular structures. Among these, exosomes have been widely investigated as delivery systems for small and large molecules. Herein, the thin-film freeze-drying technology was utilized to engineer aerosolizable dry powders of miR-335-laden induced EVs (iEV-335) generated in B cells for potential delivery into the lung to treat primary lung cancer and/or pulmonary metastases. The size distribution, structure, and morphology of iEV-335 were preserved after they were subjected to thin-film freeze-drying with the proper excipients. Importantly, iEV-335, in liquid or reconstituted from thin-film freeze-dried powders, were equally effective in downregulating SOX4 gene expression in LM2 human triple-negative mammary cancer cells. The iEV-335 dry powder compositions showed mass median aerodynamic diameters (MMAD) of around 1.2 µm with > 60 % of the emitted doses had an MMAD of ≤ 3 µm, indicating that the powders can potentially achieve efficient deposition within the alveolar region following oral inhalation, which is desirable for treatment of primary lung cancer and pulmonary metastases. Overall, it is concluded that it is feasible to apply thin-film freeze-drying to prepare aerosolizable dry powders of iEVs for pulmonary delivery.

Unveiling the mechanisms and challenges of cancer drug resistance

Cancer treatment faces many hurdles and resistance is one among them. Anti-cancer treatment strategies are evolving due to innate and acquired resistance capacity, governed by genetic, epigenetic, proteomic, metabolic, or microenvironmental cues that ultimately enable selected cancer cells to survive and progress under unfavorable conditions. Although the mechanism of drug resistance is being widely studied to generate new target-based drugs with better potency than existing ones. However, due to the broader flexibility in acquired drug resistance, advanced therapeutic options with better efficacy need to be explored. Combination therapy is an alternative with a better success rate though the risk of amplified side effects is commonplace. Moreover, recent groundbreaking precision immune therapy is one of the ways to overcome drug resistance and has revolutionized anticancer therapy to a greater extent with the only limitation of being individual-specific and needs further attention. This review will focus on the challenges and strategies opted by cancer cells to withstand the current therapies at the molecular level and also highlights the emerging therapeutic options -like immunological, and stem cell-based options that may prove to have better potential to challenge the existing problem of therapy resistance. Video Abstract.

Recent Progress in Phage-Based Nanoplatforms for Tumor Therapy

Nanodrug delivery systems have demonstrated a great potential for tumor therapy with the development of nanotechnology. Nonetheless, traditional drug delivery systems are faced with issues such as complex synthetic procedures, low reproducibility, nonspecific distribution, impenetrability of biological barrier, systemic toxicity, etc. In recent years, phage-based nanoplatforms have attracted increasing attention in tumor treatment for their regular structure, fantastic carrying property, high transduction efficiency and biosafety. Notably, therapeutic or targeting peptides can be expressed on the surface of the phages through phage display technology, enabling the phage vectors to possess multifunctions. As a result, the drug delivery efficiency on tumor will be vastly improved, thereby enhancing the therapeutic efficacy while reducing the side effects on normal tissues. Moreover, phages can overcome the hindrance of biofilm barrier to elicit antitumor effects, which exhibit great advantages compared with traditional synthetic drug delivery systems. Herein, this review not only summarizes the structure and biology of the phages, but also presents their potential as prominent nanoplatforms against tumor in different pathways to inspire the development of effective nanomedicine.

Differential effect of cancer-associated fibroblast-derived extracellular vesicles on cisplatin resistance in oral squamous cell carcinoma via miR-876-3p

Rationale: Platinum-based chemotherapy is commonly used for treating solid tumors, but drug resistance often limits its effectiveness. Cancer-associated fibroblast (CAF)-derived extracellular vesicle (EV), which carry various miRNAs, have been implicated in chemotherapy resistance. However, the molecular mechanism through which CAFs modulate cisplatin resistance in oral squamous cell carcinoma (OSCC) is not well understood. We employed two distinct primary CAF types with differential impacts on cancer progression: CAF-P, representing a more aggressive cancer-promoting category, and CAF-D, characterized by properties that moderately delay cancer progression. Consequently, we sought to investigate whether the two CAF types differentially affect cisplatin sensitivity and the underlying molecular mechanism. Methods: The secretion profile was examined by utilizing an antibody microarray with conditioned medium obtained from the co-culture of OSCC cells and two types of primary CAFs. The effect of CAF-dependent factors on cisplatin resistance was investigated by utilizing conditioned media (CM) and extracellular vesicle (EVs) derived from CAFs. The impacts of candidate genes were confirmed using gain- and loss-of-function analyses in spheroids and organoids, and a mouse xenograft. Lastly, we compared the expression pattern of the candidate genes in tissues from OSCC patients exhibiting different responses to cisplatin. Results: When OSCC cells were cultured with conditioned media (CM) from the two different CAF groups, cisplatin resistance increased only under CAF-P CM. OSCC cells specifically expressed insulin-like growth factor binding protein 3 (IGFBP3) after co-culture with CAF-D. Meanwhile, IGFBP3-knockdown OSCC cells acquired cisplatin resistance in CAF-D CM. IGFBP3 expression was promoted by GATA-binding protein 1 (GATA1), a transcription factor targeted by miR-876-3p, which was enriched only in CAF-P-derived EV. Treatment with CAF-P EV carrying miR-876-3p antagomir decreased cisplatin resistance compared to control miRNA-carrying CAF-P EV. On comparing the staining intensity between cisplatin-sensitive and -insensitive tissues from OSCC patients, there was a positive correlation between IGFBP3 and GATA1 expression and cisplatin sensitivity in OSCC tissues from patients. Conclusion: These results provide insights for overcoming cisplatin resistance, especially concerning EVs within the tumor microenvironment. Furthermore, it is anticipated that the expression levels of GATA1 and miR-876-3p, along with IGFBP3, could aid in the prediction of cisplatin resistance.

Application of cell-derived exosomes in the hematological malignancies therapy

Exosomes are small membrane vesicles of endocytic origin that are produced by both tumor and normal cells and can be found in physiological fluids like plasma and cell culture supernatants. They include cytokines, growth factors, proteins, lipids, RNAs, and metabolites and are important intercellular communication controllers in several disorders. According to a vast amount of research, exosomes could support or inhibit tumor start and diffusion in a variety of solid and hematological malignancies by paracrine signaling. Exosomes are crucial therapeutic agents for a variety of illnesses, such as cancer and autoimmune diseases. This review discusses the most current and encouraging findings from in vitro and experimental in vivo research, as well as the scant number of ongoing clinical trials, with a focus on the impact of exosomes in the treatment of malignancies. Exosomes have great promise as carriers of medications, antagonists, genes, and other therapeutic materials that can be incorporated into their core in a variety of ways. Exosomes can also alter the metabolism of cancer cells, alter the activity of immunologic effectors, and alter non-coding RNAs, all of which can alter the tumor microenvironment and turn it from a pro-tumor to an anti-tumor milieu. This subject is covered in the current review, which also looks at how exosomes contribute to the onset and progression of hematological malignancies, as well as their importance in diagnosing and treating these conditions.

Exosome nanovesicles as potential biomarkers and immune checkpoint signaling modulators in lung cancer microenvironment: recent advances and emerging concepts

Lung cancer remains the leading cause of cancer-related deaths globally, and the survival rate remains low despite advances in diagnosis and treatment. The progression of lung cancer is a multifaceted and dynamic phenomenon that encompasses interplays among cancerous cells and their microenvironment, which incorporates immune cells. Exosomes, which are small membrane-bound vesicles, are released by numerous cell types in normal and stressful situations to allow communication between cells. Tumor-derived exosomes (TEXs) possess diverse neo-antigens and cargoes such as proteins, RNA, and DNA and have a unique molecular makeup reflecting tumor genetic complexity. TEXs contain both immunosuppressive and immunostimulatory factors and may play a role in immunomodulation by influencing innate and adaptive immune components. Moreover, they transmit signals that contribute to the progression of lung cancer by promoting metastasis, epithelial-mesenchymal transition (EMT), angiogenesis, and immunosuppression. This makes them a valuable resource for investigating the immune environment of tumors, which could pave the way for the development of non-invasive biomarkers that could aid in the prognosis, diagnosis, and immunotherapy of lung cancer. While immune checkpoint inhibitor (ICI) immunotherapy has shown promising results in treating initial-stage cancers, most patients eventually develop adaptive resistance over time. Emerging evidence demonstrates that TEXs could serve as a prognostic biomarker for immunotherapeutic response and have a significant impact on both systemic immune suppression and tumor advancement. Therefore, understanding TEXs and their role in lung cancer tumorigenesis and their response to immunotherapies is an exciting research area and needs further investigation. This review highlights the role of TEXs as key contributors to the advancement of lung cancer and their clinical significance in lung immune-oncology, including their possible use as biomarkers for monitoring disease progression and prognosis, as well as emerging shreds of evidence regarding the possibility of using exosomes as targets to improve lung cancer therapy.

Biological function and research progress of N6-methyladenosine binding protein heterogeneous nuclear ribonucleoprotein A2B1 in human cancers

N6-methyladenosine (m6A) is the most prevalent internal modification found in both mRNA and lncRNA. It exerts reversible regulation over RNA function and affects RNA processing and metabolism in various diseases, especially tumors. The m6A binding protein, hnRNPA2B1, is extensively studied as a member of the heterogeneous nuclear ribonucleoprotein (hnRNP) protein family. It is frequently dysregulated and holds significant importance in multiple types of tumors. By recognizing m6A sites for variable splicing, maintaining RNA stability, and regulating translation and transport, hnRNPA2B1 plays a vital role in various aspects of tumor development, metabolism, and regulation of the immune microenvironment. In this review, we summarized the latest research on the functional roles and underlying molecular mechanisms of hnRNPA2B1. Moreover, we discussed its potential as a target for tumor therapy.

Roles of pulmonary telocytes in airway epithelia to benefit experimental acute lung injury through production of telocyte-driven mediators and exosomes

BACKGROUND

Telocytes (TCs) are experimentally evidenced as an alternative of cell therapies for organ tissue injury and repair. The aims of the present studies are to explore direct roles of TCs and the roles of TC-derived exosomes in support of experimental acute lung injury (ALI) in vivo or in vitro.

MATERIALS AND METHODS

The roles of TCs in experimental ALI were firstly estimated. Phosphoinositide 3-kinase (PI3K) p110δ and α/δ/β isoform inhibitors were used in study dynamic alterations of bio-behaviors, and in expression of functional factors of TCs per se and TC-co-cultured airway epithelial cells during the activation with lipopolysaccharide (LPS). TC-driven exosomes were furthermore characterized for intercellular communication by which activated or non-activated TCs interacted with epithelia.

RESULTS

Our results showed that TCs mainly prevented from lung tissue edema and hemorrhage and decreased the levels of VEGF-A and MMP9 induced by LPS. Treatment with CAL101 (PI3K p110δ inhibitor) and LY294002 (PI3Kα/δ/β inhibitor) could inhibit TC movement and differentiation and increase the number of dead TCs. The expression of Mtor, Hif1α, Vegf-a, or Mmp9 mRNA increased in TCs challenged with LPS, while Mtor, Hif1α, and Vegf-a even more increased after adding CAL101 or Mtor after adding LY. The rate of epithelial cell proliferation was higher in co-culture of human bronchial epithelial (HBE) and TCs than that in HBE alone under conditions with or without LPS challenge or when cells were treated with LPS and CAL101 or LY294002. The levels of mTOR, HIF1α, or VEGF-A significantly increased in mono-cultured or co-cultured cells, challenged with LPS as compared with those with vehicle. LPS-pretreated TC-derived exosomes upregulated the expression of AKT, p-AKT, HIF1α, and VEGF-A protein of HBE.

CONCLUSION

The present study demonstrated that intraperitoneal administration of TCs ameliorated the severity of lung tissue edema accompanied by elevated expression of VEGF-A. TCs could nourish airway epithelial cells through nutrients produced from TCs, increasing epithelial cell proliferation, and differentiation as well as cell sensitivity to LPS challenge and PI3K p110δ and α/δ/β inhibitors, partially through exosomes released from TCs.

Breast cancer heterogeneity and its implication in personalized precision therapy

Breast cancer heterogeneity determines cancer progression, treatment effects, and prognosis. However, the precise mechanism for this heterogeneity remains unknown owing to its complexity. Here, we summarize the origins of breast cancer heterogeneity and its influence on disease progression, recurrence, and therapeutic resistance. We review the possible mechanisms of heterogeneity and the research methods used to analyze it. We also highlight the importance of cell interactions for the origins of breast cancer heterogeneity, which can be further categorized into cooperative and competitive interactions. Finally, we provide new insights into precise individual treatments based on heterogeneity.

Proteomics Analysis of Plasma-Derived Exosomes Unveils the Aberrant Complement and Coagulation Cascades in Dermatomyositis/Polymyositis

Dermatomyositis and polymyositis (DM/PM) are systemic autoimmune diseases characterized by proximal muscle weakness. The underlying pathogenetic mechanism of this disease remains under-researched. Here, using proteomics analysis, a great overlap of differentially expressed plasma exosomal proteins involved in the complement and coagulation cascade pathway, including FGA, FGB, FGG, C1QB, C1QC, and VWF, was identified in DM/PM patients versus healthy controls. Correlation analysis showed that the expression levels of complement-associated proteins (C1QB and C1QC) correlated positively with CRP, ESR, and platelet count. ROC curve analysis demonstrated that complement and coagulation cascade-associated proteins could be strong predictors for DM/PM. In addition, we also identified several other proteins that were differentially expressed in DM and PM. The selected candidate proteins were further validated by parallel reaction monitoring (PRM) and enzyme-linked immunosorbent assay (ELISA). Together, our findings indicate that these exosome-derived proteins might participate in microvascular damage in DM/PM through the activation of the complement and coagulation cascade pathway and function as biomarkers for the clinical diagnosis of DM/PM.

In situ detection of exosomal RNAs for cancer diagnosis

Exosomes are considered as biomarkers reflecting the physiological state of the human body. Studies have revealed that the expression levels of specific exosomal RNAs are closely associated with certain cancers. Thus, detection of exosomal RNA offers a new avenue for liquid biopsy of cancers. Many exosomal RNA detection methods based on various principles have been developed, and most of the methods detect the extracted RNAs after lysing exosomes. Besides complex and time-consuming extraction steps, a major drawback of this approach is the degradation of the extracted RNAs in the absence of plasma membrane and cytosol. In addition, there is considerable loss of RNAs during their extraction. In situ detection of exosomal RNAs can avoid these drawbacks, thus allowing higher diagnostic reliability. In this paper, in situ detection of exosomal RNAs was systematically reviewed from the perspectives of detection methods, transport methods of the probe systems, probe structures, signal amplification strategies, and involved functional materials. Furthermore, the limitations and possible improvements of the current in situ detection methods for exosomal RNAs towards the clinical diagnostic application are discussed. This review aims to provide a valuable reference for the development of in situ exosomal RNA detection strategies for non-invasive diagnosis of cancers. STATEMENT OF SIGNIFICANCE: Certain RNAs have been identified as valuable biomarkers for some cancers, and sensitive detection of cancer-related RNAs is expected to achieve better diagnostic efficacy. Currently, the detection of exosomal RNAs is receiving increasing attention due to their high stability and significant concentration differences between patients and healthy individuals. In situ detection of exosomal RNAs has greater diagnostic reliability due to the avoidance of RNA degradation and loss. However, this mode is still limited by some factors such as detection methods, transport methods of the probe systems, probe structures, signal amplification strategies, etc. This review focuses on the progress of in situ detection of exosomal RNAs and aims to promote the development of this field.

Exosomes in Genitourinary Cancers: Emerging Mediators of Drug Resistance and Promising Biomarkers

Drug resistance presents a major obstacle in the treatment of genitourinary cancers. Exosomes as the medium of intercellular communication serve important biological functions and play essential roles in pathological processes, including drug response. Through the transfer of bioactive cargoes, exosomes can modulate drug resistance via multiple mechanisms. This review attempts to elucidate the mechanisms of exosomal cargoes with reference to tumor drug resistance, their role in genitourinary cancers, and their potential clinical applications as candidate biomarkers in liquid biopsy.

Exosomal miRNAs-a diagnostic biomarker acting as a guiding light in the diagnosis of prostate cancer

Prostate cancer, one of the major causes of mortality globally is regarded as the second leading cause of mortality among men. It is known to affect the stromal cells surrounding it. Through the use of exosomes, the affected stromal cells can promote the growth and spread of the cancer. Exosomes are known to play a role not only in the development and progression of cancer but also contribute to the drug-resistance character of cancer cells. Recently, the discovery of the small non-coding RNAs or miRNA has attracted attention of cancer researchers as they can regulate the expression of different genes. Therefore, exosomal miRNA can be used as a novel and reliable biomarker for the diagnosis and treatment of prostate cancer. In addition, exosomal miRNAs can also be used as a potential treatment for prostate cancer. The goal of this review is to provide a comprehensive analysis of the current knowledge about the role of exosomal miRNAs in the treatment of patients with prostate cancer and their potential role in monitoring the disease.

Drug Resistance: The Role of Exosomal miRNA in the Microenvironment of Hematopoietic Tumors

Extracellular vesicles (EVs), including exosomes, have an important role thanks to their ability to communicate and exchange information between tumor cells and the tumor microenvironment (TME), and have also been associated with communicating anti-cancer drug resistance (DR). The increase in proliferation of cancer cells alters oxygen levels, which causes hypoxia and results in a release of exosomes by the cancer cells. In this review, the results of studies examining the role of exosomal miRNA in DR, and their mechanism, are discussed in detail in hematological tumors: leukemia, lymphoma, and multiple myeloma. In conclusion, we underline the exosome's function as a possible drug delivery vehicle by understanding its cargo. Engineered exosomes can be used to be more specific for personalized therapy.

The importance of being CAFs (in cancer resistance to targeted therapies)

In the last two decades, clinical oncology has been revolutionized by the advent of targeted drugs. However, the efficacy of these therapies is significantly limited by primary and acquired resistance, that relies not only on cell-autonomous mechanisms but also on tumor microenvironment cues. Cancer-associated fibroblasts (CAFs) are extremely plastic cells of the tumor microenvironment. They not only produce extracellular matrix components that build up the structure of tumor stroma, but they also release growth factors, chemokines, exosomes, and metabolites that affect all tumor properties, including response to drug treatment. The contribution of CAFs to tumor progression has been deeply investigated and reviewed in several works. However, their role in resistance to anticancer therapies, and in particular to molecular therapies, has been largely overlooked. This review specifically dissects the role of CAFs in driving resistance to targeted therapies and discusses novel CAF targeted therapeutic strategies to improve patient survival.

Nanomedicines in oral cancer: inspiration comes from extracellular vesicles and biomimetic nanoparticles

Oral cancer is a common life-threatening malignancy having high mortality and morbidity rates. During the treatment process, individuals unavoidably experience severe side effects. It is essential to develop safer and more effective strategies. Currently, extracellular vesicles (EVs) and biomimetic nanoparticles are nanomedicines with long-term blood circulation and lower off-target toxicity that orchestrate immune responses and accumulate specifically in tumor sites. EVs create a synergetic effect by encapsulating drugs and collaborating with naturally loaded elements in the EVs. Biomimetic nanoparticles retain the characteristic features of the synthetic nanocarriers and inherit the intrinsic cell membrane functionalities. This review outlines the properties, applications, challenges, pros and cons of EVs and biomimetic nanoparticles, providing novel perspectives on oral cancer.

The history of small extracellular vesicles and their implication in cancer drug resistance

Small extracellular vesicles (EVs) in the last 20 years are demonstrated to possess promising properties as potential new drug delivery systems, biomarkers, and therapeutic targets. Moreover, EVs are described to be involved in the most important steps of tumor development and progression including drug resistance. The acquired or intrinsic capacity of cancer cells to resist chemotherapies is one of the greatest obstacles to overcome to improve the prognosis of many patients. EVs are involved in this mechanism by exporting the drugs outside the cells and transferring the drug efflux pumps and miRNAs in recipient cells, in turn inducing drug resistance. In this mini-review, the main mechanisms by which EVs are involved in drug resistance are described, giving a rapid and clear overview of the field to the readers.

Exosomes at the crossroad between therapeutic targets and therapy resistance in head and neck squamous cell carcinoma

Head and neck squamous cell carcinomas (HNSCCs) are aggressive and clinically challenging tumours that require a multidisciplinary management approach. Despite significant therapy improvements, HNSCC patients have a poor prognosis with a 5-year survival rate of about 65%. As recently recognised key players in cancer, exosomes are extracellular vesicles (EVs) with a diameter of nearly 50-120 nm which transport information from one cell to another. Exosomes are actively involved in various aspects of tumour initiation, development, metastasis, immune regulation, therapy resistance, and therapeutic applications. However, current knowledge of the role of exosomes in the pathophysiological processes of HNSCC is still in its infancy, and additional studies are needed. In this review, we summarise and discuss the relevance of exosomes in mediating local immunosuppression and therapy resistance of HNSCC. We also review the most recent studies that have explored the therapeutic potential of exosomes as cancer vaccines, drug carriers or tools to reverse the drug resistance of HNSCC.

Extracellular Vesicles and Circulating Tumour Cells - complementary liquid biopsies or standalone concepts?

Liquid biopsies do promise a lot, but are they keeping it? In the past decade, additional novel biomarkers qualified to be called like that, of which, some took necessary hurdles resulting in FDA approval and clinical use. Some others are since a while around, well known and were once regarded to be a game changer in cancer diagnosis or cancer screening. But, during their clinical use limitations were observed from statistical significance and questions raised regarding their robustness, that eventually led to be dropped from associated clinical guidelines for certain applications including cancer diagnosis. The purpose of this review isn't to give a broad overview of all current liquid biopsy as biomarkers, weight them and promise a brighter future in cancer prevention, but rather to take a deeper look on two of those who do qualify to be called liquid biopsies now or then. These two are probably of greatest interest conceptually and methodically, and likely have the highest chances to be in clinical use soon, with a portfolio extension over their original conceptual usage. We aim to dig deeper beyond cancer diagnosis or cancer screening. Actually, we aim to review in depth extracellular vesicles (EVs) and compare with circulating tumour cells (CTCs). The latter methodology is partially FDA approved and in clinical use. We will lay out similarities as taking advantage of surface antigens on EVs and CTCs in case of characterization and quantification. But drawing readers' attention to downstream application based on capture/isolation methodology and simply on their overall nature, here apparently being living material eventually recoverable as CTCs are vs. dead material with transient effects on recipient cell as in case of EVs. All this we try to bring in perspective, compare and conclude towards which future direction we are aiming for, or should aim for. Do we announce a winner between CTCs vs EVs? No, but we provide good reasons to intensify research on them.

The Essential Role of FoxO1 in the Regulation of Macrophage Function

Macrophages are widely distributed in various tissues and organs. They not only participate in the regulation of innate and adaptive immune response, but also play an important role in tissue homeostasis. Dysregulation of macrophage function is closely related to the initiation, development and prognosis of multiple diseases, including infection and tumorigenesis. Forkhead box transcription factor O1 (FoxO1) is an important member among the forkhead box transcription factor family. Through directly binding to the promoter regions of downstream target genes, FoxO1 is implicated in cell proliferation, apoptosis, metabolic activities and other biological processes. In this review, we summarized the regulatory role of FoxO1 in macrophage phagocytosis, migration, differentiation and inflammatory activation. We also emphasized that macrophage reciprocally modulated FoxO1 activity via a post-translational modification (PTM) dominant manner.

A genomic instability-related lncRNA model for predicting prognosis and immune checkpoint inhibitor efficacy in breast cancer

Breast cancer has overtaken lung cancer as the most frequently diagnosed cancer type and is the leading cause of death for women worldwide. It has been demonstrated in published studies that long non-coding RNAs (lncRNAs) involved in genomic stability are closely associated with the progression of breast cancer, and remarkably, genomic stability has been shown to predict the response to immune checkpoint inhibitors (ICIs) in cancer therapy, especially colorectal cancer. Therefore, it is of interest to explore somatic mutator-derived lncRNAs in predicting the prognosis and ICI efficacy in breast cancer patients. In this study, the lncRNA expression data and somatic mutation data of breast cancer patients from The Cancer Genome Atlas (TCGA) were downloaded and analyzed thoroughly. Univariate and multivariate Cox proportional hazards analyses were used to generate the genomic instability-related lncRNAs in a training set, which was subsequently used to analyze a testing set and combination of the two sets. The qRT-PCR was conducted in both normal mammary and breast cancer cell lines. Furthermore, the Kaplan–Meier and receiver operating characteristic (ROC) curves were applied to validate the predictive effect in the three sets. Finally, the Cell-type Identification by Estimating Relative Subsets of RNA Transcripts (CIBERSORT) algorithm was used to evaluate the association between genomic instability-related lncRNAs and immune checkpoints. As a result, a six-genomic instability-related lncRNA signature (U62317.4, MAPT-AS1, AC115837.2, EGOT, SEMA3B-AS1, and HOTAIR) was identified as the independent prognostic risk model for breast cancer patients. Compared with the normal mammary cells, the qRT-PCR showed that HOTAIR was upregulated while MAPT-AS1, EGOT, and SEMA3B-AS1 were downregulated in breast cancer cells. The areas under the ROC curves at 3 and 5 years were 0.711 and 0.723, respectively. Moreover, the patients classified in the high-risk group by the prognostic model had abundant negative immune checkpoint molecules. In summary, this study suggested that the prognostic model comprising six genomic instability-related lncRNAs may provide survival prediction. It is necessary to identify patients who are suitable for ICIs to avoid severe immune-related adverse effects, especially autoimmune diseases. This model may predict the ICI efficacy, facilitating the identification of patients who may benefit from ICIs.

Microfluidics for detection of exosomes and microRNAs in cancer: State of the art

Exosomes are small extracellular vesicles with sizes ranging from 30-150 nanometers that contain proteins, lipids, mRNAs, microRNAs, and double-stranded DNA derived from the cells of origin. Exosomes can be taken up by target cells, acting as a means of cell-to-cell communication. The discovery of these vesicles in body fluids and their participation in cell communication has led to major breakthroughs in diagnosis, prognosis, and treatment of several conditions (e.g., cancer). However, conventional isolation and evaluation of exosomes and their microRNA content suffers from high cost, lengthy processes, difficult standardization, low purity, and poor yield. The emergence of microfluidics devices with increased efficiency in sieving, trapping, and immunological separation of small volumes could provide improved detection and monitoring of exosomes involved in cancer. Microfluidics techniques hold promise for advances in development of diagnostic and prognostic devices. This review covers ongoing research on microfluidics devices for detection of microRNAs and exosomes as biomarkers and their translation to point-of-care and clinical applications.

Exosome-Mediated Response to Cancer Therapy: Modulation of Epigenetic Machinery

Exosomes, the extracellular vesicles produced in the endosomal compartments, facilitate the transportation of proteins as well as nucleic acids. Epigenetic modifications are now considered important for fine-tuning the response of cancer cells to various therapies, and the acquired resistance against targeted therapies often involves dysregulated epigenetic modifications. Depending on the constitution of their cargo, exosomes can affect several epigenetic events, thus impacting post-transcriptional regulations. Thus, a role of exosomes as facilitators of epigenetic modifications has come under increased scrutiny in recent years. Exosomes can deliver methyltransferases to recipient cells and, more importantly, non-coding RNAs, particularly microRNAs (miRNAs), represent an important exosome cargo that can affect the expression of several oncogenes and tumor suppressors, with a resulting impact on cancer therapy resistance. Exosomes often harbor other non-coding RNAs, such as long non-coding RNAs and circular RNAs that support resistance. The exosome-mediated transfer of all this cargo between cancer cells and their surrounding cells, especially tumor-associated macrophages and cancer-associated fibroblasts, has a profound effect on the sensitivity of cancer cells to several chemotherapeutics. This review focuses on the exosome-induced modulation of epigenetic events with resulting impact on sensitivity of cancer cells to various therapies, such as, tamoxifen, cisplatin, gemcitabine and tyrosine kinase inhibitors. A better understanding of the mechanisms by which exosomes can modulate response to therapy in cancer cells is critical for the development of novel therapeutic strategies to target cancer drug resistance.

Emerging roles of exosome-derived biomarkers in cancer theranostics: messages from novel protein targets

Effective biomarkers that guide therapeutics with limited adverse effects, have emerged as attractive research topics in cancer diagnosis and treatment. Cancer-derived exosomes, a type of extracellular vesicles representing molecular signatures of cells of origin, could serve as stable reservoirs for potential biomarkers (i.e., proteins, nucleic acids) in non-invasive cancer diagnosis and prognosis. In this review, the physiological and pathological roles of exosomes and their protein components in facilitating tumorigenesis are highlighted. Exosomes carrying proteins can participate in tumor development and progression through multiple signaling pathways, including EMT, invasion and metastasis. Meanwhile, the practical applications of exosomal proteins in detecting and monitoring several solid-tumor cancers (including lung, breast, pancreatic, colorectal and prostate cancers) were also summarized. More clinically relevant, exosomal proteins play pivotal roles in transmitting oncogenic potential or resistance to therapies in recipient cells, which might further support therapeutic strategy determinations.

Vitamin D Reverts the Exosome-Mediated Transfer of Cancer Resistance to the mTOR Inhibitor Everolimus in Hepatocellular Carcinoma

Several multi-kinase inhibitors were widely tested as potential first-line or second-line therapy in patients with advanced hepatocellular carcinoma (HCC). However, acquired drug resistance limits their clinical efficacy. Exosomes are microvesicles secreted by tumor and stromal cells that participate in many biological processes, including drug resistance. The current study evaluated the capability of exosomes derived from everolimus (EVE)-resistant HCC cells in inducing drug resistance in parental human HCC cells and the effect of 1,25(OH)₂Vitamin D (VitD) treatment in restoring EVE sensitivity. The internalization of exosomes from EVE-resistant (EveR) cells into parental cells conferred the transmission of aggressive phenotype by promoting the transition of epithelial-to-mesenchymal phenotype, as demonstrated by immunofluorescence, and the acquisition of EVE resistance, as demonstrated by cell proliferation and colony formation assays. Moreover, the internalization of exosomes from EveR into parental cells induced deregulation of the mTOR pathway mainly by triggering the activation of the serine/threonine protein kinase Akt, involved in the cellular survival pathway, as demonstrated by Western blot analysis. Interestingly, the treatment with VitD prevented exosome-induced EVE resistance in HCC cells, significantly inhibiting cell proliferation but also partially reducing colony and size number when combined with EVE compared with control. In conclusion, the results of the current study demonstrated that exosomes derived from EveR cells could induce EVE resistance in EVE-sensitive HCC cells and that VitD can revert the exosome-induced EVE resistance by resensitizing to EVE treatment.

Extracellular Vesicles and Cell Pathways Involved in Cancer Chemoresistance

Chemoresistance is a pharmacological condition that allows transformed cells to maintain their proliferative phenotype in the presence of administered anticancer drugs. Recently, extracellular vesicles, including exosomes, have been identified as additional players responsible for the chemoresistance of cancer cells. These are nanovesicles that are released by almost all cell types in both physiological and pathological conditions and contain proteins and nucleic acids as molecular cargo. Extracellular vesicles released in the bloodstream reach recipient cells and confer them novel metabolic properties. Exosomes can foster chemoresistance by promoting prosurvival and antiapoptotic pathways, affecting cancer stem cells and immunotherapies, and stimulating drug efflux. In this context, a crucial role is played by membrane transporters belonging to ABC, SLC, and P-type pump families. These proteins are fundamental in cell metabolism and drug transport in either physiological or pathological conditions. In this review, different roles of extracellular vesicles in drug resistance of cancer cells will be explored.

Biological Characteristics and Clinical Significance of Soluble PD-1/PD-L1 and Exosomal PD-L1 in Cancer

The immune checkpoint pathway consisting of the cell membrane-bound molecule programmed death protein 1 (PD-1) and its ligand PD-L1 has been found to mediate negative regulatory signals that effectively inhibit T-cell proliferation and function and impair antitumor immune responses. Considerable evidence suggests that the PD-1/PD-L1 pathway is responsible for tumor immune tolerance and immune escape. Blockage of this pathway has been found to reverse T lymphocyte depletion and restore antitumor immunity. Antagonists targeting this pathway have shown significant clinical activity in specific cancer types. Although originally identified as membrane-type molecules, several other forms of PD-1/PD-L1 have been detected in the blood of cancer patients, including soluble PD-1/PD-L1 (sPD-1/sPD-L1) and exosomal PD-L1 (exoPD-L1), increasing the composition and functional complications of the PD-1/PD-L1 signaling pathway. For example, sPD-1 has been shown to block the PD-1/PD-L immunosuppressive pathway by binding to PD-L1 and PD-L2, whereas the role of sPD-L1 and its mechanism of action in cancer remain unclear. In addition, many studies have investigated the roles of exoPD-L1 in immunosuppression, as a biomarker for tumor progression and as a predictive biomarker for response to immunotherapy. This review describes the molecular mechanisms underlying the generation of sPD-1/sPD-L1 and exoPD-L1, along with their biological activities and methods of detection. In addition, this review discusses the clinical importance of sPD-1/sPD-L1 and exoPD-L1 in cancer, including their predictive and prognostic roles and the effects of treatments that target these molecules.

Extracellular vesicles in pharmacology: Novel approaches in diagnostics and therapy

Exosomes are nano-sized lipid vesicles that are produced by all eukaryotic cells, and they typically range in size from 30 to 150 nm. Exosomes were discovered almost 40 years ago; however, the last two decades have attracted considerable attention due to exosomes' inherent abilities to shuttle nucleic acids, lipids and proteins between cells, along with their natural affinity to exosome target cells. From a pharmaceutical perspective, exosomes are regarded as naturally produced nanoparticle drug delivery vehicles. The application of exosomes as a means of drug delivery offers critical advantages compared to other nanoparticulate drug delivery systems, such as liposomes and polymeric nanoparticles. These advantages are due to the exosomes' intrinsic features, such as low immunogenicity, biocompatibility, stability, and their ability to overcome biological barriers. Herein, we outline the structure and origin of exosomes, as well as their biological functions. We also touch upon recent advances in exosome labeling, imaging and drug loading. Finally, we discuss exosomes in targeted drug delivery and clinical trial development.

Formation, contents, functions of exosomes and their potential in lung cancer diagnostics and therapeutics

Lung cancer is the leading cause of cancer-related death worldwide due to diagnosis in the advanced stage and drug resistance in the subsequent treatments. Development of novel diagnostic and therapeutic methods is urged to improve the disease outcome. Exosomes are nano-sized vehicles which transport different types of biomolecules intercellularly, including DNA, RNA and proteins, and are implicated in cross-talk between cells and their surrounding microenvironment. Tumor-derived exosomes (TEXs) have been revealed to strongly influence the tumor microenvironment, antitumor immunoregulatory activities, tumor progression and metastasis. Potential of TEXs as biomarkers for lung cancer diagnosis, prognosis and treatment prediction is supported by numerous studies. Moreover, exosomes have been proposed to be promising drug carriers. Here, we review the mechanisms of exosomal formation and uptake, the functions of exosomes in carcinogenesis, and potential clinical utility of exosomes as biomarkers, tumor vaccine and drug delivery vehicles in the diagnosis and therapeutics of lung cancer.

Roles of Microvesicles in Tumor Progression and Clinical Applications

Microvesicles are extracellular vesicles with diameter ranging from 100 to 1000 nm that are secreted by tumor cells or other cells in the tumor microenvironment. A growing number of studies demonstrate that tumor-derived microvesicles are involved in tumor initiation and progression, as well as drug resistance. In addition, tumor-derived microvesicles carry a variety of immunogenic molecules and inhibit tumor response to immunotherapy; therefore, they can be exploited for use in tumor vaccines. Moreover, because of their high stability, tumor-derived microvesicles extracted from body fluids can be used as biomarkers for cancer diagnosis or assessment of prognosis. Tumor-derived microvesicles can also be deployed to reverse drug resistance of tumor regenerative cells, or to deliver chemotherapeutic drugs and oncolytic adenovirus for the treatment of cancer patients. This review summarizes the general characteristics of tumor-derived microvesicles, focusing on their biological characteristics, their involvement in tumor progression, and their clinical applications.