Adipose-derived exosomes deliver miR-23a/b to regulate tumor growth in hepatocellular cancer by targeting the VHL/HIF axis

The interplay between the tumor microenvironment and tumor-derived small extracellular vesicles in cancer development and therapeutic response

The tumor microenvironment (TME) plays an essential role in tumor cell survival by profoundly influencing their proliferation, metastasis, immune evasion, and resistance to treatment. Extracellular vesicles (EVs) are small particles released by all cell types and often reflect the state of their parental cells and modulate other cells' functions through the various cargo they transport. Tumor-derived small EVs (TDSEVs) can transport specific proteins, nucleic acids and lipids tailored to propagate tumor signals and establish a favorable TME. Thus, the TME's biological characteristics can affect TDSEV heterogeneity, and this interplay can amplify tumor growth, dissemination, and resistance to therapy. This review discusses the interplay between TME and TDSEVs based on their biological characteristics and summarizes strategies for targeting cancer cells. Additionally, it reviews the current issues and challenges in this field to offer fresh insights into comprehending tumor development mechanisms and exploring innovative clinical applications.

Interplay among extracellular vesicles, cancer stemness and immune regulation in driving hepatocellular carcinoma progression

The intricate interplay among extracellular vesicles, cancer stemness properties, and the immune system significantly impacts hepatocellular carcinoma (HCC) progression, treatment response, and patient prognosis. Extracellular vesicles (EVs), which are membrane-bound structures, play a pivotal role in conveying proteins, lipids, and nucleic acids between cells, thereby serving as essential mediators of intercellular communication. Since a lot of current research focuses on small extracellular vesicles (sEVs), with diameters ranging from 30 nm to 200 nm, this review emphasizes the role of sEVs in the context of interactions between HCC stemness-bearing cells and the immune cells. sEVs offer promising opportunities for the clinical application of innovative diagnostic and prognostic biomarkers in HCC. By specifically targeting sEVs, novel therapeutics aimed at cancer stemness can be developed. Ongoing investigations into the roles of sEVs in cancer stemness and immune regulation in HCC will broaden our understanding and ultimately pave the way for groundbreaking therapeutic interventions.

Regulatory role of exosome-derived miRNAs and other contents in adipogenesis

Intramuscular fat (IMF) content significantly impacts meat quality. influenced by complex interactions between skeletal muscle cells and adipocytes. Adipogenesis plays a pivotal role in IMF formation. Exosomes, extracellular membranous nanovesicles, facilitate intercellular communication by transporting proteins, nucleic acids (DNA and RNA), and other biomolecules into target cells, thereby modulating cellular behaviors. Recent studies have linked exosome-derived microRNAs (miRNAs) and other cargo to adipogenic processes. Various cell types, including skeletal muscle cells, interact with adipocytes via exosome secretion and uptake. Exosomes entering adipocytes regulate adipogenesis by modulating key signaling pathways, thereby influencing the extent and distribution of IMF deposition. This review comprehensively explores the origin, formation, and mechanisms of exosome action, along with current research and their applications in adipogenesis. Emphasis is placed on exosome-mediated regulation of miRNAs, non-coding RNAs (ncRNAs), proteins, lipids, and other biomolecules during adipogenesis. Leveraging exosomal contents for genetic breeding and treating obesity-related disorders is discussed. Insights gathered contribute to advancing understanding and potential therapeutic applications of exosome-regulated adipogenesis mechanisms.

Emerging role of exosomal microRNA in liver cancer in the era of precision medicine; potential and challenges

Exosomal microRNAs (miRNAs) have great potential in the fight against hepatocellular carcinoma (HCC), the fourth most common cause of cancer-related death worldwide. In this study, we explored the various applications of these small molecules while analyzing their complex roles in tumor development, metastasis, and changes in the tumor microenvironment. We also discussed the complex interactions that exist between exosomal miRNAs and other non-coding RNAs such as circular RNAs, and show how these interactions coordinate important biochemical pathways that propel the development of HCC. The possibility of targeting exosomal miRNAs for therapeutic intervention is paramount, even beyond their mechanistic significance. We also highlighted their growing potential as cutting-edge biomarkers that could lead to tailored treatment plans by enabling early identification, precise prognosis, and real-time treatment response monitoring. This thorough analysis revealed an intricate network of exosomal miRNAs lead to HCC progression. Finally, strategies for purification and isolation of exosomes and advanced biosensing techniques for detection of exosomal miRNAs are also discussed. Overall, this comprehensive review sheds light on the complex web of exosomal miRNAs in HCC, offering valuable insights for future advancements in diagnosis, prognosis, and ultimately, improved outcomes for patients battling this deadly disease.

Mitochondria-Derived Vesicles, Sterile Inflammation, and Pyroptosis in Liver Cancer: Partners in Crime or Innocent Bystanders?

Alterations in cellular signaling, chronic inflammation, and tissue remodeling contribute to hepatocellular carcinoma (HCC) development. The release of damage-associated molecular patterns (DAMPs) upon tissue injury and the ensuing sterile inflammation have also been attributed a role in HCC pathogenesis. Cargoes of extracellular vesicles (EVs) and/or EVs themselves have been listed among circulating DAMPs but only partially investigated in HCC. Mitochondria-derived vesicles (MDVs), a subpopulation of EVs, are another missing link in the comprehension of the molecular mechanisms underlying the onset and progression of HCC biology. EVs have been involved in HCC growth, dissemination, angiogenesis, and immunosurveillance escape. The contribution of MDVs to these processes is presently unclear. Pyroptosis triggers systemic inflammation through caspase-dependent apoptotic cell death and is implicated in tumor immunity. The analysis of this process, together with MDV characterization, may help capture the relationship among HCC development, mitochondrial quality control, and inflammation. The combination of immune checkpoint inhibitors (i.e., atezolizumab and bevacizumab) has been approved as a synergistic first-line systemic treatment for unresectable or advanced HCC. The lack of biomarkers that may allow prediction of treatment response and, therefore, patient selection, is a major unmet need. Herein, we overview the molecular mechanisms linking mitochondrial dysfunction, inflammation, and pyroptosis, and discuss how immunotherapy targets, at least partly, these routes.

The role of novel adipokines and adipose-derived extracellular vesicles (ADEVs): Connections and interactions in liver diseases

Adipose tissues (AT) are an important endocrine organ that secretes various functional adipokines, peptides, non-coding RNAs, and acts on AT themselves or other distant tissues or organs through autocrine, paracrine, or endocrine manners. An accumulating body of evidence has suggested that many adipokines play an important role in liver metabolism. Besides the traditional adipokines such as adiponectin and leptin, many novel adipokines have recently been identified to have regulatory effects on the liver. Additionally, AT can produce extracellular vesicles (EVs) that act on peripheral tissues. However, under pathological conditions, such as obesity and diabetes, dysregulation of adipokines is associated with functional changes in AT, which may cause liver diseases. In this review, we focus on the newly discovered adipokines and EVs secreted by AT and highlight their actions on the liver under the context of obesity, nonalcoholic fatty liver diseases (NAFLD), and some other liver diseases. Clarifying the action of adipokines and adipose tissue-derived EVs on the liver would help to identify novel therapeutic targets or biomarkers for metabolic diseases.

Extracellular vesicles and cancer stemness in hepatocellular carcinoma - is there a link?

Hepatocellular carcinoma (HCC) is a highly aggressive malignancy, with high recurrence rates and notorious resistance to conventional chemotherapy. Cancer stemness refers to the stem-cell-like phenotype of cancer cells and has been recognized to play important roles in different aspects of hepatocarcinogenesis. Small extracellular vesicles (sEVs) are small membranous particles secreted by cells that can transfer bioactive molecules, such as nucleic acids, proteins, lipids, and metabolites, to neighboring or distant cells. Recent studies have highlighted the role of sEVs in modulating different aspects of the cancer stemness properties of HCC. Furthermore, sEVs derived from diverse cellular sources, such as cancer cells, stromal cells, and immune cells, contribute to the maintenance of the cancer stemness phenotype in HCC. Through cargo transfer, specific signaling pathways are activated within the recipient cells, thus promoting the stemness properties. Additionally, sEVs can govern the secretion of growth factors from non-cancer cells to further maintain their stemness features. Clinically, plasma sEVs may hold promise as potential biomarkers for HCC diagnosis and treatment prediction. Understanding the underlying mechanisms by which sEVs promote cancer stemness in HCC is crucial, as targeting sEV-mediated communication may offer novel strategies in treatment and improve patient outcome.

Epigenetic modifications in obesity-associated diseases

The global prevalence of obesity has reached epidemic levels, significantly elevating the susceptibility to various cardiometabolic conditions and certain types of cancer. In addition to causing metabolic abnormalities such as insulin resistance (IR), elevated blood glucose and lipids, and ectopic fat deposition, obesity can also damage pancreatic islet cells, endothelial cells, and cardiomyocytes through chronic inflammation, and even promote the development of a microenvironment conducive to cancer initiation. Improper dietary habits and lack of physical exercise are important behavioral factors that increase the risk of obesity, which can affect gene expression through epigenetic modifications. Epigenetic alterations can occur in early stage of obesity, some of which are reversible, while others persist over time and lead to obesity-related complications. Therefore, the dynamic adjustability of epigenetic modifications can be leveraged to reverse the development of obesity-associated diseases through behavioral interventions, drugs, and bariatric surgery. This review provides a comprehensive summary of the impact of epigenetic regulation on the initiation and development of obesity-associated cancers, type 2 diabetes, and cardiovascular diseases, establishing a theoretical basis for prevention, diagnosis, and treatment of these conditions.

Obese Mouse Fat Cell-derived Extracellular Vesicles Transport miR-99a-5p to Mitigate the Proliferation and Migration of Non-small Cell Lung Cancer Cells

OBJECTIVE

Fat cells-derived extracellular vesicles (FC-EVs) play a role in regulating the tumor microenvironment in cancers by transporting RNAs. MicroRNAs (miRNAs) are vital regulators of cancer development. This study was conducted to explore the role of FC-EVs in the proliferation and migration of non-small cell lung cancer (NSCLC) cells, providing targets for NSCLC treatment.

METHODS

The obese mouse model was established via high-fat diet (HFD), followed by separation and characterization of FC-EVs (HFD-EVs). The levels of miR-99a-5p, precursor-miR-99a-5p, and heparan sulfate-glucosamine 3-sulfotransferase 3B1 (HS3ST3B1) were measured by RT-qPCR or Western blot assay. Cell proliferation and migration were evaluated by 3-(4, 5-dimethylthiazol- 2-yl)-2, 5-diphenyltetrazolium bromide and wound healing assays. The expression of Cy3-labeled miR-99a-5p in A549 cells (one NSCLC cell line) was observed via confocal microscopy. The binding of miR-99a-5p to HS3ST3B1 was analyzed by the dual luciferase assay. Rescue experiments were performed to confirm the role of HS3ST3B1 in NSCLC cells.

RESULTS

miR-99a-5p was upregulated in adipose tissues, FCs, and HFD-EVs. HFD-EVs mitigated the proliferation and migration of NSCLC cells. HFD-EVs transported miR-99a-5p into A549 cells, which upregulated miR-99a-5p expression and inhibited HS3ST3B1 expression in A549 cells. HS3ST3B1 overexpression reversed the inhibition of HFD-EVs on the proliferation and migration of NSCLC cells.

CONCLUSION

HFD-EVs transported miR-99a-5p into NSCLC cells and inhibited HS3ST3B1, thereby inhibiting proliferation and migration of NSCLC cells.

Adipocyte-derived exosomes promote the progression of triple-negative breast cancer through circCRIM1-dependent OGA activation

Triple-negative breast cancer (TNBC) has an escalating morbidity and a dismal prognosis. Obesity has been reported to be strongly linked to adverse TNBC outcomes. Exosomes (Exos) transport RNA and proteins between cells and serve as intermediaries for cell-to-cell communication. Accumulated evidence suggests that adipose-secreted circular RNAs (circRNAs) can modulate protein glycosylation in TNBC to facilitate tumor cell outgrowth. Herein, exo-circCRIM1 expression was found to be elevated in TNBC patients with a high body fat percentage. Functional experiments demonstrated that by inhibiting miR-503-5p, exo-circCRIM1 enhanced TNBC evolution and metastasis while activating glycosylation hydrolase OGA. Furthermore, OGA negatively regulates FBP1 by decreasing its protein stability. Moreover, the levels of OGA and FBP1 were positively related to the infiltration level of some immune cells in TNBC. These findings indicate that exo-cirCRIM1 secreted by adipocytes contributes to TNBC progression by inhibiting miR-503-5p and activating the OGA/FBP1 signaling pathway. The findings reveal a novel intercellular signaling pathway mediated by adipose-derived exosomes and suggest that treatment targeting the secreted exosome-circCRIM1 may reverse TNBC progression.

Function and biomedical implications of exosomal microRNAs delivered by parenchymal and nonparenchymal cells in hepatocellular carcinoma

Small extracellular vesicles (exosomes) are important components of the tumor microenvironment. They are small membrane-bound vesicles derived from almost all cell types and play an important role in intercellular communication. Exosomes transmit biological molecules obtained from parent cells, such as proteins, lipids, and nucleic acids, and are involved in cancer development. MicroRNAs (miRNAs), the most abundant contents in exosomes, are selectively packaged into exosomes to carry out their biological functions. Recent studies have revealed that exosome-delivered miRNAs play crucial roles in the tumorigenesis, progression, and drug resistance of hepatocellular carcinoma (HCC). In addition, exosomes have great industrial prospects in the diagnosis, treatment, and prognosis of patients with HCC. This review summarized the composition and function of exosomal miRNAs of different cell origins in HCC and highlighted the association between exosomal miRNAs from stromal cells and immune cells in the tumor microenvironment and the progression of HCC. Finally, we described the potential applicability of exosomal miRNAs derived from mesenchymal stem cells in the treatment of HCC.

Extracellular vesicles: Emerging mediators of cell communication in gastrointestinal cancers exhibiting metabolic abnormalities

There is a complex interaction between pro-tumoural and anti-tumoural networks in the tumour microenvironment (TME). Throughout tumourigenesis, communication between malignant cells and various cells of the TME contributes to metabolic reprogramming. Tumour Dysregulation of metabolic pathways offer an evolutional advantage in the TME and enhance the tumour progression, invasiveness, and metastasis. Therefore, understanding these interactions within the TME is crucial for the development of innovative cancer treatments. Extracellular vesicles (EVs) serve as carriers of various materials that include microRNAs, proteins, and lipids that play a vital role in the communication between tumour cells and non-tumour cells. EVs are actively involved in the metabolic reprogramming process. This review summarized recent findings regarding the involvement of EVs in the metabolic reprogramming of various cells in the TME of gastrointestinal cancers. Additionally, we highlight identified microRNAs involved in the reprogramming process in this group of cancers and explained the abnormal tumour metabolism targeted by exosomal cargos as well as the novel potential therapeutic approaches.

EV-miRNA-Mediated Intercellular Communication in the Breast Tumor Microenvironment

Cancer research has prioritized the study of the tumor microenvironment (TME) as a crucial area of investigation. Understanding the communication between tumor cells and the various cell types within the TME has become a focal point. Bidirectional communication processes between these cells support cellular transformation, as well as the survival, invasion, and metastatic dissemination of tumor cells. Extracellular vesicles are lipid bilayer structures secreted by cells that emerge as important mediators of this cell-to-cell communication. EVs transfer their molecular cargo, including proteins and nucleic acids, and particularly microRNAs, which play critical roles in intercellular communication. Tumor-derived EVs, for example, can promote angiogenesis and enhance endothelial permeability by delivering specific miRNAs. Moreover, adipocytes, a significant component of the breast stroma, exhibit high EV secretory activity, which can then modulate metabolic processes, promoting the growth, proliferation, and migration of tumor cells. Comprehensive studies investigating the involvement of EVs and their miRNA cargo in the TME, as well as their underlying mechanisms driving tumoral capacities, are necessary for a deeper understanding of these complex interactions. Such knowledge holds promise for the development of novel diagnostic and therapeutic strategies in cancer treatment.

Unveiling the Yin-Yang Balance of M1 and M2 Macrophages in Hepatocellular Carcinoma: Role of Exosomes in Tumor Microenvironment and Immune Modulation

Hepatocellular carcinoma (HCC) is a primary liver cancer with a high mortality rate and limited treatment options. Recent research has brought attention to the significant importance of intercellular communication in the progression of HCC, wherein exosomes have been identified as critical agents facilitating cell-to-cell signaling. In this article, we investigate the impact of macrophages as both sources and targets of exosomes in HCC, shedding light on the intricate interplay between exosome-mediated communication and macrophage involvement in HCC pathogenesis. It investigates how exosomes derived from HCC cells and other cell types within the tumor microenvironment (TME) can influence macrophage behavior, polarization, and recruitment. Furthermore, the section explores the reciprocal interactions between macrophage-derived exosomes and HCC cells, stromal cells, and other immune cells, elucidating their role in tumor growth, angiogenesis, metastasis, and immune evasion. The findings presented here contribute to a better understanding of the role of macrophage-derived exosomes in HCC progression and offer new avenues for targeted interventions and improved patient outcomes.

Expression Analysis of hsa-miR-181a-5p, hsa-miR-143-3p, hsa-miR-132-3p and hsa-miR-23a-3p as Biomarkers in Colorectal Cancer-Relationship to the Body Mass Index

This work aims to investigate the expression levels of four preselected miRNAs previously linked to cancer and/or obesity, with the purpose of finding potential biomarkers in the clinical management of CRC developed by patients showing different BMI values. We analyzed samples from a total of 65 subjects: 43 affected by CRC and 22 without cancer. Serum and both subcutaneous and omental adipose tissues (SAT and OAT) were investigated, as well as tumor and non-tumor colorectal tissues in the case of the CRC patients. The relative expression (2^-∆∆Ct) levels of 4 miRNAs (hsa-miR-181a-5p, hsa-miR-143-3p, has-miR-132-3p and hsa-miR-23a-3p) were measured by RT-qPCR. Serum, SAT and OAT expression levels of these miRNAs showed significant differences between subjects with and without CRC, especially in the group of overweight/obese subjects. In CRC, serum levels of hsa-miR-143-3p clearly correlated with their levels in both SAT and OAT, independently of the BMI group. Moreover, hsa-miR-181a-5p could be considered as a biomarker in CRC patients with BMI ≥ 25 Kg/m² and emerges as a tumor location marker. We conclude that both adiposity and CRC induce changes in the expression of the miRNAs investigated, and hsa-miR-143-3p and hsa-miR-181a-5p expression analysis could be useful in the clinical management of CRC.

Adipocyte-derived extracellular vesicles: bridging the communications between obesity and tumor microenvironment

By the year 2035 more than 4 billion people might be affected by obesity and being overweight. Adipocyte-derived Extracellular Vesicles (ADEVs/ADEV-singular) are essential for communication between the tumor microenvironment (TME) and obesity, emerging as a prominent mechanism of tumor progression. Adipose tissue (AT) becomes hypertrophic and hyperplastic in an obese state resulting in insulin resistance in the body. This modifies the energy supply to tumor cells and simultaneously stimulates the production of pro-inflammatory adipokines. In addition, obese AT has a dysregulated cargo content of discharged ADEVs, leading to elevated amounts of pro-inflammatory proteins, fatty acids, and carcinogenic microRNAs. ADEVs are strongly associated with hallmarks of cancer (proliferation and resistance to cell death, angiogenesis, invasion, metastasis, immunological response) and may be useful as biomarkers and antitumor therapy strategy. Given the present developments in obesity and cancer-related research, we conclude by outlining significant challenges and significant advances that must be addressed expeditiously to promote ADEVs research and clinical applications.

Role of adipocyte-derived extracellular vesicles during the progression of liver inflammation to hepatocellular carcinoma

Extracellular vesicles are membrane-bound cargos that vary in size and are stably transported through various bodily fluids. Extracellular vesicles communicate information between the cells and organs. Extracellular vesicles from the diseased cells alter cellular responses of the recipient cells contributing to disease progression. In obesity, adipocytes become hypertrophic and the extracellular vesicles from these dysfunctional adipocytes showed altered cargo contents instigating pathophysiological response leading to chronic liver diseases. In this review, the role of adipocyte-derived extracellular vesicles on the progression of liver inflammation, fibrosis, cirrhosis, and hepatocellular carcinoma are extensively discussed. Newer approaches are crucial to take advantage of extracellular vesicles and their content as biomarkers to diagnose initial liver inflammation before reaching to an irreversible liver failure stage.

Role of Extracellular Vesicles in Liver Diseases

Extracellular vesicles (EVs) are cell-derived membrane structures that are formed by budding from the plasma membrane or originate from the endosomal system. These microparticles (100 nm-100 µm) or nanoparticles (>100 nm) can transport complex cargos to other cells and, thus, provide communication and intercellular regulation. Various cells, such as hepatocytes, liver sinusoidal endothelial cells (LSECs) or hepatic stellate cells (HSCs), secrete and take up EVs in the healthy liver, and the amount, size and content of these vesicles are markedly altered under pathophysiological conditions. A comprehensive knowledge of the modified EV-related processes is very important, as they are of great value as biomarkers or therapeutic targets. In this review, we summarize the latest knowledge on hepatic EVs and the role they play in the homeostatic processes in the healthy liver. In addition, we discuss the characteristic changes of EVs and their potential exacerbating or ameliorating effects in certain liver diseases, such as non-alcoholic fatty liver disease (NAFLD), alcoholic fatty liver disease (AFLD), drug induced liver injury (DILI), autoimmune hepatitis (AIH), hepatocarcinoma (HCC) and viral hepatitis.

Exosomal cargos-mediated metabolic reprogramming in tumor microenvironment

Metabolic reprogramming is one of the hallmarks of cancer. As nutrients are scarce in the tumor microenvironment (TME), tumor cells adopt multiple metabolic adaptations to meet their growth requirements. Metabolic reprogramming is not only present in tumor cells, but exosomal cargos mediates intercellular communication between tumor cells and non-tumor cells in the TME, inducing metabolic remodeling to create an outpost of microvascular enrichment and immune escape. Here, we highlight the composition and characteristics of TME, meanwhile summarize the components of exosomal cargos and their corresponding sorting mode. Functionally, these exosomal cargos-mediated metabolic reprogramming improves the "soil" for tumor growth and metastasis. Moreover, we discuss the abnormal tumor metabolism targeted by exosomal cargos and its potential antitumor therapy. In conclusion, this review updates the current role of exosomal cargos in TME metabolic reprogramming and enriches the future application scenarios of exosomes.

CircHOMER1 inhibits porcine adipogenesis via the miR-23b/SIRT1 axis

Fat deposition is critical to pork quality. However, the mechanism of fat deposition remains to be elucidated. Circular RNAs (circRNAs) are ideal biomarkers and are involved in adipogenesis. Here, we investigated the effect and mechanism of circHOMER1 on porcine adipogenesis in vitro and in vivo. Western blotting, Oil red O staining, and HE staining were used to assess the function of circHOMER1 in adipogenesis. The results showed that circHOMER1 inhibited adipogenic differentiation of porcine preadipocytes and suppressed adipogenesis in mice. Dual-luciferase reporter gene, RIP, and pull-down assays demonstrated that miR-23b directly bound to circHOMER1 and the 3'-UTR of SIRT1. Rescue experiments further illustrated the regulatory relationship among circHOMER1, miR-23b, and SIRT1. Conclusively, we demonstrate that circHOMER1 plays an inhibitory role in porcine adipogenesis through miR-23b and SIRT1. The present study revealed the mechanism of porcine adipogenesis, which may be helpful to improve pork quality.

Extracellular Vesicles in Cancer Drug Resistance: Implications on Melanoma Therapy

Extracellular vesicles (EVs) are involved in the pathogenesis of neoplastic diseases. Their role in mediating drug resistance has been widely described in several types of cancers, including melanoma. EVs can mediate drug resistance through several different mechanisms, such as drug-sequestration, transfer of pro-survival proteins and RNA, induction of cancer stem cell-like features and interaction with cells of the tumor microenvironment and immune-system. Melanoma is a highly immunogenic tumor originating from the malignant transformation of melanocytes. Several therapeutic strategies currently used in the treatment of melanoma and the combination of BRAF and MEK-inhibitors, as well as immune check-point inhibitors (ICI), have consistently improved the overall survival time of melanoma patients. However, the development of resistance is one of the biggest problems leading to a poor clinical outcome, and EVs can contribute to this. EVs isolated from melanoma cells can contain "sequestered" chemotherapeutic drugs in order to eliminate them, or bioactive molecules (such as miRNA or proteins) that have been proven to play a crucial role in the transmission of resistance to sensitive neoplastic cells. This leads to the hypothesis that EVs could be considered as resistance-mediators in sensitive melanoma cells. These findings are a pivotal starting point for further investigations to better understand EVs' role in drug resistance mechanisms and how to target them. The purpose of this review is to summarize knowledge about EVs in order to develop a deeper understanding of their underlying mechanisms. This could lead to the development of new therapeutic strategies able to bypass EV-mediated drug-resistance in melanoma, such as by the use of combination therapy, including EV release inhibitors.

Extracellular Vesicles as Carriers of Adipokines and Their Role in Obesity

Extracellular vesicles (EVs) have lately arisen as new metabolic players in energy homeostasis participating in intercellular communication at the local and distant levels. These nanosized lipid bilayer spheres, carrying bioactive molecular cargo, have somehow changed the paradigm of biomedical research not only as a non-classic cell secretion mechanism, but as a rich source of biomarkers and as useful drug-delivery vehicles. Although the research about the role of EVs on metabolism and its deregulation on obesity and associated pathologies lagged slightly behind other diseases, the knowledge about their function under normal and pathological homeostasis is rapidly increasing. In this review, we are focusing on the current research regarding adipose tissue shed extracellular vesicles including their characterization, size profile, and molecular cargo content comprising miRNAs and membrane and intra-vesicular proteins. Finally, we will focus on the functional aspects attributed to vesicles secreted not only by adipocytes, but also by other cells comprising adipose tissue, describing the evidence to date on the deleterious effects of extracellular vesicles released by obese adipose tissue both locally and at the distant level by interacting with other peripheral organs and even at the central level.

miR-23a/b clusters are not essential for the pathogenesis of osteoarthritis in mouse aging and post-traumatic models

Osteoarthritis (OA), the most prevalent aging-related joint disease, is characterized by insufficient extracellular matrix synthesis and articular cartilage degradation and is caused by various risk factors including aging and traumatic injury. Most microRNAs (miRNAs) have been associated with pathogenesis of osteoarthritis (OA) using in vitro models. However, the role of many miRNAs in skeletal development and OA pathogenesis is uncharacterized in vivo using genetically modified mice. Here, we focused on miR-23-27-24 clusters. There are two paralogous miR-23-27-24 clusters: miR-23a-27a-24-2 (miR-23a cluster) and miR-23b-27b-24-1 (miR-23b cluster). Each miR-23a/b, miR-24, and miR-27a/b is thought to function coordinately and complementary to each other, and the role of each miR-23a/b, miR-24, and miR-27a/b in OA pathogenesis is still controversial. MiR-23a/b clusters are highly expressed in chondrocytes and the present study examined their role in OA. We analyzed miRNA expression in chondrocytes and investigated cartilage-specific miR-23a/b clusters knockout (Col2a1-Cre; miR-23a/bflox/flox: Cart-miR-23clus KO) mice and global miR-23a/b clusters knockout (CAG-Cre; miR-23a/bflox/flox: Glob-miR-23clus KO) mice. Knees of Cart- and Glob-miR-23a/b clusters KO mice were evaluated by histological grading systems for knee joint tissues using aging model (12 and/or 18 month-old) and surgically-induced OA model. miR-23a/b clusters were among the most highly expressed miRNAs in chondrocytes. Skeletal development of Cart- and Glob-miR-23clus KO mice was grossly normal although Glob-miR-23clus KO had reduced body weight, adipose tissue and bone density. In the aging model and surgically-induced OA model, Cart- and Glob-miR-23clus KO mice exhibited mild OA-like changes such as proteoglycan loss and cartilage fibrillation. However, the histological scores were not significantly different in terms of the severity of OA in Cart- and Glob-miR-23clus KO mice compared with control mice. Together, miR-23a/b clusters, composed of miR-23a/b, miR-24, miR-27a/b do not significantly contribute to OA pathogenesis.

Exosomal microRNA-342-5p from human umbilical cord mesenchymal stem cells inhibits preeclampsia in rats

We aimed to investigate the inhibitory effect of human umbilical cord mesenchymal stem cell (hucMSC)-derived exosomes (hucMSC-Exos) transmitting microRNA-342-5p (miR-342-5p) on the development of preeclampsia (PE) by targeting programmed cell death 4 (PDCD4). The primary hucMSCs were cultured and transfected with miR-342-5p, and the exosomes (Exo) were extracted from the hucMSCs. PE rats were performed with an intraperitoneal injection of L-NAME from days 11 to 19 of gestation, and injection of Exo, Exo-negative control (NC), Exo-miR-342-5p agomir, Exo-miR-342-5p antagomir, and overexpressing PDCD4 (oe-PDCD4) vector into the placenta on the 16th day of pregnancy. HE staining was utilized to observe the pathological changes in placental tissues. TUNEL staining was implemented to evaluate cell apoptosis in placental tissues. Blood pressure and 24-h urinary protein in pregnant rats were measured by a non-invasive rat tail artery blood pressure measurement and protein auto-analyzer. Expressions of miR-342-5p, PDCD4, proinflammatory cytokines (TNF-α and IL-1β), and anti-inflammatory cytokines (IL-10 and TGF-β) were detected by RT-qPCR, and PDCD4 protein expression was determined by Western blot. The interaction between miR-342-5p and PDCD4 was analyzed by luciferase activity assay. MiR-342-5p was downregulated while PDCD4 was upregulated in the placental tissues of PE rats. HucMSC-Exo relieved pathology and suppressed inflammatory response, and apoptosis in the placental tissues, as well as reducing blood pressure and 24-h urinary protein of PE rats. Elevated miR-342-5p enhanced the promoting influence of hucMSC-Exo on PE rats, while inhibited miR-342-5p reversed the functions of hucMSC-Exo on PE rats. miR-342-5p targeted PDCD4. Overexpression of PDCD4 worsened the development of PE in rats. HucMSC-Exo conveying elevated miR-342-5p inhibits the development of PE in a rat model through downregulating PDCD4.

Extracellular Vesicles in Cancer Drug Resistance: Roles, Mechanisms, and Implications

Extracellular vesicles (EVs) are cell-derived nanosized vesicles that mediate cell-to-cell communication via transporting bioactive molecules and thus are critically involved in various physiological and pathological conditions. EVs contribute to different aspects of cancer progression, such as cancer growth, angiogenesis, metastasis, immune evasion, and drug resistance. EVs induce the resistance of cancer cells to chemotherapy, radiotherapy, targeted therapy, antiangiogenesis therapy, and immunotherapy by transferring specific cargos that affect drug efflux and regulate signaling pathways associated with epithelial-mesenchymal transition, autophagy, metabolism, and cancer stemness. In addition, EVs modulate the reciprocal interaction between cancer cells and noncancer cells in the tumor microenvironment (TME) to develop therapy resistance. EVs are detectable in many biofluids of cancer patients, and thus are regarded as novel biomarkers for monitoring therapy response and predicting prognosis. Moreover, EVs are suggested as promising targets and engineered as nanovehicles to deliver drugs for overcoming drug resistance in cancer therapy. In this review, the biological roles of EVs and their mechanisms of action in cancer drug resistance are summarized. The preclinical studies on using EVs in monitoring and overcoming cancer drug resistance are also discussed.

Obesity-Related Cross-Talk between Prostate Cancer and Peripheral Fat: Potential Role of Exosomes

Simple Summary

Obesity is involved in many aspects of prostate cancer progression as a risk factor for prostate cancer, especially in the process of biochemical recurrence in the prostate. Approximately 27–53% of prostate cancer patients can develop biochemical recurrence after radical prostatectomy, which poses difficulties in the clinical management of prostate cancer, and this is closely related to the release of exosomes from adipose tissue in the obese state. In this review, we summarize the crosstalk between prostate cancer peripheral adiposity and prostate cancer and discuss the potential role of exosomes in this process and the prospects for the use of adipose exosomes. Exosomes play an important role in the crosstalk between the two this may be a new basis to explain obesity as a biochemical recurrence after prostate cancer surgery and a potential avenue for future prostate therapy.

Abstract

The molecular mechanisms of obesity-induced cancer progression have been extensively explored because of the significant increase in obesity and obesity-related diseases worldwide. Studies have shown that obesity is associated with certain features of prostate cancer. In particular, bioactive factors released from periprostatic adipose tissues mediate the bidirectional communication between periprostatic adipose tissue and prostate cancer. Moreover, recent studies have shown that extracellular vesicles have a role in the relationship between tumor peripheral adipose tissue and cancer progression. Therefore, it is necessary to investigate the feedback mechanisms between prostate cancer and periglandular adipose and the role of exosomes as mediators of signal exchange to understand obesity as a risk factor for prostate cancer. This review summarizes the two-way communication between prostate cancer and periglandular adipose and discusses the potential role of exosomes as a cross-talk and the prospect of using adipose tissue as a means to obtain exosomes in vitro. Therefore, this review may provide new directions for the treatment of obesity to suppress prostate cancer.

Exosomes Derived from Hypoxic Glioma Cells Reduce the Sensitivity of Glioma Cells to Temozolomide Through Carrying miR-106a-5p

Background

Hypoxia is a frequent feature of solid tumors which significantly affects the efficacy of treatments such as chemotherapy. In addition, exosomes from hypoxic cancer cells could contribute to the chemoresistance of tumor cells through carrying miRNAs. It has been shown that miR-106-5p level was upregulated in glioma. However, whether exosomes derived from hypoxic glioma cells could affect temozolomide (TMZ) resistance in glioma through carrying miR-106a-5p remains unexplored.

Methods

Exosomes were isolated from glioma cells under normoxia or hypoxia condition. EdU staining and flow cytometry assays were used to assess the cell proliferation and cell apoptosis. The relation between miR-106a-5p and PTEN was investigated by dual luciferase assay.

Results

MiR-106a-5p was enriched in exosomes derived from hypoxic glioma cells compared to exosomes from cells under normoxia condition. Additionally, hypoxic glioma cells were able to transfer exosomes to glioma cells, resulting in a significant increase of miR-106a-5p level in cells. TMZ remarkably suppressed glioma cell proliferation and triggered cell apoptosis. However, hypoxic glioma cell-derived exosomes markedly promoted the proliferation and suppressed the apoptosis in TMZ-treated glioma cells, and miR-106a-5p inhibitor was able to abolish these phenomena. Meanwhile, PTEN was verified to be a direct target of miR-106a-5p. Furthermore, TMZ elevated PTEN and Bax level and reduced p-Akt level in glioma cells, whereas these changes were reversed by hypoxia glioma cell-derived exosomes. Furthermore, hypoxia glioma cell-derived exosomes reduced the sensitivity of glioma cells to TMZ in vivo via downregulating PTEN.

Conclusion

Collectively, exosomal miR-106a-5p derived from hypoxia glioma cells could reduce the sensitivity of glioma cells to TMZ through downregulating PTEN. Thus, our study might provide new strategies for improving the clinical efficacy of TMZ on glioma.

Adipose tissue-to-breast cancer crosstalk: Comprehensive insights

The review focuses on mechanistic evidence for the link between obesity and breast cancer. According to the IARC study, there is sufficient evidence that obesity is closely related to a variety of cancers. Among them, breast cancer is particularly disturbed by adipose tissue due to the unique histological structure of the breast. The review introduces the relationship between obesity and breast cancer from two aspects, including factors that promote tumorigenesis or metastasis. We summarize alterations in adipokines and metabolic pathways that contribute to breast cancer development. Breast cancer metastasis is closely related to obesity-induced pro-inflammatory microenvironment, adipose stem cells, and miRNAs. Based on the mechanism by which obesity causes breast cancer, we list possible therapeutic directions, including reducing the risk of breast cancer and inhibiting the progression of breast cancer. We also discussed the risk of autologous breast remodeling and fat transplantation. Finally, the causes of the obesity paradox and the function of enhancing immunity are discussed. Evaluating the balance between obesity-induced inflammation and enhanced immunity warrants further study.

Role of Exosomes in Immunotherapy of Hepatocellular Carcinoma

Simple Summary

Hepatocellular carcinoma is one of the most lethal malignancies, having a significantly poor prognosis. Immunotherapy, as an emerging tumor treatment option, provides new hope for many cancer patients. However, a large proportion of patients do not benefit from immunotherapy. As a critical cell-to-cell communication mediator in the tumor immune microenvironment, exosomes may play a unique role in hepatocellular carcinoma immune response and thus affect the efficiency of immunotherapy. In this review, we discuss related research on the roles of exosomes in the current immunotherapy resistance mechanism of hepatocellular carcinoma. Furthermore, we also clarify the excellent predictive value of exosomes and the roles they play in improving immunotherapy efficacy for hepatocellular carcinoma patients. We hope that our review can help readers to gain a more comprehensive understanding of exosomes’ roles in hepatocellular carcinoma immunotherapy.

Abstract

Hepatocellular carcinoma (HCC) is one of the most lethal malignancies, having a significantly poor prognosis and no sufficiently efficient treatments. Immunotherapy, especially immune checkpoint inhibitors (ICIs), has provided new therapeutic approaches for HCC patients. Nevertheless, most patients with HCC do not benefit from immunotherapy. Exosomes are biologically active lipid bilayer nano-sized vesicles ranging in size from 30 to 150 nm and can be secreted by almost any cell. In the HCC tumor microenvironment (TME), numerous cells are involved in tumor progression, and exosomes—derived from tumor cells and immune cells—exhibit unique composition profiles and act as intercellular communicators by transporting various substances. Showing the dual characteristics of tumor promotion and suppression, exosomes exert multiple functions in shaping tumor immune responses in the crosstalk between tumor cells and surrounding immune cells, mediating immunotherapy resistance by affecting the PD-1/PD-L1 axis or the anti-tumor function of immune cells in the TME. Targeting exosomes or the application of exosomes as therapies is involved in many aspects of HCC immunotherapies (e.g., ICIs, tumor vaccines, and adoptive cell therapy) and may substantially enhance their efficacy. In this review, we discuss the impact of exosomes on the HCC TME and comprehensively summarize the role of exosomes in immunotherapy resistance and therapeutic application. We also discuss the potential of exosomes as biomarkers for predicting the efficacy of immunotherapy to help clinicians in identifying HCC patients who are amenable to immunotherapies.

Roles of small extracellular vesicles in the development, diagnosis and possible treatment strategies for hepatocellular carcinoma (Review)

Hepatocellular carcinoma (HCC) is the most common malignancy of hepatocytes accounting for 75-85% of primary hepatic carcinoma cases. Small extracellular vesicles (sEVs), previously known as exosomes with a diameter of 30-200 nm, can transport a variety of biological molecules between cells, and have been proposed to function in physiological and pathological processes. Recent studies have indicated that the cargos of sEVs are implicated in intercellular crosstalk among HCC cells, paratumor cells and the tumor microenvironment. sEV-encapsulated substances (including DNA, RNA, proteins and lipids) regulate signal transduction pathways in recipient cells and contribute to cancer initiation and progression in HCC. In addition, the differential expression of sEV cargos between patients facilitates the potential utility of sEVs in the diagnosis and prognosis of patients with HCC. Furthermore, the intrinsic properties of low immunogenicity and high stability render sEVs ideal vehicles for targeted drug delivery in the treatment of HCC. The present review article summarizes the carcinogenic and anti-neoplastic capacities of sEVs and discusses the potential and prospective diagnostic and therapeutic applications of sEVs in HCC.

MiR-23b Promotes Porcine Preadipocyte Differentiation via SESN3 and ACSL4

Genetic improvement of pork quality is one of the hot topics in pig germplasm innovation. Backfat thickness and intramuscular fat content are important indexes of meat quality. MiRNAs are becoming recognized as a crucial regulator of adipose development. Therefore, it is crucial to understand how miR-23b regulates fat metabolism at the molecular level. In the present study, Oil Red O staining, and Western blot were used to evaluate the effect of miR-23b on the differentiation of porcine preadipocytes. Dual-luciferase reporter gene assay, pulldown, and RIP were used to reveal the mechanism of miR-23b regulating cell differentiation. The findings demonstrated that miR-23b promotes the expression of adipogenic factors and increases the content of lipid droplets, thus promoting the differentiation of preadipocytes. Further research found that miR-23b can directly bind to the 3’UTR of SESN3 to regulate adipogenic differentiation. In addition, it was speculated that miR-23b controls cell differentiation by positively regulating the expression of ACSL4 in other ways. Here, we demonstrate that miR-23b promotes the differentiation of porcine preadipocytes by targeting SESN3 and promoting the expression of ACSL4. The present study is meaningful to the improvement of pork quality and the development of animal husbandry.

Small extracellular vesicles and liver diseases: From diagnosis to therapy

Extracellular vesicles (EVs), especially small EVs (sEVs) derived from liver cells, have been the focus of much attention in the normal physiology and pathogenesis of various diseases affecting the liver. sEVs are approximately 100 nm in size, enclosed within lipid bilayers, and are very stable. The lipids, proteins, and nucleic acids, including miRNAs, contained within these vesicles are known to play important roles in intercellular communication. This mini-review summarizes the application of sEVs. First, liver diseases and the related diagnostic markers are described, and the current active status of miRNA research in diagnosis of hepatocellular carcinoma (HCC) is reported. Second, the biodistribution and pharmacokinetics of sEVs are described, and the liver is highlighted as the organ with the highest accumulation of sEVs. Third, the relationship between sEVs and the pathogenesis of liver disorders is described with emphesis on the current active status of miRNA research in HCC recurrence and survival. Finally, the possibility of future therapy using sEVs from mesenchymal stem (stromal) cells for cirrhosis and other diseases is described.

Extracellular Vesicles and Hepatocellular Carcinoma: Opportunities and Challenges

The incidence of hepatocellular carcinoma (HCC) is increasing worldwide. Extracellular vesicles (EVs) contain sufficient bioactive substances and are carriers of intercellular information exchange, as well as delivery vehicles for nucleic acids, proteins and drugs. Although EVs show great potential for the treatment of HCC and their role in HCC progression has been extensively studied, there are still many challenges such as time-consuming extraction, difficult storage, easy contamination, and low drug loading rate. We focus on the biogenesis, morphological characteristics, isolation and extraction of EVs and their significance in the progression of HCC, tumor invasion, immune escape and cancer therapy for a review. EVs may be effective biomarkers for molecular diagnosis of HCC and new targets for tumor-targeted therapy.

The role of human umbilical cord mesenchymal stem cells-derived exosomal microRNA-431-5p in survival and prognosis of colorectal cancer patients

We aim to discuss the role of miR-431-5p in colorectal cancer (CRC) progression via regulating peroxiredoxin 1 (PRDX1). miR-431-5p and PRDX1 expression were detected in CRC tissues and cells, and the relationship between miR-431-5p expression and prognosis of CRC patients was analyzed. Exosomes were extracted from human umbilical cord mesenchymal stem cells (hUCMSCs) and co-cultured with LoVo cells. MTT assay, flow cytometry and Transwell assay were implemented to test cell viability, apoptosis and invasion and migration ability, respectively. The tumor growth was determined as well, and the binding relation between miR-431-5p and PRDX1 was confirmed. miR-431-5p was downregulated and PRDX1 was upregulated in CRC, and miR-431-5p downregulation was associated with poor prognosis. hUCMSC-Exos suppressed the malignant behaviors of LoVo cells, and overexpression of miR-431-5p further aggravated the inhibitory effect of hUCMSC-Exos on LoVo cells. hUCMSC-Exos inhibited PRDX1 expression via miR-431-5p. PRDX1 was targeted by miR-431-5p. miR-431-5p serves as a prognostic biomarker in CRC, and hUCMSC-Exos transfer of miR-431-5p decelerates CRC cell growth by inhibiting PRDX1.

Exosomes and ferroptosis: roles in tumour regulation and new cancer therapies

Research on the biological role of exosomes is rapidly developing, and recent evidence suggests that exosomal effects involve ferroptosis. Exosomes derived from different tissues inhibit ferroptosis, which increases tumour cell chemoresistance. Therefore, exosome-mediated regulation of ferroptosis may be leveraged to design anticancer drugs. This review discusses three pathways of exosome-mediated inhibition of ferroptosis: (1) the Fenton reaction; (2) the ferroptosis defence system, including the Xc-GSH-GPX4 axis and the FSP1/CoQ₁₀/NAD(P)H axis; and (3) lipid peroxidation. We also summarize three recent approaches for combining exosomes and ferroptosis in oncology therapy: (1) promoting exosome-inhibited ferroptosis to enhance chemotherapy; (2) encapsulating exosomes with ferroptosis inducers to inhibit cancers; and (3) developing therapies that combine exosomal inhibitors and ferroptosis inducers. This review will contribute toward establishing effective cancer therapies.

The Role of Extracellular Vesicles in Metabolic Reprogramming of the Tumor Microenvironment

The tumor microenvironment (TME) includes a network of cancerous and non-cancerous cells, together with associated blood vessels, the extracellular matrix, and signaling molecules. The TME contributes to cancer progression during various phases of tumorigenesis, and interactions that take place within the TME have become targets of focus in cancer therapy development. Extracellular vesicles (EVs) are known to be conveyors of genetic material, proteins, and lipids within the TME. One of the hallmarks of cancer is its ability to reprogram metabolism to sustain cell growth and proliferation in a stringent environment. In this review, we provide an overview of TME EV involvement in the metabolic reprogramming of cancer and stromal cells, which favors cancer progression by enhancing angiogenesis, proliferation, metastasis, treatment resistance, and immunoevasion. Targeting the communication mechanisms and systems utilized by TME-EVs is opening a new frontier in cancer therapy.

Extracellular Vesicle-Mediated Mitochondrial Reprogramming in Cancer

Simple Summary

Mitochondria are important organelles involved in several key cellular processes including energy production and cell death regulation. For this reason, it is unsurprising that mitochondrial function and structure are altered in several pathological states including cancer. Cancer cells present variate strategies to generate sufficient energy to sustain their high proliferation rates. These adaptative strategies can be mediated by extracellular signals such as extracellular vesicles. These vesicles can alter recipient cellular behavior by delivering their molecular cargo. This review explores the different EV-mediated mitochondrial reprogramming mechanisms supporting cancer survival and progression.

Abstract

Altered metabolism is a defining hallmark of cancer. Metabolic adaptations are often linked to a reprogramming of the mitochondria due to the importance of these organelles in energy production and biosynthesis. Cancer cells present heterogeneous metabolic phenotypes that can be modulated by signals originating from the tumor microenvironment. Extracellular vesicles (EVs) are recognized as key players in intercellular communications and mediate many of the hallmarks of cancer via the delivery of their diverse biological cargo molecules. Firstly, this review introduces the most characteristic changes that the EV-biogenesis machinery and mitochondria undergo in the context of cancer. Then, it focuses on the EV-driven processes which alter mitochondrial structure, composition, and function to provide a survival advantage to cancer cells in the context of the hallmarks of cancers, such as altered metabolic strategies, migration and invasiveness, immune surveillance escape, and evasion of apoptosis. Finally, it explores the as yet untapped potential of targeting mitochondria using EVs as delivery vectors as a promising cancer therapeutic strategy.

Biomarkers and Genetic Markers of Hepatocellular Carcinoma and Cholangiocarcinoma-What Do We Already Know

Simple Summary

Hepatocellular carcinoma and cholangiocarcinoma continue to remain a serious threat. In this review, we describe the most common biomarkers and genetic markers currently used in the diagnosis of hepatocellular carcinoma and cholangiocarcinoma. It can be observed that biomarkers and genetic markers might be applied in various parts of diagnosis including screening tests in a high-risk group, non-invasive detection, control of therapy, treatment selection, and control of recurrence. Also, it can be seen that nowadays there is a need for more specific markers that would improve the detection in early or very early stages of both types of cancers and further research should be focused on it.

Abstract

Hepatocellular carcinoma (HCC) is the most common primary liver cancer with an increasing worldwide mortality rate. Cholangiocarcinoma (CCA) is the second most common primary liver cancer. In both types of cancers, early detection is very important. Biomarkers are a relevant part of diagnosis, enabling non-invasive detection and control of cancer recurrence, as well as in the application of screening tests in high-risk groups. Furthermore, some of these biomarkers are useful in controlling therapy and treatment selection. Detection of some markers presents higher sensitivity and specificity in combination with other markers when compared with a single detection. Some gene aberrations are also prognostic markers in the two types of cancers. In the following review, we discuss the most common biomarkers and genetic markers currently being used in the diagnosis of hepatocellular carcinoma and cholangiocarcinoma.

Exosomes in Pathogenesis, Diagnosis, and Treatment of Hepatocellular Carcinoma

Exosomes are extracellular vesicles with a diameter of 30-150 nm that are released by most types of cells and have been confirmed to be involved in many physical and pathological processes, especially in cell to cell communication. Compared with other vesicles, exosomes have a unique double-layer saclike structure that allows them to be present stably in various body fluids, including blood, cerebrospinal fluid, urine, saliva, and serous cavity effusion. The cargoes of exosomes reflect the characteristics of host cells. Due to the nature of hepatocellular carcinoma (HCC) cells, heterogeneity in the bioactive substances usually exist in exosomes. In addition, exosomes can efficiently deliver cargoes to the target cells to exert pathological functions, playing important role in tumor occurrence, development, metastasis, immune regulation, and drug resistance. Previous studies have been shown that exosomes have wide applications in diagnosis and treatment of HCC. In this review, we discuss these recent findings and highlight the significant roles of exosomes in HCC, focusing on the effect and underlying mechanisms of exosomes to regulate HCC progression and the potential clinical value of exosomes as biomarkers and therapeutic targets.

Intercellular and interorgan crosstalk through adipocyte extracellular vesicles

Functional adipose tissue is essential for homeostatic maintenance of systemic metabolism. As such, adipose tissue dysfunction, like that seen in the obese state, directly contributes to system-wide pathological metabolism, leading to the development of type 2 diabetes and other obesity-associated comorbidities. In addition to the storage function of adipocytes, they also secrete numerous factors that robustly regulate metabolism-related pathways throughout the body. Many of these factors, in addition to other signaling proteins, RNA species and lipids, are found in extracellular vesicles (EVs) released from adipocytes. EVs are vesicles with a lipid bilayer, known to carry signaling proteins and lipids, mRNAs and miRNAs. Because of this diverse cargo, EVs can have robust and pleotropic signaling effects depending on the receiving target cells. We are only now starting to understand how adipocyte EVs can modulate metabolism within adipose tissue and beyond. Here, we highlight the current literature that demonstrates EV-mediated crosstalk between adipocytes and other tissues or distal cells. We become increasingly aware of the importance of these adipocyte-derived EV signals that establish a so far underappreciated endocrine system. Adipocyte EVs offer a new avenue for pharmacological manipulation of metabolism to treat obesity-related disease.

Role of Exosomes in Immune Microenvironment of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the most common primary liver cancer. Since most patients with HCC are diagnosed at the intermediate or advanced stage and because HCC has a high incidence of metastasis and recurrence, it is one of the leading causes of cancer death. Exosomes are a subtype of extracellular vesicles and are typically 30–150 nm in diameter. Originating from endosomes, they can be secreted by almost all living cells. They are widely present in various body fluids and serve as an important medium for the interactions between cells. A series of studies have revealed that exosomes-mediated intercellular transfer of proteins, nucleic acids, and metabolites plays a crucial role in the initiation and progression of HCC, hypoxia and angiogenesis, chemotherapy sensitivity, and cell death mode and regulates the immune microenvironment. In this paper, we reviewed the recent researches on the multiple roles of tumor-associated exosomes in the progression of HCC. We laid particular focus on those researches that reveal how exosomes regulate the tumor immune microenvironment (TIME) and how exosomal cargos affect the progression of HCC. Besides, we emphasize some prospective directions to achieve a more accurate and complete analysis of the HCC immune microenvironment.

Exosomes as potential diagnosis and treatment for liver cancer

BACKGROUND

Liver cancer is the fourth most significant cause of cancer-related death. Lack of early diagnosis strategy and a scarcity of efficient therapy constitute the main reasons for its lethality. Exosomes, which contain various bioactive molecules, are characterized by high biocompatibility, low immunogenicity, and high transport efficiency. As a result, exosomes have become a research hotspot and present significant potential for cancer diagnosis biomarkers, biotherapeutics, therapy targets, drug carriers and therapeutic agents.

AIM

To explore the potential of exosomes in the diagnosis and treatment of liver cancer.

METHODS

We conducted a systematic literature search via PubMed and Web of Science. The following keywords were used: "exosomal biomarkers", "exosomal therapy", "exosomal therapy", and "liver cancer" or "HCC". The duplicate data were deleted by EndNote software. Literature search focused on full-texts and references of each article were carefully checked. One author (Xiao-Cui Wei) screened the literature that met the following inclusion criteria: (1) Detection of exosomes or their contents in clinical samples (body fluid or tissue); or (2) Exosomes served as drug carriers or therapeutic factors. Two authors (Xiao-Cui Wei and Li-Juan Liu) independently reviewed all retained literature and analyzed the information.

RESULTS

A total of 1295 studies were identified using the systematic literature search. Of these, 835 duplicate studies were removed. A further 402 irrelevant studies were excluded due to being irrelevant, including other diseases, review articles, the literature containing neither clinical samples nor animal experiments, exosome-independent studies, methods for detecting exosomes, or articles in Chinese. Finally, 58 published papers were retained and analyzed in the study. It showed a list of potential exosomal biomarkers that were upregulated in the blood samples of patients with liver cancer. Those downregulated in exosomes might serve as possible biotherapeutics. Some exosomes derived from cells in vitro were used for cytology or animal experiments to explore the mechanism of these exosome contents in disease. These contents might serve as potential targets for liver cancer. Additionally, we also discussed that exosomes serve as drug carriers or therapeutic factors.

CONCLUSION

Exosomes might serve as potential biomarkers or therapeutic biotargets in liver cancer and have the potential to act as drug carriers and self-treatment factors for liver cancer patients.

The emerging roles and mechanisms of exosomal non-coding RNAs in the mutual regulation between adipose tissue and other related tissues in obesity and metabolic diseases

Exosomes (EXs) are the major types of extracellular vesicles (EVs) of 30-100 nm diameter that can be secreted by most cells to the extracellular environment. EXs transport endogenous cargoes (proteins, lipids, RNAs, etc.) to target cells and thereby triggers the release of these bioactive components, which then play important roles in regulating numerous biological processes under both physiological and pathological conditions. Throughout the studies in recent years, growing evidences have shown that EXs-derived non-coding RNAs (EXs-ncRNAs) are emerging as key players in cell-to-cell communication between adipose tissue and other related tissues in obesity and metabolic diseases. In this review, we will summarize the recent findings about EXs-ncRNAs, especially focus on the following aspects: 1) the biogenesis of EXs and emerging roles of EXs-ncRNAs, 2) the role of EXs-ncRNAs (EXs-miRNAs, EXs-lncRNAs, EXs-circRNAs, etc.) that were secreted by adipose-related tissues in promoting the differentiation of preadipocytes into mature and fully functional adipocytes, and 3) the crosstalk between the adipose tissue derived EXs-ncRNAs and the development of insulin resistance, obesity and various cancers. This review aims to reveal the emerging roles and mechanisms of EXs-ncRNAs in the mutual regulation of adipose tissue and its related tissues in obesity and metabolic diseases, so as to provide references for elucidating the etiology of obesity and related metabolic diseases and screening novel therapeutic targets.

Composition, isolation, identification and function of adipose tissue-derived exosomes

Exosomes are nano-sized extracellular vesicles (30–160 nm diameter) with lipid bilayer membrane secrete by various cells that mediate the communication between cells and tissue, which contain a variety of non-coding RNAs, mRNAs, proteins, lipids and other functional substances. Adipose tissue is important energy storage and endocrine organ in the organism. Recent studies have revealed that adipose tissue-derived exosomes (AT-Exosomes) play a critical role in many physiologically and pathologically functions. Physiologically, AT-Exosomes could regulate the metabolic homoeostasis of various organs or cells including liver and skeletal muscle. Pathologically, they could be used in the treatment of disease and or that they may be involved in the progression of the disease. In this review, we describe the basic principles and methods of exosomes isolation and identification, as well as further summary the specific methods. Moreover, we categorize the relevant studies of AT-Exosomes and summarize the different components and biological functions of mammalian exosomes. Most importantly, we elaborate AT-Exosomes crosstalk within adipose tissue and their functions on other tissues or organs from the physiological and pathological perspective. Based on the above analysis, we discuss what remains to be discovered problems in AT-Exosomes studies and prospect their directions needed to be further explored in the future.

The impact of obesity on adipocyte-derived extracellular vesicles

Recently, the emerging roles of adipocyte-derived extracellular vesicles (EVs) linking obesity and its comorbidities have been recognized. In obese subjects, adipocytes are having hypertrophic growth and are under stressed. The dysfunction adipocytes dysregulate the assembly of the biological components in the EVs including exosomes. This article critically reviews the current findings on the impact of obesity on the exosomal cargo contents that induce the pathophysiological changes. Besides, this review also summarizes the understanding on how obesity affects the biogenesis of adipocyte-derived exosomes and the exosome secretion. Furthermore, the differences of the exosomal contents in different adipose depots, and the impact of obesity on the exosomes that are derived from the stromal vascular fraction such as the adipose tissue macrophages and adipocyte-derived stem cells will also be discussed. The current development and potential application of exosome-based therapy will be summarized. This review provides crucial information for the design of novel exosome-based therapy for the treatment of obesity and its comorbidities.

The Role of miR-23b in Cancer and Autoimmune Disease

Short-stranded miRNAs are single-stranded RNA molecules involved in the regulation of gene expression. miRNAs are involved in a variety of cellular physiological processes, including cell proliferation, differentiation, and apoptosis. miR-23b have been identified to act both as oncogenes and as tumor suppressors. In addition, miR-23b is related to inflammation resistance to various autoimmune diseases and restrained inflammatory cell migration. The characterization of the specific alterations in the patterns of miR-23b expression in cancer and autoimmune disease has great potential for identifying biomarkers for early disease diagnosis, as well as for potential therapeutic intervention in various diseases. In this review, we summarize the ever-expanding role of miR-23b and its target genes in different models and offer insight into how this multifunctional miRNA modulates tumor cell proliferation and apoptosis or inflammatory cell activation, differentiation, and migration.

RETRACTED: microRNA-6785-5p-loaded human umbilical cord mesenchymal stem cells-derived exosomes suppress angiogenesis and metastasis in gastric cancer via INHBA

This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of the Editor-in-Chief. Concern was raised about the reliability of the Western blot results in Figs. 1D+F, 2G, 3C, 4C and 6C, which appear to have the same eyebrow shaped phenotype as many other publications tabulated here (https://docs.google.com/spreadsheets/d/149EjFXVxpwkBXYJOnOHb6RhAqT4a2llhj9LM60MBffM/edit#gid=0). The journal requested the corresponding author comment on these concerns and provide the raw data. However the authors were not able to satisfactorily fulfil this request and therefore the Editor-in-Chief decided to retract the article.

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

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

Exosomal non-coding RNAs in Hepatobiliary Cancer: A Rising Star

Hepatobiliary cancers are a heterogeneous group of malignancies with a dismal prognosis. Despite intensive research efforts focused on these tumors, methods for early diagnosis and effective targeted therapies are still lacking. Exosomes, released by most cells, exist in all kinds of body fluids and play an important role in cell-to-cell communication. They are small membranous vesicles containing biological molecules, such as noncoding RNAs (ncRNAs), which are not translated into proteins, but they exert effects on the regulation of gene transcription and translation. There is growing evidence for the essential roles of ncRNAs in exosomes in both physiological and pathological conditions of hepatobiliary cancers. They have been identified as sensitive diagnostic biomarkers as well as potential therapeutic targets. The present review discusses recent findings in the crosstalk between hepatobiliary cancers cells and the surrounding cells of the microenvironment and discuss their potential clinical usage.

Role of extracellular vesicles in liver diseases and their therapeutic potential

More than eight hundred million people worldwide have chronic liver disease, with two million deaths per year. Recurring liver injury results in fibrogenesis, progressing towards cirrhosis, for which there doesn't exists any cure except liver transplantation. Better understanding of the mechanisms leading to cirrhosis and its complications is needed to develop effective therapies. Extracellular vesicles (EVs) are released by cells and are important for cell-to-cell communication. EVs have been reported to be involved in homeostasis maintenance, as well as in liver diseases. In this review, we present current knowledge on the role of EVs in non-alcoholic fatty liver disease and non-alcoholic steatohepatitis, alcohol-associated liver disease, chronic viral hepatitis, primary liver cancers, acute liver injury and liver regeneration. Moreover, therapeutic strategies involving EVs as targets or as tools to treat liver diseases are summarized.