Exosomal transfer of vasorin expressed in hepatocellular carcinoma cells promotes migration of human umbilical vein endothelial cells

Tumorigenesis, diagnosis, and therapeutic potential of exosomes in liver cancer

Hepatocellular carcinoma (HCC, also called primary liver cancer) is one of the most fatal cancers in the world. Due to the insidiousness of the onset of HCC and the lack of effective treatment methods, the prognosis of HCC is extremely poor, and the 5-year average survival rate is less than 10%. Exosomes are nano-sized microvesicle and contain various components such as nucleic acids, proteins, and lipids. Exosomes are important carriers for signal transmission or transportation of material from cell to cell or between cells and tissues. In recent years, exosomes have been considered as potential therapeutic targets of HCC. A large number of reports indicate that exosomes play a key role in the establishment of an HCC microenvironment, as well as the development, progression, invasion, metastasis, and even the diagnosis, treatment, and prognosis of HCC. However, the exact molecular mechanisms and roles of exosomes in these processes remain unclear. We believe that elucidation of the regulatory mechanism of HCC-related exosomes and its signaling pathway and analysis of its clinical applications in the diagnosis and treatment of HCC can provide useful clues for future treatment regimens for HCC. This article discusses and summarizes the research progress of HCC-related exosomes and their potential clinical applications.

Vasorin stimulates malignant progression and angiogenesis in glioma

Glioma, the most common human primary brain tumor, is characterized by invasive capabilities and angiogenesis. Vasorin (VASN), a transmembrane protein, is reported to be associated with vascular injury repair and is overexpressed in some human tumors. However, its role in tumor progression and angiogenesis in glioma is unknown. In this study, VASN was shown to be overexpressed in high‐grade gliomas, and the expression level correlated with tumor grade and microvessel density in glioma specimens. Glioma patients with high VASN expression had a shorter overall survival time. Knockdown of VASN in glioma cells by shRNA significantly inhibited the malignancy of glioma, including cell proliferation, colony formation, invasion, and sphere formation. Ectopic expression of VASN increased glioma progression in vitro. The expression of VASN correlated with the mesenchymal type of glioblastoma multiforme (GBM) subtyped by gene set enrichment analysis (GSEA). Our results showed that the concentration of VASN was increased in the conditioned medium (CM) from glioma cells with VASN overexpression, and the CM from glioma cells with knockdown or overexpressed VASN inhibited or promoted HUVEC migration and tubulogenesis in vitro, respectively. Glioma growth and angiogenesis were stimulated upon ectopic expression of VASN in vivo. The STAT3 and NOTCH pathways were found to be activated and inhibited by VASN overexpression. Our findings suggest that VASN stimulates tumor progression and angiogenesis in glioma, and, as such, represents a novel therapeutic target for glioma.

VASN promotes YAP/TAZ and EMT pathway in thyroid carcinogenesis in vitro

BACKGROUND

Thyroid cancer incidence has been continuity growing globally. To Find reliable molecular biomarkers to assess prognosis and select optimal treatment is necessary. VASN is a protein-coding gene that plays a vital part in tumor development and angiogenesis. Analyzing the TCGA dates, we found VASN could be a potential marker in assessing thyroid prognosis. The act of VASN in thyroid cancer is not explicit. In this article, we investigate the function of VASN expression in thyroid cancer.

METHODS

The Cancer Genome Atlas (TCGA) unpaired thyroid cancer and normal RNA-seq data was download and our paired thyroid cancer, and a polymerase chain reaction analyzed normal samples. The expression of VASN was regulated by transfected small interfering RNA, and the function of VASN was determined through migration, invasion and cell proliferation assays. Western blot assay was performed to reveal the relation between the VASN expression and YAP/TAZ pathway, epithelial-mesenchymal transition in thyroid carcinogenesis.

RESULTS

The significant upregulation of VASN in papillary thyroid carcinoma tissues associated to normal thyroid tissues was revealed by our data and TCGA data. VASN overexpression was significantly correlated to lymph node metastasis, tumor stage and tumor size. In the cell, experiments showed that VASN low expression significantly suppressed the migration, invasion, and proliferation. Western blot assay proves the effect of VASN expression on YAP/TAZ pathway and epithelial-mesenchymal transition.

CONCLUSION

VASN plays a crucial oncogene in thyroid cancer. Our results indicate that VASN could be a biomarker of thyroid cancer and may act in the YAP/TAZ pathway to regulate epithelial-mesenchymal transition (EMT).

Exosome-mediated communication in the tumor microenvironment contributes to hepatocellular carcinoma development and progression

The tumor microenvironment (TME) is an essential intrinsic portion of hepatocellular carcinoma (HCC) for the regulation of its origination, development, invasion, and metastasis. As emerging components of the tumor-host interaction, exosomes are increasingly recognized as professional carriers of information in TME and as pivotal molecular entities involved in tumorigenic microenvironment setup. However, much remains unknown about the role of the exosome communication system within TME in the development and progression of HCC. In this review, we focus on the roles and probable mechanisms of TME in HCC and show the exosome-based immune regulation in TME to promote HCC. Multiple processes are involved in HCC, including tumor survival, growth, angiogenesis, invasion, and metastasis. We also discuss the specific roles of exosomes in HCC processes by molding hospitable TME for HCC, such as providing energy, transmitting protumor signals, and evading inhibitory signals. In addition, exosomes induce angiogenesis by changing the biological characteristics of endothelial cells and directly regulating proangiogenic and propermeability factors. Furthermore, exosomes may lead to HCC metastatic invasion by epithelial-mesenchymal transformation, extracellular matrix degradation, and vascular leakage. Finally, we summarize the therapeutic usage of exosomes in the HCC microenvironment and attempt to provide a theoretical reference for modern antitumor agents designed to target these mechanisms.

Exosome plays an important role in the development of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most malignant cancers around the world. However, the early biomarkers for its detection and treatment are limited currently. Exosomes, classified as intercellular messenger shuttling their cargoes between cells, regulate cell differentiation and tissue development. They contain messenger RNA (mRNA), microRNA (miRNA), long non-coding RNA (lncRNA), circular RNA (circRNA), proteins, lipids and transcription factors. Therefore, exosomes play a crucial role in the development of HCC. In this review, we highlight the exosomal cargoes which could serve as biomarkers for the prediction and diagnosis of HCC. Exosomes are involved in metastases of HCC and they show great potential in immunotherapy and drug resistance mechanism. In summary, exosome suggests new clues in clinical application of HCC.

Review of the Isolation, Characterization, Biological Function, and Multifarious Therapeutic Approaches of Exosomes

Exosomes are extracellular vesicles that contain a specific composition of proteins, lipids, RNA, and DNA. They are derived from endocytic membranes and can transfer signals to recipient cells, thus mediating a novel mechanism of cell-to-cell communication. They are also thought to be involved in cellular waste disposal. Exosomes play significant roles in various biological functions, including the transfer of biomolecules such as RNA, proteins, enzymes, and lipids and the regulation of numerous physiological and pathological processes in various diseases. Because of these properties, they are considered to be promising biomarkers for the diagnosis and prognosis of various diseases and may contribute to the development of minimally invasive diagnostics and next generation therapies. The biocompatible nature of exosomes could enhance the stability and efficacy of imaging probes and therapeutics. Due to their potential use in clinical applications, exosomes have attracted much research attention on their roles in health and disease. To explore the use of exosomes in the biomedical arena, it is essential that the basic molecular mechanisms behind the transport and function of these vesicles are well-understood. Herein, we discuss the history, biogenesis, release, isolation, characterization, and biological functions of exosomes, as well as the factors influencing their biogenesis and their technical and biological challenges. We conclude this review with a discussion on the future perspectives of exosomes.

Role of exosomes in pathogenesis, progression, diagnosis and treatment of hepatocellular carcinoma

Exosomes are nanovesicles that may play a role in intercellular communication by acting as carriers of functional contents such as proteins, lipids, RNA molecules, and circulating DNA between cells. In addition, exosomes may play a potential role in immunosurveillance and tumor pathogenesis and progression. Recently, research has increasingly focused on the role of exosomes in hepatocellular carcinoma (HCC), the most common primary liver malignancy. In addition to their diagnostic value in HCC, exosomes are also involved in different mechanisms of HCC pathogenesis and progression including angiogenesis and immune escape. Moreover, exosomes have been demonstrated to change the tumor microenvironment to a less tolerogenic state, favoring immune response and tumor suppression. These results underline a practical and potentially feasible role of exosomes in the treatment of patients with HCC, both as a target and a vehicle for drug design. Future studies need to further elucidate the exact role and reliability of exosomes as screening, diagnosis, and treatment targets in patients with HCC. We herein review the data on emerging experimental and clinical studies that focused on the role of exosomes in the pathogenesis, progression, diagnosis, and therapy response of patients with HCC.

Tumor-derived exosomes: Implication in angiogenesis and antiangiogenesis cancer therapy

Tumor cells utilize different strategies to communicate with neighboring tissues for facilitating tumor progression and invasion, one of these strategies has been shown to be the release of exosomes. Exosomes are small nanovesicles secreted by all kind of cells in the body, especially cancer cells, and mediate cell to cell communications. Exosomes play an important role in cancer invasiveness by harboring various cargoes that could accelerate angiogenesis. Here first, we will present an overview of exosomes, their biology, and their function in the body. Then, we will focus on exosomes derived from tumor cells as tumor angiogenesis mediators with a particular emphasis on the underlying mechanisms in various cancer origins. Also, exosomes derived from stem cells and tumor-associated macrophages will be discussed in this regard. Finally, we will discuss the novel therapeutic strategies of exosomes as drug delivery vehicles against angiogenesis.

Exosomes in hepatocellular carcinoma: a new horizon

Exosomes are a class of extracellular vesicles released by multiple cells types including tumor cells, with a size range of 30-100 nm and a lipid bilayer membrane. Recently, the role of exosomes in cell-to-cell communication has been extensively studied, showed that exosomes can deliver their functional RNAs and proteins to recipient cells, impacting transcription and translation of recipient cells. Emerging evidence suggests that hepatocellular carcinoma (HCC) cell-derived exosomes can construct a fertile environment to support HCC cells proliferation, grow, invasion and metastasis, development of drug resistance. Circulating exosomes can be used as noninvasive biomarkers for early diagnosis, moreover as drug delivery vehicles, provide new insights into the treatment of HCC.

Current Progresses of Exosomes as Cancer Diagnostic and Prognostic Biomarkers

Cancer related exosomes are nano-size membrane vesicles that play important roles in tumor microenvironment. Emerging evidence indicates that exosomes can load unique cargoes, including proteins and nucleic acids that reflect the condition of tumor. Therefore, exosomes are being used as diagnostic and prognostic biomarkers for various cancers. In this review, we describe the current progresses of cancer related exosomes, including their biogenesis, molecular contents, biological functions, sources where they are derived from, and methods for their detection. We will also discuss the current exosomal biomarkers and the utilization of them for early diagnosis and prognostics in cancer.

Sialylation of vasorin by ST3Gal1 facilitates TGF-β1-mediated tumor angiogenesis and progression

ST3Gal1 is a key sialyltransferase which adds α2,3‐linked sialic acid to substrates and generates core 1 O‐glycan structure. Upregulation of ST3Gal1 has been associated with worse prognosis of breast cancer patients. However, the protein substrates of ST3Gal1 implicated in tumor progression remain elusive. In our study, we demonstrated that ST3GAL1‐silencing significantly reduced tumor growth along with a notable decrease in vascularity of MCF7 xenograft tumors. We identified vasorin (VASN) which was shown to bind TGF‐β1, as a potential candidate that links ST3Gal1 to angiogenesis. LC‐MS/MS analysis of VASN secreted from MCF7, revealed that more than 80% of its O‐glycans are sialyl‐3T and disialyl‐T. ST3GAL1‐silencing or desialylation of VASN by neuraminidase enhanced its binding to TGF‐β1 by 2‐ to 3‐fold and thereby dampening TGF‐β1 signaling and angiogenesis, as indicated by impaired tube formation of HUVECs, suppressed angiogenesis gene expression and reduced activation of Smad2 and Smad3 in HUVEC cells. Examination of 114 fresh primary breast cancer and their adjacent normal tissues showed that the expression levels of ST3Gal1 and TGFB1 were high in tumor part and the expression of two genes was positively correlated. Kaplan Meier survival analysis showed a significantly shorter relapse‐free survival for those with lower expression VASN, notably, the combination of low VASN with high ST3GAL1 yielded even higher risk of recurrence (p = 0.025, HR = 2.967, 95% CI = 1.14–7.67). Since TGF‐β1 is known to transcriptionally activate ST3Gal1, our findings illustrated a feedback regulatory loop in which TGF‐β1 upregulates ST3Gal1 to circumvent the negative impact of VASN.

What's new?

The addition of sialic acid to glycoproteins is dysregulated in many cancers, and enhanced expression of one key enzyme, the sialyltransferase ST3Gal1, is associated with poor prognosis. Here, the authors identified the membrane protein vasorin as a new ST3Gal1 substrate and connect it with TGF‐β1‐induced signaling and angiogenesis in breast cancer. As silencing of ST3Gal1 dampened TGF‐β1 signaling and suppressed angiogenesis, development of ST3Gal1 inhibitors might be clinically useful to improve the prognosis of breast cancer patients.

From Vascular Smooth Muscle Cells to Folliculogenesis: What About Vasorin?

First described in 1988, vasorin (VASN) is a transmembrane glycoprotein expressed during early mouse development, and with a less extent, in various organs and tissues (e.g., kidney, aorta, and brain) postnatally. Vasn KO mice die after 3 weeks of life from unknown cause(s). No human disease has been associated with variants of this gene so far, but VASN seems to be a potential biomarker for nephropathies and tumorigenesis. Its interactions with the TGF-β and Notch1 pathways offer the most serious assumptions regarding VASN functions. In this review, we will describe current knowledge about this glycoprotein and discuss its implication in various organ pathophysiology.

The biological functions of target genes in pan-cancers and cell lines were predicted by miR-375 microarray data from GEO database and bioinformatics

BACKGROUND

MicroRNA is endogenous non-coding small RNA that negative regulate and control gene expression, and increasing evidence links microRNA to oncogenesis and the pathogenesis of cancer. The goal of this study was to explore the potential molecular mechanism of miR-375 in various cancers.

METHODS

MiR-375 overexpression in different tumor cell lines was probed with microarray data from Gene Expression Omnibus (GEO). The common target genes of miR-375 were obtained by Robust Rank Aggregation (RRA), and identified by miRWalk2.0 software for target gene prediction. Additionally, we directed in silico analysis including Protein-Protein Interactions (PPI) analysis, gene ontology (GO) enrichment analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways annotations to provide a summary of the function of miR-375 in various carcinomas. Eventually, data was obtained from The Cancer Genome Atlas (TCGA) were utilized for a validation in 7 cancers.

RESULTS

The nine miR-375 related chips were acquired by the GEO data. The 5 down regulated genes came from 9 available microarray datasets, which overlapped with the potential target genes predicted by miRWalk2.0 software. The target genes were intensely enriched in amino acid biosynthetic and metabolic process from biological process (GO) and Cysteine and methionine metabolism (KEGG analysis). In view of these approaches, VASN, MAT2B, HERPUD1, TPAPPC6B and TAT are probably the most important miR-375 targets. In addition, miR-375 was negatively correlated with MAT2B, which was verified in 5 tumors of TCGA.

CONCLUSION

In summary, this study based on common target genes provides an innovative perspective for exploring the molecular mechanism of miR-375 in human tumors.

Differentially circulating exosomal microRNAs expression profiling in oral lichen planus

Oral lichen planus (OLP) is a common chronic inflammatory autoimmune disease with unclear etiology. The aim of the present study was to identify the expression profiles of circulating exosomal miRNAs, which have been shown to be potent stimulators of inflammatory and immune responses, in OLP patients. Plasma exosomes were isolated from the patients and healthy individuals, and RAE scoring system was used to evaluate the severity of OLP. Differentially deregulated exosomal miRNAs associated with inflammatory response and autoimmunity in OLP were identified by miScript^® miRNA PCR Array, and the results were confirmed by RT-PCR. The relationship between exosomal miRNAs and RAE scores was then analyzed, and bioinformatics analysis was used to predict the target genes and pathways of the differentially expressed exosomal miRNAs. Expression profiling showed that circulating exosomal miR-34a-5p and miR-130b-3p were upregulated, while miR-301b-3p was downregulated in OLP patients. Exosomal miR-34a-5p was positively correlated with the severity of OLP. Bioinformatics analysis revealed that the target genes of miR-34a-5p were mainly involved in regulation of gene expression, cell communication, signaling, and metabolic process, and modulated OLP progression through the PI3K/Akt signaling pathway. In conclusion, circulating exosomal miR-34a-5p could be a potential biomarker for evaluating the severity of OLP.

The functional role of exosome in hepatocellular carcinoma

PURPOSE

Hepatocellular carcinoma (HCC) is one of the most common cancers worldwide with limited therapeutic options. Exosome is a member of extracellular vesicles that can be released by different cells in liver to communicate with other cells. HCC development has been characterized by a dysfunction of exosome regulation through many molecular mechanisms. The aim of the present review is to summarize the literature on exosomes in HCC, their roles in hepatocarcinogenesis from liver disease, molecules exchange between tumor cells and neighboring cells, metastasis, chemoresistant, immunosuppression, early diagnose and therapy application.

METHODS

Literatures about HCC and exosomes from PubMed databases were reviewed in this article.

RESULTS

As our review described, exosomes can induce malignant transformation of liver disease via promoting viral diffusion and inflammation, exchange oncogenic factors between tumor cells, sustain tumor growth by neighboring stromal cells, play a important role in metastasis, trigger chemoresistance through transmitting long noncoding RNAs, stimulate immune activation as well as immune evasion, be utilized in biomarkers discovery and therapeutic options.

CONCLUSIONS

Available data suggested that exosomes may play an important role in HCC development. More studies on the way that exosomes mediated the HCC progression are needed to promote the clinical utilization of exosomes.

Exosomes in the Oncobiology, Diagnosis, and Therapy of Hepatic Carcinoma: A New Player of an Old Game

Exosomes are emerging as essential vehicles mediated cross-talk between different types of cells in tumor microenvironment. The extensive exploration of exosomes in hepatocellular carcinoma (HCC) enhances our comprehension of cancer biology referring to tumor growth, metastasis, immune evasion, and chemoresistance. Besides, the versatile roles of exosomes provide reasonable explanations for the propensity for liver metastasis of gastric cancer, pancreatic ductal adenocarcinoma, breast cancer, and colorectal cancer. The selective-enriched components, especially some specific proteins and noncoding RNAs in exosomes, have great potential as noninvasive biomarkers of HCC with high sensitivity and specificity. The characteristics of exosomes further inspire frontier research to interrupt intercellular malignant signals by controlling the biogenesis, release, or contents of exosomes.

Potential roles of tumor-derived exosomes in angiogenesis

INTRODUCTION

Tumor-derived exosomes (TEX) and their role in tumor progression by accelerating angiogenesis are of great current interest. A better understanding of the mechanisms underlying TEX-blood vessels cross-talk may lead to improvements in current diagnosis, prognosis and treatment of cancer. Areas covered: For solid tumors, an adequate blood supply is of critical importance for their development, growth and metastasis. TEX, virus-size vesicles which circulate freely throughout body fluids and accumulate in the tumor microenvironment (TME), have been recognized as a new contributor to angiogenesis. TEX serve as a communication system between the tumor and various normal cells and are responsible for functional reprogramming of these cells. The molecular and genetic cargos that TEX deliver to the recipient cells involved in angiogenesis promote its induction and progression. The targeted inhibition of TEX pro-angiogenic functions might be a novel therapeutic approach for control of tumor progression. Expert opinion: TEX circulating in body fluids of cancer patients carry a complex molecular and genetic cargo and are responsible for phenotypic and functional reprogramming of endothelial cells and other normal cells residing in the TME.

Vasorin: a newly identified regulator of ovarian folliculogenesis

Members of the TGF-β superfamily take part in the control of folliculogenesis. Vasorin (Vasn) is a newly identified negative regulator of TGF-β signaling whose possible involvement in ovarian physiology has never been studied. Here, we demonstrate that Vasn is expressed in the ovary by somatic cells of follicles, and that its expression is up-regulated by LH. We established a conditional knockout (cKO) mouse model in which Vasn is deleted specifically in granulosa cells of growing follicles from the secondary stage onwards. Using this model, we show that, upon hormonal stimulation, follicle ovulation size is almost 2-fold higher. This enhanced ovulatory response is associated with overactivation of the TGF-β signaling pathway and a lower number of atretic antral follicles. Of importance, we demonstrate that the number of primordial follicles is reduced in prepubertal cKO mouse ovaries, which suggests that the production of VASN by growing follicles protects the ovarian reserve. Finally, analysis of systemic KO mice revealed that the ovarian reserve is almost 2.5-fold higher, which implies that Vasn may also play a role in primordial follicle formation. Overall, our findings reveal that Vasn is a new regulator that exerts an effect on several key ovarian functions, including folliculogenesis, maintenance of the ovarian reserve, and ovulation.-Rimon-Dahari, N., Heinemann-Yerushalmi, L., Hadas, R., Kalich-Philosoph, L., Ketter, D., Nevo, N., Galiani, D., Dekel, N. Vasorin: a newly identified regulator of ovarian folliculogenesis.

Identification of Functional mimotopes of human Vasorin Ectodomain by Biopanning

Human vasorin (VASN) as a type I transmembrane protein, is a potential biomarker of hepatocellular carcinoma, which could expedite HepG2 cell proliferation and migration significantly in vitro. The ectodomain of VASN was proteolytically released to generate soluble VASN (sVASN), which was validated to be the active form. Among several monoclonal antibodies produced against sVASN, the clone V21 was found to bind with the recombinant human sVASN (rhsVASN) with the highest affinity and specificity, and also have inhibitory effects on proliferation and migration of HepG2 cells. Hence the phage-displayed peptide library was screened against the antibody V21. The positive phage clones were isolated and sequenced, and one unique consensus motifs was obtained. The result of sequence alignment showed that the conserved motif had similarity to VASN(Cys432-Cys441), embedded in the epidermal growth factor (EGF)-like domain. The synthetic mimotope peptide V21P1 and V21P2 were confirmed to bind with V21 and could compete with rhsVASN in ELISA assay. And they could also almost completely reverse the inhibitory effect of V21 on HepG2 migration and proliferation. Furthermore, the antibodies produced against V21P1 were able to bind not only with the peptide V21P1, but also with rhsVASN and the natural VASN from HepG2 cell. Our results showed that V21 seemed to be a functional antibody. The mimotopes toward V21 might mimic the functional domain of VASN, which would be helpful to exploit VASN functions and act as a candidate target for developing therapeutic antibodies against VASN.

The role of extracellular vesicles in mediating progression, metastasis and potential treatment of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a major cause of cancer-related death worldwide. As vectors for intercellular information exchange, the potential role of extracellular vesicles (EVs) in HCC formation, progression and therapy has been widely investigated. In this review, we explore the current status of the researches in this field. Altogether there is undeniable evidence that EVs play a crucial role in HCC development, metastasis. Moreover, EVs have shown great potential as drug delivery systems (DDSs) for the treatment of HCC. Exosomal miRNAs derived from HCC cells can enhance transformed cell growth in recipient cells by modulating the expression of transforming growth factor-β activated kinase-1(TAK1) and downstream signaling molecules. Furthermore, vacuolar protein sortin 4 homolog A(VPS4A) and insulin-like growth factor(IGF)-1 regulate exosome-mediated miRNAs transfer. Immune cells- derived EVs containing integrin αMβ2 or CD147 may facilitate HCC metastasis. In addition, EVs-mediated shuttle of long non-coding RNAs (lncRNAs), specifically linc- VLDLR and linc-ROR promote chemoresistance of malignant cells. Heat shock proteins (HSPs)-harboring exosomes derived from HCC tumor cells increase the antitumor effect of natural killer (NK) cells, thus enhancing HCC immunotherapy. Indeed, inhibition of HCC tumor growth has been associated with tumor cell-derived exosomes (TEX)-pulsed dentritic cells (DCs). Exosomes are also essential in liver metastasis during colorectal carcinoma (CRC) and pancreatic ductal adenocarcinomas (PDAC). Therefore, as nucleic acid and drug delivery vehicles, EVs show a tremendous potential for effective treatment against HCC.

Exosomes: small vesicles with big roles in hepatocellular carcinoma

Despite improvements in the diagnosis and treatment of hepatocellular carcinoma (HCC), the prognosis is still poor. Pioneering work has demonstrated a potential role for tumour cell-derived exosomes (TEXs) in HCC. TEXs can mediate immune responses, antigen presentation and intracellular communication by serving as vehicles for the transfer of proteins, viruses, lipids and RNA between cells. An improved understanding of the roles played by exosomes could lead to a powerful new strategy for preventing and treating HCC. In this review, we summarise current understanding on the topic. The literature points to two faces of TEXs in HCC: 1) They can promote invasion, metastasis, immune evasion and modulation and 2) they can act as diagnostic and prognostic biomarkers, and can be used in anti-cancer drug resistance and immunotherapy in the future.

Role of exosomes and exosomal microRNAs in hepatocellular carcinoma: Potential in diagnosis and antitumour treatments (Review)

Communication between hepatocellular carcinoma (HCC) cells and their environment is essential for the development and progression of HCC. Exosomes, which are microvesicles secreted by a number of cell types, are carriers of intercellular information and regulate the tumour microenvironment. Studies have demonstrated that exosomes are involved in the communication between HCC cells, endothelial cells and stem cells, and that they serve important roles in the metastasis and invasion, immune evasion and immunotherapy of HCC. In addition, the mechanism of HCC-derived exosome-mediated microRNA (miRNA) transfer is important in the environmental modulation of HCC growth and progression. As exosomes can be used for detecting and monitoring HCC, they can potentially serve as specific biomarkers for early-stage tumours and the tumour metastasis of HCC. Moreover, mesenchymal stem cell-derived exosomes can be transfected with miRNAs to inhibit HCC development. Therefore, as nucleic acid delivery vehicles, exosomes show a tremendous potential for effective treatment against HCC. In the present review, recent advances in our understanding of the source, composition and function of exosomes in HCC, and their potential value in the early diagnosis and treatment of HCC, are summarized.

The role of exosomes in cancer metastasis

Exosomes are small membrane vesicles with a size ranging from 40 to 100nm. They can serve as functional mediators in cell interaction leading to cancer metastasis. Metastasis is a complex multistep process of cancer cell invasion, survival in blood vessels, attachment to and colonization of the host organ. Exosomes influence every step of this cascade and can be targeted by oncological treatment. This review highlights the role of exosomes in the various steps of the metastatic cascade and how exosome dependent pathways can be targeted as therapeutic approach or used for liquid biopsies.

Genomic analysis reveals selection in Chinese native black pig

Identification of genomic signatures that help reveal mechanisms underlying desirable traits in domesticated pigs is of significant biological, agricultural and medical importance. To identify the genomic footprints left by selection during domestication of the Enshi black pig, a typical native and meat-lard breed in China, we generated about 72-fold coverage of the pig genome using pools of genomic DNA representing three different populations of Enshi black pigs from three different locations. Combining this data with the available whole genomes of 13 Chinese wild boars, we identified 417 protein-coding genes embedded in the selected regions of Enshi black pigs. These genes are mainly involved in developmental and metabolic processes, response to stimulus, and other biological processes. Signatures of selection were detected in genes involved in body size and immunity (RPS10 and VASN), lipid metabolism (GSK3), male fertility (INSL6) and developmental processes (TBX19). These findings provide a window into the potential genetic mechanism underlying development of desirable phenotypes in Enshi black pigs during domestication and subsequent artificial selection. Thus, our results illustrate how domestication has shaped patterns of genetic variation in Enshi black pigs and provide valuable genetic resources that enable effective use of pigs in agricultural production.

Fibrogenic Signaling Is Suppressed in Hepatic Stellate Cells through Targeting of Connective Tissue Growth Factor (CCN2) by Cellular or Exosomal MicroRNA-199a-5p

Pathways of liver fibrosis are controlled by connective tissue growth factor (CCN2). In this study, CCN2 was identified as a target of miR-199a-5p, which was principally expressed in quiescent mouse hepatic stellate cells (HSCs) and directly suppressed production of CCN2. Up-regulated CCN2 expression in fibrotic mouse livers or in activated primary mouse HSCs was associated with miR-199a-5p down-regulation. MiR-199a-5p in quiescent mouse HSCs inhibited the activity of a wild-type CCN2 3' untranslated region (3'-UTR) but not of a mutant CCN2 3'-UTR lacking the miR-199a-5p-binding site. In activated mouse HSCs, CCN2, α-smooth muscle actin, and collagen 1(α1) were suppressed by a miR-199a-5p mimic, whereas in quiescent mouse HSCs, the inhibited CCN2 3'-UTR activity was blocked by a miR-199a-5p antagomir. CCN2 3'-UTR activity in human HSCs was reduced by a miR-199a-5p mimic. MiR-199a-5p was present at higher levels in exosomes from quiescent versus activated HSCs. MiR-199a-5p-containing exosomes were shuttled from quiescent mouse HSCs to activated mouse HSCs in which CCN2 3'-UTR activity was then suppressed. Exosomes from quiescent HSCs caused miR-199a-5p-dependent inhibition of CCN2, α-smooth muscle actin, or collagen 1(α1) in activated HSCs in vitro and bound to activated HSCs in vivo. Thus, CCN2 suppression by miR-199a-5p accounts, in part, for low-level fibrogenic gene expression in quiescent HSCs and causes dampened gene expression in activated HSCs after horizontal transfer of miR-199a-5p in exosomes from quiescent HSCs.