Effect of exosomal miRNA on cancer biology and clinical applications

Exosomes: From Potential Culprits to New Therapeutic Promise in the Setting of Cardiac Fibrosis

Fibrosis is a significant global health problem associated with many inflammatory and degenerative diseases affecting multiple organs, individually or simultaneously. Fibrosis develops when extracellular matrix (ECM) remodeling becomes excessive or uncontrolled and is associated with nearly all forms of heart disease. Cardiac fibroblasts and myofibroblasts are the main effectors of ECM deposition and scar formation. The heart is a complex multicellular organ, where the various resident cell types communicate between themselves and with cells of the blood and immune systems. Exosomes, which are small extracellular vesicles, (EVs), contribute to cell-to-cell communication and their pathophysiological relevance and therapeutic potential is emerging. Here, we will critically review the role of endogenous exosomes as possible fibrosis mediators and discuss the possibility of using stem cell-derived and/or engineered exosomes as anti-fibrotic agents.

m6A demethylase ALKBH5 inhibits tumor growth and metastasis by reducing YTHDFs-mediated YAP expression and inhibiting miR-107/LATS2-mediated YAP activity in NSCLC

BACKGROUND

The importance of mRNA methylation erased by ALKBH5 in mRNA biogenesis, decay, and translation control is an emerging research focus. Ectopically activated YAP is associated with the development of many human cancers. However, the mechanism whereby ALKBH5 regulates YAP expression and activity to inhibit NSCLC tumor growth and metastasis is not clear.

METHODS

Protein and transcript interactions were analyzed in normal lung cell and NSCLC cells. Gene expression was evaluated by qPCR and reporter assays. Protein levels were determined by immunochemical approaches. Nucleic acid interactions and status were analyzed by immunoprecipitation. Cell behavior was analyzed by standard biochemical tests. The m⁶A modification was analyzed by MeRIP.

RESULTS

Our results show that YAP expression is negatively correlated with ALKBH5 expression and plays an opposite role in the regulation of cellular proliferation, invasion, migration, and EMT of NSCLC cells. ALKBH5 reduced m⁶A modification of YAP. YTHDF3 combined YAP pre-mRNA depending on m⁶A modification. YTHDF1 and YTHDF2 competitively interacted with YTHDF3 in an m⁶A-independent manner to regulate YAP expression. YTHDF2 facilitated YAP mRNA decay via the AGO2 system, whereas YTHDF1 promoted YAP mRNA translation by interacting with eIF3a; both these activities are regulated by m⁶A modification. Furthermore, ALKBH5 decreased YAP activity by regulating miR-107/LATS2 axis in an HuR-dependent manner. Further, ALKBH5 inhibited tumor growth and metastasis in vivo by reducing the expression and activity of YAP.

CONCLUSIONS

The presented findings suggest m⁶A demethylase ALKBH5 inhibits tumor growth and metastasis by reducing YTHDFs-mediated YAP expression and inhibiting miR-107/LATS2-mediated YAP activity in NSCLC. Moreover, effective inhibition of m⁶A modification of ALKBH5 might constitute a potential treatment strategy for lung cancer.

Integrated characterization and validation of the prognostic significance of microRNA-200s in colorectal cancer

Background

Accumulating evidence has demonstrated that microRNA-200s (miR-200a, miR-200b and miR-200c) could serve as promising molecular biomarkers for cancer prognosis. Nevertheless, the associations between miR-200s expression and colorectal cancer (CRC) prognosis remain controversial.

Methods

We applied two mainstream approaches combining meta-analysis and bioinformatics analysis to answer whether miR-200s were associated with the prognosis of CRC patients and why miR-200s could be used as prognostic biomarkers for CRC.

Results

Consequently, low expression of miR-200s was associated with unfavorable overall survival (OS) in CRC patients (HR: 1.09; 95% CI 1.01–1.17; P = 0.025). According to the subgroup analysis, the prognostic role of miR-200s was more significant for tissue samples, large samples, American patients and miR-200a subgroups. Then the target genes of miR-200s were predicted and applied for functional enrichment analyses. The results showed that the target genes of miR-200s were mainly enriched into some vital ontology subjects such as regulation ability, key cell structures and binding function. Moreover, a series of important signaling pathways were identified, which were significantly linked with the initiation and progression of CRC. Additionally, a protein‑protein interaction (PPI) network of miR-200s targets was constructed to screen hub genes and modules. The identified hub genes and modules were validated to be highly involved in the occurrence and development of CRC.

Conclusions

Current evidences revealed that miR-200s could be promising biomarkers for CRC prognosis. However, the findings still need to be validated with more larger-scale prospective studies and biological experiments before miR-200s could be applied into clinical application.

Exosomal miR-103-3p from LPS-activated THP-1 macrophage contributes to the activation of hepatic stellate cells

Hepatic fibrosis occurs during chronic hepatic injury and is involved in hepatic stellate cells (HSCs) activated by several types of immune cells. Among the immune cells, hepatic macrophages and their crosstalk with HSCs play a vital role in all stages of hepatic fibrosis. Exosomes, which are 30-150 nm lipid bilayer vehicles, can transfer specific lipid, nucleic acids, proteins, and other bioactive molecules. Exosomes can act as good communication between macrophages and HSCs. Herein, we investigated the role of exosomes between THP-1 macrophage and HSCs in the progression of liver fibrosis. Exosomes originating from lipopolysaccharide (LPS)-treated THP-1 macrophages promoted HSCs proliferation and induced the increased expression of fibrotic genes. LPS could alter the miRNA profile in exosomes secreted from THP-1 macrophages. The changed miR-103-3p in exosomes could promote HSCs proliferation and activation by targeting Krüppel-like factor 4 (KLF4) and it plays important roles in the crosstalk between THP-1 macrophages and HSCs during the progression of liver fibrosis. Moreover, miR-103-3p in serum exosomes from liver fibrosis patients could be a biomarker for liver fibrosis. Therefore, exosomes may have important roles in the crosstalk between macrophage and HSCs in the progression of chronic liver diseases.

MiR-21, EGFR and PTEN in non-small cell lung cancer: an in situ hybridisation and immunohistochemistry study

AIMS

To analyse microRNA (miR)-21 distribution and expression at the cellular level in non-small cell lung cancer (NSCLC). MiR-21 is an oncogenic microRNA overexpressed in NSCLC. In previous studies, overexpression of miR-21 was evaluated from the tumour bulk by quantitative reverse transcription PCR with results expressed on average across the entire cell population.

METHODS

We used in situ hybridisation and immunohistochemistry to assess the correlation between miR-21 levels and the expression of markers that may be possible targets (epidermal growth factor reaction) or may be involved in its upregulation (phosphatase and tensin homolog (PTEN), p53). The Pearson's χ² tests was used to assess correlation with clinicopathological data and with miR-21 expression both in tumour and tumour stroma.

RESULTS

Cytoplasmic staining and expression of Mir-21 were detected in the tumours and in associated stromal cells. Expression was highest in the stroma immediately surrounding the tumour cells and decreased as the distance from the tumour increased. No expression of miR-21 was found in normal lung parenchyma and a significant association was found between tumour localised miR-21 and PTEN.

CONCLUSIONS

Presence of miR-21 in both cell tumour and stromal compartments of NSCLC and the relationship with PTEN confirms miR-21 as a microenvironment signalling molecule, possibly inducing epithelial mesenchymal transition and invasion by targeting PTEN in the stromal compartment possibly through exosomal transport. In situ immunohistochemical studies such as ours may help shed light on the complex interactions between miRNAs and its role in NSCLC biology.

Exosomal Long NonCoding Rnas as Cancer Biomarkers and Therapeutic Targets

Extensive study of extracellular vesicles began about ten years ago. Exosomes are extracellular membrane vesicles 30–100 nm in diameter secreted by various types of cells and present in most biological fluids. For a long time they were considered non-functional cellular components. However, it has been proven that they serve as a means of intercellular exchange of information. They can move bioactive molecules such as proteins, lipids, RNA, and DNA. Several studies have shown that their contents, including proteins and non-coding nucleic acids, may be of particular interest as biomarkers of diseases. The most promising of all these molecules are non-coding RNAs (ncRNAs), including microRNAs and long non-coding RNAs (lncRNAs). LncRNAs are a large group of non-coding RNAs (ncRNAs) longer than 200 nucleotides. As regulatory factors lncRNAs play an important role in complex cellular processes, such as apoptosis, growth, differentiation, proliferation, etc. Despite many advances in diagnosis and treatment (surgery, radiation therapy, chemotherapy), cancer remains one of the most important public healthcare problems worldwide. Every day brings a better understanding of the role of exosomes in the development of cancer and metastases. Liquid biopsy has been developed as a method for the detection of cancer at an early stage. This is a series of minimally invasive tests of bodily fluids offering the advantage of real-time tracking of the tumour development. In fact, circulating exosomal lncRNAs have been found to be closely linked to processes of oncogenesis, metastasis and treatment. In this paper we review current studies into the functional role of exosomal lncRNAs in cancer and discuss their potential clinical use as diagnostic biomarkers and therapeutic targets for cancer.

Exosome-encapsulated miRNAs contribute to CXCL12/CXCR4-induced liver metastasis of colorectal cancer by enhancing M2 polarization of macrophages

Tumor-associated macrophages (TAMs) are important immunocytes associated with cancer metastasis. However, whether TAMs play a dominant role in mediating CXCL12/CXCR4-induced liver metastasis of colorectal cancer (CRC) remains unexplored. Herein, we found that CD206⁺ TAMs, which infiltrated at the invasive front, were correlated with CXCR4 expression and liver metastasis of CRC in clinical specimens. Several miRNAs (miR-25-3p, miR-130b-3p, miR-425-5p), upregulated in CRC cells by activation of the CXCL12/CXCR4 axis, could be transferred to macrophages via exosomes. These exosomal miRNAs induced M2 polarization of macrophages by regulating PTEN through activation of PI3K/Akt signaling pathway. In turn, M2 polarized macrophages promoted cancer metastasis by enhancing epithelial-mesenchymal transition (EMT) and secreting vascular endothelial growth factor (VEGF). Co-culture of CRC cells with macrophages transfected with these miRNAs or treated with exosomes enhanced their metastatic capacity both in vitro and in vivo. Clinically, the serum levels of exosomal miR-25-3p, miR-130b-3p and miR-425-5p were correlated with progression and metastasis of CRC. In conclusion, these results reveal a crucial role of exosomal miRNAs in mediating the crosstalk between CXCR4 overexpressing cancer cells and TAMs, providing potential therapeutic targets for circumventing liver metastasis of CRC.

Enhancing the Bystander and Abscopal Effects to Improve Radiotherapy Outcomes

In this paper, we summarize published articles and experiences related to the attempt to improve radiotherapy outcomes and, thus, to personalize the radiation treatment according to the individual characteristics of each patient. The evolution of ideas and the study of successively published data have led us to envisage new biophysical models for the interpretation of tumor and healthy normal tissue response to radiation. In the development of the model, we have shown that when mesenchymal stem cells (MSCs) and radiotherapy are administered simultaneously in experimental radiotherapy on xenotumors implanted in a murine model, the results of the treatment show the existence of a synergic mechanism that is able to enhance the local and systemic actions of the radiation both on the treated tumor and on its possible metastasis. We are convinced that, due to the physical hallmarks that characterize the neoplastic tissues, the physical-chemical tropism of MSCs, and the widespread functions of macromolecules, proteins, and exosomes released from activated MSCs, the combination of radiotherapy plus MSCs used intratumorally has the effect of counteracting the pro-tumorigenic and pro-metastatic signals that contribute to the growth, spread, and resistance of the tumor cells. Therefore, we have concluded that MSCs are appropriate for therapeutic use in a clinical trial for rectal cancer combined with radiotherapy, which we are going to start in the near future.

Natural Killer Cell-Derived Exosomal miR-3607-3p Inhibits Pancreatic Cancer Progression by Targeting IL-26

Increasing evidences have suggested that natural killer (NK) cells in the tumor microenvironment are involved in the regulation of cancer development. However, the potential biological roles and regulatory mechanisms of NK cells in pancreatic cancer (PC) remain unclear. Co-culture system of NK cells with PC cells is used to test the ability of cancer cell proliferation, migration and invasion both in vitro and in vivo. And tail vein intravenous transfer was used to test metastasis in vivo. Meanwhile, extracellular vesicles (EVs) were separated and examined. Furthermore, reporter assay and Biotin-RNA pull down assay were performed to verify the interaction between molecules. NK cells can inhibit the malignant transformation of co-cultured PC cells both in vivo and in vitro, which requires miR-3607-3p. miR-3607-3p is found enriched in the EVs of NK cells and transmitted to PC cells, and low level of miR-3607-3p predicts poor prognosis in PC patients. It can also inhibit proliferation, migration and invasion of PC cells in vitro. Importantly, IL-26 is found to be a direct target of miR-3607-3p in PC cells. miR-3607-3p enriched in EVs derived from NK cells can inhibit the malignant transformation of PC probably through directly targeting of IL-26.

Endosomal TLR-8 Senses microRNA-1294 Resulting in the Production of NFḱB Dependent Cytokines

The primary function of toll-like receptor 8 (TLR-8) is the detection of viruses and other microbial pathogens. Recent evidence suggests that TLR-8 also senses host microRNAs (miRNAs) and implicate TLR-8 in autoimmune disorders. This study examined the interaction between miR-1294 and TLR-8. We first performed a BLAST search to identify miRNAs with the same sequences as two core motifs of miR-1294. Next, we examined NFḱB activation induced by the binding of miR-1294 mimic to endosomal TLR-8. HEK-Blue™ hTLR-8 cells (Invivogen), a HEK293 cell line co-transfected with human TLR-8 gene, were incubated with miR-1294 mimic. A TLR-8 agonist ssRNA40, was used as a positive control. Using the same experimental set up, we also examined the effects of miR-1294 and its two core motifs (Integrated DNA Technologies) on IL-8, IL-1β, and TNFα. Data were analyzed using t-test or one-way ANOVA and Dunnets post-hoc test. Using miRCarta we identified 29 other mature human miRNAs or their precursors which contain the same core motifs as miR-1294. Our data show that miR-1294 activates NFḱB in cells expressing TLR-8 (p < 0.05). miR-1294, and its core motifs induce expression of IL-8, IL-1β, and TNFα via TLR8 activation (p < 0.05). This constitutes a novel mechanism by which endosomal TLR-8 senses host miRNAs resulting in the release of pro-inflammatory cytokines and thus potentially contributing to autoimmune disorders.

circRNAs and Exosomes: A Mysterious Frontier for Human Cancer

Exosomes are nano-sized membrane-bound vesicles and contain active substances (DNA, noncoding RNA [ncRNA], protein), which provide a novel method of transferring effector messages between cells. Circular RNAs (circRNAs), a kind of ncRNA, have attracted increasing attention over the last decade given advances in whole-genome and transcriptome sequencing technologies. It has become increasingly clear that circRNAs regulate gene expression through various actions and play diverse roles in many fields of human cancer biology. Notably, several studies reported that circRNAs are enriched in exosomes and that exosomal circRNAs play an important role in cancer biology. Exosomal circRNAs can be taken up by neighboring or distant cells and affect many aspects of physiological and pathological conditions of the recipient cells, potentially promoting cell communication and tumor metastasis. Herein, we briefly review the molecular mechanisms of circRNAs and recent findings regarding exosomal circRNAs, and highlight the specific roles of exosomal circRNAs in human cancer.

miR-1305 Inhibits The Progression Of Non-Small Cell Lung Cancer By Regulating MDM2

Background

Increasing evidence has suggested the critical implication of microRNAs (miRNAs) in the initiation and progression of non-small cell lung cancer (NSCLC). Previous studies have shown the tumor-suppressive function of miR-1305 in cancer; however, the role of miR-1305 in NSCLC has not been fully understood.

Methods

The expression of miR-1305 in NSCLC was detected by RT-qPCR. The influence of miR-1305 on the growth of NSCLC cells was determined via Cell Counting Kit 8 (CCK-8), colony formation and FACS analysis. The targets of miR-1305 were predicted with the miRDB database. Luciferase reporter assay was performed to investigate the binding between miR-1305 and 3ʹ-UTR of MDM2. Western blot was applied to check the expression of MDM2 with miR-1305.

Results

Here, we found that miR-1305 was down-regulated in NSCLC tissues and cell lines. Decreased miR-1305 was significantly correlated with the metastasis and poor prognostics of NSCLC patients. Overexpression of miR-1305 inhibited the proliferation and migration and promoted the apoptosis of NSCLC cells. Bioinformatics and luciferase assay uncovered that the mouse/murine double minute 2 (MDM2) was a target of miR-1305. miR-1305 bound the 3ʹ-untranslated region (UTR) of MDM2 and decreased the expression of MDM2 in NSCLC cells. As MDM2 was a negative regulator of p53, decreased MDM2 by miR-1305 up-regulated the abundance of p53 in NSCLC cells. Restoration of MDM2 markedly attenuated the suppressive role of miR-1305 in the proliferation and migration of NSCLC cells.

Conclusion

The findings provided novel mechanism of miR-1305/MDM2 signaling in regulating the progression of NSCLC, suggesting miR-1305 as a promising target for the treatment of NSCLC.

Extracellular Vesicles in Modifying the Effects of Ionizing Radiation

Extracellular vesicles (EVs) are membrane-coated nanovesicles actively secreted by almost all cell types. EVs can travel long distances within the body, being finally taken up by the target cells, transferring information from one cell to another, thus influencing their behavior. The cargo of EVs comprises of nucleic acids, lipids, and proteins derived from the cell of origin, thereby it is cell-type specific; moreover, it differs between diseased and normal cells. Several studies have shown that EVs have a role in tumor formation and prognosis. It was also demonstrated that ionizing radiation can alter the cargo of EVs. EVs, in turn can modulate radiation responses and they play a role in radiation-induced bystander effects. Due to their biocompatibility and selective targeting, EVs are suitable nanocarrier candidates of drugs in various diseases, including cancer. Furthermore, the cargo of EVs can be engineered, and in this way they can be designed to carry certain genes or even drugs, similar to synthetic nanoparticles. In this review, we describe the biological characteristics of EVs, focusing on the recent efforts to use EVs as nanocarriers in oncology, the effects of EVs in radiation therapy, highlighting the possibilities to use EVs as nanocarriers to modulate radiation effects in clinical applications.

Plasma miR-30a-5p as an early novel noninvasive diagnostic and prognostic biomarker for lung cancer

Aim: Circulation miRNAs have become increasingly appreciated in the diagnosis and prognosis of lung cancer. This study aims to identify and evaluate plasma miRNA-30a-5p as an early noninvasive biomarker for the diagnosis and prognosis of lung cancer. Pateints & methods: Expression levels of plasma miRNA 30a-5p were measured by quantitative real-time PCR. Receiver operating characteristic analysis and area under the curve were used to differentiate malignant from benign tumors and from healthy controls. Kaplan-Meier curves and Cox regression were used to determine survival and prognosis. Results: Our results suggest that the level of miRNA-30a-5p in plasma might be a considerable early novel noninvasive diagnostic and prognostic biomarker for lung cancer. Conclusion: Prospective studies must be performed to confirm this new early novel noninvasive diagnostic and prognostic biomarker for lung cancer.

miR-665 promotes the progression of gastric adenocarcinoma via elevating FAK activation through targeting SOCS3 and is negatively regulated by lncRNA MEG3

Studies have found that miR-665 acted as a tumor suppressor or an oncogene in different malignancies. miR-665 expression was elevated in gastric adenocarcinoma tissues; however, its role and mechanism in this disease are not fully clarified. The expression of miR-665 and its target gene was detected in human gastric adenocarcinoma tissues and cells. Moreover, we analyzed the effects of miR-665 on the proliferation, migration, and epithelial-mesenchymal transition (EMT) of gastric adenocarcinoma cells as well as tumor growth in vivo. The mechanisms of miR-665 in gastric adenocarcinoma were investigated by using molecular biology techniques. We found miR-665 was upregulated and suppressor of cytokine signaling 3 (SOCS3) was downregulated in gastric adenocarcinoma tissues and cells. Elevated miR-665 was positively correlated with tumor size, lymph node metastasis, invasion depth, TNM stage, and poor differentiation in gastric adenocarcinoma patients. Overexpression of miR-665 promoted, whereas knockdown of miR-665 suppressed the proliferation, migration, and EMT of gastric adenocarcinoma cells. Furthermore, we demonstrated that miR-665 functioned through targeting SOCS3, followed by activation of the FAK/Src signaling pathway in gastric adenocarcinoma cells. miR-665 antagomir inhibited tumor growth as well as the activation of the FAK/Src pathway but increased SOCS3 expression in nude mice. In addition, miR-665 expression was negatively regulated by long noncoding RNA maternally expressed gene 3 (MEG3). In conclusion, miR-665 acted as an oncogene in gastric adenocarcinoma by inhibiting SOCS3 followed by activation of the FAK/Src pathway and it was negatively modulated by MEG3. miR-665 may be a promising therapeutic target for the treatment of gastric adenocarcinoma.

Potential Therapeutic Roles of Exosomes in Multiple Myeloma: A Systematic Review

Multiple myeloma (MM) is the second most prevalent hematological malignancy. In spite of the remarkable progress in understanding the biology and therapy of MM, curing this disease remains difficult, which calls for more effective treatment strategies. As vital communicators between different cells, exosomes have been verified to be crucial to cancer diagnosis, treatment, and prognosis. Exosomes in MM patients show a different expression profile compared with those in healthy individuals. In this review, we summarize potential therapy roles exosomes may play in MM. The specific expression of certain components in exosomes may provide therapeutic targets. Moreover, tumor-derived exosomes and their modified products can be developed into vaccines for anti-tumor immunity. In addition, the natural nano structure of exosomes makes them excellent carriers for drug delivery. Thus, a more rigorous investigation into exosomes will pave the way for novel tumor therapies in MM patients.

Epigenetic Drugs for Cancer and microRNAs: A Focus on Histone Deacetylase Inhibitors

Over recent decades, it has become clear that epigenetic abnormalities are involved in the hallmarks of cancer. Histone modifications, such as acetylation, play a crucial role in cancer development and progression, by regulating gene expression, such as for oncogenes or tumor suppressor genes. Therefore, histone deacetylase inhibitors (HDACi) have recently shown efficacy against both hematological and solid cancers. Designed to target histone deacetylases (HDAC), these drugs can modify the expression pattern of numerous genes including those coding for micro-RNAs (miRNA). miRNAs are small non-coding RNAs that regulate gene expression by targeting messenger RNA. Current research has found that miRNAs from a tumor can be investigated in the tumor itself, as well as in patient body fluids. In this review, we summarized current knowledge about HDAC and HDACi in several cancers, and described their impact on miRNA expression. We discuss briefly how circulating miRNAs may be used as biomarkers of HDACi response and used to investigate response to treatment.

MicroRNA-27a (miR-27a) in Solid Tumors: A Review Based on Mechanisms and Clinical Observations

MicroRNAs (miRNAs) are a family of highly conserved, non-coding single-stranded RNAs transcribed as ~70 nucleotide precursors to an 18–22 nucleotide product (1). miRNAs can silence their homologous target genes at the post-transcriptional level, and these genes have been revealed to play an important role in tumorigenesis, invasion and metastasis (2). MicroRNA-27a (miR-27a), transcripted by miR-27a gene, has proved to implicate with many kinds of solid tumors, showing potential as a useful biomarker or drug target for clinical application. However, even though miR-27a has been reported in many cancers, the mechanism and signal pathways of miR-27 in oncogenesis, invasion, and metastasis are still obscure. Moreover, recent studies show that miR-27a pays an important role in epithelial-mesenchymal-transition, regulating tumor immune response, and chemoresistance. In this review, we summarize the current literature, demonstrate the established link between miR-27a and tumorigenesis, and focus on recently identified mechanisms. The review also aims to demonstrate the potential of miR-27a as a diagnostic and/or prognostic biomarker in solid tumors and to discuss the possibilities of targeted therapy and drug design.

3D cell culture stimulates the secretion of in vivo like extracellular vesicles

For studying cellular communications ex-vivo, a two-dimensional (2D) cell culture model is currently used as the “gold standard”. 2D culture models are also widely used in the study of RNA expression profiles from tumor cells secreted extracellular vesicles (EVs) for tumor biomarker discovery. Although the 2D culture system is simple and easily accessible, the culture environment is unable to represent in vivo extracellular matrix (ECM) microenvironment. Our study observed that 2D- culture derived EVs showed significantly different profiles in terms of secretion dynamics and essential signaling molecular contents (RNAs and DNAs), when compared to the three-dimensional (3D) culture derived EVs. By performing small RNA next-generation sequencing (NGS) analysis of cervical cancer cells and their EVs compared with cervical cancer patient plasma EV-derived small RNAs, we observed that 3D- culture derived EV small RNAs differ from their parent cell small RNA profile which may indicate a specific sorting process. Most importantly, the 3D- culture derived EV small RNA profile exhibited a much higher similarity (~96%) to in vivo circulating EVs derived from cervical cancer patient plasma. However, 2D- culture derived EV small RNA profile correlated better with only their parent cells cultured in 2D. On the other hand, DNA sequencing analysis suggests that culture and growth conditions do not affect the genomic information carried by EV secretion. This work also suggests that tackling EV molecular alterations secreted into interstitial fluids can provide an alternative, non-invasive approach for investigating 3D tissue behaviors at the molecular precision. This work could serve as a foundation for building precise models employed in mimicking in vivo tissue system with EVs as the molecular indicators or transporters. Such models could be used for investigating tumor biomarkers, drug screening, and understanding tumor progression and metastasis.

MicroRNA biogenesis, gene silencing mechanisms and role in breast, ovarian and prostate cancer

Micro-ribonucleic acids (miRNAs) are important class of short regulatory RNA molecules involved in regulation of several essential biological processes. In addition to Dicer and Drosha, over the past few years several other gene products are discovered that regulates miRNA biogenesis pathways. Similarly, various models of molecular mechanisms underlying miRNA mediated gene silencing have been uncovered through which miRNA contribute in diverse physiological and pathological processes. Dysregulated miRNA expression has been reported in many cancers manifesting tumor suppressive or oncogenic role. In this review, critical overview of recent findings in miRNA biogenesis, silencing mechanisms and specifically the role of miRNA in breast, ovarian and prostate cancer will be described. Recent advancements in miRNA research summarized in this review will enhance the molecular understanding of miRNA biogenesis and mechanism of action. Also, role of miRNAs in pathogenesis of breast, ovarian and prostate cancer will provide the insights for the use of miRNAs as biomarker or therapeutic agents for the cancers.

Tumor-derived exosomes, myeloid-derived suppressor cells, and tumor microenvironment

Plenty of immune cells infiltrate into the tumor microenvironment (TME) during tumor progression, in which myeloid-derived suppressor cells (MDSCs) represent a heterogeneous population of immature myeloid cells with immunosuppressive activity. Tumor cells and stromal cells facilitate the activation and expansion of MDSCs in TME via intercellular communication, and expanded MDSCs suppress anti-tumor immune responses through direct and indirect mechanisms. Currently, exosomes, which are a kind of extracellular vesicles (EVs) that can convey functional components, are demonstrated to participate in the local and distal intercellular communication between cells. Numerous studies have supposed that tumor-derived exosomes (TEXs), whose assembly and release can be modulated by TME, are capable of modulating the cell biology of MDSCs, including facilitating their activation, promoting the expansion, and enhancing the immunosuppressive function. Therefore, in this review, we mainly focus on the role of TEXs in the cell-cell communication between tumor cells and MDSCs, and discuss their clinical applications.

Potential Therapeutic Effects of Exosomes Packed With a miR-21-Sponge Construct in a Rat Model of Glioblastoma

Glioblastoma multiforme (GBM) is a grade 4 and the most aggressive form of glioma, with a poor response to current treatments. The expression of microRNAs (miRNAs) is widely dysregulated in various cancers, including GBM. One of the overexpressed miRNAs in GBM is miR-21 which promotes proliferation, invasion and metastatic behaviors of tumor cells. With a size of 30-100 nm, the extracellular vesicles "exosomes" have emerged as a novel and powerful drug delivering systems. Recently, exosomal transfer of miRNAs or anti-miRNAs to tumor cells has introduced a new approach for therapeutic application of miRNAs to combat cancer. Here, we have tried to down-regulate miR-21 expression in glioma cell lines, U87-MG, and C6, by using engineered exosomes, packed with a miR-21-sponge construct. Our data revealed that the engineered exosomes have the potential to suppress miR-21 and consequently to upregulate miR-21 target genes, PDCD4 and RECK. Interestingly, in cells treated with miR-21-sponge exosomes we observed a decline in proliferation and also an elevation in apoptotic rates. Finally, in a rat model of glioblastoma, administrating exosomes loaded with a miR-21-sponge construct leads to a significant reduction in the volume of the tumors. In brief, our findings suggest a new therapeutic strategy to use engineered exosomes to deliver a miR-21-sponge construct to GBM cells, in order to block its malignant behavior.

The functions and clinical application potential of exosomes derived from adipose mesenchymal stem cells: a comprehensive review

Exosomes are extracellular membranous nanovesicles that mediate local and systemic intercellular communication by transporting proteins or nucleic acids (DNA and RNA) into target cells, thus altering the behaviors of recipient cells. Recent studies have revealed that these vesicles play a critical role in many biological functions, such as cell proliferation, immune regulation, nerve regeneration, and cancer. Adipose-derived stem cells (ADSCs) are now considered a multipotent and abundant tool in the field of cell therapy and regenerative medicine. ADSCs can produce and secrete many exosomes, which inherit multiple functions of cells. Therefore, in this review, we will introduce the characteristics of exosomes derived from ADSCs (ADSC-Exos), describe their functions in different biological processes, summarize the latest research achievements, describe their limitations in cell-free therapy, and provide further insights into their clinical application potential for the treatment of certain diseases.

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

Adipose tissue has long been considered to be involved in tumor progression. However, the adipocyte-secreted molecular determinants that regulate hepatocellular cancer progression have not been defined yet. In this study, the expression pattern of exosome miRNAs in hepatocellular carcinoma (HCC) patients with high body fat ratio (BFR) were identified by using low-density microarray. And the targets of exosome-miRNAs in HCC cells were predicted by bioinformatics methods and verified by in vitro as well as in vivo experiments. Here, we show that microRNA-23a/b (miR-23a/b) was significantly upregulated in both serum exosomes and tumor tissues of HCC patients with a high body fat ratio than low BFR. Subsequently, in vitro studies suggested that miR-23a/b was most likely to be derived from adipocytes and was transported into cancer cells via exosomes, thus promoting HCC cell growth and migration. Meanwhile, exosome miR-23a and miR-23b confer chemoresistance by targeting the von Hippel-Lindau/hypoxia-inducible factor axis. Our study provides evidence in that high BFR-related exosome miR23-a/b is a promising target for future treatment of HCC.

MiR-496 promotes migration and epithelial-mesenchymal transition by targeting RASSF6 in colorectal cancer

Aberrant loss of tumor-suppressor genes plays a crucial role in tumorigenesis and development of colorectal cancer (CRC). Extensive studies have reported tha hypermethylation of Ras association domain family member 6 (RASSF6) is common in various solid tumors. Another important mode of epigenetic regulation, microRNA (miRNA) regulation of RASSF6, is far from clear. The aim of the present work was to screen out novel miRNA regulating RASSF6, and to explore its underlying mechanism in CRC. With the use of bioinformatics, clinical sample data, and luciferase binding assay, we determined that microRNA-496 (miR-496) could be a novel oncomiR that directly binds to RASSF6. Next, a series of miR-496 mimics or inhibitor, or RASSF6 small interfering RNA (siRNA) introduced into CRC cells were applied to examine the effect of miR-496 on CRC cell viability, migration, and epithelial-mesenchymal transition (EMT). The results demonstrated that miR-496/RASSF6 could promote cell migration and EMT via Wnt signaling activation, but had no effect on cell viability. Our results confirmed that the miR-496/RASSF6 axis is involved in Wnt pathway-mediated tumor metastasis, highlighting its potential as a therapeutic target for CRC.

The functional roles of exosomal long non-coding RNAs in cancer

Exosomes are extracellular membranous vesicles that are secreted by various cell types. Exosomes have become indispensable facilitators in the exchange of information between cells. More importantly, exosomes perform a crucial role in a variety of diseases including cancers. Long non-coding RNAs (lncRNAs) are over 200 nucleotides long transcripts that exhibit no or limited protein-coding potentials. LncRNAs are an emerging group of regulatory RNAs and can be selectively packaged into exosomes. Exosomal lncRNAs play a central role in carcinogenesis and cancer progression by modulating tumor growth, metastasis, angiogenesis and chemoresistance. Moreover, exosomal lncRNAs function as messengers in cell-to-cell communication, and thus remodel the tumor microenvironment. Their function relevance in cancer biology hints at the possibility of employing exosomal lncRNAs as promising, non-invasive biomarkers for further cancer therapy. In this review, we provide an overview of current research on the functional roles of exosomal lncRNAs in cancer and discuss their potential clinical applications as diagnostic biomarkers and therapeutic targets for cancers.

Emerging Function and Clinical Values of Exosomal MicroRNAs in Cancer

Exosomes are a subset of membrane-bound extracellular vesicles with diameters ranging from 30 to 100 nm. Exosomes enclose a variety of molecules, such as lipids, proteins, and non-coding RNAs. In the past decades, microRNAs (miRNAs) have attracted great attention in cancer research, as they play an important role in the occurrence and development of cancer. Increasing evidence indicates that tumor cells communicate with not only other tumor cells but also cells present in the tumor microenvironment via secretion and transfer of exosomal miRNAs. More importantly, exosomal miRNAs are found to serve as signaling molecules to regulate tumor growth, angiogenesis, metastasis, sensitivity to chemotherapy, and immune evasion. Deregulated expression of exosomal miRNAs is an early event in carcinogenesis and may reflect the malignant characteristics of cancer. Owing to the wide existence and high stability of exosomal miRNAs in body fluids, they may represent a novel class of non-invasive biomarkers for cancer. In this review, we highlight the recent advances on the functional role of exosomal miRNAs in cancer pathogenesis. We also discuss the potential clinical utility of exosome-shuttled miRNAs as biomarkers for the diagnosis and treatment of cancer.

miR-148-3p Inhibits Growth of Glioblastoma Targeting DNA Methyltransferase-1 (DNMT1)

To date, miR-148-3p and DNMT1–recombinant human runt-related transcription factor 3 (RUNX3) axis have been linked to cell proliferation, migration, and invasion; however, their roles and relationships in human glioblastoma multiforme (GBM) are still not clear. Here we found that the expression of miR-148-3p in glioma tissues was decreased compared with adjacent nontumor tissues and correlated with WHO grade, tumor size, and prognosis as well as DNMT1 and RUNX3 expressions. Compared with NHA cells, the expression of miR-148-3p in U87 and U251 cells was also downregulated and accompanied with upregulation of DNMT1 and hypermethylation level of RUNX3 promoter region. miR-148-3p overexpression induced apoptosis and cell cycle arrest of U87 and U251 cells, and affected cell migration and invasion. miR-148-3p mimics effectively suppressed the expression of DNMT1 and methylation of RUNX3 promoter, finally upregulating RUNX3 expression. Mechanistically, the 3′-untranslated region (3′-UTR) of DNMT1 was a direct target of miR-148-3p. Overexpression of miR-148-3p or inhibition of DNMT1 induced the expression of E-cadherin and reduced the expressions of N-cadherin, vimentin, MMP-2, and MMP-9. In conclusion, miR-148-3p directly repressed the expression of DNMT1 and inhibited proliferation, migration, and invasion by regulating DNMT1–RUNX3 axis and the epithelial–mesenchymal transition in GBM. Our findings provide a new foundation for treatment of patients with GBM.

Extracellular miRNAs as activators of innate immune receptors

Since the discovery of the existence of microRNAs (miRNAs) in body fluids, the fascinating hypothesis that extracellular miRNAs may play a role in cell-to-cell signalling started to make its own way. In this review, we summarize the current knowledge that supports the role of miRNAs in the regulation of the immune response by an unconventional mechanism based on the activation of intracellular innate immune sensors of nucleic acids, namely the Toll-like receptors (TLRs). Such a mechanism of action has been now described to amplify and influence the pathogenesis of several inflammation-dependent pathological conditions, including cancer growth and metastasis, neurodegeneration, autoimmunity and cardiovascular diseases. The available data suggest that we have only begun to touch upon a complex system that is likely to involve many receptors and molecules. These findings may help to understand the pathogenesis of immune-mediated diseases and provide the basis for the identification of new potential therapeutic targets.

Exosome-transmitted miR-128-3p increase chemosensitivity of oxaliplatin-resistant colorectal cancer

Background

Oxaliplatin resistance is a major challenge for treatment of advanced colorectal cancer (CRC). Both acquisition of epithelial-mesenchymal transition (EMT) and suppressed drug accumulation in cancer cells contributes to development of oxaliplatin resistance. Aberrant expression of small noncoding RNA, miR-128-3p, has been shown to be a key regulator in tumorigenesis and cancer development. However, its roles in the progression of CRC and oxaliplatin-resistance are largely unknown.

Methods

Oxaliplatin-resistant CRC and normal intestinal FHC cells were transfected with a miR-128-3p expression lentivirus. After transfection, FHC-derived exosomes were isolated and co-cultured with CRC cells. miR-128-3p expression in resistant CRC cells, FHC cells, and exosomes was quantified by quantitative real-time PCR (RT-qPCR). The mRNA and protein levels of miR-128-3p target genes in resistant CRC cells were quantified by RT-qPCR and western blot, respectively. The effects of miR-128-3p on CRC cell viability, apoptosis, EMT, motility and drug efflux were evaluated by CCK8, flow cytometry, Transwell and wound healing assays, immunofluorescence, and atomic absorption spectrophotometry. Xenograft models were used to determine whether miR-128-3p loaded exosomes can re-sensitize CRC cells to oxaliplatin in vivo.

Results

In our established stable oxaliplatin-resistant CRC cell lines, in vitro and vivo studies revealed miR-128-3p suppressed EMT and increased intracellular oxaliplatin accumulation. Importantly, our results indicated that lower miR-128-3p expression was associated with poor oxaliplatin response in advanced human CRC patients. Moreover, data showed that miR-128-3p-transfected FHC cells effectively packaged miR-128-3p into secreted exosomes and mediated miR-128-3p delivery to oxaliplatin-resistant cells, improving oxaliplatin response in CRC cells both in vitro and in vivo. In addition, miR-128-3p overexpression up-regulated E-cadherin levels and inhibited oxaliplatin-induced EMT by suppressing Bmi1 expression in resistant cells. Meanwhile, it also decreased oxaliplatin efflux through suppressed expression of the drug transporter MRP5.

Conclusion

Our results demonstrate that miR-128-3p delivery via exosomes represents a novel strategy enhancing chemosensitivity in CRC through negative regulation of Bmi1 and MRP5. Moreover, miR-128-3p may be a promising diagnostic and prognostic marker for oxaliplatin-based chemotherapy.

Electronic supplementary material

The online version of this article (10.1186/s12943-019-0981-7) contains supplementary material, which is available to authorized users.

Progress of Exosomes in the Diagnosis and Treatment of Pancreatic Cancer

Pancreatic cancer (PC) is a digestive system tumor that is highly malignant, with an increasing incidence rate, poor prognosis, and a low 5-year survival rate. The overwhelming majority of patients with PC are in an advanced stage at the time of diagnosis and have lost the opportunity for radical surgery. The efficacy of radiotherapy and chemotherapy for PC is very poor. Therefore, it is of great significance to explore the mechanisms of PC development and new therapeutic targets. Exosomes are extracellular vesicles that mediate the exchange of substances and information between cells. In recent years, exosomes have been shown to play a key role in the development and progression of PC and might be useful for both its diagnosis and treatment. This article reviews the composition and function of exosomes and their roles in the development, diagnosis, and treatment of PC.

By regulating miR-182-5p/BCL10/CYCS, sufentanil reduces the apoptosis of umbilical cord mesenchymal stem cells caused by ropivacaine

Sufentanil is a type of opioid analgesic and is usually used to facilitate painless labor in combination with the local anesthetic ropivacaine. One aim of the current study was to investigate the effects of sufentanil and ropivacaine on umbilical cord mesenchymal stem cells (UCMSCs). A second aim of this study was to determine whether sufentanil attenuated the cytotoxicity of ropivacaine in vitro. UCMSCs were divided into 3 groups: one was treated with ropivacaine at a concentration of 50, 100, 200, or 400 μg/mL, another was treated with sufentanil at a concentration of 0.5, 5, 50, or 500 nmol/L, and a third was treated with a combination of ropivacaine at a concentration of 200 μg/mL and sufentanil at a concentration of 0.5, 5, 50, or 500 nmol/L. Results indicated that cell proliferation decreased in cells treated with ropivacaine while it increased in cells treated with sufentanil. In addition, sufentanil limited the inhibitory effect of ropivacaine on UCMSC growth in a dose- and time-dependent manner. Combined treatment with ropivacaine at a concentration of 200 μg/mL and sufentanil at a concentration of 500 nmol/L decreased the proportion of dead and apoptotic UCMSCs, and fewer cells were arrested in the S phase compared to cells treated with ropivacaine. Sufentanil inhibited the apoptosis induced by ropivacaine by increasing miR-182-5p, which regulated the expression of mRNA of the pro-apoptotic genes B-cell lymphoma/leukemia 10 (BCL10) and cytochrome c, somatic (CYCS). Sufentanil also increased the expression of mRNA of anti-apoptotic genes. In short, ropivacaine inhibits the cell viability and induces the apoptosis of UCMSCs in vitro while sufentanil attenuates this apoptosis by regulating miR182-5p/BCL10/CYCS.

A two-miRNA signature (miR-33a-5p and miR-128-3p) in whole blood as potential biomarker for early diagnosis of lung cancer

MicroRNAs (MiRNAs) have been found to be dysregulated in lung cancer tissues compared to their matched paracancerous tissues. However, the roles of miRNAs in peripheral blood as potential biomarkers for early diagnosis of lung cancer remain poorly understood. Here we found that miR-33a-5p and miR-128-3p were down-regulated in lung cancer tissues and cell lines. The expression levels of miR-33a-5p and miR-128-3p in lung cancer tissues were significantly correlated to TNM stages. MiR-128-3p in lung cancer tissues was also remarkably related to smoking and tumor size. The relative expression levels of miR-33a-5p and miR-128-3p were positively correlated in lung cancer tissues. Notably, miR-33a-5p and miR-128-3p in whole blood of lung cancer patients or early-stage lung cancer patients (TNM stage I-II) were lowly expressed as compared with that in healthy controls. The receiver operating characteristic curve (ROC) analyses revealed higher area under the ROC curve (AUC) values and higher sensitivity/specificity of miR-33a-5p and miR-128-3p alone and in combination were superior to that of traditional tumor markers (CYFR21-1, NSE and CA72-4). Importantly, both miR-33a-5p and miR-128-3p in whole blood were highly stable even under different harsh conditions. The results demonstrate that tumor suppressor miR-33a-5p/miR-128-3p in whole blood can serve as novel biomarkers for the early detection of lung cancer.