Effect of exosomal miRNA on cancer biology and clinical applications

MicroRNA-377-3p inhibits hepatocellular carcinoma growth and metastasis through negative regulation of CPT1C-mediated fatty acid oxidation

Background

Altered lipid metabolism is closely related to the occurrence and development of hepatocellular carcinoma (HCC). Carnitine palmitoyltransferase 1C (CPT1C) is a member of CPT1 family and plays a key role in cancer development and progression. However, how microRNAs (miRNAs) regulate CPT1C-mediated fatty acid transport and oxidation remains to be elucidated.

Methods

Oil Red O staining, mitochondrial, and lipid droplets immunofluorescence staining were used to detect the functions of miR-377-3p and CPT1C in fatty acid oxidation. Colocalization of palmitate and mitochondria was performed to investigate the function of miR-377-3p and CPT1C in fatty acid transport into mitochondria. Fatty acid oxidation (FAO) assay was used to detect the function of miR-377-3p and CPT1C in FAO. Cell proliferation, migration and invasion assays and animal experiments were used to evaluate the role of miR-377-3p/CPT1C axis in HCC progression in vitro and in vivo. Immunofluorescence staining was used to identify the clinical significance of miR-377-3p and CPT1C in HCC patients.

Results

MiR-377-3p inhibits CPT1C expression by targeting its 3’-untranslated region. Through repression of CPT1C, miR-377-3p suppresses fatty acid oxidation by preventing fatty acid from entering into mitochondria and decreasing ATP production in HCC cells. Inhibiting fatty acid oxidation abolishes the ability of miR-377-3p/CPT1C axis to regulate HCC proliferation, migration, invasion and metastasis in vitro and in vivo. In HCC patients, CPT1C is significantly upregulated, and miR-377-3p expression and lipid droplets are negatively correlated with CPT1C expression. High expression of miR-377-3p and CPT1C predict better and worse clinical outcomes, respectively.

Conclusions

We uncover the key function and the relevant mechanisms of the miR-377-3p/CPT1C axis in HCC, which might provide a potential target for the treatment of HCC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40170-021-00276-3.

Exosomes from M1‐polarized macrophages promote apoptosis in lung adenocarcinoma via the miR‐181a‐5p/ETS1/STK16 axis

Serine/threonine kinase 16 (STK16) is crucial in on regulating tumor cell proliferation, apoptosis, and prognosis. Activated M1 macrophages regulate lung adenocarcinoma (LUAD) growth by releasing exosomes. This study aims to investigate the role of STK16 and then focus on the possible mechanisms through which exosomes derived from M1 macrophages play their roles in LUAD cells by targeting STK16. Clinical LUAD samples were used to evaluate the expression of STK16 and its association with prognosis. Exosomes were isolated from M0 and M1 macrophages by ultracentrifugation and were then identified by electron microscopy and western blotting. In vitro gain‐ and loss‐of‐function experiments with LUAD cells were performed to elucidate the functions of miR‐181a‐5p, ETS1, and STK16, and mouse xenograft models were used to verify the function of STK16 in vivo. Western blotting, quantitative real‐time PCR, CCK‐8 assay, cell apoptosis, immunohistochemistry staining, luciferase assay, ChIP assay, and bioinformatics analysis were performed to reveal the underlying mechanisms. High expression of STK16 was observed in LUAD tissues and cells, and higher expression of STK16 was associated with worse prognosis. Silencing STK16 expression inhibited cell proliferation and promoted apoptosis via the AKT1 pathway. Exosomes from M1 macrophages inhibited viability and promoted apoptosis by inhibiting STK16. Moreover, miR‐181a‐5p is the functional molecule in M1 macrophage‐derived exosomes and plays a vital role in inhibiting cell proliferation and promoting apoptosis by targeting ETS1 and STK16. Hence, exosomes derived from M1 macrophages were capable of inhibiting viability and promoting apoptosis in LUAD via the miR‐181a‐5p/ETS1/STK16 axis.

Exosome-Mediated miR-4792 Transfer Promotes Bladder Cancer Cell Proliferation via Enhanced FOXC1/c-Myc Signaling and Warburg Effect

Bladder cancer is the second-most common malignancy in the urogenital system and the most common in men. However, our understanding of the driving mechanisms of bladder cancer remains incomplete. The forkhead box (FOX) family of transcription factors is implicated in urogenital development and bladder malignancies. Many exosomal microRNAs have been identified as regulators and mediators of the expression of FOX, including the expression of FOXC1. miR-4792 has been known as a tumor miRNA suppressor. However, the function of miR-4792/FOXC1 signaling in bladder cancer development remains unknown. Here, we studied the role of miR-4792/FOXC1 signaling in bladder cancer by using multiple bladder cancer cell lines and bladder cancer mouse models through in vitro and in vivo approaches. We showed that FOXC1 is highly expressed in multiple bladder cancer cell lines and bladder tumor tissues. The knockdown of FOXC1 expression in bladder cancer cell lines decreases c-Myc expression levels, retards cell growth, and reduces aerobic glycolysis (also known as the Warburg effect) and lactic acid content. By contrast, the overexpression of FOXC1 elicits the opposite effects. FOXC1-downregulated bladder cancer cells form significantly smaller tumors in vivo. The inhibition of c-Myc reverses the effects of FOXC1 overexpression and leads to reduced cell proliferation, aerobic glycolysis, and lactic acid content. miR-4792 expression is downregulated in bladder tumor tissues. miR-4792 exposure to bladder cancer cells reduces the expression levels of FOXC1 and c-Myc, slows down cell growth, and decreases aerobic glycolysis and lactic acid content. However, the enhanced miR-4792 expression elicits opposite effects. These findings provided the first evidence that the exosome-mediated delivery of miR-4792 could play an important role in bladder cancer development through the downregulation of FOXC1 and c-Myc, which further inhibited aerobic glycolysis and lactic acid content.

A portable system for isothermal amplification and detection of exosomal microRNAs

Exosomal microRNAs (miRNAs) play a key role in cell-cell communication to regulate gene expression in target cells and have great potential as biomarkers for disease diagnosis. This paper reports an on-chip exosomal miRNA amplification and detection system for rapid analysis of exosomal miRNAs. The compact system consists of two connected flow cells for processing exosomes and detecting miRNAs, respectively. The miRNAs extracted from exosomes were quantitatively measured using the on-chip exponential amplification reaction (EXPAR) assay. The sensor chip was designed to store multiple oligonucleotide templates for the EXPAR, mix sample and reagent, and simultaneously analyze multiple exosomal miRNAs of interest. To facilitate the miRNA analysis, a portable detection instrument was built on an IoT platform using a low-cost microcontroller to execute the EXPAR assay, collect fluorescent images, and analyze amplification curves. Here, we studied the miRNA profiles carried by exosomes derived from three different phenotypes of tissue macrophages. The affordable instrument, rapid assay, multiplexed analysis, as well as disposable sensor chip, would boost the development of point-of-care liquid biopsy tests using exosomal miRNAs.

Cancer exosomes and natural killer cells dysfunction: biological roles, clinical significance and implications for immunotherapy

Tumor-derived exosomes (TDEs) play pivotal roles in several aspects of cancer biology. It is now evident that TDEs also favor tumor growth by negatively affecting anti-tumor immunity. As important sentinels of immune surveillance system, natural killer (NK) cells can recognize malignant cells very early and counteract the tumor development and metastasis without a need for additional activation. Based on this rationale, adoptive transfer of ex vivo expanded NK cells/NK cell lines, such as NK-92 cells, has attracted great attention and is widely studied as a promising immunotherapy for cancer treatment. However, by exploiting various strategies, including secretion of exosomes, cancer cells are able to subvert NK cell responses. This paper reviews the roles of TDEs in cancer-induced NK cells impairments with mechanistic insights. The clinical significance and potential approaches to nullify the effects of TDEs on NK cells in cancer immunotherapy are also discussed.

Targeted Delivery of Exosomes Armed with Anti-Cancer Therapeutics

Among extracellular vesicles, exosomes have gained great attention for their role as therapeutic vehicles for delivering various active pharmaceutical ingredients (APIs). Exosomes “armed” with anti-cancer therapeutics possess great potential for an efficient intracellular delivery of anti-cancer APIs and enhanced targetability to tumor cells. Various technologies are being developed to efficiently incorporate anti-cancer APIs such as genetic materials (miRNA, siRNA, mRNA), chemotherapeutics, and proteins into exosomes and to induce targeted delivery to tumor burden by exosomal surface modification. Exosomes can incorporate the desired therapeutic molecules via direct exogenous methods (e.g., electroporation and sonication) or indirect methods by modifying cells to produce “armed” exosomes. The targeted delivery of “armed” exosomes to tumor burden could be accomplished either by “passive” targeting using the natural tropism of exosomes or by “active” targeting via the surface engineering of exosomal membranes. Although anti-cancer exosome therapeutics demonstrated promising results in preclinical studies, success in clinical trials requires thorough validation in terms of chemistry, manufacturing, and control techniques. While exosomes possess multiple advantages over synthetic nanoparticles, challenges remain in increasing the loading efficiency of anti-cancer agents into exosomes, as well as establishing quantitative and qualitative analytical methods for monitoring the delivery of in vivo administered exosomes and exosome-incorporated anti-cancer agents to the tumor parenchyma.

N6‑methyladenosine upregulates miR‑181d‑5p in exosomes derived from cancer‑associated fibroblasts to inhibit 5‑FU sensitivity by targeting NCALD in colorectal cancer

Resistance to 5‑Fluorouracil (5‑FU) is a frequent occurrence in patients with colorectal cancer (CRC). MicroRNAs (miRNAs) from cancer‑associated fibroblasts (CAFs)‑secreted exosomes have been associated with 5‑FU sensitivity. The potential molecular mechanism of CAFs‑exosomal miRNAs in CRC remains unclear. The aim of the present study was to elucidate the role of exosomal miRNAs in 5‑FU sensitivity in CRC. Exosomes derived from CAFs were extracted. Exosomal miR‑181d‑5p was identified as a miRNA associated with 5‑FU sensitivity. The putative function of exosomal miR‑181d‑5p was evaluated by ethynyl‑2‑deoxyuridine staining, flow cytometry, RNA immunoprecipitation, luciferase reporter assay, tumor xenograft formation, reverse transcription‑quantitative PCR and western blot analysis. Modification of miR‑181d‑5p by the RNA N6‑methyladenosine (m⁶A) methyltransferase like (METTL)3 was examined by m6A methylation analysis. The results indicated that m⁶A modification and METTL3 expression were upregulated in CRC patients. METTL3‑dependent m⁶A methylation promoted the miR‑181b‑5p process by DiGeorge Syndrome Critical Region 8 (DGCR8) in CAFs. CAFs‑derived exosomes inhibited 5‑FU sensitivity in CRC cells through the METTL3/miR‑181d‑5p axis. A mechanistic study revealed that miR‑181d‑5p directly targeted neurocalcin δ (NCALD) to inhibit the 5‑FU sensitivity of CRC cells. Patients with higher NCALD levels exhibited a higher survival rate. Taken together, METTL3‑dependent m⁶A methylation was upregulated in CRC to promote the processing of miR‑181d‑5p by DGCR8. This led to increased miR‑181d‑5p expression, which inhibited the 5‑FU sensitivity of CRC cells by targeting NCALD. The results of the present study provided novel insight into exosomal microRNAs in 5‑FU sensitivity in CRC cells. Furthermore, exosomal miR‑181d‑5p may represent a potential prognostic marker for CRC.

Nanoparticulate strategies for the delivery of miRNA mimics and inhibitors in anticancer therapy and its potential utility in oral submucous fibrosis

MicroRNAs (miRNAs) are naturally occurring noncoding RNAs with multiple functionalities. They are dysregulated in several conditions and can serve as disease biomarkers, therapeutic targets and therapeutic agents. Translation of miRNA therapeutics to the clinic poses several challenges related to the safe and effective delivery of these agents to the site of action. Nanoparticulate carriers hold promise in this area by enhancing targeting efficiency and reducing off-target effects. This paper reviews recent advances in the delivery strategies of miRNAs in anticancer therapy, with a focus on lipid-based, polymeric, inorganic platforms, cell membrane-derived vesicles and bacterial minicells. Additionally, this review explores the potentiality of miRNAs in the treatment of oral submucous fibrosis, a potentially premalignant condition of the oral cavity with no definitive treatment to date.

Bone mesenchymal stem cell-derived exosomal microRNA-7-5p inhibits progression of acute myeloid leukemia by targeting OSBPL11

BACKGROUND

Acute myeloid leukemia (AML) is a malignant clonal disease of hematopoietic stem- and progenitor-cell origin. AML features massive proliferation of abnormal blasts and leukemia cells in the bone marrow and the inhibition of normal hematopoiesis at onset. Exosomes containing proteins or nucleic acids are secreted by cells; they participate in intercellular communication and serve as key modulators of hematopoiesis. The purpose of this study was to investigate the effects of exosomes derived from bone marrow mesenchymal stem cells (BMSCs) on the regulation of AML and the underlying mechanisms mediated by microRNA (miRNA).

METHODS

Dysregulated miR-7-5p in AML patients was identified using qRT-PCR and its clinical significance was explored. Bioinformatic analysis revealed the target gene OSBPL11 that could be regulated by miR-7-5p. The findings were validated using a dual-luciferase reporter assay and western blotting. The functional genes of the PI3K/AKT/mTOR signaling pathway were identified, and the functional significance of miR-7-5p in AML cells was determined using a functional recovery assay. AML cells were co-cultured with exosomes originating from BMSCs overexpressing miR-7-5p to determine cell-cell regulation by Exo-miR-7-5p, as well as in vitro and in vivo functional validation via gain- and loss-of-function methods.

RESULTS

Expression of miR-7-5p was decreased in AML patients and cells. Overexpression of miR-7-5p curbed cellular proliferation and promoted apoptosis. Overexpression of OSBPL11 reversed the tumorigenic properties of miR-7-5p in AML cells in vitro. Exo-miR-7-5p derived from BMSCs induced formation of AML cells prone to apoptosis and a low survival rate, with OSBPL11 expression inhibited through the PI3K/AKT/mTOR signaling pathway. Exo-miR-7-5p derived from BMSCs exhibited tumor homing effects in vitro and in vivo, and inhibited AML development.

CONCLUSIONS

Exo-miR-7-5p derived from BMSCs negatively regulates OSBPL11 by suppressing the phosphorylation of the PI3K/AKT/mTOR signaling pathway, thereby inhibiting AML proliferation and promoting apoptosis. The data will inform the development of AML therapies based on BMSC-derived exosomes.

Circ_0000647 promotes cell injury by modulating miR-126-5p/TRAF3 axis in oxygen-glucose deprivation and reperfusion-induced SK-N-SH cell model

BACKGROUND

Emerging evidence has shown that circular RNAs (circRNAs) are involved in the pathogenesis of ischemic stroke (IS). Nonetheless, the function of circ_0000647 was not reported.

METHODS

Oxygen-glucose deprivation and reperfusion (OGD/R)-treated SK-N-SH cells were used to mimic cerebral ischemia/reperfusion (I/R) conditions. Quantitative real-time polymerase chain reaction (qRT-PCR) and western blot were used to measure the levels of circ_0000647, microRNA-126-5p (miR-126-5p) and TNF receptor associated factor 3 (TRAF3). Cell Counting Kit-8 (CCK-8) assay, 5'-ethynyl-2'-deoxyuridine (EDU) assay and flow cytometry analysis were employed to assess cell proliferation and apoptosis. Enzyme-linked immunosorbent assay (ELISA) was conducted for the concentrations of IL-6 and TNF-α. Oxidative stress was assessed by determining malondialdehyde (MDA) level and superoxide dismutase (SOD) activity. Dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay were adopted to estimate the relationships of circ_0000647, miR-126-5p and TRAF3. The morphology and size of exosomes were observed via transmission electron microscopy (TEM) and nanoparticle tracking analysis (NTA) analysis.

RESULTS

Circ_0000647 was elevated in OGD/R-treated SK-N-SH cells. OGD/R treatment suppressed the proliferation and promoted the apoptosis, inflammation and oxidative stress in SK-N-SH cells, while circ_0000647 knockdown reversed the effects. Circ_0000647 could sponge miR-126-5p, which directly targeted TRAF3. MiR-126-5p overexpression alleviated OGD/R-induced SK-N-SH cell damage and miR-126-5p inhibition reversed the effect of circ_0000647 knockdown on OGD/R-induced SK-N-SH cell damage. Moreover, TRAF3 elevation abated miR-126-5p-mediated effect on SK-N-SH cell injury. In addition, exosomal circ_0000647 level was increased in OGD/R-stimulated SK-N-SH cells.

CONCLUSION

Circ_0000647 interference relieved OGD/R-induced SK-N-SH cell damage by altering miR-126-5p/TRAF3 axis.

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

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

LncRNA HCG18 promotes osteosarcoma growth by enhanced aerobic glycolysis via the miR-365a-3p/PGK1 axis

Background

Osteosarcoma (OS) is a common primary bone malignancy. Long noncoding RNA HCG18 is known to play an important role in a variety of cancers. However, its role in OS and relevant molecular mechanisms are unclear.

Methods

Real-time quantitative PCR was performed to determine the expression of target genes. Function experiments showed the effects of HCG18 and miR-365a-3p on OS cell growth.

Results

HCG18 expression was increased in OS cell lines. Moreover, in vitro and in vivo experiments demonstrated that HCG18 knockdown inhibited OS cell proliferation. Mechanistically, HCG18 was defined as a competing endogenous RNA by sponging miR-365a-3p, thus elevating phosphoglycerate kinase 1 (PGK1) expression by directly targeting its 3ʹUTR to increase aerobic glycolysis.

Conclusion

HCG18 promoted OS cell proliferation via enhancing aerobic glycolysis by regulating the miR-365a-3p/PGK1 axis. Therefore, HCG18 may be a potential target for OS treatment.

Supplementary Information

The online version contains supplementary material available at 10.1186/s11658-021-00304-6.

The role of Exosomal miRNAs in cancer

Exosomal miRNAs have attracted much attention due to their critical role in regulating genes and the altered expression of miRNAs in virtually all cancers affecting humans (Sun et al. in Mol Cancer 17(1):14, 2018). Exosomal miRNAs modulate processes that interfere with cancer immunity and microenvironment, and are significantly involved in tumor growth, invasion, metastasis, angiogenesis and drug resistance. Fully investigating the detailed mechanism of miRNAs in the occurrence and development of various cancers could help not only in the treatment of cancers but also in the prevention of malignant diseases. The current review highlighted recently published advances regarding cancer-derived exosomes, e.g., sorting and delivery mechanisms for RNAs. Exosomal miRNAs that modulate cancer cell-to-cell communication, impacting tumor growth, angiogenesis, metastasis and multiple biological features, were discussed. Finally, the potential role of exosomal miRNAs as diagnostic and prognostic molecular markers was summarized, as well as their usefulness in detecting cancer resistance to therapeutic agents.

Small extracellular vesicles: from mediating cancer cell metastasis to therapeutic value in pancreatic cancer

Pancreatic cancer is a highly malignant tumor and, is extremely difficult to diagnose and treat. Metastasis is one of the critical steps in the development of cancer and uses cell to cell communication to mediate changes in the microenvironment. Small extracellular vesicles (sEVs)-carry proteins, nucleic acids and other bioactive substances, and are important medium for communication between cells. There are two primary steps in sVEs-mediated metastasis: communication between pancreatic cancer cells and their surrounding microenvironment; and the communication between primary tumor cells and distant organ cells in distant organs that promotes angiogenesis, reshaping extracellular matrix, forming immunosuppressive environment and other ways to form appropriate pre-metastasis niche. Here, we explore the mechanism of localization and metastasis of pancreatic cancer and use sEVs as early biomarkers for the detection and treatment of pancreatic cancer. Video Abstract.

CAF promotes chemoresistance through NRP2 in gastric cancer

BACKGROUND

Fibroblasts are the predominant cell type in the stroma of tumor, and cancer-associated fibroblasts (CAFs) promote cancer chemoresistance by secreting various bioactive molecules. However, the differential expression between CAFs and normal fibroblasts (NFs) and how can CAFs uniquely impact cancer cells are still unexplored.

METHODS

Primary CAFs and NFs were cultured from gastric cancer specimens, and their variant expression was analyzed by RNA-sequencing. Chemoresistance was evaluated by measuring cell viability, apoptosis, and 3D-coculture techniques.

RESULTS

CAFs were isolated from gastric cancers and defined by specific cell-surface markers. CAFs decreased the sensitivity of gastric cancer cells to 5-FU. RNA-sequencing showed that CAFs expressed a higher level of NRP2 than NFs. And the high expression of NRP2 was correlated with worse oncological outcomes in gastric cancer patients. Further study showed that the knockdown of NRP2 eradicated the resistance to 5-FU. And the secretion of stromal cell-derived factor-1 (SDF-1) was reduced following NRP2 knockdown. Furthermore, we found that the increased sensitivity to 5-FU was induced by DNA damage. And this process was mediated by predominant effectors of the Hippo pathway, YAP/TAZ.

CONCLUSIONS

The present study indicated that CAFs within gastric cancers promote chemoresistance through the expression of NRP2. The secretion of SDF-1 that mediated by VEGF/NRP2 signaling in CAFs and the activation of Hippo pathway in cancer cells in large part participated in this project.

Efficient exosome subpopulation isolation and proteomic profiling using a Sub-ExoProfile chip towards cancer diagnosis and treatment

Deconstruction of the heterogeneity of surface marker-dependent exosome subpopulations by the Sub-ExoProfile chip.

Comparing miR-16 and miR-1228 as an optimal endogenous control for quantification of circulating microRNAs in colorectal cancer patients

Objectives:

Circulating microRNAs (miRNAs) have been discovered to play a novel role in intercellular communication and cancer biology. They are emerging candidates for noninvasive molecular biomarkers of cancer and other diseases. However, current translational researches have been limited by the lack of consensus on the optimal endogenous control of circulating miRNAs quantitation. In this study, we compared two promising miRNAs, miR-1228 and miR-16, as an endogenous control. The effects of normalizers on the relative quantification of circulating miR-31 in plasma samples of colorectal cancer (CRC) were also assessed.

Materials and Methods:

The cel-miR-39 was a spiked-in RNA used as an external control and added to plasma samples before RNA extraction. Quantitative real-time polymerase chain reaction technology was used to analyze the expression levels of circulating miRNAs in plasma samples of 4 healthy controls and 14 CRC patients. The expression stability of the candidate controls was compared by Ct analysis and NormFinder algorithms.

Results:

There was no significant difference in expression level of miR-16 and miR-1228 between healthy control group and before or after therapy of CRC patient groups. The expression of miR-1228 has smaller the range Ct values (28.25-25.64)compared with those of miR-16 (24.91-20.34). The stability value of miR-1228 (0.102) is lower than that of miR-16 (0.350). The expression of miR-1228 endogenous reference candidate has lower stability value and smaller the range Ct values compared with those in miR-16. According to the range Ct values and stability value, miR-1228 is better than miR-16 as endogenous control in CRC patients. There are significant differences in circulating miR-31 expression between healthy control and CRC patients when miR-1228 was used to standardize miR-31 expression.

Conclusions:

miR-1228 is recommended as a better endogenous control in quantification of circulating miRNAs in CRC patients.

Hallmarks of exosomes

Exosomes are a new horizon in modern therapy, presenting exciting new opportunities for advanced drug delivery and targeted release. Exosomes are small extracellular vesicles with a size range of 30-100 nm, secreted by all cell types in the human body and carrying a unique collection of DNA fragments, RNA species, lipids, protein biomarkers, transcription factors and metabolites. miRNAs are one of the most common RNA species in exosomes, and they play a role in a variety of biological processes including exocytosis, hematopoiesis and angiogenesis, as well as cellular communication via exosomes. Exosomes can act as cargo to transport this information from donor cells to near and long-distance target cells, participating in the reprogramming of recipient cells.

Plasma Exosomal Mir-423-5p Is Involved in the Occurrence and Development of Bicuspid Aortopathy via TGF-β/SMAD2 Pathway

Objectives: Patients with bicuspid aortic valve (BAV) are at increased risk for ascending aortic dilation (AAD). Our study was aimed at systemically analyzing the expression profile and mechanism of circulating plasma exosomal microRNAs (miRNAs) related to BAV and AAD.

Methods: We isolated plasma exosomes from BAV patients (n=19), BAV patients with AAD (BAVAD, n=26), and healthy tricuspid aortic valve individuals with low cardiovascular risk (TAVnon, n=16). We applied a small RNA sequencing approach to identify the specific plasma exosomal miRNAs associated with BAV (n=8) and BAVAD (n=10) patients compared with healthy TAVnon (n=6) individuals. The candidate differentially expressed (DE) miRNAs were selected and validated by RT-qPCR in the remaining samples. GO and KEGG pathway enrichment analyses were performed to illustrate the functions of target genes. Western blot analysis and luciferase reporter assay were conducted in human aortic vascular smooth muscle cells (VSMCs) to verify the results of target gene prediction in vitro.

Results: The expression levels of three up-regulated (miR-151a-3p, miR-423-5p, and miR-361-3p) and two down-regulated (miR-16-5p and miR-15a-5p) exosomal miRNAs were significantly altered in BAV disease. Additionally, miR-423-5p could be functionally involved in the occurrence and development of BAV and its complication BAVAD by regulating TGF-β signaling. miR-423-5p could target to SMAD2 and decreased the protein levels of SMAD2 and P-SMAD2.

Conclusion: Plasma exosomal miR-423-5p regulated TGF-β signaling by targeting SMAD2, thus exerting functions in the occurrence and development of BAV disease and its complication bicuspid aortopathy.

Hepatitis B core antigen modulates exosomal miR-135a to target vesicle-associated membrane protein 2 promoting chemoresistance in hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors. The association of hepatitis B virus (HBV) infection with HCC is hitherto documented. Exosomal miRNAs contribute to cancer progression and chemoresistance. HBV X protein has been known to modulate miRNAs that facilitate cell proliferation and the process of hepatocarcinogenesis. However, there has been no report on hepatitis B core antigen (HBc) regulating exosomal miRNAs to induce drug resistance of HCC cells.

AIM

To elucidate the mechanism by which HBc promotes Doxorubicin hydrochloride (Dox) resistance in HCC.

METHODS

Exosomes were isolated by ultracentrifugation. The morphology and size of exosomes were evaluated by Dynamic Light Scattering (DLS) and transmission electron microscopy (TEM). The miRNAs differentially expressed in HCC were identified using The Cancer Genome Atlas (TCGA) database. The level of miR-135a-5p in patient tissue samples was detected by quantitative polymerase chain reaction. TargetScan and luciferase assay were used to predict and prove the target gene of miR-135a-5p. Finally, we identified the effects of miR-135a-5p on anti-apoptosis and the proliferation of HCC in the presence or absence of Dox using flow cytometry, Cell counting kit 8 (CCK-8) assay and western blot.

RESULTS

We found that HBc increased the expression of exosomal miR-135a-5p. Integrated analysis of bioinformatics and patient samples found that miR-135a-5p was increased in HCC tissues in comparison with paracancerous tissues. Bioinformatic analysis and in vitro validation identified vesicle-associated membrane protein 2 (VAMP2) as a novel target gene of miR-135a-5p. Functional assays showed that exosomal miR-135a-5p induced apoptosis protection, cell proliferation, and chemotherapy resistance in HCC. In addition, the rescue experiment demonstrated that VAMP2 reversed apoptosis protection, cell growth, and drug resistance by miR-135a-5p. Finally, HBc promoted HCC anti-apoptosis, proliferation, and drug resistance and prevented Dox-induced apoptosis via the miR-135a-5p/VAMP2 axis.

CONCLUSION

These data suggested that HBc upregulated the expression of exosomal miR-135a-5p and promoted anti-apoptosis, cell proliferation, and chemical resistance through miR-135a-5p/VAMP2. Thus, our work indicated an essential role of the miR-135a-5p/VAMP2 regulatory axis in chemotherapy resistance of HCC and a potential molecular therapeutic target for HCC.

miR-30a-5p promotes glomerular podocyte apoptosis via DNMT1-mediated hypermethylation under hyperhomocysteinemia

Abnormal elevation of homocysteine (Hcy) level is closely related to the development and progression of chronic kidney disease (CKD), with the molecular mechanisms that are not fully elucidated. Given the demonstration that miR-30a-5p is specifically expressed in glomerular podocytes, in the present study we aimed to investigate the role and potential underlying mechanism of miR-30a-5p in glomerular podocyte apoptosis induced by Hcy. We found that elevated Hcy downregulates miR-30a-5p expression in the mice and Hcy-treated podocytes, and miR-30a-5p directly targets the 3'-untranslated region (3'-UTR) of the forkhead box A1 (FOXA1) and overexpression of miR-30a-5p inhibits FOXA1 expression. By nMS-PCR and MassARRAY quantitative methylation analysis, we showed the increased DNA methylation level of miR-30a-5p promoter both and . Meanwhile, dual-luciferase reporter assay showed that the region between --1400 and --921 bp of miR-30a-5p promoter is a possible regulatory element for its transcription. Mechanistic studies indicated that DNA methyltransferase enzyme 1 (DNMT1) is the key regulator of miR-30a-5p, which in turn enhances miR-30a-5p promoter methylation level and thereby inhibits its expression. Taken together, our results revealed that epigenetic modification of miR-30a-5p is involved in glomerular podocyte injury induced by Hcy, providing a diagnostic marker candidate and novel therapeutic target in CKD induced by Hcy.

Autophagy and ncRNAs: Dangerous Liaisons in the Crosstalk between the Tumor and Its Microenvironment

Simple Summary

Tumor cells communicate with the stromal cells within the tumor microenvironment (TME) to create a conducive environment for tumor growth. One major avenue for mediating crosstalk between various cell types in the TME involves exchanges of molecular payloads in the form of extracellular vesicles/exosomes. Autophagy is a fundamental mechanism to maintain intracellular homeostasis but recent reports suggest that secretory autophagy plays an important role in promoting secretion of exosomes that are packaged with non-coding RNAs (ncRNAs) and other biomolecules from the donor cell. Uptake of exosomal autophagy-modulating ncRNAs by recipient cells may further perpetuate tumor progression.

Abstract

Autophagy is a fundamental cellular homeostasis mechanism known to play multifaceted roles in the natural history of cancers over time. It has recently been shown that autophagy also mediates the crosstalk between the tumor and its microenvironment by promoting the export of molecular payloads such as non-coding RNA (ncRNAs) via LC3-dependent Extracellular Vesicle loading and secretion (LDELS). In turn, the dynamic exchange of exosomal ncRNAs regulate autophagic responses in the recipient cells within the tumor microenvironment (TME), for both tumor and stromal cells. Autophagy-dependent phenotypic changes in the recipient cells further enhance tumor growth and metastasis, through diverse biological processes, including nutrient supplementation, immune evasion, angiogenesis, and therapeutic resistance. In this review, we discuss how the feedforward autophagy-ncRNA axis orchestrates vital communications between various cell types within the TME ecosystem to promote cancer progression.

Plasma-Derived Extracellular Vesicles Circular RNAs Serve as Biomarkers for Breast Cancer Diagnosis

Breast cancer is the second cause of cancer-associated death among women and seriously endangers women's health. Therefore, early identification of breast cancer would be beneficial to women's health. At present, circular RNA (circRNA) not only exists in the extracellular vesicles (EVs) in plasma, but also presents distinct patterns under different physiological and pathological conditions. Therefore, we assume that circRNA could be used for early diagnosis of breast cancer. Here, we developed classifiers for breast cancer diagnosis that relied on 259 samples, including 144 breast cancer patients and 115 controls. In the discovery stage, we compared the genome-wide long RNA profiles of EVs in patients with breast cancer (n=14) and benign breast (n=6). To further verify its potential in early diagnosis of breast cancer, we prospectively collected plasma samples from 259 individuals before treatment, including 144 breast cancer patients and 115 controls. Finally, we developed and verified the predictive classifies based on their circRNA expression profiles of plasma EVs by using multiple machine learning models. By comparing their circRNA profiles, we found 439 circRNAs with significantly different levels between cancer patients and controls. Considering the cost and practicability of the test, we selected 20 candidate circRNAs with elevated levels and detected their levels by quantitative real-time polymerase chain reaction. In the training cohort, we found that BC_ExoC, a nine-circRNA combined classifier with SVM model, achieved the largest AUC of 0.83 [95% CI 0.77-0.88]. In the validation cohort, the predictive efficacy of the classifier achieved 0.80 [0.71-0.89]. Our work reveals the application prospect of circRNAs in plasma EVs as non-invasive liquid biopsies in the diagnosis and management of breast cancer.

Tumor-derived exosomes: Key players in non-small cell lung cancer metastasis and their implication for targeted therapy

Exosomes represent extracellular vesicles of endocytic origin ranging from 30 to 100 nm that are released by most of eukaryotic cells and can be found in body fluids. These vesicles in carrying DNA, RNA, microRNA (miRNA), Long noncoding RNA, proteins, and lipids serve as intercellular communicators. Due to their role in crosstalk between tumor cells and mesenchymal stroma cells, they are vital for tumor growth, progression, and anticancer drug resistance. Lung cancer is a global leading cause of cancer-related deaths with 5-year survival rates of about 7% in patients with distant metastasis. Although the implementation of targeted therapy has improved the clinical outcome of nonsmall cell lung cancer, drug resistance remains a major obstacle. Lung tumor-derived exosomes (TDEs) conveying molecular information from tumor cells to their neighbor cells or cells at distant sites of the body activate the tumor microenvironment (TME) and facilitate tumor metastasis. Exosomal miRNAs are also considered as noninvasive biomarkers for early diagnosis of lung cancer. This review summarizes the influence of lung TDEs on the TME and metastasis. Their involvement in targeted therapy resistance and potential clinical applications are discussed. Additionally, challenges encountered in the development of exosome-based therapeutic strategies are addressed.

Challenges for the Development of Extracellular Vesicle-Based Nucleic Acid Medicines

Nucleic acid drugs, such as siRNAs, antisense oligonucleotides, and miRNAs, exert their therapeutic effects by causing genetic changes in cells. However, there are various limitations in their delivery to target organs and cells, making their application to cancer treatment difficult. Extracellular vesicles (EVs) are lipid bilayer particles that are released from most cells, are stable in the blood, and have low immunogenicity. Methods using EVs to deliver nucleic acid drugs to target organs are rapidly being developed that take advantage of these properties. There are two main methods for loading nucleic acid drugs into EVs. One is to genetically engineer the parent cell and load the target gene into the EV, and the other is to isolate EVs and then load them with the nucleic acid drug. Target organ delivery methods include passive targeting using the enhanced permeation and retention effect of EVs and active targeting in which EVs are modified with antibodies, peptides, or aptamers to enhance their accumulation in tumors. In this review, we summarize the advantages of EVs as a drug delivery system for nucleic acid drugs, the methods of loading nucleic acid drugs into EVs, and the targeting of EVs to target organs.

miRNA-214-5p inhibits prostate cancer cell proliferation by targeting SOX4

Background

Prostate cancer is the most common malignant tumor in men. Due to the lack of theoretical research on its pathogenic mechanism, the current cure rate is still low. miRNAs play an important role in the pathogenesis of various cancers. miRNA-214-5p plays an important role in the development of a variety of cancers. This study aims to explore the expression level of miR-214-5p in prostate cancer and make a preliminary study of its molecular mechanism in the development of prostate cancer to provide effective new strategies for the treatment of prostate cancer.

Methods

The target genes of miRNA-214-5p were predicted with bioinformatics technology, and the target relationship between miRNA-214-5p and its target genes was verified with dual luciferase reporter assay. RT-qPCR and Western blot were used to detect the expression levels of miRNA-214-5p and target genes in 50 clinical samples and two common prostate continuous cell lines, respectively. The targeting relationship between miRNA-214-5p and its target genes was verified with clinical data. miRNA-214-5p and miRNA-214-5p inhibitor was over-expressed in DU-145 cell lines to verify the effect of miRNA-214-5p on prostate cancer cell proliferation and SOX4 gene expression. And the mechanism of miRNA-214-5p inhibiting the proliferation of prostate cancer cells were analyzed by detecting the expression difference of downstream factors of SOX4 pathway. Bioinformatics analysis showed that miRNA-214-5p combined with SOX4 3′UTR region, and dual luciferase reporter assay further verified the reliability of the predicted results. The low expression of miRNA-214-5p was observed in prostate cancer tissues and cells, while high expression of SOX4 was observed in prostate cancer tissues and cells.

Results

Overexpression of miRNA-214-5p to prostate cancer cells significantly inhibited the proliferation of cancer cells, and the expression of SOX4 was inhibited in the transfected cell line. After transfection of miRNA-214-5p inhibitor into prostate cancer cells, the cell proliferation rate further increased. Meanwhile, overexpression of miRNA-214-5p effectively inhibited the expression of SOX4 downstream factors, including c-Myc, eIF4E, and CDK4. However, the specific knockdown of SOX4 through SOX4 shRNA significantly reduced the proliferation of prostate cancer cell lines.

Conclusions

miRNA-214-5 can inhibit the proliferation of prostate cancer cells by specifically targeting S0X4 and inhibiting the expression of growth factors downstream of this pathway.

1. Low expression of miRNA-214-5p is observed in prostate cancer cells.

2. miRNA-214-5p inhibits the proliferation of prostate cancer cells in vitro by targeting SOX4.

Emerging role of exosomes as biomarkers in cancer treatment and diagnosis

Cancer is a leading cause of death worldwide and cancer incidence and mortality are rapidly growing. These massive amounts of cancer patients require rapid diagnosis and efficient treatment strategies. However, the currently utilized methods are invasive and cost-effective. Recently, the effective roles of exosomes as promising diagnostic, prognostic, and predictive biomarkers have been revealed. Exosomes are membrane-bound extracellular vesicles containing RNAs, DNAs, and proteins, and are present in a wide array of body fluids. Exosomal cargos have shown the potential to detect various types of cancers at early stages with high sensitivity and specificity. They can also delivery therapeutic agents efficiently. In this article, an overview of recent advances in the research of exosomal biomarkers and their applications in cancer diagnosis and treatment has been provided. Furthermore, the advantages and challenges of exosomes as liquid biopsy targets are discussed and the clinical implications of using exosomal miRNAs have been revealed.

Modulating microRNAs in cancer: Next-generation therapies

MicroRNAs (miRNAs) are a class of endogenously expressed non-coding regulators of the genome with an ability to mediate a variety of biological and pathological processes. There is growing evidence demonstrating frequent dysregulation of microRNAs in cancer cells, which is associated with tumor initiation, development, migration, invasion, resisting cell death, and drug resistance. Studies have shown that modulation of these small RNAs is a novel and promising therapeutic tool in the treatment of a variety of diseases, especially cancer, due to their broad influence on multiple cellular processes. However, suboptimal delivery of the appropriate miRNA to the cancer sites, quick degradation by nucleases in the blood circulation, and off target effects have limited their research and clinical applications. Therefore, there is a pressing need to improve the therapeutic efficacy of miRNA modulators, while at the same time reducing their toxicities. Several delivery vehicles for miRNA modulators have been shown to be effective in vitro and in vivo. In this review, we will discuss the role and importance of miRNAs in cancer and provide perspectives on currently available carriers for miRNA modulation. We will also summarize the challenges and prospects for the clinical translation of miRNA-based therapeutic strategies.

Novel insights into exosomal circular RNAs: Redefining intercellular communication in cancer biology

Exosomes, a special type of membrane-bound extracellular vesicle regarded as an ideal carrier for intercellular messages, play an essential role in intercellular communication both locally and systematically. Recent studies have reported that circular RNAs (circRNAs), members of the noncoding RNA family, are abundant and stable in exosomes. As an essential mediator of intercellular communication within cancer cells or between cancer cells and noncancerous cells, exosomal circRNAs participate in multiple aspects of cancer. In this review, we summarize the biogenesis, properties and functions of exosomal circRNAs. In particular, we describe their intercellular transfer in the tumour microenvironment and associate their biological functions with different phenotypes of cancer. Finally, we discuss potential clinical applications in the future.

Integrated Analysis of Mutations, miRNA and mRNA Expression in Glioblastoma

Background

Glioblastoma multiforme (GBM) is a common, malignant brain tumor in adults, with a median survival of only 15–23 months. Organisms respond to disease stress through sophisticated mechanisms at the physiological, transcriptional and metabolic levels. However, the molecular regulatory networks responsible for occurrence, progression and recurrence of glioma have yet to be elucidated.

Methods

In this study, we sought to determine the cause of gliomas by developing an RNA-seq technique that analyzes mRNA and small RNA (sRNA) with the aim of discovering potential methods for precisely blocking key signaling pathways in occurrence, progression, and recurrence. The explication of mechanisms leading to GBM formation has become a feasible and promising new therapeutic method.

Results

GBM-associated genes were identified based on their expression during the disease stress response. Analysis of the inverse correlations between microRNAs (miRNAs) and target mRNAs revealed 43 mRNA–miRNA interactions during disease progression. BOC-SMO and BOC-RAS were found to promote the malignant progression of glioma. A total of 3088 differentially expressed genes were identified as involved in several biological processes, such as amino acid metabolism, protein transport associated with immune response, cell proliferation, and cell apoptosis. Fifteen miRNAs were also identified as being differentially expressed in GBM and control groups.

Conclusion

The results of this study provide an important foundation for understanding the pathogenesis of glioma and discovering new therapeutic targets.

Variability in the levels of exosomal miRNAs among human subjects could be explained by differential interactions of exosomes with the endothelium

Exosomes are 30-100 nm endosome-derived membrane vesicles, that contain specific RNA transcripts including mRNAs, and microRNAs (miRNAs) and have been implicated in cell-to-cell communication. Exosomal miRNAs in blood circulation have been attracting major interest as potential diagnostic and prognostic biomarkers in a variety of diseases including stroke, cancer, and inflammatory disorders. Despite the progress made in the utilization of circulating exosomal miRNAs as biomarkers for various human diseases and conditions, there are still difficulties in functionally utilizing such methods in the clinic due to the high variability observed among subjects. Attempts to use miRNA signatures have improved but have not eliminated the problem. Additionally, standardized laboratory practices may partially reduce variability but there is still an unknown biological factor that hinders the proper use of miRNAs as biomarkers. We hypothesize that this variability might be partially attributed to a differential interaction among circulating exosomes carrying those miRNAs with endothelial surface molecules that themselves may vary among individuals due to secondary conditions, for example, inflammation status. This differential interaction could potentially add variability to the level of the examined miRNA that is not directly attributed to the primary condition under study.

Integrating microRNA expression, miRNA-mRNA regulation network and signal pathway: a novel strategy for lung cancer biomarker discovery

Background

Since there are inextricably connections among molecules in the biological networks, it would be a more efficient and accurate research strategy to screen microRNA (miRNA) markers combining with miRNA-mRNA regulatory networks. The independent regulation mode is more “fragile” and “influential” than the co-regulation mode. miRNAs can be used as biomarkers if they can independently regulate hub genes with important roles in the PPI network, simultaneously the expression products of the regulated hub genes play important roles in the signaling pathways of related tissue diseases.

Methods

We collected miRNA expression of non-small cell lung cancer (NSCLC) from The Cancer Genome Atlas (TCGA) database and the Gene Expression Omnibus (GEO) database. Volcano plot and signal-to-noise ratio (SNR) methods were used to obtain significant differentially expressed (SDE) miRNAs from the TCGA database and GEO database, respectively. A human miRNA-mRNA regulatory network was constructed and the number of genes uniquely targeted (NOG) by a certain miRNA was calculated. The area under the curve (AUC) values were used to screen for clinical sensitivity and specificity. The candidate markers were obtained using the criteria of the top five maximum AUC values and NOG ≥ 3. The protein–protein interaction (PPI) network was constructed and independently regulated hub genes were obtained. Gene Ontology (GO) analysis and KEGG pathway analysis were used to identify genes involved in cancer-related pathways. Finally, the miRNA which can independently regulate a hub gene and the hub gene can participate in an important cancer-related pathway was considered as a biomarker. The AUC values and gene expression profile analysis from two external GEO datasets as well as literature validation were used to verify the screening capability and reliability of this marker.

Results

Fifteen SDE miRNAs in lung cancer were obtained from the intersection of volcano plot and SNR based on the GEO database and the TCGA database. Five miRNAs with the top five maximum AUC values and NOG ≥ 3 were screened out. A total of 61 hub genes were obtained from the PPI network. It was found that the hub gene GTF2F2 was independently regulated by miR-708-5p. Further pathway analysis indicated that GTF2F2 participates in protein expression by binding with polymerase II, and it can regulate transcription and accelerate tumor growth. Hence, miR-708-5p could be used as a biomarker. The good screening capability and reliability of miR-708-5p as a lung cancer marker were confirmed by AUC values and gene expression profiling of external datasets, and experimental literature. The potential mechanism of miR-708-5p was proposed.

Conclusions

This study proposes a new idea for lung cancer marker screening by integrating microRNA expression, regulation network and signal pathway. miR-708-5p was identified as a biomarker using this novel strategy. This study may provide some help for cancer marker screening.

Effects of exosomal miRNAs in the diagnosis and treatment of Alzheimer's disease

Alzheimer's disease (AD) is a progressive neurodegenerative disease. Exosomes are extracellular vesicles secreted by a variety of cells, and they participate in intercellular communication by transferring microRNA (miRNA) and other substances. Among the various internal and external factors involved in the occurrence and development of AD, exosome-derived miRNAs have become essential in the pathogenesis and treatment of AD. As nanocarriers of miRNA, exosomes are expected to become an important tool in the pathogenesis, diagnosis, and treatment of AD. This article reviews the roles of exosomal miRNAs in the pathophysiological process, diagnostic biomarkers and treatment of AD.

MicroRNA miR-30a inhibits cisplatin resistance in ovarian cancer cells through autophagy

We study whether microRNA miR-30a inhibits the autophagy through transforming growth factor (TGF)-β/Smad4 to generate cisplatin (DDP) resistance in ovarian cancer cells. The expression of miR-30a, Smad4, and TGF-β was detected in the serum of ovarian cancer patients and DDP-resistant cell lines (A2780) by quantitative real-time polymerase chain reaction (qRT-PCR). Computational search and western blotting were used to demonstrate the downstream target of miR-30a in ovarian cancer cells. Cell viability was measured with CCK8 assay. Apoptosis and autophagy of ovarian cancer cells were analyzed by flow cytometry and transmission electron microscopy, and the expressions of Beclin1 and LC3II protein were detected by western blotting. Expression of miR-30a was significantly decreased, while expressions of TGF-β and Smad4 mRNA were increased in serum of ovarian cancer patients after DDP chemotherapy as well as in DDP-resistant cells. Activation of autophagy contributed to DDP-resistance cells. Moreover, Bioinformatics software predicted Smad4 to be a target of miR-30a. Overexpression of miR-30a decreased the expression of Smad4 and TGF-β. Additionally, miR-30a-overexpressing inhibited DDP-induce autophagy and promoted DDP-resistant cell apoptosis. In conclusion, miR-30a mediates DDP resistance in ovarian cancer by inhibiting autophagy via the TGF-β/Smad4 pathway.

Small Extracellular Vesicles in Transplant Rejection

Small extracellular vesicles (sEV), which are released to body fluids (e.g., serum, urine) by all types of human cells, may stimulate or inhibit the innate and adaptive immune response through multiple mechanisms. Exosomes or sEV have on their surface many key receptors of immune response, including major histocompatibility complex (MHC) components, identical to their cellular origin. They also exhibit an ability to carry antigen and target leukocytes either via interaction with cell surface receptors or intracellular delivery of inflammatory mediators, receptors, enzymes, mRNAs, and noncoding RNAs. By the transfer of donor MHC antigens to recipient antigen presenting cells sEV may also contribute to T cell allorecognition and alloresponse. Here, we review the influence of sEV on the development of rejection or tolerance in the setting of solid organ and tissue allotransplantation. We also summarize and discuss potential applications of plasma and urinary sEV as biomarkers in the context of transplantation. We focus on the attempts to use sEV as a noninvasive approach to detecting allograft rejection. Preliminary studies show that both sEV total levels and a set of specific molecules included in their cargo may be an evidence of ongoing allograft rejection.

Small extracellular vesicles in cancer

Extracellular vesicles (EV) are lipid-bilayer enclosed vesicles in submicron size that are released from cells. A variety of molecules, including proteins, DNA fragments, RNAs, lipids, and metabolites can be selectively encapsulated into EVs and delivered to nearby and distant recipient cells. In tumors, through such intercellular communication, EVs can regulate initiation, growth, metastasis and invasion of tumors. Recent studies have found that EVs exhibit specific expression patterns which mimic the parental cell, providing a fingerprint for early cancer diagnosis and prognosis as well as monitoring responses to treatment. Accordingly, various EV isolation and detection technologies have been developed for research and diagnostic purposes. Moreover, natural and engineered EVs have also been used as drug delivery nanocarriers, cancer vaccines, cell surface modulators, therapeutic agents and therapeutic targets. Overall, EVs are under intense investigation as they hold promise for pathophysiological and translational discoveries. This comprehensive review examines the latest EV research trends over the last five years, encompassing their roles in cancer pathophysiology, diagnostics and therapeutics. This review aims to examine the full spectrum of tumor-EV studies and provide a comprehensive foundation to enhance the field. The topics which are discussed and scrutinized in this review encompass isolation techniques and how these issues need to be overcome for EV-based diagnostics, EVs and their roles in cancer biology, biomarkers for diagnosis and monitoring, EVs as vaccines, therapeutic targets, and EVs as drug delivery systems. We will also examine the challenges involved in EV research and promote a framework for catalyzing scientific discovery and innovation for tumor-EV-focused research.

Distinct Exosomal miRNA Profiles from BALF and Lung Tissue of COPD and IPF Patients

Chronic obstructive pulmonary disease (COPD) and idiopathic pulmonary fibrosis (IPF) are chronic, progressive lung ailments that are characterized by distinct pathologies. Early detection biomarkers and disease mechanisms for these debilitating diseases are lacking. Extracellular vesicles (EVs), including exosomes, are small, lipid-bound vesicles attributed to carry proteins, lipids, and RNA molecules to facilitate cell-to-cell communication under normal and diseased conditions. Exosomal miRNAs have been studied in relation to many diseases. However, there is little to no knowledge regarding the miRNA population of bronchoalveolar lavage fluid (BALF) or the lung-tissue-derived exosomes in COPD and IPF. Here, we determined and compared the miRNA profiles of BALF- and lung-tissue-derived exosomes of healthy non-smokers, smokers, and patients with COPD or IPF in independent cohorts. Results: Exosome characterization using NanoSight particle tracking and TEM demonstrated that the BALF-derived exosomes were ~89.85 nm in size with a yield of ~2.95 × 10¹⁰ particles/mL in concentration. Lung-derived exosomes were larger in size (~146.04 nm) with a higher yield of ~2.38 × 10¹¹ particles/mL. NGS results identified three differentially expressed miRNAs in the BALF, while there was one in the lung-derived exosomes from COPD patients as compared to healthy non-smokers. Of these, miR-122-5p was three- or five-fold downregulated among the lung-tissue-derived exosomes of COPD patients as compared to healthy non-smokers and smokers, respectively. Interestingly, there were a large number (55) of differentially expressed miRNAs in the lung-tissue-derived exosomes of IPF patients compared to non-smoking controls. Conclusions: Overall, we identified lung-specific miRNAs associated with chronic lung diseases that can serve as potential biomarkers or therapeutic targets.

MiR-10a-5p: A Promising Biomarker for Early Diagnosis and Prognosis Evaluation of Bladder Cancer

Introduction

MiRNAs play a critical role in carcinogenesis, among which miR-10a-5p has been reported in several types of human cancer. Nevertheless, the role of miR-10a-5p remain uncovered in bladder cancer (BCa).

Methods

We recruited 88 BCa patients and 36 healthy controls (HC) to form the training cohort, and other 120 BCa patients to form the validation cohort. The clinical samples were collected for analysis. The expression level of miR-10a-5p was evaluated using RT-qPCR. Receiver operating characteristic (ROC) curves were utilized to calculate diagnostic accuracy. Survival curves were generated to analyze survival outcomes. CCK-8 and transwell assays were conducted to test the cell proliferation, migration, and invasion capacities.

Results

MiR-10a-5p was upregulated in human BCa tissues and closely associated with advanced clinicopathological features, including advanced tumor grade, histological grade, and T stage. High expression of miR-10a-5p was associated with worse survival outcomes in BCa patients. Circulating plasma miR-10a-5p expression had the great performance power to discriminate BCa patients form HC patients before surgery, and to differentiate muscle invasive bladder cancer (MIBC) from non-muscle invasive bladder cancer (NMIBC). In addition, overexpression of miR-10a-5p could promote BCa cell proliferation, migration, and invasion.

Conclusion

This study indicates that miR-10a-5p is a crucial diagnostic and prognostic biomarker for BCa patients, and miR-10a-5p exerted a tumor promoting role during BCa cell progression.

Identification of cell cycle as the critical pathway modulated by exosome-derived microRNAs in gallbladder carcinoma

Gallbladder cancer (GBC), the most common malignancy in the biliary tract, is highly lethal malignant due to seldomly specific symptoms in the early stage of GBC. This study aimed to identify exosome-derived miRNAs mediated competing endogenous RNAs (ceRNA) participant in GBC tumorigenesis. A total of 159 differentially expressed miRNAs (DEMs) was identified as exosome-derived miRNAs, contains 34 upregulated exo-DEMs and 125 downregulated exo-DEMs based on the expression profiles in GBC clinical samples downloaded from the Gene Expression Omnibus database with the R package. Among them, 2 up-regulated exo-DEMs, hsa-miR-125a-3p and hsa-miR-4647, and 5 down-regulated exo-DEMs, including hsa-miR-29c-5p, hsa-miR-145a-5p, hsa-miR-192-5p, hsa-miR-194-5p, and hsa-miR-338-3p, were associated with the survival of GBC patients. Results of the gene set enrichment analysis showed that the cell cycle-related pathways were activated in GBC tumor tissues, mainly including cell cycle, M phase, and cell cycle checkpoints. Furthermore, the dysregulated ceRNA network was constructed based on the lncRNA-miRNA-mRNA interactions using miRDB, TargetScan, miRTarBase, miRcode, and starBase v2.0., consisting of 27 lncRNAs, 6 prognostic exo-DEMs, and 176 mRNAs. Together with prognostic exo-DEMs, the STEAP3-AS1/hsa-miR-192-5p/MAD2L1 axis was identified, suggesting lncRNA STEAP3-AS1, might as a sponge of exosome-derived hsa-miR-192-5p, modulates cell cycle progression via affecting MAD2L1 expression in GBC tumorigenesis. In addition, the biological functions of genes in the ceRNA network were also annotated by Gene Ontology and Kyoto Encyclopedia of Genes and Genomes. Our study promotes exploration of the molecular mechanisms associated with tumorigenesis and provide potential targets for GBC diagnosis and treatment.

The Roles of Exosomes as Future Therapeutic Agents and Diagnostic Tools for Glioma

Glioma is a common type of tumor originating in the brain. Glioma develops in the gluey supporting cells (glial cells) that surround and support nerve cells. Exosomes are extracellular vesicles that contain microRNAs, messenger RNA, and proteins. Exosomes are the most prominent mediators of intercellular communication, regulating, instructing, and re-educating their surrounding milieu targeting different organs. As exosomes' diameter is in the nano range, the ability to cross the blood-brain barrier, a crucial obstacle in developing therapeutics against brain diseases, including glioma, makes the exosomes a potential candidate for delivering therapeutic agents for targeting malignant glioma. This review communicates the current knowledge of exosomes' significant roles that make them crucial future therapeutic agents and diagnostic tools for glioma.

Biomolecules in cell-derived extracellular vesicle chariots as warriors to repair damaged tissues

In this review, we highlight the innovative applications of biomolecules from parent cell-derived extracellular vesicles (EVs) for tissue repair that have been developed in recent years. We evaluate the underlying mechanisms and therapeutic efficacy of each therapy. In previous literature reviews, it was most common to classify the use of EVs in tissue repair by disease type. This article reviews the role of three biomolecules in EVs in tissue repair. This review first summarizes the definitions and classifications of EVs. Then, the importance and significance of treating tissue damage with EVs are discussed. In particular, EV contents for tissue repair are three main types of biomolecules: proteins, RNAs and cell growth factors. The therapeutic and repair mechanisms of the biomolecules are discussed respectively. Finally, the development prospect and potential challenges of EV contents from highly differentiated cells as specific agents for tissue repair are summarized. When EVs are used to treat diseases such as tissue or organ damage, EVs play a role in delivery, and the real repair effect is effected by the various biomolecules carried by EVs. We believe that EV biomolecules have unparalleled advantages and clinical transformation potential for tissue repair and expect this review to inspire more intensive research work in this field.

Non-Coding RNAs: Master Regulators of Inflammasomes in Inflammatory Diseases

Emerging data indicates that non-coding RNAs (ncRNAs) represent more than just “junk sequences” of the genome and have been found to be involved in multiple diseases by regulating various biological process, including the activation of inflammasomes. As an important aspect of innate immunity, inflammasomes are large immune multiprotein complexes that tightly regulate the production of pro-inflammatory cytokines and mediate pyroptosis; the activation of the inflammasomes is a vital biological process in inflammatory diseases. Recent studies have emphasized the function of ncRNAs in the fine control of inflammasomes activation either by directly targeting components of the inflammasomes or by controlling the activity of various factors that control the activation of inflammasomes; consequently, ncRNAs may represent potential therapeutic targets for inflammatory diseases. Understanding the precise role of ncRNAs in controlling the activation of inflammasomes will help us to design targeted therapies for multiple inflammatory diseases. In this review, we summarize the regulatory role and therapeutic potential of ncRNAs in the activation of inflammasomes by focusing on a range of inflammatory diseases, including microbial infection, sterile inflammatory diseases, and fibrosis-related diseases. Our goal is to provide new ideas and perspectives for future research.

EVs delivery of miR-1915-3p improves the chemotherapeutic efficacy of oxaliplatin in colorectal cancer

PURPOSE

Oxaliplatin is a crucial component of the combinatorial chemotherapeutic standard of care for advanced colorectal cancer (CRC). Unfortunately, a serious barrier to effective oxaliplatin treatment is drug resistance due to epithelial-mesenchymal transitioning (EMT). Interestingly, stable oxaliplatin-resistant CRC cell lines show differential expression of miR-1915-3p; thus, this microRNA may represent a potential modifier of oxaliplatin resistance in CRC cells.

METHODS

miR-1915-3p was over-expressed in oxaliplatin-resistant CRC cells and a non-tumorigenic intestinal cell line (FHC) via lentiviral transduction. Extracellular vesicles (EVs) were purified from transduced FHC cells and co-incubated with CRC cells. Expression levels of miR-1915-3p and other RNA species were assessed by RT-qPCR, while protein expression levels were assessed by Western blotting. The effects of miR-1915-3p on CRC viability were evaluated by proliferation, apoptosis assays, and Transwell assays. Effects of miR-1915-3p over-expression on in vivo oxaliplatin sensitivity was tested via murine xenograft models.

RESULTS

miRNA-1915-3p decreased EMT marker expression in oxaliplatin-resistant CRC cell lines and in vivo. FHC cells were able to produce and secrete miR-1915-3p-containing EVs, which we employed to mediate miR-1915-3p delivery to oxaliplatin-resistant CRC cells and increase their oxaliplatin sensitivity in vivo and in vitro. Mechanistically, miR-1915-3p overexpression downregulated the EMT-promoting oncogenes 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 3 (PFKFB3) and ubiquitin carboxyl-terminal hydrolase 2 (USP2) as well as upregulated E-cadherin (a cell adhesion mediator). miR-1915-3p's effects on chemosensitivity and EMT were mediated by its regulation of PFKFB3 and USP2.

CONCLUSION

Exosomal delivery of miR-1915-3p can improve the chemotherapeutic efficacy of oxaliplatin in CRC cells by suppressing the EMT-promoting oncogenes PFKFB3 and USP2.

The Key Role of Exosomes on the Pre-metastatic Niche Formation in Tumors

Exosomes or other extracellular vesicles released from cells play an important role in cell-to-cell communication by transferring bio-information (DNA, coding/non-coding RNA, and proteins), which indicates parental cell status to recipient cells in the extracellular environment. Increasingly, evidence shows that tumor-derived exosomes mediate tumor pre-metastatic niche (PMN) remodeling to establish a supportive and receptive niche to promote tumor cell colonization and metastasis. Uptake of genetic information by target cells in the extracellular environment triggers epigenetic changes that contribute to PMN formation. Here, we provide a comprehensive overview of the current understanding of exosomes-mediated reprogramming of cells in PMN formation.

Downregulation of microRNA-6125 promotes colorectal cancer growth through YTHDF2-dependent recognition of N6-methyladenosine-modified GSK3β

BACKGROUND

MicroRNAs (miRNAs), the key regulator of gene expression, and N6-methyladenosine (m6A) RNA modification play a significant role in tumour progression. However, regulation of m6A-modified mRNAs by miRNAs in colorectal cancer (CRC), and its effect on progression of CRC, remains to be investigated.

METHODS

Expression of miR-6125 and YTH Domain-Containing Family Protein 2 (YTHDF2) was detected by western blotting and immunohistochemistry. The effects of miR-6125 and YTHDF2 on proliferative capacity of CRC cells were analysed using soft agar, ATP, CCK8 and EdU assays, and in animal experiments.

RESULTS

MiR-6125 expression was downregulated markedly in CRC, and expression correlated negatively with tumour size and prognosis. MiR-6125 targeted the 3'-UTR of YTHDF2 and downregulated the YTHDF2 protein, thereby increasing the stability of m6A-modified glycogen synthase kinase 3 beta (GSK3β) mRNA. Increased GSK3β protein levels inhibited the expression of Wnt/β-catenin/Cyclin D1 pathway-related proteins, leading to G0-G1 phase arrest and ultimately inhibiting the proliferation of CRC cells.

CONCLUSIONS

MiR-6125 regulates YTHDF2 and thus plays a critical role in regulating the Wnt/β-catenin pathway, thereby affecting the growth of CRC. Collectively, these results suggest that miR-6125 and YTHDF2 are potential targets for treatment of CRC.

Exosomal miR-4488 and miR-1273g-5p inhibit the epithelial-mesenchymal transition of transforming growth factor β2-mediated retinal pigment epithelial cells by targeting ATP-binding cassette A4

Exosomal microRNAs (miRNAs) have been shown to be involved in the regulation of many disease progression, including proliferative vitreoretinopathy (PVR). However, the roles of exosomal miR-4488 and miR-1273g-5p in PVR progression have not been demonstrated. Transforming growth factor β2 (TGF-β2)-induced ARPE-19 cells were used to stimulate the epithelial-mesenchymal transition (EMT) of cells. Exosomes derived from TGF-β2-induced ARPE-19 cells were identified by transmission electron microscopy and nanoparticle tracking analysis. The expression levels of miR-4488, miR-1273g-5p and ATP-binding cassette A4 (ABCA4) were measured by quantitative real-time PCR. The promotion levels of exosomes markers, EMT markers, apoptosis markers and ABCA4 were determined by western blot analysis. The migration, invasion and apoptosis of cells were determined by transwell assay, wound healing assay and flow cytometry. Our data showed that miR-4488 and miR-1273g-5p were lowly expressed in TGF-β2-induced ARPE-19 cells. Overexpressed exosomal miR-4488 and miR-1273g-5p could inhibit the EMT, migration, invasion, and promote apoptosis in TGF-β2-induced ARPE-19 cells. In addition, ABCA4 was a target of miR-4488 and miR-1273g-5p. Overexpressed ABCA4 also could reverse the negatively regulation of exosomal miR-4488 and miR-1273g-5p on the EMT, migration, and invasion of TGF-β2-induced ARPE-19 cells. In conclusion, our data showed that exosomal miR-4488 and miR-1273g-5p could inhibit TGF-β2-stimulated EMT in ARPE-19 cells through targeting ABCA4.

Exosomes from 3T3-J2 promote expansion of tracheal basal cells to facilitate rapid epithelization of 3D-printed double-layer tissue engineered trachea

Functional epithelization plays a pivotal role in maintaining long-term lumen patency of tissue-engineered trachea (TET). Due to the slow migration of autologous epithelium, spontaneous epithelization process of transplanted TET is always tardive. Seeding tracheal basal cells (TBCs) on TET before transplantation might be favorable for accelerating epithelization, but rapid expansion of TBCs in vitro is still relatively intractable. In this study, we proposed a promising expansion strategy which enables the TBCs to proliferate rapidly in vitro. TBCs were isolated from the autologous tracheal mucosae of rabbit, and co-cultured with exosomes derived from 3T3-J2 cells. After co-culture with exosomal component, TBCs could vigorously proliferate in vitro and retained their multi-potency. It was in stark contrast to that the single-cultured TBCs could only be expand to passage 2 in about 30 days, moreover, the most majority of single-cultured cells entered late apoptotic stage. On the other hand, a bionic tubular double-layer scaffold with good mechanical property and bio-compatibility was designed and fabricated by 3D printing technology. Then TET with bi-lineage cell-type was constructed in vitro by implanting autologous chondrocytes on the outer-layer of scaffold, and TBCs on the inner-layer, respectively. And then TET was pre-vascularized in vivo, and pedicled transplanted to restore long-segmental defect in recipient rabbits. It was found that the chondrocytes and TBCs seeded on double-layer scaffolds developed well as expected. And almost complete coverage with ciliated epitheliums was observed on the lumen surface of TET 2-week after operation, in comparison with that the epithelization of TET without pre-seeding of TBCs accomplished nearly 2-month after operation. In conclusion, the promising expansion strategy of TBCs together with 3D-printed double-layer scaffolds facilitate the rapid epithelization process of transplanted TET, which might be of vital significance for clinical and translational medicine.

Biosensor-based assay of exosome biomarker for early diagnosis of cancer

Cancer imposes a severe threat to people's health and lives, thus pressing a huge medical and economic burden on individuals and communities. Therefore, early diagnosis of cancer is indispensable in the timely prevention and effective treatment for patients. Exosome has recently become an attractive cancer biomarker in noninvasive early diagnosis because of the unique physiology and pathology functions, which reflects remarkable information regarding the cancer microenvironment, and plays an important role in the occurrence and evolution of cancer. Meanwhile, biosensors have gained great attention for the detection of exosomes due to their superior properties, such as convenient operation, real-time readout, high sensitivity, and remarkable specificity, suggesting promising biomedical applications in the early diagnosis of cancer. In this review, the latest advances of biosensors regarding the assay of exosomes were summarized, and the superiorities of exosomes as markers for the early diagnosis of cancer were evaluated. Moreover, the recent challenges and further opportunities of developing effective biosensors for the early diagnosis of cancer were discussed.