Downregulation of circulating exosomal miR-638 predicts poor prognosis in colon cancer patients

Research progress of CTC, ctDNA, and EVs in cancer liquid biopsy

Circulating tumor cells (CTCs), circulating tumor DNA (ctDNA), and extracellular vehicles (EVs) have received significant attention in recent times as emerging biomarkers and subjects of transformational studies. The three main branches of liquid biopsy have evolved from the three primary tumor liquid biopsy detection targets-CTC, ctDNA, and EVs-each with distinct benefits. CTCs are derived from circulating cancer cells from the original tumor or metastases and may display global features of the tumor. ctDNA has been extensively analyzed and has been used to aid in the diagnosis, treatment, and prognosis of neoplastic diseases. EVs contain tumor-derived material such as DNA, RNA, proteins, lipids, sugar structures, and metabolites. The three provide different detection contents but have strong complementarity to a certain extent. Even though they have already been employed in several clinical trials, the clinical utility of three biomarkers is still being studied, with promising initial findings. This review thoroughly overviews established and emerging technologies for the isolation, characterization, and content detection of CTC, ctDNA, and EVs. Also discussed were the most recent developments in the study of potential liquid biopsy biomarkers for cancer diagnosis, therapeutic monitoring, and prognosis prediction. These included CTC, ctDNA, and EVs. Finally, the potential and challenges of employing liquid biopsy based on CTC, ctDNA, and EVs for precision medicine were evaluated.

Exploring the Versatility of Exosomes: A Review on Isolation, Characterization, Detection Methods, and Diverse Applications

Extracellular vesicles (EVs) are crucial mediators of intercellular communication and can be classified based on their physical properties, biomolecular structure, and origin. Among EVs, exosomes have garnered significant attention due to their potential as therapeutic and diagnostic tools. Exosomes are released via fusion of multivesicular bodies on plasma membranes and can be isolated from various biofluids using methods such as differential ultracentrifugation, immune affinity capture, ultrafiltration, and size exclusion chromatography. Herein, an overview of different techniques for exosome characterization and isolation, as well as the diverse applications of exosome detection, including their potential use in drug delivery and disease diagnosis, is provided. Additionally, we discuss the emerging field of exosome detection by sensors, which offers an up-and-coming avenue for point-of-care diagnostic tools development. Overall, this review aims to provide a exhaustive and up-to-date summary of the current state of exosome research.

Prognostic modelling of colorectal cancer based on oxidative stress-related genes

BACKGROUND

Colon cancer is one of the most prevalent cancers of the digestive tract. There is mounting evidence that genes associated with oxidative stress might affect the tumour immune microenvironment during tumour growth, maintenance, and treatment response. However, how oxidative stress-related genes affect prognostic importance, tumour microenvironment features, and treatment outcomes in colon cancer patients has not been fully elucidated.

METHODS

The Cancer Genome Atlas (TCGA) dataset was used to construct a signature model and nomogram using step and Cox regression approaches to investigate how gene expression affected immunological responses to colon cancer, including the degree of immune infiltration, MSI, and drug sensitivity.

RESULTS AND CONCLUSIONS

The nomogram and the signature model had strong prognostic potential for colon cancer, with gene expression highly correlated with multiple immune cells. The first signature model and nomogram including oxidative stress-related genes were constructed for use in clinical decision-making. In addition, SRD5A1, GSR, TXN, TRAF2 and TRAP1 were identified as potential biomarkers for colon cancer diagnosis and indicators for immunotherapy.

Circulating exosomal microRNAs as potential prognostic biomarkers in gastrointestinal cancers: a systematic review and meta-analysis

BACKGROUND

Recent reports suggested that circulating exosomal microRNAs (exomiRs) may serve as non-invasive prediction biomarkers in gastrointestinal (GI) cancers, yet their clinicopathological and prognostic values need to be more clarified. Hence, the present meta-analysis was aimed to quantitatively assess the evidence regarding the association between circulating exomiRs and prognosis in GI cancer patients.

METHODS

A comprehensive search was carried out in prominent literature databases, including PubMed, ISI Web of Science, Scopus, and Embase. Odds ratios (ORs) or hazard ratios (HRs) with 95% confidence intervals (CIs) were gathered to evaluate the strength of the association. The quality assessment was investigated through the Newcastle-Ottawa Scale (NOS) and publication bias via Eggers' test and funnel plots.

RESULTS

A total of 47 studies, comprising of 4881 patients, were considered eligible for this meta-analysis. Both up-regulated and down-regulated circulating exomiRs are significantly associated with differentiation (HR = 1.353, P = 0.015; HR = 1.504, P = 0.016), TNM stage (HR = 2.058, P < 0.001; HR = 2.745, P < 0.001), lymph node metastasis (HR = 1.527, P = 0.004; HR = 2.009, P = 0.002), distant metastasis (HR = 2.006, P < 0.001; HR = 2.799, P = 0.002), worse overall survival (OS) (HR = 2.053, P < 0.001; HR = 1.789, P = 0.001) and poorer disease/relapse/progression-free survival (DFS/RFS/PFS) (HR = 2.086, P < 0.001; HR = 1.607, P = 0.001) in GI cancer patients, respectively. In addition, subgroup analyses based on seven subcategories indicated the robustness of the association. The majority of findings were lack of publication bias except for the association between up-regulated exomiRs and OS or DFS/RFS/PFS and for the down-regulated exomiRs and TNM stage.

CONCLUSION

This study supports that up- and down-regulated circulating exomiRs are associated with poorer survival outcomes and could be served as potential prognostic biomarkers in GI cancers. Given the limitations of the current findings, such as significant heterogeneity, more investigations are needed to fully clarify the exomiRs prognostic role.

The Role of Exosomes in Human Carcinogenesis and Cancer Therapy-Recent Findings from Molecular and Clinical Research

Exosomes are biological nanoscale spherical lipid bilayer vesicles, 40-160 nm in diameter, produced by most mammalian cells in both physiological and pathological conditions. Exosomes are formed via the endosomal sorting complex required for transport (ESCRT). The primary function of exosomes is mediating cell-to-cell communication. In terms of cancer, exosomes play important roles as mediators of intercellular communication, leading to tumor progression. Moreover, they can serve as biomarkers for cancer detection and progression. Therefore, their utilization in cancer therapies has been suggested, either as drug delivery carriers or as a diagnostic tool. However, exosomes were also reported to be involved in cancer drug resistance via transferring information of drug resistance to sensitive cells. It is important to consider the current knowledge regarding the role of exosomes in cancer, drug resistance, cancer therapies, and their clinical application in cancer therapies.

The Clinical Value of Blood miR-654-5p, miR-126, miR-10b, and miR-144 in the Diagnosis of Colorectal Cancer

Colorectal cancer (CRC) is the third cause of cancer-related death and the fourth most frequently diagnosed cancer across the globe. The objective of this study is to obtain novel and effective diagnostic markers to enrich CRC diagnosis methods. Herein, exosomal miRNA expression data of CRC and normal blood were subjected to XGBoost algorithm, and 5 miRNAs related to CRC diagnosis were primarily confirmed. Then multilayer perceptron (MLP) classifiers were constructed based on different subsets. Via integrated feature selection (IFS), we noticed that the MLP classifier constructed by the first four miRNAs (miR-654-5p, miR-126, miR-10b, and miR-144) had the highest Matthews correlation coefficient (MCC). Subsequently, principal component analysis (PCA) for dimensionality reduction was performed on samples based on the miR-654-5p, miR-126, miR-10b, and miR-144 expression data. The signature based on these four feature miRNAs, as the analysis indicated, could effectively distinguish CRC samples from normal samples. Further, we extracted the exosomes from clinical blood samples and applied qRT-PCR analysis, which revealed that the expression of these four feature miRNAs was in the trend of that in the test set. Collectively, these four feature miRNAs might be tumor biomarkers in the serum, and our study offers innovative thinking on early-stage CRC diagnosis.

Recent Advances in Detection for Breast-Cancer-Derived Exosomes

Breast cancer is the most common malignant tumor in women, its incidence is secret, and more than half of the patients are diagnosed in the middle and advanced stages, so it is necessary to develop simple and efficient detection methods for breast cancer diagnosis to improve the survival rate and quality of life of breast cancer patients. Exosomes are extracellular vesicles secreted by all kinds of living cells, and play an important role in the occurrence and development of breast cancer and the formation of the tumor microenvironment. Exosomes, as biomarkers, are an important part of breast cancer fluid biopsy and have become ideal targets for the early diagnosis, curative effect evaluation, and clinical treatment of breast cancer. In this paper, several traditional exosome detection methods, including differential centrifugation and immunoaffinity capture, were summarized, focusing on the latest research progress in breast cancer exosome detection. It was summarized from the aspects of optics, electrochemistry, electrochemiluminescence and other aspects. This review is expected to provide valuable guidance for exosome detection of clinical breast cancer and the establishment of more reliable, efficient, simple and innovative methods for exosome detection of breast cancer in the future.

Extracellular vesicles and particles impact the systemic landscape of cancer

Intercellular cross talk between cancer cells and stromal and immune cells is essential for tumor progression and metastasis. Extracellular vesicles and particles (EVPs) are a heterogeneous class of secreted messengers that carry bioactive molecules and that have been shown to be crucial for this cell-cell communication. Here, we highlight the multifaceted roles of EVPs in cancer. Functionally, transfer of EVP cargo between cells influences tumor cell growth and invasion, alters immune cell composition and function, and contributes to stromal cell activation. These EVP-mediated changes impact local tumor progression, foster cultivation of pre-metastatic niches at distant organ-specific sites, and mediate systemic effects of cancer. Furthermore, we discuss how exploiting the highly selective enrichment of molecules within EVPs has profound implications for advancing diagnostic and prognostic biomarker development and for improving therapy delivery in cancer patients. Altogether, these investigations into the role of EVPs in cancer have led to discoveries that hold great promise for improving cancer patient care and outcome.

Harnessing the Therapeutic Potential of Extracellular Vesicles for Biomedical Applications Using Multifunctional Magnetic Nanomaterials

Extracellular vesicles (e.g., exosomes) carrying various biomolecules (e.g., proteins, lipids, and nucleic acids) have rapidly emerged as promising platforms for many biomedical applications. Despite their enormous potential, their heterogeneity in surfaces and sizes, the high complexity of cargo biomolecules, and the inefficient uptake by recipient cells remain critical barriers for their theranostic applications. To address these critical issues, multifunctional nanomaterials, such as magnetic nanomaterials, with their tunable physical, chemical, and biological properties, may play crucial roles in next-generation extracellular vesicles (EV)-based disease diagnosis, drug delivery, tissue engineering, and regenerative medicine. As such, one aims to provide cutting-edge knowledge pertaining to magnetic nanomaterials-facilitated isolation, detection, and delivery of extracellular vesicles and their associated biomolecules. By engaging the fields of extracellular vesicles and magnetic nanomaterials, it is envisioned that their properties can be effectively combined for optimal outcomes in biomedical applications.

The Value of Serum miR-139-3p Expression Level in Predicting Postoperative Survival of Colon Cancer Patients

Background

To explore the value of serum miR-139-3p expression level in predicting postoperative survival of colon cancer patients.

Methods

We selected 158 cases enrolled in our hospital from January 2017 to December 2019. Using real-time fluorescence quantitative PCR, the expression extents of serum miR-139-3p among patients suffering from colon cancer were detected. The enrollment of patients was performed in the high or low miR-139-3p group on the basis of the cutoff value determined by ROC curve analysis. The risk elements influencing the postoperative survival of colon cancer patients were analyzed by the Kaplan–Meier approach and univariate and multivariate Cox regression models.

Results

Compared with control group, significantly lower expression level of serum miR-139-3p was shown in colon cancer group (P < 0.05). Its low expression of miR-139-3p was associated with TNM stage, degree of differentiation, tumor sizes, lymph node metastasis and vascular infiltration in patients with colon cancer (all P < 0.05), which was also significantly associated with short survival time of colon cancer patients (P < 0.05). Multivariate Cox regression model analysis displayed that TNM phase, lymph node metastasis and miR-139-3p <2.17 were independent risk elements affecting postoperative survival (P < 0.05).

Conclusion

The low expression level of miR-139-3p is related to the short survival time of colon cancer patients, and it is expected to be used as a biological indicator to predict the postoperative survival of colon cancer.

The Incredible Potential of Exosomes as Biomarkers in the Diagnosis of Colorectal Cancer

Colorectal cancer (CRC) is common cancer that is one of the leading causes of cancerrelated deaths around the world. The creation of new biomarkers for this disease is an important public health strategy for lowering the disease's mortality rate. According to new research, exosomes may be important sources of biomarkers in CRC. Exosomes are nanometer-sized membrane vesicles (30-200 nm) secreted by normal and cancer cells that transport RNA and proteins between cells and are thought to help with intercellular communication. Exosomes have been linked to CRC initiation and progression, and some differentially expressed RNAs and proteins in exosomes have been identified as potential cancer detection candidates. As a result, studying the relationship between exosomes and CRC may aid in the development of new biomarkers for the disease. This article discusses the importance of exosomes as biomarkers in the diagnosis of CRC, as well as their use in the treatment of CRC metastasis, chemoresistance, and recrudescence. The benefits and drawbacks of using exosomes as tumour markers are also discussed.

The Role of MiRNA in Cancer: Pathogenesis, Diagnosis, and Treatment

Cancer is also determined by the alterations of oncogenes and tumor suppressor genes. These gene expressions can be regulated by microRNAs (miRNA). At this point, researchers focus on addressing two main questions: "How are oncogenes and/or tumor suppressor genes regulated by miRNAs?" and "Which other mechanisms in cancer cells are regulated by miRNAs?" In this work we focus on gathering the publications answering these questions. The expression of miRNAs is affected by amplification, deletion or mutation. These processes are controlled by oncogenes and tumor suppressor genes, which regulate different mechanisms of cancer initiation and progression including cell proliferation, cell growth, apoptosis, DNA repair, invasion, angiogenesis, metastasis, drug resistance, metabolic regulation, and immune response regulation in cancer cells. In addition, profiling of miRNA is an important step in developing a new therapeutic approach for cancer.

Diagnostic Role of Extracellular Vesicles in Cancer: A Comprehensive Systematic Review and Meta-Analysis

Background: Cancer-derived extracellular vesicles (EVs) are regarded to have significant function in most steps during cancer progression. This meta-analysis aims to investigate the accuracy of EVs as a biomarker in cancer diagnosis.

Methods: The diagnostic efficacy of EVs for different cancers was assessed using pooled sensitivity and specificity, diagnostic odds ratio (DOR), and overall area under the curve (AUC) of the summary receiver operating characteristic (SROC). The positive likelihood ratio (PLR) and negative likelihood ratio (NLR) were verified to estimate the diagnostic efficacy of EV at a clinical level.

Results: In all, 6,183 cancer patients and 2,437 healthy controls from 75 eligible studies reported in 42 publications were included in the study. The overall pooled sensitivity, specificity, PLR, NLR, and DOR were 0.62 (95% CI: 0.60–0.63), 0.76 (95% CI: 0.75–0.78), 3.07 (95% CI: 2.52–3.75), 0.34 (95% CI: 0.28–0.41), and 10.98 (95% CI: 7.53–16.00), respectively. Similarly, the AUC of the SROC was 0.88, indicating a high conservation of EVs as an early diagnostic marker. Furthermore, subgroup analysis suggested that the use of small EVs as a biomarker was more accurate in serum-based samples of nervous system cancer (p < 0.001). As a result, ultracentrifugation and quantification and size determination methods, such as Western blotting and ELISA were the most reliable identification methods for EV detection. We also indicated that increased secretion of EVs made them a capable biomarker for diagnosing cancer in elderly European individuals.

Conclusions: Our study provides evidence that EVs are a promising non-invasive biomarker for cancer diagnosis. Well-designed cohort studies should be conducted to warrant the clinical diagnostic value of EVs.

Exosomal Components and Modulators in Colorectal Cancer: Novel Diagnosis and Prognosis Biomarkers

The relatively high incidence and mortality rates for colorectal carcinoma (CRC) make it a formidable malignant tumor. Comprehensive strategies have been applied to predict patient survival and diagnosis. Various clinical regimens have also been developed to improve the therapeutic outcome. Extracellular vesicles (EVs) are recently proposed cellular structures that can be produced by natural or artificial methods and have been extensively studied. In addition to their innate functions, EVs can be manipulated to be drug carriers and exert many biological functions. The composition of EVs, their intravesicular components, and the surrounding tumor microenvironment are closely related to the development of colorectal cancer. Determining the expression profiles of exocytosis samples and using them as indicators for selecting effective combination therapy is an indispensable direction for EV study and should be regarded as a novel prediction platform in addition to cancer stage, prognosis, and other clinical assessments. In this review, we summarize the function, regulation, and application of EVs in the colon cancer research field. We provide an update on and discuss potential values for clinical applications of EVs. Moreover, we illustrate the specific markers, mediators, and genetic alterations of EVs in colorectal carcinogenesis. Furthermore, we outline the vital markers present in the EVs and discuss their plausible uses in colon cancer patient therapy in combination with the currently used clinical strategies. The development and application of these EVs will significantly improve the accuracy of diagnosis, lead to more precise prognoses, and may lead to the improved treatment of colorectal cancer.

Circular RNA TADA2A promotes proliferation and migration via modulating of miR‑638/KIAA0101 signal in non‑small cell lung cancer

Accumulating evidence indicates that circular (circ)RNAs exhibit complex functions in diverse malignant tumors, including non-small cell lung cancer (NSCLC). The role of the circRNA transcription adaptor 2A (circTADA2A) in NSCLC remains unclear. The expression, function and mechanism of circTADA2A in NSCLC development were investigated in the present study. The results revealed that circTADA2A was upregulated in NSCLC, and that knockdown of circTADA2A inhibited cell proliferation and migration in the NSCLC cell lines A549 and H1299. Functional assays demonstrated that circTADA2A promoted proliferation and migration via interacting with microRNA (miR)-638. Bioinformatics and reverse transcription-quantitative PCR assay confirmed that miR-638 was expressed at low levels in NSCLC. In addition, it was found that miR-638 served a tumor-suppressive role and suppressed proliferation and migration via PCNA clamp associated factor (KIAA0101) inhibition in A549 and H1299 cells. Lastly, it was verified that circTADA2A promoted cell proliferation and migration, at least partially, via miR-638/KIAA0101 signaling in A549 and H1299 cells. In summary, the present study showed that circTADA2A promoted NSCLC cell proliferation and migration via modulating miR-638/KIAA0101 signaling.

Exosomes: Isolation, characterization, and biomedical applications

Exosomes are nano-sized bioactive vesicles of 30-150 nm in diameter. They are secreted by exocytosis of nearly all type of cells in to the extracellular fluid. Thereby, they can be found in many biological fluids. Exosomes regulate intracellular communication between cells via delivery of their cargo which include lipids, proteins, and nucleic acid. Many desirable features of exosomes made them promising candidates in several therapeutic applications. In this review, we discuss the use of exosomes as diagnostic tools and their possible biomedical applications. Additionally, current techniques used for isolation, purification, and characterization of exosomes from both biological fluids and in vitro cell cultures were discussed.

Exosomal microRNAs in colorectal cancer: Overcoming barriers of the metastatic cascade (Review)

The journey of cancer cells from a primary tumor to distant sites is a multi-step process that involves cellular reprogramming, the breaking or breaching of physical barriers and the preparation of a pre-metastatic niche for colonization. The loss of adhesion between cells, cytoskeletal remodeling, the reduction in size and change in cell shape, the destruction of the extracellular matrix, and the modification of the tumor microenvironment facilitate migration and invasion into surrounding tissues. The promotion of vascular leakiness enables intra- and extravasation, while angiogenesis and immune suppression help metastasizing cells become established in the new site. Tumor-derived exosomes have long been known to harbor microRNAs (miRNAs or miRs) that help prepare secondary sites for metastasis; however, their roles in the early and intermediate steps of the metastatic cascade are only beginning to be characterized. The present review article presents a summary and discussion of the miRNAs that form part of colorectal cancer (CRC)-derived exosomal cargoes and which play distinct roles in epithelial to mesenchymal plasticity and metastatic organotropism. First, an overview of epithelial-to-mesenchymal transition (EMT), metastatic organotropism, as well as exosome biogenesis, cargo sorting and uptake by recipient cells is presented. Lastly, the potential of these exosomal miRNAs as prognostic biomarkers for metastatic CRC, and the blocking of these as a possible therapeutic intervention is discussed.

Prognostic and clinicopathological significance of miR-638 in cancer patients: A meta-analysis

INTRODUCTION

MiR-638 is believed to be involved in human cancers. However, the prognostic value of miR-638 in human carcinomas is controversial and inconclusive. Therefore, we conducted this meta-analysis to investigate the association between miR-638 expression and clinical outcomes in the patients with various cancers.

METHODS

We searched Pubmed, Embase, Wanfang, and the China National Knowledge Infrastructure (CNKI) up to September 1, 2020 to identify relevant studies. Hazard ratios (HRs) and odds ratios (ORs) with 95% confidence intervals (CIs) were used to correlate expression of miR-638 with prognosis and clinicopathological features.

RESULTS

A total of 18 studies involving 1886 patients were included in the meta-analysis. The results revealed that low miR-638 expression was significantly correlated with poor overall survival (OS) (HR = 2.09, 95% CI: 1.46-2.98, P < .001), but not with disease-free survival (DFS) (HR = 1.71, 95% CI: 0.31-9.56, P = .540). Subgroup analysis found that low miR-638 expression was associated with worse OS in patients with digestive system cancer (HR = 2.47, 95% CI: 1.85-3.30, P < .001), the reported directly from articles group (HR = 2.12, 95% CI: 1.34-3.33, P < .001), survival curves group (HR = 2.02, 95% CI: 1.07-3.80, P = .029), in studies with sample size ≥100 (HR = 2.12, 95% CI: 1.34-3.35, P = .001), and in studies with sample size <100 (HR = 2.02, 95%CI: 1.09-3.75, P = .025). Moreover, cancer patients with low miR-638 expression were prone to tumor size (OR = 1.47, 95% CI: 1.03-2.09, P = .035), earlier lymph node metastasis (present vs absent, OR = 2.26, 95% CI: 1.63-3.14, P < .001), earlier distant metastasis (present vs absent, OR = 2.60, 95% CI: 1.45-4.67, P < .001), TNM stage (III-IV vs I-II, OR = 2.01, 95% CI: 1.35-2.99, P = .001), and portal vein invasion (present vs absent, OR = 4.39, 95% CI:2.23-8.64, P < .001), but not associated with age, gender, tumor differentiation, and vascular invasion.

CONCLUSIONS

MiR-638 may serve as a promising indicator in the prediction of prognosis and clinicopathological features in patients with different kinds of cancers.

Bioinformatic analysis reveals an exosomal miRNA-mRNA network in colorectal cancer

BACKGROUND

Exosomes play important roles in angiogenesis, drug resistance, and metastasis of colorectal cancer (CRC), but the underlying mechanism has seldom been reported. Herein, our study aimed to reveal an exosomal miRNA-mRNA network involved in CRC by performing bioinformatical analysis.

METHODS

The mRNA and miRNA data of colon adenocarcinoma and rectal adenocarcinoma were downloaded from The Cancer Genome Atlas (TCGA) database, and exosomal miRNAs data were downloaded from the GEO dataset GSE39833. The differential expression analysis was performed using "limma" and "edgeR". Target mRNAs of miRNAs were predicted using FunRich 3.1.3, miRNAtap and multiMiR. The candidate mRNAs and exosomal miRNAs were obtained by intersecting two groups of differentially expressed miRNAs and intersection of the differential expressed mRNAs and the target mRNAs, respectively. Key mRNAs and exosomal miRNAs were identified by the least absolute shrinkage and selection operator regression analysis, and used to construct the exosomal miRNA-mRNA network. The network verified was by receiver operating characteristic curve, GEPIA and LinkedOmics. Functional enrichment analysis was also performed for studied miRNAs and mRNAs.

RESULTS

A total of 6568 differentially expressed mRNAs and 531 differentially expressed miRNAs from TCGA data, and 166 differentially expressed exosomal miRNAs in GSE39833 dataset were identified. Next, 16 key mRNAs and five key exosomal miRNAs were identified from the 5284 candidate mRNAs and 61 candidate exosomal miRNAs, respectively. The exosomal miRNA-mRNA network with high connectivity contained 13 hub mRNAs (CBFB, CDH3, ETV4, FOXQ1, FUT1, GCNT2, GRIN2D, KIAA1549, KRT80, LZTS1, SLC39A10, SPTBN2, and ZSWIM4) and five hub exosomal miRNAs (hsa-miR-126, hsa-miR-139, hsa-miR-141, hsa-miR-29c, and hsa-miR-423). The functional annotation revealed that these hub mRNAs were mainly involved in the regulation of B cell receptor signaling pathway and glycosphingolipid biosynthesis related pathways. All hub mRNAs and hub exosomal miRNAs exhibited high diagnosis value for CRC. Furthermore, the association of the hub mRNAs with overall survival, stages, and MSI phenotype of CRC revealed their important roles in CRC progression.

CONCLUSION

This study constructed an exosomal miRNA-mRNA network which may play crucial roles in the carcinogenesis and progression of CRC, thus providing potential diagnostic biomarkers and therapeutic targets for CRC.

MicroRNA-638 induces apoptosis and autophagy in human liver cancer cells by targeting enhancer of zeste homolog 2 (EZH2)

Liver cancer is of the devastating human cancers and its incidence is increasing at an alarming rate. The clinical outcomes are far from descent due to lack of efficient therapeutic targets and chemotherapeutic agents. Studies have revealed the therapeutic implications of microRNAs in the management of different human cancers. This study was designed to explore the role and therapeutic potential of miR-638 in liver cancer via modulation of zeste homolog 2 (EZH2). The results revealed significant (P < 0.05) downregulation of miR-638 in human liver cancer tissues and cell lines. Overexpression of miR-638 led to a significant (P < 0.05) decline in liver cancer cell proliferation. Nonetheless, inhibition of miR-638 could promote the proliferation of the human liver cancer cells. The DAPI and annexin V/PI staining assays revealed that miR-638 induces apoptosis in human liver cancer cells which was accompanied by enhancement of Bax and depletion of Bcl-2 expression. Furthermore, miR-638 overexpression also leads to a significant (P < 0.05) increase of autophagosomes and autolysosomes in liver cancer cells suggestive of autophagy. The induction of autophagy was further confirmed by increase and decrease in expression of LC3B-II and Beclin-1 proteins, respectively. In contrary, inhibition of miR-638 prevented both apoptosis and autophagy of the liver cancer cells. In silico analysis and the dual luciferase assay revealed EZH2 as the molecular target of miR-638 at post-transcriptional level. The qRT-PCR showed that EZH2 to be significantly (P < 0.05) upregulated in the human liver cancer tissues and cell lines. However, the expression of EZH2 was considerably suppressed upon miR-638 overexpression in SNU-423 cells. Taken together, these findings suggest the tumor-suppressive role of miR-638/EZH2 axis liver cancer and point towards the potential of miR-638 as therapeutic target in the treatment of liver cancer.

Hsa_circ_0001869 promotes NSCLC progression via sponging miR-638 and enhancing FOSL2 expression

Accumulating studies suggest that circular RNAs (circRNAs) function as key regulators in human cancers. We found that hsa_circ_0001869 participated in non-small cell lung cancer (NSCLC) progression. However, its expression and function during NSCLC remain unknown. The data advised that hsa_circ_0001869 expression was increased in NSCLC cell lines and tissues. High hsa_circ_0001869 expression had negatively correlation with the NSCLC patients prognosis. Bioinformatics and luciferase report analyses confirmed that miR-638 and FOSL2 were hsa_circ_0001869 downstream target. hsa_circ_0001869 downregulation decreased tumor proliferation, invasion and migration by promoting miR-638 expression and decreasing FOSL2 expression. As a result of overexpression of FOSL2 or silencing of miR-638, the recovery of proliferation, migration, and invasion after hsa_circ_0001869 silencing. Overexpression of FOSL2 also led to recovery of migration, invasion and proliferation after upregulation of miR-638. In vivo studies confirmed that overexpression of FOSL2 or silencing of miR-638 led to the recovery of tumor growth ability regarding A549 cells after hsa_circ_0001869 knockdown. Present investigation discovered that hsa_circ_0001869 enhanced NSCLC progression via sponging miR-638 and promoting FOSL2 expression. hsa_circ_0001869 downregulation suppressed tumor growth and invasion ability.

Exosomal miR-548c-5p Regulates Colorectal Cancer Cell Growth and Invasion Through HIF1A/CDC42 Axis

Background

Mounting evidence has implicated that exosomes-delivered noncoding RNAs are key regulators in carcinogenesis. The effect of miR-548c-5p has been elucidated in some cancers. However, the role of exosomal miR-548c-5p in colorectal cancer (CRC) is not fully understood. We aim to explore the function and mechanism of exosome-delivered miR-548c-5p in CRC. The altering effect of exosome-derived miR-548c-5p on the prognosis of CRC patients is also investigated by estimating overall survival and disease-free survival.

Materials and Methods

The expression of miR-548c-5p in exosomes is determined by real-time PCR. The proliferation and invasion of CRC cells are estimated by MTT, transwell assay and scratch test. The targeted gene of miR-548c-5p is investigated by luciferase reporter assay, real-time PCR, Western blot and chromosome immunoprecipitation (CHIP) assay. CRC cells are transplanted subcutaneously in BALB/c nude mice to estimate their growth in vivo.

Results

MiR-548c-5p derived from CRC cell exosomes inhibits the proliferation and invasion of CRC cells in vitro. Exosomal miR-548c-5p can also prevent from colorectal carcinogenesis in nude mice in vivo. HIF1A is documented to be a target of miR-548c-5p, and HIF1A can targetedly regulate CDC42 in CRC cells. Exosomal miR-548c-5p affects CRC cell growth, migration and invasion via miR-548c-5p/HIF1A/CDC42 axis. In addition, exosomal miR-548c-5p can be a predictive factor for CRC prognosis.

Conclusion

Our study has suggested that exosomal miR-548c-5p can regulate CRC through HIF1A/CDC42 axis, which helps to understand CRC pathogenesis more clearly and identify novel therapeutic strategies for CRC patients.

Exosome: A Review of Its Classification, Isolation Techniques, Storage, Diagnostic and Targeted Therapy Applications

Exosomes are nano-sized small extracellular vesicles secreted by cells, carrying nucleic acids, proteins, lipids and other bioactive substances to play a role in the body's physiological and pathological processes. Compared to synthetic carriers such as liposomes and nanoparticles, the endogeneity and heterogeneity of exosomes give them extensive and unique advantages in the field of disease diagnosis and treatment. However, the storage stability, low yield, low purity, and weak targeting of exosomes limit its clinical application. For this reason, further exploration is needed to optimize the above problems and facilitate future functional studies of exosomes. In this paper, the origin, classification, preparation and characterization, storage stability and applications of exosome delivery system are summarized and discussed by searching a large number of literatures.

Exosomal noncoding RNAs in colorectal cancer

Colorectal cancer (CRC) is a commonly diagnosed malignancy with unsatisfactory survival outcomes. Recent studies indicate that noncoding RNAs (ncRNAs) can be selectively packaged into exosomes, the extracellular vesicles composed of a lipid bilayer, and delivered from donor to recipient cells, thus regulating the behavior of the recipient cells. Increasing evidence has demonstrated that exosomal ncRNAs in blood exhibit distinct expression patterns among CRC patients with or without metastasis, and healthy controls. Moreover, exosomal ncRNAs can participate in the regulation of tumor microenvironment, the establishment of pre-metastatic niches, and the induction of drug resistance via cell-to-cell communication. Intriguingly, exosomal ncRNAs have the potential to serve as biomarkers for diagnosis, prognostic prediction, and therapeutic response monitoring of patients with CRC. In this review, we summarize the emerging functions of exosomal ncRNAs during CRC development and also discuss their potential clinical application in patients with CRC.

Exosomal miR-638 Inhibits Hepatocellular Carcinoma Progression by Targeting SP1

Purpose

Exosomal microRNAs (miRNAs) play essential roles in the development of hepatocellular carcinoma (HCC). Nevertheless, the role and mechanism of exosomal miR-638 in HCC development remain largely unknown.

Methods

Exosomes were isolated and confirmed via transmission electron microscopy and western blot. The abundances of miR-638 and specificity protein 1 (SP1) were measured via quantitative reverse transcription polymerase chain reaction or western blot. Cell proliferation was investigated by Cell Counting Kit-8, colony formation assay, apoptosis, cell cycle distribution and related protein expression. Cell migration and invasion were detected via transwell assay and western blot. Co-culture experiment was performed to assess exosome transfer from HCC cells to endothelial cells. The target correlation between miR-638 and SP1 was analyzed via dual-luciferase reporter and RNA immunoprecipitation assays. The subcutaneous xenograft experiment was conducted to test the function of miR-638 in vivo.

Results

The miR-638 level declined in exosomes from serum or HCC cell medium. miR-638 overexpression repressed HCC cell proliferation by decreasing viability and colony formation and inducing apoptosis and cell cycle arrest at G1 phase, and decreased abilities of migration and invasion. Exosomal miR-638 from HCC cells could transfer to human umbilical vein endothelial cells (HUVECs) and suppress HUVEC proliferation, migration and invasion. SP1 was a target of miR-638 and overexpression of SP1 reversed the effect of miR-638 on HCC cells. Overexpression of miR-638 reduced xenograft tumor growth via decreasing SP1.

Conclusion

Exosomal miR-638 inhibited HCC tumorigenesis by targeting SP1. This study indicated the potential clinical implications of miR-638 in HCC.

Exosomal miR-106b serves as a novel marker for lung cancer and promotes cancer metastasis via targeting PTEN

As novel non-invasive tumor diagnostic biomarkers, exosomal bioactive miRNAs have received increasing attention. Herein, the aim of this study is to explore the clinical values and roles of exosomal miR106b in lung cancer. The exosomal miR-106b level was much higher in the serum of patients with lung cancer than that in healthy volunteers. Also, the exosomal miR-106b level in the lung cancer patient serum was associated with TNM stages and lymph node metastasis. Furthermore, exosomal miR-106b enhanced the migrated and invasive ability of lung cancer cells and increased the MMP-2 and MMP-9 expression. Mechanistically, exosomal miR-106b could target PTEN, and promote lung cancer cell migration and invasion. More importantly, PTEN overexpression reversed the effect of exosomal miR-106b on lung cancer cell migration and invasion. Taken together, these findings indicate that exosomal miR-106b may be a promising diagnostic biomarker and drug target for patients with lung cancer.

Exosomal miRNA: Small Molecules, Big Impact in Colorectal Cancer

Colorectal cancer (CRC) is one of the major causes of cancer-related deaths worldwide. Tumor microenvironment (TME) contains many cell types including stromal cells, immune cells, and endothelial cells. The TME modulation explains the heterogeneity of response to therapy observed in patients. In this context, exosomes are emerging as major contributors in cancer biology. Indeed, exosomes are implicated in tumor proliferation, angiogenesis, invasion, and premetastatic niche formation. They contain bioactive molecules such as proteins, lipids, and RNAs. More recently, many studies on exosomes have focused on miRNAs, small noncoding RNA molecules able to influence protein expression. In this review, we describe miRNAs transported by exosomes in the context of CRC and discuss their influence on TME and their potential as circulating biomarkers. This overview underlines emerging roles for exosomal miRNAs in cancer research for the near future.

A meta-analysis on the prognosis of exosomal miRNAs in all solid tumor patients

BACKGROUND

It has been reported that the encapsulated miRNAs from exosomes are potential biomarkers of tumors prognosis. Yet, the results are controversial, so it is obliged to do a meta-analysis to reach a definite conclusion.

MATERIALS AND METHODS

Studies were searched for published in PubMed, Embase, and Web of Science databases until April 20, 2018. A meta-analysis was conducted to appraise the role of exosomal miRNAs in prognosis of cancer patients.

RESULTS

The different exosomal miRNAs expression was remarkably related to overall survival (OS) (hazard ratio [HR] = 2.02, 95% confidence interval [CI]: 1.84-2.21) and disease-free survival (DFS) (HR = 2.43, 95% CI: 1.86-3.17) of cancer patients. High exosomal miR-21 expression was associated with poor OS (HR = 2.59; 95% CI: 1.71-3.90) and DFS (HR = 1.84; 95% CI: 1.37-2.47). High exosomal miR-451a expression was associated with poor OS (HR = 4.81; 95% CI: 2.33-9.93) and DFS (HR = 2.64; 95% CI: 1.62-4.31). High exosomal miR-1290 expression was associated with poor OS (HR = 1.73; 95% CI: 1.29-2.33). Low exosomal miR-638 expression was associated with poor OS (HR = 2.25; 95% CI: 1.46-3.46).

CONCLUSION

The expression levels of exosomal miRNAs, particularly miR-21, miR-451a, miR-1290, and miR-638 could strongly predict prognosis of solid tumor patients and might be a potential target for tumor treatment.

miR-548c-5p inhibits colorectal cancer cell proliferation by targeting PGK1

Accumulating studies have implicated that microRNAs (miRNAs) are involved in the pathogenesis of colorectal cancer (CRC). However, the role of miR-548c-5p, a novel identified miRNA in malignancies, in colorectal carcinogenesis remains largely unknown. The present study is aimed to investigate the effect and molecular mechanism of miR-548c-5p in CRC by a sequence of cellular experiments. miR-548c-5p was significantly downregulated, whereas phosphoglycerate kinase 1 (PGK1), a key enzyme for glycolysis, was obviously upregulated in peripheral blood mononuclear cells and cancer tissues from patients with CRC. Besides, miR-548c-5p and PGK1 were negatively associated with each other. The luciferase reporter assay revealed that PGK1 was a targeted gene of miR-548c-5p. Moreover, the proliferation and generation of inflammatory cytokines (TNF-α and IL-6) were significantly inhibited in miR-548c-5p-overexpressed SW480 CRC cells stimulated by lipopolysaccharide (LPS). Accordingly, miR-548c-5p may serve as a cancer suppressor in CRC by targeting PGK1.

Hypoxia-Regulated miRNAs in Human Mesenchymal Stem Cells: Exploring the Regulatory Effects in Ischemic Disorders

Human mesenchymal/stromal stem cells (hMSC) are the most promising cell source for adult cell therapies in regenerative medicine. Many clinical trials have reported the use of autologous transplantation of hMSCs in several disorders, but with limited results. To exert their potential, hMSCs could exhibit efficient homing and migration toward lesion sites among other effects, but the underlying process is not clear enough. To further increase the knowledge, we studied the co-regulation between hypoxia-regulated genes and miRNAs. To this end, we investigated the miRNA expression profile of healthy hMSCs in low oxygen/nutrient conditions to mimic ischemia and compared with cells of patients suffering from critical limb ischemia (CLI). miRNAs are small, highly conserved, non-coding RNAs, skilled in the control of the target’s expression level in a fine-tuned way. After analyzing the miRNOme in CLI-derived hMSC cells and healthy controls, and intersecting the results with the mRNA expression dataset under hypoxic conditions, we identified two miRNAs potentially relevant to the disease: miR-29b as a pathological marker of the disease and miR-638 as a therapeutic target. This study yielded a deeper understanding of stem cell biology and ischemic disorders, opening new potential treatments in the future.

miR-944 inhibits lung adenocarcinoma tumorigenesis by targeting STAT1 interaction

Lung adenocarcinoma (LAC) is a leading cause of cancer-associated mortalities, particularly in developed countries. The aberrant expression of microRNAs (miRNAs) has been proven to regulate numerous diseases in the past two decades. miRNAs have been identified in almost all human cancer types. In the present study, the role of miR-944 in LAC proliferation was examined. It was identified that miR-944 was downregulated in LAC tissues and cells, and miR-944 overexpression inhibited A549 and H1299 cell proliferation, as determined by the Cell Counting Kit-8 and colony formation assay. Signal transducer and activator of transcription 1 (STAT1) was upregulated in LAC tissues and cells. Kaplan-Meier analysis demonstrated that the 5-year overall survival in patients with high STAT1 levels was significantly reduced, compared with patients with negative and low STAT1 expression. STAT1 was the direct target of miR-944. Additionally, a miR-944 mimic inhibited A549 cell growth in vitro. Collectively, these data demonstrate that miR-944 serves a pivotal role in LAC tumor growth by targeting STAT1. The data obtained indicated that miR-944 may be a novel biomarker and could result in potential therapies for LAC.

Application of atomic force microscopy in cancer research

Atomic force microscopy (AFM) allows for nanometer-scale investigation of cells and molecules. Recent advances have enabled its application in cancer research and diagnosis. The physicochemical properties of live cells undergo changes when their physiological conditions are altered. These physicochemical properties can therefore reflect complex physiological processes occurring in cells. When cells are in the process of carcinogenesis and stimulated by external stimuli, their morphology, elasticity, and adhesion properties may change. AFM can perform surface imaging and ultrastructural observation of live cells with atomic resolution under near-physiological conditions, collecting force spectroscopy information which allows for the study of the mechanical properties of cells. For this reason, AFM has potential to be used as a tool for high resolution research into the ultrastructure and mechanical properties of tumor cells. This review describes the working principle, working mode, and technical points of atomic force microscopy, and reviews the applications and prospects of atomic force microscopy in cancer research.

hsa_circ_0000177-miR-638-FZD7-Wnt Signaling Cascade Contributes to the Malignant Behaviors in Glioma

As a new member of the noncoding RNA family, circular RNAs (circRNAs) have been demonstrated as critical regulators in various physiological and pathological processes, such as tumorigenesis. However, the role of circRNAs has not been well understood until now. In our study, we found that circRNA hsa_circ_0000177 was upregulated in glioma tissues and cell lines. Also, hsa_circ_0000177 overexpression was associated with poor prognosis in glioma patients. Through functional experiments, we found that hsa_circ_0000177 knockdown dramatically inhibited glioma cell proliferation and invasion in vitro. Consistently, hsa_circ_0000177 knockdown significantly repressed glioma growth in vivo. In terms of mechanism, we used bioinformatics analysis and identified hsa_circ_0000177 as a miR-638 sponge. We showed that miR-638 inhibition could restore the proliferation and invasion of glioma cells transfected with hsa_circ_0000177 small interfering RNA. Furthermore, we demonstrated that frizzled class receptor 7 (FZD7) was targeted by miR-638 and upregulated by hsa_circ_0000177. Through upregulating FZD7 expression, hsa_circ_0000177 activated Wnt signaling and facilitated glioma growth. Taken together, our study revealed a novel signaling pathway involved in glioma progression.

Exosomal miR-6803-5p as potential diagnostic and prognostic marker in colorectal cancer

Accumulating data have suggested exosome-delivered microRNAs (miRNAs) play critical role in carcinogenesis and cancer progression. However, little is known about the influence of exosomal miR-6803-5p on the development and prognosis of colorectal cancer (CRC). Levels of serum exosomal miR-6803-5p were determined by microarray analysis and verified by quantitative real-time PCR (qRT-PCR). Outcomes of overall survival (OS) and disease-free survival (DFS) of CRC patients were estimated by Kaplan-Meier analysis. We used cox regression analysis to investigate the association between exosomes-encapsulated miR-6803-5p and the clinicopathological factors of CRC patients. The exosomal miR-6803-5p was significantly increased in serum samples from patients with CRC in contrast to healthy controls. Significantly higher levels of serum exosomal miR-6803-5p were observed in CRC patients at later TNM stage or with lymph node metastasis as well as liver metastasis. Patients with elevated levels of serum exosomal miR-6803-5p had much poorer OS and DFS. Cox regression analysis revealed high levels of exosomal miR-6803-5p was associated with poor prognosis in CRC independent of other confounding factors. Thus, exosomal miR-6803-5p is a potential diagnostic and prognostic biomarker for patients with CRC.