Role of miR-191/425 cluster in tumorigenesis and diagnosis of gastric cancer

Free circulating versus extracellular vesicle-associated microRNA expression in canine T-cell lymphoma

Introduction

Canine lymphoma (cL) is one of the most frequent cancers in dogs. The T-cell lymphoma (TcL) is not the most common phenotype but presents an aggressive behavior. MicroRNAs (miRNAs), are small, single-stranded, non-coding RNA molecules which can circulate freely in blood or be associated with extracellular vesicles (EVs). The dysregulation of certain miRNAs has been identified in numerous types of human cancers and they have been largely investigated as possible tumors biomarkers in human medicine, while research in veterinary oncology is still scarce. The aim of this study was to compare the expression patterns of free circulating and EV-associated miRNAs in dogs with T-cell lymhoma (TcL) and healthy dogs.

Methods

Eight dogs with TcL were selected as the lymphoma group (LG) and eight dogs were included as controls (Ctrl). Plasma samples were collected at the time of the diagnosis and EVs isolated with ultracentrifugation. miRNAs were extracted from both the circulating EVs and the plasma supernatant, obtaining EV-associated and free-miRNAs. Quantitative real-time PCR was performed to analyze the expression of 88 target miRNAs.

Results

Ten and seven differentially expressed miRNAs between LG and Ctrl were detected in EV-associated and free-miRNAs, respectively. Among EV-associated and free-miRNAs, only has-miR-222-3p was overexpressed in both conditions.

Discussion

All the differentially expressed miRNAs detected in this study, have been already described as dysregulated in other human or canine cancers. The EV-associated miRNAs, which appear to be more stable and better conserved than free-miRNAs, could be investigated in further larger studies to better assess their use as possible biomarkers for TcL.

Multi-step regulation of microRNA expression and secretion into small extracellular vesicles by insulin

Tissues release microRNAs (miRNAs) in small extracellular vesicles (sEVs) including exosomes, which can regulate gene expression in distal cells, thus acting as modulators of local and systemic metabolism. Here, we show that insulin regulates miRNA secretion into sEVs from 3T3-L1 adipocytes and that this process is differentially regulated from cellular expression. Thus, of the 53 miRNAs upregulated and 66 miRNAs downregulated by insulin in 3T3-L1 sEVs, only 12 were regulated in parallel in cells. Insulin regulated this process in part by phosphorylating hnRNPA1, causing it to bind to AU-rich motifs in miRNAs, mediating their secretion into sEVs. Importantly, 43% of insulin-regulated sEV-miRNAs are implicated in obesity and insulin resistance. These include let-7 and miR-103, which we show regulate insulin signaling in AML12 hepatocytes. Together, these findings demonstrate an important layer to insulin's regulation of adipose biology and provide a mechanism of tissue crosstalk in obesity and other hyperinsulinemic states.

Non-Coding RNA as Biomarkers and Their Role in the Pathogenesis of Gastric Cancer-A Narrative Review

Non-coding RNAs (ncRNAs) represent a broad family of molecules that regulate gene expression, including microRNAs, long non-coding RNAs and circular RNAs, amongst others. Dysregulated expression of ncRNAs alters gene expression, which is implicated in the pathogenesis of several malignancies and inflammatory diseases. Gastric cancer is the fifth most frequently diagnosed cancer and the fourth most common cause of cancer-related death. Studies have found that altered expression of ncRNAs may contribute to tumourigenesis through regulating proliferation, apoptosis, drug resistance and metastasis. This review describes the potential use of ncRNAs as diagnostic and prognostic biomarkers. Moreover, we discuss the involvement of ncRNAs in the pathogenesis of gastric cancer, including their interactions with the members of major signalling pathways.

MicroRNA-191 regulates oral squamous cell carcinoma cells growth by targeting PLCD1 via the Wnt/β-catenin signaling pathway

BACKGROUND

Studies have shown that microRNA-191 (miR-191) is involved in the development and progression of a variety of tumors. However, the function and mechanism of miR-191 in oral squamous cell carcinoma (OSCC) have not been clarified.

METHODS

The expression level of miR-191 in tumor tissues of patients with primary OSCC and OSCC cell lines were detected using real-time quantitative polymerase chain reaction (RT-qPCR) and western blot. OSCC cells were treated with miR-191 enhancers and inhibitors to investigate the effects of elevated or decreased miR-191 expression on OSCC cells proliferation, migration, cell cycle, and tumorigenesis. The target gene of miR-191 in OSCC cells were analyzed by dual-Luciferase assay, and the downstream signaling pathway of the target genes was detected using western blot assay.

RESULTS

The expression of miR-191 was significantly upregulated in OSCC tissues and cell lines. Upregulation of miR-191 promoted proliferation, migration, invasion, and cell cycle progression of OSCC cells, as well as tumor growth in nude mice. Meanwhile, reduced expression of miR-191 inhibited these processes. Phospholipase C delta1 (PLCD1) expression was significantly downregulated, and negatively correlated with the expression of miR-191 in OSCC tissues. Dual-Luciferase assays showed that miR-191-5p could bind to PLCD1 mRNA and regulate PLCD1 protein expression. Western blot assay showed that the miR-191 regulated the expression of β-catenin and its downstream gene through targeting PLCD1.

CONCLUSION

MicroRNA-191 regulates oral squamous cell carcinoma cells growth by targeting PLCD1 via the Wnt/β-catenin signaling pathway. Thus, miR-191 may serve as a potential target for the treatment of OSCC.

Effect of Mir-4270 Inhibitor and Mimic on Viability and Stemness in Gastric Cancer Stem-Like Cells Derived from MKN-45 Cell Line

Background

MicroRNAs (miRNAs) are significant regulatory factors in stem cell proliferation, and change in miRNA expression influences the cancer stem cell viability and gene expression. Herein, we evaluated the effect of the hsa-miR-4270 inhibitor and its mimic on the expression of stem cell markers in gastric cancer (GC) stem-like cells.

Methods

GC stem-like cells were isolated from the MKN-45 cell line by a non-adherent surface system. The cells were confirmed by differentiation assays using dexamethasone and insulin as adipogenesis-inducing agents and also Staurosporine as a neural-inducing agent. Isolated GC stem-like cells were treated with different concentrations (0, 15, 20, 25, 30, 40, 50, and 60 nM) of hsa-miR-4270 inhibitor and its mimic. The quantity of cell viability was determined by trypan blue method. Transcription of the stem cell marker genes, including CD44, OCT3/4, SOX2, Nanog, and KLF4, was evaluated by real-time RT-PCR.

Results

The results showed that GC stem-like cells were differentiated into both adipose cells using dexamethasone and insulin and neural cells by Staurosporine. Treatment of GC stem-like cells with hsa-miR-4270 inhibitor decreased cell viability and downregulated OCT3/4, CD44, and Nanog to 86%, 79%, and 91% respectively. Also, SOX2 and KLF4 were overexpressed to 8.1- and 1.94-folds, respectively. However, hsa-miR-4270 mimic had opposite effects on the cell viability and gene expression of the stem cell markers.

Conclusion

The effect of hsa-miR-4270 inhibitor and its mimic on the expression of the stem cell markers in GCSCs indicated that hsa-miR-4270 stimulates the stemness property of GCSCs, likely through stimulating the development of gastric stem cells.

Diverse Functions of MiR-425 in Human Cancer

miRNAs are a type of small endogenous noncoding RNA composed of 20-22 nucleotides that can regulate gene expression by targeting the 3' untranslated region of mRNA. Many investigations have discovered that miRNAs have a role in the development and progression of human cancer. Several aspects of tumor development are affected by miR-425, including growth, apoptosis, invasion, migration, epithelial-mesenchymal transition, and drug resistance. In this article, we discuss the properties and research development of miR-425, focusing on the regulation and function of miR-425 in various cancers. Furthermore, we discuss the clinical implications of miR-425. This review may broaden our horizon for better understanding the role of miR-425 as biomarkers and therapeutic targets in human cancer.

MiR-191-5p inhibits KLF6 to promote epithelial-mesenchymal transition in breast cancer

BACKGROUND

MicroRNAs (miRNAs) exert certain functions in the development of several cancers and can be a potential hallmark for cancer diagnosis and prognosis. MiR-191-5p has been proven to have high expression in breast cancer (BC), while its biological role and potential regulatory mechanisms in BC remain an open issue.

OBJECTIVE

Bioinformatics was utilized to assay miR-191-5p level in BC tissues and predict its downstream target gene as well as the enriched signaling pathways of the target gene.

METHODS

qRT-PCR was carried out to assay miR-191-5p and KLF6 levels in BC cells as well as miR-191-5p level in blood-derived exosomes from BC patients. Western blot was to examine the expression of proteins linked with cell adhesion, epithelial-mesenchymal transition (EMT), and exosome markers. A dual luciferase reporter assay was utilized to verify the interaction between miR-191-5p and KLF6. Abilities of cell phenotypes of BC cells were detected by CCK8, Transwell, and cell adhesion assay, separately.

RESULTS

Upregulated miR-191-5p expression and downregulated KLF6 expression were observed in BC cells. There was a targeting relationship between miR-191-5p and KLF6. MiR-191-5p negatively regulated KLF6 to promote EMT and malignant progression of BC cells. Additionally, we described a dramatically high level of miR-191-5p in the blood exosomes of BC patients.

CONCLUSION

MiR-191-5p advances the EMT of BC by targeting KLF6, indicating that miR-191-5p and KLF6 may be new biomarkers for BC.

MiR-873-5p targets THUMPD1 to inhibit gastric cancer cell behavior and chemoresistance

Background

Gastric cancer is one of the most common gastrointestinal tumors. Evidence has pointed to the fact that miRNAs play critical roles in the occurrence, development, and metastasis of gastric cancer by regulating cell proliferation, differentiation, apoptosis, and invasion.

Methods

In this study, first the relationship of miR-873-5p level and tissues types/LN(+/-)/metastasis(+/-)/tumor size was analysis, respectively. Second, the CCK8 and Transwell assay was used to determine the proliferation, invasion and migration of GC cells transfected with overexpression-/low expression-miR-873-5p. Third, the cell viability were analysis in the GC cells transfected with overexpression-/low expression-miR-873-5p treatment with different chemotherapy drugs. Fourth, the target gene of miR-873-5p was predicted using bioinformation methods. Fifth, the relationship of miR-873-5p with target gene-THUMPD1 were explored by using Wb and luciferase activity assay, et al.

Results

We confirmed that miR-873-5p was negatively correlated with GC including tumor size, LN metastasis, distant metastasis. The miR-873-5p enhanced the sensitivity of Doxorubicin/Fluorouracil and cisplatin. The THUMPD1 was the target gene of miR-873-5p. Moreover, miR-873-5p could target the THUMPD1 axis so as to inhibit gastric cancer cell behavior as well as chemoresistance.

Conclusions

MiR-873-5p plays a role in regulating cell behavior as well as regulating chemoresistance in gastric cancer. In addition, THUMPD1, as a downstream molecule of miR-873-5p, plays an important role in the cell behavior and chemoresistance of gastric cancer. The research first confirmed that miR-873-5p could inhibit gastric cancer cell behavior and chemoresistance by targeting the THUMPD1.

6 Circulating miRNAs can be used as Non-invasive Biomarkers for the Detection of Cervical Lesions

Background: Cervical cancer is the most common malignant tumor in the female reproductive system, while the efficacy of routine screening strategy is unsatisfied. New molecular tests need to be developed. miRNAs participate in many pathologic processes, and circulating miRNAs are promising non-invasive biomarkers in tumors.

Objectives: This study aimed to identify the circulating miRNAs associated with both cervical cancer and cervical intraepithelial neoplasia (CIN), and establish a non-invasive classifier for cervical lesions using circulating miRNAs.

Methods: This study consisted of 5 steps: miRNAs screening, miRNAs validation, classifier establishment, independent validation and in silico analyses. Three cohorts were included in our study: In screening stage, 24 samples including 14 cases and 10 controls were retrieved; In validation stage, 380 samples including 200 cases and 180 controls were recruited; In independent validation stage, 47 samples comprising 26 cases and 21 controls were included. miRNAs were quantified by RT-qPCR. A classifier was built with random forest algorithm using validation samples and selected miRNAs, which were then validated in an independent cohort. To explore the function of selected miRNAs, in silico analyses were performed. Target genes of selected miRNAs were predicted by the overlap of three online tools. Enrichment analyses were executed with predicted target genes. Differential analysis of target genes was carried out with open access expression assay datasets of cervical tissues.

Results: 6 miRNAs (hsa-miR-26b-5p, hsa-miR-146b-5p, hsa-miR-191-5p, hsa-miR-484, hsa-miR-574-3p, hsa-miR-625-3p) were screened out from 754 miRNAs. They were associated with cervical lesions and were selected to establish a classifier. The accuracy of the classifier were 0.7218 (0.7117, 0.7319) in validation samples, which was 0.7021 in the independent cohort. 958 target genes were predicted and enriched in 23 pathways (MAPK, human papillomavirus infection and Wnt signaling pathway, etc.). 55 genes were identified as the most likely target genes by differential analysis.

Conclusion: The 6 circulating miRNAs were related to cervical lesions and could serve as non-invasive biomarkers.

Small RNAs as biomarkers to differentiate benign and malign prostate diseases: An alternative for transrectal punch biopsy of the prostate?

Prostate cancer (PCa) is the most common cancer and the third most frequent cause of male cancer death in Germany. MicroRNAs (miRNA) appear to be involved in the development and progression of PCa. A diagnostic differentiation from benign prostate hyperplasia (BPH) is often only possible through transrectal punch biopsy. This procedure is described as painful and carries risks. It was investigated whether urinary miRNAs can be used as biomarkers to differentiate the prostate diseases above. Therefore urine samples from urological patients with BPH (25) or PCa (28) were analysed using Next-Generation Sequencing to detect the expression profile of total and exosomal miRNA/piRNA.

79 miRNAs and 5 piwi-interacting RNAs (piRNAs) were significantly differentially expressed (adjusted p-value < 0.05 and log2-Fc > 1 or < -1). Of these, 6 miRNAs and 2 piRNAs could be statistically validated (AUC on test cohort > = 0.7). In addition, machine-learning algorithms were used to identify a panel of 22 additional miRNAs, whose interaction makes it possible to differentiate the groups as well. There are promising individual candidates for potential use as biomarkers in prostate cancer. The innovative approach of applying machine learning methods to this kind of data could lead to further small RNAs coming into scientific focus, which have so far been neglected.

MicroRNA-425 induces apoptosis and suppresses migration and invasion of human cervical cancer cells by targeting RAB2B

Dysregulation of microRNA-425 (miR-425) has been reported in several human cancers. However, the role of miR-425 in human cervical cancer via modulation of RAB2B expression is still unclear. This study was therefore designed to examine the expression and decipher the role of miR-425 in cervical cancer. The qRT-PCR was used for expression analysis. MTT and EdU assays were used for the determination of cell viability and proliferation, respectively. Annexin V/PI staining was used to detect apoptosis. Wound healing and transwell assays were used to monitor cell migration and invasion. Western blotting was used for protein expression analysis. The in vivo study was performed in xenografted mice model. The results of the present study revealed miR-425 to be significantly (P = 0.032) down-regulated in cervical cancer tissues and cell lines. Additionally, low expression of miR-425 was associated with significantly (P = 0.035) lower survival rate of the cervical cancer patients. Overexpression of miR-425 resulted in significant (P = 0.024) decline of cervical cancer cell proliferation via induction of apoptosis. The induction of apoptosis was associated with up-regulation of Bax and down-regulation of Bcl-2. Besides, the migration and invasion of cancer cells significantly (P < 0.01) decreased under miR-425 overexpression. Additionally, miR-425 could inhibit the growth of xenografted tumors in vivo. In silico analysis and dual luciferase assay revealed RAB2B as the direct target of miR-425 in cervical cancer. RAB2B was found to be significantly (P < 0.05) up-regulated in cervical cancer tissues and cell lines and miR-425 overexpression suppressed the expression of RAB2B. Additionally, silencing of RAB2B could suppress the growth of cervical cancer cells but its overexpression could rescue the tumor-suppressive effects of miR-425. Taken together, the results revealed the tumor-suppressive roe of miR-425 and point towards its therapeutic potential in the management of cervical cancer.

miR-155, miR-191, and miR-494 as diagnostic biomarkers for oral squamous cell carcinoma and the effects of Avastin on these biomarkers

Objectives

Oral squamous cell carcinoma (OSCC) is one of the most common types of head and neck cancer. MicroRNAs, as new biomarkers, are recommended for diagnosis and treatment of different types of cancers. Bevacizumab, sold under the trade name Avastin, is a humanized whole monoclonal antibody that targets and blocks VEGF-A (vascular endothelial growth factor A; angiogenesis) and oncogenic signaling pathways.

Materials and Methods

This study comprised 50 cases suffering from OSCC and 50 healthy participants. Peripheral blood samples were collected in glass test tubes, and RNA extraction was started immediately. Expression levels of miR-155, miR-191, and miR-494 biomarkers in the peripheral blood of OSCC-affected individuals and healthy volunteers in vivo were evaluated using real-time PCR. The influence of Avastin on the expression levels of the aforementioned biomarkers in vitro and in the HN5 cell line was also investigated.

Results

Expression levels of miR-155, miR-191, and miR-494 in the peripheral blood of individuals affected by OSCC were higher than in those who were healthy. Moreover, Avastin at a concentration of 400 µM caused a decrease in the expression levels of the three biomarkers and a 1.5-fold, 3.5-fold, and 4-fold increase in apoptosis in the test samples compared to the controls in the HN5 cell line after 24, 48, and 72 hours, respectively.

Conclusion

The findings of this study demonstrate that overexpression of miR-155, miR-191, and miR-494 is associated with OSCC, and Avastin is able to regulate and downregulate the expression of those biomarkers and increase apoptosis in cancerous cells in the HN5 cell line

Hsa-miR-425-5p promotes tumor growth and metastasis by activating the CTNND1-mediated β-catenin pathway and EMT in colorectal cancer

Colorectal cancer (CRC) is a common malignancy with high mortality. However, the roles of miR-425-5p and its underlying mechanism in CRC remain unknown. Here, RT-qPCR confirmed that miR-425-5p expression was increased by miR-425-5p mimic in SW480 cells and decreased by miR-425-5p inhibitor in LOVO cells. CCK-8, flow cytometry, wound healing and transwell assays revealed that the increased miR-425-5p promoted cell viability, cell cycle entry, migration and invasion in CRC. Besides, miR-425-5p overexpression induced epithelial-mesenchymal transition (EMT) with upregulation of Fibronectin, N-cadherin, Vimentin, and downregulation of E-cadherin. Moreover, miR-425-5p overexpression induced c-myc, Cyclin D1 and MMP7 levels, and promoted β-catenin translocation to the nucleus. Knockdown of miR-425-5p exerted opposite effects. Luciferase reporter assay indicated that miR-425-5p directly targeted CTNND1. Overexpression of miR-425-5p repressed CTNND1 expression at mRNA and protein levels. Silencing of CTNND1 had the inhibitory effect of miR-425-5p inhibitor on cell proliferation, migration, invasion, EMT, and the activation of β-catenin signaling pathway. Furthermore, miR-425-5p promoted tumor growth and metastasis in vivo. In conclusion, miR-425-5p may promote tumorigenesis and metastasis through activating CTNND1-mediated β-catenin pathway, which may provide therapeutic targets for human CRC.

MicroRNA-425 inhibits proliferation of chronic lymphocytic leukaemia cells through regulation of the Bruton's tyrosine kinase/phospholipase Cγ2 signalling pathway

The present study aimed to investigate the effects of microRNA (miR)-425 on the proliferation of chronic lymphocytic leukaemia (CLL) cells and the possible underlying mechanisms. The expression of miR-425 was determined in the B lymphocytes of CLL patients and in normal B lymphocytes by reverse transcription-quantitative polymerase chain reaction (RT-qPCR). In addition, MEC-1 cells transfected with miR-425 negative control (NC) or miR-425 mimic were examined. The cell proliferation of different groups was evaluated using an MTT assay, and cell cycle distribution was evaluated using flow cytometry analysis. A dual-luciferase reporter assay was used to verify whether Bruton's tyrosine kinase (BTK) was a target of miR-425. Furthermore, the expression levels of BTK, phospholipase Cγ2 (PLCγ2), Ki-67 and proliferating cell nuclear antigen (PCNA) were determined by RT-qPCR and western blotting. The results revealed that the expression of miR-425 was significantly downregulated in B lymphocytes obtained from CLL patients as compared with that in normal B lymphocytes. When cells were transfected with miR-425 mimic, the proliferation of MEC-1 cells was significantly inhibited at 24, 48 and 72 h compared with the proliferation of control cells. Additionally, the ratio of G0/G1 cells was significantly increased and the ratio of G2/M cells was significantly decreased in miR-425-overexpressing cells compared with that in control cells. The luciferase reporter assay revealed that miR-425 binds to the 3'-untranslated region of BTK mRNA. Finally, BTK, PLCγ2, Ki-67 and PCNA expression was significantly inhibited at the mRNA and protein level in cells where miR-425 was upregulated. In conclusion, miR-425 inhibits the proliferation of MEC-1 cells, potentially by inhibiting BTK/PLCγ2 signalling, and Ki-67 and PCNA expression levels. These results provide a deeper insight for understanding the development of CLL and suggest a potential novel target for the treatment of CLL patients.

Serum miR-191 and miR-425 as Diagnostic and Prognostic Markers of Advanced Gastric Cancer Can Predict the Sensitivity of FOLFOX Chemotherapy Regimen

Purpose

miR-191 and miR-425 have been proved to be highly expressed in gastric carcinoma (GC). However, little research has been done on their clinical value in serum of patients with advanced GC. In addition, it is not clear whether they can be used as markers for the response and prognosis of GC patients treated with oxaliplatin combined with 5-fluorouracil and FOLFOX chemotherapy.

Patients and Methods

A total of 230 patients with advanced GC admitted to our hospital were selected as the study objects, all of whom received FOLFOX chemotherapy regimen. Another 100 cases of healthy subjects were included. QRT-PCR was employed to detect the serum expression of miR-191 and miR-425 in patients.

Results

Compared with the healthy subjects, the serum expressions of miR-191 and miR-425 in GC patients were significantly upregulated, which were correlated with differentiation degree and TNM staging, respectively. According to the ROC curve, the AUC of miR-191 and miR-425 for GC diagnosis was 0.937 and 0.901, respectively, while the AUC for differentiation degree diagnosis was 0.854 and 0.822, and that for TNM staging diagnosis was 0.860 and 0.829, respectively. The predictive AUC of miR-191 and miR-425 for chemosensitivity was 0.868 and 0.835, respectively, with a combined predictive AUC of 0.935. Low differentiation degree, high TNM staging, high miR-191 and high miR-425 expressions were independent risk factors for chemotherapy insensitivity. Differentiation degree, TNM staging, chemotherapy effect, miR-191 and miR-425 were independent influencing factors for the prognosis of GC patients.

Conclusion

Up-regulated expression of miR-191 and miR-425 in the serum of patients with advanced GC are effective biomarkers for the diagnosis, chemotherapy and prognosis evaluation of GC.

Bioinformatic analyses of microRNA-targeted genes and microarray-identified genes correlated with Barrett's esophagus

Barrett's esophagus (BE) is defined as a metaplasia condition in the distal esophagus, in which the native squamous epithelium lining is replaced by a columnar epithelium with or without intestinal metaplasia. It is commonly accepted that BE is a precancerous lesion for esophageal adenocarcinoma. The aim of this study was to investigate the aberrant microRNAs (miRNAs) and differentially expressed genes (DEGs) associated with BE based on online microarray datasets. One miRNA and five gene expression profiling datasets were retrieved from the Gene Expression Omnibus Database. Aberrant microRNAs and DEGs were obtained using R/Bioconductor statistical analysis language and software. 23 dysregulated miRNAs and 632 DEGs demonstrating consistent expression tendencies in the five gene microarrays were identified in BE. Moreover, 1962 target genes of aberrant miRNAs were predicted using three bioinformatic tools, namely TargetScan, RNA22-HSA and miRDB. Ultimately, 93 target DEGs were obtained, after which functional annotation was performed on DAVID Bioinformatics Resources. Among Gene Ontology (GO) biological processes, digestive tract development and epithelial cell differentiation have demonstrated significant associations with BE pathogenesis. In addition, analysis of the KEGG pathways has revealed associations with cancer. To enable further study, one miRNA-target DEGs regulatory network was constructed using Cytoscape. 6 target DEGs demonstrated higher-degree distributions in the network, and ROC analysis indicated that FNDC3B may be the best potential biomarker for BE diagnosis. The data presented herein may provide new perspectives for exploring BE pathogenesis and may offer hits with regard to potential biomarkers in BE diagnosis, prediction and therapeutic evaluation.

Cluster miRNAs and cancer: Diagnostic, prognostic and therapeutic opportunities

MiRNAs are class of noncoding RNA important for gene expression regulation in many plants, animals and viruses. MiRNA clusters contain a set of two or more miRNA encoding genes, transcribed together as polycistronic miRNAs. Currently, there are approximately 159 miRNA clusters reported in the human genome consisting of miRNAs ranging from two or more miRNA genes. A large proportion of clustered miRNAs resides in and around the fragile sites or cancer associated genomic hotspots and plays an important role in carcinogenesis. Altered expression of miRNA cluster can be pro-tumorigenic or anti-tumorigenic and can be targeted for clinical management of cancer. Over the past few years, manipulation of miRNA clusters expression is attempted for experimental purpose as well as for diagnostic, prognostic and therapeutic applications in cancer. Re-expression of miRNAs by epigenetic therapy, genome editing such as clustered regulatory interspaced short palindromic repeats (CRISPR) and miRNA mowers showed promising results in cancer therapy. In this review, we focused on the potential of miRNA clusters as a biomarker for diagnosis, prognosis, targeted therapy as well as strategies for modulating their expression in a therapeutic context. This article is categorized under: Regulatory RNAs/RNAi/Riboswitches > Regulatory RNAs RNA Processing > Processing of Small RNAs RNA in Disease and Development > RNA in Disease Regulatory RNAs/RNAi/Riboswitches > Biogenesis of Effector Small RNAs.

MicroRNA-191 promotes hepatocellular carcinoma cell proliferation by has_circ_0000204/miR-191/KLF6 axis

OBJECTIVES

MicroRNAs are powerful regulators in hepatocellular carcinoma (HCC) tumorigenesis. MicoRNA-191 (miR-191) has been reported to play an important role in HCC, However, the regulatory mechanism is still unclear. In this study, we investigated the role of miR-191 in HCC and studied its underlying mechanisms of action.

MATERIALS AND METHODS

The expression of miR-191 in HCC tissues was determined by quantitative real-time PCR (qRT-PCR). The role of miR-191 in HCC cells was examined by using both in vitro and in vivo assays. Downstream targets of miR-191 were determined by qRT-PCR and Western blot analysis. Dual-luciferase assays were performed to validate the interaction between miR-191 and its targets.

RESULTS

The expression of miR-191 was significantly higher in HCC patients and a higher miR-191 expression predicted poorer prognosis. Analysis of The Cancer Genome Atlas data sets suggested that miR-191 positively correlated with cell cycle progression. Gain and loss of function assays showed that miR-191 promoted cell cycle progression and proliferation. Luciferase reporter assay showed that miR-191 directly targeted the 3'-untranslated region of KLF6 mRNA. Furthermore, circular RNA has_circ_0000204 could sponge with miR-191, resulting in inactivation of miR-191.

CONCLUSIONS

Our study sheds light on the novel underlying mechanism of miR-191 in HCC, which may accelerate the development of cancer therapy.

Identification of a transcription factor-microRNA network in esophageal adenocarcinoma through bioinformatics analysis and validation through qRT-PCR

Purpose: The rapidly rising incidence of esophageal adenocarcinoma (EAC), which is usually diagnosed late with a poor prognosis, has become a growing problem. This study investigated the potential transcription factor (TF)-related molecular mechanisms of EAC by using bioinformatics analysis and qRT-PCR validation.

Methods: Expression profile datasets for mRNAs (GSE92396, GSE13898, GSE26886 and GSE1420) and miRNAs (GSE16456) were downloaded from the GEO database. Overlapping differentially expressed genes (DEGs) and differentially expressed miRNAs (DEMs) were identified through integrative analysis. Then, a TF-miRNA-mRNA network was constructed based on bioinformatics data from the TRRUST, TRED and miRTarBase database. Furthermore, overall survival analysis for the mRNAs and miRNAs in the TF-miRNA-mRNA network was performed with data from TCGA, and qRT-PCR was used to validate the results.

Results: A total of 294 overlapping DEGs were identified in EAC tissues compared to normal tissues, including 181 downregulated and 113 upregulated genes. Then, 16 TFs that could target the DEGs and were related to cancer were predicted based on public databases, and 41 DEGs that could be targeted were identified as key genes. Additionally, 12 DEMs were predicted through miRTarBase to be associated with the key genes, and TP53-(miR-125b)-ID2 and JUN-(miR-30a)-IL1A from the TF-miRNA-mRNA network were identified to potentially play significant roles in EAC. Furthermore, CCL20, IL1A, ABCC3, hsa-miR-23b, and hsa-miR-191, which are involved in the TF-miRNA-mRNA network, were found to be significantly associated with patient survival in EAC. Finally, the expression of a miRNA-mRNA pair (hsa-miR-30a-5p and IL1A) was revealed to be correlated with prognosis.

Conclusion: In this study, a TF-miRNA-mRNA network was constructed to analyze the potential molecular mechanisms of EAC. Key genes and miRNAs associated with patient survival were identified, which may reveal promising approaches for EAC diagnosis and therapy.

Elevation of miR-191-5p level and its potential signaling pathways in hepatocellular carcinoma: a study validated by microarray and in-house qRT-PCR with 1,291 clinical samples

BACKGROUND

The miR-191-5p expression has been reported to increase in hepatocellular carcinoma (HCC), but its clinical value and exact role remain to be further clarified. Thus, a comprehensive analysis was performed in the current study to explore the underlying function of miR-191-5p in HCC.

METHODS

HCC-related expression data were collected to conduct a thorough analysis to determine the miR-191-5p expression and its clinical significance in HCC, including microarray data from the Gene Expression Omnibus and ArrayExpress database as well as quantitative real-time polymerase chain reaction (qRT-PCR) data of 178 matched clinical samples. The underlying relationship between miR-191-5p and HCC was also explored on the basis of a series of bioinformatics analyses.

RESULTS

The overall pooled meta-analysis showed an overexpression of miR-191-5p in the HCC samples (SMD=0.400, 95% CI=0.139-0.663, P=0.003), consistent with the detected result of the clinical HCC samples through the qRT-PCR analysis. Higher miR-191-5p levels were correlated with advanced TNM stages (III and IV), higher pathological grades, and metastasis. Functionally, 64 potential target genes were acquired for further mechanism analysis. Two pathways (p75 neurotrophin receptor and liver kinase B1-mediated signaling pathways), which were likely modulated by miR-191-5p, were regarded to be linked to the deterioration of HCC. Early growth response 1 and UBE2D3 were identified as the most likely targets for miR-191-5p in HCC and were commonly implied in the top enriched pathways and protein-protein network.

CONCLUSIONS

In summary, miR-191-5p may function as a tumor promoter miRNA of HCC, and the miR-191-5p inhibitor may contribute to the targeted HCC treatment in the future.

Hypoxia-induced miR-191-C/EBPβ signaling regulates cell proliferation and apoptosis of fibroblast-like synoviocytes from patients with rheumatoid arthritis

BACKGROUND

Hypoxia plays an important role in the proliferation of rheumatoid arthritis fibroblast-like synoviocytes (RA-FLS), leading to pathology of RA. This study was conducted to evaluate hypoxia-induced microRNAs (hypoxamiR) in RA-FLS and its role in the function of RA-FLS.

METHODS

RA-FLS were cultured under normoxia (21% O₂) or hypoxia (3% O₂) condition, followed by a microRNA (miRNA) array analysis. The upregulation of miR-191 by hypoxia was confirmed in RA-FLS and FLS from osteoarthritis (OA) patients by quantitative real-time polymerase chain reaction (RT-PCR). Transfection of miR-191 mimic and inhibitor was used to investigate the function of miR-191 in RA-FLS. The functional targets of miR-191 were predicted by bioinfomatics and then validated by reporter gene assay.

RESULTS

A subset of miRNAs was identified to be induced by hypoxia including miR-191. The upregulation of miR-191 was found to be specific in hypoxic RA-FLS, compared to hypoxic OA-FLS. We observed that miR-191 in RA-FLS increased cellular proliferation via promoting G₁/S transition of the cell cycle and suppressed cell apoptosis induced by cell starvation. Bioinformatical analysis and experimental assays identified CCAAT/enhancer binding protein β (C/EBPβ) as a target gene of miR-191 in RA-FLS. Enforced expression of C/EBPβ rescued the cellular phenotypes induced by miR-191. In addition, an inverse correlation between the C/EBPβ level and hypoxia stimulation was found in RA-FLS, and overexpression of C/EBPβ could partly rescue the hypoxia-induced cell proliferation.

CONCLUSION

We demonstrated the miR-191-C/EBPβ signaling pathway mediating the hypoxia-induced cell proliferation in RA.

Identification of diagnostic utility and molecular mechanisms of circulating miR-551b-5p in gastric cancer

BACKGROUND

Gastric cancer (GC) is one of the most common cancers globally leading to 850,000 deaths each year. GC patients are often diagnosed at advanced stages which results in poor prognosis. This study aimed to identify a novel circulating miRNA as the diagnostic biomarker of GC and further explore its regulatory mechanisms in GC.

MATERIALS AND METHODS

First, the candidate serum miRNA was selected after analysis of microarray data. Then, the levels of candidate miRNA in the serum of GC patients were validated in an independent cohort. The diagnostic utility of miRNA was evaluated by using receiver operating characteristic curve (ROC) analysis. The functional and pathways enrichment analysis of targets of candidate miRNA were explored by online tool DAVID.

RESULTS

After comprehensive analysis of Gene Expression Omnibus (GEO) dataset, miR-551b-5p was selected as candidate due to its highest differential fold-change. Another independent cohort showed that serum miR-551b-5p could differentiate GC patients from healthy controls (HCs) with area under the curve (AUC) of 0.84 (95%CI: 0.75-0.93). The functional and pathways enrichment analysis revealed that targets of miR-551b-5p mainly located in cytoplasm and significantly associated with regulation of ubiquitin-dependent protein catabolic process, cell division, and mRNA stability.

CONCLUSIONS

Circulating miR-551b-5p was a novel promising biomarker for the detection of GC and exploration of the molecular mechanisms of miR-551b-5p is useful to search for new therapeutic strategies of GC.

The diagnostic value of circulating microRNAs as a biomarker for gastric cancer: A meta‑analysis

Recently, cancer research microRNA studies have drawn great attention. However, the results of these studies have been inconsistent and variable regarding the availability of circulating miRNAs in gastric cancer (GC) diagnosis. Thus, results should be interpreted cautiously. The purpose of the present study was to assess the diagnostic performance of circulating miRNAs in GC diagnosis. We conducted a systematic and comprehensive approach for the inclusion of studies. The sensitivity, specificity, and diagnostic odds ratio were pooled with random effects models, and a summary of receiver operator characteristic (SROC) curves were plotted. The potential heterogeneity was assessed with Q test and I2 statistics. Subgroup analyses and meta‑regressions further investigated the sources of heterogeneity. A total of 77 studies from 48 articles were eligible for the meta‑analysis. The results revealed a sensitivity of 0.76, a specificity of 0.81, and an AUC of 0.86 for gastric cancer diagnosis with circulating miRNAs. In addition, subgroup analyses indicated that multiple miRNAs assays, non‑microarray screening approaches, and serum‑based miRNA assays exhibited good diagnostic performance in contrast to a single miRNA assay, microarray expression profiling screening, and plasma‑based miRNA group analysis. The diagnostic ability of miRNAs in early stage I‑II groups and the high expression group were approximately similar to that in the stage I‑IV groups and the low expression group. For the circulating miRNAs, our meta‑analysis identified a combination of multiple miRNAs, non‑microarray chip screening, and serum‑based miRNA assays were associated with the most effective GC diagnostic performance. However, many unclear molecular mechanisms limited the accuracy of the diagnostic results, and should be interpreted with caution. Further large‑scale prospective studies are required for validating the diagnostic applicability of circulating miRNAs in gastric cancer patients.

Zebrafish miR-462-731 regulates hematopoietic specification and pu.1-dependent primitive myelopoiesis

MicroRNAs (miRNAs) play significant roles in both embryonic hematopoiesis and hematological malignancy. Zebrafish miR-462-731 cluster is orthologous of miR-191-425 in human which regulates proliferation and tumorigenesis. In our previous work, miR-462-731 was found highly and ubiquitously expressed during early embryogenesis. In this study, by loss-of-function analysis (morpholino knockdown combined with CRISRP/Cas9 knockout) and mRNA profiling, we suggest that miR-462-731 is required for normal embryonic development by regulating cell survival. We found that loss of miR-462/miR-731 caused a remarkable decrease in the number of erythroid cells as well as an ectopic myeloid cell expansion at 48 hpf, suggesting a skewing of myeloid-erythroid lineage differentiation. Mechanistically, miR-462-731 provides an instructive input for pu.1-dependent primitive myelopoiesis through regulating etsrp/scl signaling combined with a novel pu.1/miR-462-731 feedback loop. On the other hand, morpholino (MO) knockdown of miR-462/miR-731 resulted in an expansion of posterior blood islands at 24 hpf, which is a mild ventralization phenotype resulted from elevation of BMP signaling. Rescue experiments with both BMP type I receptor inhibitor dorsomorphin and alk8 MO indicate that miR-462-731 acts upstream of alk8 within the BMP/Smad signaling pathway and functions as a novel endogenous BMP antagonist. Besides, an impairment of angiogenesis was observed in miR-462/miR-731 morphants. The specification of arteries and veins was also perturbed, as characterized by the irregular patterning of efnb2a and flt4 expression. Our study unveils a previously unrecognized role of miR-462-731 in BMP/Smad signaling mediated hematopoietic specification of mesodermal progenitors and demonstrates a miR-462-731 mediated regulatory mechanism driving primitive myelopoiesis in the ALPM. We also show a requirement for miR-462-731 in regulating arterial-venous specification and definitive hematopoietic stem cell (HSC) production. The current findings might provide further insights into the molecular mechanistic basis of miRNA regulation of embryonic hematopoiesis and hematological malignancy.

MicroRNAs as non-invasive diagnostic biomarkers for gastric cancer: Current insights and future perspectives

Non-invasive diagnostic biomarkers may contribute to an early identification of gastric cancer (GC) and improve the clinical management. Unfortunately, no sensitive and specific screening biomarkers are available yet and the currently available approaches are limited by the nature of the disease. GC is a heterogenic disease with various distinct genetic and epigenetic events that occur during the multifactorial cascade of carcinogenesis. MicroRNAs (miRNAs) are commonly deregulated in gastric mucosa during the Helicobacter pylori infection and in stepwise manner from chronic gastritis, through preneoplastic conditions such as atrophic gastritis and intestinal metaplasia, to early dysplasia and invasive cancer. Identification of miRNAs in blood in 2008 led to a great interest on miRNA-based diagnostic, prognostic biomarkers in GC. In this review, we provide the most recent systematic review on the existing studies related to miRNAs as diagnostic biomarkers for GC. Here, we systematically evaluate 75 studies related to differential expression of circulating miRNAs in GC patients and provide novel view on various heterogenic aspects of the existing data and summarize the methodological differences. Finally, we highlight several important aspects crucial to improve the future translational and clinical research in the field.

Oncogenic miR-425-5p is associated with cellular migration, proliferation and apoptosis in renal cell carcinoma

An increasing number of studies have demonstrated the function of microRNAs (miRNAs) in the initiation and development of various types of cancer. Among them, miR-425-5p is proven to serve an important function in several types of cancer, including gastric, cervical cancer, and hepatocellular carcinoma. However, the function of miR-425-5p in renal cell carcinoma (RCC) remains unclear. In the present study, it was demonstrated that the expression level of miR-425-5p was upregulated in RCC tissues and cell lines compared with normal tissues and cell lines (P<0.05). Additionally, Cell Counting kit-8 and MTT assays were employed to assess cell viability and proliferation, whereas wound healing and Transwell assays were employed to examine migration and invasion. The results demonstrated that upregulation of miR-425-5p promoted cell viability and the invasion and migration of ACHN and 786O cells (P<0.05). Flow cytometric analysis confirmed that upregulation of miR-425-5p inhibited apoptosis of ACHN and 786O cells (P<0.05). Downregulation of miR-425-5p inhibited the viability and invasion and migration of ACHN and 786O cells (P<0.05). In the present study, upregulation of miR-425-5p inhibited apoptosis of ACHN and 786O cells whereas no differences in early apoptotic rate were observed between the inhibitor and inhibitor NC groups for 786O and ACHN cells. These results indicate that miR-425-5p may act as an oncogene in RCC.

Clustered miRNAs and their role in biological functions and diseases

MicroRNAs (miRNAs) are endogenous, small non-coding RNAs known to regulate expression of protein-coding genes. A large proportion of miRNAs are highly conserved, localized as clusters in the genome, transcribed together from physically adjacent miRNAs and show similar expression profiles. Since a single miRNA can target multiple genes and miRNA clusters contain multiple miRNAs, it is important to understand their regulation, effects and various biological functions. Like protein-coding genes, miRNA clusters are also regulated by genetic and epigenetic events. These clusters can potentially regulate every aspect of cellular function including growth, proliferation, differentiation, development, metabolism, infection, immunity, cell death, organellar biogenesis, messenger signalling, DNA repair and self-renewal, among others. Dysregulation of miRNA clusters leading to altered biological functions is key to the pathogenesis of many diseases including carcinogenesis. Here, we review recent advances in miRNA cluster research and discuss their regulation and biological functions in pathological conditions.

Prader-Willi region non-protein coding RNA 1 suppressed gastric cancer growth as a competing endogenous RNA of miR-425-5p

Gastric cancer (GC) is one of the major global health problems, especially in Asia. Nowadays, long non-coding RNA (lncRNA) has gained significant attention in the current research climate such as carcinogenesis. This research desires to explore the mechanism of Prader-Willi region non-protein coding RNA 1 (PWRN1) on regulating GC process. Differentially expressed lncRNAs in GC tissues were screened out through microarray analysis. The RNA and protein expression level were detected by quantitative real-time PCR (qRT-PCR) and Western blot. Cell proliferation, apoptosis rate, metastasis abilities were respectively determined by cell counting kit 8 (CCK8), flow cytometry, wound healing, and transwell assay. The luciferase reporter system was used to verify the targetting relationships between PWRN1, miR-425-5p, and phosphatase and tensin homolog (PTEN). RNA-binding protein immunoprecipitation (RIP) assay was performed to prove whether PWRN1 acted as a competitive endogenous RNA (ceRNA) of miR-425-5p Tumor xenograft model and immunohistochemistry (IHC) were developed to study the influence of PWRN1 on tumor growth in vivo Microarray analysis determined that PWRN1 was differently expressed between GC tissues and adjacent tissues. qRT-PCR revealed PWRN1 low expression in GC tissues and cells. Up-regulated PWRN1 could reduce proliferation and metastasis and increase apoptosis in GC cells, while miR-425-5p had reverse effects. The RIP assay indicated that PWRN1 may target an oncogene, miR-425-5p The tumor xenograft assay found that up-regulated PWRN1 suppressed the tumor growth. The bioinformatics analysis, luciferase assay, and Western blot indicated that PWRN1 affected PTEN/Akt/MDM2/p53 axis via suppressing miR-425-5p Our findings suggested that PWRN1 functioned as a ceRNA targetting miR-425-5p and suppressed GC development via p53 signaling pathway.

Expression profile of circulating microRNAs in the Correa pathway of progression to gastric cancer

Background

Helicobacter pylori infection causes long-term chronic active gastritis, a risk factor for the intestinal and diffuse forms of gastric cancer. Most gastric cancers develop in a stepwise progression from chronic active gastritis to precursor lesions of gastric cancer. The early detection of gastric cancer improves survival. Studies with recent evidence have proposed circulating-microRNAs as biomarkers of cancer.

Objective

The purpose of this study was to explore the circulating-microRNA profile from H. pylori infection to gastric adenocarcinoma.

Methods

One hundred and twenty-three patients were enrolled and assigned to the discovery or the validation sets. In the discovery phase, circulating-microRNAs were measured by dye-based quantitative polymerase chain reaction and a selection of circulating-microRNAs was validated by probe-based quantitative polymerase chain reaction. A quality control protocol was used.

Results

One hundred and sixty-seven circulating-microRNAs were detected. Precursor lesions of gastric cancer and gastric cancer patients showed the downregulation of eight and five circulating-microRNAs, respectively. We further validated the deregulation of miR-196a-5p in precursor lesions of gastric cancer and the deregulation of miR-134-5p, miR-144-3p and miR-451a in gastric cancer. However, circulating-microRNAs exhibited moderate diagnostic performance due to the overlap of circulating-microRNA expression between non-cancer and cancer patients. miR-144-3p/miR-451a expression levels were correlated. Interestingly, these microRNAs are in 17q11.2, a site of rearrangements associated with gastric cancer.

Conclusion

Circulating-microRNAs are deregulated in precancerous and gastric cancer patients but efforts are needed to improve their diagnostic accuracy.

MicroRNA-191, regulated by HIF-2α, is involved in EMT and acquisition of a stem cell-like phenotype in arsenite-transformed human liver epithelial cells

Inorganic arsenic is widely distributed in the environment, and epidemiologic data show a strong association between arsenic exposure and risk of liver cancer. An understanding of the mechanisms underlying development of liver cancer and metastasis would be useful in reducing the incidence and mortality of liver cancer. MicroRNAs (miRs) act as regulators in liver cancer. Here, we show that acute or chronic exposure of human liver epithelial L-02 cells to arsenite increased expression of miR-191. There were decreased levels of BASP-1 and E-cadherin and increased levels of WT-1 and N-cadherin, indicating that arsenite induced epithelial-mesenchymal transition (EMT). Moreover, arsenite increased EpCAM and CD90 mRNA levels, showing the acquisition of stem cell-like properties by these cells. Suppression of miR-191 resulted in repression of EMT and reduced expression of stem-cell markers. Further, a miR-191 inhibitor blocked spheroid formation and production of side population cells. Luciferase reporter assays indicated that miR-191 was a target of HIF-2α, and inhibition of miR-191 decreased the neoplastic and metastatic properties of arsenite-transformed L-02 cells. Thus, in arsenite-transformed liver epithelial cells, transcriptional activation of the miR-191 promoter by HIF-2α is involved in EMT and in the acquisition of a stem cell-like phenotype.

Overexpression of miR-191 Predicts Poor Prognosis and Promotes Proliferation and Invasion in Esophageal Squamous Cell Carcinoma

PURPOSE

Accumulating evidence has shown that dysregulation of microRNA-191 (miR-191) is closely associated with tumorigenesis and progression in a wide range of cancers. This study aimed to explore the potential role of miR-191 in esophageal squamous cell carcinoma (ESCC).

MATERIALS AND METHODS

miR-191 expression was assessed in 93 ESCC tissue specimens by real-time polymerase chain reaction, and survival analysis was performed via Kaplan-Meier and Cox regression analyses. 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide, plate colony-forming, BrdU, and Transwell assays were conducted to observe the effect of miR-191 on ESCC proliferation and invasion. Luciferase reporter and western blot assays were taken to identify target genes of miR-191.

RESULTS

miR-191 was overexpressed in 93 cases of ESCC, compared with adjacent normal tissues, and miR-191 expression was significantly related to differentiation, depth of invasion, TNM stage, lymph node metastasis, and distant metastasis of tumor. Kaplan-Meier and Cox regression analyses demonstrated that overexpression of miR-191 was an independent and significant predictor of ESCC prognosis. Both gain-of-function and loss-of-function experiments showed that miR-191 promoted ESCC cell proliferation and invasion activities in vitro. Early growth response 1 (EGR1), a tumor suppressor, was predicted as a direct target of miR-191. Luciferase reporter and western blot assays proved that miR-191 reduced EGR1 expression by directly binding its 3' untranslated region. Moreover, EGR1 knockdown by siRNA enhanced ESCC cell growth and invasion.

CONCLUSION

Our findings provide specific biological roles of miR-191 in ESCC survival and progression. Targeting the novel miR-191/EGR1 axis represents a potential new therapeutic way to block ESCC development.

Identification of miRNA-mRNA Network Associated with Acute Myeloid Leukemia Survival

Background

Acute myeloid leukemia (AML) is a common hematologic malignancy of adults. The pathophysiological mechanism of AML is not well understood. The purpose of this study was to examine the crucial miRNAs and mRNAs associated with AML survival.

Material/Methods

The full clinical dataset of miRNA and mRNA expression profiling of AML patients was downloaded from The Cancer Genome Atlas database. Univariate Cox regression analysis was performed to obtain those miRNAs and mRNAs associated with AML survival. A miRNA-mRNA interaction network was constructed. The underlying functions of mRNAs were predicted through Kyoto Encyclopedia of Genes and Genomes (KEEG) pathway enrichment. The expression levels of miRNAs and mRNAs were detected by quantitative real-time polymerase chain reaction (qRT-PCR).

Results

Fourteen miRNAs and 830 mRNAs associated with AML survival were identified. Of the 14 miRNAs, hsa-mir-425, hsa-mir-1201, and hsa-mir-1978 were identified as risk factors and the other 11 miRNAs were identified as protective factors of AML survival. For target-genes of miRNAs, GTSF1, RTN4R, and CD44 were the top risk factor target-genes associated with AML survival. An interaction network was constructed that including 607 miRNA-target gene pairs associated with AML survival. Target-genes associated with AML survival were significantly enriched in several pathways including pancreatic secretion, calcium signaling pathway, natural killer cell mediated cytotoxicity, and Alzheimer’s disease. The qRT-PCR results were consistent with our bioinformatics analyses.

Conclusions

The miRNA hsa-mir-425 was identified as the top risk factor miRNA of AML survival and CD44 was identified as one of the top three risk factor target-genes associated with AML survival. Both hsa-mir-425 and CD44 may play key roles in progression and development of AML through calcium signaling pathway and natural killer cell mediated cytotoxicity.

Enhanced efficacy of anti-miR-191 delivery through stearylamine liposome formulation for the treatment of breast cancer cells

MicroRNAs are gaining rapid attention as promising targets for cancer treatment; however, efficient delivery of therapeutic miRNA or anti-miRNA into cancer cells remains a major challenge. Our previous work identified miR-191 as an oncogenic miRNA overexpressed in breast cancer that assists in progression of malignant transformation. Thus, inhibition of miR-191 using antisense miR-191 (anti-miR-191) has immense therapeutic potential. Here, we have developed a stearylamine (SA) based cationic liposome for delivery of miR-191 inhibitor (anti-miR-191), and studied its efficacy in breast cancer cells (MCF-7 and ZR-75-1) in culture. SA liposomes alone inhibited cancer cell growth with lesser IC_50s (50% inhibitory concentration) values as compared to normal mouse fibroblast cells (L929). The efficient delivery of anti-miR-191 in SA liposome complex was found to be highly effective in killing the cancer cells than a comparable dose of SA free anti-miR-191 liposome complex. The formulation also showed negligible cytotoxicity in human erythrocytes. Combined treatment of SA liposome with anti-miR-191 markedly enhanced apoptotic cell death and suppressed the migration of cancer cells in vitro. Notably, anti-miR-191 loaded SA liposome complex increased chemosensitivity of breast cancer cells to currently used anti-cancer drugs (doxorubicin or cisplatin) in free form. Our work demonstrates that anti-miR-191 loaded in SA liposome complex has promising clinical application for breast cancer therapy.

Involvement of the miR-462/731 cluster in hypoxia response in Megalobrama amblycephala

MicroRNAs (miRNAs) are non-coding small RNAs showing both evolutionarily conserved and unique features and are involved in nearly all biological processes. In the present study, the role played by miR-462/731 cluster miRNAs in hypoxia response in Megalobrama amblycephala, an important freshwater fish, was investigated. The M. amblycephala miR-462/731 cluster locus and their 5' flanking sequences were sequenced and analyzed. In M. amblycephala and other teleost fish species, the mature sequences of miR-462 and miR-731 were identical and hypoxia-responsive elements (HREs) were identified upstream of the miR-462/731 loci. The two miRNAs were significantly induced in the liver, spleen, gill, muscle, and brain after hypoxia treatment. The expression of both miRNAs was also upregulated in cells that received treatment which mimicked hypoxia. Furthermore, reporter assay revealed that M. amblycephala HREs can be activated by hypoxia. Taken together, the 462/731 cluster may play a role in the regulation of the hypoxia response in M. amblycephala.

Clinical value of miR-425-5p detection and its association with cell proliferation and apoptosis of gastric cancer

Researches have shown that miR-425-5p expression altered in lung, esophageal, and glial cancer. Similarly, in our previous study, we found miR-425-5p expression was up-regulated in GC cells and could promote gastric cancer (GC) cell invasion and metastasis. However, the functional mechanism and the prognostic significance of miR-425-5p in GC remain unclear. Therefore, the present study examined miR-425-5p expression in GC tissues and also evaluated miR-425-5p of the therapeutic and prognostic value. Moreover, with interference of miR-425-5p expression in cell lines, we investigated the molecular mechanism of miR-425-5p and the expression level was higher in GC tissues comparing with that in gastric tumor-adjacent mucosa. These results suggested that miR-425-5p over-expression may be associated with depth of invasion and TNM stages and can be a prognostic marker of poor outcome. After inhibition of miR-425-5p expression in MKN45 cells, the cell activity was weakened. The number of G0/G1 cells increased while G2/M and S cells decreased, and the cell apoptotic rates elevated (P<0.05). Some proliferation and apoptosis related genes were altered (P<0.05). Consequently, miR-425-5p can be considered as a marker of poor prognosis and it is probably involved in GC cell proliferation and apoptosis by regulating some of the genes which participate these processes.

Role of miRNAs and their potential to be useful as diagnostic and prognostic biomarkers in gastric cancer

Alterations in epigenetic control of gene expression play an important role in many diseases, including gastric cancer. Many studies have identified a large number of upregulated oncogenic miRNAs and downregulated tumour-suppressor miRNAs in this type of cancer. In this review, we provide an overview of the role of miRNAs, pointing to their potential to be useful as diagnostic and/or prognostic biomarkers in gastric cancer. Moreover, we discuss the influence of polymorphisms and epigenetic modifications on miRNA activity.

pol-miR-731, a teleost miRNA upregulated by megalocytivirus, negatively regulates virus-induced type I interferon response, apoptosis, and cell cycle arrest

Megalocytivirus is a DNA virus that is highly infectious in a wide variety of marine and freshwater fish, including Japanese flounder (Paralichthys olivaceus), a flatfish that is farmed worldwide. However, the infection mechanism of megalocytivirus remains largely unknown. In this study, we investigated the function of a flounder microRNA, pol-miR-731, in virus-host interaction. We found that pol-miR-731 was induced in expression by megalocytivirus and promoted viral replication at the early infection stage. In vivo and in vitro studies revealed that pol-miR-731 (i) specifically suppresses the expression of interferon regulatory factor 7 (IRF7) and cellular tumor antigen p53 in a manner that depended on the integrity of the pol-miR-731 complementary sequences in the 3′ untranslated regions of IRF7 and p53, (ii) disrupts megalocytivirus-induced Type I interferon response through IRF7, (iii) inhibits megalocytivirus-induced splenocyte apoptosis and cell cycle arrest through p53. Furthermore, overexpression of IRF7 and p53 abolished both the inhibitory effects of pol-miR-731 on these biological processes and its stimulatory effect on viral replication. These results disclosed a novel evasion mechanism of megalocytivirus mediated by a host miRNA. This study also provides the first evidence that a virus-induced host miRNA can facilitate viral infection by simultaneously suppressing several antiviral pathways.

miRNA-15a/16: as tumor suppressors and more

Since their first discovery in chronic lymphocytic leukemia, miR-15a and miR-16 have been reported to act as tumor suppressors or potential oncomiRs in different types of cancer. This review summarizes the history, biological properties and the important functions of these two miRNAs in cancer. It also introduces their roles as regulators of immune responses and angiogenesis, endogenous controls as well as potential targets and hallmarks of cancer.

Mycotoxin ochratoxin A disrupts renal development via a miR-731/prolactin receptor axis in zebrafish

Mycotoxin ochratoxin A (OTA) frequently contaminates various food and feed products, including cereals, coffee and wine. While the nephrotoxicity and teratogenicity of OTA have been extensively documented, the molecular mechanisms associated with OTA toxicity remained poorly understood in a developing organism. We showed that zebrafish embryos exposed to OTA demonstrated incorrect heart looping and small heart chambers. OTA also impaired the renal morphology and reduced the glomerular filtration rate of the embryonic zebrafish. The treatment of embryos with OTA attenuated the expression of the prolactin receptor, a gene (PRLRa) that has a key role in organogenesis and osmoregulation in vertebrates. OTA not only inhibited the phosphorylation of STAT5 and AKT, but also down-regulated the level of serpina1 mRNA in a dose-dependent manner. On the other hand, the microRNA profiling based on RNA sequencing revealed the up-regulation of microRNA-731 (miR-731) in the OTA-treated embryos. Further in silico analysis predicted that PRLRa was a target gene of miR-731. AntagomiR-731 restored PRLRa levels that had been reduced by OTA and also recovered the pronephros morphology that was damaged by OTA. These observations suggest that the exposure to OTA adversely affected the organogenesis of zebrafish, and the modulation of miR-731 and the PRLR signaling cascade contributed to the abnormal renal development mediated by OTA.

HIF-2α, acting via miR-191, is involved in angiogenesis and metastasis of arsenite-transformed HBE cells

Arsenic is a well established human carcinogen that causes diseases of the lung. Some studies have suggested that hypoxia-inducible factors (HIFs) and microRNAs (miRNAs) are involved in human lung cancer; however, their molecular mechanisms that causally contribute to arsenite-caused malignant transformation of cells remain unclear. To elucidate the mechanisms of angiogenesis and metastasis of lung cancer caused by arsenite, we investigated the role of HIF-2α regulation of miRNA-191 (miR-191) in the angiogenic and metastatic properties of human bronchial epithelial (HBE) cells transformed by arsenite. In HBE cells, HIF-2α binds to the hypoxia response element (HRE) in the promoter region of miR-191 and initiates transcription of miR-191. Blocking of HIF-2α with siRNA inhibited the up-regulation of miR-191, Wilms' tumor 1 (WT1) protein, matrix metalloproteinase 9 (MMP-9), vascular endothelial growth factor (VEGF), and the down-regulation of brain acid-soluble protein 1 (BASP1). In arsenite-transformed HBE (T-HBE) cells, down-regulation of HIF-2α by siRNA blocked the process of angiogenesis and decreased their neoplastic properties and metastatic capacity, which were reversed by over-expression of miR-191 or by up-regulating WT1. Thus, HIF-2α up-regulates WT1 via miR-191, both of which are involved in the angiogenesis and metastasis of T-HBE cells. The results present a better understanding of the processes involved in lung cancer caused by arsenite exposure.

Dysregulation of non-coding RNAs in gastric cancer

Gastric cancer (GC) is one of the most common cancers in the world and a significant threat to the health of patients, especially those from China and Japan. The prognosis for patients with late stage GC receiving the standard of care treatment, including surgery, chemotherapy and radiotherapy, remains poor. Developing novel treatment strategies, identifying new molecules for targeted therapy, and devising screening techniques to detect this cancer in its early stages are needed for GC patients. The discovery of non-coding RNAs (ncRNAs), primarily microRNAs (miRNAs) and long non-coding RNAs (lncRNAs), helped to elucidate the mechanisms of tumorigenesis, diagnosis and treatment of GC. Recently, significant research has been conducted on non-coding RNAs and how the regulatory dysfunction of these RNAs impacts the tumorigenesis of GC. In this study, we review papers published in the last five years concerning the dysregulation of non-coding RNAs, especially miRNAs and lncRNAs, in GC. We summarize instances of aberrant expression of the ncRNAs in GC and their effect on survival-related events, including cell cycle regulation, AKT signaling, apoptosis and drug resistance. Additionally, we evaluate how ncRNA dysregulation affects the metastatic process, including the epithelial-mesenchymal transition, stem cells, transcription factor activity, and oncogene and tumor suppressor expression. Lastly, we determine how ncRNAs affect angiogenesis in the microenvironment of GC. We further discuss the use of ncRNAs as potential biomarkers for use in clinical screening, early diagnosis and prognosis of GC. At present, no ideal ncRNAs have been identified as targets for the treatment of GC.

Next generation sequencing profiling identifies miR-574-3p and miR-660-5p as potential novel prognostic markers for breast cancer

Background

Prognostication of Breast Cancer (BC) relies largely on traditional clinical factors and biomarkers such as hormone or growth factor receptors. Due to their suboptimal specificities, it is challenging to accurately identify the subset of patients who are likely to undergo recurrence and there remains a major need for markers of higher utility to guide therapeutic decisions. MicroRNAs (miRNAs) are small non-coding RNAs that function as post-transcriptional regulators of gene expression and have shown promise as potential prognostic markers in several cancer types including BC.

Results

In our study, we sequenced miRNAs from 104 BC samples and 11 apparently healthy normal (reduction mammoplasty) breast tissues. We used Case–control (CC) and Case-only (CO) statistical paradigm to identify prognostic markers. Cox-proportional hazards regression model was employed and risk score analysis was performed to identify miRNA signature independent of potential confounders. Representative miRNAs were validated using qRT-PCR. Gene targets for prognostic miRNAs were identified using in silico predictions and in-house BC transcriptome dataset. Gene ontology terms were identified using DAVID bioinformatics v6.7. A total of 1,423 miRNAs were captured. In the CC approach, 126 miRNAs were retained with predetermined criteria for good read counts, from which 80 miRNAs were differentially expressed. Of these, four and two miRNAs were significant for Overall Survival (OS) and Recurrence Free Survival (RFS), respectively. In the CO approach, from 147 miRNAs retained after filtering, 11 and 4 miRNAs were significant for OS and RFS, respectively. In both the approaches, the risk scores were significant after adjusting for potential confounders. The miRNAs associated with OS identified in our cohort were validated using an external dataset from The Cancer Genome Atlas (TCGA) project. Targets for the identified miRNAs were enriched for cell proliferation, invasion and migration.

Conclusions

The study identified twelve non-redundant miRNAs associated with OS and/or RFS. These signatures include those that were reported by others in BC or other cancers. Importantly we report for the first time two new candidate miRNAs (miR-574-3p and miR-660-5p) as promising prognostic markers. Independent validation of signatures (for OS) using an external dataset from TCGA further strengthened the study findings.

Electronic supplementary material

The online version of this article (doi:10.1186/s12864-015-1899-0) contains supplementary material, which is available to authorized users.

Recent advances in the molecular diagnostics of gastric cancer

Gastric cancer (GC) is the third most common cause of cancer-related death in the world, representing a major global health issue. Although the incidence of GC is declining, the outcomes for GC patients remain dismal because of the lack of effective biomarkers to detect early GC and predict both recurrence and chemosensitivity. Current tumor markers for GC, including serum carcinoembryonic antigen and carbohydrate antigen 19-9, are not ideal due to their relatively low sensitivity and specificity. Recent improvements in molecular techniques are better able to identify aberrant expression of GC-related molecules, including oncogenes, tumor suppressor genes, microRNAs and long non-coding RNAs, and DNA methylation, as novel molecular markers, although the molecular pathogenesis of GC is complicated by tumor heterogeneity. Detection of genetic and epigenetic alterations from gastric tissue or blood samples has diagnostic value in the management of GC. There are high expectations for molecular markers that can be used as new screening tools for early detection of GC as well as for patient stratification towards personalized treatment of GC through prediction of prognosis and drug-sensitivity. In this review, the studies of potential molecular biomarkers for GC that have been reported in the publicly available literature between 2012 and 2015 are reviewed and summarized, and certain highlighted papers are examined.

Two Virus-Induced MicroRNAs Known Only from Teleost Fishes Are Orthologues of MicroRNAs Involved in Cell Cycle Control in Humans

MicroRNAs (miRNAs) are ~22 base pair-long non-coding RNAs which regulate gene expression in the cytoplasm of eukaryotic cells by binding to specific target regions in mRNAs to mediate transcriptional blocking or mRNA cleavage. Through their fundamental roles in cellular pathways, gene regulation mediated by miRNAs has been shown to be involved in almost all biological phenomena, including development, metabolism, cell cycle, tumor formation, and host-pathogen interactions. To address the latter in a primitive vertebrate host, we here used an array platform to analyze the miRNA response in rainbow trout (Oncorhynchus mykiss) following inoculation with the virulent fish rhabdovirus Viral hemorrhagic septicaemia virus. Two clustered miRNAs, miR-462 and miR-731 (herein referred to as miR-462 cluster), described only in teleost fishes, were found to be strongly upregulated, indicating their involvement in fish-virus interactions. We searched for homologues of the two teleost miRNAs in other vertebrate species and investigated whether findings related to ours have been reported for these homologues. Gene synteny analysis along with gene sequence conservation suggested that the teleost fish miR-462 and miR-731 had evolved from the ancestral miR-191 and miR-425 (herein called miR-191 cluster), respectively. Whereas the miR-462 cluster locus is found between two protein-coding genes (intergenic) in teleost fish genomes, the miR-191 cluster locus is found within an intron of a protein-coding gene (intragenic) in the human genome. Interferon (IFN)-inducible and immune-related promoter elements found upstream of the teleost miR-462 cluster locus suggested roles in immune responses to viral pathogens in fish, while in humans, the miR-191 cluster functionally associated with cell cycle regulation. Stimulation of fish cell cultures with the IFN inducer poly I:C accordingly upregulated the expression of miR-462 and miR-731, while no stimulatory effect on miR-191 and miR-425 expression was observed in human cell lines. Despite high sequence conservation, evolution has thus resulted in different regulation and presumably also different functional roles of these orthologous miRNA clusters in different vertebrate lineages.

microRNA-425-5p is upregulated in human gastric cancer and contributes to invasion and metastasis in vitro and in vivo

Emerging evidence indicates that microRNAs are involved in the development and progression of gastric cancer (GC), functioning as tumor suppressors or oncogenes. The aim of the current study was to explore the potential mechanism of microRNA-425-5p (miR-425-5p) in GC. Using reverse transcription quantitative polymerase chain reaction, miR-425-5p expression was detected in GC cell lines (SGC-7901, MKN-28, MKN-45, BGC-823 and AGS) and the GES-1 cell line. Cell proliferation, soft agar colony formation, flow cytometry, haptotactic migration and matrigel chemoinvasion assays were used to test the proliferation, apoptosis, invasion and migration of BGC-823 cells transfected with miR-425-5p mimics or an inhibitor. Female BALB/c mice were randomly divided into three groups. Each experimental group contained five mice. BGC 823 cells were stably transfected with miR-425-5p inhibitor, wild type or negative control and were injected into the mice through the tail vein. It was found that miR-425-5p expression was significantly upregulated in all the GC cell lines when compared with the GES-1 cell line. Downregulation of miR-425-5p expression inhibited GC cell proliferation, invasion and migration. In the in vivo studies, downregulation of miR-425-5p expression suppressed pulmonary metastasis in the nude mice. Thus, miR-425-5p was demonstrated to have the potential to become a novel metastasis-associated gene; however, the mechanisms associated with these effects require further study. In the future, the development of miR-425-5p as a novel therapeutic strategy for the treatment of GC may be possible.

Characterization of microRNA transcriptome in tumor, adjacent, and normal tissues of lung squamous cell carcinoma

OBJECTIVES

MicroRNAs are a class of regulatory molecules involved in a wide variety of biological processes, including growth, development, and apoptosis. Given the widespread roles of microRNAs in biological processes, understanding their different expression profiles in normal, adjacent, and tumor tissues will provide insights into the consequences of aberrant expression.

METHODS

With the use of next-generation deep sequencing technology, microRNA profiles in 3 pooled samples from normal, adjacent, and tumor tissues of 19 patients with lung squamous cell carcinoma were characterized comprehensively. Quantitative polymerase chain reaction was used to verify the primary findings in another 38 lung squamous cell carcinoma tumor samples. In situ hybridization also was performed for validation.

RESULTS

A total of 368, 306, and 231 known microRNAs were identified from tumor, adjacent, and normal pooled samples, respectively, of which 40, 44, and 26 microRNAs displayed dysregulation with 2-fold or greater change in 3 compared groups of tumor versus normal, tumor versus adjacent, and adjacent versus normal, respectively. Sequencing data also showed that some coexpressed microRNAs displayed a pattern of progressive dysregulation. Some of the microRNAs exhibited consistent changes; among them, miR-425-5p and miR-218-5p were confirmed by quantitative polymerase chain reaction and in situ hybridization, and proved that the microRNA expression levels were closely related to tumor stages and sizes. It is suggested that some microRNAs, such as miR-425 and miR-183, might be a driver for tumor formation, growth, and progression to higher staging, whereas others, such as miR-218, might behave as a tumor suppressor in lung cancer. Functional annotation analysis indicated that the proteoglycan pathway in cancer and mitogen-activated protein kinase, Wnt, PI3K-Akt, and transforming growth factor-beta signaling pathways might be involved in the pathogenesis of lung squamous cell carcinoma.

CONCLUSIONS

This study describes the use of deep sequencing for comprehensive profiling of microRNAs in lung squamous cell carcinoma. The identified microRNA signatures may provide biomarkers for early detection, subclassification, and potential therapeutic targets of lung squamous cell carcinoma. This study also provides some insights into the molecular mechanism underlying the development and progression of lung squamous cell carcinoma, which may prove helpful for early diagnosis and treatment of the disease.