miR-210: a therapeutic target in cancer

miRNA Expression May Have Implications for Immunotherapy in PDGFRA Mutant GISTs

Gastrointestinal stromal tumors (GISTs) harboring mutations in the PDGFRA gene occur in only about 5-7% of patients. The most common PDGFRA mutation is exon 18 D842V, which is correlated with specific clinico-pathological features compared to the other PDGFRA mutated GISTs. Herein, we present a miRNA expression profile comparison of PDGFRA D842V mutant GISTs and PDGFRA with mutations other than D842V (non-D842V). miRNA expression profiling was carried out on 10 patients using a TLDA miRNA array. Then, miRNA expression was followed by bioinformatic analysis aimed at evaluating differential expression, pathway enrichment, and miRNA-mRNA networks. We highlighted 24 differentially expressed miRNAs between D842V and non-D842V GIST patients. Pathway enrichment analysis showed that deregulated miRNAs targeted genes that are mainly involved in the immune response pathways. The miRNA-mRNA networks highlighted a signature of miRNAs/mRNA that could explain the indolent behavior of the D842V mutated GIST. The results highlighted a different miRNA fingerprint in PDGFRA D842V GISTs compared to non-D842Vmutated patients, which could explain the different biological behavior of this GIST subset.

Circulating exosomal microRNAs as novel potential detection biomarkers in pancreatic cancer

Circulating exosomal microRNAs (ex-miRNAs) are reflective of the characteristics of the tumor and are valuable biomarkers in different types of tumor. In addition, miRNAs serve important roles in tumor progression and metastasis. The present study aimed to investigate the circulating ex-miRNA-21 and miRNA-210 as novel biomarkers for patients with pancreatic cancer (PC). For this purpose, serum ex-miRNAs were extracted from the serum of patients with PC (n=30) and chronic pancreatitis (CP) (n=10) using an RNA isolation kit. For exosome identification in serum, transmission electron micrographs were used to determine crystalline structure, western blotting was used to identify exosomal markers, and NanoSight was used for nanoparticle characterization. The relative expression levels of ex-miRNAs were quantified using quantitative PCR and compared between patients with PC and CP. The expression levels of both ex-miRNA-21 and miRNA-210 were significantly higher in patients with PC compared with patients with CP (both P<0.001). However, no significant difference in the relative serum levels of free miR-21 and miR-210 was observed between the 2 groups of patients (both P>0.05). ex-miRNA-21 and miRNA-210 were associated with tumor stage, as well as other factors. The diagnostic potential of ex-miRNA-21 and miRNA-210 levels was 83 and 85%, respectively. In addition, when ex-miRNA and serum carbohydrate antigen 19-9 expression levels were combined, the accuracy increased to 90%. The present study identified that serum ex-miRNAs, miRNA-21 and miRNA-210 may be of value as potential biomarkers and therapeutic targets for the diagnosis and treatment of PC.

MicroRNA‑4500 suppresses tumor progression in non‑small cell lung cancer by regulating STAT3

Research has revealed that microRNA (miR)-4500 is downregulated in non-small cell lung cancer (NSCLC), and miR-4500 suppresses tumor growth by targeting lin-28 homolog B and NRAS proto-oncogene, GTPase. In the present study, it was reported that signal transducer and activator of transcription 3 (STAT3) may function as a novel target gene for miR-4500 in NSCLC. The experiments conducted in the present study confirmed that the miR-4500 expression was decreased in NSCLC tissues and cells compared with adjacent normal tissues and a normal lung cell line. miR-4500 suppressed the cell proliferation, migration, invasion and promoted apoptosis of the human NSCLC cell lines A549 and H1975. Expression of STAT3 was negatively correlated with miR-4500 expression in vivo. A luciferase reporter assay suggested that miR-4500 directly targeted the 3′ untranslated region of STAT3. The tumor inhibition effect of small interfering RNA STAT3 in A549 and H1975 lines may be partially impaired by a miR-4500 inhibitor. The results of the present study suggests that miR-4500 may be a tumor suppressor and a potential therapeutic target in NSCLC.

miRNA‑30a‑3p inhibits metastasis and enhances radiosensitivity in esophageal carcinoma by targeting insulin‑like growth factor 1 receptor

It has been demonstrated that microRNAs (miRNAs) serve important roles in various biological processes, such as tumorigenesis. In the present study, the role of miR‑30a‑3p in the pathogenesis of esophageal carcinoma (EC) was investigated. Reverse transcription‑quantitative polymerase chain reaction was performed to determine the levels of miR‑30a‑3p expression in EC tissues and cell lines. Then, the effects of miR‑30a‑3p on the migration, invasion and radiosensitivity of EC cells were investigated using scratch‑wound, Transwell and radiosensitivity assays, respectively. A dual‑luciferase reporter assay was performed to determine potential interactions between miR‑30a‑3p and the 3'‑untranslated region (3'‑UTR) of insulin‑like growth factor 1 receptor (IGF‑1R). The results demonstrated that the levels of miR‑30a‑3p expression in EC tissues and cell lines were significantly decreased compared with those in paired healthy tissues and a human esophageal epithelial cell line. Upregulation of miR‑30a‑3p expression significantly suppressed migration, invasion and epithelial‑mesenchymal transition (EMT), and enhanced radiosensitivity in EC cells. Analysis of luciferase activity demonstrated that miR‑30a‑3p interacted with the 3'‑UTR of IGF‑1R, and knockdown of IGF‑1R induced similar effects on the migration, invasion, EMT and radiosensitivity of EC cells. The results indicated that miR‑30a‑3p suppressed metastasis and enhanced the radiosensitivity of EC cells via downregulation IGF‑1R, suggesting that miR‑30a‑3p may be a potential therapeutic target in the treatment of EC.

Diagnostic significance of miR-210 as a potential tumor biomarker of human cancer detection: an updated pooled analysis of 30 articles

A large number of studies have explored the diagnostic value of miR-210 as a potential diagnostic cancer biomarker to detect various cancers in patients. However, the results of its diagnostic accuracy and reliability in individual studies are still inconsistent. Therefore, we conducted this updated pooled analysis to derive a more reliable conclusion of the overall accuracy of miR-210 in cancer detection and diagnosis. A comprehensive literature search was performed using the PubMed, Cochrane Library, Web of Science, China National Knowledge Infrastructure, and Wanfang databases. The quality of all eligible studies was scored according to Quality Assessment of Diagnostic Accuracy Studies-2 guidelines. The bivariate mixed model was applied to pooled sensitivity, specificity, likelihood ratios, and diagnostic ORs. The summary receiver operator characteristic (SROC) curve and the hierarchical SROC models were used to check overall diagnostic performance. Thirty articles with 2,304 patients and 1,673 controls were included in this study. The pooled parameters calculated from all studies are as follows: sensitivity -0.74 (95% CI: 0.68-0.79), specificity -0.79 (95% CI: 0.74-0.83), positive likelihood ratio -3.57 (95% CI: 2.85-4.47), negative likelihood ratio -0.32 (95% CI: 0.26-0.40), diagnostic OR -10.98 (95% CI: 7.55-15.98), SROC -0.84 (95% CI: 0.80-0.87). All of these results revealed that miR-210 had relatively moderate accuracy in distinguishing patients with various cancers from all other individuals. However, well-designed prospective studies with large sample sizes using different groups of the population are urgently warranted to confirm our findings.

Dexamethasone-induced inhibition of miR-132 via methylation promotes TGF-β-driven progression of pancreatic cancer

Glucocorticoids (GCs) such as dexamethasone (DEX) are administered as cancer co-treatment for palliative purposes due to their pro-apoptotic effects in lymphoid cancer and limited side effects associated with cancer growth and chemotherapy. However, there is emerging evidence that GCs induce therapy resistance in most epithelial tumors. Our recent data reveal that DEX promotes the progression of pancreatic ductal adenocarcinoma (PDA). In the present study, we examined 1 primary and 2 established PDA cell lines, and 35 PDA tissues from patients who had received (n=14) or not received (n=21) GCs prior to surgery. Through microRNA microarray analysis, in silico, and RT-qPCR analyses, we identified 268 microRNAs differentially expressed between DEX-treated and untreated cells. With a focus on cancer progression, we selected miR-132 and its target gene, transforming growth factor-β2 (TGF-β2), as top candidates. miR-132 mimics directly bound to the 3′ untranslated region (3′UTR) of a TGF-β2 luciferase construct and enhanced expression, as shown by increased luciferase activity. By contrast, DEX inhibited miR-132 expression via promoter methylation. miR-132 mimics also reduced DEX-induced clonogenicity, migration and expression of vimentin and E-cadherin in vitro and in tumor xenografts. In patients, GC intake prior to surgery enhanced global hypermethylation and expression of TGF-β2 in tissues; expression of miR-132 was detected but could not be quantified. Our results demonstrate that DEX-mediated inhibition of miR-132 is a key mediator in the progression of pancreatic cancer, and the findings provide a foundation for miRNA-based therapies.

MicroRNA-21 contributes to the discrimination of chemoresistance in metastatic gastric cancer

BACKGROUND

Multidrug resistance in gastric cancer greatly impedes the efficacy of chemotherapy.

OBJECTIVE

To explore the efficacy of microRNA-21 (mir-21) in distinguishing metastatic gastric cancer (MGC) with chemoresistance.

METHODS

From April 2012 to May 2015, 92 MGC patients were enrolled. Cisplatin and fluorouracil-based systemic chemotherapy was given, and patients' characteristics and follow-up data were collected. In addition, miR-21 expression was determined in tumor tissue and plasma.

RESULTS

Sixty-seven patients responded to chemotherapy, and chemotherapy resistance was observed in 25 patients. miR-21 expression in tumor tissue and plasma was significantly elevated in the chemotherapy-resistant group (CRG) compared to the chemotherapy-sensitive group (CSG) (p< 0.001). miR-21 expression in tissue was associated with tumor differentiation (p= 0.042), and plasma miR-21 was correlated with gender (p= 0.016), tumor differentiation (p= 0.003), and number of metastatic sites (p< 0.001). Receiver operating characteristic (ROC) analysis indicated that miR-21 in tissue yielded an area under the ROC curve (AUC) of 0.830 (95%CI: 0.737-0.900, sensitivity: 88.0%, specificity: 68.7%) in distinguishing CRG from CSG; and plasma miR-21 yielded an AUC of 0.759 (95%CI: 0.658-0.842, sensitivity: 52.0%, specificity: 88.1%) in distinguishing CRG form CSG. Log-rank test and Cox proportional hazard regression analysis indicated that patients with higher miR-21 expression in tissue and plasma experienced shorter overall survival (P< 0.001).

CONCLUSION

miR-21 could serve as a potential biomarker to identify MGC with chemoresistance.

Hypoxia-regulated gene expression explains differences between melanoma cell line-derived xenografts and patient-derived xenografts

Cell line-derived xenografts (CDXs) are an integral part of drug efficacy testing during development of new pharmaceuticals against cancer but their accuracy in predicting clinical responses in patients have been debated. Patient-derived xenografts (PDXs) are thought to be more useful for predictive biomarker identification for targeted therapies, including in metastatic melanoma, due to their similarities to human disease. Here, tumor biopsies from fifteen patients and ten widely-used melanoma cell lines were transplanted into immunocompromised mice to generate PDXs and CDXs, respectively. Gene expression profiles generated from the tumors of these PDXs and CDXs clustered into distinct groups, despite similar mutational signatures. Hypoxia-induced gene signatures and overexpression of the hypoxia-regulated miRNA hsa-miR-210 characterized CDXs. Inhibition of hsa-miR-210 with decoys had little phenotypic effect in vitro but reduced sensitivity to MEK1/2 inhibition in vivo, suggesting down-regulation of this miRNA could result in development of resistance to MEK inhibitors.

Precise Regulation of miR-210 Is Critical for the Cellular Homeostasis Maintenance and Transplantation Efficacy Enhancement of Mesenchymal Stem Cells in Acute Liver Failure Therapy

Stem cell transplantation is a promising clinical strategy to cure acute liver failure. However, a low cell survival ratio after transplantation significantly impairs its therapeutic efficacy. This is partly due to insufficient resistance of transplanted stem cells to severe oxidative and inflammatory stress at the injury sites. In the current study, we demonstrated that a small molecule zeaxanthin dipalmitate (ZD) could enhance the defensive abilities against adverse stresses of human adipose-derived mesenchymal stem cells (hADMSCs) in vitro and increase their therapeutic outcomes of acute liver failure after transplantation in vivo. Treatment with ZD dramatically improved cell survival and suppressed apoptosis, inflammation, and reactive oxygen species (ROS) production of hADMSCs through the PKC/Raf-1/MAPK/NF-κB pathway to maintain a reasonably high expression level of microRNA-210 (miR-210). The regulation loop between miR-210 and cellular/mitochondrial ROS production was found to be linked by the ROS inhibitor iron-sulfur cluster assembly proteins (ISCU). Pretreatment with ZD and stable knockdown of miR-210 significantly improved and impaired the stem cell transplantation efficacy through the alteration of hepatic cell expansion and injury amelioration, respectively. Vehicle treatment with ZD did not pose any adverse effect on cell homeostasis or healthy animal. In conclusion, elevating endogenous antioxidant level of hADMSCs with ZD significantly enhances their hepatic tissue-repairing capabilities. Maintenance of a physiological level of miR-210 is critical for hADMSC homeostasis.

MicroRNA-210 promotes cancer angiogenesis by targeting fibroblast growth factor receptor-like 1 in hepatocellular carcinoma

Hypoxia drives cancer to become more aggressive, particularly angiogenesis, and the corresponding mechanisms still need to be further investigated. In hepatocellular carcinoma (HCC), the master hypoxia-induced microRNA (miRNA) miR-210 is upregulated in HCC and participates in HCC progression, but its roles in hypoxia-induced HCC angiogenesis are still unknown. Moreover, the correlation between miR-210 expression and HCC clinical progression also needs elucidation. In the present study, we found that miR-210 expression was progressively increased from normal liver and adjacent non-tumor tissues, to incipient and advanced tumor tissues. In HCC patients, high miR-210 expression was significantly correlated with poor prognosis, both tumor-free survival and overall survival. Moreover, miR-210 expression in HCC was significantly positively correlated with microvascular density. Both in vitro and in vivo studies determined that miR-210 promoted HCC angiogenesis, and the corresponding mechanism was identified to be the direct targeting and inhibition of fibroblast growth factor receptor-like 1 (FGFRL1) expression. Thus, we suggest a new prognosis predictor for HCC patients, and determined the roles of hypoxic miR-210 in HCC angiogenesis.

Co-expressed miRNAs in gastric adenocarcinoma

Co-expression networks may provide insights into the patterns of molecular interactions that underlie cellular processes. To obtain a better understanding of miRNA expression patterns in gastric adenocarcinoma and to provide markers that can be associated with histopathological findings, we performed weighted gene correlation network analysis (WGCNA) and compare it with a supervised analysis. Integrative analysis of target predictions and miRNA expression profiles in gastric cancer samples was also performed. WGCNA identified a module of co-expressed miRNAs that were associated with histological traits and tumor condition. Hub genes were identified based on statistical analysis and network centrality. The miRNAs 100, let-7c, 125b and 99a stood out for their association with the diffuse histological subtype. The 181 miRNA family and miRNA 21 highlighted for their association with the tumoral phenotype. The integrated analysis of miRNA and gene expression profiles showed the let-7 miRNA family playing a central role in the regulatory relationships.

MicroRNA-210 and its theranostic potential

INTRODUCTION

MicroRNAs (miRNAs) are a set of small single-stranded noncoding RNAs with diverse biological functions. As a prototypical hypoxamir, human microRNA-210 (hsa-miR-210) is one of the most widely studied miRNAs thus far. In addition to its involvement in sophisticated regulation of numerous biological processes, miR-210 has also been shown to be associated with the development of different human diseases including various types of cancers, cardiovascular and cerebrovascular diseases, and immunological diseases. Given its multi-faceted functions, miR-210 may serve as a novel and promising theranostic target for prevention and treatment of diseases. Areas covered: This review aims to provide a comprehensive overview of miR-210, the regulation of its expression, biological functions and molecular mechanisms, with particular emphasis on its diagnostic and therapeutic potential. Expert opinion: Although the exact roles of miR-210 in various diseases have not been fully clarified, targeting miR-210 may be a promising therapeutic strategy. Further investigations are also needed to facilitate therapeutic-clinical applications of miR-210 in human diseases.

Role of microRNA-210 in human intervertebral disc degeneration

The present study aimed to investigate the role of microRNA (miR)-210 in the development of intervertebral disc degeneration (IDD). Human nucleus pulposus (NP) samples were collected from patients with scoliosis and IDD (n=12 each) as the scoliosis control and IDD groups, respectively. The expression levels of miR-210 were detected using reverse-transcription quantitative polymerase chain reaction. In vitro overexpression and knockdown of miR-210 in human NP cells were achieved by transfection of NP cells with lentiviral pre-miR-210 and antagomiR-210, respectively. The protein expression levels of homeobox A9 (HOXA9) were then detected in NP cells with modulated miR-210 using western blot analysis. Flow cytometry with allophycocyanin-Annexin V/7 and 7-aminoactinomycin D staining was also used to detect the proportion of NP cells with modulated miR-210 undergoing apoptosis. The current study revealed that the miR-210 expression was decreased in patients with IDD compared with that of the scoliosis control group (P<0.05). Furthermore, the upregulation of miR-210 with pre-miR-210 led to the repression of HOXA9. The HOXA9 level was significantly lower in these cells compared with that of NP cells treated with a corresponding negative sequence (P<0.05). Knockdown of miR-210 with antagomiR-210 resulted in upregulation of HOXA9 in NP cells, determined as the level of HOXA9 was significantly higher than that of NP cells treated with a negative sequence (P<0.05). The proportion of apoptotic NP cells also significantly decreased following treatment with pre-miR-210 compared with the scoliosis control group (12.1±1.43 vs. 23.8±1.22%, respectively; P<0.05). In conclusion, downregulation of miR-210 may promote Fas-mediated apoptosis in human IDD by regulating the expression of HOXA9. This indicates that miR-210 may be closely associated with the development of IDD and may act as a novel target in IDD treatment.

The Pleiotropic Effects of miRNAs on Tumor Angiogenesis

Angiogenesis, the process of new blood vessel formation and growth from already existing venules is critical in vascular development and homeostasis controlled by the balance of pro- and anti-angiogenic factors. Emerging evidence indicates the development, progression, and metastasis of various human cancers are strongly relied on angiogenesis. However, molecular mechanisms that underlie the complex regulation of angiogenic processes are still not fully elucidated. Recent studies revealed that microRNAs (miRNAs) were important regulators of tumor angiogenesis and the entire research in this area has entered into a so-called "miRNAs era." Thus, miRNAs might be important therapeutic targets or biomarkers for cancer. Due to the complexity of miRNA regulating mechanisms, how specific miRNAs intersect with and modulate tumor angiogenesis is still unclear. The conflicting results of the same miRNAs from different groups indicated that miRNAs might possess potent activity in a cell type or cell context specific manner. Here, we present a summary of latest advances in understanding the roles of angiogenic miRNAs as potential tools or targets in cancer therapy.

Oxidized low-density lipoprotein is a common risk factor for cardiovascular diseases and gastroenterological cancers via epigenomical regulation of microRNA-210

Hyperlipidemia, including the oxidized low-density lipoprotein (oxLDL) accumulation, is a risk and highly associated with the development of cancers and cardiovascular diseases. microRNA-210 (miR-210), a hypoxia-responsive microRNA regulated by HIF-1α, has been implicated in cancer and cardiovascular disease formation. Furthermore, Bioinformatics analysis revealed that the promoter of the miR-210 gene contains CpG-rich regions. It is unclear whether miR-210 expression could be epigenetically regulated in these disease progresses. The study aimed to explore the relationships between lipid and miR-210 in the context of cardiovascular disease and gastrointestinal cancer. We demonstrated oxLDL can decrease methylation in the miR-210 promoter to up-regulate miR-210. HIF-1α can bind to miR-210 promoter, but this HIF-1α binding site can be blocked by methylation. We showed that subjects of carotid atherosclerosis, stroke patients and cancer patients had hypomethylation in the miR-210 promoter, especially the HIF-1α binding site. Furthermore, miR-210 can directly inhibit sprouty-related EVH1 domain 2 (SPRED2) expressions, and SPRED2 reduces cell migration via ERK/c-Fos/MMPs pathways. Increased miR-210 and reduced SPRED2 levels were found in aorta of mice under high-fat diet and tumor tissues, which implied that miR-210 can be an underlying mechanism to explain oxLDL as a common risk factor for cardiovascular disease and gastrointestinal cancer.

Genetic alteration regulated by microRNAs in biliary tract cancers

Biliary tract cancers (BTCs) constitute a relatively rare but highly malignant class of tumors with poor prognosis including gallbladder cancer, intra- and extra-hepatic cholangiocarcinoma. Recently, accumulated evidences have demonstrated that deregulated expression of microRNAs (miRNAs) is closely associated with the development, invasion, metastasis and prognosis of different cancers including BTCs. MiRNAs comprise an endogenously expressed and highly evolutionarily conserved group of small, non-coding, single-stranded RNAs which negatively regulate target genes expression by means of combining with 3' untranslated region (UTR) of corresponding mRNAs at the post-transcriptional level with significant roles in various fundamental cellular procedures including cell proliferation, differentiation, migration, cell cycle control and apoptosis. Recent studies have indicated that miRNAs could function as novel tumor-promoting genes or tumor suppressor genes to act as potential therapeutic targets in anticancer treatment because the genetic alteration regulated by miRNAs could result in tumorigenesis and tumor inhibition. Anomalous miRNAs expression patterns, acting as phenotypic signatures of distinct cancers, are promising to be used as diagnostic, prognostic, predictive biomarkers. In this review, we summarize the current findings from the studies about potential genetic alteration regulated by miRNAs and their roles in BTCs.

MicroRNA expression profiles predict clinical phenotypes and prognosis in chromophobe renal cell carcinoma

Chromophobe renal cell carcinoma (chRCC) is the third most common subtype of kidney cancers. In the present study, we identified 58 treatment-naïve primary chRCC patients from The Cancer Genome Atlas dataset and analyzed the genome-wide microRNA (miRNA) expression profiles, with the aim to assess the relationship of miRNA expression with the progression and prognosis of chRCC. Overall, a total of 105 miRNAs were found to be differentially expressed between tumor and the adjacent normal tissues from 22 chRCC patients. In the unpaired condition (58 chRCC vs. 22 normal tissues), 77 (96.3%) samples were distinguished correctly by the signatures. In the progression-related profiles, 27 miRNAs were selected for pathologic T and 9 for lymph node involvement. In the survival analyses, the expression levels of mir-191, mir-19a, mir-210, and mir-425 were significantly associated with both recurrence-free survival (RFS) and overall survival, while mir-210 was proven as an independent prognostic factor in terms of RFS. In summary, miRNAs are expressed differentially in chRCC, and unique expression of miRNAs is associated with the progression and prognosis of chRCC.

miR-210 mediates vagus nerve stimulation-induced antioxidant stress and anti-apoptosis reactions following cerebral ischemia/reperfusion injury in rats

Vagus nerve stimulation (VNS) exerts neuroprotective effects against cerebral ischemia/reperfusion (I/R) injury and modulates redox status, potentially through the activity of miR-210, an important microRNA that is regulated by hypoxia-inducible factor and Akt-dependent pathways. The aim of this study was to determine the mechanisms of VNS- and miR-210-mediated hypoxic tolerance. Male Sprague-Dawley rats were preconditioned with a miR-210 antagomir (A) or with an antagomir control (AC), followed by middle cerebral artery occlusion and VNS treatment. The animals were divided into eight groups: sham I/R, I/R, I/R+AC, I/R+A, sham I/R+VNS, I/R+VNS, I/R+VNS+AC, and I/R+VNS+A. Activation of the endogenous cholinergic a7 nicotinic acetylcholine receptor (a7nAchR) pathway was identified using double immunofluorescence staining. miR-210 expression was measured by PCR. Behavioral outcomes, infarct volume, and neuronal apoptosis were observed at 24 h following reperfusion. Markers of oxidative stress were detected using ELISA. Rats treated with VNS showed increased miR-210 expression as well as decreased apoptosis and antioxidant stress responses compared with the I/R group; these rats also showed increased p-Akt protein expression and significantly decreased levels of cleaved caspase 3 in the ischemic penumbra, as measured by western blot and immunofluorescence analyses, respectively. Strikingly, the beneficial effects of VNS were attenuated following miR-210 knockdown. In conclusion, our results indicate that miR-210 is a potential mediator of VNS-induced neuroprotection against I/R injury. Our study highlights the neuroprotective potential of VNS, which, to date, has been largely unexplored. Since approved by the FDA in 1997, vagus nerve stimulation (VNS) has proven to be a safe and effective treatment for refractory epilepsy and resistant depression. Recent studies have found that VNS also provided neuroprotective effects against ischemic injury in a rat stroke model. We showed that miR-210 played an important role in the antioxidant stress and anti-apoptosis responses induced by VNS. This is the first report showing the effects of VNS at the mRNA level. Therefore, VNS represents a promising candidate treatment for ischemic stroke patients. Schematic view of the role of miR210 mediated in the protective effects of the VNS on the acute cerebral ischemia. VNS acts to activate neuronal and astrocytes a7nAchR , inhibits the apoptosis and oxidant stress responses possibly associated with increased Akt phosphorylation and miR210 expression.

Altered levels of circulating miRNAs are associated Schistosoma japonicum infection in mice

Background

Dioecious flatworms of the genus Schistosoma causes schistosomiasis, which is a major public health problem in developing countries. Acquiring detailed knowledge of schistosome-host interactions may aid in the development of novel strategies for schistosomiasis control. MicroRNAs (miRNAs) are involved in processes such as development, cell proliferation, metabolism, and signal transduction. Circulating miRNAs not only serve as a novel class of biomarkers of many diseases but also regulate target gene expression in recipient cells, which are similar to hormones.

Methods

In the present study, we used miRNA microarrays to determine the profile of circulating miRNAs associated with S. japonicum infection of mice. The biological functions of the altered levels of miRNAs and their target genes were predicted using bioinformatics. Expression levels of selected miRNAs and their target genes were further analyzed by quantitative RT-PCR.

Results

Our study identified 294 and 189 miRNAs in infected mice that were expressed in two independent experiments at levels ≥ 2-fold higher or ≤ 0.5-fold lower, respectively, compared with uninfected mice. Thirty-six of the same miRNAs were detected in these analyses. Moreover, pathway analyses indicated that most of these miRNAs are putatively involved in signaling pathways associated with pathogenesis, such as Wnt and MAPK signaling. Further, we show an inverse correlation between the circulating levels of these miRNAs and their target genes, suggesting that changes in miRNA expression may cause aberrant expression of genes such as Creb1 and Caspase-3 in mice infected with S. japonicum.

Conclusions

Our study shows significant differences in the levels of circulating miRNAs between S. japonicum infected mice and uninfected mice. In particular, the altered levels of miR-706 and miR-134-5p were associated with altered levels of expression of the Caspase-3 and Creb1 genes, respectively, suggesting that circulating miRNAs may serve as important mediators of the pathology of hepatic schistosomiasis. Additionally, our results are expected to provide new insights for further understanding the mechanisms of schistosome-host interaction that may facilitate in the development of novel interventions for alleviating the symptom of S. japonicum infection as well as for preventing and treating schistosomiasis.

Electronic supplementary material

The online version of this article (doi:10.1186/s13071-015-0806-5) contains supplementary material, which is available to authorized users.

MicroRNAs in pulmonary arterial hypertension: pathogenesis, diagnosis and treatment

Pulmonary arterial hypertension (PAH) is a severe and increasingly prevalent disease, manifested by the maladaptation of pulmonary vasculature, which consequently leads to right heart failure and possibly even death. The development of PAH is characterized by specific functional as well as structural changes, primarily associated with the aberrant function of the pulmonary artery endothelial cells, smooth muscle cells, and vascular fibroblasts. MicroRNAs constitute a class of small ≈22-nucleotides-long non-coding RNAs that post-transcriptionally regulate gene expression and that may lead to significant cell proteome changes. While the involvement of miRNAs in the development of various diseases--especially cancer--has been reported, numerous miRNAs have also been associated with PAH onset, progression, or treatment responsiveness. This review focuses on the role of microRNAs in the development of PAH as well as on their potential use as biomarkers and therapeutic tools in both experimental PAH models and in humans. Special attention is given to the roles of miR-21, miR-27a, the miR-17-92 cluster, miR-124, miR-138, the miR-143/145 cluster, miR-150, miR-190, miR-204, miR-206, miR-210, miR-328, and the miR-424/503 cluster, specifically with the objective of providing greater insight into the pervasive roles of miRNAs in the pathogenesis of this deadly condition.

Analysis of MicroRNAs in sputum to improve computed tomography for lung cancer diagnosis

INTRODUCTION

Computed tomography (CT) plays a central role in lung cancer diagnosis. However, CT has relatively low specificity, presenting a challenge in clinical settings. We previously identified 12 microRNAs (miRNAs) whose expressions in tumor tissues were associated with lung cancer.

METHODS

Using quantitative reverse transcriptase polymerase chain reaction, we aimed to identify miRNA biomarkers in sputum that could complement CT for diagnosis of lung cancer.

RESULTS

In a training set consisting of 66 lung cancer patients and 68 cancer-free smokers, 10 of the 12 miRNAs were differentially expressed between the cases and controls (p ≤ 0.01). From the miRNAs, a logistic regression model was built on the basis of miR-31 and miR-210, both of which had the best prediction for lung cancer, producing an area under receiver operating characteristic curve of 0.83. Combined use of the two miRNAs yielded 65.2% sensitivity and 89.7% specificity, CT had 93.9% sensitivity and 83.8% specificity for lung cancer diagnosis. Notably, combined analysis of the miRNA biomarkers and CT produced a higher specificity than does CT used alone (91.2% versus 83.8%; p < 0.05). The diagnostic performance of the biomarkers was confirmed in a testing set comprising 64 lung cancer patients and 73 cancer-free smokers.

CONCLUSION

The sputum miRNA biomarkers might be useful in improving CT for diagnosis of lung cancer, but further independent validation on an external and prospective cohort of patients is required.

Knockdown of miR-210 decreases hypoxic glioma stem cells stemness and radioresistance

Glioma contains abundant hypoxic regions which provide niches to promote the maintenance and expansion of glioma stem cells (GSCs), which are resistant to conventional therapies and responsible for recurrence. Given the fact that miR-210 plays a vital role in cellular adaption to hypoxia and in stem cell survival and stemness maintenance, strategies correcting the aberrantly expressed miR-210 might open up a new therapeutic avenue to hypoxia GSCs. In the present study, to explore the possibility of miR-210 as an effective therapeutic target to hypoxic GSCs, we employed a lentiviral-mediated anti-sense miR-210 gene transfer technique to knockdown miR-210 expression and analyze phenotypic changes in hypoxic U87s and SHG44s cells. We found that hypoxia led to an increased HIF-2α mRNA expression and miR-210 expression in GSCs. Knockdown of miR-210 decreased neurosphere formation capacity, stem cell marker expression and cell viability, and induced differentiation and G0/G1 arrest in hypoxic GSCs by partially rescued Myc antagonist (MNT) protein expression. Knockdown of MNT could reverse the gene expression changes and the growth inhibition resulting from knockdown of miR-210 in hypoxic GSCs. Moreover, knockdown of miR-210 led to increased apoptotic rate and Caspase-3/7 activity and decreased invasive capacity, reactive oxygen species (ROS) and lactate production and radioresistance in hypoxic GSCs. These findings suggest that miR-210 might be a potential therapeutic target to eliminate GSCs located in hypoxic niches.

MicroRNA-382 induced by HIF-1α is an angiogenic miR targeting the tumor suppressor phosphatase and tensin homolog

Recent studies have revealed that microRNAs (miRs) play important roles in the regulation of angiogenesis. In this study, we have characterized miR-382 upregulation by hypoxia and the functional relevance of miR-382 in tumor angiogenesis. miRs induced by hypoxia in MKN1 human gastric cancer cells were investigated using miRNA microarrays. We selected miR-382 and found that the expression of miR-382 was regulated by HIF-1α. Conditioned media (CM) from MKN1 cells transfected with a miR-382 inhibitor (antagomiR-382) under hypoxic conditions significantly decreased vascular endothelial cell (EC) proliferation, migration and tube formation. Algorithmic programs (Target Scan, miRanda and cbio) predicted that phosphatase and tensin homolog (PTEN) is a target gene of miR-382. Deletion of miR382-binding sequences in the PTEN mRNA 3′-untranslated region (UTR) diminished the luciferase reporter activity. Subsequent study showed that the overexpression of miR-382 or antagomiR-382 down- or upregulated PTEN and its downstream target AKT/mTOR signaling pathway, indicating that PTEN is a functional target gene of miR-382. In addition, PTEN inhibited miR-382-induced in vitro and in vivo angiogenesis as well as VEGF secretion, and the inhibition of miR-382 expression reduced xenograft tumor growth and microvessel density in tumors. Taken together, these results suggest that miR-382 induced by hypoxia promotes angiogenesis and acts as an angiogenic oncogene by repressing PTEN.

Drug resistance-related miRNAs in hepatocellular cancer

Hepatocellular cancer is a hypervascular cancer characterized by rapid progression as well as resistance to chemotherapy. Drug resistance arises from the alteration of many molecules, including oncogenes, tumor suppressor genes and miRNAs. This review evaluates the advances of drug resistance-related miRNAs in hepatocellular cancer, and analyzes the value of them as prognostic biomarkers and therapeutic targets. This review also discusses the limitations of miRNA-based therapy, and envisages future developments toward the clinical applications of drug resistance-related miRNAs.

Elevated expression of miR-210 predicts poor survival of cancer patients: a systematic review and meta-analysis

BACKGROUND

MiRNAs are important regulators of different biological processes, including tumorigenesis. MiR-210 is a potential prognostic factor for survival in patients with cancer according to previous clinical researches. We conducted a systematic review and meta-analysis to summarize the significance of increased miR-210 expression in the prognosis of indicated cancers.

METHODOLOGY/PRINCIPAL FINDINGS

The present systematic review and meta-analysis of 16 researches included 1809 patients with 7 different types of cancers from 7 countries, and aimed to explore the association between miR-210 expression and the survival of cancer patients. Over-expression of miR-210 may predict poor overall survival (OS, HR = 1.33, 95% CI: 0.85-2.09, P = 0.210), but the effect was not significant. While the predictive effect on disease-free survival (DFS, HR = 1.89, 95% CI: 1.30-2.74, P = 0.001), progression-free survival (PFS, HR = 1.20, 95% CI: 1.05-1.38, P = 0.007) and relapse-free survival(RFS, HR = 4.42, 95% CI: 2.14-9.15, P = 0.000) for patients with breast cancer, primary head and neck squamous cell carcinoma (HNSCC), renal cancer, soft-tissue sarcoma, pediatric osteosarcoma, bladder cancer or glioblastoma was certain. Subgroup analysis showed the limited predictive effect of over-expressed miR-210 on breast cancer OS (HR = 1.63, 95% CI: 0.47-5.67, P = 0.443), breast cancer DFS (HR = 2.03, 95% CI: 0.90-4.57, P = 0.088), sarcoma OS (HR = 1.24, 95% CI: 0.20-7.89, P = 0.818) and renal cancer OS (HR = 1.16, 95% CI: 0.27-4.94, P = 0.842).

CONCLUSIONS/SIGNIFICANCE

This systematic review and meta-analysis suggests that miR-210 has a predictive effect on survival of patients with studied cancer types as indexed by disease-free survival, progression-free survival and relapse-free survival. While the predictive effect on overall survival, breast cancer overall survival, breast cancer disease-free survival, sarcoma overall survival and renal cancer overall survival was not statistically significant.

Interplay between DNA repair and inflammation, and the link to cancer

DNA damage and repair are linked to cancer. DNA damage that is induced endogenously or from exogenous sources has the potential to result in mutations and genomic instability if not properly repaired, eventually leading to cancer. Inflammation is also linked to cancer. Reactive oxygen and nitrogen species (RONs) produced by inflammatory cells at sites of infection can induce DNA damage. RONs can also amplify inflammatory responses, leading to increased DNA damage. Here, we focus on the links between DNA damage, repair, and inflammation, as they relate to cancer. We examine the interplay between chronic inflammation, DNA damage and repair and review recent findings in this rapidly emerging field, including the links between DNA damage and the innate immune system, and the roles of inflammation in altering the microbiome, which subsequently leads to the induction of DNA damage in the colon. Mouse models of defective DNA repair and inflammatory control are extensively reviewed, including treatment of mouse models with pathogens, which leads to DNA damage. The roles of microRNAs in regulating inflammation and DNA repair are discussed. Importantly, DNA repair and inflammation are linked in many important ways, and in some cases balance each other to maintain homeostasis. The failure to repair DNA damage or to control inflammatory responses has the potential to lead to cancer.

MicroRNA-210 overexpression predicts poorer prognosis in glioma patients

MicroRNA-210 (miR-210) levels are elevated in many tumor types, are frequently associated with hypoxia induction, and are correlated with poor prognosis in many solid tumors. miR-210 regulates cell growth, angiogenesis, invasion, and apoptosis of many human tumors. In this study, we investigated the clinical significance of miR-210 expression in common brain tumors, or human gliomas. Glioma samples and normal brain tissues were analyzed using real-time quantitative reverse transcriptase polymerase chain reaction to characterize the expression patterns of miR-210. The association of miR-210 expression with clinicopathological parameters and prognosis of glioma patients was statistically analyzed. Gliomas were further divided by grade: pilocytic astrocytoma (World Health Organization [WHO] grade I), diffuse astrocytomas (WHO grade II), anaplastic astrocytomas (WHO grade III), and glioblastoma (WHO grade IV). There was a significantly higher expression level of miR-210 amongst the glioma tissues as compared with normal brain tissues (p<0.001). Increased expression of miR-210 in glioma tissues was significantly associated with advanced pathological grade (p<0.001) and low Karnofsky Performance Score (p=0.014). In addition, increased miR-210 levels were also associated with poor progression-free survival (PFS) and overall survival (OS) rates when compared to the normal control (both p<0.001), as calculated by Kaplan-Meier survival and Cox regression analyses. Furthermore, subgroup analyses showed that miR-210 expression was significantly associated with poor PFS and OS of glioma patients with high pathological grades (III-IV: both p<0.001). miR-210 is highly expressed in human gliomas and confers a poor prognosis in glioma patients. These findings may bring the development of novel, tailored pharmacological therapies for glioma patients.

MicroRNA-21: a therapeutic target for reversing drug resistance in cancer

INTRODUCTION

Drug resistance is a major clinical obstacle to the successful treatment of human cancer. The microRNAs-21 (miR-21), an oncomiR, may play an important role in the progress of drug resistance.

AREAS COVERED

This review covers all related literature on miR-21 in drug resistance of human cancers and analyzes the expression, biological functions and targets of it. This study also envisages future developments toward its clinical and therapeutic applications in cancer treatment.

EXPERT OPINION

The miR-21 may promote the drug resistance of various cancers. Inhibitors of miR-21 may function as effective approaches for reversing drug resistance in cancer cells. There is a tough way from discovering the function of miR-21 to clinical use. Further understanding of miR-21-mediated signaling pathways will help to promote the therapeutic-clinical use of miR-21 in cancer.