miR-18a expression correlates with ATM and p53 levels and poor prognosis in lymphomas

microRNAs (miRNAs) are non-coding, endogenous, small-molecule RNAs. They are involved in cell proliferation, differentiation, apoptosis, and metabolism. Additionally, they play an essential role in the development and progression of various malignancies. Recent research has revealed that miR-18a plays an important role in cancer development. However, its role in lymphoma is not yet fully understood. In this study, we investigated the clinicopathological characteristics and potential functional roles of miR-18a in lymphomas. First, we predicted the potential downstream genes of miR-18a using miRTarBase software and subjected these downstream genes to Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses to determine the potential mechanisms of action of these genes. We found that these target genes were closely related to cellular senescence, the p53 signaling pathway, and other signaling pathways. From the predicted downstream target genes, ATM and p53 were selected as the target genes; their deletion in patients with lymphoma was detected using the fluorescence in situ hybridization technique. The results showed that some patients with lymphoma have a deletion of the ATM and p53 genes. In addition, the deletion rates of ATM and p53 were positively correlated with the expression of miR-18a. Next, the expression levels of miR-18a and the deletion rates of ATM and p53 were used for correlation and prognostic analyses with patient clinical information. The findings revealed a significant difference in disease-free survival (DFS) between patients with lymphoma with ATM deletion and those with a normal ATM gene expression (p < 0.001). Moreover, a significant difference in overall survival (OS) and DFS between patients with p53 deletion and those with normal p53 expression was observed (p < 0.001). The results indicate that the deletion of ATM and p53 downstream of miR-18a is closely associated with the development of lymphoma. Thus, these biomarkers may serve as key prognostic biomarkers for lymphomas.

Epigenetics in Canine Mammary Tumors: Upregulation of miR-18a and miR-18b Oncogenes Is Associated with Decreased ERS1 Target mRNA Expression and ERα Immunoexpression in Highly Proliferating Carcinomas

The expression of miRNAs is one of the main epigenetic mechanisms responsible for the regulation of gene expression in mammals, and in cancer, miRNAs participate by regulating the expression of protein-coding cancer-associated genes. In canine mammary tumors (CMTs), the ESR1 gene encodes for ERα, and represents a major target gene for miR-18a and miR-18b, previously found to be overexpressed in mammary carcinomas. A loss in ERα expression in CMTs is commonly associated with poor prognosis, and it is noteworthy that the downregulation of the ESR1 would appear to be more epigenetic than genetic in nature. In this study, the expression of ESR1 mRNA in formalin-fixed, paraffin-embedded (FFPE) canine mammary tumors (CMTs) was evaluated and compared with the expression levels of miR18a and miR18b, both assessed via RT-qPCR. Furthermore, the possible correlation between the miRNA expression data and the immunohistochemical prognostic factors (ERα immunoexpression; Ki67 proliferative index) was explored. A total of twenty-six FFPE mammary samples were used, including 22 CMTs (7 benign; 15 malignant) and four control samples (three normal mammary glands and one case of lobular hyperplasia). The obtained results demonstrate that miR-18a and miR-18b are upregulated in malignant CMTs, negatively correlating with the expression of target ESR1 mRNA. Of note, the upregulation of miRNAs strictly reflects the progressive loss of ERα immunoexpression and increased tumor cell proliferation as measured using the Ki67 index. The results suggest a central role of miR-18a and miR-18b in the pathophysiology of canine mammary tumors as potential epigenetic mechanisms involved in ERα downregulation. Moreover, as miRNA expression reflects ERα protein status and a high proliferative index, miR-18a and miR-18b may represent promising biomarkers with prognostic value. More detailed investigations on a larger number of cases are needed to better understand the influence of these miRNAs in canine mammary tumors.

Long noncoding RNA CASC2 protect ROS-induced oxidative stress in myocardial infarction by miR-18a/SIRT2

We aimed to investigate the function and its possible mechanisms of long noncoding RNA (lncRNA) in acute myocardial infarction (AMI) model. Patients with AMI and normal volunteers were selected from our hospital. Sprague-Dawley rats were induced into in vivo model of AMI. H9c2 cells were treated with H₂ O₂ to generate injury model. A significantly lower serum gene expression of lncRNA CASC2 was detected. In rat models of AMI, lncRNA CASC2 gene expressions in heart tissue of mice with AMI were decreased. In in vitro model, downregulation of lncRNA CASC2 increased reactive oxygen species (ROS)-induced oxidative stress; lncRNA CASC2 induced NADPH oxidase (NOX-2) expression and suppressed miR-18a expression; MiR-18a promoted ROS-induced oxidative stress; downregulation of miR-18a decreased ROS-induced oxidative stress. The inhibition of miR-18a reversed the effects of CASC2 downregulation on ROS-induced oxidative stress in in vitro model of AMI. The activation of miR-18a reversed the effects of CASC2 on ROS-induced oxidative stress in in vitro model of AMI. These data for the first time suggest that lncRNA CASC2 have better protective effects on AMI, which could reduce oxidative stress through their carried miR-18a and subsequently downregulating the SIRT2/ROS pathway.

Expression of miR-221 and miR-18a in patients with hepatocellular carcinoma and its clinical significance

Purpose

Recently, microRNA (miRNA) has been evaluated to provide a new diagnostic and therapeutic modality hepatocellular carcinoma (HCC) and other tumors. They are small non-coding RNA molecules that function as transcriptional and post-transcriptional regulators of gene expression by silencing target genes. The aim of this study was to evaluate the clinical significance of microRNA-18a, 221 (miR-18a, miR-221) expression in HCC formalin-fixed paraffin-embedded (FFPE) tissue.

Methods

miR-18a and miR-221 expressions were assessed by reverse transcription and real-time quantitative reverse transcription polymerase chain reaction in 50 pairs of FFPE HCC and the adjacent noncancerous liver tissues. And we evaluated the expression level in HCC tissues as compared with their adjacent noncancerous counterparts. And the relationship between miR-18a, miR-221 level and clinicopathological data and survival rates were analyzed.

Results

miR-221 and miR-18a were overexpressed in HCC tissue as compared with their adjacent noncancerous liver tissue (P<0.001). miR-221 expression was found to be correlated with larger tumor size (P=0.048). miR-18a expression was correlated with modified Union for International Cancer Control stage (P=0.05). The overall survival (P=0.02) of HCC patients with high miR-221 expression was significantly poorer compared to those patients with low expression. Multivariate analyses demonstrated that miR-221 may be a poor prognostic factor of HCC patients.

Conclusion

High expression of miR-221 in FFPE tissues could provide significance for prognosis of HCC patients. Although, miR-18a expression was significantly upregulated in HCC tissues, they are not correlated with prognosis. Further large prospective studies are needed to determine their clinical significance.

miR-18a Mediates Immune Evasion in ER-Positive Breast Cancer through Wnt Signaling

ER-positive (ER+) breast cancer is considered immunologically ‘silent’ with fewer tumor-infiltrating immune cells. We have previously demonstrated the role of miR-18a in mediating invasion and poor prognosis in ER+ breast cancer by activation of the Wnt signaling pathway. Here, we explored the immune-modulatory functions of high levels of miR-18a in these tumors. A microarray-based gene expression analysis performed in miR-18a over-expressed ER+ breast cancer cell lines demonstrated dysregulation and suppression of immune-related pathways. Stratification of the ER+ tumor samples by miR-18a levels in the TCGA and METABRIC cohort and immune cell identification performed using CIBERSORT and Immune CellAI algorithms revealed a higher proportion of T-regulatory cells (p < 0.001) and a higher CD4/CD8 ratio (p < 0.01). miR-18a over-expressed MCF7 co-cultured with THP-1 showed decreased antigen presentation abilities and increased invasiveness and survival. They also promoted the differentiation of pro-tumorigenic M2 macrophages. Inhibition of the Wnt pathway in miR-18a over-expressed cells brought about the restoration of TAP-1, a protein critical for antigen presentation. Examination of tumor specimens from our case series showed that miR-18a high ER+ tumors had a dense lymphocyte infiltrate when compared to miR-18a low tumors but expressed a higher CD4/CD8 ratio and the M2 macrophage marker CD206, along with the invasive marker MMP9. We report for the first time an association between miR-18a-mediated Wnt signaling and stromal immune modulation in ER+ tumors. Our results highlight the possibility of formulating specific Wnt pathway inhibitors that may be used in combination with immune checkpoint blockers (ICB) for sensitizing ‘immune-cold’ ER+ tumors to immunotherapy.

Downregulated miR-18a and miR-92a synergistically suppress non-small cell lung cancer via targeting Sprouty 4

As a novel noncoding RNA cluster, miR-17-92 cluster include six members: miR-17, miR-18a, miR-19a, miR-19b-1, miR-20a, and miR-92a. Dysregulation of miR-17-92 has been proved to be connected with the advancement of a series of human diseases, but the roles of miR-17-92 cluster in non-small cell lung cancer (NSCLC) have not been absolutely elaborated. Herein, we determined that miR-17-92 cluster were upregulated significantly in NSCLC tissues, and the cell proliferation, migration and cycle progression of NSCLC were also facilitated under the function of miR-17-92 cluster. Sprouty 4 (SPRY4) was a direct target of miR-92a, and its overexpression restrained the exacerbation of NSCLC induced by miR-92a. Furthermore, the tumor xenograft assay showed that miR-92a facilitated tumor growth by inhibiting the expression of SPRY4 and mediating Epithelial-Mesenchymal Transition (EMT) in vivo. Finally, we looked into the synergistic effects of miR-92a and miR-18a on NSCLC, and found that antagomiR-18a treatment arrested the tumor growth rate of xenografted mice markedly.

STAT1 mediates the PI3K/AKT pathway through promoting microRNA-18a in nasal polyps

BACKGROUND

Epithelial to mesenchymal transition (EMT) is linked to the pathophysiology of chronic rhinosinusitis with nasal polyps (CRSwNP). The involvement of STAT1 has been reported in CRSwNP. However, its specific role in regulating EMT in CRSwNP is not clear. We sought to evaluate the role of STAT1 in EMT in CRSwNP using clinical samples and a murine model.

METHODS

Comprehensive analysis of differentially expressed genes was performed in nasal polyps from the CRSwNP patients, followed by pathway enrichment analysis. After bioinformatics prediction, the relationships between microRNA-18a (miR-18a) and PTEN or STAT1 were examined using dual-luciferase and RIP assays, respectively. The expression of STAT1, PTEN, and miR-18a in nasal tissues was detected using RT-qPCR, immunohistochemistry, and in situ hybridization. After the alteration of gene expression in mice with CRSwNP, western blot, RT-qPCR, and HE staining were conducted to detect EMT-related proteins, inflammatory factor secretion, inflammatory cell infiltration, and the PI3K/AKT pathway activity in nasal tissues.

RESULTS

STAT1 and miR-18a were highly expressed, and PTEN was poorly expressed in the nasal polyp. STAT1 promoted transcription of miR-18a, which targeted PTEN. Downregulation of STAT1 and miR-18a inhibited the EMT and inflammatory cell infiltration, while depletion of PTEN promoted the EMT and inflammatory cell infiltration in the nasal polyp. The PI3K/AKT pathway was activated in the nasal polyp and regulated by the STAT1/miR-18a/PTEN axis.

CONCLUSIONS

STAT1 acts as a transcription factor to promote transcription of miR-18a, and miR-18a targets PTEN to exacerbate the inflammatory response and EMT in CRSwNP.

The UCA1 and microRNA-18a signaling pathway mediates the irisin-lowering effect of metformin in the management of polycystic ovary syndrome

INTRODUCTION

The present study aimed to clarify the underlying mechanism of metformin (met) in the management of polycystic ovary syndrome (PCOS) and to explore the role of the UCA1/microRNA-18a signaling pathway in the control of PCOS.

MATERIAL AND METHODS

Real-time PCR was performed to compare the levels of irisin, blood glucose, UCA1 and miR-18a among PCOS, PCOS + Met, and control groups using area under curve (AUC) values. In-silicon analysis and luciferase assay were performed to explore the regulatory relationship among UCA1, miR-18a and irisin. Real-time PCR and Western blot analysis were carried out to detect the effect of met on the expression of UCA1, miR-18a and irisin.

RESULTS

AUC of UCA1 was the highest while AUC of irisin was the lowest. Also, irisin and UCA1 levels in the PCOS group were much higher than those in the PCOS + Met group, while miR-18a level in the PCOS group was much lower than in the PCOS + Met group. Through the luciferase assay, miR-18a was proved to directly bind to the irisin 3'UTR. Additionally, irisin was identified to be a target gene of miR-18a. Finally, treatment with met at an increasing concentration reduced the level of UCA1 and irisin but increased the level of miR-18a in a dose-dependent manner.

CONCLUSIONS

In the management of PCOS, the irisin-lowering effect of met is regulated by the UCA1/miR-18a/RhoB signaling pathway.

Usnic Acid Inhibits Proliferation and Migration through ATM Mediated DNA Damage Response in RKO Colorectal Cancer Cell

BACKGROUND

Usnic Acid (UA), also known as lichenol, has been reported to have inhibitory effects on a variety of cancer cells, but its specific mechanism remained to be elucidated. Tumor chemotherapy drugs, especially DNA damage chemotherapeutic drugs, target Chromosomal DNA, but their spontaneous and acquired drug resistance are also an urgent problem to be solved. Therefore, drug combination research has become the focus of researchers.

METHODS

Here, we evaluated the tumor-suppressing molecular mechanism of UA in colorectal cancer cells RKO from the perspective of the ATM-mediated DNA damage signaling pathway through H2O2 simulating DNA damage chemotherapeutic drugs. CCK8 cell proliferation assay was used to determine the inhibition of RKO cells by hydrogen peroxide and UA alone or in combination, and wound healing assay was applied to determine the effect of the drug on cell migration.

RESULTS

Transfected cells with miRNA18a-5p mimics and inhibitors, MDC and DCFH-DA staining for the measurement of autophagy and ROS, cell cycle and apoptosis were detected by flow cytometry, expressions of microRNA and mRNA were determined by fluorescence quantitative PCR, and protein by Western blot.

DISCUSSION

We found that UA can upregulate ATM via miR-18a to activate the DNA damage signaling pathway and inhibit the proliferation and migration of RKO cells in a concentration-dependent manner.

CONCLUSION

At the same time, DNA damage responses, including cell cycle, autophagy, apoptosis and ROS levels, are also regulated by UA. Therefore, UA combined with DNA damage chemotherapeutic drugs may be an effective treatment for cancer.

Circular RNA circRHOBTB3 is downregulated in hepatocellular carcinoma and suppresses cell proliferation by inhibiting miR-18a maturation

BACKGROUND

Circular RNA circRHOBTB3 has been characterized as a tumor suppressor in gastric cancer, while its role in hepatocellular carcinoma (HCC) is unknown. This study was carried out to analyze the role of circRHOBTB3 in HCC.

METHODS

In this study, circRHOBTB3, mature miR-18a, and miR-18a precursor in HCC and paired non-cancer tissues were detected by RT-qPCR. The role of circRHOBTB3 in the production of mature miR-18a was explored by transfecting circRHOBTB3 expression vector into HCC cells, followed by RT-qPCR to determine the expression of mature miR-18a and miR-18a precursor. The role of circRHOBTB3 and miR-18a in HCC cell proliferation was studied using CCK-8 assay.

RESULTS

CircRHOBTB3 was under-expressed in HCC compared to normal tissues. In HCC cells, circRHOBTB3 overexpression decreased mature miR-18a level but not miR-18a precursor. Cell proliferation analysis showed that circRHOBTB3 overexpression decreased cell proliferation while miR-18a overexpression increased cell proliferation. Moreover, circRHOBTB3 suppressed the role of miR-18a in cell proliferation.

CONCLUSIONS

CircRHOBTB3 is downregulated in HCC and may suppress cell proliferation by reducing miR-18a production.

Altered miR-93-5p/miR-18a expression in serum for diagnosing non-small cell lung cancer

OBJECTIVE

This research aimed at probing into miR-93-5p and miR-18a's diagnostic and prognostic values in non-small cell lung cancer (NSCLC) patients.

METHODS

A total of 107 patients diagnosed with NSCLC in the Department of Oncology and Thoracic Surgery of our hospital from January 2015 to June 2016 were regarded as the research group (RG), and 42 healthy people were considered as the control group (CG). Serum samples were collected and miR-93-5p, miR-18a expression was detected via qPCR. The relationship between miR-93-5p, miR-18a and clinicopathological characteristics of NSCLC patients was assessed, and the diagnostic value of the two miRNAs was analyzed by ROC curve.

RESULTS

miR-93-5p and miR-18a were up-regulated in NSCLC. The higher the degree of tumor differentiation, the higher the TNM stage and the expression of the two miRNAs were. The high expression was tied to tumor differentiation degree, TNM stage, lymph node metastasis and lymph-vascular space invasion (LVSI). The survival rate of miR-93-5p and miR-18a high expression patients was worse than that of those with low expression. The AUC value of both of the mRNAs in NSCLC diagnosis was high (0.8905).

CONCLUSION

The expression of miR-93-5p and miR-18a is associated with NSCLC severity and prognosis, and both can be used as potential markers for diagnosis.

MicroRNA-18a-5p Suppresses Tumor Growth via Targeting Matrix Metalloproteinase-3 in Cisplatin-Resistant Ovarian Cancer

Cumulating evidence indicates that dysregulation of microRNAs (miRNAs) plays a central role in the initiation, progression, and drug resistance of cancer cells. However, the specific miRNAs contributing to drug resistance in ovarian cancer cells have not been fully elucidated. Aimed to identify potential miRNAs involved in platinum resistance, we performed a miRNA expression profile in cisplatin-sensitive and cisplatin-resistant ovarian cancer cells, and we found several differentially abundant miRNAs in the pair of cell lines. Notably, miR-18a-5p (miR-18a), a member of the oncogenic associated miR-17-92 cluster, was decreased in cisplatin-resistant as compared with cisplatin-sensitive cells. Real-time PCR analysis confirmed these findings. We then studied the biological, molecular, and therapeutic consequences of increasing the miR-18a levels with oligonucleotide microRNA mimics (OMM). Compared with a negative control OMM, transient transfection of a miR-18a-OMM reduced cell growth, cell proliferation, and cell invasion. Intraperitoneal injections of miR-18a-OMM-loaded folate-conjugated liposomes significantly reduced the tumor weight and the number of nodules in ovarian cancer-bearing mice when compared with a control-OMM group. Survival analysis using the Kaplan-Meier plotter database showed that ovarian cancer patients with high miR-18a levels live longer in comparison to patients with lower miR-18a levels. Bioinformatic analyses, real-time-PCR, Western blots, and luciferase reporter assays revealed that Matrix Metalloproteinase-3 (MMP-3) is a direct target of miR-18a. Small-interfering RNA (siRNA)-mediated silencing of MMP-3 reduced cell viability, cell growth, and the invasiveness potential of cisplatin-resistant ovarian cancer cells. Our study suggests that targeting miR-18a is a plausible therapeutic strategy for cisplatin-resistant ovarian cancer.

miR-18a increases insulin sensitivity by inhibiting PTEN

The miR-17-92 cluster (miR-17, miR-18a, miR-19a, miR-20a, miR-19b-1 and miR-92a) contributes to the occurrence and development of various diseases by inhibiting multiple target genes. Here, we explored the effects of miR-18a on insulin sensitivity. Quantitative real-time PCR indicated that serum miR-18a levels were lower in type 2 diabetes mellitus patients than in healthy controls, suggesting that miR-18a may influence blood glucose levels. Global overexpression of miR-18a in transgenic mice increased their glucose tolerance and insulin sensitivity, while it reduced expression of the phosphatase and tensin homolog deleted on chromosome ten (PTEN) in their skeletal muscle and adipose tissue. Western blotting indicated that overexpressing miR-18a in 3T3-L1 and C2C12 cells enhanced insulin-stimulated AKT phosphorylation and suppressed PTEN expression, while inhibiting miR-18a had the opposite effects. These results suggest that miR-18a improves insulin sensitivity by downregulating PTEN. This makes miR-18a a potentially useful target for the treatment of diabetes mellitus in the future.

miR-18a Contributes to Preeclampsia by Downregulating Smad2 (Full Length) and Reducing TGF-β Signaling

The study investigated the regulation of Smad2 by miR-18a and its role in preeclampsia (PE). Bioinformatics analysis showed that both Smad2 and Smad3 were the predicted targets for miR-18a. Mass spectrum analysis showed that two mature Smad2 isoforms existed in human placenta: full length, Smad2(FL), and that lacking exon3, Smad2(Δexon3). The protein level of Smad2(FL), but not Smad2(Δexon3) or Smad3, was significantly increased in severe PE (sPE) placenta, which was inversely correlated with the level of miR-18a. Elevated Smad2(FL) phosphorylation level appeared in sPE placenta, and Smad2 was colocalized with miR-18a in various subtypes of trophoblasts in human placenta. Smad2(FL) was validated as the direct target of miR-18a in HTR8/SVneo cells. miR-18a enhanced trophoblast cell invasion, which was blocked by the overexpression of Smad2(FL). Furthermore, overexpression of miR-18a repressed Smad2 activation and the inhibition of trophoblast cell invasion by transforming growth factor-β (TGF-β). In conclusion, our results suggest that miR-18a inhibits the expression of Smad2(FL), but not Smad2(Δexon3) or Smad3, which can reduce TGF-β signaling, leading to the enhancement of trophoblast cell invasion. A lack of miR-18a, which results in the upregulation of Smad2(FL), contributes to the development of PE.

Good or not good: Role of miR-18a in cancer biology

miR-18a is a member of primary transcript called miR-17-92a (C13orf25 or MIR17HG) which also contains five other miRNAs: miR-17, miR-19a, miR-20a, miR-19b and miR-92a. This cluster as a whole shows specific characteristics, where miR-18a seems to be unique. In contrast to the other members, the expression of miR-18a is additionally controlled and probably functions as its own internal controller of the cluster. miR-18a regulates many genes involved in proliferation, cell cycle, apoptosis, response to different kinds of stress, autophagy and differentiation. The disturbances of miR-18a expression are observed in cancer as well as in different diseases or pathological states. The miR-17-92a cluster is commonly described as oncogenic and it is known as 'oncomiR-1', but this statement is a simplification because miR-18a can act both as an oncogene and a suppressor. In this review we summarize the current knowledge about miR-18a focusing on its regulation, role in cancer biology and utility as a potential biomarker.

Cortical Bone Derived Stem Cells Modulate Cardiac Fibroblast Response via miR-18a in the Heart After Injury

The adult heart following injury such as a myocardial infarction forms a fibrotic scar associated with transformation of resident cardiac fibroblasts into myofibroblast, accelerating cardiac remodeling and dysfunction. Cell therapies provide a novel direction for the enhancement of cardiac structure and function but remain poorly described in terms of the effect on resident cardiac fibroblasts. We have shown cortical bone derived stem cells (CBSCs) exhibit an ability to repair the heart after myocardial injury together with reduced scar formation. Nevertheless, whether CBSCs possess ability to modulate resident fibroblast response after myocardial injury remains untested.

miR-18a activates Wnt pathway in ER-positive breast cancer and is associated with poor prognosis

Despite the established benefits of long‐term endocrine therapy, women with hormone receptor‐positive breast cancer remain at risk for late relapse. The basis of this is multi‐factorial including genetic, epigenetic, and host factors. In this study we have explored the epigenetic regulation of estrogen receptor (ER)‐dependent molecular and cellular phenotype by hsa‐miR‐18a‐5p using well‐established human ER‐positive (ER+) breast cancer cell lines. miR‐18a was overexpressed in MCF7 and ZR‐75‐1 and this led to an increase in the proliferative ability of the cells and concurrently resulted in decreased expression of luminal markers and higher expression of the basal marker, cytokeratin 14. The cells became more migratory with a significant repression of E‐cadherin and activation of the Wnt noncanonical pathway. We observed an activation of the planar cell polarity (PCP) pathway with increased activation of JNK pathway and eventually change in actin dynamics. There was increased F‐actin polymerization in cells with higher expression of miR‐18a. Examination of miR‐18a expression in a set of human ER+ breast cancer specimens showed a negative correlation between miR‐18a and ESR1 transcripts as well as ER protein. Kaplan‐Meier survival analysis of the cohort stratified by tumor hsa‐miR‐18a‐5p levels produced significant differences in disease‐free survival (log rank P < .05). This observation was independently validated in the METABRIC cohort. These data provide support for a role of hsa‐miR‐18a‐5p in altering the proliferative and migratory behavior of ER+ cells and its potential utility as a prognostic marker in clinical ER+ breast cancers.

The Effect of (E)-1-(4'-aminophenyl)-3-phenylprop-2-en-1-one on MicroRNA-18a, Dicer1, and MMP-9 Expressions against DMBA-Induced Breast Cancer

BACKGROUND

Most of breast cancer patients are estrogen receptor alpha-positive and have high resistance and side effect of chemotherapeutic drug. Therefore, discovering an effective anticancer agent is needed. This research explored the effect of (E)-1-(4'-aminophenyl)-3-phenylprop-2-en-1-one (APE) on miR-18a, Dicer1, and MMP-9 expressions.

METHODS

Twenty four female Sprague-Dawley rats were invetigated in this study. The rats were divided into 6 groups of 4. G1 was considered as normal rat. G2, G3, T1, T2, and T3 were given DMBA 20 mg/kgBW twice a week for 5 weeks to induce mammary cancer. After being affiliated with cancer, G2 was given vehicle and G3 was treated with tamoxifen. T1, T2, and T3 were treated with APE intraperitoneally everyday for 21 days at doses of 5, 15, and 45 mg/kgBW/day, respectively. Blood plasma was collected to measure miR-18a expression using qRT-PCR. Mammary tissues were also collected to determine Dicer1 and MMP-9 expressions by using  immunohistochemistry.

RESULTS

The results showed significant down-regulation of miR-18a relative expression and up-regulation of Dicer1 expression in G3 and T1 compared to G2 (P<0.05). MMP-9 expression has significant decrease in T1 compared to G2 (P<0.05).

CONCLUSION

APE can decrease miR-18a and MMP-9 expressions and increase Dicer1 expression in rat mammary cancer. Therefore, this compound could be a candidate of novel anticancer.

Role of miR-18a and miR-25 disruption and its mechanistic pattern in progression of liver cancer

This study examined the molecular mechanisms underlying the roles of the microRNAs miR-18a and miR-25 in the progression of human liver cancer. Liver cancer biopsies obtained from early-stage liver cancer patients were examined by qRT-PCR and Northern blotting to examine the expression of miR-18a and miR-25. Both microRNAs were overexpressed in mouse primary hepatocytes following transfection of the cells with vectors encoding the microRNAs. An analysis of biopsy samples from liver cancer patients indicated that both miR-18a and miR-25 were overexpressed during the early stages of liver cancer. Further, qRT-PCR and Northern blotting confirmed that both of these microRNAs play crucial roles in the progression of liver cancer. Our findings clearly indicate that miR-18a and miR-25 can be used as prognostic biomarkers for early-stage liver cancer. Hence, miR-18a and miR-25 may have value as prognostic indicators and may facilitate the development of novel therapeutics for liver cancer.

miR-18a promotes Mycobacterial survival in macrophages via inhibiting autophagy by down-regulation of ATM

Tuberculosis (TB), caused by Mycobacterium tuberculosis (Mtb), is one of leading causes of global deaths. This study aimed to explore the role of miR-18a in RAW264.7 cells response to Mtb infection. Exosomes derived from Mtb-infected cells were isolated and further validated by size, transmission electron microscopy and Western blot. RT-PCR was utilized to measure miR-18a expression. Cell viability and ultrastructure were examined by CFU counting, CCK-8 and electron microscope, respectively. Potential target genes of miR-18a were predicted with bioinformatics and further confirmed using RT-PCR, Western blot and laser confocal microscope analysis, respectively. LC3, AMPK and mTOR were measured using Western blot. We found that miR-18a was induced both in Mtb-infected RAW264.7 cells and its derived exosomes compared with the controls. In addition, up-regulation of miR-18a promoted intracellular Mtb survival, attenuated cell viability and reduced LC3-II level, while its down-regulation had the opposite effect. miR-18a overexpression suppressed level of ATM, one possible target of miR-18a, while its underexpression enhanced ATM. We also found that inhibition of ATM induced LC3-II decrease in Mtb-infected cells and could reverse the increase of LC3-II caused by inhibition of miR-18a. Moreover, down-regulation of miR-18a increased p-AMPK level while reduction of ATM could reverse the change. Taken together, our results suggest that miR-18a is up-regulated in macrophages response to Mtb infection, and it promotes intracellular Mtb survival through repressing autophagic process by down-regulation of ATM pathway. This provides new thought for TB pathogenesis, diagnosis and treatment.

Long noncoding RNA GAS5 modulates α-Solanine-induced radiosensitivity by negatively regulating miR-18a in human prostate cancer cells

Radiotherapy is an adjuvant treatment of surgery in prostate cancer, while radioresistance has been the challenge of treatment. It has been reported that α-Solanine exhibits anti-cancer activity and enhances the chemo- and radio-sensitivity in several human cancers, whereas the role of α-Solanine on radiosensitivity to PCa remains to be uncovered yet. We found α-Solanine decreased cell viability in human PCa cells rather than normal prostate epithelial cells in vitro. Functional experiments showed that cell viability and colonies formation were declined & apoptosis rate and DNA double strand breaks (DSBs) marker γ-H2AX expressions were elevated by α-Solanine in PCa cells treated with X-ray irradiation, compared with X-ray irradiation treatment only. GAS5 was down-regulated & miR-18a was up-regulated in PCa cells, which was reversed in the presence of α-Solanine. Effects of ectopic GAS5 on inhibiting cell viability and survival & promoting apoptosis and DNA damage were reversed by miR-18a overexpression in PCa cells. Moreover, GAS5 regulated miR-18a expression by target binding during α-Solanine treatment. Collectively, α-Solanine suppresses cell proliferation and promotes radiosensitivity through up-regulating GAS5/miR-18a pathway in PCa. Our results provide a novel mechanism of α-Solanine treatment in human prostate cancer and help to develop a new approach to sensitizing radioresistant prostate cancer cells by targeting GAS5/miR-18a.

[The expressions and diagnostic values of miR-18a and miR-21 in esophageal cancer]

Objective: To investigate the expressional levels and diagnostic values of miR-18a and miR-21 in esophageal carcinoma. Methods: The expressions of miR-18a and miR-21 in esophageal cancer tissues and adjacent tissues from 45 esophageal cancer patients, peripheral blood from 45 esophageal cancer patients and 50 healthy donors respectively were detected by RT-PCR. The expressions of miR-18a and miR-21 in normal esophageal epithelial cell HET-1A, esophageal cancer cell lines including ECA109, KYSE150 and TE1 were also detected. Chemiluminescence immunoassay was used to quantitatively detect the concentrations of carcinoembryonic antigen (CEA), squamous cell carcinoma antigen (SCC), CYRFA21-1 and TPA (tissue polypeptide antigen) in peripheral blood serum from esophageal cancer patients and healthy controls. Meanwhile, the diagnostic effects of miR-18a and miR-21 on esophageal cancer were compared with those of tumor markers in serum. Results: The expression levels of miR-18a and miR-21 in esophageal cancer cells ECA109, KYSE150 and TE1 were 1.64±0.17, 1.62±0.19, 1.46±0.12 and 20.52±1.48, 6.73±0.73, 1.43±0.19, respectively, higher than those in normal esophageal epithelial cells (both P<0.01). The expressions of miR-18a and miR-21 in esophageal cancer tissues were 32.48±28.62 and 8.67±11.98, respectively, significantly higher than those in adjacent tissues (all P<0.001). The expression levels of miR-18a and miR-21 in peripheral blood of patients with esophageal cancer were 12.66±11.92 and 9.15±8.14, respectively, significantly higher than those in the normal control group (both P<0.001). The receiver operating characteristic (ROC) curve analysis showed that the area under the curve of miR-18a and miR-21 for diagnosis of esophageal cancer were 0.948 and 0.913 5, respectively. Compared with traditional esophageal tumor markers, the expressions of miR-18a and miR-21 were more sensitive in the diagnosis of esophageal cancer. The sensitivity and accuracy of the expressions of miR-18a and miR-21 combined with traditional esophageal tumor markers in diagnosis of esophageal cancer can be further improved to 97.8% and 68.4%, respectively. Conclusion: Our study reveals that the expressions of miR-18a and miR-21 play important roles in the diagnosis of esophageal cancer and may be potentially novel biomarkers.

miR-18a reactivates the Epstein-Barr virus through defective DNA damage response and promotes genomic instability in EBV-associated lymphomas

Background

The Epstein-Barr virus (EBV) is closely associated with several types of malignancies. EBV is normally present in the latent state in the peripheral blood B cell compartment. The EBV latent-to-lytic switch is required for virus spread and virus-induced carinogenesis. Immunosuppression or DNA damage can induce the reactivation of EBV replication. EBV alone is rarely sufficient to cause cancer. In this study, we investigated the roles of host microRNAs and environmental factors, such as DNA-damage agents, in EBV reactivation and its association with lymphomagenesis.

Methods

We first analyzed the publicly available microRNA array data containing 45 diffuse large B-cell lymphoma patients and 10 control lymph nodes or B cells with or without EBV infection. In situ hybridization for miR-18a and immunohistochemitry were performed to evaluate the correlation between the expression of miR-18a and nuclear EBV protein EBNA1 in lymphoid neoplasm. The proliferative effects of miR-18a were investigated in EBV-positive or –negative lymphoid neoplasm cell lines. EBV viral load was measured by a quantitative real-time EBV PCR and FISH assay. The genomic instability was evaluated by CGH-array.

Results

In this study, we analyzed the publicly available microRNA array data and observed that the expression of the miR-17-92 cluster was associated with EBV status. In situ hybridization for miR-18a, which is a member of the miR-17-92 cluster, showed a significant upregulation in lymphoma samples. miR-18a, which shares the homolog sequence with EBV-encoded BART-5, promoted the proliferation of lymphoma cells in an EBV status-dependent manner. The DNA-damaging agent UV or hypoxia stress induced EBV activation, and miR-18a contributed to DNA damaging-induced EBV reactivation. In contrast to the promoting effect of ATM on the lytic EBV reactivation in normoxia, ATM inhibited lytic EBV gene expression and decreased the EBV viral load in the prescence of hypoxia-induced DNA damage. miR-18a reactivated EBV through inhibiting the ATM-mediated DNA damage response (DDR) and caused genomic instability.

Conclusions

Taken together, these results indicate that DNA-damaging agents and host microRNAs play roles in EBV reactivation. Our study supported the interplay between host cell DDR, environmental genotoxic stress and EBV.

Electronic supplementary material

The online version of this article (10.1186/s12885-018-5205-9) contains supplementary material, which is available to authorized users.

WITHDRAWN: MicroRNA-18a promotes proliferation and metastasis in oral squamous cell carcinoma via targeting KLF4

Ahead of Print article withdrawn by publisher.

MicroRNA-18a promotes hepatocellular carcinoma proliferation, migration, and invasion by targeting Bcl2L10

BACKGROUND

Hepatocellular carcinoma (HCC) is known to feature several microRNA dysregulations. This study aimed to determine and investigate the prognostic value of microRNA (miRNA/miR)-18a and its role in regulating the progression of HCC.

METHODS

miR-18a expressions in human HCC tissues, pair-matched adjacent normal liver tissues as well as in HCC cell lines were determined by quantitative real-time PCR. The prognostic value of miR-18a was determined using Kaplan-Meier survival analysis and multivariable Cox regression assay. The ability of miR-18a in promoting HCC progression was verified in vitro.

RESULTS

miR-18a expressions in HCC tissues and cells were more than twice those of the normal control group (P<0.05). miR-18a expression was associated with the alpha-fetoprotein (AFP) level, TNM stage, tumor size, and intrahepatic vascular invasion (P<0.05). Kaplan- Meier survival analysis revealed that HCC patients with high expression of miR-18a possessed a more unfavorable prognosis (log-rank P<0.001). Overexpression of miR-18a promoted cell apoptosis and proliferation, induced S phase transition, as well as enhanced the migration and invasion ability of HCC cells. miR-18a was found to directly target the downstream molecule Bcl2L10. Furthermore, overexpressing Bcl2L10 was able to partly reverse the promoting effects of miR-18a on HCC cell progression.

CONCLUSION

miR-18a may serve as a prognostic biomarker of HCC as it is demonstrated to carry out a decisive role in HCC progression by promoting HCC cell invasion, migration, and proliferation through targeting Bcl2L10.

IDO1 impairs NK cell cytotoxicity by decreasing NKG2D/NKG2DLs via promoting miR-18a

BACKGROUND

Indoleamine-2,3-dioxygenase 1 (IDO1) is an important enzyme for altering the tumour microenvironment and assisting tumour cells to escape the immune system.

RESULTS

In this study, a significant reduction in NK cell cytotoxicity that was associated with a high expression of IDO1 in a reconstructed tumour microenvironment was observed. In a co-culture system of tumour cell culture supernatant (TSN) and murine NK cell, IDO1 was substantially increased, while NKG2D was markedly downregulated in NK cells. Based on computational predictions, miR-18a, which has two definite binding sites consisting of the 3'UTR of NKG2D and the 3'UTR of NKG2D ligand (Mult-1), was suspected to be a negative regulator of which its conjoined. As expected, the IDO1 could promote the expression of miR-18a and promote the downregulation effect of miR-18a on NKG2D and NKG2DL, and INCB024360 (INCB) could reverse the result. For digging the mechanism deeper, we authenticated IDO1 promoted the combination of miR-18a and AGO2 after argonaute 2 (AGO2) co-immunoprecipitation, which then degraded Mult-1 mRNA and inhibited the translation of it, further destructing NK cell cytotoxicity.

CONCLUSION

Our findings revealed a new regulatory axis, IDO1/miR-18a/NKG2D/NKG2DL, in the regulation of NK cell function. This may provide insight into the mechanism of the priming effect of IDO1 inhibitors and miR-18a interference, then elicit possible new methods of cancer treatment.

c-Fos/microRNA-18a feedback loop modulates the tumor growth via HMBOX1 in human gliomas

Glioma is one of the most aggressive and lethal human cancers in central nervous system (CNS). Recent studies have identified many dysregulated microRNAs (miRNA, miR) in human glioma, which are a class of small non-coding RNA molecules. Increasing data have shown that miR-18a plays significant roles in several tumors. However, its effects on glioma are unclear. In this study, we found the elevated expression of c-Fos and miR-18a in tissues of human glioma patients and glioma cells. Then the miR-18a inhibitor or c-Fos siRNA were transfected into glioma cells line H4 to determine their effects on H4 cells. MTT assay showed that both miR-18a inhibitor and si-c-Fos suppressed the H4 cell proliferation. Transwell assay showed the reduced cell migration by miR-18a inhibitor and si-c-Fos in H4 cells. The increased level of H4 cells apoptosis by miR-18a inhibitor and si-c-Fos was also determined. Moreover, knockout of c-Fos decreased the miR-18a level, while miR-18a inhibitor reduced the c-Fos level in H4 cells. Added with the results of ChIP assay, this report showed a positive feedback between c-Fos and miR-18a. Finally, luciferase assay showed that HMBOX1 was directly targeted by miR-18a in H4 cells, and the HMBOX1 siRNA reversed the effects of miR-18a inhibitor on cell proliferation, migration and apoptosis of H4 cells. In conclusion, our study determine that c-Fos/miR-18a feedback loop promotes the tumor growth of gliomas by HMBOX1, providing important clues for understanding the key roles of transcription factor mediated mRNA-miRNA functional network in the regulation of gliomas.

Malignant canine mammary epithelial cells shed exosomes containing differentially expressed microRNA that regulate oncogenic networks

Background

Breast (mammary) cancers in human (BC) and canine (CMT) patients share clinical, pathological, and molecular similarities that suggest dogs may be a useful translational model. Many cancers, including BC, shed exosomes that contain microRNAs (miRs) into the microenvironment and circulation, and these may represent biomarkers of metastasis and tumor phenotype.

Methods

Three normal canine mammary epithelial cell (CMEC) cultures and 5 CMT cell lines were grown in serum-free media. Exosomes were isolated from culture media by ultracentrifugation then profiled by transmission electron microscopy, dynamic light scattering, and Western blot. Exosomal small RNA was deep-sequenced on an Illumina HiSeq2500 sequencer and validated by qRT-PCR. In silico bioinformatic analysis was carried out to determine microRNA gene and pathway targets.

Results

CMEC and CMT cell lines shed round, “cup-shaped” exosomes approximately 150–200 nm, and were immunopositive for exosomal marker CD9. Deep-sequencing averaged ~ 15 million reads/sample. Three hundred thirty-eight unique miRs were detected, with 145 having > ±1.5-fold difference between one or more CMT and CMEC samples. Gene ontology analysis revealed that the upregulated miRs in this exosomal population regulate a number of relevant oncogenic networks. Several miRNAs including miR-18a, miR-19a and miR-181a were predicted in silico to target the canine estrogen receptor (ESR1α).

Conclusions

CMEC and CMT cells shed exosomes in vitro that contain differentially expressed miRs. CMT exosomal RNA expresses a limited number of miRs that are up-regulated relative to CMEC, and these are predicted to target biologically relevant hormone receptors and oncogenic pathways. These results may inform future studies of circulating exosomes and the utility of miRs as biomarkers of breast cancer in women and dogs.

Electronic supplementary material

The online version of this article (10.1186/s12885-018-4750-6) contains supplementary material, which is available to authorized users.

PIAS3-mediated feedback loops promote chronic colitis-associated malignant transformation

Rationale: Colitis-associated colorectal cancer (CAC) usually exhibits an accelerated disease progression, an increased resistance to therapeutic drugs and a higher mortality rate than sporadic colorectal cancer (CRC). PIAS3 is a member of the protein inhibitor of activated STAT (PIAS) family; however, little is known about the expression and biological functions of PIAS3 in CAC. The aim of our study was to investigate the biological mechanisms of PIAS3 in CAC. Methods: PIAS3 expression was examined in colon tissues of CAC/CRC patients and azoxymethane-dextran sulfate sodium (AOM-DSS)-induced mice. The role of PIAS3 was studied using a series of in vitro, in vivo and clinical approaches. Results: Downregulated PIAS3 expression, upregulated miR-18a expression and highly activated NF-κB and STAT3 were observed in colon tissues of CAC/CRC patients and AOM-DSS-induced mice. In vitro experiments revealed that PIAS3 significantly inhibited the activation of NF-κB and STAT3 and demonstrated that activated NF-κB and STAT3 transcriptionally regulated miR-18a level, and up-regulation of miR-18a expression led to defective PIAS3 expression. Moreover, PIAS3-mediated autoregulatory feedback loops (PIAS3/NF-κB/miR-18a and PIAS3/STAT3/miR-18a) were verified in vitro and were found to regulate cell proliferation. Additionally, modulation of the feedback loops via overexpression of PIAS3 or knockdown of miR-18a significantly inhibited cell proliferation in a mouse CRC xenograft model. Furthermore, upregulation of PIAS3 by intracolonic administration of PIAS3 lentivirus or anti-miR-18a lentivirus in AOM-DSS-induced mice led to dramatically reduced tumor sizes/numbers, whereas knockdown of PIAS3 in CAC mice significantly promoted tumor growth. Conclusion: Our data clearly show that PIAS3-mediated feedback loops control cell proliferation and function as robust driving forces for CAC progression. Targeting these highly activated feedback loops might offer promising therapeutic strategies for CAC.

LncRNA SNHG1 regulates cerebrovascular pathologies as a competing endogenous RNA through HIF-1α/VEGF signaling in ischemic stroke

Studies have shown that long noncoding ribonucleic acids (lncRNAs) play critical roles in multiple biologic processes. However, the Small Nucleolar RNA Host Gene 1 (SNHG1) function and underlying molecular mechanisms in ischemic stroke have not yet been reported. In the present study, we found that SNHG1 expression was remarkably increased both in isolated cerebral micro-vessels of a middle cerebral artery occlusion (MCAO) mice model, and in oxygen-glucose deprivation (OGD)-cultured mice brain micro-vascular endothelial cells (BMECs), meanwhile, the SNHG1 level was negatively correlated with miR-18a in MCAO mice. Mechanistically, SNHG1 inhibition presents larger brain infarct size and worsens neurological scores in MCAO mice. Consistent with the in vivo findings, SNHG1 inhibition also significantly increased caspase-3 activity and cell apoptosis in OGD-cultured BMECs. Furthermore, we found that SNHG1 functions as a competing endogenous RNA (ceRNA) for miR-18a, thereby regulating the de-repression of its endogenous target HIF-1α and promoting BMEC survival through HIF-1α/VEGF signaling. This study found a neuroprotective effect of SNHG1 mediated by HIF-1α/VEGF signaling through acting as a ceRNA for miR-18a. These findings reveal a novel function of SNHG1, which contributes to an extensive understanding of ischemic stroke and provides novel therapeutic options for this disease.

Long non-coding RNA UCA1 desensitizes breast cancer cells to trastuzumab by impeding miR-18a repression of Yes-associated protein 1

Breast cancer resistance to the monoclonal erbB2/HER2 antibody trastuzumab (or herceptin) has become a significant obstacle in clinical targeted therapy of HER2-positive breast cancer. Previous research demonstrated that such drug resistance may be related to dysregulation of miRNA expression. Here, we found that knockdown of the long non-coding RNA, urothelial cancer associated 1 (UCA1), can promote the sensitivity of human breast cancer cells to trastuzumab. Mechanistically, UCA1 knockdown upregulated miR-18a and promoted miR-18a repression of Yes-associated protein 1 (YAP1). A luciferase reporter assay confirmed the association of miR-18a with wild-type UCA1 but not with UCA1 mutated at the predicted miR-18a-binding site. The direct targeting of YAP1 by miR-18a was verified by the observation that miR-18a mimic suppressed luciferase expression from a construct containing the YAP1 3' untranslated region. Meanwhile, reciprocal repression of UCA1 and miR-18a were found to be Argonaute 2-dependent. Knockdown of YAP1 recapitulated the effect of UCA1 silencing by reducing the viability of trastuzumab-treated breast cancer cells, whereas inhibition of miR-18a abrogated UCA1 knockdown-induced improvement of trastuzumab sensitivity in breast cancer cells. These findings demonstrate that the UCA1/miR-18a/YAP1 axis plays an important role in regulating the sensitivity of breast cancer cells to trastuzumab, which has implications for the development of novel approaches to improving breast cancer responses to targeted therapy.

ACE2-EPC-EXs protect ageing ECs against hypoxia/reoxygenation-induced injury through the miR-18a/Nox2/ROS pathway

Oxidative stress is one of the mechanisms of ageing‐associated vascular dysfunction. Angiotensin‐converting enzyme 2 (ACE2) and microRNA (miR)‐18a have shown to be down‐regulated in ageing cells. Our previous study has shown that ACE2‐primed endothelial progenitor cells (ACE2‐EPCs) have protective effects on endothelial cells (ECs), which might be due to their released exosomes (EXs). Here, we aimed to investigate whether ACE2‐EPC‐EXs could attenuate hypoxia/reoxygenation (H/R)‐induced injury in ageing ECs through their carried miR‐18a. Young and angiotensin II‐induced ageing ECs were subjected to H/R and co‐cultured with vehicle (medium), EPC‐EXs, ACE2‐EPCs‐EXs, ACE2‐EPCs‐EXs + DX600 or ACE2‐EPCs‐EXs with miR‐18a deficiency (ACE2‐EPCs‐EXs^{anti‐miR‐18a}). Results showed (1) ageing ECs displayed increased senescence, apoptosis and ROS production, but decreased ACE2 and miR‐18a expressions and tube formation ability; (2) under H/R condition, ageing ECs showed higher rate of apoptosis, ROS overproduction and nitric oxide reduction, up‐regulation of Nox2, down‐regulation of ACE2, miR‐18a and eNOS, and compromised tube formation ability; (3) compared with EPC‐EXs, ACE2‐EPC‐EXs had better efficiencies on protecting ECs from H/R‐induced changes; (4) The protective effects were less seen in ACE2‐EPCs‐EXs + DX600 and ACE2‐EPCs‐EXs^{anti‐miR‐18a} groups. These data suggest that ACE‐EPCs‐EXs have better protective effects on H/R injury in ageing ECs which could be through their carried miR‐18a and subsequently down‐regulating the Nox2/ROS pathway.

Grapefruit-derived nanovectors deliver miR-18a for treatment of liver metastasis of colon cancer by induction of M1 macrophages

Liver metastasis accounts for many of the cancer deaths in patients. Effective treatment for metastatic liver tumors is not available. Here, we provide evidence for the role of miR-18a in the induction of liver M1 (F4/80⁺interferon gamma (IFNγ)⁺IL-12⁺) macrophages. We found that miR-18a encapsulated in grapefruit-derived nanovector (GNV) mediated inhibition of liver metastasis that is dependent upon the induction of M1 (F4/80⁺IFNγ⁺IL-12⁺) macrophages; depletion of macrophages eliminated its anti-metastasis effect. Furthermore, the miR-18a mediated induction of macrophage IFNγ by targeting IRF2 is required for subsequent induction of IL-12. IL-12 then activates natural killer (NK) and natural killer T (NKT) cells for inhibition of liver metastasis of colon cancer. This conclusion is supported by the fact that knockout of IFNγ eliminates miR-18a mediated induction of IL-12, miR-18a treatment has an anti-metastatic effects in T cell deficient mice but there is no anti-metastatic effect on NK and NKT deficient mice. Co-delivery of miR-18a and siRNA IL-12 to macrophages did not result in activation of co-cultured NK and NKT cells. Taken together our results indicate that miR-18a can act as an inhibitor for liver metastasis through induction of M1 macrophages.

Regulatory role of miR-18a to CCN2 by TGF-β1 signaling pathway in pulmonary injury induced by nano-SiO2

This research is designed to investigate the regulatory effect of miR-18a to the target gene connective tissue growth factor (CTGF, or CCN2), by participating in TGF-β1 signaling pathway and explore the pathogenic mechanism of miR-18a in pulmonary injury induced by nano-SiO₂ based on our early study. miR-18a and expression of TGF-β1 in Chinese hamster lung (CHL) fibroblasts cells stimulated by supernatants of NR8383 cells exposed to 40 μg/ml nano-SiO₂ for 24 h demonstrated 1.58 ± 0.22-fold and 1096.00 ± 2.60 pg/ml increase compared with blank control group analyzed by real-time quantitative PCR (RT-qPCR) and enzyme-linked immunosorbent assay (ELISA), respectively. Expression increase of miR-18a and reduction of CCN2 mRNA expression levels and protein gray value ratio detected by Western blotting in CHL cells transfect miR-18a mimics for 48 h. The reverse of CHL cell transfection miR-18a inhibit is also true. The result of miR-18a and CCN2 binding sites tested by luciferase reporter gene assay shows that the report relative fluorescence value of miR-18a mimics wild type on CCN2 is 0.50 ± 0.02 with the control of mimics NC and mutant relative fluorescence report value 0.86 ± 0.04 (P < 0.05). Expression levels of miR-18a, CCN2 mRNA, and protein gray value ratio decreased in CHL cells treated by TGF-β1, respectively, and vice versa treated by TGF-β1corepressor. The results suggest that CCN2 is the target gene regulated by miR-18a and miR-18a participates in TGF-β1 signaling pathway by regulating the expression of CCN2 negatively through CCN2 3'UTR site, and thus may be involved in the development process of pulmonary injury.

High circulating miR-18a, miR-20a, and miR-92a expression correlates with poor prognosis in patients with non-small cell lung cancer

The purpose of this study was to assess the predictive value of angiogenic miRNAs for disease-free survival (DFS) and overall survival (OS) of patients with non-small cell lung cancer (NSCLC). In total, 196 patients with NSCLC (tumor lymph nodes metastasis (TNM) stage I-III) were enrolled and peripheral blood samples were collected. Total RNA was extracted from blood samples, and the relative expression levels of candidate miRNAs were evaluated by real time-polymerase chain reaction (RT-PCR). The median follow-up period was 56.7 months, and the final follow-up date was in August 2016. The median DFS of all patients was 30.0 (14.0-49.0) months, whereas the median OS was 41.5 (23.0-58.0) months. Furthermore, the 5-year DFS and OS rates were 11.3% and 32.3%, respectively. Kaplan-Meier (K-M) curves showed that high plasma miR-18a (P < 0.001), miR-20a (P < 0.001), miR-92a (P < 0.001), miR-126 (P < 0.001), miR-210 (P = 0.003), and miR-19a (P = 0.027) expressions levels correlated with a worse DFS. Moreover, patients with high plasma miR-18a, miR-20a, miR-92a, miR-210, and miR-126 expression levels had a shorter OS than patients with low expression levels of these miRNAs (all P <= 0.001). Furthermore, multivariate Cox regression analyses revealed that high plasma expression levels of miR-18a, miR-20a, and miR-92a as well as lymphatic node metastasis (all P < 0.001) were independent risk factors for both DFS and OS in patients with NSCLC. Thus, the circulating miR-18a, miR-20a, and miR-92a levels may serve as novel and promising prognostic biomarkers in patients with NSCLC.

MicroRNA-18a promotes proliferation and metastasis in hepatocellular carcinoma via targeting KLF4

MicroRNAs (miRNAs) are short, non-coding and endogenous RNAs that played as important roles in the proliferation and metastasis of tumors. In this study, we determined the role of miR-18a in the regulation of HCC cell motility. We showed that miR-18a expression was upregulated in human HCC tissues and cell lines. Moreover, Elevated expression of miR-18a promoted the HCC cell proliferation and migration. KLF4 was identified as a direct target of miR-18a in HCC cells. Furthermore, overexpression of KLF4 attenuated the effects of miR-18a on the regulation of HCC cell motility. The expression of KLF4 was negatively associated with the expression of miR-18a expression in HCC tissues. We also showed that the cell cycle inhibitor p21 was aberrantly downregulated in HCC cells, whereas this inhibition was reversed by miR-18a inhibitor. These data indicated that miR-18a may play a positive role in hepatocellular carcinoma by promoting the proliferation and migration of HCC cells through targeting KLF4 as well as downstream p21.

Roles of lncRNA UCA1-miR-18a-SOX6 axis in preventing hypoxia injury following cerebral ischemia

The present study aimed to elucidate the roles and possible molecular mechanisms of long noncoding RNA (lncRNA) urothelial carcinoma associated 1 (UCA1) in neuronal pheochromocytoma (PC)-12 cells under hypoxic conditions. The neuronal PC-12 cells were exposed to hypoxic and normoxic conditions followed by the measurement of the expression of lncRNA UCA1. In addition, the cells were transfected with short hairpin RNAs (sh-RNAs) against UCA1 (sh-UCA1), SOX6 (sh-SOX6), negative control (sh-NC), pEX-SOX6, pEX, miR-18a mimic, mimic NC, miR-18a inhibitor, and inhibitor NC. Under different treatments of transfection, cell viability and migration and invasion potential were analyzed. In addition, the induction of apoptosis was investigated by studying the expression profiles of apoptosis-related proteins. Hypoxia treatment significantly enhanced the expression of UCA1, which in turn induced injury in PC-12 cells characterized by the inhibition of cell viability, the reduction in migration and invasion potential, and the promotion of cell apoptosis. Moreover, the suppression of UCA1 alleviated the hypoxia injury. In addition, the relationship between UCA1 and miR-18a and between miR-18a and SRY-box containing gene 6 (SOX6) were explored. MiR-18a was found to be a direct target of UCA1, an upregulation of which mediated the effects of suppression of UCA1 (alleviated hypoxic injury). Besides, SOX6 was found to be a target of miR-18a whose expression could be negatively regulated by miR-18a. An overexpression of SOX6 could also aggravate hypoxia injury in PC-12 cells, whereas a knockdown of SOX6 exhibited contrary results. Our findings indicated that the down-regulation of UCA1 promoted the expression of miR-18a that led to a reduction in the expression of its target protein, SOX6, thereby contributing to the hypoxia injury following cerebral ischemia.

Resveratrol inhibits apoptosis by increase in the proportion of chondrocytes in the S phase of cell cycle in articular cartilage of ACLT plus Mmx rats

The current study was aimed to investigate the effect of resveratrol on apoptosis inhibition in chondrocytes in ACLT plus Mmx rat model. TUNEL assay revealed a markedly higher level of apoptotic chondrocytes in the cartilage of untreated ACLT plus Mmx rats. The percentage of apoptotic chondrocytes was found to be 29.5 and 40.75%, respectively at 21 and 45 days. The percentage of apoptotic chondrocytes at 21 and 45 days in resveratrol (5 mg/kg) treated ACLT plus Mmx rats was found to be 13% and 2%, respectively. Real-time PCR analysis revealed that treatment of the ACLT plus Mmx rats with resveratrol for 45 days caused a significant increase in the expression of miR-18a compared to that in untreated rats. Flow cytometry and BrdUrd incorporation assay revealed that the proportion of chondrocytes in the S phase was increased to 51.4% in resveratrol treatment group compared to 25.3% in the untreated ACLT plus Mmx rats. Western blot analysis showed that treatment of the ACLT plus Mmx rats with resveratrol decreased the expression of ATM protein kinase and GFP protein without any effect on the expression of GFP-_ϒ-tubulin in chondrocytes. In addition, resveratrol treatment also led to reduction in the activity of luciferase in the chondrocytes of ACLT plus Mmx rats. Resveratrol treatment of the ACLT plus Mmx rats decreases the expression level of ATM protein and checkpoint kinase 2 (CHK2) phosphorylation in chondrocytes. H2AX and 53BP1 phosphorylation was decreased in ACLT plus Mmx rats on treatment with resveratrol for 45 days. Immunofluorescence results revealed a markedly lower level of H2AX and 53BP1 nuclear foci in the chondrocytes of ACLT plus Mmx rats treated with resveratrol. Thus resveratrol treatment of the ACLT plus Mmx rats inhibits chondrocyte apoptosis and increases proportion of cells in the S phase of cell cycle which may be through the increase in expression of miR18a. A significant relation appears between resveratrol and miR-18a expression in the chondrocytes.

miR-18a-5p Inhibits Sub-pleural Pulmonary Fibrosis by Targeting TGF-β Receptor II

Idiopathic pulmonary fibrosis (IPF) is a chronic progressive lung disease that typically leads to respiratory failure and death within 3-5 years of diagnosis. Sub-pleural pulmonary fibrosis is a pathological hallmark of IPF. Bleomycin treatment of mice is a an established pulmonary fibrosis model. We recently showed that bleomycin-induced epithelial-mesenchymal transition (EMT) contributes to pleural mesothelial cell (PMC) migration and sub-pleural pulmonary fibrosis. MicroRNA (miRNA) expression has recently been implicated in the pathogenesis of IPF. However, changes in miRNA expression in PMCs and sub-pleural fibrosis have not been reported. Using cultured PMCs and a pulmonary fibrosis animal model, we found that miR-18a-5p was reduced in PMCs treated with bleomycin and that downregulation of miR-18a-5p contributed to EMT of PMCs. Furthermore, we determined that miR-18a-5p binds to the 3' UTR region of transforming growth factor β receptor II (TGF-βRII) mRNA, and this is associated with reduced TGF-βRII expression and suppression of TGF-β-Smad2/3 signaling. Overexpression of miR-18a-5p prevented bleomycin-induced EMT of PMC and inhibited bleomycin-induced sub-pleural fibrosis in mice. Taken together, our data indicate that downregulated miR-18a-5p mediates sub-pleural pulmonary fibrosis through upregulation of its target, TGF-βRII, and that overexpression of miR-18a-5p might therefore provide a novel approach to the treatment of IPF.

Downregulation of miR-18a induces CTGF and promotes proliferation and migration of sodium hyaluronate treated human corneal epithelial cells

Properly controlled corneal epithelial wound healing is critical for health of cornea, which involves cell proliferation, migration, anchoring and differentiation. Sodium hyaluronate (SH) has been proven to exert beneficial pharmacological effect on corneal wound healing, though the underlying mechanism remained open to investigation. MicroRNAs (miRNAs) are small single-stranded RNAs that could bind to 3'UTR of mRNAs of target genes. The multi-target regulation of miRNAs may favor treatment of corneal wound given the complicated processes implicated in the healing process, which has inspired initiatives to develop miRNA therapy in corneal wound healing. In this light, we used miRNAs profiling to detect whether miRNAs are also implicated in the mechanism underlying the stimulatory effect of SH on corneal epithelial wound healing. We found miR-18a was most susceptible to SH treatment, the target prediction of which were enriched in a bunch of pathways implicated in corneal wound healing. Connective tissue growth factor (CTGF) was found to be overrepresented in most significant enriched pathways and was experimentally confirmed as a bona fide target of miR-18a, which modulated cell migration and proliferation of human corneal epithelial cells.

miR-18a promotes cell proliferation of esophageal squamous cell carcinoma cells by increasing cylin D1 via regulating PTEN-PI3K-AKT-mTOR signaling axis

Esophageal squamous cell carcinoma (ESCC) is one of the lethal cancers with a high incidence rate in Asia. Cyclin D1 is overexpressed and plays an important role in the carcinogenesis of ESCC; however the mechanism of the deregulation of Cyclin D1 in ESCC remains to be determined. In the study, we found that miR-18a promotes the expression Cyclin D1 by targeting PTEN in eophageal squamous cell carcinoma TE13 and Eca109 cells. Transfection of miR-18a mimetics increased cyclin D1, while transfection of miR-18a antagomir decreased D1. Moreover, miR-18a-mediated upregulation of cyclin D1 was accompanied with downregulation of PTEN, which is a direct target of miR-18a, and increase of the phosphorylation of AKT and S6K1. In addition, pharmacologic inhibition of AKT or mTOR kinases abolished the increase of cyclinD1 by miR-18a, which was accompanied with decreased phosphorylation of RbS780 and inhibition of cell proliferation. Our results demonstrated the upregulation of miR-18a promoted cell proliferation by increasing cylin D1 via regulating PTEN-PI3K-AKT-mTOR signaling axis, suggesting that small molecule inhibitors of AKT-mTOR signaling are potential agents for the treatment of ESCC patients with upregulation of miR-17-92 cluster.

MicroRNA-18a modulates P53 expression by targeting IRF2 in gastric cancer patients

BACKGROUND AND AIM

MicroRNA-18a (miR-18a) has been reported to be upregulated in gastric cancer (GC) tissues compared with normal gastric tissues. However, little is known about its prognostic value and biological roles.

METHODS

In this study, miR-18a expression in gastric adenocarcinoma (GAC) tissues and adjacent non-tumor tissues was validated by in situ hybridization, and the predictive values of miR-18a were explored. The biological roles of miR-18a and the underlying signal pathway were investigated in GC cell lines.

RESULTS

Overexpressed intra-tumoral miR-18a was associated with poor survival rate and was an independent prognostic factor for overall survival rate (P < 0.001) in GC patients. Forced expression of miR-18a remarkably enhanced cell proliferation, migration, and invasion in GC cells, while inhibition of miR-18a caused the opposite effects. Further study showed that miR-18a suppressed the expression of interferon regulatory factor 2 (IRF2) by directly binding to its 3'-untranslated region. Moreover, miR-18a expression levels are inversely correlated with IRF2 in human GC tissues. Western blot showed that forced expression of miR-18a could not only downregulate the expression of IRF2, but also inhibit the expression of P53, suggesting that IRF2 might play as a tumor suppressor by regulating P53 signaling in GC.

CONCLUSION

miR-18a modulated P53 expression by directly targeting IRF2 and had a high predictive value for prognosis of GAC patients. These results may lead to identification of therapeutic candidates of GC.

Endoplasmic Reticulum Stress in Hepatic Stellate Cells Promotes Liver Fibrosis via PERK-Mediated Degradation of HNRNPA1 and Up-regulation of SMAD2

BACKGROUND & AIMS

Endoplasmic reticulum (ER) stress has been implicated in a variety of diseases. Hepatic stellate cells (HSCs) contribute to the development of liver fibrosis. Information on the link between ER stress and HSC activation is scarce. We investigated the effects of ER stress in HSCs on the progression of liver fibrosis and the regulation of this process in cells and mice.

METHODS

Proteins and messenger RNAs were measured in 2 sets of liver samples (n = 25 and n = 44) collected from patients with chronic hepatitis C virus infection and/or fibrosis. ER stress was induced in cells and mice using chemical agents. Lentiviral vectors were constructed to express glucose-regulated protein 78 (GRP78; also known as HSPA5) or heterogeneous nuclear ribonucleoprotein A1 (HNRNPA1) from the α-smooth muscle actin promoter and injected into C57BL/6 mice for HSC-specific gene expression. Liver tissues and HSCs were collected from mice or rats and analyzed using immunoblottings and quantitative reverse-transcription polymerase chain reaction. LX-2 cells were transfected with small interfering RNAs, microRNA mimics, or overexpression vectors.

RESULTS

Hepatic ER stress was much higher in liver tissues from patients with severe vs mild fibrosis. ER stress induced fibrogenic genes in HSCs. Targeted lentiviral delivery of glucose-regulated protein 78 to HSCs in mice reduced fiber accumulation in liver. Levels of SMAD2, but not SMAD3, were increased in fibrotic liver tissues from patients or mice exposed to ER stress; small interfering RNA-mediated knockdown of SMAD2 reduced ER stress-mediated activation of HSCs. In rat HSCs, ER stress increased levels of SMAD2 messenger RNA by decreasing levels of microRNA 18a (MIR18A), an inhibitor of SMAD2 expression, rather than transactivating the SMAD2 gene. ER stress-activated PKR-like endoplasmic reticulum kinase, also known as EIF2AK3 (PERK) phosphorylated HNRNPA1, a protein required for the maturational processing of primary MIR18A, at Thr51, accelerating its degradation. Overexpression of HNRNPA1 (or its T51A mutant) in HSCs of mice inhibited liver fibrosis. Severe fibrotic liver tissues from patients had increased levels of phosphorylated PERK and reduced levels of HNRNPA1 in HSCs, compared with mild fibrotic liver tissues.

CONCLUSIONS

ER stress in HSCs promotes liver fibrosis by inducing overexpression of SMAD2, via dysregulation of MIR18A; this dysregulation is mediated by PERK phosphorylation and destabilization of HNRNPA1.

Overexpression of miR-18a negatively regulates myocyte enhancer factor 2D to increase the permeability of the blood-tumor barrier via Krüppel-like factor 4-mediated downregulation of zonula occluden-1, claudin-5, and occludin

miR-18a represses angiogenesis and tumor evasion by weakening vascular endothelial growth factor and transforming growth factor-β signaling to prolong the survival of glioma patients, although it is thought to be an oncogene. This study investigates the potential effects of miR-18a on the permeability of the blood-tumor barrier (BTB) and its possible molecular mechanisms. An in vitro BTB model was successfully established. The endogenous expression of miR-18a in glioma vascular endothelial cells (GECs) was significantly lower than that in normal vascular ECs, and the overexpression of miR-18a significantly increased the permeability of the BTB as well as downregulating the mRNA and protein expressions of tight junction-related proteins zonula occluden-1 (ZO-1), claudin-5, and occludin in GECs. Dual luciferase reporter assays revealed that miR-18a bound to the 3'-untranslated region (3'UTR) of myocyte enhancer factor 2D (MEF2D). The overexpression of both miR-18a and MEF2D with the 3'UTR significantly weakened the effect caused by miR-18a of decreasing the mRNA and protein expressions of ZO-1, claudin-5 and occludin and of increasing the permeability of the BTB. Chromatin immunoprecipitation showed that MEF2D could directly bind to KLF4 promoter. This study shows that miR-18a targets and negatively regulates MEF2D, which further regulates tight junction-related proteins ZO-1, claudin-5, and occludin through transactivation of KLF4 and, finally, changes the permeability of the BTB. MiR-18a should garner growing attention because it might serve as a potential target in opening the BTB and providing a new strategy for the treatment of gliomas.

Effect of miR-18a overexpression on the radiosensitivity of non-small cell lung cancer

The aim of the present study is to investigate whether there is a relationship between miR-18a expression and radiosensitization of non-small-cell lung caner (NSCLC). The relationship between miR-18a expression and clinicopathological characteristics was investigated. To determine whether the miR-18a expression levels were associated with radiotherapeutic efficacy, therapeutic response was evaluated by radiologic Response Evaluation Criteria in Solid Tumors (RECIST). To determine whether miR-18a was required for lung cancer cell radioresistance, A549 cells were treated with different doses of ionizing radiation, following transfection with inhibitor miR-18a or inhibitor NC. We found that the level of miR-18a in NSCLC was strongly correlated with tumor differentiation (P = 0.026), regional lymph node metastasis (P = 0.013) and clinical TNM stage (P = 0.005). According to RECIST, miR-18a expression level was significantly associated with therapeutic response, exhibiting higher expression level in non-responsive patients. Furthermore, the depletion of miR-18a increased A549 cell radiosensitivity. In conclusion, we provide the evidence that down-regulation of miR-18a sensitizes NSCLC to radiation treatment, and it may help to develop a new approach to sensitizing radioresistant lung cancer cells by targeting miR-18a.

MiR-18a increased the permeability of BTB via RUNX1 mediated down-regulation of ZO-1, occludin and claudin-5

The purposes of this study were to investigate the possible molecular mechanisms of miR-18a regulating the permeability of blood-tumor barrier (BTB) via down-regulated expression and distribution of runt-related transcription factor 1 (RUNX1). An in vitro BTB model was established with hCMEC/D3 cells and U87MG cells to obtain glioma vascular endothelial cells (GECs). The endogenous expressions of miR-18a and RUNX1 were converse in GECs. The overexpression of miR-18a significantly impaired the integrity and increased the permeability of BTB, which respectively were detected by TEER and HRP flux assays, accompanied by down-regulated mRNA and protein expressions and distributions of ZO-1, occludin and claudin-5 in GECs. Dual-luciferase reporter assay was carried out and revealed RUNX1 is a target gene of miR-18a. Meanwhile, mRNA and protein expressions and distribution of RUNX1 were downregulated by miR-18a. Most important, miR-18a and RUNX1 could reversely regulate the permeability of BTB as well as the expressions and distributions of ZO-1, occludin and claudin-5. Finally, chromatin immunoprecipitation verified that RUNX1 interacted with "TGGGGT" DNA sequence in promoter region of ZO-1, occludin and claudin-5 respectively. Taken together, our present study indicated that miR-18a increased the permeability of BTB via RUNX1 mediated down-regulation of tight junction related proteins ZO-1, occludin and claudin-5, which would attract more attention to miR-18a and RUNX1 as potential targets of drug delivery across BTB and provide novel strategies for glioma treatment.

Plasma miR-200c and miR-18a as potential biomarkers for the detection of colorectal carcinoma

It has been demonstrated that there are abundant stable microRNAs (miRNAs) in plasma/serum, which can be detected and are potentially disease-specific. The aim of this study was to investigate whether plasma miR-200c and miR-18a can be used as biomarkers for the detection of colorectal carcinoma (CRC). This study was divided into three parts: i) confirmation of higher miR-200c and miR-18a levels in primary CRC tissues compared to normal colorectal tissues; ii) evaluation of plasma miR-200c and miR-18a expression by comparing 78 patients with 86 healthy volunteers and iii) comparison of miR-200c and miR-18a levels in paired pre-and post-operative plasma in cancer patients who underwent curative CRC resection. Results showed that the expression of miR-200c and miR-18a was significantly higher in CRC compared to normal tissues. The plasma levels of miR-200c and miR-18a were significantly higher in CRC patients compared to controls. miR-200c yielded an area under the receiver-operating characteristics (ROC) curve (AUC) of 0.749 and miR-18a yielded an AUC of 0.804 when distinguishing CRC patients from the controls. Combined ROC analyses using the two miRNAs revealed an elevated AUC of 0.839 with 84.6% sensitivity and 75.6% specificity in discriminating CRC. Plasma levels of miR-200c and miR-18a were significantly lower in post-operative compared to pre-operative samples. The results of this study suggest that plasma miR-200c and miR-18a are significantly elevated in the plasma of CRC patients and that they may serve as non-invasive molecular markers for CRC screening.