Potentially important microRNA cluster on chromosome 17p13.1 in primary peritoneal carcinoma

miR-497/195 Cluster Affects the Development of Colorectal Cancer by Targeting FRA1

The miR-497-195 cluster facilitates the occurrence and development of cancer. This study aims to investigate whether the miR-195-497 cluster could regulate the progression of colorectal cancer by regulating the common target gene, FOS-related antigen 1 (FRA1). Overexpression of the miR-195/497 vector was used to evaluate the effect of overexpression of miR-195-497 clusters on the biological behavior of colon cancer cells. In animal experiments, tumor growth and metastasis were recorded by constructing a nude mouse model of a subcutaneously implanted tumor. miR-195 and miR-497 were expressed to varying degrees in Caco-2, LoVo, and HT-29 cells. Overexpression of miR-195/497 and inhibition of FRA1 decreased HT-29 cell proliferation, inhibited cell invasion and migration, and promoted Epithelial-mesenchymal transition (EMT). In vivo experiments showed that the overexpression of miR-195/497 or inhibition of FRA1 inhibited tumor growth, affected EMT in tumor cells, and inhibited the expression of FRA1. Additionally, the aforementioned conditions had the best effect when used together. The miR-195-497 cluster can regulate the proliferation, EMT, invasion, and migration of colorectal cancer cells by regulating the common target gene FRA1, thereby affecting the development of colorectal cancer.

Expression of microRNAs ‘let-7d and miR-195’ and Apoptotic Genes ‘BCL2 and Caspase-3’ as Potential Biomarkers of Female Breast Carcinogenesis

Objective: Breast cancer (BC) is the most common cause of cancer-related death among women worldwide. Let-7d and microRNA-195 (miR-195) are members of microRNAs that are known tumor suppressors and are involved in the regulation of apoptosis, invasion, and other cellular functions. However, the roles of these microRNAs in BC progression remain controversial. This study aimed to explore the correlation between the expression of let-7d and miR-195 and apoptosis-related genes (ARGs) “B-cell lymphoma 2 (BCL2) and caspase-3 (CASP3)” as potential biomarkers of breast carcinogenesis. Methods: It was a retrospective case-control study in which expression of let-7d, miR-195, CASP3, and BCL2 was assessed using quantitative real-time PCR (qRT-PCR); and immunohistochemical (IHC) staining was used to determine expression of BCL2 and CASP3 in BC tissue versus normal breast tissue (NT) samples. Results: The expression of let-7d and miR-195 was significantly reduced within BC tissues compared to NT (P: < 0.0001); and there was a statically positive correlation between them (r=0.314, P: 0.005). They have also been correlated to biomarkers’ expression of genes related to apoptosis. There was a statistically significant positive association between CASP3, and both let-7d, and miR-195 relative gene expression (r=0.713, P: <0.0001 and r=0.236, P: 0.03, respectively). In contrast, there was a statistically significant negative association between the relative gene expression of BCL2, with let-7d, and miR-195 (r=-0.221, P: 0.04 and r=-0.311, P: 0.005, respectively). Conclusion: Let-7d and miR-195 have been suggested to be involved in BC through modulation of the ARGs including BCL2 and CASP3. The qRT-PCR and IHC studies demonstrated that decreased expression of let-7d and miR-195 prohibits apoptosis via downregulating CASP3 and increasing BCL2 expressions promoting BC progression. These results also hypothesize that let-7d and miR-195 along with apoptotic biomarkers (BCL2 and CASP3) can be used in the future to introduce novel, non-invasive molecular biomarkers for BC into clinical practice.

Circulating microRNAs can predict chemotherapy-induced toxicities in patients being treated for primary breast cancer

PURPOSE

Prescribing NAC for breast cancer is a pragmatic treatment strategy for several reasons; however, certain patients suffer chemotherapy-induced toxicities. Unfortunately, identifying patients at risk of toxicity often proves challenging. MiRNAs are small non-coding RNA molecules which modulate genetic expression. The aim of this study was to determine whether circulating miRNAs are sensitive biomarkers that can identify the patients likely to suffer treatment-related toxicities to neoadjuvant chemotherapy (NAC) for primary breast cancer.

METHODS

This secondary exploratory from the prospective, multicentre translational research trial (CTRIAL ICORG10/11-NCT01722851) recruited 101 patients treated with NAC for breast cancer, from eight treatment sites across Ireland. A predetermined five miRNAs panel was quantified using RQ-PCR from patient bloods at diagnosis. MiRNA expression was correlated with chemotherapy-induced toxicities. Regression analyses was performed using SPSS v26.0.

RESULTS

One hundred and one patients with median age of 55 years were recruited (range: 25-76). The mean tumour size was 36 mm and 60.4% had nodal involvement (n = 61) Overall, 33.7% of patients developed peripheral neuropathies (n = 34), 28.7% developed neutropenia (n = 29), and 5.9% developed anaemia (n = 6). Reduced miR-195 predicted patients likely to develop neutropenia (P = 0.048), while increased miR-10b predicted those likely to develop anaemia (P = 0.049). Increased miR-145 predicted those experiencing nausea and vomiting (P = 0.019), while decreased miR-21 predicted the development of mucositis (P = 0.008).

CONCLUSION

This is the first study which illustrates the value of measuring circulatory miRNA to predict patient-specific toxicities to NAC. These results support the ideology that circulatory miRNAs are biomarkers with utility in predicting chemotherapy toxicity as well as treatment response.

MicroRNA and gynecological cancers: Focus on miR-195

Different cancer types have been shown to have down-regulated expression levels of miR-195 as an anti-tumor agent. MiR-195 family members can inhibit cancer cell proliferation, angiogenesis, epithelial-mesenchymal transition and metastases, immunosuppression, glycolysis, drug resistance, and cancer stem cell development by targeting the 3'-UTR of the mRNA of different pro-tumor genes. MiR-195 identified as a tumor suppressor miR in a variety of cancers, most notably gynecological malignancies such as cervical, endometrial, and ovarian carcinoma. As a result, restoring miR-195 expression should be regarded as a potential therapy for either prevention or treatment of gynecological cancers. This review will present the most recent data about miR-195-mediated anti-tumor effects in gynecological malignancies, emphasizing its downstream signaling pathways and target genes, as well as prospective treatment techniques.

Novel targets in rectal cancer by considering lncRNA-miRNA-mRNA network in response to Lactobacillus acidophilus consumption: a randomized clinical trial

We aimed to explore the lncRNA-miR-mRNA network in response to Lactobacillus acidophilus (L. acidophilus) consumption in rectal cancer patients. The candidate miRs were first taken from the GEO and TCGA databases. We constructed the lncRNA-miR-mRNA network using the high-throughput sequencing data. At last, we created a heatmap based on the experimental data to show the possible correlation of the selected targets. The expression levels of selected targets were measured in the samples of 107 rectal cancer patients undergoing placebo and probiotic consumption and 10 noncancerous subjects using Real-Time PCR. Our analysis revealed a group of differentially expressed 12 miRs and 11 lncRNAs, and 12 genes in rectal cancer patients. A significant expression increase of the selected tumor suppressor miRs, lncRNAs, and genes and a substantial expression decrease of the selected oncomiRs, onco-lncRNAs, and oncogenes were obtained after the probiotic consumption compared to the placebo group. There is a strong correlation between some network components, including miR-133b and IGF1 gene, miR-548ac and MSH2 gene, and miR-21 and SMAD4 gene. In rectal cancer patients, L. acidophilus consumption was associated with improved expression of the lncRNA-miR-mRNA network, which may provide novel monitoring and therapeutic approaches.

An innovative systematic approach introduced the involved lncRNA-miR-mRNA network in cell cycle and proliferation after conventional treatments in breast cancer patients

INTRODUCTION

The present study aimed to explore the involved lncRNA-miRNA-mRNA network in the cell cycle and proliferation after conventional treatments in Luminal A breast cancer patients.

METHODS

The candidate miRNAs (miRs), lncRNAs, and mRNAs were first taken from the Gene Expression Omnibus and TCGA databases. The lncRNA-miR-mRNA network was then constructed using the high-throughput sequencing data. The expression levels of selected targets were measured in the breast cancer and healthy samples by the Real-Time PCR technique and compared with the clinical outcomes by the Kaplan-Meier method.

RESULTS

Our analysis revealed a group of differentially expressed 3 lncRNAs, 9 miRs, and 14 mRNAs in breast cancer patients. A significant expression decrease of the selected tumor suppressor lncRNAs, miRs, and genes and a substantial expression increase of the selected onco-lncRNAs, oncomiRs, and oncogenes were obtained in the patients compared to the healthy group. The plasma levels of the lncRNAs, miRs, and mRNAs were more significant after the operation, chemotherapy, and radiotherapy than the pre-treatment. The Kaplan-Meier analysis indicated that the patients with a high expression of miR-21, miR-20b, IGF1R, and E2F2 and a low expression of miR-125a, PDCD4, and PTEN had exhibited a shorter overall survival rate.

CONCLUSION

Our results suggested that the underlying mechanisms of the lncRNA, miRs, and mRNAs and relevant signaling pathways may be considered predictive and therapeutic targets for breast cancer.

MicroRNA Expression Profiling Predicts Nodal Status and Disease Recurrence in Patients Treated with Curative Intent for Colorectal Cancer

Background: Approximately one-third of colorectal cancer (CRC) patients will suffer recurrence. MiRNAs are small non-coding RNAs that play important roles in gene expression. We aimed to correlate miRNA expression with aggressive clinicopathological characteristics and survival outcomes in CRC. Methods: Tumour samples were extracted from 74 CRC patients. MiRNAs were quantified using real-time reverse transcriptase polymerase chain reaction. Descriptive statistics and Cox regression analyses were performed to correlate miRNA targets with clinicopathological and outcome data. Results: Aberrant miR-21 and miR-135b expression correlate with increased nodal stage (p = 0.039, p = 0.022). Using univariable Cox regression analyses, reduced miR-135b (β-coefficient −1.126, hazard ratio 0.324, standard error (SE) 0.4698, p = 0.017) and increased miR-195 (β-coefficient 1.442, hazard ratio 4.229, SE 0.446, p = 0.001) predicted time to disease recurrence. Survival regression trees analysis illustrated a relative cut-off of ≤0.488 for miR-195 and a relative cut-off of >−0.218 for miR-135b; both were associated with improved disease recurrence (p < 0.001, p = 0.015). Using multivariable analysis with all targets as predictors, miR-195 (β-coefficient 3.187, SE 1.419, p = 0.025) was the sole significant independent predictor of recurrence. Conclusion: MiR-195 has strong value in predicting time to recurrence in CRC patients. Additionally, miR-21 and miR-135b predict the degree nodal burden. Future studies may include these findings to personalize therapeutic and surgical decision making.

Reactive Oxygen Species-Mediated Diabetic Heart Disease: Mechanisms and Therapies

Significance: Diabetic heart disease (DHD) is the primary cause of mortality in people with diabetes. A significant contributor to the development of DHD is the disruption of redox balance due to reactive oxygen species (ROS) overproduction resulting from sustained high glucose levels. Therapies specifically focusing on the suppression of ROS will hugely benefit patients with DHD. Recent Advances: In addition to the gold standard pharmacological therapies, the recent development of gene therapy provides an exciting avenue for developing new therapeutics to treat ROS-mediated DHD. In particular, microRNAs (miRNAs) are gaining interest due to their crucial role in several physiological and pathological processes, including DHD. Critical Issues: miRNAs have many targets and differential function depending on the environment. Therefore, a proper understanding of the function of miRNAs in specific cell types and cell states is required for the successful application of this technology. In the present review, we first provide an overview of the role of ROS in contributing to DHD and the currently available treatments. We then discuss the newer gene therapies with a specific focus on the role of miRNAs as the causative factors and therapeutic targets to combat ROS-mediated DHD. Future Directions: The future of miRNA therapeutics in tackling ROS-mediated DHD is dependent on a complete understanding of how miRNAs behave in different cells and environments. Future research should also aim to develop conditional miRNA therapeutic platforms capable of switching on and off in response to disruptions in the redox state. Antioxid. Redox Signal. 36, 608-630.

Non-coding RNAs related to angiogenesis in gynecological cancer

Gynecological cancer affects the female reproductive system, including ovarian, uterine, endometrial, cervical, vulvar, and vaginal tumors. Non-coding RNAs (ncRNAs), and in particular microRNAs, function as regulatory molecules, which can control gene expression in a post-transcriptional manner. Normal physiological processes like cellular proliferation, differentiation, and apoptosis, and pathological processes such as oncogenesis and metastasis are regulated by microRNAs. Numerous reports have shown a direct role of microRNAs in the modulation of angiogenesis in gynecological cancer, via targeting pro-angiogenic factors and signaling pathways. Understanding the molecular mechanism involved in the regulation of angiogenesis by microRNAs may lead to new treatment options. Recently the regulatory role of some long non-coding RNAs in gynecological cancer has also been explored, but the information on this function is more limited. The aim of this article is to explore the pathways responsible for angiogenesis, and to what extent ncRNAs may be employed as biomarkers or therapeutic targets in gynecological cancer.

MicroRNA-195 predicts olanzapine response in drug-free patients with schizophrenia: A prospective cohort study

BACKGROUND

Disturbances of microRNA-195 have been implicated in the pathogenesis of schizophrenia. However, microRNA-195 levels in schizophrenia are controversial.

AIMS

To the best of our knowledge, this is the first study to examine microRNA-195 levels in untreated schizophrenia patients and their relationship to olanzapine response.

METHODS

We recruited 81 untreated schizophrenia patients and 96 healthy controls. The patients received 2 months olanzapine treatment. MicroRNA-195 levels in peripheral blood mononuclear cells were measured using quantitative real-time polymerase chain reaction testing. Psychiatric symptoms were assessed using the Positive and Negative Syndrome Scale.

RESULTS

No significant differences in microRNA-195 levels were found between patients and healthy controls (p > 0.05). Olanzapine significantly reduced microRNA-195 levels after 2 months treatment (p = 0.003). Interestingly, microRNA-195 levels decreased significantly in responders (p = 0.010), but not in non-responders (p > 0.05). Both baseline microRNA-195 levels (p = 0.027, p = 0.030) and the reduction rate of microRNA-195 levels (p = 0.034, p = 0.044) were positively associated with the reduction rate of Positive and Negative Syndrome Scale total score and general psychopathological subscale score. Multiple stepwise regression analysis revealed that baseline microRNA-195 level was an independent contributor to the reduction in Positive and Negative Syndrome Scale total score and the general psychopathological subscale score (p = 0.018, p = 0.030). Finally, logistic regression analysis suggested that baseline microRNA-195 level can serve as a biomarker for response to olanzapine (p = 0.037).

CONCLUSIONS

Our data indicate that microRNA-195 level may predict symptomatic improvement and olanzapine response in schizophrenia patients, suggesting that microRNA-195 should be considered as a potential therapeutic target for antipsychotics.

Regulation of microRNA-497 expression in human cancer

MicroRNAs (miRNAs/miRs) are a type of non-coding single-stranded RNA, with a length of ~22 nt, which are encoded by endogenous genes and are involved in the post-transcriptional regulation of gene expression in animals and plants. Studies have demonstrated that miRNAs play an important role in the occurrence, development, metastasis, diagnosis and treatment of cancer. In recent years, miR-497 has been identified as one of the key miRNAs in a variety of cancer types and has been shown to be downregulated in a variety of solid tumors. However, the regulation of miR-497 expression involves a complex network, which is affected by several factors. The aim of the present review was to summarize the mechanism of regulation of miR-497 expression at the pre-transcriptional and transcriptional levels in cancer, as well as the role of miR-497 expression imbalance in cancer diagnosis, treatment and prognosis. The regulatory mechanisms of miR-497 expression may aid in our understanding of the causes of miR-497 expression imbalance and provide a reference value for further research on the diagnosis and treatment of cancer.

Interactions of Vascular Endothelial Growth Factor and p53 with miR-195 in Thyroid Carcinoma: Possible Therapeutic Targets in Aggressive Thyroid Cancers

BACKGROUND

The clinical pathological features, as well as the cellular mechanisms of miR-195, have not been investigated in thyroid carcinoma.

OBJECTIVE

The aim of this study is to identify the interactions of vascular endothelial growth factor (VEGF), p53 and miR-195 in thyroid carcinoma. The clinical and pathological features of miR-195 were also investigated.

METHODS

The expression levels of miR-195 were identified in 123 primary thyroid carcinomas, 40 lymph nodes with metastatic papillary thyroid carcinomas and seven non-neoplastic thyroid tissues (controls) as well as two thyroid carcinoma cell lines, B-CPAP (from metastasizing human papillary thyroid carcinoma) and MB-1 (from anaplastic thyroid carcinoma), by the real-time polymerase chain reaction. Using Western blot and immunofluorescence, the effects of exogenous miR-195 on VEGF-A and p53 protein expression levels were examined. Then, cell cycle and apoptosis assays were performed to evaluate the roles of miR-195 in cell cycle progression and apoptosis.

RESULTS

The expression of miR-195 was downregulated in majority of the papillary thyroid carcinoma tissue as well as in cells. Introduction of exogenous miR-195 resulted in downregulation of VEGF-A and upregulation of p53 protein expressions. Upregulation of miR-195 in thyroid carcinoma cells resulted in cell cycle arrest. Moreover, we demonstrated that miR-195 inhibits cell cycle progression by induction of apoptosis in the thyroid carcinoma cells.

CONCLUSION

Our findings showed for the first time that miR-195 acts as a tumour suppressor and regulates cell cycle progression and apoptosis by targeting VEGF-A and p53 in thyroid carcinoma. The current study exhibited that miR-195 might represent a potential therapeutic target for patients with thyroid carcinomas having aggressive clinical behaviour.

Blood Circulating Exosomes Contain Distinguishable Fractions of Free and Cell-Surface-Associated Vesicles

BACKGROUND

Considering exosomes as intercellular transporters, inevitably interacting with the plasma membrane and the large available surface of blood cells, we wonder if a fraction of circulating exosomes is associated with the surface of blood cells.

OBJECTIVE

The aim of this study was to develop an efficient protocol for isolating exosomes associated with the surface of blood cells and to further investigate the characteristics of this fraction in a healthy state and during the development of breast cancer, as well as its possible implication for use in diagnostic applications.

METHODS

Blood samples were collected from Healthy Females (HFs) and breast cancer patients (BCPs). Exosomes extracted from blood plasma and eluted from the surface of blood cells were isolated by ultrafiltration with subsequent ultracentrifugation.

RESULTS

Transmission Electron Microscopy (TEM), along with immunogold labeling, demonstrated the presence of exosomes among membrane-wrapped extracellular vesicles (EVs) isolated from both plasma and blood cell eluates. TEM, nanoparticle tracking analysis, and NanoOrange protein quantitation data showed that cell-associated exosomes constituted no less than 2/3 of total blood exosome number. Exosomes, ranging from 50-70 nm in size, prevailed in the blood of breast cancer patients, whereas smaller exosomes (30-50 nm) were mostly observed in the blood of healthy women. Analysis of specific proteins and RNAs in exosomes circulating in blood demonstrated the significant differences in the packing density of the polymers in exosomes of HFs and BCPs. Preliminary data indicated that detection of cancer-specific miRNA (miR-103, miR-191, miR-195) in exosomes associated with the fraction of red blood cells allowed to discriminate HFs and BCPs more precisely compared to cell-free exosomes circulating in plasma.

CONCLUSION

Our data provide the basis for using blood cell-associated exosomes for diagnostic applications.

Long Noncoding RNA SNHG12 Indicates the Prognosis and Accelerates Tumorigenesis of Diffuse Large B-Cell Lymphoma Through Sponging microR-195

Background

Small nucleolar RNA host gene 12 (SNHG12) expression is associated with multiple cancers, including renal cell carcinoma, prostate cancer, cervical cancer, nasopharyngeal carcinoma, colorectal cancer, and hepatocellular carcinoma. However, SNHG12 biological function is unclear in diffuse large B-cell lymphoma (DLBCL).

Methods

SNHG12 expression and associated clinicopathological characteristics were evaluated in DLBCL tissues. CCK-8 and transwell assay were used to analyze the in vitro role of SNHG12 in DLBCL progression. The xenograft model was used to explore the in vivo role of SNHG12 in DLBCL growth. The physical interaction between SNHG12 and miR-195 was confirmed using bioinformatics analysis and a dual luciferase assay.

Results

SNHG12 expression was upregulated in DLBCL tissues and correlated with patients’ prognosis. SNHG12 downregulation inhibited cell growth, migration, and invasion of DLBCL cells in vitro, while its overexpression promoted these cellular processes. Moreover, SNHG12 knockdown repressed tumorigenesis of DLBCL cells in vivo. Further experiments demonstrated that miR-195 is a target of SNHG12 in DLBCL and that their expression negatively correlates in DLBCL. SNHG12 functioned as a competing endogenous RNA for miR-195 in DLBCL cells and miR-195 upregulation abolished the effects of SNHG12 on of DLBCL progression.

Conclusion

SNHG12 predicts poor clinical outcome and serves as a novel oncogene in DLBCL via miR-195 sponging. We also suggest that SNHG12 can be used as a potential therapeutic candidate for DLBCL patients.

MiR-195 and miR-497 suppress tumorigenesis in lung cancer by inhibiting SMURF2-induced TGF-β receptor I ubiquitination

SMURF2 is a member of the HECT family of E3 ubiquitin ligases that have important roles as a negative regulator of transforming growth factor‐β (TGF‐β) signaling through ubiquitin‐mediated degradation of TGF‐β receptor I. However, the regulatory mechanism of SMURF2 is largely unknown. In this study, we identified that micro(mi)R‐195 and miR‐497 putatively target SMURF2 using several target prediction databases. Both miR‐195 and miR‐497 bind to the 3′‐UTR of the SMURF2 mRNA and inhibit SMURF2 expression. Furthermore, miR‐195 and miR‐497 regulate SMURF2‐dependent TβRI ubiquitination and cause the activation of the TGF‐β signaling pathway in lung cancer cells. Upregulation of miR‐195 and miR‐497 significantly reduced cell viability and colony formation through the activation of TGF‐β signaling. Interestingly, miR‐195 and miR‐497 also reduced the invasion ability of lung cancer cells when cells were treated with TGF‐β1. Subsequent in vivo studies in xenograft nude mice model revealed that miR‐195 and miR‐497 repress tumor growth. These findings demonstrate that miR‐195 and miR‐497 act as a tumor suppressor by suppressing ubiquitination‐mediated degradation of TGF‐β receptors through SMURF2, and suggest that miR‐195 and miR‐497 are potential therapeutic targets for lung cancer.

MicroRNA-195 as a prognostic factor for cancer survival outcome in China: a meta-analysis

Purpose

MicroRNA-195 is dysregulated in different kinds of cancers and plays a pivotal role in tumorigenesis. It may function as a prognostic biomarker for cancers. However, the results from articles were not consistent. This study was designed to validate the prognostic value of microRNA-195 in human tumors.

Methods

We conducted a detailed search on PubMed until December 31, 2018. The quality of these publications was assessed on the basis of a list of key reviews presented by PRISMA statement. The pooled hazard ratios (HR) and pooled odds ratios (OR) of each 95% confidence interval (95% CI) were calculated to assess the effect.

Results

This meta-analysis included 12 studies involving 940 cancer patients to assess the prognostic value of miR-195 in different solid tumors. The results showed that patients with high expression of miR-195 had favorable tumor-node-metastasis (late vs early: pooled OR =0.16, 95% CI: 0.11–0.22, P<0.001), lymph node metastasis (pooled OR =0.25, 95% CI: 0.18–0.35, P<0.001) and distant metastasis (pooled OR =0.26, 95% CI: 0.13–0.52, P<0.001). At the same time, high levels of miR-195 expression were closely correlated with better overall survival (pooled HR =0.46, 95% CI: 0.36–0.58, P<0.001).

Conclusion

Elevated microRNA-195 may serve as a potential biomarker to predict a favorable prognosis for various cancer types in China.

lncRNA SNHG1 cooperated with miR-497/miR-195-5p to modify epithelial-mesenchymal transition underlying colorectal cancer exacerbation

Our study was intended to provide evidence for whether long noncoding RNA (lncRNA) SNHG1 would accelerate the epithelial-mesenchymal transition (EMT) course intrinsic in colorectal cancer (CRC) by sponging downstream miR-497-5p and miR-195-5p. We altogether collected 338 pairs of CRC and noncancerous tissues, and meanwhile purchased five CRC cell lines (i.e., SW480, HCT116, Lovo, CaCO-2, and HT29) and human embryo intestinal mucosal tissue-sourced cell line (i.e., CCC-HIE-2). The CRC cells as mentioned above were appraised regarding their potencies in proliferation, migration, and invasion, after being transfected with pcDNA3.1-SNHG1, si-SNHG1, miR-195-5p mimic/inhibitor, and miR-497-5p mimic/inhibitor. Eventually, we depended on reverse transcription-polymerase chain reaction to assess SNHG1, miR-497-5p, and miR-195-5p expressions, and the protein levels of EMT-specific molecules were determined on the strength of western blotting. It seemed that there was a high potential for highly expressed SNHG1 and lowly expressed miR-497/miR-195 to symbolize CRC patients' unfavorable prognosis (p < .05). Concurrently, CRC cells were detected with higher SNHG1 expression and lower miR-497/miR-195 expression than CCC-HIE-2 cells (p < .05). In addition, the EMT process of CRC cells was facilitated markedly against the contexts of overexpressed SNHG1 and underexpressed miR-497-5p/miR-195-5p. Intriguingly, the strength of miR-195-5p collaborating with miR-497-5p in affecting the activity of CRC cells seemed to overweigh that of miR-497/miR-195-5p alone. Besides, both miR-195-5p and miR-497-5p were subjected to in vivo and in vitro modification of SNHG1 (p < .05). Conclusively, application of lncRNA SNHG1 for treating CRC might be promising, given its dual modulation of miR-497 and miR-195 underlying CRC pathogenesis.

Construction and analysis of a lncRNA‑miRNA‑mRNA network based on competitive endogenous RNA reveals functional lncRNAs in diabetic cardiomyopathy

Diabetic cardiomyopathy (DCM) is a major cause of mortality in patients with diabetes, particularly those with type 2 diabetes. Long non‑coding RNAs (lncRNAs), including terminal differentiation‑induced lncRNA (TINCR), myocardial infarction‑associated transcript (MIAT) and H19, serve a key role in the regulation of DCM. MicroRNAs (miRNAs/miRs) can inhibit the expression of mRNA at the post‑transcriptional level, whereas lncRNAs can mask the inhibitory effects of miRNAs on mRNA. Together, miRNAs and lncRNAs form a competitive endogenous non‑coding RNA (ceRNA) network that regulates the occurrence and development of various diseases. However, the regulatory role of lncRNAs in DCM is unclear. In this study, a background network containing mRNAs, miRNAs and lncRNAs was constructed using starBase and a regulatory network of DCM was screened using Cytoscape. A functional lncRNA, X‑inactive specific transcript (XIST), was identified in the disease network and the main miRNAs (miR‑424‑5p and miR‑497‑5p) that are regulated by XIST were further screened to obtain the ceRNA regulatory network of DCM. In conclusion, the results of this study revealed that lncRNAs may serve an important role in DCM and provided novel insights into the pathogenesis of DCM.

MicroRNA-195: a review of its role in cancers

MicroRNAs (miRNAs) are small and highly conserved noncoding RNAs that regulate gene expression at the posttranscriptional level by binding to the 3′-UTR of target mRNAs. Recently, increasing evidence has highlighted their profound roles in various pathological processes, including human cancers. Deregulated miRNAs function as either oncogenes or tumor suppressor genes in multiple cancer types. Among them, miR-195 has been reported to significantly impact oncogenicity in various neoplasms by binding to critical genes and signaling pathways, enhancing or inhibiting the progression of cancers. In this review, we focus on the expression of miR-195 in regulatory mechanisms and tumor biological processes and discuss the future potential therapeutic implications of diverse types of human malignancies.

Regulatory effect of miR-195 in the placental dysfunction of preeclampsia

Purpose: Preeclampsia (PE) is a pregnancy specific disease soon after 20 weeks of gestation where major symptoms are hypertension and proteinuria. The underlying pathology is believed to be abnormal placentation. Epigenetic and genetic factors have significant roles in abnormal placental development. MicroRNA's (miRNAs), being one of the most important epigenetic regulators, take part in abnormal placentation. Hsa-miR-195 is a molecule associated with abnormal placental growth mechanisms such as impaired cellular proliferation, inadequate trophoblastic invasion causing defective spiral artery remodeling, and apoptosis. We aimed to evaluate miRNA functions, namely miR-195 expression profile, in order to divulge PE pathogenesis.Methods: In this study, we extracted circulating miRNAs from maternal plasma and placenta from 20 PE patients and 20 normotensive pregnant women. miR-195 was quantified using quantitative real time reverse transcriptase PCR (qRT-PCR). The target genes of miR-195 were predicted by Diana Tools-mirPath, TargetScan, and miRDB databases.Results: We found that miR-195 levels were downregulated (3.83-fold decrease, p < .05) in preeclamptic placenta samples, however miR-195 were undetected in preeclamptic and normotensive plasma samples. The steep down-regulation of miR-195 points to its importance of PE pathogenesis.Conclusion: miR-195 is suggested to regulate PE via its target genes manipulating biological processes such as placental proliferation, apoptosis, and angiogenesis. We propose that detection of decreased miR-195 levels in preeclamptic placentas could be used to enlighten the pathophysiology of PE.

Expression of tumor suppressors miR-195 and let-7a as potential biomarkers of invasive breast cancer

OBJECTIVE

MicroRNAs (miRNAs) are small non-coding RNAs that regulate gene expression at the posttranscriptional level. Some miRNAs, including let-7a and miR-195, have been described as tumor suppressors. However, the roles of these microRNAs in breast cancer progression remain controversial. The aim of this study is to evaluate miR-195 and let-7a expression as potential biomarkers of invasive breast cancer.

METHODS

In the present study, 200 individuals were separated into three groups: (i) 72 women constituting the control group who were selected according to rigorous and well-established criteria; (ii) 56 patients with benign breast tumors; and (iii) 72 patients with malignant breast cancers of different clinical stages. The miR-195 and let-7a expression levels in serum were evaluated by real-time PCR. The results were assessed alone and in combination, and the analysis included an estimation of sensitivity and specificity in ROC curves.

RESULTS

Compared with the benign and control groups, both microRNAs were downregulated in the malignant breast cancer patient group. Compared with the malignant group, the combination of both biomarkers in the control and benign groups showed good sensitivity and specificity in the serum with AUCs of 0.75 and 0.72, respectively. The biomarker combination for the control group versus the malignant group exhibited a better sensitivity and specificity than for the benign group versus the malignant group.

CONCLUSION

These findings support the evidence that the analysis of miR-195 and let-7a can be used as a non-invasive biomarker for breast cancer detection.

Integrated analysis of colorectal cancer microRNA datasets: identification of microRNAs associated with tumor development

Colorectal cancer (CRC) is one of the leading cause of cancer death worldwide. Currently, no effective early diagnostic biomarkers are available for colorectal carcinoma. Therefore, there is a need to discover new molecules able to identify pre-cancerous lesions. Recently, microRNAs (miRNAs) have been associated with the onset of specific pathologies, thus the identification of miRNAs associated to colorectal cancer may be used to detect this pathology at early stages. On these bases, the expression levels of miRNAs were analyzed to compare the miRNAs expression levels of colorectal cancer samples and normal tissues in several miRNA datasets. This analysis revealed a group of 19 differentially expressed miRNAs. To establish the interaction between miRNAs and the most altered genes in CRC, the mirDIP gene target analysis was performed in such group of 19 differentially expressed miRNAs. To recognize miRNAs able to activate or inhibit genes and pathways involved in colorectal cancer development DIANA-mirPath prediction analysis was applied. Overall, these analyses showed that the up-regulated hsa-miR-183-5p and hsa-miR-21-5p, and the down-regulated hsa-miR-195-5p and hsa-miR-497-5p were directly related to colorectal cancer through the interaction with the Mismatch Repair pathway and Wnt, RAS, MAPK, PI3K, TGF-β and p53 signaling pathways involved in cancer development.

Role of miR-195 in cigarette smoke-induced chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is regarded as a persistent respiratory symptom, mainly caused by cigarette smoking. Recent data have suggested that some miRNAs are involved in the pathogenesis of COPD. Here, we found that miR-195 was significantly upregulated in the lung tissues of patients with COPD compared to in never smokers. miR-195 expression was also upregulated in cigarette smoke (CS)-exposed mice. Lentivirus-mediated knockdown of miR-195 alleviated CS-induced lung pathological changes and reduced inflammatory cell infiltration as well as production of interleukin-6 and tumor necrosis factor-α in bronchoalveolar lavage fluid. Mechanically, a positive correlation was found between miR-195 and phosphorylation of Akt in lung tissues of COPD patients. PHLPP2 was confirmed as a direct downstream target of miR-195 and negative regulator of miR-195 expression. Inhibition of PHLPP2 enhanced Akt phosphorylation and increased interleukin-6 and tumor necrosis factor-α production in BEAS-2B cells, resembling the effects of miR-195 overexpression. Collectively, our data indicate that miR-195 has a pathogenetic role in CS-induced COPD and regulates Akt signaling by suppressing PHLPP2 expression. miR-195 may be an effective therapeutic target in COPD.

MicroRNA-195 acts as an anti-proliferative miRNA in human melanoma cells by targeting Prohibitin 1

Background

Melanoma is the most lethal type of skin cancer. Since chemoresistance is a significant barrier, identification of regulators affecting chemosensitivity is necessary in order to create new forms of intervention. Prohibitin 1 (PHB1) can act as anti-apoptotic or tumor suppressor molecule, depending on its subcellular localization. Our recent data shown that accumulation of PHB1 protects melanoma cells from chemotherapy-induced cell death. Lacking of post-transcriptional regulation of PHB1 could explain this accumulation. Interestingly, most of melanoma patients have down-regulation of microRNA-195. Here, we investigate the role of miR-195, its impact on PHB1 expression, and on chemosensitivity in melanoma cells.

Methods

TCGA-RNAseq data obtained from 341 melanoma patient samples as well as a panel of melanoma cell lines were used in an expression correlation analysis between PHB1 and predicted miRNAs. miR-195 impact on PHB1 mRNA and protein levels and relevance of this regulation were investigated in UACC-62 and SK-MEL-5 melanoma lines by RT-qPCR and western blot, luciferase reporter and genetic rescue experiments. Cell proliferation, cell-cycle analysis and caspase 3/7 assay were performed to investigate the potential action of miR-195 as chemosensitizer in melanoma cells treated with cisplatin and temozolomide.

Results

Analysis of the TCGA-RNAseq revealed a significant negative correlation (Pearson) between miR-195 and PHB1 expression. Moreover, RT-qPCR data showed that miR-195 is down-regulated while PHB1 is up-regulated in a collection of melanoma cells. We demonstrated that miR-195 regulates PHB1 directly by RT-qPCR and western blot in melanoma cells and luciferase assays. To establish PHB1 as a relevant target of miR-195, we conducted rescue experiments in which we showed that PHB1 transgenic expression could antagonize the suppressive effect miR-195 on the proliferation of melanoma cells. Finally, transfection experiments combined with drug treatments performed in the UACC-62 and SK-MEL-5 melanoma cells corroborated miR-195 as potential anti-proliferative agent, with potential impact in sensitization of melanoma cell death.

Conclusions

This study support the role of miR-195 as anti-proliferative miRNA via targeting of PHB1 in melanoma cells.

Electronic supplementary material

The online version of this article (10.1186/s12885-017-3721-7) contains supplementary material, which is available to authorized users.

Insulin Receptor Isoforms in Physiology and Disease: An Updated View

The insulin receptor (IR) gene undergoes differential splicing that generates two IR isoforms, IR-A and IR-B. The physiological roles of IR isoforms are incompletely understood and appear to be determined by their different binding affinities for insulin-like growth factors (IGFs), particularly for IGF-2. Predominant roles of IR-A in prenatal growth and development and of IR-B in metabolic regulation are well established. However, emerging evidence indicates that the differential expression of IR isoforms may also help explain the diversification of insulin and IGF signaling and actions in various organs and tissues by involving not only different ligand-binding affinities but also different membrane partitioning and trafficking and possibly different abilities to interact with a variety of molecular partners. Of note, dysregulation of the IR-A/IR-B ratio is associated with insulin resistance, aging, and increased proliferative activity of normal and neoplastic tissues and appears to sustain detrimental effects. This review discusses novel information that has generated remarkable progress in our understanding of the physiology of IR isoforms and their role in disease. We also focus on novel IR ligands and modulators that should now be considered as an important strategy for better and safer treatment of diabetes and cancer and possibly other IR-related diseases.

miR-497 accelerates oxidized low-density lipoprotein-induced lipid accumulation in macrophages by repressing the expression of apelin

microRNAs (miRNAs) play important roles in the pathogenesis of atherosclerosis. A previous study has reported that miR-497 is elevated in advanced atherosclerotic lesions in an apoE-deficient (apoE-/-) mouse model. The purpose of this study is to test whether miR-497 can modulate macrophage foam cell formation, an initiating event in atherosclerosis. We found that miR-497 was upregulated in THP-1 macrophages after treatment with oxidized low-density lipoprotein (oxLDL). Enforced expression of miR-497 promoted lipid accumulation and decreased cholesterol efflux in oxLDL-exposed THP-1 macrophages. In contrast, downregulation of miR-497 suppressed oxLDL-induced lipid accumulation in THP-1 macrophages. Apelin was identified to be a downstream target of miR-497. Overexpression of miR-497 significantly reduced the expression of apelin in THP-1 macrophages. Interestingly, delivery of a miR-497-resistant variant of apelin significantly inhibited lipid accumulation and enhanced cholesterol efflux in miR-497-overexpressing THP-1 macrophages in response to oxLDL. In addition, miR-497 expression was increased and negatively correlated with apelin protein expression in human atherosclerotic lesions. In conclusion, miR-497 contributes to oxLDL-induced lipid deposition in macrophages largely via targeting of apelin and thus represents a potential therapeutic target for atherosclerosis.

MicroRNA-195 inhibits the behavior of cervical cancer tumors by directly targeting HDGF

MicroRNAs (miRNAs/miRs) are a class of conserved non-coding endogenous small regulatory RNAs that regulate target gene expression by binding to the 3′-untranslated region of target mRNAs in a base-pairing manner, resulting in repression of transcription or degradation of target mRNAs. It has been demonstrated previously that the abnormal expression of miRNAs is involved in the carcinogenesis and progression of cervical cancer. The aim of the present study was to investigate the expression, biological functions and underlying molecular mechanisms of miR-195 in cervical cancer. The reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was used to detect the expression level of miR-195 in cervical cancer tissues and cell lines. Following transfection, an MTT assay, cell migration and invasion assays, western blot analysis and a dual-luciferase reporter assay were performed in human cervical cancer cells. In the present study, it was identified that miR-195 was downregulated in cervical cancer tissues and cell lines. Additionally, upregulation of miR-195 and knockdown of hepatoma-derived growth factor (HDGF) inhibited proliferation, migration and invasion of cervical cancer cells. Furthermore, a dual-luciferase reporter assay identified that HDGF was a direct target gene of miR-195. RT-qPCR and western blot analysis demonstrated that miR-195 mimic inhibited HDGF expression at the mRNA and protein levels, whereas miR-195 inhibitor enhanced HDGF expression at the mRNA and protein levels. These results indicated that miR-195 targeted HDGF to inhibit the behavior of tumors in cervical cancer. These results also suggested that miR-195 was a potential therapeutic biomarker of cervical cancer.

Low tissue levels of miR-125b predict malignancy in solitary fibrous tumors of the pleura

Background

Solitary fibrous tumors of the pleura (SFTP) are rare neoplasia of the chest. A subset of SFTP follows a malignant course, sometimes several years after complete resection. Traditional scoring systems based on clinical and histological features are poor predictors of biological behavior. This study aimed to investigate tumor-associated miRNAs expression as novel biomarkers to predict the clinical behavior of SFTP.

Methods

Formalin-fixed and paraffin-embedded SFTP tissues blocks from patients surgically resected between 1992 and 2013 at two tertiary care teaching hospitals were included. SFTP tumors were categorized as either malignant or benign variants according to the WHO classification. Following miRNAs levels were measured: let-7a, miR-16b, miR-17, miR-21, miR-31, miR-34a, miR-92a, miR-125a, miR-125b, miR-195-5b, miR-203a, and miR-223. Differential gene expressions which were calculated with the threshold cycle (C_t) method were compared among the two variants.

Results

Thirty-eight patients (40% male, mean age 62.2 (±10.9) years) were included. Expression levels of miR-125b showed a significant difference between benign compared to malignant variants (−3.08 ± 0.93 vs. -2.22 ± 1.36, p = 0.0068). Furthermore, lower levels of miR-125b were found to be associated with increased tumor size (p = 0.0414). Thus, downregulation of miR-125b indicates malignant transformation. All other investigated miRNAs were not associated with grading of SFTP.

Conclusions

Our data suggest a potential role of miR-125b in the pathogenesis of tumor growth and malignant transformation of SFTP, respectively. Further studies have to address the potential use of miRNA-125b as a biomarker or therapeutic target in SFTP.

MicroRNA-497 impairs the growth of chemoresistant neuroblastoma cells by targeting cell cycle, survival and vascular permeability genes

Despite multimodal therapies, a high percentage of high-risk neuroblastoma (NB) become refractory to current treatments, most of which interfere with cell cycle and DNA synthesis or function, activating the DNA damage response (DDR). In cancer, this process is frequently altered by deregulated expression or function of several genes which contribute to multidrug resistance (MDR). MicroRNAs are outstanding candidates for therapy since a single microRNA can modulate the expression of multiple genes of the same or different pathways, thus hindering the development of resistance mechanisms by the tumor. We found several genes implicated in the MDR to be overexpressed in high-risk NB which could be targeted by microRNAs simultaneously. Our functional screening identified several of those microRNAs that reduced proliferation of chemoresistant NB cell lines, the best of which was miR-497. Low expression of miR-497 correlated with poor patient outcome. The overexpression of miR-497 reduced the proliferation of multiple chemoresistant NB cell lines and induced apoptosis in MYCN-amplified cell lines. Moreover, the conditional expression of miR-497 in NB xenografts reduced tumor growth and inhibited vascular permeabilization. MiR-497 targets multiple genes related to the DDR, cell cycle, survival and angiogenesis, which renders this molecule a promising candidate for NB therapy.

miR-497 expression, function and clinical application in cancer

MicroRNAs (miRNAs) are small non-coding RNAs that inhibit gene expression by binding to the 3' untranslated region (3'-UTR) of their target mRNAs. Recent studies show that miR-497 plays an important role in various cancers. Here, we summarize the existing studies of miR-497 as following: (1) miR-497 expression in cancer; (2) regulation mechanisms of miR-497 expression; (3) function of miR-497 in cancer; (4) direct targets of miR-497; (5) Clinical applications of miR-497. Recent analyses verify that miR-497 mainly suppresses tumors; however, it also acts as an oncogene in several cancers. Increasing evidence indicates that miR-497 can serve as a diagnostic and prognostic biomarker and is a promising therapeutic target for future clinical applications.

Specific MicroRNAs Differentiate Adrenocortical Adenomas from Carcinomas and Correlate With Weiss Histopathologic System

MicroRNAs (miRs) play a central role in regulating gene expression and are strongly associated with cancer development. This study sought to determine if adrenocortical carcinomas can be differentiated from adenomas by their miR profiles and to correlate the findings with the histologic Weiss system for identifying malignancy in adrenocortical tumors (ACTs). Forty-six primary and 2 recurrent ACTs retrieved from the files of the pathology department of a tertiary medical center were evaluated blindly for the Weiss criteria. High-quality RNA was extracted, and miR expression was evaluated with microarrays and quantitative reverse-transcriptase polymerase chain reaction. The Weiss system defined 17 tumors as carcinomas and 29 as adenomas. On microarray analysis, over a dozen miRs were upregulated or downregulated in carcinomas compared with adenomas. Upregulation of miR-503 was the best single discriminator of malignancy. The combination of miR-34a and miR-497 underexpression discriminated carcinomas from adenomas with 100% sensitivity and 96% specificity. Statistical analysis revealed a high level of correspondence between the Weiss system and miR expression. In conclusion, miR expression can accurately identify malignant ACTs with equal efficiency to the Weiss system. miR analysis may have added value in tumors with borderline features that are difficult to interpret histopathologically.

Experimental evidences for hsa-miR-497-5p as a negative regulator of SMAD3 gene expression

The SMAD family comprises of transcription factors that function as signal transducers of transforming growth factor (TGFβ) superfamily members. MiRNAs are a class of small noncoding RNAs that may play a major role in post transcriptional regulation of SMAD genes. Here, we intended to investigate if hsa-miR-497-5p is capable of regulating SMAD3 gene expression. Hsa-miR-497-5p was bioinformatically predicted as a candidate regulator of SMAD3 gene expression and then, hsa-miR-497-5p expression status was analyzed in different cell lines using RT-qPCR. Overexpression of hsa-miR-497-5p in HEK293t cells resulted in downregulation of SMAD3 which was detected by RT-qPCR and western analysis. Further, dual luciferase assay results supported direct interaction of hsa-miR-497-5p with 3'-UTR sequences of SMAD3 transcript. Overexpression of hsa-miR-497-5p in HEK293t cells resulted in cell cycle arrest in G0/G1 phase, detected by flow cytometry. Overall, accumulative results indicated that hsa-miR-497-5p by targeting SMAD3 is potentially one of the regulators of the TGFβ signaling pathway.

Upregulation of miR-497 induces hepatic insulin resistance in E3 rats with HFD-MetS by targeting insulin receptor

OBJECTIVE

The study aims to find regulatory microRNA(s) responsible for down-regulated insulin receptor (InsR) in the liver of HFD-MetS E3 rats with insulin resistance.

METHODS

Firstly, hepatic insulin resistance in HFD-MetS E3 rats was evaluated by RT-qPCR, western blotting, immunohistochemistry and PAS staining. Secondly, the candidate miRNAs targeting rat InsR were predicted through online softwares and detected in the liver of HFD-MetS E3 rats with insulin resistance. Then, the expression of InsR, phosphorylated IRS-1 (pIRS-1) at Tyr632, phosphorylated AKTs (pAKTs) at Ser473 and Thr308, phosphorylated GSK-3β (p GSK-3β) at Ser9, phosphorylated GS (pGS) at Ser641 and the glycogen content were detected in CBRH-7919 cells treated with 100 nM insulin for different time periods by western blotting or PAS staining respectively, after transient transfection with miR-497 mimics or inhibitors for 24 h. Lastly, the relation between miR-497 and InsR was further determined using dual luciferase reporter assay.

RESULTS

Elevated miR-497 was negatively related with down-regulated InsR in the liver of HFD-MetS E3 rats with insulin resistance. Comparing with the mNC group, glycogen content and the expression of InsR, pIRS-1 (Tyr632), pAKTs (Ser473 and Thr308) and pGSK-3β (Ser9) decreased significantly in CBRH-7919 cells, while pGS (Ser641) increased significantly, after transient transfection with miR-497 mimics for 24 h and treatment with 100 nM insulin for corresponding time periods, counter to those results in CBRH-7919 cells after similar procedures with miR-497 inhibitors and insulin. In addition, dual luciferase reporter assay further confirmed that miR-497 can bind to the 3'UTR of rat InsR.

CONCLUSION

Insulin receptor is the target gene of miR-497, and elevated miR-497 might induce hepatic insulin resistance in HFD-MetS E3 Rats through inhibiting the expression of insulin receptor and confining the activation of IRS-1/PI3K/Akt/GSK-3β/GS pathway to insulin.

Bias in microRNA functional enrichment analysis

MOTIVATION

Many studies have investigated the differential expression of microRNAs (miRNAs) in disease states and between different treatments, tissues and developmental stages. Given a list of perturbed miRNAs, it is common to predict the shared pathways on which they act. The standard test for functional enrichment typically yields dozens of significantly enriched functional categories, many of which appear frequently in the analysis of apparently unrelated diseases and conditions.

RESULTS

We show that the most commonly used functional enrichment test is inappropriate for the analysis of sets of genes targeted by miRNAs. The hypergeometric distribution used by the standard method consistently results in significant P-values for functional enrichment for targets of randomly selected miRNAs, reflecting an underlying bias in the predicted gene targets of miRNAs as a whole. We developed an algorithm to measure enrichment using an empirical sampling approach, and applied this in a reanalysis of the gene ontology classes of targets of miRNA lists from 44 published studies. The vast majority of the miRNA target sets were not significantly enriched in any functional category after correction for bias. We therefore argue against continued use of the standard functional enrichment method for miRNA targets.

Roles of miR-497 and its potential signaling pathway in diseases and with vascular endothelial growth factor

MicroRNA (miRNA) is a class of small endogenous non-coding RNAs that are ∼ 22 nucleotides in length and can have structural, enzymatic and post-transcriptional regulators of gene expression targeting mRNA for translational repression and/or degradation. miR-497 is high on the list of noncoding, small, regulatory RNAs that plays important roles in the pathogenesis of some diseases and takes part in some signaling pathways in some diseases, but many questions await answers. Vascular endothelial growth factor (VEGF) is a notable chemokine that plays critical roles in angiogenesis and vasculogenesis. There might be an association between miRNA-497 and VEGF. This review was performed to sum up the roles of miR-497 and its potential signaling pathway in diseases and with VEGF.

A novel serum microRNA panel to discriminate benign from malignant ovarian disease

Ovarian cancer is the seventh most common cancer in women and the most frequent cause of gynaecological malignancy-related mortality in women. Currently, no standardized reliable screening test exists. MicroRNA profiling has allowed the identification of signatures associated with diagnosis, prognosis and response to treatment of human tumours. The aim of this study was to determine if a microRNA signature could distinguish between malignant and benign ovarian disease. A training set of 5 serous ovarian carcinomas and 5 benign serous cystadenomas were selected for the initial experiments. The validation set included 20 serous ovarian carcinomas and 20 benign serous cystadenomas. The serum/plasma focus microRNA Exiqon panel was used for the training set. For the validation set a pick and mix Exiqon panel, which focuses on microRNAs of interest was used. A panel of 4 microRNAs (let-7i-5p, miR-122, miR-152-5p and miR-25-3p) was significantly down regulated in cancer patients. These microRNAs target WNT signalling, AKT/mTOR and TLR-4/MyD88, which have previously been found to play a role in ovarian carcinogenesis and chemoresistance. let-7i-5p, miR-122, miR-152-5p and miR-25-3p could act as diagnostic biomarkers in ovarian cancer.

MicroRNA-497 suppresses angiogenesis by targeting vascular endothelial growth factor A through the PI3K/AKT and MAPK/ERK pathways in ovarian cancer

MicroRNAs (miRNAs) have been shown to play an important role in diverse biological processes and cancer progression. The objective of the present study was to investigate the role of miR-497 in ovarian cancer angiogenesis. We found that miR-497 expression was downregulated in human ovarian cancer tissues, and the low miR-497 expression was significantly associated with increased angiogenesis. Functionally, exogenous expression of miR-497 suppressed the ability of ovarian cancer cells to promote capillary tube formation of endothelial cells. We further disclosed that miR-497 exerted its function of anti-angiogenesis by suppressing VEGFA expression in ovarian cancer cells and, in turn, impairing the VEGFR2-mediated PI3K/AKT and MAPK/ERK pathways. Our findings suggest that downregulation of miR-497 may contribute to angiogenesis in ovarian cancer. miR-497 may be a promising candidate target for prevention and treatment of ovarian cancer.

MicroRNA-497 inhibition of ovarian cancer cell migration and invasion through targeting of SMAD specific E3 ubiquitin protein ligase 1

Ovarian cancer is the leading cause of death from gynecological malignancies worldwide. Understanding the molecular mechanism underlying ovarian cancer progression facilitates the development of promising strategy for ovarian cancer therapy. Previously, we observed frequent down-regulation of miR-497 expression in ovarian cancer tissues. In this study, we investigated the role of miR-497 in ovarian cancer metastasis. We found that endogenous miR-497 expression was down-regulated in the more aggressive ovarian cancer cell lines compared with the less aggressive cells. Exogenous expression of miR-497 suppressed ovarian cancer cell migration and invasion, whereas reduction of endogenous miR-497 expression induced tumor cell migration and invasion. Mechanistic investigations confirmed pro-metastatic factor SMURF1 as a direct target of miR-497 through which miR-497 ablated tumor cell migration and invasion. Further studies revealed that lower levels of miR-497 expression were associated with shorter overall survival as well as increased SMURF1 expression in ovarian cancer patients. Our results indicate that down-regulation of miR-497 in ovarian cancer may facilitate tumor metastasis. Restoration of miR-497 expression may be a promising strategy for ovarian cancer therapy.

MicroRNA-195 inhibits non-small cell lung cancer cell proliferation, migration and invasion by targeting MYB

MicroRNA-195 (miR-195) has been implicated in several other cancers; however, its role in non-small cell lung cancer (NSCLC) remains unclear. In this study, we demonstrated that miR-195 was significantly down-regulated in NSCLC samples and cell lines compared with corresponding normal counterparts. In vitro and in vivo functional assays demonstrated that modulation of miR-195 expression affected NSCLC cell proliferation, migration and invasion. Using miRNA target prediction algorithms and reporter assays, we demonstrated that miR-195 suppressed the expression of MYB both at the mRNA and protein level, and was directly bound to the 3'untranslated region of MYB mRNA. Overexpression of MYB in NSCLC cells using an ectopic expression vector restored the decreased cell proliferation, migration and invasion effects induced by miR-195. Finally, we observed an inverse correlation between MYB and miR-195 in NSCLC. Taken together, our findings indicated that miR-195 functions as tumour suppressor in NSCLC, and the miR-195/MYB axis might represent a potential therapeutic target for NSCLC intervention.

Clinical and functional impact of TARBP2 over-expression in adrenocortical carcinoma

Deregulation of microRNA (miRNA) expression in adrenocortical carcinomas (ACCs) has been documented to have diagnostic, prognostic, as well as functional implications. Here, we evaluated the mRNA expression of DROSHA, DGCR8, DICER (DICER1), TARBP2, and PRKRA, the core components in the miRNA biogenesis pathway, in a cohort of 73 adrenocortical tumors (including 43 adenomas and 30 carcinomas) and nine normal adrenal cortices using a RT-qPCR approach. Our results show a significant over-expression of TARBP2, DICER, and DROSHA in the carcinomas compared with adenomas or adrenal cortices (P<0.001 for all comparisons). Using western blot and immunohistochemistry analyses, we confirmed the higher expression of TARBP2, DICER, and DROSHA at the protein level in carcinoma cases. Furthermore, we demonstrate that mRNA expression of TARBP2, but not DICER or DROSHA, is a strong molecular predictor to discriminate between adenomas and carcinomas. Functionally, we showed that inhibition of TARBP2 expression in human NCI-H295R ACC cells resulted in a decreased cell proliferation and induction of apoptosis. TARBP2 over-expression was not related to gene mutations; however, copy number gain of the TARBP2 gene was observed in 57% of the carcinomas analyzed. In addition, we identified that miR-195 and miR-497 could directly regulate TARBP2 and DICER expression in ACC cells. This is the first study to demonstrate the deregulation of miRNA-processing factors in adrenocortical tumors and to show the clinical and biological impact of TARBP2 over-expression in this tumor type.

Epigenetic silencing of monoallelically methylated miRNA loci in precancerous colorectal lesions

Epigenetic silencing of protein-encoding genes is common in early-stage colorectal tumorigenesis. Less is known about the methylation-mediated silencing of genes encoding microRNAs (miRNAs), which are also important epigenetic modulators of gene expression. Using quantitative PCR, we identified 56 miRNAs that were expressed in normal colorectal mucosa and in HT29 colorectal cancer cells treated with demethylating agents but not in untreated HT29 cells, suggesting that they probably undergo methylation-induced silencing during colorectal tumorigenesis. One of these, miR-195, had recently been reported to be underexpressed in colorectal cancers and to exert tumor-suppressor effects in colorectal cancer cells. We identified the transcription start site (TSS) for primary miRNA (pri-miR)-497/195, the primary precursor that yields miR-195 and another candidate on our list, miR-497, and a single CpG island upstream to the TSS, which controls expression of both miRNAs. Combined bisulfite restriction analysis and bisulfite genomic sequencing studies revealed monoallelic methylation of this island in normal colorectal mucosa (50/50 samples) and full methylation in most colorectal adenomas (38/50; 76%). The hypermethylated precancerous lesions displayed significantly downregulated expression of both miRNAs. Similar methylation patterns were observed at two known imprinted genes, MEG3 and GNAS-AS1, which encode several of the 56 miRNAs on our list. Imprinting at these loci was lost in over half the adenomas (62% at MEG3 and 52% at GNAS-AS1). Copy-number alterations at MEG3, GNAS-AS1 and pri-miR-497/195, which are frequent in colorectal cancers, were less common in adenomas and confined to tumors displaying differential methylation at the involved locus. Our data show that somatically acquired, epigenetic changes at monoallelically methylated regions encoding miRNAs are relatively frequent in sporadic colorectal adenomas and might contribute to the onset and progression of these tumors.

The tumor-suppressive miR-497-195 cluster targets multiple cell-cycle regulators in hepatocellular carcinoma

MicroRNAs (miRNAs) are key post-transcriptional regulators of gene expression and commonly deregulated in carcinogenesis. To explore functionally crucial tumor-suppressive (TS)-miRNAs in hepatocellular carcinoma (HCC), we performed integrative function- and expression-based screenings of TS-miRNAs in six HCC cell lines. The screenings identified seven miRNAs, which showed growth-suppressive activities through the overexpression of each miRNA and were endogenously downregulated in HCC cell lines. Further expression analyses using a large panel of HCC cell lines and primary tumors demonstrated four miRNAs, miR-101, -195, -378 and -497, as candidate TS-miRNAs frequently silenced in HCCs. Among them, two clustered miRNAs miR-195 and miR-497 showed significant growth-suppressive activity with induction of G1 arrest. Comprehensive exploration of their targets using Argonute2-immunoprecipitation-deep-sequencing (Ago2-IP-seq) and genome-wide expression profiling after their overexpression followed by pathway analysis, revealed a significant enrichment of cell cycle regulators. Among the candidates, we successfully identified CCNE1, CDC25A, CCND3, CDK4, and BTRC as direct targets for miR-497 and miR-195. Moreover, target genes frequently upregulated in HCC in a tumor-specific manner, such as CDK6, CCNE1, CDC25A and CDK4, showed an inverse correlation in the expression of miR-195 and miR-497, and their targets. These results suggest the molecular pathway regulating cell cycle progression to be integrally altered by downregulation of miR-195 and miR-497 expression, leading to the aberrant cell proliferation in hepatocarcinogenesis.