Role Of miR-210 Research Articles

MiR-182 and miR-135b Mediate the Tumorigenesis and Invasiveness of Colorectal Cancer Cells via Targeting ST6GALNAC2 and PI3K/AKT Pathway.

Metastasis is a leading cause of cancer-related death including colorectal cancer (CRC). MicroRNAs are known to regulate cancer pathways and to be expressed aberrantly in cancer. Aberrant sialylation is closely associated with malignant phenotype of tumor cells, including invasiveness and metastasis. This study aimed to investigate the association of miR-182 and miR-135b with proliferation and invasion by targeting sialyltransferase ST6GALNAC2 in CRC cells and explore the potential molecular mechanism. We measured the levels of miR-182, miR-135b, and ST6GALNAC2 in a series of CRC cell lines and tissues using real-time PCR. Bioinformatics analysis and luciferase reporter assay were performed to test the direct binding of miR-182 and miR-135b to the target gene ST6GALNAC2. We also analyzed the possible role of miR-182/-135b on colony formation, wound healing, invasion, and tube formation. The expression of miR-182 and miR-135b was higher in tumor tissues compared to adjacent noncancerous tissues of CRC patients, as well as up-regulated in SW620 cells than in SW480 cells with different metastatic potential. By applying bioinformatics analysis and luciferase reporter assay, we identified ST6GALNAC2 as the direct target of miR-182/-135b. Furthermore, miR-182/-135b inhibited significantly ST6GALNAC2 expression, and consistently, ST6GALNAC2 mediated migration, adhesion, invasion, proliferation, and tumor angiogenesis in CRC cell lines. Additionally, PI3K/AKT signaling pathway was regulated by miR-182/135b, which was partially blocked by altered level of ST6GALNAC2 in CRC. The miR-182/-135b/ST6GALNAC2/PI3K/AKT axis may serve as a predictive biomarker and a potential therapeutic target in CRC treatment.

MicroRNA-210 Protects PC-12 Cells Against Hypoxia-Induced Injury by Targeting BNIP3.

MicroRNA (miR)-210 is the most consistently and predominantly up-regulated miR in response to hypoxia in multiple cancer cells. The roles of miR-210 in rat adrenal gland pheochromocytoma (PC-12) cells remain unknown. We aimed to explore the possible effect of miR-210 in neonatal brain injury. We explored the potential molecular mechanism by using PC-12 cells under hypoxia. Scramble miRs, miR-210 mimic, miR-210 inhibitor or its negative control were respectively transfected into PC-12 cells. Cell viability, migration, invasion and apoptosis were also assessed to evaluate hypoxia-induced cell injury. The expression level of miR-210 was identified by quantitative real-time polymerase chain reaction (qRT-PCR) analysis. Apoptosis-related protein expression as well as key kinases in the phosphatidylinositol 3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) signal pathway was studied by Western blot analysis. Hypoxia suppressed cell viability, migration and invasion, but promoted apoptosis through activation of mitochondrial- and caspase-dependent pathways. Hypoxia markedly induced up-regulation of miR-210 in PC-12 cells. Overexpression of miR-210 protected PC-12 cells against hypoxia-induced injury. Bcl-2 adenovirus E1B 19 kDa-interacting protein 3 (BNIP3) was proven to be a target gene of miR-210 in PC-12 cells. miR-210 overexpression ameliorated the hypoxia-induced injury in PC-12 cells by down-regulating BNIP3. Hypoxia-induced alterations of key kinases in the PI3K/AKT/mTOR signal pathway were affected by aberrant expression of BNIP3. These findings suggested that miR-210 protected PC-12 cells against hypoxia-induced injury by targeting BNIP3, involving the PI3K/AKT/mTOR signal pathway.

Abstract P268: Overexpression of miR-210 Induces Preeclampsia-like Symptoms in Pregnant Mice by Attenuating the STAT6/IL-4 Pathway

Preeclampsia (PE) is a pregnancy-related hypertensive disorder that affects 5-8% of all pregnancies worldwide. Placental microRNA (miRNA) expression is known to be dysregulated during PE which includes miR-210. However, the role of miR-210 in the development of PE is still unknown. We have previously demonstrated STAT6, a transcription factor, to be a direct target of miR-210. In addition, STAT6 modulates levels of IL-4, an anti-inflammatory cytokine which is known to be beneficial during pregnancy. Given that the STAT6/IL-4 pathway is important for normal pregnancy, we hypothesized that an overexpression of miR-210 in mice will contribute to PE-like symptoms by inhibiting the STAT6/IL-4 pathway. Systolic blood pressures (SBP) were measured using the tail-cuff method on both WT (C57Bl/6J) and miR-210 TG mice. The miR-210 TG mice exhibited increased SBP compared to the WT mice (WT: 95±2 mmHg, miR-210 TG: 115±2.4 mmHg, p<0.05). The miR-210 TG mice also displayed endothelial dysfunction measured by aortic vascular reactivity using wire myography (WT: 93% miR-210 TG: 68% relaxation, p<0.05 vs. WT) and a significant increase in proteinuria (4 fold, p<0.05 vs. WT). Furthermore, the miR-210 TG mice exhibit placental necrosis and a significant increase in the number of malformed pups. Placental STAT6 levels decreased in miR-210 TG compared to WT mice (2.6 fold, p<0.05 vs. WT) as determined by immunoblotting. In addition, qRT-PCR analysis of the miR-210 TG placentas exhibited a (4.8 fold, p<0.05 vs. WT) decrease in IL-4 expression. Immunoblotting and immunohistochemistry (IHC) studies showed a decrease in IL-4 levels (2.4 fold, p<0.05 vs. WT) and immunoreactivity in the miR-210 TG placentas as well as. IHC studies in human placentas also showed a decrease in both IL-4 and STAT6. Based on our results, miR-210 overexpression induces PE-like symptoms including hypertension, endothelial dysfunction, proteinuria, and malformed pups in pregnant mice. In addition, miR-210 overexpression attenuated the STAT6/IL-4 anti-inflammatory pathway. Our data suggests that either targeting miR-210 or the STAT6/1L-4 pathway could be a potential therapeutic in mitigating the symptoms of PE.

The role of miR-210, E2F3 and ephrin A3 in angiosarcoma cell proliferation.

Although angiosarcoma exhibits aggressive progression and is associated with unfavourable prognosis, its pathogenesis is poorly understood. In the present study, we investigated the possibility that microRNAs play a role in the pathogenesis of angiosarcoma. microRNA expression was evaluated by array analysis and real-time PCR, and protein expression was determined by immunohistochemistry and immunoblotting. miR-210 expression was decreased in angiosarcoma cells both in vivo and in vitro. E2F3 and ephrin A3 are putative targets of miR-210, and their protein expression was up-regulated in the tumour cells. Knockdown of E2F3 or ephrin A3 resulted in a significant decrease in the number of angiosarcoma cells. Further investigations into the regulatory mechanisms of oncogenesis associated with miR-210/E2F3/ephrin A3 signalling may lead to a new therapeutic approach against angiosarcoma.

MicroRNA-7 suppresses the homing and migration potential of human endothelial cells to highly metastatic human breast cancer cells

Background:MicroRNA-7 (miR-7) has been observed as a potent tumour suppressor in multiple cancer types including breast cancer. The aim of this study was to investigate the response sensitivities of metastatic breast cancer cells to miR-7 and the roles of miR-7 in the interaction of endothelial cells and metastatic cancer cells.Methods:Expression profile of miRNAs in a breast cancer specimen cohort and breast cancer cells were determined using real-time quantitative miRNA assays. Effect of the altering expression of miR-7 on migration, invasion, proliferation, interaction and underlying molecular mechanism of breast cancer cells and endothelial cells was investigated after treatment with the synthesised mimic of miR-7. Luciferase activity analysis was performed to validate Wave-3 as a novel target of miR-7.Results:miR-7 expression was negatively correlated with the stage, grade and survival of the breast cancer patients. There was also differential expression of miRNAs including miR-7 in the breast cancer cells. The synthesised mimic of miR-7 inhibits the motility and wound healing potential of breast cancer cells. The highly metastatic MDA-MB-231 cells are more sensitive to the miR-7 treatment than the poorly invasive MCF-7 cells. Treatment with miR-7 downregulated the expression of EGFR, IGF1R and Wave3 in MDA-MB-231 cells but not in MCF-7 cells. In addition, we further demonstrated that miR-7 inhibited the proliferation, migration and invasion of endothelial cells. And more importantly, miR-7 suppressed the homing and migration of endothelial cells to more aggressive tumour cell conditions.Conclusions:Given the dual inhibitory effect of miR-7 on metastatic breast cancer cells alone and the interaction of endothelial cells with the tumour-conditioned microenvironment, we suggest miR-7 may be a new therapeutic candidate for its capacity not only to prevent breast cancer cell spreading but also to inhibit tumour-associated angiogenesis in the metastatic breast cancer.

Overexpression of microRNA-495 suppresses the proliferation and invasion and induces the apoptosis of osteosarcoma cells by targeting high-mobility group nucleosome-binding domain 5.

It has been suggested that microRNAs (miRNAs) act as critical regulators in tumorigenesis. MicroRNA-495 (miR-495) has been suggested as a cancer-associated miRNA in various types of cancers; however, the role of miR-495 in osteosarcoma is unknown. The aim of the present study was to determine whether miR-495 is involved in osteosarcoma, and to investigate the potential molecular mechanism of its involvement. We found that miR-495 was significantly downregulated in osteosarcoma tissues and cell lines, as detected by real-time quantitative polymerase chain reaction (RT-qPCR). Overexpression of miR-495 inhibited osteosarcoma cell proliferation in 3-(4,5-dimethylthiazol-2-yl)- ,5-diphenyltetrazolium bromide, colony formation and cell cycle assays. Overexpression of miR-495 induced osteosarcoma cell apoptosis. Moreover, miR-495 overexpression also inhibited osteosarcoma cell invasion. Bioinformatics and luciferase reporter assays demonstrated that miR-495 targets the 3'-untranslated region of high-mobility group nucleosome‑binding domain5 (HMGN5), a potential oncogene in various types of cancers. Overexpression of miR-495 inhibited the expression of HMGN5, cyclinB1, Bcl-2 and matrix metalloproteinase9. In addition, restoration of HMGN5 protein expression abrogated the miR-495-induced effects. Taken together, the present study indicated that miR-495 suppresses the proliferation and invasion and induces the apoptosis of osteosarcoma cells by targeting HMGN5, providing a novel insight into the molecular pathogenesis of osteosarcoma and suggesting a potential molecular target for the development of an miRNA-targeted therapeutic strategy for osteosarcoma.

MiR-202 Promotes Cell Apoptosis in Esophageal Squamous Cell Carcinoma by Targeting HSF2

Esophageal squamous cell carcinoma (ESCC) is one of the most common malignant cancers with high mortality around the world. However, the regulatory mechanism of ESCC carcinogenesis is not completely known. Here we demonstrate the novel role of miR-202 in regulating ESCC cell apoptosis. The analysis of data obtained from the GEO database showed that the expression of miR-202 is aberrantly decreased in tumor tissue from ESCC patients and cultured ESCC cell lines. After transfection with miR-202 mimic or inhibitor, the apoptotic capacity of ESCC cells was significantly increased by miR-202 overexpression but reduced by miR-202 repression. We then identified HSF2 as a direct target of miR-202 with the binding site on the 3′-UTR of HSF2 mRNA in ESCC cells. The apoptosis of ESCC cells induced by the miR-202 mimic could be repressed by HSF2 overexpression. Further studies indicated that HSF2 overexpression strongly upregulated the expression of Hsp70 at both the mRNA and protein levels. In addition, HSF2/Hsp70 suppressed ESCC cell apoptosis by preventing caspase 3 activation. In conclusion, miR-202 is a potential tumor suppressor in human ESCC and acts by regulating the apoptosis of ESCC cells by targeting HSF2, in which caspase 3 activation is involved. This might provide a novel therapeutic target for human ESCC.

MicroRNA-210 induces endothelial cell apoptosis by directly targeting PDK1 in the setting of atherosclerosis

BackgroundAtherosclerosis is a chronically inflammatory disease and one of the leading causes of deaths worldwide. Endothelial cell apoptosis plays a crucial role in its development. Several microRNAs (miRNAs) are reportedly involved in atherosclerotic plaque formation, including miRNA-210 (miR-210). However, the underlying mechanism of its role in endothelial cell apoptosis during atherosclerosis is still largely unknown.MethodsA mouse model with atherosclerosis induced by a high-fat diet (HFD) was built in ApoE (-/-) mice. The levels of endothelial cell apoptosis were determined via flow cytometry. The expressions of miR-210 and PDK1 in purified CD31+ endothelial cells from mouse aorta were measured via RT-qPCR and western blot. Binding between miR-210 and the 3′-untranslated region (UTR) of PDK1 mRNA was predicted using bioinformatics analyses and confirmed with a dual luciferase reporter assay. The effects of miR-210 were further analyzed in an in vitro model using human aortic endothelial cells (HAECs) treated with oxidized low-density lipoprotein (ox-LDL).ResultsWe found that the HFD mice developed atherosclerosis in 12 weeks and had a significantly higher percentage of endothelial cell apoptosis. The upregulated level of miR-210 in the HFD mice and HAECs inversely correlated with the level of PDK1. Inhibiting miR-210 expression significantly reduced HAEC apoptosis, as evidenced by the results of the MTT and flow cytometry experiments. Further analysis identified PDK1 as the target of miR-210 and showed that PDK1 overexpression reversed the pro-apoptotic effect of miR-210 through mediation of the P13K/Akt/mTOR pathways.ConclusionOur study suggests a novel role for miR-210 in the progression of atherosclerosis through the regulation of endothelial apoptosis. This indicates that miR-210 might have potential in treatment of atherosclerosis.

Role of VHL, HIF1A and SDH on the expression of miR-210: Implications for tumoral pseudo-hypoxic fate.

The hypoxia-inducible factor 1α (HIF-1α) and its microRNA target, miR-210, are candidate tumor-drivers of metabolic reprogramming in cancer. Neuroendocrine neoplasms such as paragangliomas (PGLs) are particularly appealing for understanding the cancer metabolic adjustments because of their associations with deregulations of metabolic enzymes, such as succinate dehydrogenase (SDH), and the von Hippel Lindau (VHL) gene involved in HIF-1α stabilization. However, the role of miR-210 in the pathogenesis of SDH-related tumors remains an unmet challenge. Herein is described an in vivo genetic analysis of the role of VHL, HIF1A and SDH on miR-210 by using knockout murine models, siRNA gene silencing, and analyses of human tumors. HIF-1α knockout abolished hypoxia-induced miR-210 expression in vivo but did not alter its constitutive expression in paraganglia. Normoxic miR-210 levels substantially increased by complete, but not partial, VHL silencing in paraganglia of knockout VHL-mice and by over-expression of p76del-mutated pVHL. Similarly, VHL-mutated PGLs, not those with decreased VHL-gene/mRNA dosage, over-expressed miR-210 and accumulate HIF-1α in most tumor cells. Ablation of SDH activity in SDHD-null cell lines or reduction of the SDHD or SDHB protein levels elicited by siRNA-induced gene silencing did not induce miR-210 whereas the presence of SDH mutations in PGLs and tumor-derived cell lines was associated with mild increase of miR-210 and the presence of a heterogeneous, HIF-1α-positive and HIF-1α-negative, tumor cell population. Thus, activation of HIF-1α is likely an early event in VHL-defective PGLs directly linked to VHL mutations, but it is a late event favored but not directly triggered by SDHx mutations. This combined analysis provides insights into the mechanisms of HIF-1α/miR-210 regulation in normal and tumor tissues potentially useful for understanding the pathogenesis of cancer and other diseases sharing similar underpinnings.

MicroRNA -140-5p inhibits colorectal cancer invasion and metastasis by targeting ADAMTS5 and IGFBP5.

BackgroundColorectal cancer (CRC) is one of the most common malignancies in the world. microRNA-140-5p (miR-140) has been shown to be involved in cartilage development and osteoarthritis (OA) pathogenesis. Some contradictions still exist concerning the role of miR-140 in tumor progression and metastasis, and the underlying mechanism is uncertain.MethodsImmunohistochemistry was performed to determine the expressions of ADAMTS5 and IGFBP5 in CRC tissues. Human CRC cell lines HCT116 and RKO were transfected with miR-140 mimic, inhibitor, or small interfering RNA (siRNA) against ADAMTS5 or IGFBP5, respectively, using oligofectamine or lipofectamine 2000. Scratch-wound assay and transwell migration and invasion assays were used to evaluate the effects of miR-140 on the capabilities of migration and invasion. The levels of miR-140 and ADAMTS5 and IGFBP5 mRNA were measured by quantitative real-time polymerase chain reaction (qRT-PCR). Western blot was performed to examine the expression of ADAMTS5 and IGFBP5 proteins.ResultsmiR-140 was significantly reduced, whereas ADAMTS5 and IGFBP5 were upregulated, in the human CRC tissues compared to the corresponding normal colorectal mucosa. miR-140 downregulation and ADAMTS5 or IGFBP5 overexpression were associated with the advanced TNM stage and distant metastasis of CRC. There was a reverse correlation between miR-140 levels and ADAMTS5 and IGFBP5 expression in CRC tissues. ADAMTS5 and IGFBP5 were downregulated by miR-140 at both the protein and mRNA levels in the CRC cell lines. The gain-of- and loss-of-function studies showed that miR-140 inhibited CRC cell migratory and invasive capacities at least partially via downregulating the expression of ADAMTS5 and IGFBP5.ConclusionsThese findings suggest that miR-140 suppresses CRC progression and metastasis, possibly through downregulating ADAMTS5 and IGFBP5. miR-140 might be a potential therapeutic candidate for the treatment of CRC.

Prognostic Value of microRNA-9 in Various Cancers: a Meta-analysis

Recently, there are more and more evidences from studies have revealed the association between microRNA-9 (miR-9) expression and outcome in multiple cancers, but inconsistent results have also been reported. It is necessary to rationalize a meta analysis of all available data to clarify the prognostic role of miR-9. Eligible studies were selected through multiple search strategies and the quality was assessed by MOOSE. Data was extracted from studies according to the key statistics index. All analyses were performed using STATA software. Twenty studies were selected in the meta-analysis to evaluate the prognostic role of miR-9 in multiple tumors. MiR-9 expression level was an independent prognostic biomarker for OS in tumor patients using multivariate and univariate analyses. High expression levels of miR-9 was demonstrated to associated with poor overall survival (OS) (HR = 2.23, 95 % CI: 1.56–3.17, P < 0.05) and recurrence free survival/progress free survival (RFS/PFS) (HR = 2.08, 95 % CI: 1.33–3.27, P < 0.05). Subgroup analysis showed that residence region (China and Japan), sample size, cancer type (solid or leukemia), follow-up months and analysis method (qPCR) did not alter the predictive value of miR-9 on OS in various cancers. Furthermore, no significant associations were detected for miR-9 expression and lymph node metastasis or distant metastasis. The present results suggest that promoted miR-9 expression is associated with poor OS in patients with general cancers.

Predictive value of miR-210 as a novel biomarker for pre-eclampsia: a systematic review protocol

IntroductionPre-eclampsia (PE) is a serious condition affecting 3–5% of all pregnancies worldwide. However, underlying molecular pathogenesis of this disease has largely remained unknown. Recently, several studies have indicated the possibility...

Evaluation of miR-182/miR-100 Ratio for Diagnosis and Survival Prediction in Bladder Cancer.

Abnormal expression of microRNAs (miRNAs) plays an important role in development of several cancer types, including bladder cancer (BCa). However, the relationship between the ratio of miR-181/miR-100 and the prognosis of BCa has not been studied yet. The aim of this study was to evaluate the expression of miR-182, miR-100 and their clinical significance in BCa. Upregulation of miR-182 and down-regulation of miR-100 were validated in tissue specimens of 134 BCa cases compared with 148 normal bladder epithelia (NBE) specimens using TaqMan-based real-time reverse transcription quantitative PCR (RT-qPCR). The diagnostic and prognostic evaluation of miR-182, miR-100, and miR-182/miR-100 ratio was also performed. miR-182 was upregulated in BCa and miR-100 was down-regulated in BCa compared with NBE (P < 0.001). The areas under receiver operating characteristic curves (AUCs-ROC) for miR-182 and miR-100 were 0.913 and 0.810, respectively. However, miR-182/miR-100 ratio increased the diagnostic performance, yielding an AUC of 0.981 (97.01% sensitivity and 90.54% specificity). Moreover, miR-182/miR-100 ratio was associated with pT-stage, histological grade, BCa recurrence and carcinoma in situ (P < 0.05 for all). Multivariate Cox regression analysis indicated that miR-182/miR-100 ratio was an independent prognostic factor for overall survival (Hazard ratio: 7.142; 95% CI: 2.106 - 9.891; P < 0.01). Furthermore, Kaplan-Meier curve analysis revealed that high-level of miR-182/miR-100 ratio was significantly correlated with shortened survival time for BCa patients (P < 0.01). The miR-182/miR-100 ratio may serve as a novel promising biomarker for diagnosis and survival prediction in BCa. Further studies are needed to elucidate the role of miR-182/miR-100 ratio as a non‑invasive diagnostic tool for BCa.

Abstract 214: TLR3 Mediates Neonatal Heart Repair and Regeneration Through Glycolysis-dependent YAP/TAZ Mediated miR-152 Expression

The neonatal heart possesses the capability of regenerating and repairing damaged myocardium which is lost when cardiac metabolism switches from predominate glycolysis to oxidative phosphorylation seven days after birth. We have observed that Toll-like receptor 3 (TLR3) deficient neonatal hearts exhibit impaired cardiac function and larger infarct size after myocardial infarction (MI). We also found that stimulation of neonatal cardiomyocytes with the TLR3 ligand, poly (I:C) significantly enhances glycolytic capacity. Our observation suggests that TLR3 is required for neonatal heart repair and regeneration of damaged myocardium. This study investigated the mechanisms by which TLR3 mediates neonatal heart regeneration and repair. Neonatal cardiomyocytes were isolated from one day old WT mice and treated with poly (I:C) (1μg/ml) for 12-36 hours. We observed that poly (I:C) treatment: i) significantly enhances glycolytic metabolism; ii) increases YAP/TAZ activation: iii) increases miR-152 expression; iv) suppresses expression of DNMT1 and p27kip1, and v) promotes cardiomyocyte proliferation. However, inhibition of glycolysis with 2-Deoxyglucose (2-DG) prevented poly (I:C)-induced YAP/TAZ activation and miR-152 expression in neonatal cardiomyocytes. Similarly, inhibition of YAP/TAZ activation with Verteprofin (VP) abolished poly (I:C) induced miR-152 expression and neonatal cardiomyocyte proliferation. To investigate the role of miR-152 in neonatal cardiomyocyte proliferation, we transfected neonatal cardiomyocytes with miR-152 mimics and observed that increased miR-152 levels significantly promotes neonatal cardiomyocyte proliferation. We also observed that transfection of neonatal cardiomyocytes with miR-152 mimics markedly suppresses the expression of DNMT1 and p27kip1. Inhibition of DNMT1 with 5Azcytidine significantly promotes neonatal cardiomyocyte proliferation. Finally, we observed that treatment of neonatal mice (n=6) with 2-DG abolished cardiac functional recovery 3 weeks after MI. We conclude that TLR3 is required for neonatal heart regeneration and repair after MI. The mechanisms involve glycolytic dependent activation of YAP/TAZ mediated by miR-152 which represses DNMT1/p27kip1 expression.

Abstract 272: miRNA-7 Leads to Enhanced Fibrosis in the Heart

MicroRNA-7 (miR-7) is known to target epidermal growth factor receptors (EGFRs) in oncogenic cells however, less is known about its role and function in the heart. Our studies have identified reciprocal expression pattern for ERBB2 (a member of EGFR family) in the context of miR-7 expression in human heart failure and in mice post-TAC (Transverse Aortic Constriction). To directly determine the role of miR-7 in the heart, we generated transgenic (Tg) mice with cardiomyocyte-specific overexpression of miR-7 (miR-7 Tg). miR-7 Tg mice are characterized by marked loss in ERBB2 expression compared to their wildtype littermate controls. Also, miR-7 Tg mice have age-dependent deterioration in cardiac dysfunction and is associated with dilation as measured by echocardiography (3 months - 60% FS, 6 month -52% FS and 12 months - 24%FS) and yet, they survive over 18 months as assessed by Kaplan-Meier curves. To investigate whether pathological stress would accelerate the deterioration in cardiac function, miR-7 Tg mice were subjected to TAC for two weeks. In contrast to the wild type littermates that showed significant hypertrophic response, miR-7 Tg mice have accelerated cardiac dysfunction and dilation following two weeks of TAC. Histological analysis shows increased collagen deposition in miR-7 Tg mice which is further accelerated following after TAC compared to their sham controls. These observations suggest that ERBB2 expression in the cardiomyocytes may play a critical role in delaying the pro-fibrotic response post-TAC by supporting an adaptive hypertrophic response in response to stress. Our study will discuss the mechanisms of increased fibrosis observed in miR-7 Tg mice subjected to TAC.

Abstract 372: MicroRNA-9 Inhibits Hyperglycemia-induced Cardiac Pyroptosis by Targeting ELAVL1

Diabetic cardiomyopathy is a common complication in patients with diabetes and is associated with underlying chronic inflammation and cardiac cell death, subsequently leading to left ventricular dysfunction and heart failure. ELAV-like protein 1 (ELAVL1, mRNA stabilizing protein) and NLRP3 activation (inflammasome complex protein)-mediated IL-1beta synthesis play a critical role in the progression of heart failure. However, ELAVL1 regulation of pyroptosis (caspase-1-mediated programmed apoptosis) and associated IL-1beta release in cardiomyocytes, especially under diabetic condition, remains elusive. Human diabetic, non-diabetic heart tissues, human ventricular cardiomyocytes and rat cardiomyoblasts exposed to high glucose (HG) were used for our studies. Our data demonstrates that human ventricular cardiomyocytes exposed to high glucose condition showed significant increase in ELAVL1 and NLRP3 expression with a concomitant increase in caspase-1 and IL-1 beta expression. Furthermore, human cardiac tissue from diabetic patients showed increased ELAVL1, caspase-1 and NLRP3 expression as compared to non-diabetic hearts. Intriguingly, ELAVL1 knockdown abrogates TNF-α induced canonical pyroptosis via NLRP3, caspase-1 and IL-1beta suppression. Interestingly, miRNA-9 expression significantly reduces in high glucose treated cardiomyocytes and in human diabetic hearts. Bioinformatics analysis and target validation assays showed that miR-9 directly targets ELAVL1. Inhibition of miR-9 up regulates ELAVL1 expression and activates caspase-1. Alternatively, miR-9 mimics attenuate hyperglycemia-induced ELAVL1 and inhibit cardiomyocyte pyroptosis. To our knowledge, this is the first report to demonstrate the role of miR-9/ELAVL1 in hyperglycemia-induced cardiac pyroptosis. Taken together our study highlights the potential therapeutic implications in preventing cardiomyocyte cell loss in human diabetic failing heart.

Exosome-mediated delivery of miR-9 induces cancer-associated fibroblast-like properties in human breast fibroblasts.

It is established that the interaction between microenvironment and cancer cells has a critical role in tumor development, given the dependence of neoplastic cells on stromal support. However, how this communication promotes the activation of normal (NFs) into cancer-associated fibroblasts (CAFs) is still not well understood. Most microRNA (miRNA) studies focused on tumor cell, but there is increasing evidence of their involvement in reprogramming NFs into CAFs. Here we show that miR-9, upregulated in various breast cancer cell lines and identified as pro-metastatic miRNA, affects the properties of human breast fibroblasts, enhancing the switch to CAF phenotype, thus contributing to tumor growth. Expressed at higher levels in primary triple-negative breast CAFs versus NFs isolated from patients, miR-9 improves indeed migration and invasion capabilities when transfected in immortalized NFs; viceversa, these properties are strongly impaired in CAFs upon miR-9 inhibition. We also demonstrate that tumor-secreted miR-9 can be transferred via exosomes to recipient NFs and this uptake results in enhanced cell motility. Moreover, we observed that this miRNA is also secreted by fibroblasts and in turn able to alter tumor cell behavior, by modulating its direct target E-cadherin, and NFs themselves. Consistently with the biological effects observed, gene expression profiles of NFs upon transient transfection with miR-9 show the modulation of genes mainly involved in cell motility and extracellular matrix remodeling pathways. Finally, we were able to confirm the capability of NFs transiently transfected with miR-9 to promote in vivo tumor growth. Taken together, these data provide new insights into the role of miR-9 as an important player in the cross-talk between cancer cells and stroma.

MicroRNA-138 functions as a tumor suppressor in osteosarcoma by targeting differentiated embryonic chondrocyte gene 2.

BackgroundMicroRNA-138 (miR-138) has been proven to be a tumor suppressor gene in various types of tumors. However, the expression and the role of miR-138 in human osteosarcoma are still poorly understood. We investigated the function and the underlying mechanism of miR-138 in osteosarcoma.MethodsThe expression of miR-138 in human osteosarcoma tissues and cell lines was detected by real-time PCR analysis. The gain-of-function and loss-of-function experiments were performed on osteosarcoma cell lines to investigate the effects of miR-138 on osteosarcoma progression, and to determine whether differentiated embryonic chondrocyte gene 2 (DEC2) mediates these effects. Cell proliferation, apoptosis and invasion were assessed by MTT, flow cytometry and transwell-matrigel assays. Dual-luciferase reporter assay was used to identify whether DEC2 is a direct target of miR-138.ResultsMiR-138 was significantly downregulated in human osteosarcoma tissues and cell lines. Moreover, miR-138 expression was significantly lower in metastatic osteosarcoma tissues than that in non-metastatic tissues. The in vitro gain-of-function and loss-of-function experiments demonstrated that miR-138 inhibited cell proliferation and invasion, and promoted cell apoptosis of human osteosarcoma cells. DEC2 was verified as a direct target of miR-138, and DEC2 could reverse the inhibitory effect of miR-138 on osteosarcoma progression.ConclusionsThese findings suggested that miR-138 acts as a tumor suppressor in osteosarcoma.miR-138 inhibited cell proliferation and invasion, as well as promoted cell apoptosis of human osteosarcoma cells, at least partially, by inhibiting the expression of DEC2. MiR-138/DEC2 may be a novel therapeutic target in osteosarcoma.

MicroRNA-138 suppresses proliferation, invasion and glycolysis in malignant melanoma cells by targeting HIF-1α.

MicroRNAs (miRs) may induce mRNA degradation or inhibit protein translation by directly binding to the 3'-untranslational region of target mRNAs. It has been reported that miR-138 is downregulated in malignant melanoma (MM) cells. However, the role of miR-138 in MM cell proliferation, invasion and energy metabolism remains unknown. These were investigated using reverse transcription-quantitative polymerase chain reaction was used to evaluate the expression of miR-138 and the mRNA expression of hypoxia-inducible factor-1α (HIF-1α), as HIF-1α serves a crucial role in glycolysis, which is important for tumor growth. In addition, western blot analysis was used to detected the protein expression of HIF-1α, while MTT and Transwell assays evaluated cell proliferation and invasion, respectively. Furthermore, glucose consumption and lactic acid production were assessed. These tests were conducted using the normal human melanocyte cell line HM and the MM cell line WM451, which was transfected variously with scramble miR mimics, miR-138 mimics, miR-138 inhibitor, non-specific small interfering (si)RNA, HIF-1α siRNA, or co-transfected with miR-138 mimics and pc-DNA3.1(+)-HIF-1α plasmid. The results showed that miR-138 was significantly downregulated in MM WM451 cells compared to a normal melanocyte cell line HM. Overexpression of miR-138 significantly inhibited the proliferation and invasion of WM451 cells. These effects were similar to those induced by the siRNA-mediated knockdown of HIF-1α, a direct target of miR-138. Further investigation found that miR-138 negatively regulated the protein expression of HIF-1α in WM451 cells. Moreover, upregulation of miR-138 notably inhibited the glycolysis level, as demonstrated by reduced glucose consumption and lactic acid production, which could be reversed by the overexpression of HIF-1α. In summary, the present study demonstrated that miR-138 is able to inhibit proliferation, invasion and glycolysis in MM cells, potentially by directly targeting HIF-1α.

The role of miR-9 during neuron differentiation of mouse retinal stem cells

Retinal stem cells (RSCs) have been defined as neural cells with the potential to self-renew and to generate all the different cell types of the nervous system following differentiation, which are an ideal engraft in retinal regeneration. In this research, mouse RSCs were isolated from retina, induced differentiation into neuron cells in vitro after over-expression of miR-9. The results showed that the RSCs could induce differentiation into neuron cells under the special medium, but when the miR-9 was over-expressed, the differentiated efficiency of neuron cells from RSCs could be promoted. This reason was demonstrated that polypyrimidine tract-binding protein 1 (PTBP1) was a repressor for polypyrimidine tract-binding protein 2 (PTBP2), during neuronal differentiation, miR-9 reduced PTBP1 levels, leading to the accumulation of correctly spliced PTBP2 mRNA and a dramatic increase in PTBP2 protein. And then miR-9 promoted neuron cells from RSCs were successful colonized into injured spinal cord for participation in tissue-repair. In conclusion, our research showed that the miR-9 promoted the differentiation of neuronal cells from RSCs, and this mechanism was miR-9 reduced the expression of PTBP1, increased the expression of PTBP2.