miR-29b Inhibitor Research Articles

Incidence and risk factors of acute kidney injury after thoracic endovascular aortic repair for type B aortic dissection

It has been demonstrated that the Angiotensin II (Ang II) contents and its receptor density in the kidney of young spontaneously hypertensive rats (SHRs) were significantly higher than in age-matched Wistar-Kyoto rats (WKYs). Ang II has been proved to induce Epithelial-Mesenchymal Transition (EMT). The present study was aimed at testing the role of miRNA-29b (miR-29b) in Ang II-induced EMT. Differential expression of miR-29b in renal cortex between 15-weeks SHRs and age-matched WKYs was determined by real-time quantitative polymerase chain reaction (RT-qPCR). The effect of miR-29b on EMT-associated genes such as transforming growth factor (TGF-b), a-smooth muscle actin (aSMA), CollagenI (ColI) was examined after transfecting miR-29b mimics (24 h before treatment with 10M Ang II) and miR-29b inhibitor into cultured renal tubular epithelial cells line_NRK-52E cells. Analysis of these genes expression was confirmed by RT-qPCR, western blot and immunofluorescence staining. Downregulation of miR-29b in renal cortex of SHRs was demonstrated by RT-qPCR compared with that of WKYs. Transfection of miR-29b inhibitor significantly increased the expression of TGF-b, a-SMA and ColI, while transfection of miR-29b mimics inhibited Ang II-induced upregulation of these genes expression. Expression of miR-29b in renal cortex of SHRs was decreased. The miR-29b may play a crucial role in EMT. Downregulation of miR-29b may exert a similar effect on NRK-52E cells as those seen in treatment of Ang II, while upregulation of miR-29b may protect NRK-52E cells from EMT induced by Ang II.

MicroRNA-29b protected renal fibrosis

It has been demonstrated that the Angiotensin II (Ang II) contents and its receptor density in the kidney of young spontaneously hypertensive rats (SHRs) were significantly higher than in age-matched Wistar-Kyoto rats (WKYs). Ang II has been proved to induce Epithelial-Mesenchymal Transition (EMT). The present study was aimed at testing the role of miRNA-29b (miR-29b) in Ang II-induced EMT. Differential expression of miR-29b in renal cortex between 15-weeks SHRs and age-matched WKYs was determined by real-time quantitative polymerase chain reaction (RT-qPCR). The effect of miR-29b on EMT-associated genes such as transforming growth factor (TGF-b), a-smooth muscle actin (aSMA), CollagenI (ColI) was examined after transfecting miR-29b mimics (24 h before treatment with 10M Ang II) and miR-29b inhibitor into cultured renal tubular epithelial cells line_NRK-52E cells. Analysis of these genes expression was confirmed by RT-qPCR, western blot and immunofluorescence staining. Downregulation of miR-29b in renal cortex of SHRs was demonstrated by RT-qPCR compared with that of WKYs. Transfection of miR-29b inhibitor significantly increased the expression of TGF-b, a-SMA and ColI, while transfection of miR-29b mimics inhibited Ang II-induced upregulation of these genes expression. Expression of miR-29b in renal cortex of SHRs was decreased. The miR-29b may play a crucial role in EMT. Downregulation of miR-29b may exert a similar effect on NRK-52E cells as those seen in treatment of Ang II, while upregulation of miR-29b may protect NRK-52E cells from EMT induced by Ang II.

MicroRNA-10b promotes migration and invasion through KLF4 and HOXD10 in human bladder cancer

The present study was performed to investigate the effect of microRNA-10b (miR-10b) on cell migration and invasion in human bladder cancer (BC). Real-time PCR was performed to detect the expression of miR-10b in BC cell lines. miR-10b mimics, the negative control for mimics, miR-10b inhibitor and the negative control for inhibitor were transfected into BC cell lines and the effects of miR-10b on the migration and invasion of cells were investigated through Transwell assay. Meanwhile, protein levels of KLF4, HOXD10, E-cadherin and MMP14 were measured. Luciferase assays were also performed to validate KLF4 and HOXD10 as miR-10b targets. In vivo metastasis assay was performed to validate if miR-10b can promote BC cell line metastasis in vivo. miR-10b is significantly upregulated in BC cell lines and metastatic tissues. Increased miR-10b expression significantly enhanced BC cell migration and invasion, while decreased miR-10b expression reduced cell migration and invasion. In vivo metastasis assay demonstrated that overexpression of miR-10b markedly promoted BC metastasis. Moreover, KLF4 and HOXD10 were identified as direct targets of miR-10b in BC cells. Silencing of KLF4 or HOXD10 recapitulated the pro-metastatic function. Furthermore, we found that E-cadherin and MMP14 may be the downstream factors of KLF4 and HOXD10 in the suppression of BC metastasis by miR-10b. These data suggest that miR-10b may function as oncogenes in BC cells. Targeting these novel strategies, inhibition of miR-10b/KLF4/E-cadherin axis and miR-10b/HOXD10/MMP14 axis may be helpful as a therapeutic approach to block BC cell metastasis.

A lentivirus-mediated miR-23b sponge diminishes the malignant phenotype of glioma cells in vitro and in vivo

microRNA (miRNA) sponges are RNA molecules with repeated miRNA binding sequences that can sequester miRNAs from their endogenous target mRNAs, and a stably expressed miRNA sponge is particularly valuable for long-term loss-of-function studies in vitro and in vivo. Glioblastoma multiforme (GBM) is the most common primary brain tumor in adults and is characterized by extraordinarily angiogenic, invasive and migratory capabilities, hallmark features that make the disease incurable. Nonetheless, improvements in clinical treatment and a better understanding of the underlying molecular mechanisms have been achieved within the past few decades. miR-23b has previously been found to function as a tumor oncogene in GBM. In the present study, we employed an microRNA sponge that was forcibly expressed using a lentiviral vector to knock down the expression of miR-23b in vitro and in vivo and assessed the pleiotropic effects on glioma angiogenesis, invasion and migration. We demonstrated that the inhibition of miR-23b in glioma cell lines and orthotopic tumor mouse models resulted in a reduction in tumor malignancy, through the downregulation of HIF-1α, β-catenin, MMP2, MMP9, VEGF and ZEB1 and increased expression of VHL and E-cadherin. Therefore, we suggest that this miR-23b sponge could be developed into a promising anticancer therapy either alone or in combination with current targeted therapies.

A8.12 MIR-125B controls mitochondrial functions and dynamics in monocytes

Background and ObjectivesMonocytes play essential roles in immune defense but are also implicated in pathological inflammatory responses due to excessive and prolonged activation. How survival and apoptotic regulators control monocyte...

Critical role of miR-10b in transforming growth factor-β1-induced epithelial–mesenchymal transition in breast cancer

Epithelial-mesenchymal transition (EMT) is a key process in the tumor metastatic cascade that is characterized by the loss of cell-cell junctions and cell polarity, resulting in the acquisition of migratory and invasive properties. Recent evidence showed that altered microRNA-10b (miR-10b) expression was implicated in the occurrence of EMT of breast cancer. However, the exact role and underlying mechanisms of miR-10b in the EMT of breast cancer still remain unknown. In this study, miR-10b was found to be upregulated in breast cancer tissues and breast cancer cell lines and the expression of miR-10b was shown to be closely correlated with aggressiveness in breast cancer. Treating breast cancer cells with the miR-10b inhibitor increased E-cadherin expression while decreasing vimentin expression. At the same time, on inhibition of miR-10b, the invasion and proliferation ability of breast cancer cells also decreased. Transforming growth factor-β (TGF-β) is a multifunctional cytokine that induces EMT in multiple cell types. Here, we identified miR-10b as a target gene of TGF-β1. The expression of miR-10b increased during TGF-β1-induced EMT of breast cancer cells. Further study showed that inhibition of miR-10b expression partially reversed the EMT, invasion and proliferation induced by TGF-β1 in breast cancer cells. Taken together, these results demonstrated a novel function for miR-10b in TGF-β1-induced EMT in breast cancer and increased their metastatic potential. MiR-10b might become a possible target for gene therapy in breast cancer.

Spatial correlation between patterns of wall permeability and patterns of multidirectional disturbed blood flow in rabbit aorta

Spatial correlation between patterns of wall permeability and patterns of multidirectional disturbed blood flow in rabbit aorta

The role of microRNA-133b and its target gene FSCN1 in gastric cancer

Increasing evidences have documented that microRNAs (miRNAs) act as oncogenes or tumor suppressors in gastric cancer (GC). In this study, we aimed to investigate the expression of miR-133b in a large number of GC samples and elucidate its role in GC carcinogenesis and the detailed mechanism. We used Taqman probe stem-loop real-time PCR to accurately measure the levels of miR-133b in 100 pairs of gastric cancer tissues and the adjacent non-neoplastic tissues. miR-133b mimics were overexpressed in GC cell lines, miR-133b inhibitors were also introduced in GES cells to investigate its role on regulating cell proliferation, cell migration and cell invasion. The target of miR-133b was identified by luciferase reporter assay and western blot. Fascin actin-bundling protein 1 (FSCN1) siRNA was used to achieve the knockdown of FSCN1 in GC cells and to investigate its role on modulating GC cell proliferation and invasion. miR-133b was significantly down-regulated in GC cell lines and in GC tissues compared with adjacent normal tissues. Moreover, lower-level of miR-133b was also associated with venous invasion and a more aggressive tumor phenotype. Re-introduction of miR-133b in GC cells can inhibit cell proliferation, cell migration and invasion. In contrary, knockdown of miR-133b in GES cells can promote cell proliferation and invasion. Further investigation indicated that miR-133b targeted FSCN1 in GC cells and knockdown of FSCN1 can also inhibit GC cell growth and invasion. Our findings demonstrated that miR-133b was significantly down-regulated in GC tissues and exerted its tumor suppressor role in GC cells. The investigation of the detailed mechanism showed that miR-133b directly targeted FSCN1 which functioned as an oncogenic gene in GC cells. These results suggested that miR-133b can be developed as a new diagnostic marker or therapeutic target for GC.

Id-1, a Protein Repressed by miR-29b, Facilitates the TGFβ1-Induced Epithelial-Mesenchymal Transition in Human Ovarian Cancer Cells

Background: Transforming growth factor beta 1 (TGFβ1) can induce epithelial-mesenchymal transition (EMT) in various human cancers, but the complex mechanisms underlying this have not been fully elucidated. Inhibitor of DNA binding 1 (Id-1) has been identified as a novel marker of ovarian cancer progression. This study aims to investigate the role of Id-1 in TGFβ1-induced EMT in human ovarian cancer cells. Methods: Ovarian cancer cells expressing or not expressing Id-1 were incubated with TGFβ1. Changes in the EMT markers E-cadherin, vimentin, N-cadherin, Id-1, and miR-29b were detected using western blotting and qPCR analyses. Wound healing, transwell migration, and invasion assays were performed in cells where Id-1 was either knocked down or overexpressed. The effects of transfecting miR-29b mimics and inhibitors on Id-1 mRNA and protein expression were assessed. The interaction between miR-29b and Id-1 was confirmed using a luciferase reporter assay. Results: Id-1 expression was increased and miR-29b expression was repressed in TGFβ1-responsive ovarian cancer cells. Id-1 overexpression increases and Id-1 knockdown decreases cell migration and invasion capacities. Id-1 silencing leads to a partial blocking of TGFβ1-induced EMT. miR-29b negatively regulates Id-1 expression. Direct binding of miR-29b to the 3'UTR region of Id-1 was confirmed using a luciferase reporter assay. Conclusion: Id-1, a protein repressed by miR-29b, facilitates TGFβ1-induced EMT in human ovarian cancer cells and represents a promising therapeutic target for treating ovarian cancer.

Curcumin up-regulates phosphatase and tensin homologue deleted on chromosome 10 through microRNA-mediated control of DNA methylation--a novel mechanism suppressing liver fibrosis.

Phosphatase and tensin homologue deleted on chromosome 10 (PTEN) has been reported to play a role in the suppression of activated hepatic stellate cells (HSCs). Moreover, it has been demonstrated that hypermethylation of the PTEN promoter is responsible for the loss of PTEN expression during HSC activation. Methylation is now established as a fundamental regulator of gene transcription. MicroRNAs (miRNAs), which can control gene expression by binding to their target genes for degradation and/or translational repression, were found to be involved in liver fibrosis. However, the mechanism responsible for miRNA-mediated epigenetic regulation in liver fibrosis still remained unclear. In the present study, curcumin treatment significantly resulted in the inhibition of cell proliferation and an increase in the apoptosis rate through the up-regulation of PTEN associated with a decreased DNA methylation level. Only DNA methyltransferase 3b (DNMT3b) was reduced invivo and invitro after curcumin treatment. Further studies were performed aiming to confirm that the knockdown of DNMT3b enhanced the loss of PTEN methylation by curcumin. In addition, miR-29b was involved in the hypomethylation of PTEN by curcumin. MiR-29b not only was increased by curcumin in activated HSCs, but also was confirmed to target DNMT3b by luciferase activity assays. Curcumin-mediated PTEN up-regulation, DNMT3b down-regulation and PTEN hypomethylation were all attenuated by miR-29b inhibitor. Collectively, it is demonstrated that curcumin can up-regulate miR-29b expression, resulting in DNMT3b down-regulation in HSCs and epigenetically-regulated PTEN involved in the suppression of activated HSCs. These results indicate that miRNA-mediated epigenetic regulation may be a novel mechanism suppressing liver fibrosis.

MicroRNA miR-27b Rescues Bone Marrow–Derived Angiogenic Cell Function and Accelerates Wound Healing in Type 2 Diabetes Mellitus

Vascular precursor cells with angiogenic potentials are important for tissue repair, which is impaired in diabetes mellitus. MicroRNAs are recently discovered key regulators of gene expression, but their role in vascular precursor cell-mediated angiogenesis in diabetes mellitus is unknown. We tested the hypothesis that the microRNA miR-27b rescues impaired bone marrow-derived angiogenic cell (BMAC) function in vitro and in vivo in type 2 diabetic mice. BMACs from adult male type 2 diabetic db/db and from normal littermate db/+ mice were used. miR-27b expression was decreased in db/db BMACs. miR-27b mimic improved db/db BMAC function, including proliferation, adhesion, tube formation, and delayed apoptosis, but it did not affect migration. Elevated thrombospondin-1 (TSP-1) protein in db/db BMACs was suppressed on miR-27b mimic transfection. Inhibition of miR-27b in db/+ BMACs reduced angiogenesis, which was reversed by TSP-1 small interfering RNA (siRNA). miR-27b suppressed the pro-oxidant protein p66(shc) and mitochondrial oxidative stress, contributing to its protection of BMAC function. miR-27b also suppressed semaphorin 6A to improve BMAC function in diabetes mellitus. Luciferase binding assay suggested that miR-27b directly targeted TSP-1, TSP-2, p66(shc), and semaphorin 6A. miR-27b improved topical cell therapy of diabetic BMACs on diabetic skin wound closure, with a concomitant augmentation of wound perfusion and capillary formation. Normal BMAC therapy with miR-27b inhibition demonstrated reduced efficacy in wound closure, perfusion, and capillary formation. Local miR-27b delivery partly improved wound healing in diabetic mice. miR-27b rescues impaired BMAC angiogenesis via TSP-1 suppression, semaphorin 6A expression, and p66shc-dependent mitochondrial oxidative stress and improves BMAC therapy in wound healing in type 2 diabetic mice.

Role of microRNA181-b and its target gene oncogene deleted in liver cancer-1 in hepatocellular carcinoma pathogenesis

Objective To investigate the regulatory effect ofmicroRNA-181b (miR-181b) on deleted in liver cancer-1 (DLC-1) and its role in hepatocarcinogenesis.Methods miR-181b and DLC-1 mRNA expression levels in normal tissue,paraneoplastic tissue,liver cancer tissue and liver cancer cells were detected by using real-time fluorescent quantitative polymerase chain reaction (FQ-PCR).DLC-1 protein expression was detected by using Western blotting.miR-181b inhibitor was transfected into SMMC7721 cells and the expression changes of DLC-1 mRNA and protein were examined by using FQ-PCR and Western blotting respectively.Results miR-181b was up-regulated in hepatocellular carcinoma and adjacent tissues as compared to normal liver tissues and the expression of miR-181 b was also increased in SMMC7721 cells as compared to fetal liver cells LO2,whereas the expression levels of DLC-1 mRNA and protein were decreased in paraneoplastic and HCC tissues compared with normal liver tissues.The expression of miR-181b and DLC-1 was negatively correlated.No obvious difference was found in the DLC-1 mRNA expression after miR-181b inhibitor transfection.Conclusion The DLC-1 abnormal low-expression may play a dynamic role in hepatocarcinogenesis due to the miR-181 b up-regulation. Key words: Carcinoma, hepatocellular; MicroRNA-181b; Deleted in liver cancer-1

MiR-200b suppresses invasiveness and modulates the cytoskeletal and adhesive machinery in esophageal squamous cell carcinoma cells via targeting Kindlin-2

To further our understanding of the pathobiology of esophageal squamous cell carcinoma (ESCC), we previously performed microRNA profiling that revealed downregulation of miR-200b in ESCC. Using quantitative real-time PCR applied to 88 patient samples, we confirmed that ESCC tumors expressed significantly lower levels of miR-200b compared with the respective adjacent benign tissues (P = 0.003). Importantly, downregulation of miR-200b significantly correlated with shortened survival (P = 0.025), lymph node metastasis (P = 0.002) and advanced clinical stage (P = 0.020) in ESCC patients. Quantitative mass spectrometry identified 57 putative miR-200b targets, including Kindlin-2, previously implicated in the regulation of tumor invasiveness and actin cytoskeleton in other cell types. Enforced expression of miR-200b mimic in ESCC cells led to a decrease of Kindlin-2 expression, whereas transfection of miR-200b inhibitor induced Kindlin-2 expression. Furthermore, transfection of miR-200b mimic or knockdown of Kindlin-2 in ESCC cells decreased cell protrusion and focal adhesion (FA) formation, reduced cell spreading and invasiveness/migration. Enforced expression of Kindlin-2 largely abrogated the inhibitory effects of miR-200b on ESCC cell invasiveness. Mechanistic studies revealed that Rho-family guanosine triphosphatases and FA kinase mediated the biological effects of the miR-200b-Kindlin-2 axis in ESCC cells. To conclude, loss of miR-200b, a frequent biochemical defect in ESCC, correlates with aggressive clinical features. The tumor suppressor effects of miR-200b may be due to its suppression of Kindlin-2, a novel target of miR-200b that modulates actin cytoskeleton, FA formation and the migratory/invasiveness properties of ESCC.

GW24-e0815 The role of microRNA-29b in renal fibrosis induced by angiotensin II

ObjectivesPrimary study have demonstrated that the Angiotensin II (Ang II) contents and the its receptor density in the kidney of young spontaneously hypertensive rats (SHR) were significantly higher than age-matched...

MiR-125b Inhibitor May Enhance the Invasion-Prevention Activity of Temozolomide in Glioblastoma Stem Cells by Targeting PIAS3

Temozolomide, an alkylating agent, is a promising chemotherapeutic agent for treating glioblastoma. Although chemotherapy with temozolomide may restrain tumor growth for some months, invariable tumor recurrence suggests that cancer stem cells maintaining these tumors persist. Previous research has shown that temozolomide can inhibit the proliferation of human glioblastoma stem cells (GSCs); however, no research has focused on the invasion of GSCs, which is an important factor for glioblastoma recurrence. Accumulating evidence indicates that microRNA (miR)-125b over-expression in GSCs may increase their invasiveness. Our objective was to identify the effects and mechanism of action of an miR-125b inhibitor combined with temozolomide in the invasive pathogenesis of GSCs. We modified the levels of miR-125b expression in primary GSCs in order to observe the effect on sensitivity to temozolomide on invasion, and we further analyzed the differences in mechanism between miR-125b treatment alone and treatment with miR-125b plus temozolomide using the Cancer PathwayFinder PCR Array. Our results demonstrated that either an miR-125b inhibitor or temozolomide could modestly inhibit the invasiveness of GSCs. Furthermore, GSCs that were pre-transfected with an miR-125b inhibitor, then treated with temozolomide, showed significantly decreased invasiveness when compared with GSCs treated with an miR-125b inhibitor or temozolomide alone. Further research into the underlying mechanism demonstrated that the miR-125b inhibitor enhanced the invasion-prevention activity of temozolomide in GSCs through targeting PIAS3 (protein inhibitor of activated STAT [signal transducer and activator of transcription]), which contributed to reduced STAT3 transcriptional activity and subsequent decreased expression of matrix metalloproteinase (MMP)-2 and -9. miR-125b could play a role in the development of temozolomide resistance in GSCs. Inhibition of miR-125b expression may enhance sensitivity of GSCs to temozolomide by targeting PIAS3 on cell invasion.

MicroRNA-125b inhibitor sensitizes human primary glioblastoma cells to chemotherapeutic drug temozolomide on invasion

Malignant gliomas are treated with a combination of surgery, radiation, and temozolomide (TMZ), but these therapies ultimately fail due to tumor recurrence. In this study, we aimed to identify the combined effects of miR-125b and TMZ involved in the invasive pathogenesis of glioblastoma cells. The effects of miR-125b and TMZ on cell invasion were analyzed by Transwell assays. Unexpectedly, either overexpression or downregulation of miR-125b has no function on glioblastoma cell invasion. However, knockdown of miR-125b could enhance the effects of TMZ on glioblastoma cell invasion. Conversely, overexpression of miR-125b could decrease such effects of TMZ. Further research on the mechanism demonstrated that such function of miR-125b knockdown on enhancing the effects of TMZ was involved in downregulation of Notch1. Notch1 was overexpressed in glioblastoma cells, and found by us that downregulation of Notch1 expression decreased the cell invasion of glioblastoma cells. Knockdown of miR-125b combined with TMZ enhancely downregulated Notch1 and inhibited cell invasion of malignant glioblastoma. These findings indicate that the combination of miR-125b inhibitor and TMZ treatment could effectively inhibit the glioblastoma cell invasion by inhibiting Notch1 expression.

MTA1 promotes the invasion and migration of non-small cell lung cancer cells by downregulating miR-125b

BackgroundThe metastasis-associated gene 1 (MTA1) has been identified as one critical regulator of tumor metastasis. Previously, we identified miR-125b as a downregualted miRNA in non-small cell lung cancer (NSCLC) cell line upon MTA1 depletion. However, the role of miR-125b and MTA1 in the regulation of NSCLC metastasis remains unclear.MethodsStable MTA1 knockdown NSCLC cell lines 95D and SPC-A-1 were established by transfection with MTA1 shRNA. The effects of MTA1 depletion on the expression of miR-125b and cell migration and invasion were examined by real-time PCR, wound healing and matrigel invasion assay.ResultsMTA1 knockdown led to the upregulation of miR-125b level in NSCLC cells. Furthermore, MTA1 knockdown reduced while miR-125b inhibitor enhanced cell migration and invasion of NSCLC cells. Notably, miR-125b inhibitor antagonized MTA1 siRNA induced inhibition of cell migration and invasion.ConclusionMTA1 and miR-125b have antagonistic effects on the migration and invasion of NSCLC cells. The newly identified MTA1-miR-125b axis will help further elucidate the molecular mechanism of NSCLC progression and suggest that ectopic expression of miR-125b is a potentially new therapeutic regimen against NSCLC metastasis.

Abstract 539: MicroRNA-27b Regulates Salt-Inducible Kinase 1 (SIK1) in Vascular Fibrosis

Arterial fibrosis is one of the main underlying causes of vascular stiffness and various associated diseases, such as hypertension, congestive heart failure, aortic aneurysm development and renal failure. Consequently there is a growing interest in (patho)-mechanisms governing the underlying process of arterial fibrosis and successive vascular stiffness. Recently, a novel class of small noncoding RNAs, termed microRNAs (miRs), have emerged as powerful cellular regulators in disease processes. Furthermore, they have become an intriguing target for therapeutic intervention. Aim of the present study was to explore whether miRs are regulating the expression of salt-inducible kinase 1 (SIK1), which we previously identified as a crucial regulator of fibrosis in heart-/kidney- failure and arterial hypertension. Using different bioinformatic target prediction algorithms, we identified several miRs with predicted conserved sites on the Sik1 gene, including miRs-27a/b, -130a, -148a/b and -152. By analyzing aorta, heart and kidney specimen from Sik-/- and Sik+/+ mice, we were able to detect that miR-27b was the only miR being significantly altered in all three tissues. We proceeded by treating human aortic smooth muscle cells as well as adventitial fibroblasts with TGF-β, to induce a pro-fibrotic response. Interestingly, treatment with TGF-β substantially increased miR-27b expression as well as other components of the extracellular matrix, such as collagen (Col1a1) and fibronectin (Fn1) through repression of SIK1. Overexpression of miR-27b, utilizing a pre-miR precursor, substantially decreased SIK-1 expression and further augmented the pro-fibrotic response, as indicated by raising collagen and Fn1 expressions. The present study explores the regulatory role of miR-27b in different vascular fibrosis associated pathologies. We were able to show that miR-27b, a novel downstream-target of TGF-β signalling pathways, suppresses the expression of SIK1, which itself has been identified as a key regulator of arterial hypertension and consequential heart and kidney failure. On-going studies, utilizing inhibition of miR-27b can become an interesting novel therapeutic strategy to regulate SIK1 levels in vascular fibrosis and arterial stiffness.

MiR-23b regulates cytoskeletal remodeling, motility and metastasis by directly targeting multiple transcripts.

Uncontrolled cell proliferation and cytoskeletal remodeling are responsible for tumor development and ultimately metastasis. A number of studies have implicated microRNAs in the regulation of cancer cell invasion and migration. Here, we show that miR-23b regulates focal adhesion, cell spreading, cell-cell junctions and the formation of lamellipodia in breast cancer (BC), implicating a central role for it in cytoskeletal dynamics. Inhibition of miR-23b, using a specific sponge construct, leads to an increase of cell migration and metastatic spread in vivo, indicating it as a metastatic suppressor microRNA. Clinically, low miR-23b expression correlates with the development of metastases in BC patients. Mechanistically, miR-23b is able to directly inhibit a number of genes implicated in cytoskeletal remodeling in BC cells. Through intracellular signal transduction, growth factors activate the transcription factor AP-1, and we show that this in turn reduces miR-23b levels by direct binding to its promoter, releasing the pro-invasive genes from translational inhibition. In aggregate, miR-23b expression invokes a sophisticated interaction network that co-ordinates a wide range of cellular responses required to alter the cytoskeleton during cancer cell motility.

Expression and significance of microRNA-181b in hepatocellular carcinoma

Objective To explore the role of microRNA-181b （miR-181b） in the pathogenesis of human hepatocellular carcinoma （HCC）. Methods We detected the expressions of miR-181 b by using re- al-time quantitative polymerase chain reaction （Real-time PCR） in LO2 （normal human liver cell line）, HepG2 and SMMC7721 （human HCC cell lines） , normal liver tissues, para-cancerous tissue and cancer- ous tissues surgically resected from 35 cases of HCC. Cell Counting Kit-8 （ CCK-8 ） assay and growth curve were used to asses the effect of miR-181b inhibitor on proliferation of HCC cells. Results The expression of miR-181b in HepG2 and SMMC7721 cells was significantly higher than in L02 cells （0. 582 ± 0. 032 and 0. 716 ±0. 045 vs. 0. 255 ±0. 039,P 〈0. 05）, and that in cancerous tissue was significantly higher than in normal liver tissues and para-cancerous tissues （0. 636 ± 0. 038 vs. 0. 156 ± 0. 005 and 0. 167 ± 0. 023, P 〈0. 05）. miR-181b inhibitor could reduce the proliferative ability of HCC cells. Conclusion These re- suits indicate that the high expression of miR-181b is probably involved in HCC pathogenesis. Downregula- tion of miR-181b expression can inhibit the proliferation of HCC cells, miR-181b may act as a molecular tar- get for HCC diagnosis and targeted therapy. Key words: MicroRNA-181 b ; Carcinoma, hepatocellular; Real-time quantitative polymerase chain reaction