Curcumin rescues breast cells from epithelial­mesenchymal transition and invasion induced by anti­miR­34a.

Breast cancer is the most prevalent type of cancer among women worldwide and it is characterized by a high morbidity. Curcumin is a naturally occurring compound derived from the rhizome of Curcuma longa and is known to have antioxidant and anticarcinogenic properties. Emerging evidence has indicated that microRNAs (miRNAs or miRs) function as oncogenes or tumor suppressor genes to control invasion and migration. The aim of this study was to evaluate the effects of curcumin on genes implicated in epithelial­mesenchymal transition (EMT) and to examine the involvement of Rho­A in the migration and invasion of MCF­10F and MDA­MB­231 breast cell lines. Furthermore, to the best of our knowledge, this is the first study to examine the effects of curcumin on Rho­A and on genes involved in EMT, such as Axl, Slug and CD24 in order to determine whether the compound is able to prevent migration and invasion by targeting miRNAs as a regulator of such genes. Specifically, we focused on miR­34a which acts as a tumor suppressor gene in human breast cell lines. The present study demonstrated that the Axl, Slug and CD24 genes were implicated in EMT, and Rho­A was also involved in the migration and invasion of MCF­10F and MDA­MB­231 cell lines. Curcumin also acted upon the miRNA as a regulator of genes implicated in EMT and upon Rho­A as well, affecting the migration and invasion of the cells. This occurred independently of their estrogen receptor (ER), progesterone receptor (PgR) and human epidermal growth factor receptor 2 (HER2) receptors in the non­malignant MCF­10F and malignant MDA­MB­231 breast cell lines, which are both negative for such receptors.

MicroRNA-15a/16-1 Antagomir Ameliorates Ischemic Brain Injury in Experimental Stroke.

BACKGROUND AND PURPOSE: Dysregulation of the miR-15a/16-1 cluster in plasma has been reported in patients with stroke as a potential biomarker for diagnostic and prognostic use. However, the essential role and therapeutic potential of the miR-15a/16-1 cluster in ischemic stroke are poorly understood. This study is aimed at investigating the regulatory role of the miR-15a/16-1 cluster in ischemic brain injury and insight mechanisms. METHODS: Adult male miR-15a/16-1 knockout and wild-type mice, or adult male C57 BL/6J mice injected via tail vein with the miR-15a/16-1-specific inhibitor (antagomir, 30 pmol/g), were subjected to 1 hour of middle cerebral artery occlusion and 72 hours of reperfusion. The neurological scores, brain infarct volume, brain water content, and neurobehavioral tests were then evaluated and analyzed. To explore underlying signaling pathways associated with alteration of miR-15a/16-1 activity, major proinflammatory cytokines were measured by quantitative polymerase chain reaction or ELISA and antiapoptotic proteins were examined by Western blotting. RESULTS: Genetic deletion of the miR-15a/16-1 cluster or intravenous delivery of miR-15a/16-1 antagomir significantly reduced cerebral infarct size, decreased brain water content, and improved neurological outcomes in stroke mice. Inhibition of miR-15a/16-1 significantly decreased the expression of the proinflammatory cytokines interleukin-6, monocyte chemoattractant protein-1, vascular cell adhesion molecule 1, tumor necrosis factor alpha, and increased Bcl-2 and Bcl-w levels in the ischemic brain regions. CONCLUSIONS: Our data indicate that pharmacological inhibition of the miR-15a/16-1 cluster reduces ischemic brain injury via both upregulation of antiapoptotic proteins and suppression of proinflammatory molecules. These results suggest that the miR-15a/16-1 cluster is a novel therapeutic target for ischemic stroke.

Altered MicroRNA Expression Is Responsible for the Pro-Osteogenic Phenotype of Interstitial Cells in Calcified Human Aortic Valves.

BACKGROUND: The transition of aortic valve interstitial cells (AVICs) to myofibroblastic and osteoblast-like phenotypes plays a critical role in calcific aortic valve disease progression. Several microRNAs (miRs) are implicated in stem cell differentiation into osteoblast. We hypothesized that an epigenetic mechanism regulates valvular pro-osteogenic activity. This study examined miR profile in AVICs of calcified valves and identified miRs responsible for AVIC phenotypic transition. METHODS AND RESULTS: AVICs were isolated from normal and diseased valves. The miR microarray analysis revealed 14 upregulated and 12 downregulated miRs in diseased AVICs. Increased miR-486 and decreased miR-204 levels were associated with higher levels of myofibroblastic biomarker α-smooth muscle actin and osteoblastic biomarkers runt-related transcription factor 2 (Runx2) and osterix (Osx). Cotransfection of miR-486 antagomir and miR-204 mimic in diseased AVICs reduced their ability to express Runx2 and Osx. The miR-486 mimic upregulated α-smooth muscle actin expression in normal AVICs through the protein kinase B pathway and moderately elevated Runx2 and Osx levels. Knockdown of α-smooth muscle actin attenuated Runx2 and Osx expression induced by miR-486. The miR-486 mimic and miR-204 antagomir synergistically promoted Runx2 and Osx expression and calcium deposition in normal AVICs and normal aortic valve tissue. CONCLUSIONS: In AVICs of calcified valves, increased levels of miR-486 induce myofibroblastic transition to upregulate Runx2 and Osx expression and synergize with miR-204 deficiency to elevate cellular and valvular pro-osteogenic activity. These novel findings indicate that modulation of the epigenetic mechanism underlying valvular pro-osteogenic activity has therapeutic potential for prevention of calcific aortic valve disease progression.

Silencing miR-181a produces neuroprotection against hippocampus neuron cell apoptosis post-status epilepticus in a rat model and in children with temporal lobe epilepsy.

Epilepsy is one of the most frequent neurological disorders. Recently, the regulation of microRNAs was found to be associated with epilepsy, but the molecular mechanism by which microRNA influences epilepsy process remains to be unveiled and the development of microRNA-based therapy requires more intensive research. In this study, five microRNAs with potential relevance to epilepsy were initially chosen: miR-132, miR-146a, miR-181a, miR-34a, and miR-124. Twenty-five children who were patients with epilepsy were selected as subjects to obtain tissue samples for the study. The miRNA-181a, which represented the most increased fold-changes in clinical samples, were then selected for further function study in mouse model. The temporal lobe epilepsy (TLE) model, along with lithium-pilocarpine-induced status epilepticus (SE), was established in Sprague-Dawley rats. The antagomir of miR-181a was used to determine the role of miR-181a in cell apoptosis. Analyses were conducted to determine the expression levels of miR-181a, neuronal apoptosis in post-SE, and activated caspase-3. We found evidence of significant time dependent up-regulation of miR-181a amongst post-SE rats and TLE on 24 h (4.47 ± 0.35), 7 days (4.85 ± 0.53), and 2 weeks (5.66 ± 0.64). Experiments with the miR-181a antagomir showed that this particular miRNA led to the inhibition of the protein expression of caspase-3, and was up-regulated in the course of seizure-induced neuronal apoptosis. This study provided evidence that targeting miR-181a leads to a neuroprotective response and is linked to an increase in the activation of the caspase-3 protein. These findings suggest that miR-181a may serve as a promising therapeutic target for epilepsy.