MicroRNA-143 suppresses oral squamous cell carcinoma cell growth, invasion and glucose metabolism through targeting hexokinase 2

MicroRNA-143 promotes cardiac ischemia-mediated mitochondrial impairment by the inhibition of protein kinase Cepsilon

The cardioprotection of protein kinase Cepsilon (PKCε) against myocardial infarction (MI) mediated by its anti-apoptotic property and underlying mechanism of targeted regulation by microRNA (miRNA) are not established. MI-induced injury, PKCε expression, and targeted regulation of miRNA-143 (miR-143) to PKCε have been evaluated using animal MI and cellular hypoxic models conjugated with series of state-of-art molecular techniques. The results demonstrated that PKCε significantly downregulated along with increased infarcted area and apoptotic and necrotic damage in MI model, and the targeted relationship and potential binding profile were established between miR-143 and PKCε. Both in vivo and in vitro ischemic tests showed that miR-143 induced apoptosis and necrosis, which was reversed by antagomiR-143 or AMO-143. The upregulation of miR-143 by transfection of miR-143 in vitro also induced cell loss, and this effect of miR-143 was completely reversed by co-transfection of miR-143 with AMO-143. The identically deleterious action of miR-143 on mitochondrial membrane potential and ATP synthesis was also observed in both animal MI and cellular hypoxic models, as well as miR-143 overexpressed models and converted by either antagomiR or AMO. Importantly, overexpression of miR-143 downregulated PKCε in all tested models and this downregulation was reversed in the presence of antagomiR or AMO. The direct targeted regulation of miR-143 on PKCε was confirmed by luciferase reporter and miRNA-masking tests. In conclusion, MI-mediated upregulation of miR-143 inhibits PKCε expression and consequently interference with the cardioprotection of PKCε to mitochondrial, and leads to mitochondrial membrane potential dissipation and myocardial death eventually.

MiR-181d functions as a potential tumor suppressor in oral squamous cell carcinoma by targeting K-ras

Oral squamous cell carcinoma (OSCC) is one of the most frequent carcinomas all over the world, and the mechanism of its progression remains poorly understood. MicroRNAs have been found to play pivotal roles in many cancers including OSCC. However, the detailed roles of miRNAs in OSCC remain to be fully elucidated. In this study, we aimed to investigate the role of miR-181d in the progression of OSCC and to further elucidate its possible regulatory mechanism. Differentially expressed miRNAs between OSCC tissues and adjacent normal tissues were identified by microarray and validated using quantitative reverse transcription PCR (qRT-PCR). Moreover, the effects of miR-181d on the cell viability and apoptosis were investigated. In addition, a direct target of miR-181a, K-ras was assessed by the luciferase reporter assay and western blot. K-ras was overexpressed to evaluate its reverse effect on miR-181d mediated tumor suppression in OSCC. A panel of 54 differentially expressed miRNAs was identified by microRNA array. Among them, miR-181d was showed to be significantly downregulated. We also found that miR-181d lowly expressed in 20 pairs of OSCC tissues and four cell lines compared with that in adjacent normal tissues and human normal oral keratinocyte cells. In vitro assays showed that upregulation of miR-181d markedly decreased cell viability and increased OSCC cell apoptosis. Furthermore, we demonstrated that K-ras was a target of miR-181d and there was a negative correlation between miR-181d and K-ras expression in OSCC tissues. Importantly, overexpression of K-ras reversed the inhibitory effects of miR-181d mimics on OSCC cells. miR-181d functions as an OSCC suppressor by targeting K-ras oncogene. Thus, miR-181d may serve as a novel therapeutic target for treating OSCC.