Studies have shown that several miRNAs play important roles in regulating a variety of cellular processes in gliomas. In these reports, upregulation of miR-193b has been found to be associated with a poor prognosis for glioma, but its functional mechanism in glioma remains unclear. This study investigates the roles of miR-193b in glioma tumor growth. We first showed that the expression of miR-193b was elevated in both glioma samples and glioma cells. Furthermore, downregulation of miR-193b by inhibitors was statistically correlated with a decrease in cell growth and a restored G1 accumulation. Luciferase assay and Western blot analysis revealed that Smad3 is a direct target of miR-193b. To prove that miR-193b regulated cell growth through the transforming growth factor-β (TGF-β) pathway in glioma cells by regulating Smad3, we tested endogenous targets of the TGF-β pathway by measuring the accumulation of p21 mRNAs after downregulation of miR-193b. The results confirmed that induction of p21 was promoted by miR-193b inhibitors in glioma cells, although this induction disappeared when Smad3 was knocked down with siRNA. Moreover, downregulation of Smad3 mitigates the miR-193b suppression of glioma proliferation. In conclusion, these results suggest that miR-193b regulated cell growth in glioma through the TGF-β pathway by regulating Smad3. Thus, our study indicates that miR-193b promotes cell proliferation by targeting Smad3 in human glioma, which may serve as a potentially useful target for development of miRNA-based therapies in the future.
Excessive microglial cells activation in response to inflammatory stimuli leads to synaptic loss, dysfunction, and neuronal cell death. Activated microglia are involved in the pathogenesis of neurological conditions and frequently contribute to several complications. Accumulating evidence suggests that signaling through PAR-1 is involved in inflammation, however, its function has yet to be fully elucidated. Here, we have demonstrated that the suppression of PAR-1 leads to down-regulation of inflammatory factors including IL-1β, IL-6, TNF-α, NO, as well as the prevention of activation of NF-κB in BV2 cells. In addition, we found that a PAR-1 antagonist, SCH, prevented LPS-induced excessive microglial activation in a dose-dependent manner. As a result of SCH treatment, neuronal cell death via up-regulation of Akt-mediated pathways was reduced. Our results demonstrate that the beneficial effects of SCH are linked to its ability to block an inflammatory response. Further, we found that SCH inhibited the death of PC12 neurons from the cytotoxicity of activated BV2 cells via activation of the PI3K/Akt pathway. These neuro-protective effects appear to be related to inhibition of PAR-1, and represents a novel neuroprotective strategy that could has potential for use in therapeutic interventions of neuroinflammatory disease.
Increasing evidence has confirmed that long non-coding RNAs (lncRNAs) serve critical roles in the development of a large number of human malignancies, including glioma. Several previously published studies have reported that the lncRNA retinal non-coding RNA3 (RNCR3; also termed LINC00599) exerts important roles in certain human malignancies; however, the precise biological role and underlying molecular mechanisms of RNCR3 in the development of glioma are yet to be fully elucidated. In the present study, it was revealed that the expression of RNCR3 was increased in glioma tissues compared with in corresponding adjacent normal tissues. Furthermore, increased levels of RNCR3 expression were associated with tumor progression and poor survival rates of patients with glioma. In addition, the U87 and U251 cell lines were selected to investigate the biological function and potential mechanisms of RNCR3 in glioma, and it was observed that RNCR3 knockdown led to an impairment of the proliferative and invasive abilities of cells; furthermore, G 1 phase arrest was induced in glioma cells in vitro. Finally, the results of western blot analyses revealed that knockdown of RNCR3 led to a decrease in the expression levels of phosphorylated Akt and glycogen synthase kinase-3β (GSK-3β), without any clear effect on the expression levels of total Akt and GSK-3β. Collectively, these results suggested that RNCR3 is able to regulate cell proliferation, the cell cycle and cell invasion in glioma, potentially via the Akt/GSK-3β signaling pathway.
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