Dongwei Dai

Decreased miR-106a inhibits glioma cell glucose uptake and proliferation by targeting SLC2A3 in GBM

BackgroundMiR-106a is frequently down-regulated in various types of human cancer. However the underlying mechanism of miR-106a involved in glioma remains elusive.MethodsThe association of miR-106a with glioma grade and patient survival was analyzed. The biological function and target of miR-106a were determined by bioinformatic analysis and cell experiments (Western blot, luciferase reporter, cell cycle, ntracellular ATP production and glucose uptake assay). Finally, rescue expression of its target SLC2A3 was used to test the role of SLC2A3 in miR-106a-mediated cell glycolysis and proliferation.ResultsHere we showed that miR-106a was a tumor suppressor miRNA was involved in GBM cell glucose uptake and proliferation. Decreased miR-106a in GBM tissues and conferred a poor survival of GBM patients. SLC2A3 was identified as a core target of miR-106a in GBM cells. Inhibition of SLC2A3 by miR-106a attenuated cell proliferation and inhibited glucose uptake. In addition, for each biological process we identified ontology-associated transcripts that significantly correlated with SLC2A3 expression. Finally, the expression of SLC2A3 largely abrogated miR-106a-mediated cell proliferation and glucose uptake in GBM cells.ConclusionsTaken together, miR-106a and SLC2A3 could be potential therapeutic approaches for GBM.

miR-22 inhibits the proliferation, motility, and invasion of human glioblastoma cells by directly targeting SIRT1

Recently, microRNAs (miRNAs), a kind of small and non-coding RNA, can target the downstream molecules. Increasing evidence demonstrates that miRNAs meditate the onset and progression of a variety of tumors. In the present study, we carried out gene transfection, western blot, and reverse transcription PCR (RT-PCR) to explore the role of miR-22 in glioblastoma tissues and cell lines. Here, we verified that the expression of miR-22 was downregulated in glioblastoma tissues and cells rather than matched non-tumor tissues and normal human astrocyte (NHA) cells (p < 0.001). By contrast, SIRT1 messenger RNA (mRNA) and protein were upregulated in glioblastoma tissues and cells (p < 0.001). In vitro miR-22 mimics interfered with cell proliferation, migration, and invasion of U87 and U251 cells. Mechanically, the 3′-untranslated regions (3′-UTRs) of SIRT1 were a direct target of miR-22, leading to the decreased expression of SIRT1 protein in U87 and U251 cells. Meanwhile, miR-22 mimics also inhibited the expression of epidermal growth factor receptor (EGFR) and matrix metallopeptidase 9 (MMP9). In conclusion, miR-22 inhibited cell proliferation, migration, and invasion via targeting the 3′-UTR of SIRT1 in the progression of glioblastoma and miR-22-SIRT1 pathway can be recommended as a potential target for treatment of glioblastoma.

miR‐372 Regulates Glioma Cell Proliferation and Invasion by Directly Targeting PHLPP2

MicroRNAs are known to be involved in carcinogenesis and tumor progression in glioma. Recently, microRNA‐372 (miR‐372) has been proved to play a substantial role in several human cancers, but its functions in glioma remain unclear. In this study, we confirmed that miR‐372 was commonly upregulated in glioma cell lines and tissues. Downregulation of miR‐372 markedly inhibited cell proliferation and invasion and induced G1/S arrest and apoptosis. Consistently, the xenograft mouse model also unveiled the suppressive effects of miR‐372 knockdown on tumor growth. Further studies revealed that miR‐372 modulated the expression of PHLPP2 by directly targeting its 3′‐untranslated region (3′‐UTR) and that miR‐372 expression was inversely correlated with PHLPP2 expression in glioma samples. Silencing of PHLPP2 could rescue the inhibitory effect of miR‐372 inhibitor. Moreover, miR‐372 knockdown suppressed the phosphorylation levels of the major components of PI3K/Akt pathway including Akt, mTOR, and P70S6K. Taken together, our results suggest that miR‐372 functions as an oncogenic miRNA through targeting PHLPP2 in glioma. J. Cell. Biochem. 116: 225–232, 2015.

Serum miRNA Signature in Moyamoya Disease

Moyamoya disease (MMD) is a cerebrovascular disease characterized by progressive stenosis of the intracranial internal carotid arteries and their proximal branches. However, the etiology of this rare disease remains unknown. Serum microRNA (miRNA) profiles have been screened to identify novel biomarkers of prognostic values. Here, we identified serum miRNAs that might play an important role in the pathogenesis of MMD. A genome-wide miRNA array analysis of two pooled serum samples from patients with MMD and controls revealed 94 differentially expressed serum miRNAs, including 50 upregulated and 44 downregulated miRNAs. In an independent MMD cohort, real-time PCR confirmed that miR-106b, miR-130a and miR-126 were significantly upregulated while miR-125a-3p was significantly downregulated in serum. GO analysis showed that the differentially expressed serum miRNAs were enriched in metabolic processes, transcription and signal transduction. Pathway analysis showed that the most enriched pathway was mTOR signaling pathway with 16 potential, functional targets. Finally, we found that 16 and 13 aberrant serum miRNAs coordinately inhibited RNF213 and BRCC3 protein expression at the posttranscriptional level, respectively, resulting in defective angiogenesis and MMD pathogenesis. To our knowledge, this is the first study to identify a serum miRNA signature in MMD. Modulation of the mechanism underlying the role of serum miRNAs in MMD is a potential therapeutic strategy and warrants further investigations.

The histone deacetylase SIRT6 suppresses the expression of the RNA-binding protein PCBP2 in glioma

More than 80% of tumors that occur in the brain are malignant gliomas. The prognosis of glioma patients is still poor, which makes glioma an urgent subject of cancer research. Previous evidence and our present data show that PCBP2 is over-expressed in human glioma tissues and predicts poor outcome. However, the mechanism by which PCBP2 is regulated in glioma remains elusive. We find that SIRT6, one of the NAD(+)-dependent class III deacetylase SIRTUINs, is down-regulated in human glioma tissues and that the level of SIRT6 is negatively correlated with PCBP2 level while H3K9ac enrichment on the promoter of PCBP2 is positively correlated with PCBP2 expression. Furthermore, we identify PCBP2 as a target of SIRT6. We demonstrate that PCBP2 expression is inhibited by SIRT6, which depends upon deacetylating H3K9ac. Finally, our results reveal that SIRT6 inhibits glioma cell proliferation and colony formation in vitro and glioma cell growth in vivo in a PCBP2 dependent manner. In summary, our findings implicate that SIRT6 inhibits PCBP2 expression through deacetylating H3K9ac and SIRT6 acts as a tumor suppressor in human glioma.

Long Noncoding RNA miR210HG as a Potential Biomarker for the Diagnosis of Glioma.

Background Glioma remains a diagnostic challenge because of its variable clinical presentation and a lack of reliable screening tools. Long noncoding RNAs (lncRNAs) regulate gene function in a wide range of pathophysiological processes and are therefore emerging biomarkers for prostate cancer, hepatic cancer, and other tumor diseases. However, the effective use of lncRNAs as biomarkers for the diagnosis of glioma remains unproven. Methods This study included 42 glioma patients and 10 healthy controls. lncRNA and mRNA microarray chips were used to identify dysregulated lncRNAs in tumor tissue and tumor-adjacent normal tissue, and SYBR Green–based miRNA quantitative real-time reverse transcription polymerase chain reactions were used to validate upregulated lncRNAs. A receiver operating characteristic curve analysis was conducted to evaluate the diagnostic accuracy of the lncRNA identified as the candidate biomarker. Results miR210HG levels were significantly higher in tumor tissue than in tumor-adjacent normal tissue in participating glioma patients. Serum miR210HG levels were also significantly higher in glioma patients than in healthy controls. The receiver operating characteristic curve showed that serum miR210HG was a specific diagnostic predictor of acute pulmonary embolism with an area under the curve of 0.8323 (95% confidence interval, 0.7347 to 0.9299, p < 0.001). Conclusion Our findings indicate that miR210HG could be an important biomarker for the diagnosis of glioma, and, as such, large-scale investigations are urgently needed to pave the way from basic research to clinical use.

Leptin promotes human glioblastoma growth through activating Signal Transducers and Activators of Transcription 3 signaling.

Leptin plays an important role in cancer development and progression. However, its role on human glioblastoma cell line U87 growth and the underlying mechanism remains unexplored. In this study, we assessed the effect of leptin on U87 cells proliferation in vitro and in vivo, elucidating its underlying mechanism. The results showed that leptin significantly promoted U87 tumor cells growth in a time-and-dose-dependent manner. Leptin increased cell DNA synthesis and promoted G(0)/G(1) phase to S phase transition, but without any influence on cell apoptosis. In addition, leptin treatment resulted in phosphorylation of Signal Transducers and Activators of Transcription 3 (STAT3) on Tyr705, the key transcription factor in Janus-Activated Kinase (JAK)/STAT3 signaling pathway. All the data suggest that the JAK/STAT3 signaling pathway may be involved in promoting U87 glioblastoma growth mediated by leptin, which may be a target for anti-neoplastic treatments for glioblastoma.

Bioinformatic analysis of microRNA expression in Parkinson's disease.

Parkinsons disease (PD) is a type of movement disorder caused by loss of dopamine‑producing neurons in the midbrain. In order to identify the synergistic microRNA (miRNA) pattern in PD, miRNA and mRNA double expression profiles of PD were downloaded. Differentially expressed miRNA and mRNA were identified [P<0.01, following false discovery rate (FDR) correction]. A cumulative hypergeometric distribution test was then performed to identify synergistic miRNAs (P<0.01, following FDR correction). Gene ontology (GO) function and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway annotations were performed to analyze the miRNA regulatory target genes. Subsequently, a synergistic miRNA network was constructed and miRNAs exhibiting a high degree were identified. In total, 200 differentially expressed miRNA and 2,966 differentially expressed mRNA were identified. In addition, 1,502 synergistic miRNA interactions were identified, and miRNAs regulated 304 target genes in total. The GO and KEGG analysis demonstrated that these target genes were enriched in biosynthetic and cellular biosynthetic processes, the assembly of cellular components in morphogenesis, mitogen‑activated protein kinase signaling, myometrial relaxation and contraction pathways as well as calcium regulation. The miRNA network demonstrated that miR‑627, miR‑634, miR‑514, miR‑563 and miR‑613 had a high degree. miRNA with a high degree may be associated with the pathogenesis of PD and, therefore, may assist in the diagnosis and therapy of PD.

Endovascular Treatment of Ruptured Large or Wide-Neck Basilar Tip Aneurysms Associated with Moyamoya Disease Using the Stent-Assisted Coil Technique

BACKGROUND Endovascular coiling is preferred to surgical clipping for the treatment of basilar tip aneurysms (BTAs) associated with moyamoya disease (MMD). However, there are few reports addressing the safety of stent treatment of aneurysms located on unaffected arteries in MMD patients. We report our experiences of stent-assisted coil embolization for ruptured large or wide-neck BTAs associated with MMD. METHODS A retrospective review was conducted of 5 patients with ruptured BTAs associated with MMD treated by stent-assisted coil from January 2010 to December 2013 in our hospital. All presented with subarachnoid hemorrhage, and the diagnosis was confirmed by digital subtraction angiography. The procedure-related complications, immediate angiographic results, and clinical and angiographic follow-ups were analyzed. RESULTS Successful embolization was performed without procedure-related complications in all 5 patients, of whom 3 were treated by single stent-assisted coiling, and the others were treated by Y-configured stent technique. Immediate angiographic results showed complete occlusion in 2 patients, neck residual in 1, and partial occlusion in 2. Postoperative angiographic follow-ups were obtained in all 5 cases at a mean time of 17.6 ± 9.3 months (range, 6-28 months). Follow-up angiographic examinations demonstrated total occlusion without in-stent restenosis in all cases, and all the patients reported good outcomes (modified Rankin Scale score, 0-2). CONCLUSIONS Endovascular embolization using stent-assisted coiling proved to be a safe and efficient treatment for ruptured large or wide-neck BTAs associated with MMD; however, the long-term safety still remains to be confirmed.

EPCs-Collagen Sponge Complex Promotes Neovascularization of Chronic Cerebral Ischemia following Multiple Burr Hole (MBH) Surgery

Objective: The aim of this study was to explore the effect of endothelial progenitor cells (EPCs)-collagen sponge complex on the neovascularization of chronic cerebral ischemia following multiple burr hole (MBH) surgery. Methods: Bone marrow-derived EPCs from 5 Fisher 344 (F344) inbred rats were cultured and amplified in vitro, then co-cultured to become the EPCs-collagen sponge complex. Chronic cerebral hypo-perfusion was induced in 30 inbred male F344 rats by permanent bilateral internal carotid artery occlusion (BICAO). The MBH operation was performed three days after BICAO surgery. Rats were then randomly divided into 3 groups (n=10 each group); EPCs-collagen sponge complex + MBH; collagen sponge + MBH and MBH group. Either EPCs-collagen sponge complex or collagen sponge was implanted at the burr hole site in the EPCs-collagen sponge complex + MBH and the collagen sponge + MBH group, respectively. Regional cerebral blood flow (rCBF) was measured by Laser Doppler Flowmetry (LDF), EPCs were tracked by fluorescein, and immune-histochemical analysis for the neovascularization was performed 21 days after MBH surgery. Results: Before the MBH surgery, no differences of rCBF between the EPCs-collagen sponge complex + MBH group, the collagen sponge + MBH group and the MBH alone group (P>0.05) were found. The increase of rCBF in the EPCs-collagen sponge complex + MBH group (20.29 ± 10.21%) was significantly higher when compared with the other two groups 21 days after MBH surgery (7.39 ± 6.85% and 10.32 ± 6.27%, respectively; P<0.05). The amount of new blood vessels in the EPCs-collagen sponge complex + MBH group was also significantly greater than the other two groups (78.2 ± 4.7 vs. 48.7 ± 6.1 vs. 46.9 ± 7.3; P<0.05). The labeled EPCs were incorporated into the endothelial cells of vessels at the burr hole sites. Conclusion: The EPCs-collagen sponge complex enhances angiogenesis after MBH surgery under chronic cerebral hypo-perfusion condition, and increases the blood flow perfusion in ischemic cerebral tissue.