Long Non-coding RNA EPIC1 Promotes Cell Proliferation and Motility and Drug Resistance in Glioma.

Evidence has revealed that long non-coding RNAs (lncRNAs) are involved in carcinogenesis and tumor progression. lncRNAs play an important role in regulation of numerous cellular processes including cell proliferation, apoptosis, cell cycle, differentiation, and motility. Several studies have demonstrated that lncRNA EPIC1 governs cell growth, cell cycle, migration, invasion, and drug resistance in human malignancies. However, the role of EPIC1 and its underlying molecular mechanisms in glioma have not been investigated. In this study, we determined the function of EPIC1 in glioma cells via upregulation or downregulation of EPIC1. We further dissected the mechanism of EPIC1-mediated tumor progression in glioma. Our results showed that inhibition of EPIC1 suppressed cell viability, induced apoptosis, inhibited cell invasion, and increased cell sensitivity to temozolomide in glioma cells. Consistently, overexpression of EPIC1 exhibited the opposite effects in glioma cells. Moreover, our data suggest that EPIC1 exerts its biological functions via targeting Cdc20 in glioma cells. In line with this, overexpression of Cdc20 reversed the EPIC1-mediated tumor progression in glioma cells. Therefore, targeting EPIC1 might be a useful approach for glioma treatment.

MicroRNA-365 suppressed cell proliferation and migration via targeting PAX6 in glioblastoma.

MicroRNAs (miRNAs) act an important role in the progression of tumor. In this study, we showed that the serum expression of miR-365 was downregulated in the glioblastoma compared with in the healthy controls. We also demonstrated that miR-365 expression was downregulated in glioblastoma tissues compared with the adjacent normal tissues. Overexpression of miR-365 suppressed the glioblastoma cell proliferation and migration. Moreover, ectopic expression of miR-365 promoted the expression of Ecadherin while inhibited the expression of N-cadherin and Vimentin in U87 cell. Furthermore, we identified PAX6 as a direct target gene of miR-365 in U87 cell. Overexpression of miR-365 suppressed glioblastoma cell proliferation and migration and epithelial-to-mesenchymal transition through inhibiting PAX6 expression. These results suggested that miR-365 played a tumor suppressor in glioblastoma.

Cdc20 overexpression is involved in temozolomide-resistant glioma cells with epithelial-mesenchymal transition.

Glioma remains one of the most aggressive and lethal cancers in central nervous system. Temozolomide (TMZ) is the most commonly used chemotherapeutic agent in gliomas. However, therapeutic benefits of TMZ could be very limited and all patients would finally suffer from tumor progression as the tumors develop resistance to TMZ. In this study, we aim to investigate the underlying mechanism of chemoresistance in glioma cell line and to identify whether there is still a close link between epithelial-mesenchymal transition (EMT) and TMZ resistance in gliomas. The real-time RT-PCR and Western blotting were used to measure the expression of EMT markers in TMZ-resistant cells. The migration and invasion assays were conducted to detect the cell motility activity in TMZ-resistant cells. The transfection was used to down-regulate the Cdc20 expression. The student t-test was applied for data analysis. We established stable TMZ-resistant glioma cells and designated as TR. Our results revealed that TR cells exhibited a significantly increased resistance to TMZ compared with their parental cells. Moreover, TMZ-resistant cells had acquired EMT-like changes. For the mechanism study, we measured a significant increased expression of CDC20 and decreased expression of Bim in TR cells. Moreover, upon suppression of CDC20 by shRNA transfection, TR cells underwent a reverse of EMT features. Importantly, knockdown of CDC20 enhanced the drug sensitivity of TR cells to TMZ. Our results suggested that inactivation of CDC20 could contribute to the future therapy that possibly overcomes drug resistance in human cancers.

Antagomirs Targeting MicroRNA-134 Increase Limk1 Levels After Experimental Seizures in Vitro and in Vivo.

BACKGROUND: MiR-134 is enriched in dendrites of hippocampal neurons and plays crucial roles in the progress of epilepsy. The present study aims to investigate the effects of antagomirs targeting miroRNA-134 (Ant-134) on limk1 expression and the binding of miR-134 and limk1 in experimental seizure. METHODS: Status epilepticus (SE) rat model was established by lithium chloride-pilocarpine injection and was treated with Ant-134 by intracerebroventricular injection. Low Mg2+-exposed primary neurons were used as an in vitro model of SE. The expression of miR-134 was determined using real-time PCR. Protein expressions of limk1 and cofilin were determined by Western blotting. Luciferase reporter assay was used to examine the binding between miR-134 and limk1 3'-untranslated region. RESULTS: The expression of miR-134 was markedly enhanced in hippocampus of the SE rats and low Mg2+-exposed neurons. Ant-134 increased the expression of limk1 and reduced the expression of cofilin in the SE hippocampus and Low Mg2+-exposed neurons. In addition, luciferase reporter assay confirmed that miR-134 bound limk1 3'-UTR. MiR-134 overexpression inhibited limk1 mRNA and protein expressions in neurons. CONCLUSION: Blockage of miR-134 upregulates limk1 expression and downregulated cofilin expression in hippocampus of the SE rats. This mechanism may contribute to the neuroprotective effects of Ant-134.

Cyclophilin A Maintains Glioma-Initiating Cell Stemness by Regulating Wnt/ß-Catenin Signaling.

Purpose: Glioma-initiating cells (GIC) are glioma stem-like cells that contribute to glioblastoma (GBM) development, recurrence, and resistance to chemotherapy and radiotherapy. They have recently become the focus of novel treatment strategies. Cyclophilin A (CypA) is a cytosolic protein that belongs to the peptidyl-prolyl isomerase (PPIase) family and the major intracellular target of the immunosuppressive drug cyclosporin A (CsA). In this study, we investigate the functions of CypA and its mechanism of action in GICs' development.Experimental Design: We analyzed differences in CypA expression between primary tumors and neurospheres from the GDS database, both before and after GIC differentiation. A series of experiments was conducted to investigate the role of CypA in GIC stemness, self-renewal, proliferation, radiotherapy resistance, and mechanism. We then designed glutathione S-transferase (GST) pulldown and coimmunoprecipitation assays to detect signaling activity.Results: In this study, we demonstrated that CypA promotes GIC stemness, self-renewal, proliferation, and radiotherapy resistance. Mechanistically, we found that CypA binds ß-catenin and is recruited to Wnt target gene promoters. By increasing the interaction between ß-catenin and TCF4, CypA enhances transcriptional activity.Conclusions: Our results demonstrate that CypA enhances GIC stemness, self-renewal, and radioresistance through Wnt/ß-catenin signaling. Due to its promotive effects on GICs, CypA is a potential target for future glioma therapy. Clin Cancer Res; 23(21); 6640-9. ©2017 AACR.

Antagomirs Targeting MiroRNA-134 Attenuates Epilepsy in Rats through Regulation of Oxidative Stress, Mitochondrial Functions and Autophagy.

The effects of the existing anti-epileptic drugs are unsatisfactory to almost one third of epileptic patients. MiR-134 antagomirs prevent pilocarpine-induced status epilepticus. In this study, a lithium chloride-pilocarpine-induced status epilepticus model was established and treated with intracerebroventricular injection of antagomirs targeting miR-134 (Ant-134). The Ant-134 treatment significantly improved the performance of rats in Morris water maze tests, inhibited mossy fiber sprouting in the dentate gyrus, and increased the survival neurons in the hippocampal CA1 region. Silencing of miR-134 remarkably decreased malonaldehyde and 4-hydroxynonenal levels and increased superoxide dismutase activity in the hippocampus. The Ant-134 treatment also significantly increased the production of ATP and the activities of mitochondrial respiratory enzyme complexes and significantly decreased the reactive oxygen species generation in the hippocampus compared with the status epilepticus rats. Finally, the Ant-134 treatment remarkably downregulated the hippocampal expressions of autophagy-associated proteins Atg5, beclin-1 and light chain 3B. In conclusion, Ant-134 attenuates epilepsy via inhibiting oxidative stress, improving mitochondrial functions and regulating autophagy in the hippocampus.

Pep-1 peptide-functionalized liposome to enhance the anticancer efficacy of cilengitide in glioma treatment.

In this study, we have established an effective and novel nanocarrier system for the effective treatment of glioma. We have established the glioma tissue penetrating nanocarrier system by conjugating Pep-1 as a targeting ligand on the liposome surface to enhance the anticancer efficacy of cilengitide (CGL). The particles were nanosized and exhibited a controlled release of drug in both the pH conditions. The cellular uptake assay showed that conjugation of Pep-1 on the liposome surface remarkably increased the cellular uptake. The uptake of CGT-loaded Pep-1 peptide-conjugated liposome (PeCNL) increased to 89.8% compared to 47.5% for CNL indicating the efficient internalization of the nanocarriers. Consistently, PeCNL exhibited a significantly higher cytotoxic effect in cancer cells compared to that of non-targeted CGT-loaded liposome (CNL). PeCNL exhibited a higher apoptosis of cancer cells (∼35%) compared to that of CNL. Most importantly, PeCNL exhibited a significantly superior anticancer effect with tumor volume as low as ∼350mm3 indicating the superior anticancer potential of targeted formulations. Similarly, PeCNL showed the lowest staining for Ki67 indicating that the targeted NP has the maximum effect in controlling the proliferation of cancer cells. Taken together, Pep-1 conjugated liposome could exhibit better antitumor efficacy when applied to IL-13R2 receptor overexpressed specific brain glioma.

Genipin Inhibits LPS-Induced Inflammatory Response in BV2 Microglial Cells.

Genipin, an aglycon of geniposide, has been reported to have anti-inflammatory effect. However, the anti-inflammatory activity of genipin on LPS-stimulated BV2 microglial cells has not been reported. In this study, we investigated the molecular mechanisms responsible for the anti-inflammatory activity of genipin both in vivo and in vitro. The levels of TNF-α, IL-1ß, NO and PGE2 were detected by ELISA. The expression of Nrf2, HO-1, and NF-κB were detected by western blot analysis. In vivo, genipin significantly attenuated LPS-induced memory deficit in the Morris water maze and passive avoidance tasks. Genipin also inhibited LPS-induced TNF-α and IL-1ß expression in brain tissues. In vitro, our results showed that genipin inhibited LPS-induced TNF-α, IL-1ß, NO and PGE2 production in a concentration-dependent manner. Genipin also suppressed LPS-induced NF-κB activation. In addition, the expression of Nrf2 and HO-1 were up-regulated by treatment of genipin. Furthermore, the inhibition of genipin on inflammatory mediator production was attenuated by transfection with Nrf2 siRNA. In conclusion, genipin inhibited LPS-induced inflammatory response by activating Nrf2 signaling pathway in BV2 microglia.

Mild hypothermia protects against early brain injury in rats following subarachnoid hemorrhage via the TrkB/ERK/CREB signaling pathway.

Subarachnoid hemorrhage (SAH) is a severe neurological disease, which is associated with a significant number of cases of premature mortality and disability worldwide. Mild hypothermia (MH) has been proposed as a potential therapeutic strategy to reduce neuronal injury following SAH. The present study aimed to investigate the mechanisms of MH's protective role in the process of SAH. The present study demonstrated that MH was able to protect against early brain injury in a rat model of SAH. Treating SAH rats with MH reduced the release of reactive oxygen species and prevented activation of apoptotic cascades. Furthermore, the protective effects of MH were shown to be mediated by enhanced activity of the tropomyosin receptor kinase B/extracellular signal­regulated kinases/cAMP response element binding protein (TrkB/ERK/CREB) pathway. Inhibition of TrkB/ERK/CREB activity using a small molecule inhibitor largely abolished the beneficial effects of MH in SAH rats. These results outline an endogenous mechanism underlying the neuroprotective effects of MH in SAH.

MicroRNA-300 inhibited glioblastoma progression through ROCK1.

Glioblastoma is a common type of brain aggressive tumors and has a poor prognosis. MicroRNAs (miRNAs) are a class of small, endogenous and non-coding RNAs that play crucial roles in cell proliferation, survival and invasion. Deregulated expression of miR-300 has been studied in a lot of cancers. However, the role of miR-300 in glioblastoma is still unknown. In this study, we demonstrated that miR-300 expression was downregulated in glioblastoma tissues compared with the normal tissues. Lower expression level of miR-300 was observed in thirty cases (75 %, 30/40) of glioblastoma samples compared with the normal samples. Moreover, the overall survival of glioblastoma patients with lower miR-300 expression level was shorter than those with higher miR-300 expression level. In addition, miR-300 expression was also downregulated in glioblastoma cell lines. Overexpression of miR-300 inhibited cell proliferation, cell cycle and invasion in glioblastoma cell line U87 and U251. Moreover, we identified ROCK1 as a direct target of miR-300 in U87 and U251 cells. Overexpression of ROCK1 partially rescued the miR-300-mediated cell growth. ROCK1 expression levels in glioblastoma tissues were higher than that in normal tissues. ROCK1 expression levels were higher in thirty-one cases of glioblastoma samples than their normal samples. Furthermore, the expression level ROCK1 was inversely correlated with the expression level of miR-300. Importantly, overexpression of miR-300 suppressed glioblastoma progression in an established xenograft model. In conclusion, we revealed that miR-300 might act as a tumor suppressor gene through inhibiting ROCK1 in glioblastoma.

Hsa-miR-495 acts as a tumor suppressor gene in glioma via the negative regulation of MYB.

MicroRNAs (miRNAs) are small non-coding RNA molecules that regulate gene expression at the post-transcriptional level. Previous studies have reported that there are causative links between the abnormal regulation of miRNAs and cancer development. Hsa­miR­495 has previously been demonstrated to be downregulated, and to function as a tumor suppressor, in numerous types of human cancer. However, the function and molecular mechanism of hsa­miR­495 in glioma remains unclear. In the current study, the expression and effects of hsa­miR­495 on glioma were evaluated. It was identified that the expression levels of hsa-miR-495 were downregulated in glioma tissues and cell lines. Furthermore, restoration of hsa-miR-495 inhibited glioma cell proliferation and invasion in vitro. Notably, a luciferase reporter assay revealed that hsa­miR­495 was able to directly target v­myb avian myeloblastosis viral oncogene homolog (MYB) in glioma cells. In addition, an RNA interference assay indicated that MYB knockdown inhibited glioma cell proliferation and invasion in vitro. In conclusion, the results of the present study suggested that hsa­miR­495 may act as a tumor suppressor gene in glioma by directly inhibiting MYB expression, which may provide a novel therapeutic strategy for the treatment of glioma.

miR-590-3p suppresses cancer cell migration, invasion and epithelial-mesenchymal transition in glioblastoma multiforme by targeting ZEB1 and ZEB2.

Invasion and migration of glioblastoma multiforme (GBM) is a multistep process and an important phenotype that causes this disease to invade surrounding tissues in the brain. The purpose of this study was to determine the role of miR-590-3p in regulation of epithelial mesenchymal transition (EMT) and metastasis of GBM cells. Expression levels of miR-590-3p in 15 GBM specimens with adjacent tissues and five GBM cell lines were assessed by quantitative RT-PCR. We found that miR-590-3p was down-regulated in detected GBM tissue samples and all of the GBM cell lines. In addition, Ectopic expression of miR-590-3p suppressed and miR-590-3p-in promoted EMT, migration, and invasion in U87MG and A172 cells. Bioinformatics coupled with luciferase and Western blot assays also revealed that miR-590-3p inhibited expression of ZEB1 and ZEB2, which are master regulators of tumor metastasis. Our study first indicates that miR-590-3p functions as a suppressor of GBM EMT and metastasis by targeting ZEB1 and ZEB2, and it may be a therapeutic target for metastatic GBM.

Linalool Inhibits LPS-Induced Inflammation in BV2 Microglia Cells by Activating Nrf2.

Linalool, a natural compound of the essential oils, has been reported to have anti-inflammatory effects. This study aimed to investigate the anti-inflammatory effects and mechanism of linalool in LPS-stimulated BV2 microglia cells. BV2 microglia cells were stimulated with LPS in the presence or absence of linalool. The production of inflammatory mediators TNF-α, IL-1ß, NO, and PGE2 as well as Nrf2, HO-1 expression were detected. Our results showed that linalool inhibited LPS-induced TNF-α, IL-1ß, NO, and PGE2 production in a dose-dependent manner. Linalool also inhibited LPS-induced NF-κB activation. Treatment of linalool induced nuclear translocation of Nrf2 and expression of HO-1. In addition, our results showed that the anti-inflammatory effect of linalool was attenuated by transfection with Nrf2 siRNA. In conclusion, these results suggested that linalool inhibits LPS-induced inflammation in BV2 microglia cells by activating Nrf2/HO-1 signaling pathway.

miR-603 promotes glioma cell growth via Wnt/ß-catenin pathway by inhibiting WIF1 and CTNNBIP1.

Gliomas are the most common and deadly type of brain tumor. In spite of progressive treatments, patient prognosis has not improved significantly. MicroRNAs are considered promising candidates for glioma therapy. MiR-603 was found overexpressed in both glioma tissues and cell lines. MiR-603 promoted cell proliferation, cell cycle progression and neurosphere formation. Conversely, inhibition of miR-603 remarkably reduced these effects. We confirmed that WIF1 and CTNNBIP1 are bona fide targets of miR-603. The negative correlation between miR-603 and these molecules' expression was shown by Pearson correlation in 50 primary glioma tissue samples. Furthermore, overexpression of miR-603 promoted nuclear ß-catenin levels and TOPflash luciferase activity, indicating that miR-603 activates the Wnt/ß-catenin signaling pathway. Our in vivo results confirmed the positive role of miR-603 in glioma development. We demonstrate that miR-603 regulates glioma development via its WIF1 and CTNNBIP1 targets, which suggests that miR-603 may be a promising candidate for therapeutic applications in glioma treatment.

A sub-pathway based method to identify candidate drugs for glioblastomas.

Glioblastomas (GBM) are the most common primary malignant brain tumors with a high invasiveness and resistance to radiation and other treatments. The need for the development of new therapeutic agents for GBM is urgent. Here, we aimed to explore the metabolic mechanism of GBM and identified potential novel drugs for GBM by a sub-pathway-based method. By using the GBM microarray data from "The Cancer Genome Atlas" database, we first identified the 274 differentially expressed genes between GBM and normal samples. Then, we identified 18 significant enriched metabolic sub-pathways that may involve in the development of GBM. Finally, by an integrated analysis of GBM-involved sub-pathways and drug-affected sub-pathways, we identified 66 novel small-molecular drugs capable to target the GBM-involved sub-pathways. Our method could not only identify existing drug (paclitaxel) for GBM, but also predict potentially novel agents (pergolide) that might have therapeutic effects. We also experimentally verified that pergolide could induce GBM cell death. These candidate small-molecular drugs identified by our approach may provide insights into a novel therapy approach for GBM.

MiR-122/Wnt/ß-catenin regulatory circuitry sustains glioma progression.

Malignant glioma is the most common type of human intracranial cancer and has poor prognosis due to its high recurrence and invasiveness. However, the molecular mechanisms underlying its malignant phenotypes have still not been completely explored yet. miR-122 has been well documented to act as a tumor suppressor for hepatocellular carcinoma and breast cancer, but the implication of miR-122 in the progression of glioma is not clear yet. In this study, we found that miR-122 was underexpressed in glioma specimens and glioma cell lines, compared with normal brain tissues and cell lines. The expression of miR-122 levels is inversely correlated with the survival of patients after surgery. Overexpression of miR-122 by an adenoviral vector suppressed the proliferation and colony formation of glioma cells. The in vivo tumorigenicity of U-87 MG cells was also greatly compromised by restoring miR-122. miR-122 suppressed the activation of Wnt/ß-catenin pathway in glioma cells. Interestingly, Wnt/ß-catenin signaling conversely reduced the expression of miR-122 in glioma cells, maybe in a hepatocyte nuclear factor (HNF)-dependent mechanism. Taken together, we revealed that there is a miR-122/Wnt/ß-catenin regulatory circuitry existing in glioma cells that contributes to glioma progression.

Association between glutathione S-transferase T1 null genotype and glioma susceptibility: a meta-analysis.

The relationship between genetic polymorphisms of glutathione S-transferase (GST) and the development of glioma has been investigated in several epidemiologic studies. However, these studies report inconsistent results. In order to get this precise result, a meta-analysis was conducted by calculating the pooled odds ratios (OR) and the 95% confidence intervals (95 % CI). Eleven case-control research studies with a total of 2,416 glioma cases and 4,850 controls were included into this meta-analysis. The combined results based on all studies showed that there was no significant association between the GSTT1 null allele and glioma risk (OR = 1.188, 95% CI = 0.929­1.520, P(heterogeneity) = 0.003, P = 0.170). In the subgroup analysis, the same results were found in our work. There was no risk of publication bias in this meta-analysis. Our results suggest that GSTT1 null genotype was not associated with the increased risk of glioma.

Effects of tetrandrine on glioma cell malignant phenotype via inhibition of ADAM17.

Tetrandrine (TET), a bisbenzylisoquinoline alkaloid isolated from the root of Hang-Fang-Chi (Stephania tetrandra S. Moore), exhibits broad pharmacological effects, including antitumor activity in various malignant neoplasms. Recently, the beneficial effects of TET on cytotoxicity towards tumor cells, radiosensitization, circumventing multidrug resistance, normal tissue radioprotection, and antiangiogenesis have been examined extensively. However, the potential molecular mechanisms of the effect on glioma of TET are yet unknown. This study is explored to evaluate whether TET can inhibit cell proliferation, invasion, and the possible underlying mechanisms in glioma U87 cell. In the present study, cell proliferation was determined by using the Cell Counting Kit-8 (CCK-8) viability assay. The invasion and migration were evaluated by means of wound-scratch assay and Matrigel-Transwell methods. The mRNA expression and protein expression of ADAM metallopeptidase domain 17 (ADAM17) in glioma cell lines and glioma samples were determined by reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting, respectively. Moreover, the expression of epidermal growth factor receptor (EGFR)/p-EGFR and AKT/p-AKT was studied to clarify the molecular mechanism. Our results suggested that TET inhibited cell proliferation in a dose- and time-dependent manner, and cell migration and invasion in vitro. In addition, our results indicated that ADAM17 expression significantly increased in glioma compared to nontumored human brain tissue and according to the histopathological grade of glioma. Western blot analysis showed that protein expressions of ADAM17, p-EGFR, and p-AKT were inhibited by TET in U87 cells. These data also suggest that suppression of ADAM17 and downregulation of EGFR-phosphoinositide-3-kinase (PI3K)-AKT signaling pathways may contribute to TET-induced decrease of proliferation, migration, and invasiveness.

Sox11 modulates neocortical development by regulating the proliferation and neuronal differentiation of cortical intermediate precursors.

Neural precursor cells play important roles in the neocortical development, but the mechanisms of neural progenitor proliferation, neuronal differentiation, and migration, as well as patterning are still unclear. Sox11, one of SoxC family members, has been reported to be essential for embryonic and adult neurogenesis. But there is no report about the roles of Sox11 in corticogenesis. In order to investigate Sox11 function during cortical development, loss of function experiment was performed in this study. Knockdown of Sox11 by Sox11 siRNA constructs resulted in a diminished neuronal differentiation, but enhanced proliferation of intermediate progenitors. Accompanied with the high expression of Sox11 in the postmitotic neurons, but low expression of Sox11 in the dividing neural progenitors, all the observations indicate that Sox11 induces neuronal differentiation during the neocortical development.

Inhibitory effect of Pulsatilla chinensis polysaccharides on glioma.

Malignant glioma is a very devastating disease. Conventional surgery, radio-and chemotherapy are of limited benefit to improve the cure of patients with malignant astrocytomas. In this research, we evaluated the inhibitory effect of Pulsatilla chinensis polysaccharides (PCPS) on glioma in vivo and in vitro. PCPS had a significant anti-proliferative effect on C6 glioma in vitro assay. Meanwhile a remarkable inhibitory effect PCPS on the growth of C6 glioma and prolongation of life survival could be observed in vivo, comparable to carmustine (BCNU) administration. Moreover PCPS treatment to tumor bearing mice could not only decrease the body weight loss, but also elevate the thymus and spleen indices. In addition, PCPS administration to tumor bearing mice could relieve the liver and kidney damage with decreased levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT) and urea, and enhance superoxide dismutase (SOD) and catalase (CAT) enzyme activities with lower MDA levels in the plasma of tumor bearing mice. The above data proved that PCPS had strong antitumor activity and could be considered as a possible candidate drugs for the glioma therapy.