• Asian Pacific Journal of Cancer Prevention
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• v.14 no.2
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• pp.765-768
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• 2013

Background and Aims: Prostate cancer is the most commonly diagnosed cancer in males in many populations. Metformin is the most widely used anti-diabetic drug in the world, and there is increasing evidence of a potential efficacy of this agent as an anti-cancer drug. Metformin inhibits the proliferation of a range of cancer cells including prostate, colon, breast, ovarian, and glioma lines. MicroRNAs (miRNAs) are a class of small, non-coding, single-stranded RNAs that downregulate gene expression. We aimed to evaluate the effects of metformin treatment on changes in miRNA expression in PC-3 cells, and possible associations with biological behaviour. Materials and Methods: Average cell viability and cytotoxic effects of metformin were investigated at 24 hour intervals for three days using the xCELLigence system. The $IC_{50}$ dose of metformin in the PC-3 cells was found to be 5 mM. RNA samples were used for analysis using custom multi-species microarrays containing 1209 probes covering 1221 human mature microRNAs present in miRBase 16.0 database. Results: Among the human miRNAs investigated by the arrays, 10 miRNAs were up-regulated and 12 miRNAs were down-regulated in the metformin-treated group as compared to the control group. In conclusion, expression changes in miRNAs of miR-146a, miR-100, miR-425, miR-193a-3p and, miR-106b in metformin-treated cells may be important. This study may emphasize a new role of metformin on the regulation of miRNAs in prostate cancer.

• Journal of Life Science
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• v.13 no.6
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• pp.924-932
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• 2003

Epigallocatechin-3 Gallate (EGCG), a major constituent of green tea, has attracted increasing interest because of its many reported health benefits. Here we demonstrate for the first time that EGCG stimulates phospholipase D (PLD) activity in U87 human astroglioma cells. EGCG-induced PLD activation was abolished by the phospholipase C (PLC) inhibitor and a lipase inactive PLC-\gama1$ mutant, and was dependent on intracellular $Ca^{ 2+}$, and possibly involved $Ca^{ 2+}$ calmodulin-dependent protein kinase II (CaM kinase II). Interestingly, EGCG induced translocation of PLC-\gama1$ from the cytosol to the membrane and PLC-\gama1$interaction with PLD1. Taken together, these results demonstrate for the first time that in human astroglioma cells, EGCG regulates PLD activity via a signaling pathway involving a PLC-\gama1$ (inositol 1,4,5-trisphosphate-$Ca^{ 2+}$)-CaM kinase II-PLD pathway.

• Journal of Physiology & Pathology in Korean Medicine
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• v.20 no.5
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• pp.1249-1253
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• 2006

The fractions of Capsosiphon fulvescens were studied to verify the anticancer and immunostimulating activity. The fractions from the ethanol extract of C. fulvescens were prepared by the systematic extraction procedure with the solvents such as hexane, ethyl ether, methanol, butanol and H$_2$O. The cytotoxic effects of C. fulvescens fractions against human leukemia cell line U937, mouse neuroblastoma cell line (NB41A3), human hepatoma cell line (HepG2)and rat glioma cell line (C6) were investigated. Ethyl ether fraction of C. fulvescens showed the highest cytotoxicity against all four cell lines tested. In addition, H$_2$O fraction also showed relatively high cytotoxicity. Dose dependent patterns were observed on all four cell lines. The immune-stimulating effects of C. fulvescens fractions on rat macrophage cell line (RAW 264.7) were also investigated. All five fractions of C. fulvescens extract stimulated NO production with concentration dependant manner. These results suggest that C. fulvescens may be a useful candidate for a natural antitumor and immune-stimulating agent.

• Biomolecules & Therapeutics
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• v.28 no.5
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• pp.423-430
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• 2020

Telmisartan is an angiotensin-II receptor blocker and acts as a selective modulator of peroxisome proliferator-activated receptor gamma (PPARγ). Several studies have demonstrated that telmisartan ameliorates depression and memory dysfunction and reduces brain inflammation. We hypothesized that the beneficial effects of telmisartan on brain could be due to modulation of the blood-brain barrier (BBB) function. Here, we examined the effect of telmisartan on tumor necrosis factor alpha (TNF-α)-induced expression of intercellular adhesion molecule 1 (ICAM-1) which plays an important role in leukocyte transcytosis through the BBB. Telmisartan blocked TNF-α-induced ICAM-1 expression and leukocyte adhesion in U87MG human glioma cells but showed no effect on human brain microvascular endothelial cells. In U87MG cells, a PPAR antagonist, GW9662 did not block the effect of telmisartan on ICAM1 expression but rather potentiated. Moreover, GW9662 caused no change in TNF-α-induced ICAM-1 expression, suggesting no implication of PPARγ in the telmisartan effect. Further studies showed that telmisartan blocked TNF-α-induced activation of c-Jun N-terminal kinase (JNK), extracellular signal-regulated kinase 1/2 (ERK1/2), p38, and nuclear factorkappa B (NF-κB). In contrast, inhibitors of JNK, ERK1/2 and NF-κB but not p38, blocked ICAM-1 expression induced by TNF-α. Thus, our findings suggest that the beneficial effect of telmisartan is likely due to the reduction of astrocytic ICAM1 expression and leukocytes adhesion to astrocytes, and that this response was mediated by the inhibition of JNK/ERK1/2/NF-κB activation and in the PPAR-independent manner. In conclusion, this study enhances our understanding of the mechanism by which telmisartan exerts the beneficial brain function.

• Journal of Korean Neurosurgical Society
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• v.48 no.1
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• pp.20-30
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• 2010

Objective : We determined whether the expression of GRIM-19 is correlated with pathologic types and malignant grades in gliomas, and determined the function of GRIM-19 in human gliomas. Methods : Tumor tissues were isolated and frozen at $-80^{\circ}C$ just after surgery. The tissues consisted of normal brain tissue (4), astrocytomas (2), anaplastic astrocytomas (2), oligodendrogliomas (13), anaplastic oligodendrogliomas (11), and glioblastomas (16). To profile tumor-related genes, we applied RNA differential display using a $Genefishing^{TM}$ DEG kit, and validated the tumor-related genes by reverse transcription polymerase chain reaction (RT-PCR). A human glioblastoma cell line (U343MG-A) was used for the GRIM-19 functional studies. The morphologic and cytoskeletal changes were examined via light and confocal microscopy. The migratory and invasive abilities were investigated by the simple scratch technique and Matrigel assay. The antiproliferative activity was determined by thiazolyl blue Tetrazolium bromide (MTT) assay and FACS analysis. Results : Based on RT-PCR analysis, the expression of GRIM-19 was higher in astrocytic tumors than oligodendroglial tumors. The expression of GRIM-19 was higher in high-grade tumors than low-grade tumors or normal brain tissue; glioblastomas showed the highest expression. After transfection of GRIM-19 into U343MG-A, the morphology of the sense-transfection cells became larger and more spindly. The antisensetransfection cells became smaller and rounder compared with wild type U343MG-A. The MTT assay showed that the sense-transfection cells were more sensitive to the combination of interferon-$\beta$ and retinoic acid than U343MG-A cells or antisense-transfection cells; the antiproliferative activity was related to apoptosis. Conclusion : GRIM-19 may be one of the gene profiles which regulate cell death via apoptosis in human gliomas.

• Journal of Life Science
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• v.16 no.4
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• pp.691-698
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• 2006

Phospholipase D (PLD) is known to play an important role in a variety of cells. However, little is known about $CoCl_2-mediated$ PLD signaling. In this study we demonstrated for the first time that $CoCl_2$ stimulates PLD activity and increases expression of cyclooxygenase-2 (COX-2), which is known to mediate inflammatory reaction. $CoCl_2-induced$ PLD activity was assessed by measuring the formation of $[^3H]$ phosphatidylbutanol (PtdBut), the product of PLD-mediated transphosphatidylation, in the presence of 1-butanol. To study mechanism of PLD signaling induced by $CoCl_2$, U87 human glioblastoma cells were stimulated by $CoCl_2$ and regulators of PLD activity induced by $CoCl_2$ were investigated using several inhibitors of signaling proteins. Moreover, PLD activation by $CoCl_2$ increased not only expression of COX-2 protein but also COX-2 promoter activity. In summary, these results suggest that $CoCl_2$ increases expression of COX-2 protein via PLD in human U87 glioblastoma cells.

• The Korean Journal of Physiology
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• v.29 no.2
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• pp.301-307
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• 1995

To explore electrophysiological properties of the ${\delta}-Opioid$ receptors artificially expressed in the mammalian cell, effect of an opioid agonist DPDPE $(1\;{\mu}M)$ on the voltage-sensitive outward currents was examined in the HEK293 (human embryonic kidney) cells transfected with ${\delta}-Opioid$ receptor cDNA cloned from NG-108-15 $(neuroblastoma\;{\times}\;glioma\;hybrid)$ cDNA library. Also studied were effects of 8-bromo-cyclic AMP and naloxone on DPDPE-induced changes in the voltage sensitive outward current. The voltage sensitive outward currents were recorded using perforated patch technique at room temperature. In the non-transformed HEK293 cells, DPDPE did not alter voltage sensitive outward current, indicating that no native ${\delta}-Opioid$ receptor had been developed. However, $(1\;{\mu}M)$ DPDPE remarkably increased the voltage sensitive outward current in the transformed HEK293 cells. The increment in voltage sensitive outward current peaked in $7{\sim}10\;minutes$ after DPDPE application, and the maximum DPDPE-activated outward current $(313.1{\pm}12.3\;pA)$ was recorded when the membrane potential was depolarized to +70mv. Following pretreatment of the transformed HEK293 cells with 1 mM 8-bromo-cyclic AMP, DPDPE failed to increase the voltage sensitive outward currents. On the other hand, naloxone completely abolished DPDPE-activated voltage sensitive outward current in the transformed HEK293 cells. The results of present study suggest that in the transformed HEK293 cells an activation of the ${\delta}-Opioid$ receptors by an opioid agonist DPDPE increases the voltage-sensitive potassium current as a result of decrement in cyclic AMP level.

• KSBB Journal
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• v.23 no.2
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• pp.142-146
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• 2008

In order to sprout and migrate, cells must secrete proteinases which are degrading the surrounding extracellular matrix. In this study, we examined the effect of mulberry extracts and combination of mulberry extracts and VEGF on human malignant glioma U-373-MG cells. Mulberry extracts induced the secretion of matrix metalloproteinase-9 (MMP-9) and suppressed the secretion of MMP-2 and plasmin. Mulberry extracts inhibited the VEGF-induced MMP-2, MMP-9 and plasmin secretion. It is therefore, suggested that mulberry extracts can suppress the VEGF-induced tumor angiogenesis in U-373-MG cells. Also, mulberry extracts induced the secretion of MMP-9 and plasmin through PI 3'-kinase pathway in U-373-MG cells.

• Molecules and Cells
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• v.40 no.10
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• pp.761-772
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• 2017

Glioblastoma is the most frequent and most aggressive brain tumor in adults. Solute carrier family 8 member 2 (SLC8A2) is only expressed in normal brain, but not present in other human normal tissues or in gliomas. Therefore, we hypothesized that SLC8A2 might be a glioma tumor suppressor gene and detected the role of SLC8A2 in glioblastoma and explored the underlying molecular mechanism. The glioblastoma U87MG cells stably transfected with the lentivirus plasmid containg SLC8A2 (U87MG-SLC8A2) and negative control (U87MG-NC) were constructed. In the present study, we found that the tumorigenicity of U87MG in nude mice was totally inhibited by SLC8A2. Overexpression of SLC8A2 had no effect on cell proliferation or cell cycle, but impaired the invasion and migration of U87MG cells, most likely through inactivating the extracellular signal-related kinases (ERK)1/2 signaling pathway, inhibiting the nuclear translocation and DNA binding activity of nuclear factor kappa B ($NF-{\kappa}B$), reducing the level of matrix metalloproteinases (MMPs) and urokinase-type plasminogen activator (uPA)-its receptor (uPAR) system (ERK1/2-$NF-{\kappa}B$-MMPs/uPA-uPAR), and altering the protein levels of epithelial to mesenchymal transitions (EMT)-associated proteins E-cardherin, vimentin and Snail. In addition, SLC8A2 inhibited the angiogenesis of U87MG cells, probably through combined inhibition of endothelium-dependent and endothelium-nondependent angiogenesis (vascular mimicry pattern). Totally, SLC8A2 serves as a tumor suppressor gene and inhibits invasion, angiogenesis and growth of glioblastoma.

• Biomolecules & Therapeutics
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• v.20 no.1
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• pp.68-74
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• 2012

Anthocyanins have received growing attention as dietary antioxidants for the prevention of oxidative damage. Astrocytes, which are specialized glial cells, exert numerous essential, complex functions in both healthy and diseased central nervous system (CNS) through a process known as reactive astrogilosis. Therefore, the maintenance of glial cell viability may be important because of its role as a key modulator of neuropathological events. The aim of this study was to investigate the effect of anthocyanin on the survival of glial cells exposed to oxidative stress. Our results demonstrated that anthocyanin extracts from black soybean increased survival of U87 glioma cells in a dose dependent manner upon oxygen-glucose deprivation (OGD), accompanied by decrease levels of reactive oxygen species (ROS). While treatment cells with anthocyanin extracts or OGD stress individually activated autophagy induction, the effect was signifi cantly augmented by pretreatment cells with anthocyanin extracts prior to OGD. The contribution of autophagy induction to the protective effects of anthocyanin was verifi ed by the observation that silencing the Atg5 expression, an essential regulator of autophagy induction, reversed the cytoprotective effect of anthocyanin extracts against OGD stress. Treatment of U87 cells with rapamycin, an autophagy inducer, increased cell survival upon OGD stress comparable to anthocyanin, indicating that autophagy functions as a survival mechanism against oxidative stress-induced cytotoxicity in glial cells. Our results, therefore, provide a rationale for the use of anthocyanin as a preventive agent for brain dysfunction caused by oxidative damage, such as a stroke.