• Biomolecules & Therapeutics
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• 제8권2호
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• pp.140-146
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• 2000

Recently, we reported that immunostimulation of primary rat cortical astrocyte caused stimulation of glucose deprivation induced apoptotic cell death. To enhance the understanding of the mechanism of the potentiated cell death of clucose-deprived astrocyte by immunostimulation, we investigated the effect of immunostimulation on the glucose deprivation induced cell death of rat C6 glioma cells. Co-treatment of C6 glioma cells with lipopolysaccharide (LPS, $1\;{\mu}\textrm{g}/ml$) and interferon ${\gamma}(IFN{\gamma},\;100U/ml)$ is serum free condition caused marked elevationo f nitric oxide production ($>50\;{\mu}M$). In this condition, glucose deprivation caused significant release of lactate dehdrogenase (LDH) from C6 glioma cells while control cells did not show LDH release. To investigate whether elevated level of nitric oxide is responsible for the enhanced LDH release in glucose-deprived condition, C6 glioma cells were treated with 3-morphorinosydnonimine (SIN-1) and it was observed that SIN-1 caused increase in LDH release from glucose-deprived C6 glioma cells. Treatment of C6 glioma cells with $25\;{\mu}M$ of pyrrolidinedithiocarbamate (PDTC) which inhibit Nuclear factor kB (NF-kB) activation, caused complete inhibition of nitric oxide production. Treatment of C6 glioma cells with NO synthase inhibitors, $N^{G}$-nitro-L-arginine (NNA) or L-$N{\omega}$-nitro-L-arginine methyl ester (L-NAME), caused inhibition of nitric oxide production and also glucose deprivation induced cell death of cytokine-stimulated C6 glioma cells. In addition, diaminohydroxypyrimidine (DAHP, 5 mM) which inhibits the synthesis of tetrahydrobiopterine (BH4), one of essential cofactors for iNOS activity, caused complete inhibition of NO production from immunostimulated C6 glioma cells. The results from the present study suggest that immunostimulation causes potentiation of glucose deprivation induced death of C6 glioma cells which is mediated at least in part by the increased production of nitric oxide. The vulnerability of immunostimulated C6 glioma cells to hypoglycemic insults may implicate that the elevated level of cytokines in various ischemic and neurodegenerative diseases may play a role in their pathogenesis.

• Asian Pacific Journal of Cancer Prevention
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• 제15권19호
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• pp.8405-8408
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• 2014

Background: This analysis was conducted to evaluate the efficacy and safety of temozolomide based chemotherapy in treating patients with glioma. Methods: Clinical studies evaluating the efficacy and safety of temozolomide based regimens for patients with glioma were identified using a predefined search strategy. Pooled response rates (RRs) were calculated. Results: In temozolomide based regimens, 5 clinical studies including 152 patients with advanced glioma were considered eligible for inclusion. Four clinical studies included temozolomide. Systematic analysis suggested that, in all patients, pooled CR was 21% (32/152), and PR was 21% (32/152). Grade 3/4 toxicity included neutropenia, thrombocytopenia, and anemia. No grade 3 or 4 renal or liver toxicity was observed. No treatment related death occurred with temozolomide based treatment. Conclusion: This systematic analysis suggests that temozolomide based regimens are associated with mild response rate and acceptable toxicity for treatment of glioma patients.

• 대한의생명과학회지
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• 제12권3호
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• pp.261-265
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• 2006

Toxic effect of Hexavalent chromium $(CrO_3)$ on various cells and organs has been well recognized. However, the mechanism and degree of cytotoxicity of $CrO_3$ remain unclear. This study was performed to examine the cytotoxicity of $CrO_3$ on $C_6$ glioma cells by measuring cell viability. The XTT assay, one of the sensitive methods to determine the cell viability, was taken to examine the viability of glioma cells treated with $CrO_3$. In this study, not only decreased the number of glioma cells but morphologic changes of them were noted and cell viability decreased in a time and dose-dependent manner after treated with various concentrations of $CrO_3$ for 48hours. $IC_{90}\;and\;IC_{50}$ values in XTT assay were determined at $25{\mu}M\;and\;55{\mu}M$ $CrO_3$, respectively. These results suggest that Hexavalent chromium has a highly cytotoxic effect and has a time and dose-dependent cytotoxicity on $C_6$ glioma cells.

• International Journal of Computer Science & Network Security
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• 제21권2호
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• pp.198-204
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• 2021

Glioma is one of the common types of brain tumors starting in the brain's glial cell. These tumors are classified into low-grade or high-grade tumors. Physicians analyze the stages of brain tumors and suggest treatment to the patient. The status of the tumor has an importance in the treatment. Nowadays, computerized systems are used to analyze and classify brain tumors. The accurate grading of the tumor makes sense in the treatment of brain tumors. This paper aims to develop a classification of low-grade glioma and high-grade glioma using a deep learning algorithm. This system utilizes four transfer learning algorithms, i.e., AlexNet, GoogLeNet, ResNet18, and ResNet50, for classification purposes. Among these algorithms, ResNet18 shows the highest classification accuracy of 97.19%.

• Asian Pacific Journal of Cancer Prevention
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• 제13권11호
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• pp.5725-5728
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• 2012

Growing evidence shows that deregulation of the circadian clock plays an important role in the development of malignant tumors, including gliomas. However, the molecular mechanisms of gene chnages controlling circadian rhythm in glioma cells have not been explored. Using real time polymerase chain reaction and immunohistochemistry techniques, we examined the expression of two important clock genes, cry1 and cry2, in 69 gliomas. In this study, out of 69 gliomas, 38 were cry1-positive, and 51 were cry2-positive. The expression levels of cry1 and cry2 in glioma cells were significantly different from the surrounding non-glioma cells (P<0.01). The difference in the expression rate of cry1 and cry 2 in high-grade (grade III and IV) and low-grade (grade 1 and II) gliomas was non-significant (P>0.05) but there was a difference in the intensity of immunoactivity for cry 2 between high-grade gliomas and low-grade gliomas (r=-0.384, P=0.021). In this study, we found that the expression of cry1 and cry2 in glioma cells was much lower than in the surrounding non-glioma cells. Therefore, we suggest that disturbances in cry1 and cry2 expression may result in the disruption of the control of normal circadian rhythm, thus benefiting the survival of glioma cells. Differential expression of circadian clock genes in glioma and non-glioma cells may provide a molecular basis for the chemotherapy of gliomas.

• Asian Pacific Journal of Cancer Prevention
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• 제15권19호
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• pp.8107-8113
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• 2014

The aim of this study was to investigate the effects of olanzapine on growth inhibition as well as autophagy in glioma cells in vitro and in vivo. The proliferation of both LN229 and T98 glioma cells, measured by MTT assay, was suppressed in a concentration-dependent and time-dependent manner. Moreover, apoptosis of both cells was significantly increased with the treatment of olanzapine as evidenced by increased Bcl-2 expression, Hoechst 33258 staining and annexinV-FITC/PI staining. Olanzapine treatment also enhanced activation of autophagy with increased expression of LC3-II, expression of protein p62, a substrate of autophagy, being decreased. The growth inhibition by olanzapine in both glioma cell lines could be blocked by co-treatment with 3-MA, an autophagy inhibitor. Furthermore, olanzapine effectively blocked the growth of subcutaneous xenografts of LN229 glioma cells in vivo. The increased level of protein LC3-II and decreased level of p62 followed by a decreased level of Bcl-2, suggesting that autophagy may contribute to apoptosis. In addition, reduced proliferation of glioma cells was shown by a decrease of Ki-67 staining and increased caspase-3 staining indicative of apoptosis in mouse xenografts. These results indicated that olanzapine inhibited the growth of glioma cells accompanied by induction of autophagy and apoptosis both in vitro and in vivo. Olanzapine-induced autophagy plays a tumor-suppressing role in glioma cells.

• 생명과학회지
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• 제26권4호
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• pp.490-495
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• 2016

Brefeldin A (BFA)는 Eupenicillium brefeldianum에서 분리한 lactone계열의 항생제이며 ER에서 Golgi로 단백질 이송/전달을 억제히는 기능이 있다. 따라서 BFA를 세포에 처리 시 Golgi 기능 장애와 ER에서 단백질의 폴딩/조립의 문제로 인하여 ER에 기능 장애가 발생하는데 이를 소포체 스트레스(ER stress)라고 한다. 본 연구에서는 정상 astrocyte 세포와 C6 glioma 세포에서의 BFA처리에 따라 ER stress marker 단백질인 CHOP 발현 차이를 확인하였다. BFA 처리 시 CHOP 발현이 정상 astrocyte 세포에서 C6 glioma 세포에 비해 현저히 낮은 발현을 확인하였다. 하지만 CHOP mRNA 발현에서는 astrocyte 세포에서 발현 됨을 RT-PCR로 확인하였다. C6 glioma 세포와 비교하여 astrocyte 세포에서 BFA유도의 CHOP 단백질 발현이 낮은 원인은 proteasome 활성이 높음으로 기인됨을 proteasome inhibitor 실험과 proteasome 활성 측정을 통하여 확인하였다.

• Asian Pacific Journal of Cancer Prevention
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• 제15권23호
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• pp.10175-10179
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• 2015

Background: The association between the RTEL1 rs6010620 single nucleotide polymorphism (SNP) and glioma risk has been extensively studied. However, the results remain inconclusive. To further examine this association, we performed a meta-analysis. Materials and Methods: A computerized search of the PubMed and Embase databases for publications regarding the RTEL1 rs6010620 polymorphism and glioma cancer risk was performed. Genotype data were analyzed in a meta-analysis. Odds ratios (ORs) with 95% confidence intervals (CIs) were estimated to assess the association. Sensitivity analyses, tests of heterogeneity, cumulative meta-analyses, and assessments of bias were performed in our meta-analysis. Results: Our meta-analysis confirmed that risk with allele A is lower than with allele G for glioma. The A allele of rs6010620 in RTEL1 decreased the risk of developing glioma in the 12 case-control studies for all genetic models: the allele model (OR=0.752, 95%CI: 0.715-0.792), the dominant model (OR=0.729, 95%CI: 0.685-0.776), the recessive model (OR=0.647, 95%CI: 0.569-0.734), the homozygote comparison (OR=0.528, 95%CI: 0.456-0.612), and the heterozygote comparison (OR=0.761, 95%CI: 0.713-0.812). Conclusions: In all genetic models, the association between the RTEL1 rs6010620 polymorphism and glioma risk was significant. This meta-analysis suggests that the RTEL1 rs6010620 polymorphism may be a risk factor for glioma. Further functional studies evaluating this polymorphism and glioma risk are warranted.

• Asian Pacific Journal of Cancer Prevention
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• 제16권2호
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• pp.769-773
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• 2015

Fibulin-5 has recently been considered as a potential tumor suppressor in human cancers. Several studies have shown that it is down-regulated in a variety of tumor types and inhibits tumor growth and metastasis. This study was aimed to investigate the clinical significance of fibulin-5 in glioma and its role in cell proliferation and invasion. We found that the expression of fibulin-5 in glioma tissues was significantly lower than those in normal brain (NB) tissues. Negative expression was significantly correlated with advanced clinical stage (grade III+IV). Furthermore, Fibulin-5 negative expression was correlated with a shorter overall survival of glioma patients. Multivariate Cox repression analysis indicated that fibulin-5 was an independent factor for predicting overall survival of glioma patients. Overexpression obviously inhibited cell proliferation in U251 and U87 cells. Furthermore, it significantly reduced the number of migrating and invading glioma cells. In conclusion, impaired expression of fibulin-5 is correlated with the advanced tumor stage in glioma. Otherwise, Fibulin-5 is an independent prognostic marker for predicting overall survival of glioma patients. Mechanistically, it may function as a tumor suppressor via inhibiting cell proliferation and invasion in gliomas.

• Asian Pacific Journal of Cancer Prevention
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• 제14권7호
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• pp.4083-4087
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• 2013

We conducted an exploratory investigation of whether variation in six common SNPs of xeroderma pigmentosum complementation group F (XPF) is associated with risk of glioma in a Chinese population. Six single nucleotide polymorphisms (SNPs) were genotyped in 207 glioma cases and 236 cancer-free controls by a 384-well plate format on the Sequenom MassARRAY platform (Sequenom, San Diego, USA). The rs1800067 G and rs2276466 G allele frequencies were significantly higher in the glioma group than controls. Individuals with the rs1800067 GG genotype were at greater risk of glioma when compared with the A/A genotype in the codominant model, with an OR (95% CI) of 2.63 (1.04-7.25). The rs2276466 polymorphism was significantly associated with moderate increased risk of glioma in codominant and dominant models, with ORs (95% CI) of 1.90 (1.05-3.44) and 1.55 (1.07-2.47), respectively. The combination genotype of rs1800067 G and rs2276466 G alleles was associated with a reduced risk of glioma (OR=0.44, 95% CI=0.19-0.98). These findings indicate that genetic variants of the XPF gene have critical functions in the development of glioma.