• 대한약학회:학술대회논문집
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• 대한약학회 2003년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2-2
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• pp.148.1-148.1
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• 2003

Ceramide is an important lipid messenger involved in mediating a variety of cell functions including apoptosis. Previously, we have shown that ceramide induces Bax translocation which is associated with cytochrome c release from the mitochondria. In this study, we show that p38 MAP kinase is involved in ceramide-induced Bax translocation. In human leukemic cells, ceramide stimulated the phosphorylation of p38 MAP kinase. Preincubation of cells with SB203580, a specific inhibitor of p38 inhibited DNA fragmentation induced by cell-permeable ceramide. (omitted)

• 대한약학회:학술대회논문집
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• 대한약학회 2002년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2
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• pp.338.2-338.2
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• 2002

Ceramide is a lipid second messenger that is involved in apoptotic cell death. In this study, we show that p38 MAPK plays an important role in the regulation of ceramide-induced apoptosis. We found that SB203580, a p38 kinase inhibitor, blocked the effects of ceramide to induce Bax translocation to mitochondria, activation of caspase-3, and DNA fragmentation. Furthermore. expression of a dominant negative form of p38 MAPK suppressed ceramide-induced Bax translocation, suggesting that p38 kinase activity is essential for Bax translocation. (omitted)

• Animal Bioscience
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• 제37권3호
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• pp.471-480
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• 2024

Objective: The objective of this study was to investigate the regulation relationship of Ten-eleven translocation 1 (Tet1) in DNA demethylation and the proliferation of primordial germ cells (PGCs) in chickens. Methods: siRNA targeting Tet1 was used to transiently knockdown the expression of Tet1 in chicken PGCs, and the genomic DNA methylation status was measured. The proliferation of chicken PGCs was detected by flow cytometry analysis and cell counting kit-8 assay when activation or inhibition of Wnt4/β-catenin signaling pathway. And the level of DNA methylation and hisotne methylation was also tested. Results: Results revealed that knockdown of Tet1 inhibited the proliferation of chicken PGCs and downregulated the mRNA expression of Cyclin D1 and cyclin-dependent kinase 6 (CDK6), as well as pluripotency-associated genes (Nanog, PouV, and Sox2). Flow cytometry analysis confirmed that the population of PGCs in Tet1 knockdown group displayed a significant decrease in the proportion of S and G2 phase cells, which meant that there were less PGCs entered the mitosis process than that of control. Furthermore, Tet1 knockdown delayed the entrance to G1/S phase and this inhibition was rescued by treated with BIO. Consistent with these findings, Wnt/β-catenin signaling was inactivated in Tet1 knockdown PGCs, leading to aberrant proliferation. Further analysis showed that the methylation of the whole genome increased significantly after Tet1 downregulation, while hydroxyl-methylation obviously declined. Meanwhile, the level of H3K27me3 was upregulated and H3K9me2 was downregulated in Tet1 knockdown PGCs, which was achieved by regulating Wnt/β-catenin signaling pathway. Conclusion: These results suggested that the self-renewal of chicken PGCs and the maintenance of their characteristics were regulated by Tet1 mediating DNA demethylation through the activation of Wnt4/β-catenin signaling pathway.

• 센서학회지
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• 제21권5호
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• pp.359-366
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• 2012

Nanopore DNA sequencing is an emerging and promising technique that can potentially realize the goal of a low-cost and high-throughput method for analyzing human genome. Especially, solid-state nanopores have relatively high mechanical stability, simple surface modification, and facile fabrication process without the need for labeling or amplification of PCR (polymerized chain reaction) in DNA sequencing. For these advantages of solid-sate nanopores, the use of solid-state nanopores has been extensively considered for developing a next generation DNA sequencing technology. Solid-state nanopore sequencing technique can determine and count charged molecules such as single-stranded DNA, double-stranded DNA, or RNA when they are driven to pass through a membrane nanopore between two electrolytes of cis-trans chambers with applied bias voltage by measuring the ionic current which varies due to the existence of the charged particles in the nanopore. Recently, many researchers have suggested that nanopore-based sensors can be competitive with other third-generation DNA sequencing technologies, and may be able to rapidly and reliably sequence the human genome for under $1,000.

• International Journal of Oral Biology
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• 제39권3호
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• pp.159-167
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• 2014

Curcumin is a widely used flavoring agent in food, and it has been reported to inhibit cell growth, to induce apoptosis, and to have antitumor activity in many cancers. Cisplatin is one of the most potent known anticancer agents and shows significant clinical activity against a variety of solid tumors. This study was undertaken to investigate the synergistic apoptotic effects of co-treatment with curcumin and cisplatin on human tongue SCC25 cells. To investigate whether the co-treatment efficiently reduced the viability of the SCC25 cells compared with the two treatments separately, an MTT assay was conducted. The induction and the augmentation of apoptosis were confirmed by DNA electrophoresis, Hoechst staining, and an analysis of DNA hypoploidy. Western blot, MMP and immunofluorescence tests were also performed to evaluate the expression levels and the translocation of apoptosis-related proteins following the co-treatment. In this study, following the co-treatment with curcumin and cisplatin, the SCC25 cells showed several forms of apoptotic manifestation, such as nuclear condensation, DNA fragmentation, reduction of MMP, increased levels of Bax, decreased levels of Bcl-2, and decreased DNA content. In addition, they showed a release of cytochrome c into the cytosol, translocation of AIF and DFF40 (CAD) to the nuclei, and activation of caspase-7, caspase-3, PARP, and DFF45 (ICAD). In contrast, separate treatments of $5{\mu}M$ of curcumin or $4{\mu}g/ml$ of cisplatin, for 24 hours, did not induce apoptosis. Therefore, our data suggest that combination therapy with curcumin and cisplatin could be considered as a novel therapeutic strategy for human oral squamous cell carcinoma.

• International Journal of Oral Biology
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• 제36권3호
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• pp.155-162
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• 2011

Eugenol (4-allyl-2-methoxyphenol) is a naturally occurring phenolic compound that is widely used in dentistry as a component of zinc oxide eugenol cement that is commonly applied to the mouth environment. Cisplatin is one of the most potent known anticancer agents and shows significant clinical activity against a variety of solid tumors. This study was undertaken to investigate the synergistic apoptotic effects of co-treatments with eugenol and cisplatin on human melanoma (G361) cells. To investigate whether this co-treatment efficiently reduces the viability of G361 cells compared with each single treatment, an MTT assay was conducted. The induction and augmentation of apoptosis were confirmed by DNA electrophoresis, Hoechst staining and an analysis of DNA hypoploidy. Western blot analysis and immunofluorescent staining were also performed to evaluate the expression levels and the translocation of apoptosis-related proteins following this co-treatment. Furthermore, proteasome activity and mitochondrial membrane potential (MMP) changes were also assayed. The results indicated that a co-treatment with eugenol and cisplatin induced multiple pathways and processes associated with an apoptotic response in G361 cells including nuclear condensation, DNA fragmentation, a reduction in MMP and proteasome activity, the increase and decrease of Bax and Bcl-2, a decreased DNA content, the release of cytochrome c into the cytosol, the translocation of AIF and DFF40 (CAD) into the nucleus, and the activation of caspase-9, caspase-7, caspase-3, PARP and DFF45 (ICAD). In contrast, separate treatments of 300 ${\mu}M$ eugenol or 3 ${\mu}M$ cisplatin for 24 h did not induce apoptosis. Our present data thus suggest that a combination therapy of eugenol and cisplatin is a potential treatment strategy for human melanoma.

• International Journal of Oral Biology
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• 제38권3호
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• pp.101-110
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• 2013

We investigated the synergistic apoptotic effects of co-treatments with Chios gum mastic (CGM) and eugenol on G361 human melanoma cells. An MTT assay was conducted to investigate whether this co-treatment efficiently reduces the viability of G361 cells compared with each single treatment. The induction and augmentation of apoptosis were confirmed by DNA electrophoresis, Hoechst staining, and analyses of DNA hypoploidy. Western blot analysis and immunofluorescent staining were also performed to evaluate expression and translocation of apoptosis-related proteins following CGM and eugenol co-treatment. Proteasome activity and mitochondrial membrane potential (MMP) changes were also assayed.The results indicated that the co-treatment of CGM and eugenol induces multiple pathways and processes associated with an apoptotic response in G361 cells. These include nuclear condensation, DNA fragmentation, a reduction in MMP and proteasome activity, an increase of Bax and decrease of Bcl-2, a decreased DNA content, cytochrome c release into the cytosol, the translocation of AIF and DFF40 (CAD) into the nucleus, and the activation of caspase-9, caspase-7, caspase-3, PARP and DFF45 (ICAD). In contrast, separate treatments of $40{\mu}g/ml$ CGM or $300{\mu}M$ eugenol for 24 hours did not induce apoptosis. Our present data thus suggest that a combination therapy of CGM and eugenol is a potential treatment strategy for human melanoma.

• Molecules and Cells
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• 제22권2호
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• pp.203-209
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• 2006

TBP (TATA-binding protein)-related factor 2 (TRF2) regulates transcription during a nuber of cellular processes. We previously demonstrated that it is localized in the cytoplasm and is translocated to the nucleus by DNA-damaging agents. However, the cytoplasmic localization of TRF2 is controversial. In this study, we reconfirmed its cytoplasmic localization in various ways and examined its nuclear migration. Stresses such as heat shock, redox agents, heavy metals, and osmotic shock did not affect localization whereas genotoxins such as methyl methanesulfonate (MMS), cisplatin, etoposide, and hydroxyurea caused it to migrate to the nucleus. Adriamycin, mitomycin C and ${\gamma}$-rays had no obvious effect. We determined optimal conditions for the nuclear migration. The proportions of cells with nuclei enriched for TRF2 were 25-60% and 5-10% for stressed cells and control cells, respectively. Nuclear translocation was observed after 1 h, 4 h and 12 h for cisplatin, etoposide and MMS and hydroxyurea, respectively. The association of TRF2 with the chromatin and promoter region of the proliferating cell nuclear antigen (PCNA) gene, a putative target of TRF2, was increased by MMS treatment. Thus TRF2 may be involved in genotoxin-induced transcriptional regulation.

• Journal of Periodontal and Implant Science
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• 제41권3호
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• pp.157-163
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• 2011

Purpose: Curcumin is known to exert numerous biological effects including anti-inflammatory activity. In this study, we investigated the effects of curcumin on the production of interleukin-6 (IL-6) by murine macrophage-like RAW 264.7 cells stimulated with lipopolysaccharide (LPS) from Prevotella intermedia, a major cause of inflammatory periodontal disease, and sought to determine the underlying mechanisms of action. Methods: LPS was prepared from lyophilized P. intermedia ATCC 25611 cells by the standard hot phenol-water method. Culture supernatants were collected and assayed for IL-6. We used real-time polymerase chain reaction to detect IL-6 mRNA expression. $I{\kappa}B-{\alpha}$ degradation, nuclear translocation of NF-${\kappa}B$ subunits, and STAT1 phosphorylation were characterized via immunoblotting. DNA-binding of NF-${\kappa}B$ was also analyzed. Results: Curcumin strongly suppressed the production of IL-6 at both gene transcription and translation levels in P. intermedia LPS-activated RAW 264.7 cells. Curcumin did not inhibit the degradation of $I{\kappa}B-{\alpha}$ induced by P. intermedia LPS. Curcumin blocked NF-${\kappa}B$ signaling through the inhibition of nuclear translocation of NF-${\kappa}B$ p50 subunit. Curcumin also attenuated DNA binding activity of p50 and p65 subunits and suppressed STAT1 phosphorylation. Conclusions: Although further study is required to explore the detailed mechanism of action, curcumin may contribute to blockade of the host-destructive processes mediated by IL-6 and appears to have potential therapeutic values in the treatment of inflammatory periodontal disease.

• Biomolecules & Therapeutics
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• 제24권3호
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• pp.268-282
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• 2016

In the present study, we investigated the anti-inflammatory properties of Eucommia ulmoides Oliv. Bark. (EUE) in lipopolysaccharide (LPS)-stimulated microglial BV-2 cells and found that EUE inhibited LPS-mediated up-regulation of pro-inflammatory response factors. In addition, EUE inhibited the elevated production of pro-inflammatory cytokines, mediators, and reactive oxygen species (ROS) in LPS-stimulated BV-2 microglial cells. Subsequent mechanistic studies revealed that EUE suppressed LPS-induced phosphorylation of mitogen-activated protein kinases (MAPKs), phosphoinositide-3-kinase (PI3K)/Akt, glycogen synthase $kinase-3{\beta}$ ($GSK-3{\beta}$), and their downstream transcription factor, nuclear factor-kappa B ($NF-{\kappa}B$). EUE also blocked the nuclear translocation of $NF-{\kappa}B$ and inhibited its binding to DNA. We next demonstrated that EUE induced the nuclear translocation of nuclear factor erythroid 2-related factor 2 (Nrf2) and upregulated heme oxygenase-1 (HO-1) expression. We determined that the significant up-regulation of HO-1 expression by EUE was a consequence of Nrf2 nuclear translocation; furthermore, EUE increased the DNA binding of Nrf2. In contrast, zinc protoporphyrin (ZnPP), a specific HO-1 inhibitor, blocked the ability of EUE to inhibit NO and $PGE_2$ production, indicating the vital role of HO-1. Overall, our results indicate that EUE inhibits pro-inflammatory responses by modulating MAPKs, PI3K/Akt, and $GSK-3{\beta}$, consequently suppressing $NF-{\kappa}B$ activation and inducing Nrf2-dependent HO-1 activation.