• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.11a
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• pp.162-165
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• 2000

To investigate the effect of metal electrode in electroluminescent[EL] devices, we fabricated EL devices of ITO/P3HT/Al, ITO/P3HT/LiF/Al and ITO/P3HT/Mg:In structure. In current-voltage-light power characteristics, turn-on voltage of EL devices using LiF insulating layer and Mg:In(2.8V) metal electrode is lower than EL device using Al(4.2V). Besides the external quantum efficiency is improved also. The reason is related to carrier mobility and carrier injection, which would affect the hole-electron balance. In the device with Al electrode, holes injected from indium-tin-oxide[ITO] to poly(3-hexylthiophene)[P3HT] might reach the Al electrode without interacting with injected electrons, because the electron injection efficiency was very low for this electrode. Besides oxidation of the Al electrode is likely due to holes reaching the cathode without meeting injected electrons. Another possible reason for the higher EL efficiency may be the insulating layer playing the role of a tunneling barrier for holes to the Al electrode. In all EL devices, the orange-red light was clearly visible in a dark room. Maximum peak wavelength of EL spectrum emitted at 640nm in accordance with photon energy 1.9eV

• The Korean Journal of Food And Nutrition
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• v.35 no.5
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• pp.359-368
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• 2022

In this study, the quality characteristics of kimchi, such as its salinity, pH, and acidity, were measured and compared, and the HT-29 human colon cancer cells were used to show the anticancer effects of kimchi. The kimchi samples used herein included standard kimchi (SK), turnip kimchi (TK), and turnip-powder-added kimchi (TPK). The measured pH and acidity of TK and TPK showed no significant differences with those of SK. Compared to SK and TK, TPK had higher DPPH scavenging activity and higher total flavonoid content, confirming its antioxidant activity. The cancer cell growth inhibition rates of TK and TPK were significantly higher than that of SK. In HT-29 cells treated with TPK, the mRNA expression of Bcl-xL, an anti-apoptosis-related gene, was lower, and the mRNA expressions of the apoptosis-related genes Bax, Bad, and caspase-9 were higher. TPK showed significantly higher levels of mRNA expressions for the cell-cycle-related genes p53 and p21 than the other samples, in addition to suppression effects on cancer cell proliferation. Compared to SK, TK and TPK suppressed the growth of colon cancer cells and showed higher anticancer effects. Therefore, it is shown that kimchi with added turnip powder had high anticancer effects.

• Proceedings of the Korean Nuclear Society Conference
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• 2005.05a
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• pp.433-434
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• 2005

• Molecules and Cells
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• v.38 no.2
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• pp.151-155
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• 2015

Matrix metalloproteinase (MMP)-9 degrades type IV collagen in the basement membrane and plays crucial roles in several pathological implications, including tumorigenesis and inflammation. In this study, we analyzed the effect of flavonols on MMP-9 expression in phorbol-12-myristate-13-acetate (PMA)-induced human fibrosarcoma HT-1080 cells. Galangin and kaempferol efficiently decreased MMP-9 secretion, whereas fisetin only weakly decreased its secretion. Galangin and kaempferol did not affect cell viability at concentrations up to $30{\mu}M$. Luciferase reporter assays showed that galangin and kaempferol decrease transcription of MMP-9 mRNA. Moreover, galangin and kaempferol strongly reduce $I{\kappa}B{\alpha}$ phosphorylation and significantly decrease JNK phosphorylation. These results indicate that galangin and kaempferol suppress PMA-induced MMP-9 expression by blocking activation of NF-${\kappa}B$ and AP-1. Therefore, these flavonols could be used as chemopreventive agents to lower the risk of diseases involving MMP-9.

• THE JOURNAL OF KOREAN ORIENTAL ONCOLOGY
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• v.4 no.1
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• pp.131-146
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• 1998

To examine the effect of Shiquandabutang on the metastasis of cancer, the following experiments were made. Before the main experiments, the cytotoxicity was measured by putting Shiquandabutang sample in HT1080. Then zymography was made to examine the change of gelatinolytic activity. And western blotting was carried out to examine the changes of Fos, Jun, Ets, the transcription factors of MMP-2, MMP-9, and Erk, JNK on signal transduction pathway to AP-1. Third, in vitro invasion assay with transwells coated by collagen and matrigel was carried out. From the results of the above the following conclusions were obtained. 1. The experimental result about cytotoxicity of Shiquandabutang against HT1080 was as below. The stained cell count after being treated by Shiquandabutang sample $400{\mu}g/ml$ for 24 hours was 0.9% of total cells, and the stained cell count by Shiquandabutang sample $100{\mu}g/ml$ was 1.5% of total cells. Both were near the level of control group which showed 0.6% stained. 2. The result of collagenase assay was as below. In Shiquandabutang sample $400{\mu}g/ml$, MMP-2 was reduced as compared with TPA control group, and the band of MMP-9 induced by TPA disappeared. In Shiquandabutang sample $800{\mu}g/ml$, both bands of MMP-2 and MMP-9 disappeared. 3. The results of western blots for Jun, Fos, Ets, Erk, JNK were as below. In Shiquandabutang sample $200{\mu}g/ml$, Ets was reduced, and Fos were increased. 4. The result of invasion assay was as below. The number of cells which migrated across transwell membrane in Shiquandabutang-treated group was less than that of +TPA control group. From the above results, it was concluded that Shiquandabutang might control the appearing and acting of collagenase not by the MMP-2, -9 promoter but by other way.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.4
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• pp.431-438
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• 2007

In the present study, twenty eight marine algae species were evaluated for their antiproliferative effect on HT-29 human colon cancer cells. Among these, the methanolic extract of Symphyocladia latiuscula (SL Ex) showed the highest inhibitory activity on HT-29 cell growth. In this study, we examined the mechanism by which SL Ex inhibited the HT-29 cell growth. Cells were cultured with various concentrations of $(0{\sim}20{\mu}g/mL)$ SL Ex. The SL Ex substantially decreased the viable cell numbers and induced apoptosis of HT-29 cells in a dose-dependent manner Western blot analyses of total cell lysates revealed that SL Ex increased the levels of cleaved caspase-8, -9, -7, and -3, and poly (ADP-ribose) polymerase in HT-29 cells. In addition, SL Ex increased truncated Bid levels but moderately decreased Bax levels at only $20{\mu}g/mL$. Furthermore, SL Ex did not affect Bcl-2 protein levels but increased the levels of Fas in HT-29 cells. The present results indicate that SL Ex inhibits cell growth via inducing apoptosis in human colon cancer cells. The mechanism of apoptosis induction by SL Ex involves caspase-8 activation leading to changes in mitochondrial events and subsequent activation of the caspase-7/caspase-3 cascade. Our finding may lead to the development of new therapeutic strategies for the treatment of colon cancer.

• Korean Journal of Food Science and Technology
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• v.40 no.2
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• pp.207-214
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• 2008

In Asia Saussurea lappa (SL) has been used as a traditional herbal medicine to treat abdominal pain and tenesmus. Recently, in vitro cell culture studies have shown that SL has anti-ulcer, anti-inflammatory, and anti-tumor properties. To explore its potential chemopreventive and chemotherapeutic effects in colon cancer, we examined whether the hexane extract of SL (HESL) could inhibit the growth of HT-29 human colon cancer cells, and investigated the mechanisms for this effect. The cells were cultured with various concentrations (0-5 ${\mu}g/mL$) of HESL. The results indicated that HESL markedly decreased the numbers of viable HT-29 cells; whereas at the concentration of 5 ${\mu}g/mL$, HESL slightly decreased the viable cell numbers of CCD 1108Sk human skin normal fibroblasts at 72 hr. HESL substantially increased the numbers of cells in the sub G1 phase, and dose-dependently increased apoptotic cell numbers. Western blot analysis of the total cell lysates revealed that HESL increased Bax protein levels, but did not affect Bcl-2 levels. HESL induced the cleavage of poly (ADP-ribose) polymerase and caspases 8, 9, 7, and 3. This study demonstrated that HESL inhibits cell growth and induces apoptosis in HT-29 cells, which may be mediated by its ability to increase Bax levels and activate the caspase pathway. These findings may lead to the development of new therapeutic strategies for colon cancer treatment.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.9
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• pp.4751-4756
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• 2012

Colon cancer continues to be one of the most common cancers, and the importance and necessity of new therapies needs to be stressed. The most important proto-oncogen factors for colon cancer appear to be epidermal growth factor receptor, EGFR, and c-Src with high expression and activity leading to tumor growth and ultimately to colon cancer progression. Application of c-Src and EGFR antisense agents simultaneously should theoretically therefore have major benefit. In the present study, anti-EGFR and c-Src specific antisense oligodeoxynucleotides were combined in a formulation using PAMAM dendrimers as a carrier. Nano drug entry into cells was confirmed by flow cytometry and fluorescence microscopy imaging and real time PCR showed gene expression of c-Src and EGFR, as well as downstream STAT5 and MAPK-1 with the tumor suppressor gene P53 to all be downregulated. EGFR and c-Src protein expression was also reduced when assessed by western blotting techniques. The effect of the antisense oligonucleotide on HT29 cell proliferation was determined by MTT assay, reduction beijng observed after 48 hours. In summary, nano-drug, anti-EGFR and c-Src specific antisense oligodeoxynucleotides were effectively transferred into HT-29 cells and inhibited gene expression in target cells. Based on the results of this study it appears that the use of antisense EGFR and c-Src simultaneously might have a significant effect on colon cancer growth by down regulation of EGFR and its downstream genes.

• Journal of Korean Traditional Oncology
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• v.11 no.1
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• pp.55-63
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• 2006

This study was conducted to investigate angiogenic inhibitory effect of Zingiberis Rhizoma methanol extract using ECV-304 cells and HT1080 fibrosarcoma cells. The viability of ECV-304 was 30% at 50${\mu}g/m{\ell}$ of Zingiberis extract and that of HT1080 was 30% at 100${\mu}g/m{\ell}$. Using the BrdU incorporation assay, Zingiberis inhibited the DNA synthesis of ECV-304 and HT1080 by 70% and 50 % at 200${\mu}g/m{\ell}$. In tube formation assay, at 10${\mu}g/m{\ell}$ of Zingiberis, tube network began to degrade and at higher doses, it was completely destroyed. Zymography demonstrated that Zingiberis extract decreased MMP-9 at 10${\mu}g/m{\ell}$ and higher doses remarkably inhibited the expression of MMP-9. These data indicate that Zingiberis Rhizoma has angiogenic inhibitory effects and shows the possibility of future anti-metastatic drug.

• Nutrition Research and Practice
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• v.9 no.2
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• pp.111-116
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• 2015

BACKGROUND/OBJECTIVES: Inonotus obliquus (I. obliquus, Chaga mushroom) has long been used as a folk medicine to treat cancer. In the present study, we examined whether or not ethanol extract of I. obliquus (EEIO) inhibits cell cycle progression in HT-29 human colon cancer cells, in addition to its mechanism of action. MATERIALS/METHODS: To examine the effects of Inonotus obliquus on the cell cycle progression and the molecular mechanism in colon cancer cells, HT-29 human colon cancer cells were cultured in the presence of $2.5-10{\mu}g/mL$ of EEIO, and analyzed the cell cycle arrest by flow cytometry and the cell cycle controlling protein expression by Western blotting. RESULTS: Treatment cells with $2.5-10{\mu}g/mL$ of EEIO reduced viable HT-29 cell numbers and DNA synthesis, increased the percentage of cells in $G_1$ phase, decreased protein expression of CDK2, CDK4, and cyclin D1, increased expression of p21, p27, and p53, and inhibited phosphorylation of Rb and E2F1 expression. Among I. obliquus fractions, fraction 2 (fractionated by dichloromethane from EEIO) showed the same effect as EEIO treatment on cell proliferation and cell cycle-related protein levels. CONCLUSIONS: These results demonstrate that fraction 2 is the major fraction that induces $G_1$ arrest and inhibits cell proliferation, suggesting I. obliquus could be used as a natural anti-cancer ingredient in the food and/or pharmaceutical industry.