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Search Results: 1 - 10 of 3532 matches for " Seung-Hae Kwon "
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Sensitive optical detection of an early metastatic tumor using a new cell line with enhanced luminescent and fluorescent signals
Yeon Joo Kim,Young Han Kim,Ok Kyu Park,Seung-Hae Kwon
Journal of Analytical Science & Technology , 2011,
Abstract: Animal models using cell lines that are dual-labeled with luciferase and green fluorescent protein (GFP) are powerful tools for performing simultaneous quantitative and qualitative analysis of metastatic tumors. However, the applications of such dual-labeled tumor models have been limited due to the technical challenges associated with low bioluminescent signaling from tumor cells. Here, we used lentiviral vector (LV) encoding firefly luciferase and GFP and engineered a more sensitive and highly metastatic prostate cancer cell line (MLL-Luc/GFP cells), which allows simultaneous fluorescence and luminescence imaging. The light emission of MLL-Luc/GFP cells was 33.5 fold higher than that of PC-3-luc2-GFP prostate cancer cells which showed 750 p/s light emission per cell. Furthermore, the MLL-Luc/GFP cells showed 3.9 fold higher luciferase activities than did 4T1-luc2, which was previously recognized as exhibiting the highest luciferase activity. An in vivo evaluation with optical imaging showed pinpoint localization of GFP-positive cells in a metastatic lung as well as easy detection of early metastatic spreading. The newly engineered MLL-Luc/GFP cells provide an appropriate metastatic animal model system for future studies of metastasis and the testing of anti-metastatic therapies specifically aimed at prostatic cancer.
TIMP-2 Fusion Protein with Human Serum Albumin Potentiates Anti-Angiogenesis-Mediated Inhibition of Tumor Growth by Suppressing MMP-2 Expression
Mi-Sook Lee, Jae-In Jung, Seung-Hae Kwon, Sang-Mok Lee, Kyoji Morita, Song Her
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0035710
Abstract: TIMP-2 protein has been intensively studied as a promising anticancer candidate agent, but the in vivo mechanism underlying its anticancer effect has not been clearly elucidated by previous works. In this study, we investigated the mechanism underlying the anti-tumor effects of a TIMP-2 fusion protein conjugated with human serum albumin (HSA/TIMP-2). Systemic administration of HSA/TIMP-2 effectively inhibited tumor growth at a minimum effective dose of 60 mg/kg. The suppressive effect of HSA/TIMP-2 was accompanied by a marked reduction of in vivo vascularization. The anti-angiogenic activity of HSA/TIMP-2 was directly confirmed by CAM assays. In HSA/TIMP-2-treated tumor tissues, MMP-2 expression was profoundly decreased without a change in MT1-MMP expression of PECAM-1-positive cells. MMP-2 mRNA was also decreased by HSA/TIMP-2 treatment of human umbilical vein endothelial cells. Zymographic analysis showed that HSA/TIMP-2 substantially decreased extracellular pro-MMP-2 activity (94–99% reduction) and moderately decreased active MMP-2 activity (10–24% reduction), suggesting MT1-MMP-independent MMP-2 modulation. Furthermore, HSA/TIMP-2 had no effect on in vitro active MMP-2 activity and in vivo MMP-2 activity. These studies show that HSA/TIMP-2 potentiates anti-angiogenic activity by modulating MMP-2 expression, but not MMP-2 activity, to subsequently suppress tumor growth, suggesting an important role for MMP-2 expression rather than MMP-2 activity in anti-angiogenesis.
Intracellular ATP Assay of Live Cells Using PTD-Conjugated Luciferase
Mi-Sook Lee,Wan-Soon Park,Young Han Kim,Won Gyeong Ahn,Seung-Hae Kwon,Song Her
Sensors , 2012, DOI: 10.3390/s121115628
Abstract: Luciferase is a sensitive, reliable biological sensor used for measuring ATP. However, its widespread application in drug discovery and toxicology studies has been limited due to unavoidable cell extraction processes, which cause inaccurate measurements of intracellular ATP and obstruct the application of homogenous high-throughput screening. Recently, we developed a protein transduction domain-conjugated luciferase (PTD-Luc) for measuring cellular uptake efficacy. In this study, we evaluated the applicability of PTD-Luc to an intracellular ATP assay of live cells. The predominant fluorescence of Alexa 647-PTD-Luc was in the cytosol, whereas the fluorescence of Alexa 647-Luc was visualized surrounding the cell membrane, as confirmed by Western blot analysis. In vitro, PTD-Luc could detect less than 10–9 M ATP, and the correlation between the luciferase activity of PTD-Luc and the ATP content was strong (R = 0.999, p < 0.001). In vivo, luminescence signals of PTD-Luc detected intracellular ATP in as few as 50 HeLa cells, with a strong correlation between luminescence and cell number, suggesting high sensitivity and reliability. Furthermore, two blockers of the glycolytic pathway (2-deoxyglucose and iodoacetic acid) inhibited the signal in a dose-dependent manner, whereas potassium cyanide, an inhibitor of oxidative phosphorylation, had no effect on intracellular ATP in vivo, as seen with the PTD-Luc sensor. These data show that PTD-Luc can directly measure the intracellular ATP content in live cells, allowing real-time kinetic studies, suggesting that it is a promising tool for high-throughput drug screening and cytotoxicity assays.
Bioinformatic Analysis of Nematode Migration-Associated Genes Identifies Novel Vertebrate Neural Crest Markers
Seung-Hae Kwon, Ok Kyu Park, Shuyi Nie, Jina Kwak, Byung Joon Hwang, Marianne E. Bronner, Yun Kee
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0103024
Abstract: Neural crest cells are highly motile, yet a limited number of genes governing neural crest migration have been identified by conventional studies. To test the hypothesis that cell migration genes are likely to be conserved over large evolutionary distances and from diverse tissues, we searched for vertebrate homologs of genes important for migration of various cell types in the invertebrate nematode and examined their expression during vertebrate neural crest cell migration. Our systematic analysis utilized a combination of comparative genomic scanning, functional pathway analysis and gene expression profiling to uncover previously unidentified genes expressed by premigratory, emigrating and/or migrating neural crest cells. The results demonstrate that similar gene sets are expressed in migratory cell types across distant animals and different germ layers. Bioinformatics analysis of these factors revealed relationships between these genes within signaling pathways that may be important during neural crest cell migration.
Neuroprotective Effect of a New Synthetic Aspirin-decursinol Adduct in Experimental Animal Models of Ischemic Stroke
Bing Chun Yan, Joon Ha Park, Bich Na Shin, Ji Hyeon Ahn, In Hye Kim, Jae-Chul Lee, Ki-Yeon Yoo, In Koo Hwang, Jung Hoon Choi, Jeong Ho Park, Yun Lyul Lee, Hong-Won Suh, Jong-Gab Jun, Young-Guen Kwon, Young-Myeong Kim, Seung-Hae Kwon, Song Her, Jin Su Kim, Byung-Hwa Hyun, Chul-Kyu Kim, Jun Hwi Cho, Choong Hyun Lee, Moo-Ho Won
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0074886
Abstract: Stroke is the second leading cause of death. Experimental animal models of cerebral ischemia are widely used for researching mechanisms of ischemic damage and developing new drugs for the prevention and treatment of stroke. The present study aimed to comparatively investigate neuroprotective effects of aspirin (ASA), decursinol (DA) and new synthetic aspirin-decursinol adduct (ASA-DA) against transient focal and global cerebral ischemic damage. We found that treatment with 20 mg/kg, not 10 mg/kg, ASA-DA protected against ischemia-induced neuronal death after transient focal and global ischemic damage, and its neuroprotective effect was much better than that of ASA or DA alone. In addition, 20 mg/kg ASA-DA treatment reduced the ischemia-induced gliosis and maintained antioxidants levels in the corresponding injury regions. In brief, ASA-DA, a new synthetic drug, dramatically protected neurons from ischemic damage, and neuroprotective effects of ASA-DA may be closely related to the attenuation of ischemia-induced gliosis and maintenance of antioxidants.
Polyol-Free Synthesis of Uniformly Dispersed Pt/Graphene Oxide Electrocatalyst by Sulfuric Acid Treatment
Tae Kyu Lee,Hyang Jin Park,Min Ki Kwon,Ju Hae Jung,Junbom Kim,Seung Hyun Hur
Journal of Nanomaterials , 2012, DOI: 10.1155/2012/418737
Abstract: Polyol-free synthesis of highly loaded Pt catalysts on sulfuric-acid-treated graphene oxide (SGO) was reported. Sulfuric acid treatment increased the surface hydroxyl groups on graphene oxide (GO), which contributed to the reduction of Pt precursors in the absence of external reducing agent. By adjusting pH during the Pt reduction, we can get uniformly dispersed 2.5?nm size Pt nanoparticles on GO surface even at 50?wt% Pt loading amount. Cyclic voltammetry showed that increased pH resulted in increased electrochemical surface area. 1. Introduction Polymer electrolyte membrane fuel cell (PEMFC) is regarded as one of the best candidates for the future energy sources as it can generate the electricity in a carbon-free way through the carbon dioxide free electrochemical reaction. Generally, only hydrogen and oxygen (or air) are used as the fuel gas and the oxidant gas, respectively. Moreover, the product generated during this reaction is only pure water, which will not cause any harms to the environment and also can be used as the essential ingredient for human and nature [1]. Nevertheless, its high cost impedes the commercialization. To reduce materials cost by improving the catalyst performance, robust catalytic supporting materials must be developed to achieve high dispersion, utilization, activity, and stability [2]. Recently, the majority of the catalyst support research has focused on the use of graphitic materials such as carbon nanotube and graphene [3–5]. Graphene is extensively studied due to its excellent properties such as a large theoretical specific surface area, high intrinsic mobility, high Young’s modulus and thermal conductivity, and its optical transmittance and good electrical conductivity [6–9]. There are several pathways to fabricate graphene nanosheets including chemical vapor deposition, mechanical exfoliation, and chemical exfoliation; among them chemical exfoliation is regarded as the most suitable one for fuel cell application due to its versatility of their surface modifications, unique defect behaviors, functional groups, and advantages associated with low cost and easy scale up [10]. The Pt catalyst for PEMFC can be prepared by impregnation, polyol, and colloidal method [11, 12]. Generally, wet impregnation followed by reduction by gaseous hydrogen atmosphere at high temperatures or the chemical reduction of the metal precursors using reducing agents can be used but achieving small particle size and uniform size distribution of Pt in this ways is very difficult especially at high Pt loading amount. Instead, the colloidal method
Heavy metal chemistry in soils received long-term application of organic wastes  [PDF]
Soon-Ik Kwon, Yeon-Ah Jang, Kye-Hoon Kim, Goo-Bok Jung, Min-Kyeong Kim, Hae Hwang, Mi-Jin Chae, Seung-Chang Hong, Kyu-Ho So, Sun-Gang Yun, Kwon-Rae Kim
Journal of Agricultural Chemistry and Environment (JACEN) , 2012, DOI: 10.4236/jacen.2012.11001
Abstract: This study was carried out to understand the long-term effect of organic waste treatment on the fate of heavy metals originated from the organic wastes, together with examination of changes in soil properties. For this, the soils received three different organic wastes (municipal sewage sludge, alcohol fermentation processing sludge, pig manure compost) in three different rates (12.5, 25, 50 ton/ha/yr) for 7 years (1994 - 2000) were used. To see the long-term effect, plant growth study and soil examination were conducted twice in 2000 and 2010, respectively. There was no additional treatment of organic wastes for post ten years after ceasing organic waste treatment for seven years. Soil examination conducted in 2010 showed decreases in soil pH, EC, total nitrogen, organic matter, available phosphorus, exchangeable cations and heavy metal contents in all soils received organic wastes compared to the results obtained in 2000. Speciation of heavy metals in soil through sequential extraction showed that organically bound Cu was the dominant species in all treatment and exchangeable Cu was increased in the plots treated with municipal sewage sludge and alcohol fermentation processing sludge. organically bound Ni increased from 25% - 30% to 32% - 45% in 2010 inall treatment while Pb showed increase in carbonate form in all treatments. Zn existed mainly as sulfide and residual forms, showing increases in organically bound form in all treatment during post ten years.

Tropomyosin3 overexpression and a potential link to epithelial-mesenchymal transition in human hepatocellular carcinoma
Hye-Sun Choi, Seon-Hee Yim, Hai-Dong Xu, Seung-Hyun Jung, Seung-Hun Shin, Hae-Jin Hu, Chan-Kwon Jung, Jong Choi, Yeun-Jun Chung
BMC Cancer , 2010, DOI: 10.1186/1471-2407-10-122
Abstract: TPM3-siRNA was transfected into 2 HCC cell lines, HepG2 and SNU-475, which had shown overexpression of TPM3. Knockdown of TPM3 was verified by real-time qRT-PCR and western blotting targeting TPM3. Migration and invasion potentials were examined using transwell membrane assays. Cell growth capacity was examined by colony formation and soft agar assays.Silencing TPM3 resulted in significant suppression of migration and invasion capacities in both HCC cell lines. To elucidate the mechanisms behind suppressed migration and invasiveness, we examined expression levels of Snail and E-cadherin known to be related to epithelial-mesenchymal transition (EMT) after TPM3 knockdown. In the TPM3 knockdown cells, E-cadherin expression was significantly upregulated and Snail downregulated compared with negative control. TPM3 knockdown also inhibited colony formation and anchorage independent growth of HCC cells.Based on our findings, we formulate a hypothesis that overexpression of TPM3 activates Snail mediated EMT, which will repress E-cadherin expression and that it confers migration or invasion potentials to HCC cells during hepatocarcinogenesis. To our knowledge, this is the first evidence that TPM3 gets involved in migration and invasion of HCCs by modifying EMT pathway.Hepatocellular carcinoma (HCC) is one of the most common human malignancies and the third leading cause of cancer-related death in the world [1]. A number of studies have been suggesting the molecular mechanisms involved in hepatocarcinogenesis such as MAPK, EGFR, p53, Wnt, TGF-B, Ras and Rb pathways [2-5]. However, given that prognosis of the disease remains poor, it is still important to understand hepatocarcinogenesis mechanisms and to identify effective markers for early diagnosis and accurate prognostication which reflect biological phenomena well.In our recent study which reported the chromosomal alterations in HCC by genome-wide array-CGH analysis, we found that a 1q21.3 locus was recurrently amplified a
Study design and rationale of 'Influence of Cilostazol-based triple anti-platelet therapy on ischemic complication after drug-eluting stent implantation (CILON-T)' study: A multicenter randomized trial evaluating the efficacy of Cilostazol on ischemic vascular complications after drug-eluting stent implantation for coronary heart disease
Seung-Pyo Lee, Jung-Won Suh, Kyung Woo Park, Hae-Young Lee, Hyun-Jae Kang, Bon-Kwon Koo, In-Ho Chae, Dong-Ju Choi, Seung-Woon Rha, Jang-Whan Bae, Myeong-Chan Cho, Taek-Geun Kwon, Jang-Ho Bae, Hyo-Soo Kim, CILON-T investigators
Trials , 2010, DOI: 10.1186/1745-6215-11-87
Abstract: CILON-T trial was a prospective, randomized, open-label, multi-center, near-all-comer trial to demonstrate the superiority of triple anti-platelet therapy to dual anti-platelet therapy in reducing 6 months' major adverse cardiovascular/cerebrovascular events, composite of cardiac death, nonfatal myocardial infarction, target lesion revascularization and ischemic stroke. It also tested whether triple anti-platelet therapy is superior to dual anti-platelet therapy in inhibiting platelet reactivity in patients receiving percutaneous coronary intervention with drug-eluting stent. Total 960 patients were randomized to receive either dual anti-platelet therapy or triple anti-platelet therapy for 6 months and also, randomly stratified to either lipophilic statin (atorvastatin) or non-lipophilic statin (rosuvastatin) indefinitely. Secondary endpoints included all components of major adverse cardiovascular/cerebrovascular events, platelet reactivity as assessed by VerifyNow P2Y12 assay, effect of statin on major adverse cardiovascular/cerebrovascular events, bleeding complications, and albumin-to-creatinine ratio to test the nephroprotective effect of cilostazol. Major adverse cardiovascular/cerebrovascular events will also be checked at 1, 2, and 3 years to test the 'legacy' effect of triple anti-platelet therapy that was prescribed for only 6 months after percutaneous coronary intervention.CILON-T trial will give powerful insight into whether triple anti-platelet therapy is superior to dual anti-platelet therapy in reducing ischemic events and platelet reactivity in the real-world unselected patients treated with drug-eluting stent for coronary heart disease. Also, it will verify the laboratory and clinical significance of drug interaction between lipophilic statin and clopidogrel.National Institutes of Health Clinical Trials Registry (ClinicalTrials.gov identifier# NCT00776828).Current guidelines recommend at least 6 months of dual anti-platelet agents, consisting of aspi
A potential oncogenic role of the commonly observed E2F5 overexpression in hepatocellular carcinoma
Yuzhu Jiang, Seon-Hee Yim, Hai-Dong Xu, Seung-Hyun Jung, So Young Yang, Hae-Jin Hu, Chan-Kwon Jung, Yeun-Jun Chung
World Journal of Gastroenterology , 2011,
Abstract: AIM: To explore the expression pattern of E2F5 in primary hepatocellular carcinomas (HCCs) and elucidate the roles of E2F5 in hepatocarcinogenesis.METHODS: E2F5 expression was analyzed in 120 primary HCCs and 29 normal liver tissues by immunohistochemistry analysis. E2F5-small interfering RNA was transfected into HepG2, an E2F5-overexpressed HCC cell line. After E2F5 knockdown, cell growth capacity and migrating potential were examined.RESULTS: E2F5 was significantly overexpressed in primary HCCs compared with normal liver tissues (P = 0.008). The E2F5-silenced cells showed significantly reduced proliferation (P = 0.004). On the colony formation and soft agar assays, the number of colonies was significantly reduced in E2F5-silenced cells (P = 0.004 and P = 0.009, respectively). E2F5 knockdown resulted in the accumulation of G0/G1 phase cells and a reduction of S phase cells. The number of migrating/invading cells was also reduced after E2F5 knockdown (P = 0.021).CONCLUSION: To our knowledge, this is the first evidence that E2F5 is commonly overexpressed in primary HCC and that E2F5 knockdown significantly repressed the growth of HCC cells.
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