Sook-Young Lee

Seoul National University Bundang Hospital, Seoul, Seoul, South Korea

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Publications (32)70.07 Total impact

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    ABSTRACT: We investigated Licochalcone-A (Lico-A)-induced apoptosis and the pathway underlying its activity in a pharyngeal squamous carcinoma FaDu cell line. Lico-A purified from root of Glycyrrhiza inflata had cytotoxic effects, significantly increasing cell death in FaDu cells. Using a cell viability assay, we determined that the IC50 value of Lico-A in FaDu cells was approximately 100 µM. Chromatin condensation was observed in FaDu cells treated with Lico-A for 24 h. Consistent with this finding, the number of apoptotic cells increased in a time-dependent manner when FaDu cells were treated with Lico-A. TRAIL was significantly up-regulated in Lico-A-treated FaDu cells in a dose-dependent manner. Apoptotic factors such as caspases and PARP were subsequently activated in a caspase-dependent manner. In addition, levels of pro-apoptotic factors increased significantly in response to Lico-A treatment, while levels of anti-apoptotic factors decreased. Lico-A-induced TRAIL expression was mediated in part by a MAPK signaling pathway involving ERK1/2 and p38. In xenograft mouse model, Lico-A treatment effectively suppressed the growth of FaDu cell xenografts by activating caspase-3, without affecting the body weight of mice. Taken together, these data suggest that Lico-A has potential chemopreventive effects and should therefore be developed as a chemotherapeutic agent for pharyngeal squamous carcinoma.
    Food and Chemical Toxicology. 01/2015;
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    ABSTRACT: Licochalcone A (Lico-A) is a natural phenol licorice compound with multiple bioactivities, including anti-inflammatory, anti-microbial, anti-fungal and osteogenesis-inducing properties. In the present study, we investigated the Lico-A-induced apoptotic effects and examined the associated apoptosis pathway in KB human oral cancer cells. Lico-A decreased the number of viable KB oral cancer cells. However, Lico-A did not have an effect on primary normal human oral keratinocytes. In addition, the IC50 value of Lico-A was determined to be ~50 µM following dose-dependent stimulation. KB oral cancer cells stimulated with Lico-A for 24 h showed chromatin condensation by DAPI staining, genomic DNA fragmentation by agarose gel electrophoresis and a gradually increased apoptotic cell population by FACS analysis. These data suggest that Lico-A induces apoptosis in KB oral cancer cells. Additionally, Lico‑A‑induced apoptosis in KB oral cancer cells was mediated by the expression of factor associated suicide ligand (FasL) and activated caspase-8 and -3 and poly(ADP-ribose) polymerase (PARP). Furthermore, in the KB oral cancer cells co-stimulation with a caspase inhibitor (Z-VAD-fmk) and Lico-A significantly abolished the apoptotic phenomena. Our findings demonstrated that Lico‑A-induced apoptosis in KB oral cancer cells involves the extrinsic apoptotic signaling pathway, which involves a caspase-dependent FasL-mediated death receptor pathway. Our data suggest that Lico-A be developed as a chemotherapeutic agent for the management of oral cancer.
    Oncology Reports 12/2013; · 2.19 Impact Factor
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    ABSTRACT: A novel fibrinolytic enzyme was purified from Lyophyllum shimeji, a popular edible mushroom in Asia. The enzyme was purified using combination of anion exchange chromatography on a Mono Q 5/5 column and size exclusion gel filtration chromatography on Superdex 200 100/300 column. This purification protocol resulted 80.9-fold purification of the enzyme and a final yield of 5.7%. The molecular weight of the purified enzyme was estimated to be 21 kDa by SDS-PAGE and size exclusion gel filtration. The N-terminal amino acid sequence was found to be ITFQSASP, which is dissimilar from that of known fibrinolytic enzymes. The purified enzyme was a neutral protease with an optimal reaction pH and temperature of 8.0 and 37°C, respectively. Enzymatic activity was inhibited by Cu(2+) and Co(2+). It was also significantly inhibited by PMSF and TPCK. Furthermore, it was found to exhibit a higher specificity for S-7388, a well-known chymotrypsin chromogenic substrate, indicating chymotrypsin like serine metalloprotease. The relative fibrinolytic activity of 5 μg purified enzyme have two fold more activity than 1 unit/ml of plasmin on fibrin plate. Furthermore, purified enzyme preferentially hydrolyzed the Aα-chain followed by the Bβ- and γ-chain of fibrinogen, which is precursor of fibrin. Therefore, these data suggests that the fibrinolytic enzyme derived from edible mushroom, L. shimeji, might be useful for thrombolytic therapy and preventing thrombotic disease.
    Journal of Bioscience and Bioengineering 12/2013; · 1.74 Impact Factor
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    ABSTRACT: MicroRNA (miRNA) is a small noncoding RNA molecule, 19-25 nucleotides in length, which regulates several pathways including cell development, cell proliferation, carcinogenesis, apoptosis, etc. In this study, the over-expression of microRNA-205 (miR-205) increased the number of apoptotic cells by at least 4 times compared to the control. In addition, over-expressed miRNA in KB oral cancer cells triggered apoptosis via the caspase cascade, including the cleavage of caspase-9, caspase-7, caspase-3, and PARP. Flow cytometry showed that apoptotic cell death was increased significantly by 35.33 % in KB oral cancer cells with over-expressed miR-205 compared to the control. The microarray data showed that axis inhibitor protein 2 (Axin2) was down-regulated in KB oral cancer cells transfected with miR-205. In addition, Axin2 was down-regulated by approximately 50 % by over-expressed miR-205 at both the mRNA and protein levels. Interestingly, Axin2 was up-regulated in KB oral cancer compared to human normal oral keratinocytes. Furthermore, the cell cytotoxicity and apoptotic population of KB oral cancer cells were increased significantly after Axin2 siRNA transfection. These results suggest that Axin2 is might be as potential oncogene in KB oral cancer cells. The luciferase assay showed that over-expressed miR-205 in KB oral cancer cells suppressed AXIN2 expression through an interaction with its own binding site at AXIN2 3'UTR (64-92). These results suggest that miR-205 is a novel anti-oncogenic miRNA in KB oral cancer cells, and may have potential applications in oral cancer therapy.
    Molecular and Cellular Biochemistry 10/2013; · 2.39 Impact Factor
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    ABSTRACT: Abstract Context: Saussurea lappa Dence (Compositae) is used as a traditional herbal medicine to treat abdominal pain and tenesmus in East Asia. Current studies have shown that S. lappa has anticancer activity in divergent of cancer cells. However, the effects of S. lappa on oral cancer and its mechanisms of action have yet to be elucidated. Objective: To explore its potential chemotherapeutic effects and mechanism of cell growth inhibition on human oral cancer cells. Materials and methods: The dried roots of S. lappa were used in this study. Cell viability of KB cells was evaluated by 3-[4, 5-dimethylthiazol-2-yl]-2, 5-diphenyltetrazolium bromide assay after treatment with 30 µg/ml of methanol extract from the dried roots of S. lappa. To understand whether its effect on cell death is related with apoptosis pathway, we performed DNA fragmentation assay, western blot, caspase activity assay and fluorescence-activated cell sorting (FACS) analysis. Results: Treatment of S. lappa extract onto KB cells reduced cell viability significantly with an IC50 value of 30 µg/ml. The formation of a DNA ladder was observed starting at the 24 h treatment. In western blotting analysis, the S. lappa extract induced the proteolytic processing of caspase-3, -9 and poly (ADP-ribose) polymerase, a significant increase of Bax and marked reduction of Bcl-2. We also confirmed the activation of caspase-3/-7 in living KB cells by fluorescence microscopy. Conclusion: These results suggested that S. lappa extract inhibited cell proliferation through the apoptosis pathway in KB human oral cancer cells.
    Pharmaceutical Biology 07/2013; · 1.21 Impact Factor
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    ABSTRACT: This study aimed to evaluate the bone regeneration relative to tooth powder and tricalcium phosphate (TCP) mixing ratios using the rabbit cranium defect model. The tooth powder was mixed with TCP in 1:1, 3:1, and 1:3 ratios, and the different ratios were implanted in the rabbit cranium defect for 4 and 8 weeks. Powders crystal structure evaluated using scanning electron microscopy (SEM), attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), and new bone formation (NBF) was analyzed using micro-computed tomography (CT) and histologic examination. NBF in the control group was restricted to the defect margins. More NBF was observed around the defect margins in the experimental groups compared with the control group. Specifically, active NBF was identified around the implant materials of the centrifugal part of the defect and defect margins in the 3:1 tooth powder: TCP group. Our results suggested that tooth powder and TCP may be useful in bone regeneration.
    Journal of Biomedical Nanotechnology 03/2013; 9(3):475-8. · 7.58 Impact Factor
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    ABSTRACT: Barrier membranes for guided bone regeneration (GBR) were prepared by a solvent casting method using solutions of poly(L-lactic acid) (PLLA) and chitosan. PLLA and PLLA/chitosan membranes were treated with ammonia gas plasma. PLLA/chitosan membranes were successfully fabricated, and the surface of the PLLA/chitosan membrane was clearly modified by NH3 plasma treatment according to attenuated total reflectance (ATR-FTIR), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) analyses. Additionally, water contact angle testing indicated that the hydrophilicity of these membranes was significantly increased. MG-63 cells were cultured on each type of membrane, and cell viability was examined using an MTT assay. After one week of culturing, MG-63 cells were more abundant on PLLA/chitosan membranes than on PLLA membranes. The cell viability of PLLA/chitosan membranes with plasma treatment was significantly higher than that of PLLA membranes. These results suggest that this plasma-treated membrane is suitable for GBR and is a promising source of bioactive membrane material for bone regeneration.
    Journal of Nanoscience and Nanotechnology 03/2013; 13(3):1691-5. · 1.34 Impact Factor
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    ABSTRACT: The purpose of this study was to evaluate the effect of tooth ash and platelet-rich plasma (PRP), and platelet-rich fibrin (PRF) grafts into bone defects around implants on bone formation. Six adult dogs were used as experimental subjects. Graft materials were used to create a particulate material. Forty-eight tapered-type implants, 3.7 mm in diameter, 10 mm in length, and with surface treated with hydroxyapatite (HA) coating, were used as implant fixtures. Using a trephine bur, four bone defects were formed and implants were placed in the femurs of the adult dogs. Bone grafts were not performed in the control group. Tooth ash was grafted into the defects in group 1. In group 2, a mixture of tooth ash and PRP (1:1 ratio by volume) was grafted into the defects. In group 3, a mixture of tooth ash and PRF (ratio of 1:1) was grafted in the defect area. Animals were sacrificed after 4 or 8 weeks. Based on histopathological examination, the amount and rate of new bone formation were evaluated. Histomorphometric examination revealed that the rate of new bone formation in group 3 of the 4-week group was significantly higher than that in the control group. In addition, in the 8-week group, a significant increase in new bone formation was confirmed in group 3. In this study, a bone graft method using a mixture of tooth ash and PRF was found to increase new bone formation compared to the method using PRP. In addition, it was confirmed that this effect was more prominent in the initial stage of the bone graft.
    Journal of Biomedical Nanotechnology 03/2013; 9(3):535-7. · 7.58 Impact Factor
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    ABSTRACT: MicroRNA (miRNA) is a form of small noncoding RNA that regulates the expression of genes either by inhibiting mRNA translation or by inducing its degradation. Small microRNA play important roles in regulating a large number of cellular processes, including development, proliferation and apoptosis. This study examined the biological functions of miR-205 as a tumor suppressor in KB oral cancer cells. The results showed that miR-205 expression was significantly lower in KB oral cancer cells than in human normal oral keratinocytes. Furthermore, the miR-205 over-expressed in KB oral cancer cells increased the cell cytotoxicity and induced apoptosis through the activation of caspase-3/-7. The transfection of miR-205 into KB oral cancer cells strongly induced IL-24, a well known cytokine that acts as a tumor suppressor in a range of tumor tissues. In addition, miR-205 targeted the IL-24 promoter directly to induce gene expression. Overall, miR-205 has significant therapeutic potential to turn on silenced tumor suppressor genes by targeting them with miRNA.
    Molecules and Cells 12/2012; · 14.46 Impact Factor
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    ABSTRACT: OBJECTIVES: This study evaluated the surface structures and physicochemical characteristics of a novel autogenous tooth bone graft material currently in clinical use. STUDY DESIGN: The material's surface structure was compared with a variety of other bone graft materials via scanning electron microscope (SEM). The crystalline structure of the autogenous tooth bone graft material from the crown (AutoBT crown) and root (AutoBT root), xenograft (BioOss), alloplastic material (MBCP), allograft (ICB), and autogenous mandibular cortical bone were compared using x-ray diffraction (XRD) analysis. The solubility of each material was measured with the Ca/P dissolution test. RESULTS: The results of the SEM analysis showed that the pattern associated with AutoBT was similar to that from autogenous cortical bones. In the XRD analysis, AutoBT root and allograft showed a low crystalline structure similar to that of autogenous cortical bones. In the CaP dissolution test, the amount of calcium and phosphorus dissolution in AutoBT was significant from the beginning, while displaying a pattern similar to that of autogenous cortical bones. CONCLUSIONS: In conclusion, autogenous tooth bone graft materials can be considered to have physicochemical characteristics similar to those of autogenous bones.
    Oral surgery, oral medicine, oral pathology and oral radiology. 08/2012; 117(1):e39-e45.
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    ABSTRACT: The purpose of this study was to compare the cytokine profiles of the synovial fluid from the temporomandibular joint (TMJ) spaces of normal individuals and temporomandibular disorder (TMD) patients. Thirty-four patients with planned orthognathic surgery did not present abnormalities of the TMJ on magnetic resonance images and radiographs and did not show the symptoms identified by the Research Diagnostic Criteria for TMD (RDC-TMD); as a result, they were assigned to the control group. Twenty-two patients who sought treatment for TMD during the same period were assigned to the TMD group. Synovial fluid was collected from superior TMJ spaces, and cytokine expression was analysed by an enzyme-linked immunosorbent assay (ELISA). Significant differences were tested using Fisher's exact test (p<0.05). Granulocyte Macrophage Colony stimulating Factor (GM-CSF), interferon (INF), interleukin (IL)-1β, IL-2, IL-6, IL-8, IL-10 and tumour necrosis factor (TNF)-α were detected in the TMD group, whereas no cytokines were detected in the control group. The most prevalent cytokines in the TMD group were IL-1β, IL-6 and GM-CSF. IL-4 and IL-5 were not detected in either the TMD group or in the control group. None of the cytokines that were detected in patients with TMD were found in the articular spaces of normal individuals.
    Journal of cranio-maxillo-facial surgery: official publication of the European Association for Cranio-Maxillo-Facial Surgery 03/2012; · 1.25 Impact Factor
  • Jin-Ju Park, Sook-Young Lee, Su-Gwan Kim
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    ABSTRACT: The purpose of this study was to examine the toothbrushing behavior of the citizens, their use of dentifrice, awareness of the importance of dentifrice purchase and consciousness of dentifrice containing the extract of Chamaecyparis obtusa in the city of Gwangju. It's basically meant to provide some informations on the development of oral health supplies involving dentifrice containing the extract of Chamaecyparis obtusa in that city in an effort to help the city serve as a hub of the dental industry. The subjects in this study were the selected citizens in the city of Gwangju. As a result of analyzing their awareness of the importance of the considerations for the purchase and use of dentifrice, they gave 68.2% overall. They gave the highest marks of 83.3% to the importance of effect. As for the importance of each item, they gave the highest marks of 85.1% to the importance of the prevention of dental caries. Concerning differences in awareness of the importance of the external purchase factors according to age, every age group placed the most importance on inspection by the certification authorities except for those who were in their 40s and 60s, and the respondents who were in their 40s and 60s attached more importance to price than the other items. Regarding differences in awareness of the importance of effectiveness according to age, those who were under the age of 20 gave the highest marks of 79.8% to the importance of dental-caries prevention and whitening effects. As a result of asking them whether they had an intention to use dentifrice containing the extract of Chamaecyparis obtusa if this dentifrice would be developed, 54.6% replied they had the intention. When they were asked another question whether they thought this dentifrice would have an effect on oral health, 55.1% answered they thought so. 33.8% expected this dentifrice to have a primary effect on the prevention of dental caries. Given the findings of the study, full-scale R&D efforts should be directed into the development of dentifrice containing the extract of chamaecyparis obtusa in the future.
    The Journal of the Korea Contents Association. 01/2012; 12(12).
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    ABSTRACT: Erbium-doped yttrium aluminum garnet (Er:YAG) lasers have been used in dentistry for cutting bone and removal of caries. The purpose of this study was to evaluate the bone healing in a skull defect prepared in rats using various instruments including Er:YAG laser. The 7 mm calvarial defects were created in 45 rats and 45 rats were divided into three groups (n = 15): a high-speed rotation engine with carbide round bur (2-mm diameter), a low-speed rotation engine with carbide round bur (2-mm diameter), and an Er:YAG laser. Specimens obtained after 3 days or 4 or 8 weeks were submitted for histological analysis. Three days after surgery, no bone formation had occurred in any of the groups. Four weeks after surgery, 90 ± 8.16% new bone formation was observed in the high-speed group, and 8 weeks after surgery, 100 ± 0% new bone formation was observed in the low- and high-speed groups. There were significant differences among the periods after surgery, but no significant differences were observed among final results with in different device groups.
    Japanese Journal of Applied Physics 01/2012; 51(1). · 1.06 Impact Factor
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    ABSTRACT: A novel barrier membrane composed of poly(lactic-co-glycolic acid) particles loaded with dexamethasone (DEX) as a bioactive molecule was produced via a modified nanoprecipitation method without any mixing. The particle membranes had a bilayer structure: one side was smooth and had a compact surface that was connected to larger particles, while the opposite side was rough, porous and connected to smaller particles. Additionally, a cross-section of the particle membrane had a porous structure with nano and micro sized irregular pores. Process optimization revealed that NaCl concentration in the water phase, with acetone as solvent and water as a non-solvent, played critical roles in determining the properties of the particle membranes, such as DEX encapsulation efficiency, thickness and surface morphologies of the particle membranes. A novel barrier membrane containing DEX using polymer particle drug capture technology has been successfully developed.
    Biotechnology Letters 12/2011; 34(4):779-87. · 1.74 Impact Factor
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    ABSTRACT: In general, an antimicrobial test for screening anti-caries natural extracts was performed by measuring the minimum bactericidal concentration (MBC) against the type strains of mutans streptococci. However, it is unclear if the antimicrobial efficiency of natural extracts on the type strains of mutans streptococci is the same on the clinical strains. In this study, we introduced a bacterial model system for the screening of anti-caries and determining the optimal concentration of them to develop oral hygiene products for Korean populations.
    The Journal of Microbiology 02/2011; 49(1):165-8. · 1.28 Impact Factor
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    ABSTRACT: The purpose of this study was to examine the effect of 2-aminobicyclo-(2,2,1)-heptane-2-carboxylic acid (BCH), an inhibitor of L-type amino acid transporters, on the cell growth suppression in KB human oral cancer cells and to study the roles of cell cycle regulatory factors in the BCH-induced growth inhibition. The effect of BCH on cell growth suppression and the influence of BCH to cell cycle regulatory factors in KB cell growth inhibition were examined using cell cycle analysis, immunoblotting and immunoprecipitation. The BCH treatment induced cell cycle arrest at G1 phase in KB cells. The expression of cyclin D3 was remarkably decreased by BCH treatment. The BCH inhibited the expression of cyclin-dependent protein kinase 6 (CDK6) in a time-dependent manner. In addition, the expression of CDK inhibitor p27 was increased by BCH treatment in KB cells, but not CDK inhibitors p21 and p15. These results suggest that, in KB cells, the inhibition of LAT1 by BCH causes cell cycle arrest at G1 phase by inhibiting cyclin D3-CDK6 complex whereas increasing expression of a CDK inhibitor p27.
    Biological & Pharmaceutical Bulletin 01/2010; 33(7):1117-21. · 1.85 Impact Factor
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    ABSTRACT: To elucidate the mechanisms involved in adaptation of lung epithelial cells to cadmium (Cd), we established a cell line that exhibits Cd-resistance (RWI38). RWI38 showed approximately 5-fold greater Cd-resistance (MTT assays) than WI38 cells, and cross-resistance to Zn and cisplatin. RWI38 cells also demonstrated an upregulated level of multidrug resistance-associated protein (MRP) and metallothionein (MT) (as shown by Western blot analysis and RT-PCR studies). The protein level of MRP decreased after Cd exposure in WI38 cells, but was sustained at high levels in RWI38 cells, leading led to enhanced calcein efflux. Cd induced Akt phosphorylation in RWI38 but not WI38 cells; this was prevented by probenecid or siRNA for MRP, both of which led to enhanced cell death, as demonstrated by capsase-3 activation and decreased cell viability. These results suggest a functional role for MRP in the regulation of the Akt pathway as well in the efflux pumping of drugs, thereby contributing toward the adaptation of cells to Cd toxicity. The findings of this study could be potentially beneficial in the design of therapeutic targets for Cd-induced tumor progression.
    Archives of Pharmacal Research 07/2009; 32(6):883-91. · 1.75 Impact Factor
  • Sook-Young Lee, Young-Nam Chun, Sun-Il Kim
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    ABSTRACT: The effects of various factors involved in phenol degradation through an immobilized activated sludge with a photo-crosslinked resin were investigated. The immobilized activated sludge showed a higher relative activity of phenol degradation across a broader range of pH than free activated sludge. A higher rate of phenol degradation was observed when the bead size was smaller. The phenol degradation in the free activated sludge was inhibited at the 3000mg/L of phenol, while that in the immobilized activated sludge was maintained at the same concentration for 28h without any inhibition. The degradation rates of phenol were not directly proportional to the increasing amount of immobilized bead dosage, but the phenol degradation was completed in a shorter time than that for the free activated sludge. For the repeated reaction of immobilized activated sludge, the relative activity is increased up to eight times after seven repeated initial cycles. Continued treatment of immobilized activated sludge showed more than 95% of phenol removal efficiency under a loading rate of 5.59kg-phenol/(m3d), which is twice as large as the loading rate for the free activated sludge.
    Journal of Industrial and Engineering Chemistry 05/2009; 15(3):323-327. · 2.06 Impact Factor
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    ABSTRACT: The Angelica decursiva has been used in Korean traditional medicine as an antitussive, an analgesic, an antipyretic and a cough remedy. However, its anti-tumor activity has been completely unknown. In this study, therefore, we have examined the cytotoxic activity of ethanol extract of Angelica decursiva root (EEAD), and the mechanism of cell death exhibited by EEAD in C6 rat glioma cells. Treatment of EEAD in C6 cells induced the apoptotic cell death in a concentrationand a time-dependent manner. Furthermore, the proteolytic processing of caspase-3, -7, and -9 was increased by EEAD treatment in C6 cells. In addition, activation of caspase-3 and -7 was detected in living C6 cells by fluorescence microscopy. These results suggest that EEAD can induce the suppression of cell growth and cell apoptosis in C6 rat glioma cells, and therefore, that it may have potential properties for anti-tumor drug discovery.
    Journal of the Korean Society for Applied Biological Chemistry 01/2009; 52(3). · 0.54 Impact Factor
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Publication Stats

260 Citations
70.07 Total Impact Points


  • 2012
    • Seoul National University Bundang Hospital
      • Department of Oral and Maxillofacial Surgery
      Seoul, Seoul, South Korea
  • 2006–2012
    • Chosun University
      • • Oral Biology Research Institute
      • • Department of Biotechnology
      Goyang, Gyeonggi, South Korea
  • 2005
    • Dongshin University
      Eidō, North Chungcheong, South Korea