• Title/Summary/Keyword: time-dependent effect

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Effects of Chelidonium Majus Extract on Apoptosis Induction of MDA-MB-231 Human Breast Cancer Cells (백굴채 추출물이 MDA-MB-231 유방암 세포주에서 세포사멸에 미치는 효과)

  • Jang, Sae-Byul;Yoo, Dong-Youl
    • The Journal of Korean Obstetrics and Gynecology
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    • v.28 no.2
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    • pp.15-25
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    • 2015
  • Objectives : In this study, we investigated the anti-proliferative and apoptosis inducing effect of water extract of Chelidonium majus (CM) on human breast cancer cell MDA-MB-231. Methods : The MTT assay was used to assess cell proliferation. The expression of apoptosis related gene was assessed by quantitative Real-time PCR. Cell apoptosis detected by flow cytometry using Annexin-V/PI staining. Results : Our data revealed that CM inhibited the cell growth in a dose dependent manner (0, 62.5, 125, 250, 500 μg/ml). CM increased mRNA expression of pro-apoptotic genes Bax, caspase-3, and caspase-9. Annexin-V/PI staining assays revealed that apoptosis-induced cell death increased in a dose-dependent manner in cells. Conclusions : CM induces cell death in MDA-MB-231 human breast cancer cell and shows potentials for use in cancer therapy as apoptosis-inducing agent.

Mechanistic Studies of Cyclin-Dependent Kinase Inhibitor 3 (CDKN3) in Colorectal Cancer

  • Yang, Cheng;Sun, Jun-Jun
    • Asian Pacific Journal of Cancer Prevention
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    • v.16 no.3
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    • pp.965-970
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    • 2015
  • Colorectal cancer is one of the most severe subtypes of cancer, and has the highest propensity to manifest as metastatic disease. Because of the lack of knowledge of events that correlate with tumor cell migration and invasion, few therapeutic options are available. The current study aimed to explore the mechanism of colorectal cancer in hope of identifying the ideal target for future treatment. We first discovered the pro-tumor effect of a controversial cell cycle regulator, cylin-dependent kinase inhibitor 3 (CDKN3), which is highly expressed in colorectal cancer, and the possible related signaling pathways, by bioinformatics tools. We found that CDKN3 had remarkable effects in suppressing colorectal cancer cell proliferation and migration, inducing cell cycle arrest and apoptosis in a colorectal cancer cell line, SW480 cells. Our study, for the first time, provided consistent evidence showing overexpression of cell cycle regulator CDKN3, in colorectal cancer. The in vitro studies in SW480 cells revealed a unique role of CDKN3 in regulating cellular behavior of colorectal cancer cells, and implied the possibility of targeting CDKN3 as a novel treatment for colorectal cancer.

Purification and Characterization of a new anti-coagulant protein, PP27, of placenta protein (annexinⅤ-like protein) (새로운 인간(人間) 태반(胎盤)유래의 항응고(抗凝固) 단백질(蛋白質) PP27 (annexin Ⅴ형(型) 단백질(蛋白質))의 정제(精製)와 특성(特性))

  • Kim Jang-Hyun
    • The Journal of Pediatrics of Korean Medicine
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    • v.14 no.2
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    • pp.33-46
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    • 2000
  • It has long been known that Jahage(紫河車) extracts of Placenta hominis are effective for immunological and vascular diseases in human body and thus, was used a major constituent of traditional oriental medicines. From full-term human placenta, we have purified a new type anticoagulant protein, PP27, using different chromatographic techniques of a phenyl TSK gel 650M column, DEAE, HA and Mono-Q columns. PP27 showed single band on SDS-PAGE with a molecular mass (Mr) of 27 kDa under denaturing conditions and a calibrated Sepharose 4B column chromatography indicated a molecular mass of 23 kDa, indicating that the value is similar to those of other PP4 enzyme reported to date. Isoelectric point of PP27 was p15.2. The protein was found to inhibit the coagulation time in a concentration-dependent manner. PP27 was acted as a vascular anticoagulant of annexin type, inhibits the blood clotting process by binding of the essential lipids in a reaction which is dependent on $Ca2^+$ ions. In the presence of $Ca2^+$ ions, PP27 combines with platelet membranes neutralizing their procoagulant effect. Coagulation triggered by the addition of thromboplastin/ lipid- mixtures is extinguished by PP27.

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Application of Atomic Layer Deposition to Solid Oxide Fuel Cells

  • Kim, Eui-Hyun;Ko, Myeong-Hee;Hwang, Hee-Soo;Hwang, Jin-ha
    • Proceedings of the Korean Vacuum Society Conference
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    • 2014.02a
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    • pp.478.2-478.2
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    • 2014
  • Atomic layer deposition (ALD) provides self-limiting processes based on chemisorption-based reactions. Such unique features allow for superior step coverage, atomic-scale control in thickness, and surface-dependent reaction controls. Furthermore, the surface-limited deposition enables the artificial deposition of oxide and/or metallic materials onto the porous systems as long as the supply is guaranteed in terms of time in providing reactant species and removing the byproducts and redundant reactants. The unique feature of atomic layer deposition is applied to solid oxide fuel cells whose incorporates two porous cathode and anode compartments in addition to the ionic electrolyte. Specific materials are deposited to the surface sites of porous electrodes, with the aim to controlling the triple phase boundaries crucial for the optimized SOFC performances. The effect of ALD on the SOFC performance is characterized using current-voltage characteristics in addition to frequency-dependent impedance spectroscopy. The pros and cons of ALD-controlled SOFCs are discussed toward high-performance SOFC systems.

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Taurine Activates ERK2 and Induces the Production of Nitric Oxide in Osteoblast-like UMR-106 Cells

  • Park, Sung-Youn;Kim, Harriet;Kim, Sung-Jin
    • Proceedings of the Korean Society of Applied Pharmacology
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    • 1998.11a
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    • pp.145-145
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    • 1998
  • In the present study, we have demonstrated that taurine could stimulate the production of nitric oxide and the activity of ERK2 (extracellular signal regulated protein kinase or pp42 MAP kinase). Nitric oxide(NO), the product of inducible nitric oxide synthase(iNOS), is known to be implicated in the metabolism of bone. ERK cascade plays a key role in the gene expression of iNOS in osteoblastic cell. We investigated whether taurine (l-20mM) could stimulate ERK2 activity, nitric oxide production, and inducible nitric oxide synthase in osteoblast-like UMR-106 cells. Nitric oxide was measured spectophotometrically as nitrite and the activation of ERK2 and iNOS was studied using Western 145 blot analysis. Taurine increased the production of nitric oxide in a dose-dependent manner and the effect was reached to a maximum at 10 mM. The activation of iNOS were consistent with NO levels. The tyrosine phosphorylation of ERK2 was increased by taurine in a time-dependent manner. The these result suggest that taurine might stimulate the production of nitric oxide in osteoblast-like cells by the activation of ERK2 and could regulate the metabolism of bone via nitric oxide.

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Effect of ON/OFF Cycles of Ar Gas on Structural and Optical Properties of ZnO Nanostructure Grown by Vapor Phase Transport

  • Nam, Gi-Woong;Kim, Min-Su;Cho, Min-Young;Kim, So-A-Ram;Leem, Jae-Young
    • Proceedings of the Korean Vacuum Society Conference
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    • 2012.02a
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    • pp.415-415
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    • 2012
  • ZnO nanostructures were synthesized by a vapor phase transport process in a single-zone furnace within a horizontal quartz tube with an inner diameter of 38 mm and a length of 485 mm. The ZnO nanostructures were grown on Au-catalyzed Si(100) substrates by using a mixture of zinc oxide and graphite powders. The growth of ZnO nanostructures was conducted at $800^{\circ}C$ for 30 min. High-purity Ar and $O_2$ gases were pushed through the quartz tube during the process at a flow rate of 100 and 10 sccm, respectively. The sequence of ON/OFF cycles of the Ar gas flow was repeated, while the $O_2$ flow is kept constant during the growth time. The Ar gas flow was ON for 1 min/cycle and that was OFF for 2 min/cycle. The structure and optical properties of the ZnO nanostructures were investigated by field-emission scanning electron microscope, X-ray diffraction, temperature-dependent photoluminescence. The preferred orientation of the ZnO nanostructures was along c-axis with hexagonal wurtzite structure.

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Biphasic Activity of Chloroquine in Human Colorectal Cancer Cells

  • Park, Deokbae;Lee, Youngki
    • Development and Reproduction
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    • v.18 no.4
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    • pp.225-231
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    • 2014
  • Autophagy is a homeostatic degradation process that is involved in tumor development and normal development. Autophagy is induced in cancer cells in response to chemotherapeutic agents, and inhibition of autophagy results in enhanced cancer cell death or survival. Chloroquine (CQ), an anti-malarial drug, is a lysosomotropic agent and is currently used as a potential anticancer agent as well as an autophagy inhibitor. Here, we evaluate the characteristics of these dual activities of CQ using human colorectal cancer cell line HCT15. The results show that CQ inhibited cell viability in dose- and time-dependent manner in the range between 20 to 80 uM, while CQ did not show any antiproliferative activity at 5 and 10 uM. Cotreatment of CQ with antitumor agent NVP-BEZ235, a dual inhibitor of PI3K/mTOR, rescued the cell viability at low concentrations meaning that CQ acted as an autophagy inhibitor, but CQ induced the lethal effect at high concentrations. Acridine orange staining revealed that CQ at high doses induced lysosomal membrane permeabilization (LMP). High doses of CQ produced cellular reactive oxygen species (ROS) and cotreatment of antioxidants, such as NAC and trolox, with high doses of CQ rescued the cell viability. These results suggest that CQ may exert its dual activities, as autophagy inhibitor or LMP inducer, in concentration-dependent manner.

HEAT-UP AND COOL-DOWN TEMPERATURE-DEPENDENT HYDRIDE REORIENTATION BEHAVIORS IN ZIRCONIUM ALLOY CLADDING TUBES

  • Won, Ju-Jin;Kim, Myeong-Su;Kim, Kyu-Tae
    • Nuclear Engineering and Technology
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    • v.46 no.5
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    • pp.681-688
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    • 2014
  • Hydride reorientation behaviors of PWR cladding tubes under typical interim dry storage conditions were investigated with the use of as-received 250 and 485ppm hydrogen-charged Zr-Nb alloy cladding tubes. In order to evaluate the effect of typical cool-down processes on the radial hydride precipitation, two terminal heat-up temperatures of 300 and $400^{\circ}C$, as well as two terminal cool-down temperatures of 200 and $300^{\circ}C$, were considered. In addition, two cooling rates of 2.5 and $8.0^{\circ}C/min$ during the cool-down processes were taken into account along with zero stress or a tensile hoop stress of 150MPa. It was found that the 250ppm hydrogen-charged specimen experiencing the higher terminal heat-up temperature and the lower terminal cool-down temperature generated the highest number of radial hydrides during the cool-down process under 150MPa hoop tensile stress, which may be explained by terminal solid hydrogen solubilities for precipitation, and dissolution and remaining circumferential hydrides at the terminal heat-up temperatures. In addition, the slower cool-down rate generates the larger number of radial hydrides due to a cooling rate-dependent, longer residence time at a relatively high temperature that can accelerate the radial hydride nucleation and growth.

An Efficient Secretion of Type I Secretion Pathway-Dependent Lipase, TliA, in Escherichia coli: Effect of Relative Expression Levels and Timing of Passenger Protein and ABC Transporter

  • Eom Gyeong-Tae;Rhee Joon-Shick;Song Jae-Kwang
    • Journal of Microbiology and Biotechnology
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    • v.16 no.9
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    • pp.1422-1428
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    • 2006
  • An ABC transporter apparatus of the Gram-negative bacterial type I secretion pathway can be used as a secretory protein expression system in Escherichia coli. Four types of coexpression systems for the Pseudomonas fluorescens lipase gene, tliA, and its cognate ABC transporter gene cluster, tliDEF, were constructed. When the relative expression levels were changed by adding different concentrations of IPTG, the secretion (16.9 U/ml of culture) of TliA in E. coli [pTliDEFA-223+pACYC184] was significantly higher than E. coli [pKK223-3+pTliDEFA-184] secreting the lowest level of TliA (5.2 U/ml of culture). Maximal accumulation of the lipase secreted occurred in the mid-exponential phase, implying that the efficient protein secretion via an ABC transporter was restricted only to actively growing cells. Finally, the secretion level of TliA in E. coli [pTliDEFA-223+pACYC184] was increased to 26.4 U/ml by inducing gene expression at the culture initiation time. These results indicate that a significant increase in the ABC transporter-dependent protein secretion can be achieved by simply controlling the relative expression levels between the ABC transporter and its passenger protein, even in the recombinant E. coli cells.

Effect of Cordycepin on the Expression of the Inflammatory Cytokines TNF-alpha, IL-6, and IL-17A in C57BL/6 Mice

  • Seo, Min Jeong;Kim, Min Jeong;Lee, Hye Hyeon;Park, Jeong Uck;Kang, Byoung Won;Kim, Gi-Young;Rhu, En Ju;Kim, Jung-In;Kim, Kwang Hyuk;Jeong, Yong Kee
    • Journal of Microbiology and Biotechnology
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    • v.23 no.2
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    • pp.156-160
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    • 2013
  • Culture supernatants of splenocytes from C57BL/6 mice were exposed to 0.3, 1.0, and 3.0 ${\mu}g/ml$ cordycepin plus 3.0 ${\mu}g/ml$ lipopolysaccharide (LPS) to investigate the effects of cordycepin (3'-deoxyadenosine) on the production of inflammatory cytokines. Coadministration of 3.0 ${\mu}g/ml$ cordycepin with LPS in cultured murine spleen cells significantly diminished expression of the inflammatory cytokines tumor necrosis factor-${\alpha}$ and interleukin-6 (IL-6) in a time-dependent manner. Expression of the inflammatory cytokine IL-17A was substantially downregulated in a timeand concentration-dependent manner at all cordycepin concentrations. These findings suggest that cordycepin downregulates the immediate hypersensitivity reaction stimulated by LPS.