Kyoung-Sun Lee

Konkuk University, Seoul, Seoul, South Korea

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Publications (8)9.69 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Gastric cancer is one of the major public health problems. Despite new chemotherapeutic treatments, the prognosis of gastric cancer remains poor. 5-Fluorouracil (5-FU) is used as a standard chemotherapy drug in gastric cancer. However, 5-FU resistance develops frequently and is a main cause of chemotherapy failure in human gastric cancer. Overexpression of cyclin D1 is related to rapid cell growth, a poor prognosis and increased chemoresistance in several types of cancers. In this study, we investigated whether treatment of gastric cancer cells with shRNA targeting cyclin D1 (ShCCND1) or 5-FU, alone or in combination, influences the activation of phosphorylated AKT (pAKT) and pNFκB, which are markers that are increased in 5-FU chemoresistance. We also investigated the effect of combined treatment with ShCCND1 and 5-FU on cell growth and chemosensitivity to 5-FU in the gastric cancer cell line AGS. The data showed that ShCCND1-mediated cyclin D1 downregulation in AGS cells significantly inhibited cell proliferation, cell mobility and clonogenicity. In addition, combined treatment with ShCCND1 and 5-FU significantly decreased the survival rate of AGS cells, compared to single-treatment with either agent. These results demonstrated that ShCCND1 increases 5-FU chemosensitivity, a conclusion that is also supported by the concomitant reduction in expression of pAKT and pNFκB, increase of G1 arrest and induction of apoptosis. Taken together, these data provide further evidence that therapeutic strategies targeting cyclin D1 may have the dual advantage of suppressing the growth of cancer cells, while enhancing their chemosensitivity.
    International Journal of Oncology 10/2013; · 2.66 Impact Factor
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    ABSTRACT: Klebsiella pneumoniae, Corynebacterium kutscheri, and Streptococcus pneumoniae are important pathogens that cause respiratory infections in laboratory rodents. In this study, we used species-specific triplex PCR analysis to directly detect three common bacterial pathogens associated with respiratory diseases. Specific targets were amplified with conventional PCR using the tyrB gene from K. pneumoniae, gyrB gene from C. kutscheri, and ply gene from S. pneumoniae. Our primers were tested against purified DNA from another eleven murine bacteria to determine primer specificity. Under optimal PCR conditions, the triplex assay simultaneously yielded a 931 bp product from K. pneumoniae, a 540 bp product from C. kutscheri, and a 354 bp product from S. pneumoniae. The triplex assay detection thresholds for pure cultures were 10 pg for K. pneumoniae and S. pneumoniae, and 100 pg for C. kutscheri. All three bacteria were successfully identified in the trachea and lung of experimentally infected mice at the same time. Our triplex PCR method can be used as a useful method for detecting pathogenic bacterial infections in laboratory rodents.
    Experimental Animals 01/2013; 62(1):35-40. · 1.46 Impact Factor
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    ABSTRACT: Deregulated Wnt signaling pathway is implicated in many hereditary diseases and tumorigenesis including colorectal cancer, hepatocellular carcinoma and gastric cancer. In this study, to assess the relationship between chemically induced gastric tumor and canonical Wnt signaling pathway in genetically intact mice, histopathological and quantitative mRNA analyses were performed in C57BL/6J mice given drinking water containing N-methyl-N-nitrosurea (MNU). 60.5% of gastric adenoma and 27.9% of adenocarcinoma were observed 48 weeks after first administration. Also, in immunohistochemical analysis, aberrant expressions of phospho-GSK-3β, β-catenin, cyclin D1, c-Myc, osteopontin and COX-2 were found. In double immunofluorescent-antibody stains, β-catenin accumulation was colocalized with other proteins. mRNA levels of cyclin D1, c-myc and COX-2 were relatively higher in adenocarcinoma. Altogether, canonical Wnt pathway was highly involved in MNU induced gastric neoplasia of C57BL/6J mice, and it could be a considerably suitable system for the study to examine the linkage between gastric tumorigenesis and the canonical Wnt pathway.
    Journal of Veterinary Medical Science 10/2012; · 0.88 Impact Factor
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    ABSTRACT: he principal objective of this experiment was to evaluate the anti-atherosclerotic activity of hempseed water extract in apolipoprotein E knockout (ApoE KO) mice. Fourteen male ApoE KO mice were divided into 2 groups and were treated via intragastric inoculation for 14 weeks. The hempseed water extract (HWE) inoculation group exhibited greater gains in weight as compared to the control group, which was inoculated with distilled water. Plaque lesion areas in the aortic sinus were reduced in the HWE group. Total plasma cholesterol, LDL-cholesterol, atherosclerotic index, and cardiac risk factor were all reduced in the HWE group. These results demonstrate that HWE is an excellent nutritional resource and evidences anti-atherosclerotic activity in ApoE KO mice. Further studies will be required to assess the pharmacological mechanisms underlying these effects.
    Food science and biotechnology 08/2012; 21(4). · 0.70 Impact Factor
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    ABSTRACT: Interleukin (IL)-10 is an anti-inflammatory cytokine that modulates sepsis by decreasing pro-inflammatory cytokine production and chemokine expression. In this study, IL-10-deficient and wild-type (WT) mice were infected with Corynebacterium kutscheri to determine if the absence of IL-10 altered the protective immunity and pathogenesis. After infection, IL-10 knockout (KO) mice had a higher survival rate than WT mice. The decrease of body weight and the increased weight of organs such as liver and spleen were greater in WT mice. Bacterial counts were significantly increased after inoculation in WT mice over those in IL-10 KO mice. WT mice had more granulomatous inflammation and coagulative necrosis in the liver and spleen, lymphocyte depletion in lymphoid follicles, and apoptosis of immune cells in the spleen. WT mice had significantly higher plasma concentrations of aspartate aminotransferase and alanine aminotransferase. Furthermore, more upregulation of tumor necrosis factor-α and IL-4 in the plasma, macrophage inflammatory protein-2, keratinocyte-derived chemokine, inducible nitric oxide synthase, and interferon-inducible protein 10 mRNA in the spleen were observed in WT mice after inoculation. These results suggest that the lack of IL-10 contributes to an increase in the systemic clearance of C. kutscheri, and that IL-10 plays a detrimental role in controlling systemic C. kutscheri infection.
    The Journal of Microbiology 04/2012; 50(2):301-10. · 1.28 Impact Factor
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    ABSTRACT: We report, herein, an attempt to determine whether an IL-10-induced immunological state affects the response of macrophages against Salmonella Typhimurium (ST). Pretreatment with mrIL-10 induced the intracellular invasion of ST into macrophages in a dose-dependent manner. It also activated AKT phosphorylation, cyclin D1, Bcl-X(L), and COX-2 upon ST infection, which may correlate with Salmonella's survival within the macrophages. However, I-κB phosphorylation was shown to be inhibited, along with the expression of TNF-α and MIP-2α mRNA. Therefore, IL-10 not only suppresses the bactericidal response of macrophages against ST, but also ultimately causes infected macrophages to function as hosts for ST replication.
    The Journal of Microbiology 12/2011; 49(6):1050-3. · 1.28 Impact Factor
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    ABSTRACT: The accurate and economical diagnosis of pathogenic bacteria is necessary for the microbiological control of laboratory animals. In this study, we developed a triplex PCR method for the direct detection of three common gastroenteric bacteria, Pseudomonas aeruginosa, Helicobacter hepaticus, and Salmonella typhimurium. Targets were specifically amplified by conventional PCR assay using a genomic fragment from P. aeruginosa, 16S ribosomal RNA from H. hepaticus, and the invA gene from S. typhimurium. To investigate the specificity of our primers, they were tested against purified DNA from many other bacterial species. There were no amplification products from other bacteria. Under optimized conditions, the triplex assay simultaneously yielded a 726-bp product from P. aeruginosa, a 417-bp product from H. hepaticus, and a 246-bp product from S. typhimurium. The detection limits of this assay in pure culture were 10 pg for P. aeruginosa, and 0.1 pg for H. hepaticus and S. typhimurium. All three bacteria were successfully detected in the liver, cecum, and feces of experimentally infected mice. This method is a useful and convenient assay that allows the simultaneous identification of bacterial pathogens in mice. Our triplex method will be used to improve quality control in the detection of pathogenic bacterial infections in laboratory animal facilities.
    Experimental Animals 01/2011; 60(1):65-70. · 1.46 Impact Factor
  • 한국실험동물학회 학술발표대회 논문집. 01/2008;