• Asian Pacific Journal of Cancer Prevention
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• v.16 no.15
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• pp.6753-6759
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• 2015

Background: Loss of function of the p53 gene is implicated in defective apoptotic responses of tumors to chemotherapy. Although the pro-apoptotic roles of eugenol and capsaicin have been amply reported, their dependence on p53 for apoptosis induction in gastric cancer cells is not well elucidated. The aim of the study was to elucidate the role of p53 in the induction of apoptosis by eugenol and capsaicin in a human gastric cancer cell line, AGS. Materials and Methods: AGS cells were incubated with or without various concentrations of capsaicin and eugenol for 12 hrs, in the presence and absence of p53 siRNA. Cell cycling, annexin V and expression of apoptosis related proteins Bax, Bcl-2 ratio, p21, cyt c-caspase-9 association, caspase-3 and caspase-8 were studied. Results: In the presence of p53, capsaicin was a more potent pro-apoptotic agent than eugenol. However, silencing of p53 significantly abrogated apoptosis induced by capsaicin but not that by eugenol. Western blot analysis of pro-apoptotic markers revealed that as opposed to capsaicin, eugenol could induce caspase-8 and caspase-3 even in the absence of p53. Conclusions: Unlike capsaicin, eugenol could induce apoptosis both in presence and absence of functional p53. Agents which can induce apoptosis irrespective of the cellular p53 status have immense scope for development as potential anticancer agents.

• BMB Reports
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• v.51 no.1
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• pp.21-26
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• 2018

Delta-like ligand 4 (DLL4) expression in endothelial cells is intimately associated with angiogenic sprouting and vascular remodeling, but the precise mechanism of transcriptional regulation of DLL4 remains incompletely understood. Here, we showed that LIM-domain binding protein 2 (LDB2) plays an important role in regulating basal DLL4 and VEGF-induced DLL4 expression. Knockdown of LDB2 using siRNA enhanced endothelial sprouting and tubular network formation in vitro. Injection of ldb2-morpholino resulted in defective development of intersegmental vessels in zebrafish. Reduction or over-expression of LDB2 in endothelial cells decreased or increased DLL4 expression. LDB2 regulated DLL4 promoter activity by binding to its promoter region and the same promoter region was occupied and regulated by the LMO2/TAL1/GATA2 complex. Interestingly, LDB2 also mediated VEGF-induced DLL4 expression in endothelial cells. The regulation of DLL4 by the LDB2 complex provides a novel mechanism of DLL4 transcriptional control that may be exploited to develop therapeutics for aberrant vascular remodeling.

• Journal of Animal Reproduction and Biotechnology
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• v.36 no.4
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• pp.307-313
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• 2021

Traf4 (Tumor necrosis factor Receptor Associated Factor 4) is a member of the tumor necrosis factor receptor (TNFR) - associated factors (TRAFs) family. TRAF4 is overexpressed in tumor cells such as breast cancer and associated with cytoskeleton and membrane fraction. Interestingly, TRAF4 was localized with tight junctions (TJs) proteins including OCLN and TJP1 in mammary epithelial cells. However, the expression patterns and biological function of Traf4 were not examined in preimplantation mouse embryos although Traf4-deficient mouse showed embryonic lethality or various dramatic malformation. In this study, we examined the temporal and spatial expression patterns of mouse Traf4 during preimplantation development by qRT-PCR and immunostaining, and its biological function by using siRNA injection. We found upregulation of Traf4 from the 8-cell stage onwards and apical region of cell - cell contact sites at morula and blastocyst embryos. Moreover, Traf4 knockdown led to defective TJs without alteration of genes associated with TJ assembly but elevated p21 expression at the KD morula. Taken together, Traf4 is required for TJs assembly and cell proliferation during morula to blastocyst transition.

• Tuberculosis and Respiratory Diseases
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• v.47 no.1
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• pp.13-25
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• 1999

Background: Ineffective cell-mediated immune response in human tuberculosis is associated with a depressed Thl cytokine response and reduced production of IFN-$\gamma$. Most persons infected with Mycobacterium tuberculosis are healthy tuberculin reactors with protective immunity, but a minority with ineffective immunity develop extensive pulmonary tuberculosis. The cell-mediated immune response is an important aspect of host resistance to mycobacterial infection and is believed to be tightly regulated by a balance between Th1 cytokines including IFN-$\gamma$, IL-12, IL-18, regulated on activation, normal T cell expressed and secreted (RANTES) and Th2 counterparts such as IL-4, monocyte chemoattractant protein-l (MCP-l). Methods: Proliferation and mRNA expression of IFN-$\gamma$, RANTES and MCP-l by RT-PCR in peripheral blood mononuclear cells (PBMCs) in response to in vitro stimulation with mycobacterial antigens were compared in pulmonary tuberculosis patients with cured and treatment failure and in tuberculin-positive and tuberculin-negative healthy subjects. Results: Defective proliferative responsiveness to aqueous TSP antigen was involved with treatment failure tuberculosis patients. Aqueous TSP antigen-induced IFN-$\gamma$ and RANTES mRNA expression was decreased in treatment failure tuberculosis patients compared with healthy tuberculin reactors and cured tuberculosis patients (23.1 % versus 90.0% for IFN-$\gamma$ and 46.2% versus 70.0% versus 46.2% for RANTES). The frequency of MCP-l mRNA expression to aqueous TSP antigen in treatment failure tuberculosis patients was greater than in healthy tuberculin reactors and cured tuberculosis patients (76.9% versus 40.0%). Conclusion: The increasing expression of MCP-1 mRNA in response to aqueous TSP antigen might be predicted to favor Th1 responses and restricted Th1 responses in treatment failure of pulmonary tuberculosis.

• Molecules and Cells
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• v.22 no.3
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• pp.343-352
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• 2006

Sialic acid is a sugar typically found at the N-glycan termini of glycoproteins in mammalian cells. Lec3 CHO cell mutants are deficient in epimerase activity, due to a defect in the gene that encodes a bifunctional UDP-GlcNAc 2-epimerase/ManNAc kinase (GNE). Sialic acid modification on the cell surface is partially affected in these cells. We have mutagenized Lec3 CHO cells and isolated six mutants (termed C2m) deficient in the cell surface expression of polysialic acid (PSA). Mutant C2m9 was partially defective in expression of cell-surface PSA and wheat germ agglutinin (WGA) binding, while in the other five mutants, both cell-surface PSA and WGA binding were undetectable. PSA expression was restored by complementation with the gene encoding the CMP-sialic acid transporter (CST), indicating that CST mutations were responsible for the phenotypes of the C2m cells. We characterized the CST mutations in these cells by Northern blotting and RT-PCR. C2m9 and C2m45 carried missense mutations resulting in glycine to glutamate substitutions at amino acids 217 (G217E) and 256 (G256E), respectively. C2m13, C2m39 and C2m31 had nonsense mutations that resulted in decreased CST mRNA stability, and C2m34 carried a putative splice site mutation. PSA and CD15s expression in CST-deficient Lec2 cells were partially rescued by G217E CST, but not by G256E CST, although both proteins were expressed at similar levels, and localized to the Golgi. These results indicate that the novel missense mutations isolated in this study affect CST activity.

• Molecules and Cells
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• v.40 no.6
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• pp.401-409
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• 2017

The primary cilium is a non-motile microtubule-based organelle that protrudes from the surface of most human cells and works as a cellular antenna to accept extracellular signals. Primary cilia assemble from the basal body during the resting stage ($G_0$ phase) and simultaneously disassemble with cell cycle re-entry. Defective control of assembly or disassembly causes diverse human diseases including ciliopathy and cancer. To identify the effective compounds for studying primary cilium disassembly, we have screened 297 natural compounds and identified 18 and 17 primary cilium assembly and disassembly inhibitors, respectively. Among them, the application of KY-0120, identified as Brefeldin A, disturbed Dvl2-Plk1-mediated cilium disassembly via repression of the interaction of $CK1{\varepsilon}-Dvl2$ and the expression of Plk1 mRNA. Therefore, our study may suggest useful compounds for studying the cellular mechanism of primary cilium disassembly to prevent ciliopathy and cancer.

• The Journal of Korean Society of Virology
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• v.30 no.1
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• pp.83-99
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• 2000

A defective HIV-1 helper virus DNA, pHyPC, was assembled by deleting the RNA packaging signal, env, nef and the 3'LTR sequences. HIV-1 like virus particles that carry the HIV-1 receptor, CD4 were generated by co expression of pHyPC and plasmid DNAs encoding different chimeric CD4 proteins. The CD4 particles, sharing the CD4 ectodomain, precisely fused to different membrane anchors. CD4(+) particles specifically bound to HIV-1 Env expressing cells, but any signs of infection into these cells were not detected. Binding was only partially blocked by either polyclonal anti-CD4 antibodies or by high concentrations of soluble CD4. Surprisingly, CD4(+) particles also adsorbed to HeLa, CHO, NIH3T3 and COS-7 cells in the absence of HIV-1 Env expression. Adsorption was comparable in strength and speed to the highly specific CD4-Env interaction. CD4(-) particles exhibited only background levels of binding. Cell binding was CD4. dependent, but it was independent of the cell type from which the CD4(+) particles originated. Interestingly, CD4-dependent/Env-independent binding was only found when CD4 was present on virus particles. This suggests that the micro-environment of CD4 on virus particles uniquely expose this new cell binding activity. Its high affinity could explain in part why infection of Env(+) cells by CD4(+) particles was not detected. Further experiments will be required to evaluate whether this strong membrane interaction could represent one step in the multiple-step viral entry process.

• The Korean Journal of Physiology and Pharmacology
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• v.20 no.4
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• pp.387-397
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• 2016

Neurofibrillary tangles (NFTs) of microtubule-associated protein tau are a pathological hallmark of Alzheimer's disease (AD). Endoplasmic reticulum (ER) stress has been known to be involved in the pathogenesis of AD. However, the exact role of ER stress in tau pathology has not yet been clearly elucidated. In present study, the possible relationship between tau pathology and ER stress was examined in terms of sorcin, which is a calcium binding protein and plays an important role in calcium homeostasis. Our previous yeast two hybrid study showed that sorcin is a novel tau interacting protein. Caspase-3-cleaved tau (T4C3) showed significantly increased tau-sorcin interaction compared to wild type tau (T4). Thapsigargin-induced ER stress and co-expression of constitutively active $GSK3{\beta}$ ($GSK3{\beta}-S9A$) also exhibited significantly increased tau-sorcin interactions. T4C3-expressing cells showed potentiated thapsigargin -induced apoptosis and disruption of intracellular calcium homeostasis compared to T4-expressing cells. Overexpression of sorcin significantly attenuated thapsigargin-induced apoptosis and disruption of calcium homeostasis. In contrary, siRNA-mediated knock-down of sorcin showed significantly increased thapsigargin-induced apoptosis and disruption of calcium homeostasis. These data strongly suggest that sequestration of sorcin by aberrant forms of tau compromises the function of sorcin, such as calcium homeostasis and cellular resistance by ER stress, which may consequently result in the contribution to the progression of AD.

• Journal of Integrative Natural Science
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• v.4 no.2
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• pp.113-120
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• 2011

Brassinosteroids (BRs) are plant steroid hormones that play essential roles in growth and development. Mutations in BR-signaling pathways cause defective in growth and development like dwarfism, male sterility, abnormal vascular development and photomorphogenesis. Transition from vegetative to reproductive growth is a critical phase change in the development of a flowering plant. In a screen of activation-tagged Arabidopsis, we identified a mutant named abz126 that displayed longer hypocotyls when grown in the dark on MS media containing brassinazole (Brz), an inhibitor of BRs biosynthesis. We have cloned the mutant locus using adapter ligation PCR walking and identified that a single T-DNA had been integrated into the ninth exon of the GIGANTEA (GI) gene, involved in controling flowering time. This insertion resulted in loss-of-function of the GI gene and caused the following phenotypes: long petioles, tall plant height, many rosette leaves and late flowering. RT-PCR assays on abz126 mutant showed that the T-DNA insertion in GIGANTEA led to the loss of mRNA expression of the GI gene. In the hormone dose response assay, abz126 mutant showed: 1) an insensitivity to paclobutrazole (PAC), 2) an altered response with 6-benzylaminopurine (BAP) and 3) insensitive to Brassinolide (BL). Based on these results, we propose that the late flowering and tall phenotypes displayed by the abz126 mutant are caused by a loss-of-function of the GI gene associated with brassinosteroid hormone signaling.

• Korean Journal of Microbiology
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• v.26 no.4
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• pp.305-311
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• 1988

The spectinomycin resistant strain of slow growing R. japonicum R-168 was selected to be participated in conjugation with E. coli WA803/pGS9. Tn5 was introduced from suicide vector pGS9 into R. japonicum R-168 $spr^{r}$ chromosome at the frequency of $1.0\times 10^{-5}-5.0\times 10^{-7}$ and the transconjugante were selected on the yeast extract-mannitol plate containing kanamycin ($50{\mu}$g/ml) and spectinomycin ($100{\mu}$g/ml) after 8-9 days incubation. All transconjugants we tested were found to contain Tn 5 DNA on their genome, which was confirmed by Southern hybridization experiments. R. japonicum RNa75, which had been selected through plant test, was found to be defective in symbiotic nitrogen fixing ability and the production of leghemoglobin in soybean nodules formed by the inoculation of this mutant. In addition, this mutant strain hardly developed nitrogenase activity asymbiotically in contrast with the wild type strain, indicating that some nitrogen fixing gene might be blocked in this strain and the production of leghemoglobin could be decreased by the interference in nitrogen fixing genes.