• KSBB Journal
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• v.24 no.5
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• pp.425-431
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• 2009

Hepatocyte growth factor (HGF) and its receptor play an important role in the formation and progression of glioma. In this study, I investigated the ability of HGF to recover of the PSA siRNA-suppressed cell proliferation, migration and invasion in U-251-MG cells. PSA siRNA-transfected U-251-MG cells showed the reduction of the proliferation, migration and invasion with compared to control. Treatment of HGF on the PSA siRNA-transfected U-251-MG cells recovered the ability of proliferation, migration and invasion. These data suggest that PSA and HGF may use unique and parallel signaling cascade leading to the proliferative, migrative and invasive phenotype of U-251-MG cells. I also showed that PSA cooperated with HGF to a migrative and invasive phenotype via the increased secretion of matrix metalloproteinase-2 (MMP-2) and MMP-9.

• The Korean Journal of Physiology and Pharmacology
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• v.1 no.4
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• pp.413-423
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• 1997

The importance of the kidney in the development of hypertension was first demonstrated by Goldblatt and his colleagues more than fifty years ago. Many hormones and other regulatory factors have been proposed to play a major role in the development of hypertension. Among these factors angiotensia II (ANG II) is closely involved in renal hypertension development since it directly regulates $Na^+$ reabsorption in the renal proximal tubule. Thus the aim of the present study was to examine signaling pathways of low dose of ANC II on the $Na^+$ uptake of primary cultured rabbit renal proximal tubule cells (PTCs) in hormonally defined seum-free medium. The results were as follows: 1) $10^{-11}$ M ANG II has a significant stimulatory effect on growth as compared with control. Alkaline phosphatase exhibited significantly increased activity. However, leucine aminopeptidase and ${\gamma}-glutamyl$ transpeptidase activity were not significant as compared with control. In contrast to $10^{-11}$ M ANG II stimulated $Na^+$ uptake $(108.03{\pm}2.16% of that of control)$, $10^{-9}$ M ANG II inhibited ($92.42{\mu}2.23%$ of that of control). The stimulatory effect of ANG II on $Na^+$ uptake was amiloride-sensitive and inhibited by losartan (ANG II receptor subtype 1 antagonist) and not by PD123319 (ANG II receptor subtype 2 antagonist). 2) Pertussis toxin (PTX) alone inhibited $Na^+$ uptake by $85.52{\pm}3.52%$ of that of control. In addition, PTX pretreatment prevented the AMG II-induced stimulation of $Na^+$ uptake. 8-Bromoadenosine 3',5'-cyclic monophosphate (8-Br-cAMP), forskolin, and isobutylmethylxanthine (IBMX) alone inhibited $Na^+$ uptake by $88.79{\pm}2.56,\;80.63{\pm}4.38,\;and\;84.47{\pm}4.74%$ of that of control, respectively, and prevented the ANG II-induced stimulation of $Na^+$ uptake. However, $10^{-11}$ M ANG II did not stimulate cAMP production. 3) The addition of 12-O-te-tradecanoylphorbol-13-acetate (TPA, 0.01 ng/ml) to the PTCs produced significant increase in $Na^+$ uptake ($114.43{\pm}4.05%$ of that of control). When ANG II and TPA were added together to the PTCs, there was no additive effect on $Na^+$ uptake. Staurosporine alone had no effect on $Na^+$ uptake, but led to a complete inhibition of ANG II- or TPA-induced stimulation of Na'uptake. ANG II treatment resulted in a $111.83{\mu}4.51%$ increase in total protein kinase C (PKC) activity. In conclusion, the PTX-sensitive PKC pathway is the main signaling cascade involved in the stimulatory effects of ANG II on $Na^+$ uptake in the PTCs.

• Journal of Life Science
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• v.25 no.5
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• pp.585-593
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• 2015

Stress fiber (SF) alteration is mediated by cellular receptors, which, upon interaction with the extracellular counterpart, signal to the actin cytoskeleton for remodeling. This association is mediated by a variety of scaffold and signaling factors, which control the mechanical and signaling activities of the interaction site. The heterotrimeric transmembrane lymphotoxin α1β2 (LTα1β2), a member of the tumor necrosis factor (TNF) family of cytokines, including soluble homotrimeric lymphotoxin (LT α), plays an important role in lymphoid tissue architecture. Ligation between LTα1β2 and the lymphotoxin β receptor (LTβR) activates signal-cascade in fibroblastic reticular cells (FRCs). We found LTβR stimulation using an agonistic anti-LTβR antibody alone or combined with LTα or TNFα induced changes in the actin and plasticity of cells. To clarify the involvement of myosin underlying the alteration, we analyzed the effect of myosin light chain kinase (MLCK) with an MLCK inhibitor (ML7), the phosphorylation level of myosin light chains (MLC), and the level of phospho-myosin phosphatase target subunit 1 (MYPT1) after treatment with an agonistic anti-LTβR antibody for cytoskeleton reorganization in FRCs. The inhibition of MLCK activity induced changes in the actin cytoskeleton organization and cell morphology in FRC. In addition, we showed the phosphorylation of MLC and MYPT1 was reduced by LTβR stimulation in cells. A DNA chip revealed the LTβR stimulation of FRC down-regulated transcripts of myosin and actin components. Collectively, these results suggest LTβR stimulation is linked to myosin regarding SF alteration in FRC.

• Journal of Life Science
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• v.25 no.5
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• pp.607-614
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• 2015

Cancers are the largest cause of mortality and morbidity all over the world. Cordycepin, an adenosine analog, is a major functional component of the Cordyceps species, which has been widely used in traditional Oriental medicine. Over the last decade, this compound has been reported to possess many pharmacological properties, such as an ability to enhance immune function, as well as anti-inflammatory, antioxidant and anti-cancer effects. Recently, numerous studies have reported interesting properties of cordycepin as a chemopreventive agent as well. There is an accumulating body of experimental evidences suggesting that cordycepin impedes cancer progression by promoting apoptosis, inducing cell cycle arrest, modulating intracellular signaling pathways, and inhibiting invasion and metastasis of cancer cells. In many cancer cell lines, cordycepin inhibits growth and cell cycle progression by inducing arrest of the G2/M phase, resulting from the inhibition of retinoblastoma protein phosphorylation and induction of cyclin-dependent kinase inhibitors. To induce apoptosis, cordycepin activates the extrinsic and intrinsic pathways, which promotes reactive oxygen species generation and the downstream activation of kinase cascades. Cordycepin also can activate alternative pathways to cell death such autophagy. In addition, cordycepin can inhibit the pro-metastatic processes of cancer cell detachment, migration, and invasion through a variety of mechanisms, including the nuclear factor-kappa B and activated protein-1 signaling pathways. In this review, we summarized the variety of action mechanisms by which cordycepin may mediate chemopreventive effects on cancer and discussed the potential of this natural product as a promising therapeutic inhibitor of cancer development.

• Journal of Life Science
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• v.23 no.7
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• pp.926-932
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• 2013

Glutamine and serum are essential for cell survival and proliferation in vitro, yet the signaling pathways that sense glutamine and serum levels in endothelial cells remain uninvestigated. In this study, we examined the effects of glutamine deprivation and serum starvation on the fate of endothelial cells using a human umbilical vein endothelial cell (HUVEC) model. Our data indicated that glutamine deprivation and serum starvation trigger a progressive reduction in cell viability through apoptosis induction in HUVECs as determined by DAPI staining and flow cytometry analysis. Although the apoptotic effects were more predominant in the glutamine deprivation condition, both apoptotic actions were associated with an increase in the Bax/Bcl-2 (or Bcl-xL) ratio, down-regulation of the inhibitor of apoptosis protein (IAP) family proteins, activation of caspase activities, and concomitant degradation of poly (ADP-ribose) polymerases. Moreover, down-regulation of the expression of Bid or up-regulation of truncated Bid (tBid) were observed in cells grown under the same conditions, indicating that glutamine deprivation and serum starvation induce the apoptosis of HUVECs through a signaling cascade involving death-receptor-mediated extrinsic pathways, as well as mitochondria-mediated intrinsic caspase pathways. However, apoptosis was not induced in cells grown in glutamine- and serum-free media when compared with cells exposed to glutamine deprivation or serum starvation alone. Taken together, our data indicate that glutamine deprivation and serum starvation suppress cell viability without apoptosis induction in HUVECs.

• Biomolecules & Therapeutics
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• v.22 no.6
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• pp.510-518
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• 2014

Chronic (>24 h) exposure of arsenite, an environmental toxicant, has shown the decreased nitric oxide (NO) production in endothelial cells (EC) by decreasing endothelial NO synthase (eNOS) expression and/or its phosphorylation at serine 1179 ($eNOS-Ser^{1179}$ in bovine sequence), which is associated with increased risk of vascular diseases. Here, we investigated the acute (<24 h) effect of arsenite on NO production using bovine aortic EC (BAEC). Arsenite acutely increased the phosphorylation of $eNOS-Thr^{497}$, but not of $eNOS-Ser^{116}$ or $eNOS-Ser^{1179}$, which was accompanied by decreased NO production. The level of eNOS expression was unaltered under this condition. Treatment with arsenite also induced reactive oxygen species (ROS) production, and pretreatment with a ROS scavenger N-acetyl-L-cysteine (NAC) completely reversed the observed effect of arsenite on $eNOS-Thr^{497}$ phosphorylation. Although protein kinase C (PKC) and protein phosphatase 1 (PP1) were reported to be involved in $eNOS-Thr^{497}$ phosphorylation, treatment with PKC inhibitor, Ro318425, and overexpression of various PKC isoforms did not affect the arsenite-stimulated $eNOS-Thr^{497}$ phosphorylation. In contrast, treatment with PP1 inhibitor, calyculin A, mimicked the observed effect of arsenite on $eNOS-Thr^{497}$ phosphorylation. Lastly, we found decreased cellular PP1 activity in arsenite-treated cells, which was reversed by NAC. Overall, our study demonstrates firstly that arsenite acutely decreases NO production at least in part by increasing $eNOS-Thr^{497}$ phosphorylation via ROS-PP1 signaling pathway, which provide the molecular mechanism underlying arsenite-induced increase in vascular disease.

• The Plant Pathology Journal
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• v.21 no.2
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• pp.149-157
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• 2005

A novel rice (Oryza sativa L.) gene, homologous to Arabidopsis pathogenesis-related NDR1 gene, was cloned from cDNA library prepared from 30 min Magnaporthe grisea -treated rice seedling leaves, and named as OsNDR1. OsNDR1 encoded a 220-aminoacid polypeptide and was highly similar to the Arabidopsis AtNDR1 protein. OsNDR1 is a plasma membrane (PM)-localized protein, and presumes through sequence analysis and protein localization experiment. Overexpression of OsNDR1 promotes the expression of PBZ1 that is essential for the activation of defense/stressrelated gene. The OsNDR1 promoter did not respond significantly to treatments with either SA, PBZ, or ETP. Exogenously applied BTH induces the same set of SAR genes as biological induction, providing further evidence for BTH as a signal. Presumably, BTH is bound by a receptor and the binding triggers a signal transduction cascade that has an ultimate effect on transcription factors that regulate SAR gene expression. Thus OsNDR1 may act as a transducer of pathogen signals and/or interact with the pathogen and is indeed another important step in clarifying the component participating in the defense response pathways in rice.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.4
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• pp.499-509
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• 2008

Foxo1 plays an important role in the integration of hormone-activated signaling pathways with the complex transcriptional cascade that promotes preadipocyte differentiation of clonal cell lines from rodents. We isolated the full-length cDNA of porcine FoxO1 gene using RACE, confirmed by visual Northern blotting. The deduced amino acids indicated 94% and 90% identities with the corresponding human and mice aa. Analysis of the aa sequence, showed that it included a Forkhead domain (aa 167-247), a transmembrane structure domain (aa 90-113), a LXXLL motif (aa 469-473), and 51 Ser, 8 Thr, and 4 Tyr phosphorylation sites, indicating a potential important role for FoxO1 transcriptional activity in vivo. Using the IMpRH panel, we mapped FoxO1 gene to chromosome 11p13. Our data provide basic molecular information useful for the further investigation on the function of FoxO1 gene. Time-course analysis of FoxO1 expressions indicated that levels of mRNA and protein gradually increased from day 0 to 3, and it reached almost maximal level at day 3, then decreased from day 5 to 7 in porcine primary preadipocyte differentiation. After induction by IGF-1, GPDH activity and accumulation of lipid increased, however, expressions of FoxO1 mRNA and protein were inhibited in a dose dependent manner. These results suggest that FoxO1 takes part in porcine preadipocyte differentiation and expressions of FoxO1 were regulated by IGF-1.

• Molecules and Cells
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• v.41 no.4
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• pp.362-372
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• 2018

High mobility group box 2 (HMGB2) is an abundant, chromatin-associated, non-histone protein involved in transcription, chromatin remodeling, and recombination. Recently, the HMGB2 gene was found to be significantly downregulated during senescence and shown to regulate the expression of senescent-associated secretory proteins. Here, we demonstrate that HMGB2 transcription is repressed by p21 during radiation-induced senescence through the ATM-p53-p21 DNA damage signaling cascade. The loss of p21 abolished the downregulation of HMGB2 caused by ionizing radiation, and the conditional induction of p21 was sufficient to repress the transcription of HMGB2. We also showed that the p21 protein binds to the HMGB2 promoter region, leading to sequestration of RNA polymerase and transcription factors E2F1, Sp1, and p300. In contrast, NF-Y, a CCAAT box-binding protein complex, is required for the expression of HMGB2, but NF-Y binding to the HMGB2 promoter was unaffected by either radiation or p21 induction. A proximity ligation assay results confirmed that the chromosome binding of E2F1 and Sp1 was inhibited by p21 induction. As HMGB2 have been shown to regulate premature senescence by IR, targeting the p21-mediated repression of HMGB2 could be a strategy to overcome the detrimental effects of radiation-induced senescence.

• International Journal of Industrial Entomology and Biomaterials
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• v.37 no.1
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• pp.21-28
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• 2018

CRISPR/Cas9 gene editing system is an efficient method to mutation in a sequence specific manner. Here we report the direct transfection of the Cas9 nuclease and gene specific guide RNA can be used in BM-N cell line derived from Bombyx mori ovarian tissue to enfeeble function of endogenous gene in vitro. We have used gene editing system to negative regulation components of major signaling cascade, the Toll pathway, which controls B. mori resistance to microbe infections, such as fungi and gram positive bacteria. We demonstrate that the $I{\kappa}B-like$ protein Cactus may controls the activation of transcription factors such as Rel A and Rel B. The direct transfection of Cas9 nuclease and Cactus-specific guide-RNA complex may be used in BM-N cells to disrupt the function of endogenous genes in vitro. A mutation frequency of 30-40% was observed in the transfected cells, and various mutations caused the target region. Moreover, RT-PCR analysis revealed that Cactus gene was down regulated after these mutations. More importantly, mutation of BmCactus stimulated expression of lysozyme, moricin, and lebocin genes. These results suggest that the CRISPR/Cas9 systems are expected to efficiently induce site-specific mutations and it was possible to produce antimicrobial peptide through the gene editing.