• 한국독성학회:학술대회논문집
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• 한국독성학회 2001년도 International Symposium on Signal transduction in Toxicology
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• pp.144-144
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• 2001

Inappropriate up-regulation of cyclooxygenase-2 (COX-2) has been implicated for pathogenesis of various types of human cancer. COX-2 expression is known to be regulated by the eukaryotic transcription factor NF-$textsc{k}$B. In an attempt to link the NF-$textsc{k}$B activation and COX-2 induction, we have examined the kinetics of phorbol ester-induced activation of NF-$textsc{k}$B and COX-2 expression in the immortalized human breast epithelial cell line (MCF10A).(omitted)

• The Korean Journal of Physiology and Pharmacology
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• 제17권1호
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• pp.31-36
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• 2013

The present study was undertaken to investigate the influence of eupatilin on vascular smooth muscle contractility and to determine the mechanism involved. Denuded aortic rings from male rats were used and isometric contractions were recorded and combined with molecular experiments. Eupatilin more significantly relaxed fluoride-induced vascular contraction than thromboxane $A_2$ or phorbol ester-induced contraction suggesting as a possible anti-hypertensive on the agonist-induced vascular contraction regardless of endothelial nitric oxide synthesis. Furthermore, eupatilin significantly inhibited fluoride-induced increases in pMYPT1 levels. On the other hand, it didn't significantly inhibit phorbol ester-induced increases in pERK1/2 levels suggesting the mechanism involving the primarily inhibition of Rho-kinase activity and the subsequent phosphorylation of MYPT1. This study provides evidence regarding the mechanism underlying the relaxation effect of eupatilin on agonist-induced vascular contraction regardless of endothelial function.

• 약학회지
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• 제58권5호
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• pp.337-342
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• 2014

The present study was undertaken to investigate the influence of diosgenin on vascular smooth muscle contractility and to determine the mechanism involved. We hypothesized that diosgenin, the primary ingredient of Dioscorea villosa, plays a role in vascular relaxation through inhibition of Rho-kinase in rat aortae. Denuded arterial rings from male Sprague-Dawley rats were used and isometric tensions were recorded using a computerized data acquisition system. Interestingly, diosgenin inhibited fluoride-induced contraction but didn't inhibit phorbol ester-induced contraction suggesting that additional pathways different from endothelial nitric oxide synthesis such as inhibition of Rho-kinase might be involved in the vasorelaxation. Furthermore, diosgenin didn't inhibit thromboxane $A_2$-induced increases in pERK1/2 levels suggesting the mechanism excluding inhibition of thromboxane $A_2$-induced increases in ERK1/2 phosphorylation. This study provides evidence that diosgenin induces vascular relaxation through inhibition of Rho-kinase in rat aortae.

• 대한약학회:학술대회논문집
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• 대한약학회 2002년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.1
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• pp.100.2-101
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• 2002

• Biomolecules & Therapeutics
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• 제26권2호
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• pp.139-145
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• 2018

The present study was undertaken to investigate the influence of hypothermia on endothelium-independent vascular smooth muscle contractility and to determine the mechanism underlying the relaxation. Denuded aortic rings from male rats were used and isometric contractions were recorded and combined with molecular experiments. Hypothermia significantly inhibited fluoride-, thromboxane $A_{2-}$, phenylephrine-, and phorbol ester-induced vascular contractions regardless of endothelial nitric oxide synthesis, suggesting that another pathway had a direct effect on vascular smooth muscle. Hypothermia significantly inhibited the fluoride-induced increase in pMYPT1 level and phorbol ester-induced increase in pERK1/2 level, suggesting inhibition of Rho-kinase and MEK activity and subsequent phosphorylation of MYPT1 and ERK1/2. These results suggest that the relaxing effect of moderate hypothermia on agonist-induced vascular contraction regardless of endothelial function involves inhibition of Rho-kinase and MEK activities.

• Molecules and Cells
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• 제23권2호
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• pp.175-181
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• 2007

The present study was undertaken to determine whether $SM22{\alpha}$ participates in the regulation of vascular smooth muscle contractility using $SM22{\alpha}$ knockout mice and, if so, to investigate the mechanisms involved. Aortic ring preparations were mounted and equilibrated in organ baths for 60 min before observing contractile responses to 50 mM KCl, and then exposed to contractile agents such as phenylephrine and phorbol ester. Measurement of isometric contractions using a computerized data acquisition system was combined with molecular or cellular experiments. Interestingly, the aortas from $SM22{\alpha}$-deficient mice ($SM22^{-/-LacZ}$) displayed an almost three-fold increase in the level of $SM22{\beta}$ protein compared to wild-type mice, but no change in the levels of caldesmon, actin, desmin or calponin. $Ca^{2+}$-independent contraction in response to phenylephrine or phorbol ester was significantly decreased in the $SM22{\alpha}$-deficient mice, whereas in the presence of $Ca^{2+}$ neither contraction nor subcellular translocation of myosin light chain kinase (MLCK) in response to phenylephrine or 50 mM KCl was significantly affected. A decrease in phosphorylation of extracellular signal regulated kinase (ERK) 1/2 was observed in the $SM22{\alpha}$-deficient mice and this may be related to the decreased vascular contractility. Taken together, this study provides evidence for a pivotal role of $SM22{\alpha}$ in the regulation of $Ca^{2+}$-independent vascular contractility.

• BMB Reports
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• 제38권6호
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• pp.639-645
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• 2005

Protein kinase C (PKC) isozymes, a family of serine-threonine kinases, are important regulators of cell proliferation and malignant transformation. Phorbol esters, the prototype PKC activators, cause PKC translocation to the plasma membrane in prostate cancer cells, and trigger an apoptotic response. Studies in recent years have determined that each member of the PKC family exerts different effects on apoptotic or survival pathways. $PKC{\delta}$, one of the novel PKCs, is a key player of the apoptotic response via the activation of the p38 MAPK pathway. Studies using RNAi revealed that depletion of $PKC{\delta}$ totally abolishes the apoptotic effect of the phorbol ester PMA. Activation of the classical $PKC{\alpha}$ promotes the dephosphorylation and inactivation of the survival kinase Akt. Studies have assigned a pro-survival role to $PKC{\varepsilon}$, but the function of this PKC isozyme remains controversial. Recently, it has been determined that the PKC apoptotic effect in androgen-dependent prostate cancer cells is mediated by the autocrine secretion of death factors. $PKC{\delta}$ stimulates the release of $TNF{\alpha}$ from the plasma membrane, and blockade of $TNF{\alpha}$ secretion or $TNF{\alpha}$ receptors abrogates the apoptotic response of PMA. Molecular analysis indicates the requirement of the extrinsic apoptotic cascade via the activation of death receptors and caspase-8. Dissecting the pathways downstream of PKC isozymes represents a major challenge to understanding the molecular basis of phorbol ester-induced apoptosis.

• The Korean Journal of Physiology and Pharmacology
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• 제7권6호
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• pp.363-368
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• 2003

To gain insight on the role of pro-inflammatory cytokines in the pathogenesis and treatment of rheumatoid arthritis (RA), the phorbol 12-myristate 13-acetate (PMA)-induced IL-6 gene expression and the effect of caffeic acid phenethyl ester (CAPE) on the PMA-induced IL-6 gene expression were investigated in human fibroblast-like synoviocytes (FLSs). Synovial tissue samples were obtained from rheumatoid arthritis patients, and FLSs were isolated. The cells were stimulated with PMA (100 nM) for 6 hrs to induce IL-6 gene. The cells were pretreated with CAPE (20, 50, $100{\mu}M$) prior to PMA treatment. PMA increased IL-6 RNA expression, binding activities of transcription factors ($NF-{\kappa}B$, AP-1) to IL-6 promoter, and IL-6 promoter activity. However, CAPE inhibited PMA-induced IL-6 mRNA expression in dose-dependent manner, and also inhibited the increased binding activities of transcription factors to IL-6 promoter and IL-6 promoter activity. These results suggest that CAPE might regulate PKC-mediated IL-6 expression and inflammatory reactions in RA.

• 생명과학회지
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• 제22권1호
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• pp.87-91
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• 2012

암을 유발하는 phorbol ester로 알려진 Phorbol 12-myristate 13-acetate (PMA)는 동물세포에서 신호전달 효소의 하나인 protein kinase C (PKC)를 활성화시킨다. 본 연구에서는 옥수수 일차뿌리에서 PMA가 에틸렌 생성을 통하여 굴중성 반응을 조절하는 효과를 연구하였다. PMA는 8시간 동안 $10^{-6}$ M과 $10^{-4}$ M에서 농도 의존적으로 뿌리 생장과 굴중성 반응을 촉진시켰다. 이러한 촉진 효과는 PKC의 억제제인 staurosporine (STA)에 의해 상쇄되었다. 이 결과는 굴중성 반응이 신호전달 체계에 관여하는 protein kinase C를 통하여 조절될 가능성을 제시하고 있다. 식물호르몬인 에틸렌도 뿌리 생장과 굴중성 반응에 중요한 역할을 한다고 알려져 있다. 에틸렌 생성은 $10^{-6}$ M과 $10^{-4}$ M PMA에 의하여 각각 26%와 37% 증가하였다. PMA는 또한 ACC synthase (ACS) 활성을 촉진시켰다. 또한 이 증가 효과는 STA에 의하여 상쇄되었다. 이 결과는 옥수수 뿌리에서 굴중성 반응은 에틸렌 생성을 거쳐 protein kinase를 통하여 조절될 가능성을 제시하고 있다.

• 한국환경성돌연변이발암원학회:학술대회논문집
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• 한국환경성돌연변이발암원학회 2002년도 Molecular and Cellular Response to Toxic Substances
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• pp.175-175
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• 2002