• 대한소아치과학회지
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• 제29권3호
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• pp.337-344
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• 2002

조골 세포의 분화에 중요한 역할을 하는 전사 인자인 Runx2는 그 역할은 많이 알려져 있지만, 이를 조절하는 신호 전달체계에 대해서는 많이 알려지지 않았다. 이에 본 연구에서는 조골 세포의 분화 및 증식에 영향을 미친다고 알려진 PKC 및 MAPK pathway가 Runx2에 미치는 영향을 알아보고자 하였다. PKC활성화에 따른 Runx2의 전사 활성 및 발현 양상을 관찰하기 위해 6XOSE2-C2C12 cell에 PKC 활성제를 처리하여 luciferase assay와 Northern blot analysis를 시행하였다. MAPK 활성화에 따른 Runx2의 전사 활성을 관찰하기 위해 MAPK 활성제를 6XOSE2-C2C12 cell에 처리하여 luciferase assay를 시행하였다. 두 신호 전달 체계의 활성화에 따른 골 표지 유전자의 전사 양상을 관찰하기 위해 osteocalcin과 osteopontin을 transient transfection한 C2C12 cell에 각 신호 전달 체계의 활성제를 처리하여 luciferase assay를 시행하였다. 또한 각 신호 전달 체계가 상호 작용하는지 알아보기 위하여 MAPK 억제제를 전처리하여 MAPK pathway를 차단한 1 시간 뒤 PKC 활성제를 처리하고 luciferase assay를 시행하여 Runx2의 전사 활성을 관찰하였다. 이상의 실험으로 다음과 같은 결론을 얻었다. - PKC pathway의 활성화는 Runx2의 전사 활성 및 발현을 증가시키고 이로 인해 그의 영향을 받는 골 표지 유전자 (osteopontin, osteocalcin)의 전사도 증가한다. - MAPK pathway의 활성화는 Runx2 및 골 표지 유전자 (osteopontin, osteocalcin)의 전사활성을 증가시킨다. - PKC pathway는 MAPK pathway를 경유하여 Runx2의 전사 활성을 조절한다.

• Reproductive and Developmental Biology
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• 제30권2호
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• pp.75-79
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• 2006

The developmental regulation of the preimplantation mammalian embryos is a fundamental step for preparing the implantation and it may be regulated by several autocrine and paracrine factors including platelet-activating factor. PAF improved the embryonic survival and implantation but its role during blastocyst development is still largely unknown. In this study, the effects and the possible pathway of PAF on developmental regulation of blastocyst to hatching stage were investigated. Developmental pattern in hatching embryo was a concentration-response curve showing maximal activity at 1 nM PAF, with decreasing activity at higher concentrations. $50{\mu}M$ 1-(5-isoquinolimnesulfonyl)-2-methylpiperazinme dihydrochloride (H-7), a PKC inhibitor, inhibited the progression of blastocyst to hatching embryo. In addition H-7 blocked the PAF effects on the blastocyst development. Besides tetradecanoylphorbol acetate (TPA), a PKC activator stimulated development of blastocyst to the hatching stage. These finding revealed that PAF support the blastocyst development to the hatching embryo. Also it is suggested that PAF action pathways in hatching supporting include the PKC signaling pathway.

• 대한의생명과학회지
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• 제12권3호
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• pp.249-254
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• 2006

It has been reported that liver is a very important organ to xenotransplantation. Pig is known to be a most suitable species in transplantation of human organs. However, the physiological function of pig hepatocytes is not clear elucidated. Epidermal growth factor (EGF) is known to be a mitogen in various cell systems. Thus, we examined the effect of EGF on cell proliferation and its related signal cascades in primary cultured pig hepatocytes. EGF stimulates cell proliferation in a dose (>1ng/ml) dependent manner. EGF-induced increase of $[^3H]-thymidine$ incorporation was blocked by AG 1478 ($10^{-6}M$, an EGF receptor antagonist) genistein and herbymycin A (tyrosine kinase inhibitors, $10^{-6}M$), suggesting the role of activation and tyrosine phosphorylation of EGF receptor. In addition, EGF-induced increase of $[^3H]-thymidine$ incorporation was prevented by neomycin $(10^{-4}M)$, U73122 $(10^{-5}M)$ (phospholipase C [PLC] inhibitors), staurosporine ($(10^{-8}M)$, or bisindolylmaleimide I $(10^{-6}M)$ (protein kinase C [PKC] inhibitors), suggesting the role of PLC and PKC. Moreover, EGF-induced increase of $[^3H]-thymidine$ incorporation was blocked by PD 98059 (a p44/42 mitogen activated protein kinase [MAPK] inhibitor), SB 203580 (a p38 MAPK inhibitor), and SP 600125 (a JNK inhibitor). EGF increased the translocation of PKC from cytosol to membrane fraction and activated p42/44 MAPK, p38 MAPK and JNK. In conclusion, EGF stimulates cell proliferation via PKC and MAPK in cultured pig hepatocytes.

• 대한의생명과학회지
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• 제10권3호
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• pp.203-210
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• 2004

It has been reported that glomerulosclerosis mediated by the dysfunction of mesangial cells and insulin-like growth factors (IGFs) are associated with the development of diabetic nephropathy. However, it is not yet known the effect of high glucose on IGF-I, -II secretion, IGF-I receptor, and IGFBPs expression in the mesangial cells. Thus, this study was conducted to examine the effect of high glucose on IGF system and its involvement of protein kinase C (PKC) and oxidative stress in mesangial cells. In this study, high glucose (25 mM) increased IGF-I and IGF-II secretion and mRNA expression (P<0.05), which was blocked by PKC inhibitor (staurosporine, 10/sup -8/ M) and antioxidant (N-acetyl cystein, 10/sup -5/ M). High glucose decreased IGFBP-1 and -2 expression but increased IGFBP-5 expression. These alteration of IGFBPs by high glucose was also prevented by staurosporine and NAC, suggesting the role of PKC and oxidative stress. Indeed, high glucose increased PKC activity. Furthermore, high glucose-induced increase of lipid peroxide (LPO) formation was blocked by PKC inhibitors. In conclusion, high glucose alters IGF system via PKC-oxidative pathways in mesangial cells.

• BMB Reports
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• 제31권4호
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• pp.350-354
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• 1998

To understand the role of protein kinase C (PKC) in the regulation of chondrogenesis, we examined proteins which are phosphorylated by PKC. Stage 23/24 chick embryo wing mesenchymes were micromass-cultured to induce chondrogenesis and cell extracts were phosphorylated in a condition that activates PKC. Several proteins including 63 and 66 kDa proteins were phosphorylated. The 66 kDa protein was phosphorylated only in the presence of phorbol 12-myristate 13-acetate (PMA) and phosphatidylserine CPS), and the phosphorylation was almost completely diminished by bisindolylmaleimide, a PKC inhibitor. In addition, partially purified PKC increased the phosphorylation of the 66 kDa protein. Treatment of cultures with lysophosphatidylcholine (LPC) promoted chondrogenesis and phosphorylation of 66 kDa protein, while PMA and thymeleatoxin inhibited both of the two events. Our results suggest that the 66 kDa protein is a putative substrate of PKC, and phosphorylation of the 66 kDa protein, probably by $PKC\alpha$ is required for chondrogenesis.

• BMB Reports
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• 제40권1호
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• pp.130-134
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• 2007

Haptoglobin (Hp) is a glycoprotein that is produced by hepatic cells and secreted into the circulation. While studying the physiologic functions of Hp, we found that Hp synthesized in THP-1 monocytic cells was largely retained within cells, although Hp is considered a secretory protein. To investigate the molecular mechanism on Hp secretion in THP-1 cells, in the present study, we examined the effect of protein kinase C (PKC) on Hp secretion. When several inhibitors of PKC isoforms were tested, only Rottlerin, a specific inhibitor of PKC-$\delta$, completely blocked Hp secretion from cells to culture medium. To confirm the role of PKC-$\delta$ in Hp secretion, Hp-overexpressing COS7 cells were transiently transfected with a wild-type or a dominantnegative mutant of the PKC-$\delta$ gene. Mutant PKC-$\delta$ significantly inhibited Hp secretion, whereas the wild-type gene slightly increased Hp secretion. These results demonstrate that the PKC-$\delta$ signal is involved in Hp secretion.

• The Korean Journal of Physiology and Pharmacology
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• 제5권2호
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• pp.139-146
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• 2001

L-type $Ca^{2+}$ channels play an important role in regulating cytosolic $Ca^{2+}$ and thereby regulating hormone secretions in neuroendocrine cells. Since hormone secretions are also regulated by various kinds of protein kinases, we investigated the role of some kinase activators and inhibitors in the regulation of the L-type $Ca^{2+}$ channel currents in rat pituitary $GH_3$ cells using the patch-clamp technique. Phorbol 12,13-dibutyrate (PDBu), a protein kinase C (PKC) activator, and vanadate, a protein tyrosine phosphatase (PTP) inhibitor, increased the $Ba^{2+}$ current through the L-type $Ca^{2+}$ channels. In contrast, bisindolylmaleimide I (BIM I), a PKC inhibitor, and genistein, a protein tyrosine kinase (PTK) inhibitor, suppressed the $Ba^{2+}$ currents. Forskolin, an adenylate cyclase activator, and isobutyl methylxanthine (IBMX), a non-specific phosphodiesterase inhibitor, reduced $Ba^{2+}$ currents. The above results show that the L-type $Ca^{2+}$ channels are activated by PKC and PTK, and inhibited by elevation of cyclic nucleotides such as cAMP. From these results, it is suggested that the regulation of hormone secretion by various kinase activity in $GH_3$ cells may be attributable, at least in part, to their effect on L-type $Ca^{2+}$ channels.

• BMB Reports
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• 제47권1호
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• pp.45-50
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• 2014

Aspirin has been demonstrated to be effective in inhibiting COX-2 and $PGE_2$ in Alveolar macrophages (AMs). However, the mechanisms have not been fully understood. In the present study, we found that pretreatment with aspirin inhibited LPS-induced COX-2 and$PGE_2$ upregulation, $I{\kappa}B{\alpha}$ degradation, NF-${\kappa}B$ activation and the increase of PKC activity, but elevated LPS-induced the decrease of PTP activity. The PKC inhibitor calphostin C dramatically reduced the COX-2 mRNA and $PGE_2$ levels, but the PTP inhibitor peroxovanadium (POV) significantly increased the COX-2 mRNA and$PGE_2$ levels. Furthermore, the PTP inhibitor mitigated the inhibitory effect of aspirin on COX-2 and$PGE_2$ upregulation and NF-${\kappa}B$ activation, whereas the PKC inhibitor enhanced the inhibitory effects of aspirin on the production of COX-2 and$PGE_2$. Our data indicate a novel mechanism by which aspirin acts as a potent anti-inflammatory agent in alveolus macrophages and ALI.

• 대한물리치료과학회지
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• 제13권2호
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• pp.129-135
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• 2006

Vascular smooth muscle contraction is mediated by activation of extracellular signal-regulated kinase (ERK) 1/2, an isoform of mitogen-activated protein kinase (MAPK). However, the role of stress-activated protein kinase/c-Jun N-terminal kinase (JNK) in vascular smooth muscle contraction has not been defined. We investigated the role of JNK in the contractile response to norepinephrine (NE) in rat aortic smooth muscle. NE evoked contraction in a dose-dependent manner, and this effect was inhibited by the JNK inhibitor SP600125. NE increased the phosphorylation of JNK, which was greater in aortic smooth muscle from hypertensive rats than from normotensive rats. NE-induced JNK phosphorylation was significantly inhibited by SP600125 and the conventional-type PKC (cPKC) inhibitor Go6976, but not by the Rho kinase inhibitor Y27632 or the phosphatidylinositol 3-kinase inhibitor LY294002. Thymeleatoxin, a selective activator of cPKC, increased JNK phosphorylation, which was inhibited by $G{\ddot{o}}6976$. SP600125 attenuated the phosphorylation of caldesmon, an actin-binding protein whose phosphorylation is increased by NE. These results show that JNK contributes to NE-mediated contraction through phosphorylation of caldesmon in rat aortic smooth muscle, and that this effect is regulated by the PKC pathway, especially cPKC.

• Asian Pacific Journal of Cancer Prevention
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• 제14권10호
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• pp.5687-5692
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• 2013

Type 2 diabetes mellitus (T2DM) has contributed to advanced breast cancer development over the past decades. However, the mechanism underlying this contribution is poorly understood. In this study, we determined that high glucose enhanced proteasome activity was accompanied by enhanced proliferation, migration and invasion, as well as suppressed apoptosis, in human breast cancer MCF-7 cells. Proteasome inhibitor bortezomib (BZM) pretreatment mitigated high glucose-induced MCF-7 cell growth and invasion. Furthermore, high glucose increased protein kinase C delta ($PKC{\delta}$)-phosphorylation. Administration of the specific $PKC{\delta}$ inhibitor rottlerin attenuated high glucose-stimulated cancer cell growth and invasion. In addition, $PKC{\delta}$ inhibition by both rottlerin and $PKC{\delta}$ shRNA significantly suppressed high glucose-induced proteasome activity. Our results suggest that $PKC{\delta}$-dependent ubiquitin proteasome system activation plays an important role in high glucose-induced breast cancer cell growth and metastasis.