Jeong-Hyung Lee

Kangwon National University, Shunsen, Gangwon-do, South Korea

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Publications (55)209.04 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Homoisoflavonoids constitute a small class of natural products. In the present study, we investigated the anti-inflammatory effect of sappanone A (SPNA), a homoisoflavanone that is isolated from the heartwood of Caesalpinia sappan (Leguminosae), in murine macrophages. SPNA inhibited the production of nitric oxide (NO), prostaglandin E2 (PGE2) and interleukin-6 (IL-6) as well as the expression of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2) and IL-6 in lipopolysaccharide (LPS)-stimulated RAW264.7 cells. Moreover, SPNA protected C57BL/6 mice from LPS-induced mortality. Treatment of RAW264.7 cells with SPNA induced heme oxygenase (HO)-1 protein and mRNA expression and increased nuclear translocation of the nuclear factor-E2-related factor 2 (Nrf2) as well as the expression of Nrf2 target genes such as NAD(P)H:quinone oxidoreductase 1 (NQO1). Knockdown of Nrf2 by siRNA blocked SPNA-mediated HO-1 induction. SB203580, p38 mitogen-activated protein kinase (MAPK) inhibitor, blocked SPNA-induced HO-1 expression and nuclear translocation of Nrf2, suggesting that SPNA induces HO-1 expression by activating Nrf2 through the p38 MAPK pathway. Consistent with the notion that the Nrf2/HO-1 pathway has anti-inflammatory properties, inhibiting HO-1 significantly abrogated the anti-inflammatory effects of SPNA in LPS-stimulated RAW264.7 cells. Moreover, SPNA suppressed LPS-induced nuclear factor κB (NF-κB) activation via inhibiting Ser 536 phosphorylation and transcriptional activity of RelA/p65 subunit of NF-κB. Taken together, these findings suggest that SPNA exerts its anti-inflammatory effect by modulating the Nrf2 and NF-κB pathways, and may be a valuable compound to prevent or treat inflammatory diseases. Copyright © 2015. Published by Elsevier B.V.
    International immunopharmacology 09/2015; 28(1):328-336. DOI:10.1016/j.intimp.2015.06.015 · 2.71 Impact Factor
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    ABSTRACT: Eurycoma longifolia is an herbal medicinal plant popularly used in Southeast Asian countries. In the present study, we show that 7-methoxy-(9H-β-carbolin-1-il)-(E)-2-propenoic acid (7-MCPA), a β-carboline alkaloid isolated from E. longifolia, exerted anti-inflammatory effects by activating the nuclear factor-E2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) pathway. 7-MCPA inhibited lipopolysaccharide (LPS)-induced production of nitric oxide (NO), prostaglandin E2 (PGE2 ), and interleukin-6 (IL-6) in RAW264.7 cells and rescued C57BL/6 mice from LPS-induced lethality in vivo. LPS-induced expression of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and IL-6 was also significantly suppressed by treatment of 7-MCPA in RAW264.7 cells. 7-MCPA induced nuclear translocation of Nrf2 and increased transcription of its target genes, such as HO-1. Treating RAW264.7 cells with 7-MCPA increased the intracellular level of reactive oxygen species (ROS) and the phosphorylation level of p38 mitogen-activated protein kinase (MAPK); however, co-treatment with the antioxidant N-acetyl-cysteine (NAC) blocked 7-MCPA-induced p38 MAPK phosphorylation. Moreover, NAC or SB203580 (p38 MAPK inhibitor) blocked 7-MCPA-induced nuclear translocation of Nrf2, suggesting that 7-MCPA activated Nrf2 via a ROS-dependent p38 pathway. 7-MCPA induced HO-1 protein and mRNA expression and knockdown of Nrf2 with siRNA or SB203580 blocked 7-MCPA-mediated induction of HO-1 expression. Inhibiting Nrf2 or HO-1 abrogated the anti-inflammatory effects of 7-MCPA in LPS-stimulated RAW264.7 cells. We also demonstrated that 7-MCPA suppressed LPS-induced nuclear factor κB (NF-κB) activation. These results provide the first evidence that 7-MCPA exerts its anti-inflammatory effect by modulating the Nrf2 and NF-κB pathways and may be a potential Nrf2 activator to prevent or treat inflammatory diseases. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.
    Journal of Cellular Biochemistry 08/2015; DOI:10.1002/jcb.25315 · 3.37 Impact Factor
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    ABSTRACT: The human CD99 protein is a 32-kDa type I transmembrane glycoprotein, while CD98 is a disulfide-linked 125-kDa heterodimeric type II transmembrane glycoprotein. It has been previously shown that CD99 and CD98 oppositely regulate β1 integrin signaling, though the mechanisms by which this regulation occurs are not known. Our results revealed that antibody-mediated crosslinking of CD98 induced FAK phosphorylation at Y397 and facilitated the formation of the protein kinase Cα (PKCα)-syntenin-focal adhesion kinase (FAK), focal adhesions (FAs), and IPP-Akt1-syntenin complex, which mediates β1 integrin signaling. In contrast, crosslinking of CD99 disrupted the formation of the PKCα-syntenin-FAK complex as well as FA via FAK dephosphorylation. The CD99-induced dephosphorylation of FAK was apparently mediated by the recruitment of Src homology region 2 domain-containing phosphatase-2 (SHP2) to the plasma membrane and subsequent activation of its phosphatase activity. Further consequences of the activation of SHP2 included the disruption of FAK-talin and talin-β1 integrin interactions and attenuation in the formation of the IPP-Akt1-syntenin complex at the plasma membrane, which resulted in reduced cell-ECM adhesion. This report uncovers the molecular mechanisms underlying the inverse regulation of β1 integrin signaling by CD99 and CD98 and may provide a novel therapeutic approach to treat inflammation and cancer. Copyright © 2015. Published by Elsevier Inc.
    Experimental Cell Research 07/2015; DOI:10.1016/j.yexcr.2015.07.010 · 3.37 Impact Factor
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    ABSTRACT: Two new lanostane triterpenes, 3α,12β,15α-triacetoxy-5α-lanosta-7,9(11),24-trien-26-oic acid (1) and 5α-lanosta-8,24-diene-26,27-dihydroxy-3,7-dione (2), together with sixteen known compounds (3–18) were isolated from the fruiting bodies of the Vietnamese mushroom Ganoderma lucidum. Their chemical structures were determined by extensive spectroscopic (IR, HR-EI-MS, 1D and 2D NMR) analyses. Potential cytotoxic activities of these compounds were evaluated against human non-small cell lung adenocarcinoma (A549), breast adenocarcinoma (MCF-7), and prostatic small cell carcinoma (PC-3). Among the compounds, 3α,12β,15α-triacetoxy-5α-lanosta-7,9(11),24-trien-26-oic acid (1) showed significant cytotoxic activity against PC-3 cells with an IC50 of 11.5 μM. In studies of anti-angiogenesis activity, ganoderic acid F (17) was found to have the most potent inhibitory effect on the formation of capillary-like structures of human umbilical vein endothelial cells.
    Phytochemistry Letters 06/2015; 12:69-74. DOI:10.1016/j.phytol.2015.02.012 · 1.54 Impact Factor
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    ABSTRACT: Metastasis is the primary cause of cancer-associated mortality. The ternary IPP complex of integrin-linked kinase, PINCH and parvin functions as a signaling platform for integrins, which modulate numerous cellular processes including cell migration and invasion. Chelidonine, isolated from Chelidonium majus, is a benzophenanthridine alkaloid that exhibits anticancer properties; however, the anti‑migratory and anti‑invasive effects of chelidonine remain unknown. The aim of the present study was to investigate the inhibitory effects of chelidonine on migration and invasion of MDA‑MB‑231 human breast cancer cells, and to determine the underlying mechanisms. Chelidonine was shown to inhibit the migration and invasion of MDA‑MB‑231 cells in a concentration‑dependent manner, without affecting the cell viability. Chelidonine did not significantly inhibit the adhesion of the cells to type 1 collagen (COL‑I), however it did affect cell spreading and reorganization of the actin cytoskeleton. Chelidonine also inhibited COL‑I‑induced protein kinase B (Akt) activation and translocation to the plasma membrane, however, it did not significantly inhibit the activation of focal adhesion kinase. Notably, chelidonine treatment significantly inhibited COL‑I‑induced formation of the IPP complex and activation of IPP downstream signaling molecules, such as extracellular signal‑regulated kinase (ERK)1/2. These results suggest that chelidonine exhibits anti‑migratory and anti‑invasive effects in MDA‑MB‑231 cells, by suppressing COL‑I‑induced integrin signaling, through inhibiting the formation of the IPP complex and subsequent down‑regulation of IPP downstream signaling molecules, such as Akt and ERK1/2. These results suggest that chelidonine may be a potential therapeutic agent against metastasis of invasive human cancer cells.
    Molecular Medicine Reports 04/2015; DOI:10.3892/mmr.2015.3621 · 1.48 Impact Factor
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    ABSTRACT: Sorghum contains diverse pharmacologically active phytochemicals including tannins, phenolic acids and anthocyanins. In the present study, we show that caffeoylglycolic acid methyl ester (CGME), a major constituent of the grains of Sorghum bicolor, exerted the anti-inflammatory effects by inducing HO-1 expression. Treatment of RAW264.7 cells with CGME induced HO-1 protein and mRNA expression. CGME increased nuclear translocation of nuclear factor-E2-related factor 2 (Nrf2) and knockdown of Nfr2 by siRNA blocked CGME-mediated HO-1 induction. SP600125 (a JNK inhibitor) or LY294002 (a PI3K inhibitor) blocked CGME-induced HO-1 expression and nuclear translocation of Nrf2, suggesting that CGME induces HO-1 expression via activating Nfr2 through PI3K and JNK pathway. Consistent with the notion that HO-1 has anti-inflammatory properties, CGME inhibited the production of nitric oxide (NO), prostaglandin E2 (PGE2) and interleukin-6 (IL-6) as well as the expression of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2) and IL-6 in lipopolysaccharide (LPS)-stimulated RAW264.7 cells. CGME also protected C57BL/6 mice from LPS-induced mortality. However, inhibition of HO-1 abrogated the inhibitory effects of CGME on the production of NO, COX-2 and IL-6 in LPS-stimulated RAW264.7 cells. Taken together, these findings suggest that CGME exerts an anti-inflammatory effect through the Nrf2/HO-1 pathway, and may be a potential HO-1 inducer for preventing or treating inflammatory diseases.
    RSC Advances 02/2015; 5(23). DOI:10.1039/C4RA13847C · 3.84 Impact Factor
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    ABSTRACT: IL-32β is highly expressed and increases the migration and invasion of gastric, lung, and breast cancer cells. Since IL-32 enhances VEGF production under hypoxic conditions, whether IL-32β is regulated by hypoxia was examined. Hypoxic conditions and a mimetic chemical CoCl2 enhanced IL-32β production. When cells were treated with various inhibitors of ROS generation to prevent hypoxia-induced ROS function, IL-32β production was suppressed by both NADPH oxidase and mitochondrial ROS inhibitors. IL-32β translocated to the mitochondria under hypoxic conditions, where it was associated with mitochondrial biogenesis. Thus, whether hypoxia-induced IL-32β is associated with oxidative phosphorylation (OXPHOS) or glycolysis was examined. Glycolysis under aerobic and anaerobic conditions is impaired in IL-32β-depleted cells, and the hypoxia-induced IL-32β increased glycolysis through activation of lactate dehydrogenase. Src is also known to increase lactate dehydrogenase activity, and the hypoxia-induced IL-32β was found to stimulate Src activation by inhibiting the dephosphorylation of Src. These findings revealed that a hypoxia-ROS-IL-32β-Src-glycolysis pathway is associated with the regulation of cancer cell metabolism. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.
    Cancer Letters 11/2014; 356(2). DOI:10.1016/j.canlet.2014.10.030 · 5.62 Impact Factor
  • Okhwa Kim · Cheol Hwangbo · Nara Tae · Suhyun Lee · Jeong-Hyung Lee
    Cancer Research 10/2014; 74(19 Supplement):1055-1055. DOI:10.1158/1538-7445.AM2014-1055 · 9.28 Impact Factor
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    ABSTRACT: Ganoderma lucidum is a popular medicinal mushroom used in traditional medicine for preventing or treating a variety of diseases. In the present study, we investigated the anti-inflammatory and heme oxygenase (HO)-1 inducing effects of 12 lanostane triterpenes from G. lucidum in RAW264.7 cells. Of these, seven triterpenes, butyl lucidenateE2, butyl lucidenateD2 (GT-2), butyl lucidenate P, butyl lucidenateQ, Ganoderiol F, methyl ganodenate J and butyl lucidenate N induced HO-1 expression and suppressed lipopolysaccharide (LPS)-induced nitric oxide (NO) production. Inhibiting HO-1 activity abrogated the inhibitory effects of these triterpenes on the production of NO in LPS-stimulated RAW264.7 cells, suggesting the involvement of HO-1 in the anti-inflammatory effects of these triterpenes. We further studied the anti-inflammatory and HO-1 inducing effects of GT-2. Mitogen-activated protein kinase inhibitors or N-acetylcysteine, an antioxidant, did not suppress GT-2-mediated HO-1 induction; however, LY294002, a phosphoinositide 3-kinase (PI3K) inhibitor, blocked GT-2-induced HO-1 mRNA and protein expression. GT-2 increased nuclear translocation of nuclear factor-E2-related factor 2 (Nrf2) and knockdown of Nrf2 by small interfering RNA blocked GT-2-mediated HO-1 induction, suggesting that GT-2 induced HO-1 expression via the PI3K/AKT-Nrf2 pathway. Consistent with the notion that HO-1 has anti-inflammatory properties, GT-2 inhibited the production of tumor necrosis factor-α and interleukin-6, as well as inducible nitric oxide synthase and cyclooxygenase-2 expression. These findings suggest that HO-1 inducing activities of these lanostane triterpenes may be important in the understanding of a novel mechanism for the anti-inflammatory activity of G. lucidum.
    Toxicology and Applied Pharmacology 09/2014; 280(3). DOI:10.1016/j.taap.2014.09.007 · 3.63 Impact Factor
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    ABSTRACT: 3-Deoxysappanchalcone (3-DSC), isolated from Caesalpinia sappan (Leguminosae), is a chalcone that exerts a variety of pharmacological activities. In the present study, we demonstrated that 3-DSC exerts anti-inflammatory activity in murine macrophages by inducing heme oxygenase-1 (HO-1) expression at the translational level. Treatment of RAW264.7 cells with 3-DSC induced HO-1 protein expression in a dose- and time-dependent manner without affecting HO-1 mRNA expression. Mitogen-activated protein kinase inhibitors or actinomycin D, a transcriptional inhibitor, did not block 3-DSC-mediated HO-1 induction. However, 3-DSC-mediated HO-1 induction was completely blocked by treatment with cycloheximide, a translational inhibitor, or rapamycin, an inhibitor of the mammalian target of rapamycin (mTOR). Strikingly, 3-DSC increased the phosphorylation level of mTOR downstream target molecules such as eukaryotic translation initiation factor 4E-binding protein 1 (4E-BP1) and S6 kinase 1 (S6K1), as well as AKT in a dose- and time-dependent manner, suggesting that the 3-DSC induces HO-1 expression by activating the AKT/mTOR pathway. Consistent with the notion that HO-1 has anti-inflammatory properties, 3-DSC inhibited the production of nitric oxide (NO) and interleukin (IL)-6 in lipopolysaccharide (LPS)-stimulated RAW264.7 cells. Inhibition of HO-1 activity by treatment with tin protoporphyrin IX, a specific HO-1 inhibitor, abrogated the inhibitory effects of 3-DSC on the production of NO and IL-6 in LPS-stimulated RAW264.7 cells. Taken together, 3-DSC may be an effective HO-1 inducer at the translational level that has anti-inflammatory effects, and a valuable compound for modulating inflammatory conditions.
    International Immunopharmacology 08/2014; 22(2). DOI:10.1016/j.intimp.2014.07.025 · 2.71 Impact Factor
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    Namho Kim · Cheol Hwangbo · Suhyun Lee · Jeong-Hyung Lee
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    ABSTRACT: The abnormal proliferation and migration of vascular smooth muscle cell (VSMC) contributes importantly to the pathogenesis of atherosclerosis and restenosis. Here, we investigated the effects of eupatolide (EuTL), a sesquiterpene lactone isolated from the medicinal plant Inula britannica, on platelet-derived growth factor (PDGF)-induced proliferation and migration of primary rat aortic smooth muscle cells (RASMCs), as well as its underlying mechanisms. EuTL remarkably inhibited PDGF-induced proliferation and migration of RASMCs. Treatment of RASMCs with EuTL induced both protein and mRNA expression of heme oxygenase-1 (HO-1). SB203580 (a p38 inhibitor), SP600125 (a JNK inhibitor), U0126 (a MEK inhibitor) and LY294002 (a PI3K inhibitor) did not suppress EuTL-induced HO-1 expression; however, N-acetylcysteine (NAC, an antioxidant) blocked EuTL-induced HO-1 expression. Moreover, treatment of RASMCs with EuTL increased reactive oxygen species (ROS) accumulation and nuclear translocation of nuclear factor-E2-related factor 2 (Nrf2); however, this translocation was also inhibited by NAC. NAC or inhibition of HO-1 significantly attenuated the inhibitory effects of EuTL on PDGF-induced proliferation and migration of RASMCs. Taken together, these findings suggest that EuTL could suppress PDGF-induced proliferation and migration of VSMCs through HO-1 induction via ROS-Nrf2 pathway and may be a potential HO-1 inducer for preventing or treating vascular diseases. Copyright © 2013 John Wiley & Sons, Ltd.
    Phytotherapy Research 11/2013; 27(11). DOI:10.1002/ptr.4924 · 2.40 Impact Factor
  • Jung Won Kang · Byung-Sun Min · Jeong-Hyung Lee
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    ABSTRACT: Platelets play a critical role in pathogenesis of cardiovascular disorders and strokes. The inhibition of platelet function is beneficial for the treatment and prevention of these diseases. In this study, we investigated the anti-platelet activity of erythro-(7S,8R)-7-acetoxy-3,4,3`,5`-tetramethoxy-8-O-4`-neolignan (EATN), a neolignan isolated from Myristica fragrans, using human platelets. EATN preferentially inhibited thrombin- and platelet-activating factor (PAF)-induced platelet aggregation without affecting platelet damage in a concentration-dependent manner with IC(50) values of 3.2 ± 0.4 and 3.4 ± 0.3 μM, respectively. However, much higher concentrations of EATN were required to inhibit platelet aggregation induced by arachidonic acid. EATN also inhibited thrombin-induced serotonin and ATP release, and thromboxane B(2) formation in human platelets. Moreover, EATN caused an increase in cyclic AMP (cAMP) levels and attenuated intracellular Ca(2+) mobilization in thrombin-activated human platelets. Therefore, we conclude that the inhibitory mechanism of EATN on platelet aggregation may increase cAMP levels and subsequently inhibit intracellular Ca(2+) mobilization by interfering with a common signaling pathway rather than by directly inhibiting the binding of thrombin or PAF to their receptors. This is the first report of the anti-platelet activity of EATN isolated from M. fragrans. Copyright © 2013 John Wiley & Sons, Ltd.
    Phytotherapy Research 11/2013; 27(11). DOI:10.1002/ptr.4923 · 2.40 Impact Factor
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    ABSTRACT: IL-32 is known to play an important role in inflammatory and autoimmune disease responses. In addition to its role in these responses, IL-32 and its different isoforms have in recent years been implicated in the development of various cancers. As of yet, the role of IL-32 in breast cancer has remained largely unknown. By performing immunohistochemical assays on primary breast cancer samples, we found that the level of IL-32β expression was positively correlated with tumor size, number of lymph node metastases and tumor stage. In addition, we found that breast cancer-derived MDA-MB-231 cells exogenously expressing IL-32β exhibited increased migration and invasion capacities. These increased capacities were found to be associated with an increased expression of the epithelial mesenchymal transition (EMT) markers vimentin and Slug, the latter of which is responsible for the increase in vimentin transcription. To next investigate whether IL-32β enhances migration and invasion through a soluble factor, we determined the levels of several migration-stimulating ligands, and found that the production of VEGF was increased by IL-32β. In addition, we found that IL-32β-induced VEGF increased migration and invasion through STAT3 activation. The IL-32β-VEGF-STAT3 pathway represents an additional pathway that mediates the migration and invasion of breast cancer cells under the conditions of normoxia and hypoxia.
    10/2013; 36(6). DOI:10.1007/s13402-013-0154-4
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    ABSTRACT: Syntenin is an adaptor molecule containing 2 PDZ domains which mediate molecular interactions with diverse integral or cytoplasmic proteins. Most of the results on the biological function of syntenin were obtained from studies with malignant cells, necessitating exploration into the role of syntenin in normal cells. To understand its role in normal cells, we investigated expression and function of syntenin in human lymphoid tissue and cells in situ and in vitro. Syntenin expression was denser in the germinal center than in the extrafollicular area. Inside the germinal center, syntenin expression was obvious in follicular dendritic cells (FDCs). Flow cytometric analysis with isolated cells confirmed a weak expression of syntenin in T and B cells and a strong expression in FDCs. In FDC-like cells, HK cells, most syntenin proteins were found in the cytoplasm compared to weak expression in the nucleus. To study the function of syntenin in FDC, we examined its role in the focal adhesion of HK cells by depleting syntenin by siRNA technology. Knockdown of syntenin markedly impaired focal adhesion kinase phosphorylation in HK cells. These results suggest that syntenin may play an important role in normal physiology as well as in cancer pathology.
    Immune Network 10/2013; 13(5):199-204. DOI:10.4110/in.2013.13.5.199
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    Jongkyu Lee · Nara Tae · Jung Joon Lee · Taeho Kim · Jeong-Hyung Lee
    European Journal of Pharmacology 05/2013; 708(s 1–3):139. DOI:10.1016/j.ejphar.2013.04.001 · 2.68 Impact Factor
  • Jungwon Kang · Nara Tae · Byung Sun Min · Jongseon Choe · Jeong-Hyung Lee
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    ABSTRACT: Malabaricone C (MLB-C), isolated from nutmeg, is a phenolic diarylnonanoid that is known to exert a variety of pharmacological activities. In the present study, we investigated the molecular actions of MLB-C against lipopolysaccharide (LPS)-induced inflammatory responses in RAW264.7 cells and murine peritoneal macrophages. MLB-C inhibited the production of nitric oxide (NO), prostaglandin E(2) (PGE(2)), interleukin-6 (IL-6), and interferon-γ (INF-γ) in a dose-dependent manner. Consistent with NO and PGE(2) inhibition, MLB-C suppressed LPS-induced inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expression as well as the promoter activities of COX-2 and iNOS. MLB-C pretreatment prevented LPS-induced nuclear factor-kappa B (NF-κB) activation through the inhibition of phosphorylation of IκB kinase (IKK), phosphorylation and degradation of IκBα, and nuclear translocation of NF-κB. In addition, MLB-C blocked LPS-induced serine 536 phosphorylation and transcriptional activity of RelA/p65 subunit of NF-κB. Further study demonstrated that MLB-C inhibited LPS-induced Akt phosphorylation, which is an upstream activator of NF-κB, by reducing reactive oxygen species (ROS) accumulation, without affecting phosphorylation of mitogen-activated protein kinases (MAPKs). These findings indicate that MLB-C exerts an anti-inflammatory effect through the inhibition of NF-κB activation by inhibiting interconnected ROS/Akt/IKK/NF-κB signaling pathways.
    International immunopharmacology 08/2012; 14(3):302-10. DOI:10.1016/j.intimp.2012.08.006 · 2.71 Impact Factor
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    ABSTRACT: Malabaricone C (Mal-C), isolated from nutmeg, is known to exert a variety of pharmacological activities. However, the effect of Mal-C on vascular smooth muscle cells (VSMCs) is unknown. This study examined the effect of Mal-C on proliferation and migration of primary rat aortic smooth muscle cells (RASMCs) as well as its underlying mechanisms. Treatment of RASMCs with Mal-C induced both protein and mRNA expression of heme oxygenase-1 (HO-1) in a dose- and time-dependent manner. Mal-C-mediated HO-1 induction was inhibited by treatment with actinomycin D or by cycloheximide. SB203580 (a p38 inhibitor), SP600125 (a JNK inhibitor), U0126 (a MEK inhibitor), and N-acetylcysteine (NAC, an antioxidant) did not suppress Mal-C-induced HO-1 expression. In contrast, LY294002 (a PI3K inhibitor) blocked Mal-C-induced HO-1 expression. Moreover, RASMCs treated with Mal-C exhibited activation of AKT in a dose- and time-dependent manner. Treatment of RASMCs with Mal-C increased nuclear translocation of nuclear factor-E2-related factor 2 (Nrf2), which is a key regulator of HO-1 expression, and this translocation was also inhibited by LY294002. Consistent with the notion that HO-1 has protective effects against VSMCs, Mal-C remarkably inhibited platelet-derived growth factor (PDGF)-induced proliferation and migration of RASMCs. However, inhibition of HO-1 significantly attenuated the inhibitory effects of Mal-C on PDGF-induced proliferation and migration of RASMCs. Taken together, these findings suggest that Mal-C could suppress PDGF-induced proliferation and migration of RASMCs through Nrf2 activation and subsequent HO-1 induction via the PI3K/AKT pathway, and may be a potential HO-1 inducer for preventing or treating vascular diseases.
    Journal of Cellular Biochemistry 04/2012; 113(9):2866-76. DOI:10.1002/jcb.24161 · 3.37 Impact Factor
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    ABSTRACT: Macrophage inhibitory cytokine-1 (MIC-1) is highly associated with malignant human cancers and has been suggested to be involved in tumor angiogenesis. In the present study, we examined the effect of MIC-1 on endothelial cell proliferation to confirm the angiogenesis-promoting role of MIC-1. MIC-1 treatment accelerated progression of the G(1) stage in the cell cycle of human umbilical vein endothelial cells (HUVECs), leading to an increased cell proliferation rate. MIC-1 augmented the levels of cyclins D1 and E without altering the levels of cyclin-dependent kinase (CDK) inhibitors, thereby increasing protein kinase activity of CDKs and subsequent phosphorylation of the Rb protein followed by nuclear translocation of E2F. MIC-1-induced expression of cyclins D1 and E was mediated by AP-1 and E2F-1 transcription factors, and among the AP-1 members, c-Jun and JunD appeared to participate in MIC-1-dependent transcription of the cyclin D1 gene. Additionally, the PI3K/Akt, JNK, and ERK pathways were found to mediate MIC-1-induced cyclin D1 expression in HUVECs. Importantly, lung endothelial cells isolated from MIC-1 transgenic mouse displayed a higher proliferation rate and cyclin D1 and E levels relative to their wild-type counterparts. These results suggest that MIC-1 secreted from cancer cells stimulates endothelial cell proliferation by enhancing AP-1- and E2F-dependent expression of G(1) cyclins via PI3K/Akt, JNK, and ERK signaling pathways, potentially leading to enhanced tumor angiogenesis.
    Cellular Signalling 03/2012; 24(8):1485-95. DOI:10.1016/j.cellsig.2012.03.014 · 4.47 Impact Factor
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    ABSTRACT: Tangeretin, a natural polymethoxylated flavone concentrated in the peel of citrus fruits, is known to have antiproliferative, antiinvasive, antimetastatic and antioxidant activities. However, the effect of tangeretin on vascular smooth muscle cells (VSMCs) is unknown. This study examined the effect of tangeretin on platelet-derived growth factor (PDGF)-BB-induced proliferation and migration of rat aortic smooth muscle cells (RASMCs) as well as its underlying mechanisms. Tangeretin significantly inhibited proliferation, DNA synthesis and migration of PDGF-BB-stimulated RASMCs without inducing cell death. Treatment with tangeretin-induced cell-cycle arrest in the G₀/G₁ phase was associated with down-regulation of cyclin D1 and cyclin E in addition to up-regulation of p27(kip1). We also showed that tangeretin inhibited PDGF-BB-induced phosphorylation of AKT, while it had no effect on the phosphorylation of phospholipase Cγ (PLCγ), PDGF receptor β-chain (PDGF-Rβ) and extracellular signal-regulated kinase 1/2 (ERK1/2), c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinases (MAPKs). An in vitro kinase assay revealed that tangeretin inhibited AKT activity in a dose-dependent manner. Moreover, treatment of LY294002, a phosphoinositide 3-kinase (PI3K) inhibitor, had similar effects than that of tangeretin on the expression of p27(kip1) and cyclin D1, as well as cell migration in PDFG-BB-stimulated RASMCs. Taken together, these findings suggest that tangeretin could suppress PDGF-BB-induced proliferation and migration of RASMCs through the suppression of PI3K/AKT signaling pathway, and may be a potential candidate for preventing or treating vascular diseases, such as atherosclerosis and restenosis.
    European journal of pharmacology 12/2011; 673(1-3):56-64. DOI:10.1016/j.ejphar.2011.10.011 · 2.68 Impact Factor
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    Yunjin Choi · Jeong-Hyung Lee
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    ABSTRACT: 2-Deoxy-D-glucose (2-DG), a synthetic glucose analog that acts as a glycolytic inhibitor, is currently under clinical evaluation for targeting tumor cells. Tephrosin (TSN), a plant rotenoid, is known as an anticancer agent. In this study, we describe that the addition of TSN to 2-DG enhanced the cytotoxic activity of 2-DG against various types of cancer cells by accelerating ATP depletion and blunting autophagy. TSN increased the sensitivity of cancer cells to the cytotoxic effect of 2-DG. The combination of TSN and 2-DG induced acceleration of intracellular ATP depletion and the drastic activation of AMP-activated protein kinase (AMPK), which resulted in the inactivation of the mammalian target of rapamycin (mTOR) pathway. Of particular interest, TSN suppressed 2-DG-induced autophagy, a cell survival process in response to nutrient deprivation. We also showed that TSN inhibited 2-DG-induced activation of elongation factor-2 kinase (eEF-2K), which has been known to regulate 2-DG-induced autophagy. Inhibition of eEF-2K by RNA interference blunted 2-DG-induced autophagy and increased the sensitivity of cancer cells to the cytotoxic effect of 2-DG. The addition of TSN to 2-DG, however, did not enhance the cytotoxic activity of 2-DG by knockdown of eEF-2K, suggesting that inhibition of eEF-2K by tephrsoin could be a critical role in the potentiating effect of TSN on the cytotoxicity of 2-DG. Furthermore, we showed that the blunted autophagy and enhanced cytotoxicity of 2-DG was accompanied by the augmentation of apoptosis. These results show that TSN may be valuable for augmenting the therapeutic efficacy of 2-DG.
    Cancer biology & therapy 12/2011; 12(11):989-96. DOI:10.4161/cbt.12.11.18364 · 3.63 Impact Factor

Publication Stats

1k Citations
209.04 Total Impact Points

Institutions

  • 2007–2015
    • Kangwon National University
      • Department of Biochemistry
      Shunsen, Gangwon-do, South Korea
  • 1998–2008
    • Korea Research Institute of Bioscience and Biotechnology KRIBB
      • Anticancer Research Laboratory
      Anzan, Gyeonggi Province, South Korea
  • 2004
    • Chungnam National University
      Daiden, Daejeon, South Korea