Seon Min Woo

Keimyung University, Sŏul, Seoul, South Korea

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Publications (8)26.41 Total impact

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    ABSTRACT: Silibinin, an effective anti-cancer and chemopreventive agent, has been shown to exert multiple effects on cancer cells, including inhibition of both cell proliferation and migration. However, the molecular mechanisms responsible for these effects are not fully understood. We observed that silibinin significantly induced the expression of the non-steroidal anti-inflammatory drug-activated gene-1 (NAG-1) in both p53 wild-type and p53-null cancer cell lines, suggesting that silibinin-induced NAG-1 up-regulation is p53-independent manner. Silibinin up-regulates EGR-1 expression. The ectopic expression of EGR-1 significantly increased NAG-1 promoter activity and NAG-1 protein expression in a dose-dependent manner. Furthermore, down-regulation of EGR-1 expression using siRNA markedly reduced silibinin-mediated NAG-1 expression, suggesting that the expression of EGR-1 is critical for silibinin-induced NAG-1 expression. We also observed that reactive oxygen species (ROS) are generated by silibinin; however, ROS did not affect silibinin-induced NAG-1 expression and apoptosis. In addition, we demonstrated that the mitogen-activated protein kinase (MAP kinase) signal transduction pathway is involved in silibinin-induced NAG-1 expression. Inhibitors of p38 MAP kinase (SB203580) attenuated silibinin-induced NAG-1 expression. Furthermore, we found that siRNA-mediated knockdown of NAG-1 attenuated silibinin-induced apoptosis. Collectively, the results of this study demonstrate for the first time that up-regulation of NAG-1 contributes to silibinin-induced apoptosis in cancer cells.
    Chemico-biological interactions 01/2014; · 2.46 Impact Factor
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    ABSTRACT: Melatonin (N-acetyl-5-methoxytryptamine) has recently gained attention as an anti-cancer agent and for combined cancer therapy. In this study, we investigated the underlying molecular mechanisms of the effects of melatonin on cancer cell death. Treatment with melatonin induced apoptosis and up-regulated the expression of the pro-apoptotic protein Bcl-2-interacting mediator of cell death (Bim) in renal cancer Caki cells. Furthermore, down-regulation of Bim expression by siRNA markedly reduced melatonin-mediated apoptosis. Melatonin increased Bim mRNA expression through the induction of Sp1 and E2F1 expression and transcriptional activity. We found that melatonin also modulated Bim protein stability through the inhibition of proteasome activity. However, melatonin-induced Bim upregulation was independent of melatonin's antioxidant properties and the melatonin receptor. Taken together, our results suggest that melatonin induces apoptosis through the upregulation of Bim expression at the transcriptional level and at the post-translational level. This article is protected by copyright. All rights reserved.
    Journal of Pineal Research 10/2013; · 7.30 Impact Factor
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    ABSTRACT: Silymarin has been known as a chemopreventive agent, and possesses multiple anti-cancer activities including induction of apoptosis, inhibition of proliferation and growth, and blockade of migration and invasion. However, whether silymarin could inhibit prostaglandin (PG) E2 -induced renal cell carcinoma (RCC) migration and what are the underlying mechanisms are not well elucidated. Here, we found that silymarin markedly inhibited PGE2 -stimulated migration. PGE2 induced G protein-dependent CREB phosphorylation via protein kinase A (PKA) signaling, and PKA inhibitor (H89) inhibited PGE2 -mediated migration. Silymarin reduced PGE2 -induced CREB phosphorylation and CRE-promoter activity. PGE2 also activated G protien-independent signaling pathways (Src and STAT3) and silymarin reduced PGE2 -induced phosphorylation of Src and STAT3. Inhibitor of Src (Saracatinib) markedly reduced PGE2 -mediated migration. We found that EP2, a PGE2 receptor, is involved in PGE2 -mediated cell migration. Down regulation of EP2 by EP2 siRNA and EP2 antagonist (AH6809) reduced PGE2 -inudced migration. In contrast, EP2 agonist (Butaprost) increased cell migration and silymarin effectively reduced butaprost-mediated cell migration. Moreover, PGE2 increased EP2 expression through activation of positive feedback mechanism, and PGE2 -induced EP2 expression, as well as basal EP2 levels, were reduced in silymarin-treated cells. Taken together, our study demonstrates that silymarin inhibited PGE2 -induced cell migration through inhibition of EP2 signaling pathways (G protein dependent PKA-CREB and G protein-independent Src-STAT3). © 2013 Wiley Periodicals, Inc.
    Molecular Carcinogenesis 10/2013; · 4.27 Impact Factor
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    ABSTRACT: RU486 (mifepristone) exerts an anticancer effect on cancer cells via induction of apoptosis. However, the molecular mechanisms are not fully understood. Here, we investigated the effect of RU486 on the apoptosis of U937 human leukemia cells. RU486 markedly increased apoptosis in U937 cells as well as in MDA231 human breast carcinoma, A549 human lung adenocarcinoma epithelial and HCT116 human colorectal carcinoma cells. RU486 increased dose-dependent release of mitochondrial cytochrome c, and reduced the mitochondrial membrane potential (MMP, Δψm) in RU486‑treated U937 cells. We also found that overexpression of Bcl-2 completely blocked RU486-mediated apoptosis. However, reactive oxygen species signaling had no effect on RU486‑induced apoptosis. RU486 increased the phosphorylation of p38 MAPK and JNK, but p38 MAPK only was associated with RU486-mediated apoptosis. Taken together, RU486 induces apoptosis through reduction in the mitochondrial membrane potential and activation of p38 MAPK in U937 human leukemia cells.
    Oncology Reports 04/2013; · 2.30 Impact Factor
  • Seon Min Woo, Kyoung-Jin Min, Taeg Kyu Kwon
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    ABSTRACT: Withaferin A is a steroidal lactone purified from the Indian medicinal plant Withania somnifera. It exhibits a wide variety of activities, including anti-tumor, anti-inflammation, and immunomodulation properties. In this review, we focused on the anti-cancer effects of withaferin A. Withaferin A inhibits cell proliferation, metastasis, invasion, and angiogenesis in cancer cells. Furthermore, it sensitized irradiation, tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-, and doxorubicin-mediated apoptosis. The results showed that multiple mechanisms were involved in withaferin A-mediated anti-cancer effects. First, withaferin A increased intracellular reactive oxygen species (ROS) production and induced ER stress- and mitochondria-mediated apoptosis. Second, withaferin A inhibited the signaling pathways (Jak/STAT, Akt, Notch, and c-Met), which are important in cell survival, proliferation, and metastasis. Third, it induced apoptosis and inhibited cancer cell migration through the up-regulation of prostate apoptosis protein-4 (Par-4). Finally, withaferin A up-regulated pro-apoptotic protein expression levels through the inhibition of proteasome activity. Our findings suggested that withaferin A is a potential, potent therapeutic agent.
    Journal of Life Science. 01/2013; 23(3).
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    Seon Min Woo, Kyoung-Jin Min, Taeg Kyu Kwon
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    ABSTRACT: Calyculin A (Cal A) is a serine/threonine phosphatase inhibitor that is capable of inducing apoptosis in cancer cells. In this study, we examined whether Cal A could modulate TRAIL-induced apoptosis in human renal carcinoma-derived Caki cells. Our results show that Cal A is capable of sensitizing Caki cells to TRAIL-induced apoptosis, as well as U2OS human osteosarcoma cells and A549 human lung adenocarcinoma epithelial cells. Cal A increases intracellular ROS production and down-regulates c-FLIP(L) expression. Interestingly, the down-regulation of protein phosphatase 1 (PP1) by PP1 siRNA also reduced c-FLIP(L) expression via reactive oxygen species production. Furthermore, Cal A induced death receptor 4 (DR4) mRNA and protein expression by enhancing DR4 mRNA stability. We also found that PP4 siRNA up-regulated DR4 mRNA and protein expression. Collectively, our results suggest that Cal A could enhance TRAIL-mediated apoptosis via the down-regulation of c-FLIP(L) and the up-regulation of DR4 in human renal cell carcinoma cell line Caki.
    Apoptosis 08/2012; 17(11):1223-34. · 4.07 Impact Factor
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    ABSTRACT: Rottlerin, a selective inhibitor of novel isoforms of protein kinase C δ (PKC δ), has been shown to exert multiple effects on cancer cells, including inhibition of cell proliferation and migration. However, the molecular mechanisms responsible for these effects are not fully understood. We found that rottlerin dramatically induced non-steroidal anti-inflammatory drug activated gene-1 (NAG-1) expression in both p53 wild-type and p53-null cancer cell lines, suggesting that NAG-1 upregulation is a common response to rottlerin that occurs independently of p53 in multiple cell lines. Although rottlerin is known to inhibit PKC δ, PKC δ siRNA and overexpression of dominant-negative (DN)-PKC δ did not affect rottlerin-mediated induction of NAG-1. These results suggest that rottlerin induces NAG-1 upregulation via a PKC δ-independent pathway. We also observed that CHOP protein levels were significantly increased by rottlerin, but CHOP siRNA did not affect rottlerin-induced NAG-1 expression. In addition, we demonstrated the involvement of the mitogen-activated protein kinase (MAP kinase) signal transduction pathway in rottlerin-induced NAG-1 expression. Inhibitors of MEK (PD98059) and p38 MAP kinase (SB203580) prevented rottlerin-induced NAG-1 expression. Furthermore, we found that down-regulation of NAG-1 attenuated rottlerin-induced apoptosis. Collectively, the results of this study demonstrate, for the first time, that upregulation of NAG-1 contributes to rottlerin-induced apoptosis in cancer cells.
    Chemico-biological interactions 03/2012; 197(1):1-7. · 2.46 Impact Factor
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    ABSTRACT: TRAIL resistance in many cancer cells is one of the major problems in TRAIL-based cancer therapy. Thus, the agents that can sensitize the tumor cells to TRAIL-mediated apoptosis are strictly needed for the improvement of anti-cancer effect of TRAIL. Acrolein is a byproduct of lipid peroxidation, which has been involved in pulmonary, cardiac and neurodegenerative diseases. We investigated whether acrolein, an α,β-unsaturated aldehyde, can potentiate TRAIL-induced apoptosis in human renal cancer cells. The combined treatment with acrolein and TRAIL significantly induced apoptosis, and stimulated of caspase-3 activity, DNA fragmentation, and cleavage of PARP. We found that acrolein down-regulated the protein level of Bcl-2 and Bcl-2 overexpression inhibited the cell death induced by the combined treatment with acrolein and TRAIL. In addition, acrolein up-regulated C/EBP homologous protein (CHOP) and TRAIL death receptor 5 (DR5) and down-regulation of CHOP or DR5 expression using the respective small interfering RNA significantly attenuated the apoptosis induced by acrolein plus TRAIL. Interestingly, pretreatment with an antioxidant, N-acetylcysteine (NAC), inhibited not only CHOP and DR5 up-regulation but also the cell death induced by acrolein plus TRAIL. Taken together, our results demonstrated that acrolein enhances TRAIL-induced apoptosis in Caki cells through down-regulation of Bcl-2 and ROS dependent up-regulation of DR5.
    Experimental Cell Research 08/2011; 317(18):2592-601. · 3.56 Impact Factor