• Molecular & Cellular Toxicology
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• v.4 no.2
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• pp.144-149
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• 2008

Despite versatile activity (cancericidal, antimicrobial, hypoxia inducible factor (HIF) inhibition, immune deactivation of DNA bis-intercalation agent, echinomycin, its specific mechanism has been elusive. Of these novel mechanisms, we reported that using human colon cancer cells (HT-29), apoptotic machinery induced by echinomycin might be dependent of caspase-3 pathway. Despite a partial enlightenment of prototypic signal path triggered by echinomycin, the role of Bcl-2 in this signaling pathway is unclear. To address this issue, we explored whether or not echinomycin would overcome the anti-apoptotic impact of Bcl-2 in HT-29 cells by the controlled Bcl-2 overexpression. Prior to this proof, we confirmed that echinomycin induces mitochondrial depolarization, then triggering the mitochondrial pathway of apoptosis with an involvement of upstream cas-pases-3. Transiently transfection with inactive Bax-DNA failed to prevent echinomycin-induced apoptosis in HT-29 cells. To dissect the role of Bcl-2 in echinomycin-induced apoptosis, HT-29 cells were transiently transfected with Bcl-2 DNA for overexpression and then treated with echinomycin for 24h. Combined analyses of DNA fragmentation and flow cytometric analysis clearly verified that echinomycin-induced apoptosis was drastically attenuated by Bcl-2 overexpression, whereas a control vector rarely affected echinomycin-induced apoptosis. Collectively, these data verify that Bcl-2 regulates echinomycin-induced apoptosis in HT-29 cells. To my knowledge, this is the first evidence that of diverse, structured minor groove binders (MGB), the prototypic echinomycin might control the apoptotic signaling via Bcl-2-mitochondrial pathway.

• Journal of Microbiology and Biotechnology
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• v.25 no.3
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• pp.413-417
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• 2015

Recently, we isolated HY253, a novel decahydrofluorene analog with a molecular structure of 7,8a-divinyl-2,4a,4b,5,6,7,8,8a,9,9a-decahydro-1H-fluorene-2,4a,4b,9a-tetraol from the roots of Aralia continentalis, which is known as Dokwhal (獨活), a traditional medicinal herb. Moreover, we previously reported its cytotoxic activity on cancer cell proliferation in human lung cancer A549 and cervical cancer HeLa cells. The current study aimed to evaluate its detailed molecular mechanisms in cell cycle arrest and apoptotic induction in human hepatocellular carcinoma HepG2 cells. Flow cytometric analysis of HepG2 cells treated with $60{\mu}M$ HY253 revealed appreciable cell cycle arrest at the G1 phase via inhibition of Rb phosphorylation and down-regulation of cyclin D1. Furthermore, using western blots, we found that up-regulation of cyclin-dependent kinase inhibitors, such as p21^CIP1 and p27^KIP1, was associated with this G₁ phase arrest. Moreover, TUNEL assay and immunoblottings revealed apoptotic induction in HepG2 cells treated with $60{\mu}M$ HY253 for 24 h, which is associated with cytochrome c release from mitochondria, via down-regulation of anti-apoptotic Bcl-2 protein, which in turn resulted in activation of caspase-9 and -3, and proteolytic cleavage of poly(ADP-ribose) polymerase (PARP). Accordingly, we suggest that HY253 may be a potent chemotherapeutic hit compound for treating human liver cancer cells via up-regulation and activation of the p53 gene.

• Journal of Pharmacopuncture
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• v.12 no.3
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• pp.49-59
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• 2009

Background : Anticancer effects of herbal medicine have been reported in various types of cancer, but the systematic approaches to explain molecular mechanism(s) are not established yet. Objective : The purpose of this study is to investigate the apoptotic cell death by Egg White combined Chalcanthite in NCI-H460 human lung cancer cells. Methods : Inhibitory effects were estimated by the MTT-assay. Cancer cells were stained with DAPI and showed condensed and fragmented nuclei. The expression of cleaved caspase-3, bcl-2, and bax was detected by western blotting. To establish a basis of understanding for anti-cancer mechanism, whole proteins have been obtained from NCI-H460 harvested at 24 hrs after the treatment of Egg White combined Chalcanthite, protein expression has been profiled by 2DE-based proteomic approach. Results : NCI-H460 human lung cancer cells were treated by three samples of IS3, IS4 and IS5. IS4 inhibited most effectively the growth of NCI-H460 human lung cancer cells. The expression of cleaved caspase-3 increased in IS4 in a concentration-dependent manner. Various changes of the protein expression have been monitored, and most frequent dysregulation was found in Vimentin, Lamin-A/C. Conclusion : Egg White combined-Chacanthite inhibited the growth of NCI-H460 human lung cancer cells by inducing the apoptotic cell death via caspase-3 activation. Based upon the present findings, the further study will focus on monitoring various cancer survival factors after artificial regulation of the proteins identified, and it would be the basis for the understanding of the Chacabthite anticancer effect(s) at the molecular level.

• Journal of Ginseng Research
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• v.34 no.2
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• pp.138-144
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• 2010

Ginseng (Panax ginseng C.A. Meyer) has been shown to have anti-stress effects in animal studies. However, most studies have only managed to detect altered levels of biomarkers or enzymes in blood or tissue, and the actual molecular mechanisms by which ginseng exerts these effects remain unknown. In this study, the anti-oxidative effect of Korean red ginseng (KRG) was examined in human SK-N-SH neuroblastoma cells. Incubation of SK-N-SH cells with the oxidative stressor hydrogen peroxide resulted in significant induction of cell death. In contrast, pre-treatment of cells with KRG decreased cell death significantly. To elucidate underlying mechanisms by which KRG inhibited cell death, the expression of apoptosis-related proteins was examined by Western blot analysis. KRG pre-treatment decreased the expression of the pro-apoptotic gene caspase-3, whereas it increased expression of the anti-apoptotic gene Bcl-2. Consistent with this, immunoblot analysis showed that pre-treatment of the SK-N-SH cells with KRG inhibited expression of the pro-inflammatory gene cyclooxygenase 2 (COX-2). RT-PCR analysis revealed that the repression of COX-2 expression by KRG pre-treatment occurred at the mRNA level. Taken together, our data indicate that KRG can protect against oxidative stress-induced neuronal cell death by repressing genes that mediate apoptosis and inflammation.

• BMB Reports
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• v.41 no.2
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• pp.119-125
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• 2008

Our previous work confirmed that Sph2/LA1029 was a sphigomyelinase-like hemolyisn of Leptospira interrogans serogroup Icterohaemorrhagiae serovar Lai. Characteristics of both hemolytic and cytotoxic activities of Sph2 were reported in this paper. Sph2 was a heat-labile neutral hemolysin and had similar hemolytic behavior as the typical sphingomyelinase C of Staphylococcus aureus upon sheep erythrocytes. The cytotoxic activity of Sph2 was shown in mammalian cells such as BALB/C mouse lymphocytes and macrophages, as well as human L-02 liver cells. Transmission electron microscopic observation showed that the Sph2 treated BALB/C mouse lymphocytes were swollen and ruptured with membrane breakage. They also demonstrated condensed chromatin as a high-density area. Cytoskeleton changes were observed via fluorescence confocal microscope in Sph2 treated BALB/C mouse lymphocytes and macrophages, where both cytokine IL-$1{\beta}$ and IL-6 were induced. In addition, typical apoptotic morphological features were observed in Sph2 treated L-02 cells via transmission electron microscope and the percentage of apoptotic cells did increase after the Sph2 treatment detected by flow cytometry. Therefore, Sph2 was likely an apoptosis-inducing factor of human L-02 liver cells.

• Journal of Physiology & Pathology in Korean Medicine
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• v.24 no.6
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• pp.942-949
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• 2010

Morus alba L., a kind of Oriental medicinal herbs, has been traditionally used to treat pulmonary asthma and congestion. According to recent studies, extracts of M. alba L. have showed anti-inflammatory, anti-oxidant, anti-tumor and hypoglycemic effects. However, the molecular mechanisms on how it acts as a death-inducer in cancer cells have not been fully understood. In this study, we investigated the cell death effects of methylene chloride extracts of M. alba L. (MEMA) in A549 human lung carcinoma cells. It was shown that MEMA induced the apoptotic cell death proved by increased sub-G1 phase cell population, apoptotic body formation and chromatin condensation. MEMA treatment induced the expression of death receptor-related proteins such as death receptor (DR) 4, DR5, Fas and FasL, which further triggered the activation of caspase-8 and the cleavage of Bid in a concentration-dependent manner. However, MEMA reduced anti-apoptotic Bcl-2 and Bcl-xL expression which contributed to the loss of mitochondrial membrane potential (MMP), and the activations of caspase-9 and caspase-3. Meanwhile, the morphological study indicated a characteristic finding of autophagy, such as the formation of autophagosomes in MEMA-treated cells. Furthermore, markers of autophagy, namely, the increased MDC-positive cells, conversion of microtubule-associated protein light chain 3 (LC3)-I to LC3-II and increased beclin-1 accumulation, were observed. Taken together, these findings demonstrated that MEMA triggered both autophagy and apoptosis in A549 cancer cells. They might suggest that M. alba L. could be a prospective clinical application to treat human lung cancers.

• Biomolecules & Therapeutics
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• v.15 no.3
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• pp.137-144
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• 2007

Although lovastatin, a competitive inhibitor of 3-hydroxy-3-methylglutaryl-coenzyme A (HMGCoA) reductase, has been shown to have anti-cancer actions, the effect on human hepatoma cells was not investigated. Moreover, the exact mechanism of this action is not fully understood. In this study we investigated the mechanism by which lovastatin induces apoptosis using HepG2 human hepatoblastoma cells. Lovastatin induced apoptotic cell death in a dose-dependent manner in the cells, assessed by the flow cytometric analysis. Treatment with mevalonic acid, a precursor of cholesterol, did not significantly suppress the lovastatin-induced apoptosis. Lovastatin induced a rapid and sustained increase in intracellular $Ca^{2+}$ concentration. Treatment with EGTA, an extracellular $Ca^{2+}$ chelator did not significantly alter the lovastatin-induced intracellular $Ca^{2+}$ increase and apoptosis, whereas intracellular $Ca^{2+}$ reduction with BAPTA/AM and intracellular $Ca^{2+}$ release blockers (dantrolene and TMB-8) completely blocked these actions of lovastatin. In addition, the lovastatin-induced apoptosis was significantly reduced by a calpain inhibitor, a broad spectrum caspase inhibitor z-VAD-fmk and inhibitors specific for caspase-9 and caspase-3 (z-LEHD-fmk and z-DEVD-fmk, respectively), but not by an inhibitor specific for caspase-8 (z-IETD-fmk). Collectively, these results suggest that lovastatin induced apoptosis of HepG2 hepatoma cells through intracellular $Ca^{2+}$ release and calpain activation, leading to triggering mitochondrial apoptotic pathway. These results further suggest that lovastatin may be valuable for the therapeutic management of human hepatoma.

• The Korea Journal of Herbology
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• v.26 no.4
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• pp.67-74
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• 2011

Objectives : The purpose of the study is to determine the neuroprotective effects of the water extract of Angelicae Acutilobae Radix(AA) on ischemia reperfusion-induced apoptosis in SK-N-SH human brain neuronal cells. Methods: SK-N-SH cells were treated with different concentrations of AA water extract (0.1, 0.2, 0.5 and 1.0 mg/ml) for 2 hr and then stimulated with Dulbecco's phosphate-buffered saline containing CI-DPBS: 3mM sodium azide and 10 mM 2-deoxy-D-glucose for 45 min, reperfused with growth medium, and incubated for 24 h. Cell viability was determined by WST-1 assay, and ATP/ADP levels were measured by ADP/ATP ratio assay kit. The levels of caspase-3 protein were determined by Western blot and apoptotic body was observed by Hoechst 33258 staining. Results : AA extract significantly inhibited decreasing the cell viability in ischemia-induced SK-N-SH cells. AA also increased the ratio of ADP/ATP in ischemia-induced neuronal cells and decreased the expression levels of apoptotic protein, caspase-3 and apoptotic DNA damage. Conclusions : Our results suggest that AA extract has a neuroprotective property via suppressing the apoptosis and increasing the energy levels in neuronal cells, suggesting that AA extract may has a therapeutic potential in the treatment of ischemic brain injury.

• The Journal of Korean Medicine
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• v.31 no.3
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• pp.55-65
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• 2010

Background: Nitric oxide (NO) is a reactive free radical gas and a messenger molecule. NO has many physiological functions, but excessive NO production induces neurotoxicity. Objective: The present study investigated whether the aqueous extract of Polygala tenuifolia Willdenow possesses a protective effect on NO-induced apoptosis in human neuroblastoma cell line SK-N-MC. Method: For this study, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, 4,6-diamidino-2-phenylindole (DAPI) staining, terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick end labeling (TUNEL) assay, DNA fragmentation assay, reverse transcription-polymerase chain reaction (RT-PCR), Western blot, and caspase-3 enzyme assay were performed. Result: Sodium nitroprusside (SNP) exposure significantly decreased the viability of cells. The cells treated with SNP exhibited several apoptotic features such as increasing of Bax expression, caspase-3 enzyme activity and inhibiting of Bcl-2 expression. On the other hand, the viability of cells pre-treated with the aqueous extract of Polygala tenuifolia Willdenow was increased dose-dependently. The cells pre-treated for 1 h with the aqueous extract of Polygala tenuifolia Willdenow followed by treatment with SNP showed a decreased occurrence of apoptotic features like decreasing Bax expressions, caspase-3 enzyme activity and increasing Bcl-2 expressions. The aqueous extract of Polygala tenuifolia Willdenow reduced apoptotic cell death in neuroblastoma cell line SK-N-MC through the inhibition of Bax-dependent caspase-3 activation and the increasing of Bcl-2 expression. Conclusion: Based on the present results, it is possible that Polygala tenuifolia Willdenow has therapeutic value for the treatment of a variety of NO-induced brain diseases.

• BMB Reports
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• v.37 no.4
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• pp.480-486
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• 2004

Brain ischemia brings about hypoxic insults. Hypoxia is one of the major pathological factors inducing neuronal injury and central nervous system infection. We studied the involvement of mitogen-activated protein (MAP) kinase in hypoxia-induced apoptosis using cobalt chloride in C6 glioma cells. In vitro cytotoxicity of cobalt chloride was tested by MTT assay. Its $IC_{50}$ value was $400\;{\mu}M$. The DNA fragment became evident after incubation of the cells with $300\;{\mu}M$ cobalt chloride for 24 h. We also evidenced nuclear cleavage with morphological changes of the cells undergoing apoptosis with electron microscopy. Next, we examined the signal pathway of cobalt chloride-induced apoptosis in C6 cells. The activation of extracellular signal-regulated protein kinase 1/2 (ERK 1/2) started to increase at 1 h and was activated further at 6 h after treatment of 400 M cobalt chloride. In addition, pretreatment of PD98059 inhibited cobalt chloride-induced apoptotic cell morphology in Electron Microscopy. These results suggest that cobalt chloride is able to induce the apoptotic activity in C6 glioma cells, and its apoptotic mechanism may be associated with signal transduction via MAP kinase (ERK 1/2).