• Archives of Pharmacal Research
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• v.21 no.6
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• pp.683-687
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• 1998

We have examined in vitro and in vivo radioprotective effects of a well-known thiol-containing compound, dithiothreitol (DTT). The treatment of both 0.5 and 1mM of DTT significantly increased clonogenic survival of ${\gamma}$-ray irradiated Chinese hamster (V79-4) cells. In order to investigate the possible radioprotective mechanism of DTT, we measured gamma-ray induced chromosome aberration by micronucleus assay. In the presence of 0.5mM or 1mM DTT, the frequencies of micronuclei were greatly reduced in all dose range examined (1.5-8 GY). Slightly higher reduction in micronucleus formation was observed in 1mM DTT-treated cells than in 0.5mM DTT-treated cells. In addition, incubation with both 0.5 and 1mM of DTT prior to gamma-ray irradiation reduced nucleosomal DNA fragmentation at about same extent, this result suggests that treatment of DTT at concentrations of 0.5 and 1mM reduced radiation-induced apoptosis. In vivo experiments, we also observed that DTT treatment reduced the incidence of apoptotic cells in mouse small intestine crypts. In irradiated control group 4.4${\pm}$0.5 apoptotic cells per crypt were observed. In DTT-administered and irradiated mice, only 2.1${\pm}$0.4 apoptotic cells per crypt was observed. In vitro and in vivo data obtained in this study showed that DTT reduced radiation-induced damages and it seems that the possible radioprotective mechanisms of action of DTT are prevention of chromosome aberration.

• Korean Journal of Medicinal Crop Science
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• v.17 no.2
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• pp.145-150
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• 2009

This study investigated the protective roles and mechanism of magnolol, from the stem bark of Magnolia officinalis against potential neurotoxin 3-hydroxykynurenine (3-HK)-induced neuronal cell death. For the evaluation of protective role of magnolol, we examined cell viability, apoptotic nuclei, change of mitochondrial membrane potential and caspase activity in human neuroblastoma SH-SY5Y cells. It was found that 3-HK induces neuronal cell death in the human neuroblastoma SH-SY5Y cell line. The reduced cell viability produced characteristic features such as cell shrinkages, plasma membrane blebbing, chromatin condensation, and nuclear fragmentation. The cells treated with 3-HK showed an increase in the concentration of reactive oxygen species (ROS) as well as in caspase activity. In addition, both are involved in the 3-HK-induced apoptosis. Magnolol attenuated the cell viability reduction by 3-HK in both a dose- and time-dependent manner. Optical microscopy showed that magnolol inhibited the cell morphological features in the 3-HK-treated cells. Furthermore, the increase in the ROS concentration and the caspase activities by 3-HK were also attenuated by magnolol. These results showed that magnolol has a protective effect on the 3-HK induced cell death by inhibiting ROS production and caspase activity.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.11
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• pp.4475-4482
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• 2014

Background: Cisplatin, a DNA damaging agent, induces apoptosis through increasing DNA fragmentation. However, identification of intrinsic resistance molecules against Cisplatin is vital to estimate the success of therapy. Bag-1 (Bcl-2-associated anthanogene) is one anti-apoptotic protein involved in drug resistance impacting on therapeutic efficiency. Elevated levels of this protein are related with increase cell proliferation rates, motility and also cancer development. For this reason, we aimed to understand the role of Bag-1 expression in Cisplatin-induced apoptosis in HeLa cervix cancer cells. Cisplatin decreased cell viability in time- and dose-dependent manner in wt and Bag-1L+HeLa cells. Although, $10{\mu}M$ Cisplatin treatment induced cell death within 24h by activating caspases in wt cells, Bag-1L stable transfection protected cells against Cisplatin treatment. To assess the potential protective role of Bag-1, we first checked the expression profile of interacting anti-apoptotic partners of Bag-1. We found that forced Bag-1L expression prevented Cisplatin-induced apoptosis through acting on Mcl-1 expression, which was reduced after Cisplatin treatment in wt HeLa cells. This mechanism was also supported by the regulation of heat shock protein (Hsp) family members, Hsp90 and Hsp40, which were involved in the regulation Bag-1 interactome including several anti-apoptotic Bcl-2 family members and c-Raf.

• Journal of Nutrition and Health
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• v.40 no.2
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• pp.138-146
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• 2007

Food irradiation has been steadily increased in many countries concomitantly with increasing international trades. Harmful contaminants naturally occurred from foods which contain high levels of unsaturated fatty acids that are easily oxidized can affect the human anti-oxidation system through the generation of free radicals. Moreover, previous studies proved that ${\gamma}$-irradiation may cause production of free radicals in food. We investigated the effect of ${\gamma}$-irradiated soybeans in relation to oxidative stress in mice. Oxidative index of mice was evaluated by TBARS, DNA fragmentation in various organs such as blood lymphocytes, liver and kidney. Forty male ICR mice were equally divided into 4 groups and fed control diet or ${\gamma}$-irradiated diet containing 50% soybeans (5, 10, and 20 kGy, respectively) for 8 weeks. Peroxide values of the irradiated diets were higher than that of the non-irradiated one and increased according to the storage period. There was no significant difference in weight gain as well as in TBARS value in plasma and kidney of all groups. Liver TBARS value of the group fed with irradiated diet at 20 kGy increased significantly compared with the control group (p < 0.05). DNA oxidative damage as measured by alkaline comet assay showed that % tail DNA in the blood lymphocytes of 5 kGy and 10 kGy groups increased significantly over the control group (p < 0.05). Also, tail moments of 5 kGy and 10 kGy groups were higher than that of the control group. Ultrastructural examination shows myeline figures and swollen mitochondria in parietal and intestinal epithelial cells of the group fed with irradiated diet. Therefore, considering unsaturated fatty acid content, consumption of soybeans ${\gamma}$-irradiated with over 20 kGy or repeatedly may decrease the body's antioxidant mechanism.

• Toxicological Research
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• v.16 no.1
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• pp.1-8
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• 2000

Astrocytes generate free radicals including nitric oxide (NO) and reactive oxygen intermediates(ROI) which in turn play roles in the pathogenesis of degenerative diseases and sclerotic changes of the brain. This study was designed to evaluate the mechanism that free radicals contribute to the cytotoxicty of rat neonatal primary astrocytes. Treatment with NO donors alone including soldium nitroprusside(SNP), S-nitrosoglucathinoe (GSNO), and S-nitroso-n-acetylpenicillamine (SNAP) showed a little effect on the death of rat neonatal primary astrocytes, whereas SNP markedly induced the death of RAW 264.7 cells. ROI inculding H2O2 and O2 donor also slightly induced the death of rat primary astrocytes. However, 3-morpholinosydnonimine(SIN-1), a donor of peroxynitrite (ONOO), which is a reactive compound of NO with superoxide, significantly decreased the viability of rat primary astrocytes in a dose-dependent manner. Cells were retarded in outgrowth of viability of cellular processes with cell shrinkage and detachment from culture dishes. Hoechst staining demonstrated that SIN-1-induced cell death might be due to an apoptosis which was characterized by nuclear condensation and fragmentation. SIN-1-induced apoptosis was prevented by the pretreatment with superoxide dismutase (SOD) and catalase in rat primary astorocytes. Furthermore, prevention of the generation of reduced glutathione (GSH) by DL-buthionine-[S, R]-sulfoximine (BSO) aggravated the cytotoxic effects of SNP, benzene triol, and SIN-1 in rat primary astrocytes. Taken together, it is suggested that peroxynitrite may be a major effector of apoptosis and cellular antioxidant system is important for cell survival in rat prima교 astrocytes.

• Journal of Physiology & Pathology in Korean Medicine
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• v.18 no.6
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• pp.1661-1665
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• 2004

Herba Patriniae(HP) has been known to exert anti-tumoral activity in Korea. However, its molecular mechanism, of action is not understood. In this study, we found that HP induced apoptosis in androgen-dependent prostate cancer DU145 cells as evidenced by DNA fragmentation and chromatine condensation in hoechst dye staining. Our data demonstrated that HP-induced apoptotic cell death was accompanied by activation of caspase-3 and cleavages of its substrates, poly(ADP-ribose) polymerase(PARP) in a time- and concentration-dependent manner. Taken together, these results suggest that HP induces the activation of caspase-3, degradation of PARP, and eventually leads to apoptotic cell death.

• Journal of Physiology & Pathology in Korean Medicine
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• v.18 no.6
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• pp.1733-1739
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• 2004

The water extract of Hwangryunhaedog-tang(HRHDT} has been traditionally used for treatment of ischemic heart and brain damage in oriental medicine. However, little is known about the mechanism by which the water extract of HRHDT rescues cells from these damages. This study was designed to investigate the protective mechanisms of HRHDT on hypoxia-induced cytotoxicity in H9c2 cardiomyoblast cells. Hypoxia, markedly decreased the viability of H9c2 cells, which was characterized with apparent apoptptic features such as chromatin condensation as well as fragmentation of genomic DNA and nuclei. However, HRHDT significantly reduced hypoxia-induced cell death and apoptotic characteristics. Also, HRHDT prevented the mitochondrial dysfunction including the disruption of mitochondria membrane permeability transition (MPT) and an increase in expression of anti-apoptotic Bcl-2 proteins in hypoxia-H9c2 cells. Taken together, this study suggests that the protective effects of the water extract of HRHDT against hypoxic damages may be mediated by the modulation of Bcl-2 and Bak expression.

• Journal of Physiology & Pathology in Korean Medicine
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• v.25 no.5
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• pp.816-822
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• 2011

Kaempferol, a component of Polygonati rhizoma, is one of the herbal flavonoids, which is used in therapeutic agent for anti-hypercholesterol, anti-hypertension and anti-diabetes. And it is also known to be effective in anti-cancer therapy for breast, prostate and other type of cancers. However, the anti-cancer therapeutic mechanisms are pooly understood. To address molecular mechanism underlying kaempferol-induced anti-cancer effects, we determined the effect of kaempferol on cell growth of the lung cancer cell lines, A549, H1299 and H460. From the FACS analysis, measurement of caspase activity, DAPI and tryptophan blue staining, and DNA fragmentation assay, we found that kaempferol induces apoptosis and H460 cells are most sensitive among the tested cell lines. In addition, we performed microarray to identify the genome-wide expression profiling regulated by kaempferol. Lots of cell cycle-related genes were under-expressed, whereas the genes related to TGF-beta/SMAD pathway were over-expressed in kaempferol-treated H460 cells. Additionally, kaempferol also increased expression levels of apoptosis related genes such as death receptors, FAS, TRAIL-R and TNF-R, and casepase-8 and caspase-10. Overall, our results suggest that kaempferol promotes anti-lung cancer therapeutic effects by inducing G1 arrest and apoptosis through TGF-beta/SMAD pathway and death receptors/caspase pathway, respectively.

• Biomolecules & Therapeutics
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• v.17 no.3
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• pp.282-287
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• 2009

Ochnaflavone is a natural biflavonoid and mainly found in the caulis of Lonicera japonica (Caprifoliaceae). Biological activities such as anti-inflammatory and anti-atherogenic effects have been previously reported. The anticancer activity of ochnaflavone, however, has been poorly elucidated yet. In the present study, we investigated the effect of ochnaflavone on the growth inhibitory activity in cultured human colon cancer cell line HCT-15. Ochnaflavone inhibited the proliferation of the cancer cells with an $IC_{50}$ value of $4.1{\mu}M$. Flow cytometric analysis showed that ochnaflavone arrested cell cycle progression in the G2/M phase, and induced the increase of sub-G1 peak in a concentration-dependent manner. Induction of cell cycle arrest was correlated with the modulation of the expression of cell cycle regulating proteins including cdc2 (Tyr15), cyclin A, cyclin B1 and cyclin E. The increase of sub-G1 peak by the higher concentrations of ochnaflavone (over $20{\mu}M$) was closely related to the induction of apoptosis, which was evidenced by the induction of DNA fragmentation, activation of caspase-3, -8 and -9, and cleavage of poly-(ADP-ribose) polymerase. These findings suggest that the cell cycle arrest and induction of apoptosis might be one possible mechanism of actions for the anti-proliferative activity of ochnaflavone in human colon cancer cells.

• 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.