• BMB Reports
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• 제36권2호
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• pp.223-229
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• 2003

The product of a tree (Tabebuia avellanedae) from South America, $\beta$-lapachone, is known to exhibit various pharmacological properties, the mechanisms of which are poorly understood. The aim of the present study was to further elucidate the possible mechanisms by which $\beta$-lapachone exerts its anti-proliferative action in cultured human prostate cancer cells. We observed that the proliferation-inhibitory effect of $\beta$-lapachone was due to the induction of apoptosis, which was confirmed by observing the morphological changes and cleavage of the poly(ADP-ribose) polymerase protein. A DNA flow cytometric analysis also revealed that $\beta$-lapachone arrested the cell cycle progression at the G1 phase. The effects were associated with the down-regulation of the phosphorylation of the retinoblastoma protein (pRB) as well as the enhanced binding of pRB and the transcription factor E2F-1. Also, $\beta$-lapachone suppressed the cyclindependent kinases (Cdks) and cyclin E-associated kinase activity without changing their expressions. Furthermore, this compound induced the levels of the Cdk inhibitor $p21^{WAF1/CIP1}$ expression in a p53-independent manner, and the p21 proteins that were induced by $\beta$-lapachone were associated with Cdk2. $\beta$-lapachone also activated the reporter construct of a p21 promoter. Overall, our results demonstrate a combined mechanism that involves the inhibition of pRB phosphorylation and induction of p21 as targets for $\beta$-lapachone. This may explain some of its anticancer effects.

• 동의생리병리학회지
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• 제16권6호
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• pp.1143-1150
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• 2002

Recent evidence suggests that many Oriental Medicinal prescriptions are effective in cancer patients as a supportive care. Oriental Medicinal herbs have been investigated extensively and are known to have multiple pharmacological effect. These herbs contain a variety of ingredients which may act synergistically to inhibit tumor cell division, to increase tumor cell death (apoptosis), and to increase the proportion of immune cells within tumor. Paljinhangahm-dan (Paljin) has been used to treat for cancer patients in Oriental Medicine for decades. The effects of aqueous extract of Paljin on the induction of apoptotic cell death were investigated in human leukemia cell lines (HL-60, Jurkat, Molt-4 and U937). The viability of leukemia cells was markedly decreased by Paljin in a dose-dependent manner. Paljin induced the apoptotic death of leukemia cells, which was characterized by the ladder-pattern DNA fragmentation, and chromatin condensation of the nuclei. Paljin digested Bid protein but did not affect Bcl-2 protein level and also, induced mitochondrial dysfunction disrupted as shown as the mitochondrial membrane potential. It activated caspase-9 and caspase-3. thereby resulted in cleavage of poly(ADP) ribose polymerase(PARP). These results indicate that Paljin induces apoptosis of human leukemia cells via activation of intrinsic caspase cascades with mitochondrial dysfunction.

• 동의생리병리학회지
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• 제23권5호
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• pp.1154-1160
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• 2009

Androgen receptors (AR) play a crucial role in the development and progression of prostate cancer. Many studies have suggested that prostate cancer cell proliferation is inhibited by AR downregulation, and it has been reported that Takrisodokyeum (TRSDY) induced apoptotic cell death and suppressed tumorigenesis in human leukemia cells. Therefore, this study was conducted to elucidate the mechanism by which TRSDY affects cell growth and AR expression in androgen-dependent prostate cancer cells (LNCaP cells). We investigated the proliferation and apoptosis of LNCaP cells using MTT and DNA fragmentation assays. In addition, we used western blot analysis to assess the effects of TRSDY on the expression of the AR target gene, prostate-specific antigen (PSA). Furthermore, the mechanism of AR downregulation by TRSDY was investigated using EMSA to analyze the binding activity of AR to androgen response elements (ARE). TRSDY significantly suppressed proliferation and induced apoptosis in LNCaP cells. In addition, TRSDY-induced apoptotic cell death was accompanied by activation of caspase-3 and cleavage of its substrate, poly(ADP-ribose) polymerase. TRSDY also inhibited the constitutively expressed- or 5a-dihydrotestosterone (DHT)-induced AR/PSA protein levels. However, these effects were mediated by inhibition of the binding of AR to ARE. TRSDY-mediated AR/PSA downregulation contributes to the inhibition of cell proliferation and the induction of apoptosis in LNCaP human prostate cancer cells. Our findings suggest that TRSDY may be used as a chemopreventive or chemotherapeutic agent for the treatment of prostate cancer.

• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 2003년도 Annual Meeting of KSAP : International Symposium on Pharmaceutical and Biomedical Sciences on Obesity
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• pp.81-81
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• 2003

The present study was taken to examine the inhibitory effect of extracts of Scytosiphon lomentaria, a marine alga growing in Jeju Island, on the growth of cancer cells and to develop an anti-cancer agent using components of S. lomemtaria. The effect was observed by the measurement of metabolic activity using colorimetric 3-(4,5-dimethylthiazol)-2,5-diphenyltetrazolium bromide (MTT) assay. In results, crude extract of this alga markedly inhibited the growth of leukemia cell lines such as HL-60 and KG-1, but could scarcely inhibit the growth of normal cells (HEL299) and adenocarcinoma cells (SNU-16 and HCT-I5). When HL-60 cells were treated with the extract, DNA fragmentation and the increase of proportion of sub-G1 hypodiploid cells were observed. Therefore, the inhibitory effect of S. lomemtaria on the growth of HL-60 cells seems to arise from the induction of apoptosis. In order to understand the mechanism of apoptosis inducton by S. lomemtaria, we examined the changes of Bcl-2 and Bax expression. The extract reduced Bcl-2, an anti-apoptotic protein, but increased Bax, a pro-apoptotic protein in a dose-dependent manner. When we examined the activation of caspase-3, an effector of apoptosis, the expression of active form(19 kDa) of caspase-3 was increased and the increase of their activities was demonstrated by the cleavage of poly(ADP-ribose)polymerase, a substrate of caspase-3, to 85 kDa. The results indicate that extract of S. lomentaria induces the apoptosis of HL-60 cells via the down-regulation of Bc1-2 and the activation of caspases.

• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 2003년도 Annual Meeting of KSAP : International Symposium on Pharmaceutical and Biomedical Sciences on Obesity
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• pp.82-82
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• 2003

The present study was undertaken to examine the cytotoxic effect of extract of Eurya emarginata against cancer cells and to develop an anti-cancer agent using components of its leaves. The crude extract of its leaves markedly inhibited the growth of leukemia cells including HL-60. When the HL-60 cells were treated with the extract, DNA fragmentation, morphologic changes and sub-Gl hypodiploid cells were observed. Therefore, the inhibitory effect of E. emarginata on the growth of the HL-60 cells appears to arise from the induction of apoptosis. Moreover, the extract markedly reduced c-Myc expression in a time-dependent manner. Eutigoside C showing the cytotoxic effect was isolated from the leaves of E. emarginata. Eutigoside C reduced the Bcl-2 protein and mRNA levels in a time-dependent manner, whereas the Bax protein and mRNA expression levels were slightly increased. When HL-60 cells were treated with eutigoside C, the release of cytochrome C from mitochondria into the cytosol was observed. Also, the expressions of the active forms of caspase 9 and 3 were increased and the activation of caspase 3 was demonstrated by the cleavage of Poly(ADP-ribose) polymerase, a vital substrate of effector caspase. The results indicate that the eutigoside C from E. emarginata induce apoptosis of HL-60 cells via the down-regulation of Bcl-2 expression and activation of caspases.

• Biomolecules & Therapeutics
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• 제25권4호
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• pp.404-410
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• 2017

Benzylideneacetophenone derivative (1E)-1-(4-hydroxy-3-methoxyphenyl) hept-1-en-3-one (JC3) elicited cytotoxic effects on MDA-MB 231 human breast cancer cells-radiation resistant cells (MDA-MB 231-RR), in a dose-dependent manner, with an $IC_{50}$ value of $6{\mu}M$ JC3. JC3-mediated apoptosis was confirmed by increase in sub-G1 cell population. JC3 disrupted the mitochondrial membrane potential, and reduced expression of anti-apoptotic B cell lymphoma-2 protein, whereas it increased expression of pro-apoptotic Bcl-2-associated X protein, leading to the cleavage of caspase-9, caspase-3 and poly (ADP-ribose) polymerase. In addition, JC3 activated mitogen-activated protein kinases, and specific inhibitors of these kinases abrogated the JC3-induced increase in apoptotic bodies. JC3 increased the level of intracellular reactive oxygen species and enhanced oxidative macromolecular damage via lipid peroxidation, protein carbonylation, and DNA strand breakage. Considering these findings, JC3 is an effective therapy against radiation-resistant human breast cancer cells.

• Natural Product Sciences
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• 제18권1호
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• pp.16-21
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• 2012

Honokiol, a naturally occurring neolignan mainly found in Magnolia species, has been shown to have the anti-angiogenic, anti-invasive and cancer chemopreventive activities, but the molecular mechanism of actions has not been fully elucidated yet. In the present study, we investigated the effect of honokiol on the growth inhibitory activity in cultured SNU-638 human gastric cancer cells. We found that honokiol exerted potent antiproliferative activity against SNU-638 cells. Honokiol also arrested the cell cycle progression at the G0/G1 phase and induced the apoptotic cell death in a concentration-dependent manner. The cell cycle arrest was well correlated with the downregulation of Rb, cyclin D1, cyclin A, cyclin E, and CDK4 expression, and the induction of cyclin-dependent kinase inhibitor p27. The increase of sub-G1 peak by honokiol was closely related to the induction of apoptosis, which was evidenced by the induction of DNA fragmentation, the cleavage of poly(ADPribose) polymerase, and the sequential activation of caspase cascade. These findings suggest the cell cycle arrest and induction of apoptosis might be one possible mechanism of actions for the anti-proliferative activity of honokiol in human gastric cancer cell.

• Asian Pacific Journal of Cancer Prevention
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• 제15권17호
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• pp.7055-7059
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• 2014

Artemisia, as one of the largest genera in the tribe Anthemideae of the Asteraceae comprises an important part of Iranian flora. While cytotoxic and apoptotic properties have already been reported for some species of the genus there is not any report on cytotoxic effects of A. ciniformis. Petroleum ether (40-60), dichloromethane, ethyl acetate, ethanol and ethanol-water (50:50) extracts of the aerial parts of A. cinformis were subjected to cytotoxic and apoptotic evaluations on two cancer human cell lines (K562 and HL-60) and on J774 normal cells. Among multiple extracts evaluated for cytotoxicity, dichloromethane ($CH_2Cl_2$) and petroleum ether (PE) extracts were shown to possess the highest anti-proliferative effects on HL-60 and K562 cells with $IC_{50}$ values of 31.3 and $25.5{\mu}g/ml$ respectively. Apoptosis induction verified by sub-G1 peaks was seen in flow cytometry histograms. Increase in the amount of Bax protein, formation of DNA fragments, and cleavage of PARP to 24 and 89kDa sub units all confirmed induction of apoptosis by A. cinformis extracts. Taken together according to the result of the present study some extracts of A. cinformis could be considered as sources for natural cytotoxic compounds and further mechanistic and phytochemical studies are recommended to fully understand the underlying mechanisms of cnacer cell death as well as identification of responsible phytochemicals.

• Archives of Pharmacal Research
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• 제28권9호
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• pp.1047-1052
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• 2005

Two phenolic glucosides, eutigoside Band eutigoside C were isolated from the fresh leaves of Eurya emarginata. These two phenolic glucosides exerted a significant inhibitory effect on the growth of HL-60 promyelocytic leukemia cells. Furthermore, when the HL-60 cells were treated with eutigoside C, several apoptotic characteristics such as DNA fragmentation, morphologic changes, and increase of the population of sub-G1 hypodiploid cells were observed. In order to understand the mechanism of apoptosis induction by eutigoside C, we examined the changes of Bcl-2 and Bax expression levels. The eutigoside C reduced BcI-2 protein and mRNA levels, but slightly increased Bax protein and mRNA levels in a time-dependent manner. When we examined the activation of caspase-3, an effector of apoptosis, the eutigoside C increased the expression of active form (19-kDa) of caspase-3 and the increase of their activities was demonstrated by the cleavage of poly (ADP-ribose) polymerase, a substrate of caspase-3, to 85-kDa. The results suggest that the inhibitory effect of eutigoside C from E. emarginata on the growth of HL-60 appears to arise from the induction of apoptosis via the down-regulation of BcI-2 and the activation of caspase.

• 동의생리병리학회지
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• 제17권5호
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• pp.1243-1250
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• 2003

This study was designed to elucidate the synergistic cytotoxic mechanisms of the co-treatment of adriamycin and Paljinhangahm-dan in human hepatoma malignant cancer cell line, HepG2. The combination of adriamycin and the ethanol extract of Paljinhangahm-dan synergistically augmented the cytotoxicity of Adriamycin and Paljinhangahm-dan in HepG2 cells. The cytotoxicity of two drugs was revealed as apoptosis characterized by DNA fragmentaton in agarose gel electrophoresis. The apoptotic cytotoxicity of adriamycin and Paljinhangahm-dan was accompanied by the cleavage of procaspase -3 protease and PARP. Of note, anti apoptotic Bcl2 protein was obviously decreased, but Fas was dramatically increased in HepG2 cells co-treated with Adriamycin and Paljinhangahm -dan. In addition, through 2-D gel electorphoresis, we observed that the expression levels of a lot of proteins were obviously changed by the status of drug treatments. This results suggest that the synergistic cytotoxicity of the co-treatment of adriamycin and Paljinhangahm-dan might be caused by the changes of the expression levels of a lot of proteins which play pivotal roles in cell survival or death.