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Kim KW, Kim SH, Lee EY, Kim ND, Kang HS, Kim HD, Chung BS, Kang CD. Extracellular signal-regulated kinase/90-KDA ribosomal S6 kinase/nuclear factor-kappa B pathway mediates phorbol 12-myristate 13-acetate-induced megakaryocytic differentiation of K562 cells. J Biol Chem 2001; 276:13186-91. [PMID: 11278385 DOI: 10.1074/jbc.m008092200] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Two signaling pathways, the extracellular signal-regulated kinase (ERK)/mitogen-activated protein kinase (MAPK)-dependent pathway and the nuclear factor-kappaB (NF-kappaB)-dependent pathway, have been known to mediate megakaryocytic differentiation of K562 cells induced by phorbol 12-myristate 13-acetate (PMA). In this study, we examined whether 90-kDa ribosomal S6 kinase (RSK), known as a substrate of ERK/MAPK and a signal-inducible IkappaBalpha kinase, would link two pathways during the differentiation. RSK1 was activated in a time- and dose-dependent manner during the PMA-induced differentiation. Overexpression of wild-type or dominant inhibitory mutant (D205N) of RSK1 enhanced or suppressed PMA-stimulated NF-kappaB activation and megakaryocytic differentiation as shown by morphology, nonspecific esterase activity, and expression of the CD41 megakaryocytic marker, respectively. In addition, overexpression of the dominant inhibitory mutant (S32A/S36A) of IkappaBalpha inhibited PMA-stimulated and RSK1-enhanced megakaryocytic differentiation, indicating that NF-kappaB mediates a signal for megakaryocytic differentiation downstream of RSK1. PMA-stimulated activation of ERK/MAPK, RSK1, and NF-kappaB and the PMA-induced megakaryocytic differentiation were prevented by pretreatment with PD98059, a specific inhibitor of the mitogen-activated ERK kinase (MEK). Therefore, these results demonstrate that the sequential ERK/RSK1/NF-kappaB pathway mediates PMA-stimulated megakaryocytic differentiation of K562 cells.
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Speed DJ, Dickson SJ, Cairns ER, Kim ND. Analysis of paracetamol using solid-phase extraction, deuterated internal standards, and gas chromatography-mass spectrometry. J Anal Toxicol 2001; 25:198-202. [PMID: 11327352 DOI: 10.1093/jat/25.3.198] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
A rapid method for determining paracetamol (acetaminophen) in whole blood and liver tissue samples is described. Blank plus single-point calibration gives reliable quantitation at therapeutic and higher concentrations. Whole blood and liver tissue samples containing a deuterated internal standard were extracted using Bond Elut Certify columns. Butyl derivatives were formed using n-iodobutane and tetramethyl ammonium hydroxide under mild conditions and were extracted into ethyl acetate as a cleanup step. Recovery was better than 90%, and sample preparation time was less than 2 h. Gas chromatograph run time was less than 20 min. SIM of two ion pairs formed by electron impact ionization resulted in intraday coefficients of variation (CV) less than 3.03% (7.48% in liver) and interday CVs less than 8.93% (for midtherapeutic concentrations in whole blood). Linearity was observed from subtherapeutic to high, fatal levels. This method has been applied to forensic cases and has significantly reduced analytical time while improving casework quality. Results of a case study involving paracetamol are given.
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Im EO, Choi YH, Paik KJ, Suh H, Jin Y, Kim KW, Yoo YH, Kim ND. Novel bile acid derivatives induce apoptosis via a p53-independent pathway in human breast carcinoma cells. Cancer Lett 2001; 163:83-93. [PMID: 11163111 DOI: 10.1016/s0304-3835(00)00671-6] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
We have compared the anti-proliferative effects of ursodeoxycholic acid (UDCA), chenodeoxycholic acid (CDCA) and their derivatives, HS-1183, HS-1199 and HS-1200, on MCF-7 (wild-type p53) and MDA-MB-231 (mutant p53) cells. While UDCA and CDCA exhibited no significant effect, their novel derivatives inhibited the proliferation of both cell lines in a concentration-dependent manner, concomitant with apoptotic nuclear changes and the increase of a sub-G1 population and DNA fragmentation. Furthermore, we also observed an increase in the ratio of pro-apoptotic protein Bax to anti-apoptotic protein Bcl-2 and cleavages of lamin B and poly(ADP-ribose) polymerase (PARP) in MCF-7 and MDA-MB-231 cells. Cell cycle related proteins, cyclin D1 and D3, as well as retinoblastoma protein (pRb) were down-regulated, while the level of cyclin-dependent kinase inhibitor p21(WAF1/CIP1) was increased in both cancer cells after treatment with novel bile acids. These findings suggest that these cytotoxic effects of novel bile acid derivatives on human breast carcinoma cells were mediated via apoptosis through a p53-independent pathway.
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Lee JW, Lee B, Kim ND. Synthesis of 2-(allylthio)pyrazines as a novel cancer chemopreventive agent. Arch Pharm Res 2001; 24:16-20. [PMID: 11235806 DOI: 10.1007/bf02976487] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
2-(Allylthio)pyrazine derivatives were designed as a novel cancer chemopreventive agent that functions through selective inhibtion of cytochrome P-450 and induction of phase II enzymes involved in the detoxification of carcinogens. A practical preparation method of 2-(allylthio) pyrazine derivatives was established by the reaction of 2-mercaptopyrazine and allylbromides in the presence of a catalytic antioxidant, DABCO (1,4-diazabicyclo[2,2,2] octane), in dimethylformamide at below 50 degrees C.
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Kim WY, Kim JM, Han SB, Lee SK, Kim ND, Park MK, Kim CK, Park JH. Steaming of ginseng at high temperature enhances biological activity. JOURNAL OF NATURAL PRODUCTS 2000; 63:1702-1704. [PMID: 11141123 DOI: 10.1021/np990152b] [Citation(s) in RCA: 300] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The present study was performed to evaluate the effect of steaming ginseng at a temperature over 100 degrees C on its chemical constituents and biological activities. Raw ginseng was steamed at 100, 110, and 120 degrees C for 2 h using an autoclave. The ginseng steamed at 120 degrees C was more potent in its ability to induce endothelium-dependent relaxation. Steaming the raw ginseng at 120 degrees C also remarkably increased the radical-scavenging activity. Ginsenosides F(4), Rg(3), and Rg(5), which were not present in raw ginseng, were produced after steaming. Ginsenosides Rg(3) and Rg(5) were the most abundant ginsenosides in the ginseng steamed at 120 degrees C, accounting for 39% and 19% of all ginsenosides, respectively.
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Choi SH, Kang HK, Im EO, Kim YJ, Bae YT, Choi YH, Lee KH, Chung HY, Chang HK, Kim ND. Inhibition of cell growth and telomerase activity of breast cancer cells in vitro by retinoic acids. Int J Oncol 2000; 17:971-6. [PMID: 11029500 DOI: 10.3892/ijo.17.5.971] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The effects of retinoic acid (RA) and its analogs, all-trans RA, 9-cis RA and 13-cis RA, were investigated in human breast cancer MCF-7 cells and immortalized breast epithelial cell line MCF-10A. RA inhibited the telomerase activity of MCF-7 cells in a wide range of concentrations. RA at 10 microM also inhibited the growth of MCF-7 cells in a time-dependent manner. However, no significant growth inhibition was found between untreated control and RA-treated MCF-10A cells. Moreover, a marked inhibition of telomerase activity by RA was detected early in MCF-7 cells (after 24 h of RA treatment), which was preceded by a reduction of hTERT mRNA expression (after 12 h of RA treatment). However, MCF-10A cells showed a reduction of telomerase activity and down-regulation of hTERT after 4 days of RA treatment. Simultaneous changes in hTERT mRNA expression and telomerase activity were found for MCF-10A cells. The expressions of hTR and hTEP1 telomerase component genes were not changed after RA treatment. These results indicate that the anti-breast cancer activity of RA could be mediated by its ability to down-regulate the expression of hTERT telomerase gene.
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Speed DJ, Dickson SJ, Cairns ER, Kim ND. Analysis of six anticonvulsant drugs using solid-phase extraction, deuterated internal standards, and gas chromatography-mass spectrometry. J Anal Toxicol 2000; 24:685-90. [PMID: 11110022 DOI: 10.1093/jat/24.8.685] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
A rapid method for simultaneously determining the anticonvulsant drugs carbamazepine, ethosuximide, phenobarbitone, phenytoin, primidone, and valproic acid is described. Blank plus single-point calibration gives reliable quantitation from therapeutic to high fatal concentrations, except for ethosuximide, for which it gives semiquantitative results. Whole blood and liver tissue samples containing deuterated internal standards were extracted using Bond Elut Certify columns. Butyl derivatives were formed using n-iodobutane and TMAH under mild conditions and were extracted into ethyl acetate as a cleanup step. Recoveries were greater than 50%, except for valproic acid (42%). Sample preparation time was less than 2 h, and the GC run time was less than 20 min per injection. At least two ion pairs formed by electron impact ionization were monitored for each drug. Intraday CVs were less than 6.28% (4.20%) and interday CVs less than 14.1% (for midtherapeutic concentrations in blood [liver], except for ethosuximide). Linearity was observed from subtherapeutic to high fatal levels for all drugs. This method has been applied to forensic cases and has significantly reduced analytical time while improving case-work quality. Results of a case study involving anticonvulsant drugs are given.
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Kim ND, Oberley TD, Yasukawa-Barnes J, Clifton KH. Stem cell characteristics of transplanted rat mammary clonogens. Exp Cell Res 2000; 260:146-59. [PMID: 11010819 DOI: 10.1006/excr.2000.5013] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Rat mammary glands contain a subpopulation of clonogenic epithelial cells with large proliferation and differentiation potentials. When transplanted, the clonogens in monodispersed rat mammary epithelial cell suspensions give rise to either alveolar units (AUs) or ductal units (DUs) depending on the nature of the hormonal milieu in the graft recipient. Clonogens are also the primary cells of origin of mammary cancer following exposure to ionizing radiation or chemical carcinogens. Given the other stem cell characteristics of mammary clonogens, it would be expected that the primary AUs and DUs to which they give rise when grafted and hormonally stimulated (a) would be derived from the same clonogenic cell subpopulation, (b) would contain all of the functionally differentiated cell types of homologous parts of comparably stimulated mammary glands in situ, and (c) would also contain clonogen subpopulations capable when subtransplanted of giving rise to secondary AUs and DUs of similar cell composition. The current experiments were designed to test these expectations. The data are discussed in the context of results of previous studies with this and other experimental models. The results further support the conclusion that rat mammary clonogens are multipotent mammary stem cells.
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Baek JH, Jang JE, Kang CM, Chung HY, Kim ND, Kim KW. Hypoxia-induced VEGF enhances tumor survivability via suppression of serum deprivation-induced apoptosis. Oncogene 2000; 19:4621-31. [PMID: 11030151 DOI: 10.1038/sj.onc.1203814] [Citation(s) in RCA: 134] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Low oxygen and nutrient depletion play critical roles in tumorigenesis, but little is known about how they interact to produce tumor survival and tumor malignancy. In the present study, we investigated the mechanism underlying hypoxia-modulated apoptosis of serum-deprived HepG2 cells. Our results showed that hypoxia blocked the apoptosis, which was accompanied with decreased Bax/Bcl-2 ratio, inhibited cytochrome c release, and reduced caspase-3 activity. More importantly, increased expressions of VEGF and its receptor-2 (KDR) under hypoxic/serum-deprived condition suggest that VEGF may act as a survival factor in a self-promoting manner. Data were further supported by results that recombinant human VEGF (rhVEGF) suppressed the serum deprivation-induced apoptosis, and anti-VEGF neutralizing antibody block anti-apoptotic activity of hypoxia. In addition, inhibitors of receptor tyrosine kinase blocked antiapoptosis of hypoxia. Our study further showed that rhVEGF or hypoxia induced ERK phosphorylation in serum-deprived cells, and that a specific inhibitor of MAPK/ERK, PD98059 eliminated the anti-apoptotic activity of rhVEGF or hypoxia by increasing Bax/Bcl-2 ratio and caspase-3 activity. Our data led us to conclude that induction of ERK phosphorylation and decrease of Bax/Bcl-2 ratio by rhVEGF implies that hypoxia-induced VEGF prevents apoptosis of serum-deprived cells by activating the MAPK/ERK pathway. Taken together, we propose that hypoxia enhances survival of nutrient-depleted tumor cells by reducing susceptibility to apoptosis, which consequently leads to tumor malignancy.
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MESH Headings
- Apoptosis/drug effects
- Apoptosis/physiology
- Autocrine Communication
- Carcinoma, Hepatocellular/metabolism
- Carcinoma, Hepatocellular/pathology
- Caspase 3
- Caspases/metabolism
- Cell Hypoxia/physiology
- Cell Survival
- Culture Media, Serum-Free/pharmacology
- Cytochrome c Group/metabolism
- Endothelial Growth Factors/biosynthesis
- Endothelial Growth Factors/genetics
- Endothelial Growth Factors/pharmacology
- Endothelial Growth Factors/physiology
- Enzyme Inhibitors/pharmacology
- Flavonoids/pharmacology
- Gene Expression Regulation, Neoplastic/drug effects
- Genes, bcl-2
- Humans
- Liver Neoplasms/pathology
- Lymphokines/biosynthesis
- Lymphokines/genetics
- Lymphokines/pharmacology
- Lymphokines/physiology
- MAP Kinase Signaling System/drug effects
- MAP Kinase Signaling System/physiology
- Mitochondria, Liver/enzymology
- Mitogen-Activated Protein Kinase 3
- Mitogen-Activated Protein Kinases/antagonists & inhibitors
- Mitogen-Activated Protein Kinases/physiology
- Neoplasm Proteins/biosynthesis
- Neoplasm Proteins/genetics
- Neoplasm Proteins/physiology
- Proto-Oncogene Proteins/biosynthesis
- Proto-Oncogene Proteins/genetics
- Proto-Oncogene Proteins c-bcl-2/biosynthesis
- Receptor Protein-Tyrosine Kinases/antagonists & inhibitors
- Receptor Protein-Tyrosine Kinases/biosynthesis
- Receptor Protein-Tyrosine Kinases/drug effects
- Receptor Protein-Tyrosine Kinases/genetics
- Receptor Protein-Tyrosine Kinases/physiology
- Receptors, Growth Factor/biosynthesis
- Receptors, Growth Factor/drug effects
- Receptors, Growth Factor/genetics
- Receptors, Growth Factor/physiology
- Receptors, Vascular Endothelial Growth Factor
- Recombinant Fusion Proteins/pharmacology
- Tumor Cells, Cultured/drug effects
- Tumor Cells, Cultured/metabolism
- Vascular Endothelial Growth Factor A
- Vascular Endothelial Growth Factors
- bcl-2-Associated X Protein
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Yoon HS, Moon SC, Kim ND, Park BS, Jeong MH, Yoo YH. Genistein induces apoptosis of RPE-J cells by opening mitochondrial PTP. Biochem Biophys Res Commun 2000; 276:151-6. [PMID: 11006098 DOI: 10.1006/bbrc.2000.3445] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Although previous studies demonstrated that genistein-induced apoptosis of various cell types including RPE-J cells, the involvement of mitochondrial events in such types of apoptosis has not been demonstrated to date. In this investigation of genistein-induced apoptosis of RPE-J cells, genistein induced the reduction of the mitochondrial membrane potential and the release of cytochrome c to cytosol. A mitochondrial permeability transition pore (PTP) blocker bongkrekic acid prevented the reduction of the mitochondrial membrane potential and cytochrome c release, and consequently abolished caspase-3 activation, nuclear condensation, and DNA fragmentation. On the other hand, zVAD-fmk did not inhibit the mitochondrial event such as the reduction of the mitochondrial membrane potential and cytochrome c release although it prevented caspase-3 activation, nuclear condensation, and DNA fragmentation. Taken together, genistein induces apoptosis of RPE-J cells by opening the mitochondrial PTP, and the mitochondrial event in this type of apoptosis is caused independently of caspase.
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Choi YH, Baek JH, Yoo MA, Chung HY, Kim ND, Kim KW. Induction of apoptosis by ursolic acid through activation of caspases and down-regulation of c-IAPs in human prostate epithelial cells. Int J Oncol 2000; 17:565-71. [PMID: 10938399] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023] Open
Abstract
Previous results indicate that ursolic acid (UA), a pentacyclic triterpene acid, has strong cytotoxic activity and effectively induces growth arrest in a variety of systems. However, the molecular mechanisms underlying anti-tumorigenic or chemopreventive activities of UA are poorly understood. To further determine the mechanism of UA, we investigated the effects of UA on the growth of human prostate epithelial cells. Upon treatment with UA, a concentration-dependent inhibition of cell viability was observed and cells developed many of the hallmark features of apoptosis, including condensation of chromatin and DNA fragmentation. These apoptotic effects of UA were accompanied by proteolytic cleavage of specific target proteins such as PARP, beta-catenin and Rad51 proteins suggesting the possible involvement of caspases. Western blotting and in vitro assay demonstrated that processing/activation of at least four caspases (caspase-1, -3, -8 and -9) accompanies the generation of UA-mediating apoptotic cell death. In addition to activation of caspases, the down-regulation of c-IAPs family proteins, which suppress the apoptotic death signaling by the direct inhibition of activated caspases, was also observed. However, UA did not affect both the level of p53 expression and the alteration of the balance between Bcl-2 and Bax expression. These data suggest that apoptotic signals evoked by UA treatment may converge caspases activation through down-regulation of c-IAPs family and without mitochondrial dysfunction.
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Choi YH, Baek JH, Yoo MA, Chung HY, Kim ND, Kim KW. Induction of apoptosis by ursolic acid through activation of caspases and down-regulation of c-IAPs in human prostate epithelial cells. Int J Oncol 2000. [DOI: 10.3892/ijo.17.3.565] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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38
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Kim DK, Baek JH, Kang CM, Yoo MA, Sung JW, Chung HY, Kim ND, Choi YH, Lee SH, Kim KW. Apoptotic activity of ursolic acid may correlate with the inhibition of initiation of DNA replication. Int J Cancer 2000; 87:629-36. [PMID: 10925354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
Ursolic acid (UA), a pentacyclic triterpene acid, has been reported to exhibit anti-tumor activity. In this study, we investigated the pro-apoptotic effect of UA on HepG2 human hepatoblastoma cells. Treatment with UA decreased the viability of HepG2 cells in a concentration- and time-dependent manner. Furthermore, 30 microM of UA induced DNA fragmentation and subdiploid cells and enhanced the release of cytochrome c and the activation of caspase-3. These results suggest that UA induces cell death through apoptosis, which may be mediated by cytochrome c-dependent caspase-3 activation. In addition, cell-cycle analysis revealed that UA-treated cells were arrested predominantly in the G(0) and G(1) phases with a concomitant decrease in the cell population of S phase. Moreover, expression of p21(WAF1), a cell-cycle regulator, was increased by UA, indicating that p21(WAF1) might mediate UA-induced cell-cycle arrest. However, UA markedly inhibited SV40 DNA replication in the initiation stage in vitro and significantly reduced the DNA cleaving of topoisomerase I and the ssDNA binding activity of replication protein A. These results indicate that the inhibition of DNA replication by UA may result from blockade of the establishment of the replication fork during initiation stage, consequently contributing to UA-induced cell-cycle arrest. Taken together, we suggest that UA-induced cell-cycle arrest may be mediated by inhibition of DNA replication and the increase of p21(WAF1) expression, which induces the release of cytochrome c and the activation of caspase-3, leading to apoptosis of HepG2 cells.
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Kim DK, Baek JH, Kang CM, Yoo MA, Sung JW, Chung HY, Kim ND, Choi YH, Lee SH, Kim KW. Apoptotic activity of ursolic acid may correlate with the inhibition of initiation of DNA replication. Int J Cancer 2000. [PMID: 10925354 DOI: 10.1002/1097-0215(20000901)87:5<629::aid-ijc2>3.0.co;2-p] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Ursolic acid (UA), a pentacyclic triterpene acid, has been reported to exhibit anti-tumor activity. In this study, we investigated the pro-apoptotic effect of UA on HepG2 human hepatoblastoma cells. Treatment with UA decreased the viability of HepG2 cells in a concentration- and time-dependent manner. Furthermore, 30 microM of UA induced DNA fragmentation and subdiploid cells and enhanced the release of cytochrome c and the activation of caspase-3. These results suggest that UA induces cell death through apoptosis, which may be mediated by cytochrome c-dependent caspase-3 activation. In addition, cell-cycle analysis revealed that UA-treated cells were arrested predominantly in the G(0) and G(1) phases with a concomitant decrease in the cell population of S phase. Moreover, expression of p21(WAF1), a cell-cycle regulator, was increased by UA, indicating that p21(WAF1) might mediate UA-induced cell-cycle arrest. However, UA markedly inhibited SV40 DNA replication in the initiation stage in vitro and significantly reduced the DNA cleaving of topoisomerase I and the ssDNA binding activity of replication protein A. These results indicate that the inhibition of DNA replication by UA may result from blockade of the establishment of the replication fork during initiation stage, consequently contributing to UA-induced cell-cycle arrest. Taken together, we suggest that UA-induced cell-cycle arrest may be mediated by inhibition of DNA replication and the increase of p21(WAF1) expression, which induces the release of cytochrome c and the activation of caspase-3, leading to apoptosis of HepG2 cells.
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Kim SH, Kang KW, Kim KW, Kim ND. Procyanidins in crataegus extract evoke endothelium-dependent vasorelaxation in rat aorta. Life Sci 2000; 67:121-31. [PMID: 10901280 DOI: 10.1016/s0024-3205(00)00608-1] [Citation(s) in RCA: 113] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The extract of Crataegus, a mixture of flavonoids and procyanidins extracted from hawthorn, Crataegus oxyacantha, L. and C. monogyna Jacq., relaxed vascular tone or increased production of cyclic GMP in the rat aorta, but flavonoid components of Crataegus extract, hyperoside, rutin and vitexin, did not affect the vascular tone. The aim of the present study was to characterize the endothelium-dependent relaxation elicited by procyanidins fractionated from Crataegus extract in isolated rat aorta. Procyanidins caused endothelium-dependent relaxation which was associated with the production of cyclic GMP. Both responses to these procyanidins were inhibited by methylene blue or N(G)-nitro-L-arginine, but not by indomethacin. Relaxation in response to procyanidins was not affected by atropine, diphenhydramine, [D-Pro2,D-Trp7,9]substance P, propranolol, nifedipine, verapamil and glibenclamide, but were markedly reduced by tetraethylammonium. These findings showed that procyanidins in Crataegus extract may be responsible for the endothelium-dependent nitric oxide-mediated relaxation in isolated rat aorta, possibly via activation of tetraethylammonium-sensitive K+ channels.
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Lee JH, Ham YA, Choi SH, Im EO, Jung JH, Im KS, Kim DK, Xu Y, Wang MW, Kim ND. Activity of crude extract of Rubus crataegifolius roots as a potent apoptosis inducer and DNA topoisomerase I inhibitor. Arch Pharm Res 2000; 23:338-43. [PMID: 10976580 DOI: 10.1007/bf02975444] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
The effects of methanol extract of Rubus crategifolius roots and its solvent fractions were investigated on the proliferation of MCF-7 human breast carcinoma cells. The methanol extract inhibited the proliferation of MCF-7 cells in a concentration dependent manner. Moreover, their methanol soluble (W-M) fraction had the greatest inhibitory effect on the growth of MCF-7 cells. To evaluate whether the W-M fraction affects on the cell cycle of MCF-7 cells, cells treated with this fraction were analyzed with flow cytometry. The W-M fraction increased G0/G1 phase after 24 h-treatment and induced apoptosis after 48 h-treatment. The hallmark of apoptosis, DNA fragmentation, also appeared by W-M fraction after 48 h-treatment. Furthermore, the methanol extract and its W-M fraction inhibited the activity of the topoisomerase I enzyme in the relaxation assay. From these results, their W-M fraction as well as methanol extract of R. crategifolius roots are necessary for further studies as a potent inhibitor of the growth of cancer cells.
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Caldwell JP, Henderson W, Kim ND. ABTS: a safe alternative to DAB for the enhancement of blood fingerprints. J Forensic Sci 2000; 45:785-94. [PMID: 10914571] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
The use of 2,2'-azino-di-[3-ethylbenzthiazolinesulfonate(6)] diammonium salt (ABTS) for the enhancement of fingerprints in blood has been investigated. Optimal pH conditions and H2O2 concentrations have been determined using UV/Vis spectroscopy. ABTS is an effective and safe noncarcinogenic (though more expensive) alternative to the presently used 3,3'-diaminobenzidine (DAB) for the development of blood fingerprints, especially on porous surfaces. The bright green color of the oxidized ABTS is an advantage on certain colored surfaces where the dark brown color of DAB does not stand out well from the background. Development with ABTS does not interfere with subsequent DAB treatment, making ABTS a "nothing-to-lose" reagent. ABTS can be used after ninhydrin treatment, but the reverse is not the case.
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43
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Ahn JR, Lee SS, Kim ND, Min JH, Hwang CG, Chung JW. Observation of disorder-induced 2D mott-hubbard states of the alkali-earth metal (Mg,Ba)-adsorbed Si(111) surface. PHYSICAL REVIEW LETTERS 2000; 84:1748-1751. [PMID: 11017616 DOI: 10.1103/physrevlett.84.1748] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/1999] [Indexed: 05/23/2023]
Abstract
We report evidence of a disorder-driven Mott-Hubbard-type localization on the alkali-earth metal (AEM) (Mg,Ba)-adsorbed Si(111)-(7x7) surface. The clean metallic Si(111) surface is found to undergo a two-dimensional (2D) metal-insulator transition as randomly distributed AEM adsorbates cause disorder on the surface. A well-defined electron-energy-loss peak unique to the insulating phase is attributed to an interband excitation between the split Hubbard bands originated from a metallic surface band at Fermi energy. A quantitative analysis of the loss peak reveals that the AEM-induced insulating surfaces are of a Mott-Hubbard type driven essentially by disorder.
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Jung SH, Kwak SJ, Kim ND, Lee SU, Lee CO. Stereochemical requirement at 4-position of 4-phenyl-1-arylsulfonylimidazolidinones for their cytotoxicities. Arch Pharm Res 2000; 23:35-41. [PMID: 10728654 DOI: 10.1007/bf02976463] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
In order to investigate the stereochemical requirements of planar structure at 4-position of 4-phenyl-1-arylsulfonylimidazolidinones (1) for their cytoxicities against human cancer cell lines, the size, the distance from imidazolidinone ring, and the conformation of this moiety were variegated. Replacement of phenyl moiety with naphthyl in compounds 2 and 3 or benzyl moiety in compound 4 sharply reduced activity of 1. Conformational restriction on phenyl ring in compound 5 also resulted in the loss of activity of 1. Therefore, phenyl moiety without any substituents directly attached to imidazolidinone ring of 1 should be considered as an essential pharmacophore for this analog.
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Park BS, Kim GC, Back SJ, Kim ND, Kim YS, Kim SK, Jeong MH, Lim YJ, Yoo YH. Murine bone marrow-derived mast cells exhibit evidence of both apoptosis and oncosis after IL-3 deprivation. Immunol Invest 2000; 29:51-60. [PMID: 10709846 DOI: 10.3109/08820130009105144] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
IL-3 deprivation has been reported to induce apoptosis of bone marrow-derived mast cells. In order to evaluate this type of cell death further, we employed trypan blue and propidium iodide stainings, photometric enzyme immunoassay, fluorescence measurement of caspase-3, DNA electrophoresis, flow cytometry and transmission electron microscopy. In this experiment, although several evidences supporting apoptosis were demonstrated some findings were not consistent with typical apoptosis. On the other hand, electron microscopical observation demonstrated that most cells from all the time phases after IL-3 deprivation showed the morphology of typical oncosis, i.e. cell swelling, disintegration of ultrastructure and subsequent karyolysis. Only a small number of cells from the later time phases showed apoptotic morphology. We here suggest that BMMCs undergo both apoptosis and oncosis after IL-3 deprivation and that the dominant type of prelethal change is oncosis in all time phases, although apoptosis also plays a partial role in the late time phases.
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Kim DK, Lee JR, Kim A, Lee S, Yoo MA, Kim KW, Kim ND, Suh H. Inhibition of initiation of simian virus 40 DNA replication in vitro by the ursodeoxycholic acid and its derivatives. Cancer Lett 1999; 146:147-53. [PMID: 10656619 DOI: 10.1016/s0304-3835(99)00251-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
In this study, the effects of the ursodeoxycholic acid (UDCA), and its derivatives, on DNA replication were examined using simian virus (SV40) DNA replication in vitro. We found that UDCA and its derivatives inhibited SV40 DNA replication, and predominantly inhibited the initiation stage of DNA replication. UDCA and its derivatives inhibited the DNA cleavage by topoisomerase I (topo I). Among them, HS-1183 significantly reduced the activity of topo I. UDCA, at 100 microM, significantly reduced polymerase alpha-primase (pol alpha-primase) activity, but HS-1030 and HS-1183 showed a weak inhibitory effect. The ssDNA binding activity of replication protein A (RPA) was little affected by UDCA and HS-1030, but was weakly inhibited by HS-1183. Based on their properties, we suggest that UDCA and its derivatives might inhibit some molecules that is required to establish replication forks during the initiation reaction and their cytotoxicity might be related to the inhibitory effect they have on this fundamental cellular process.
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Park MT, Cha HJ, Jeong JW, Kim SI, Chung HY, Kim ND, Kim OH, Kim KW. Glucocorticoid receptor-induced down-regulation of MMP-9 by ginseng components, PD and PT contributes to inhibition of the invasive capacity of HT1080 human fibrosarcoma cells. Mol Cells 1999; 9:476-83. [PMID: 10597035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/14/2023] Open
Abstract
We examined the effects of the purified ginseng components, panaxadiol (PD) and panaxatriol (PT), on the expression of matrix metalloproteinase-9 (MMP-9) in highly metastatic HT1080 human fibrosarcoma cell line. A significant down-regulation of MMP-9 by PD and PT was detected by Northern blot analysis. However, the expression of MMP-2 was not changed by treatment with PD and PT. Quantitative gelatin based zymography confirmed a markedly reduced expression of MMP-9, but not MMP-2 in the treatment of PD and PT. To investigate whether the reduced level of MMP-9 by PD and PT affects the invasive capacity of HT1080 cells, we conducted an in vitro invasion assay with PD and PT treated cells. The results of the in vitro invasion assay revealed that PD and PT reduced tumor cell invasion through a reconstituted basement membrane in the transwell chamber. Because of the similarity of chemical structure between PD, PT and dexamethasone (Dexa), a synthetic glucocorticoid, we investigated whether the down-regulation of MMP-9 by PD and PT were mediated by the nuclear translocation of glucocorticoid receptor (GR). Increased GR in the nucleus of HT1080 human fibrosarcoma cells treated by PD and PT was detected by immunocytochemistry. Western blot and gel retardation assays confirmed the increase of GR in the nucleus after treatment with PD and PT. These results suggest that GR-induced down-regulation of MMP-9 by PD and PT contributes to reduce the invasive capacity of HT1080 cells.
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Kong G, Lee SJ, Kim HJ, Surh YJ, Kim ND. Induction of granulocytic differentiation in acute promyelocytic leukemia cells (HL-60) by 2-(allylthio) pyrazine. Cancer Lett 1999; 144:1-8. [PMID: 10503871 DOI: 10.1016/s0304-3835(99)00115-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Induction of hematopoietic differentiation in human promyelocytic leukemia cells (HL-60) by new synthetic drugs or natural products has recently been recognized as a new strategy in the identification and testing of potential cancer chemopreventive and/or chemotherapeutic agents. 2-(Allythio) pyrazine (2-AP) is a pyrazine derivative of allysulfide, which has been suggested to be a potential cancer chemopreventive agent in previous in vivo and in vitro experiments. In the present study, we have investigated the inducing effect of granulocytic differentiation in HL-60 cells by 2-AP. Treatment of HL-60 cells with various concentrations of 2-AP (1-100 microM) for 7 days showed the induction of granulocytic differentiation following both morphological examination and NBT (nitroblue tetrazolium) testing (up to 40 and 52%, respectively). The expressions of bcl-2 and c-myc were down-regulated during granulocytic differentiation of HL-60 cells (up to 40%). The immunoblots for G1 cyclins in the G1-S phase transition (cyclin D1 and E) showed a progressive decrease of their expressions in both concentration- and time-dependent manners (up to 30 and 50%, respectively). These results suggest that 2-AP could induce the differentiation of HL-60 cells and might have potent cancer chemoprevention and/or chemotherapy roles in human leukemias.
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Lee E, Kong G, Lee SJ, Kim ND, Surh YJ. 2-(allylthio)pyrazine suppresses the growth and proliferation of human promyelocytic leukemia (HL-60) cells via induction of apoptosis. Anticancer Res 1999; 19:4073-80. [PMID: 10628356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Abstract
Apoptosis or programmed cell death is a highly organized physiologic process of not only maintaining homeostasis but also selectively eliminating damaged or abnormal cells. Apoptotic destruction of predisposed cells may reduce the proportion of cells available for malignant progression. Thus, pharmacologic manipulation of apoptotic pathway is regarded as a novel strategy in cancer chemoprevention as well as therapy. 2-(Allylthio)pyrazine (2-AP), a pyrazine derivative of allylsulfide synthesized for use as a chemoprotective agent, has been shown to protect against experimental carcinogenesis and mutagenesis. The present study examined the capability of 2-AP to induce apoptosis in cultured human promyelocytic leukemia (HL-60) cells. Treatment of HL-60 cells with 2-AP led to suppression of viability and proliferation in a concentration-dependent manner. Microscopic examination of the treated cells revealed typical morphological features of apoptosis, such as nuclear fragmentation and chromatin condensation. Furthermore, cells treated with 2-AP exhibited internucleosomal DNA fragmentation. Flow cytometric analysis of HL-60 cells exposed to 2-AP showed appearance of a distinct peak representing the subdiploid cell population. 2-AP treatment decreased the ratio of anti-apoptotic Bcl-2 to the death stimulating protein Bax, which may account for the molecular basis of apoptosis-inducing activity of this chemopreventive organosulfur derivative.
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Ha TG, Mar WC, Kim SG, Surh YJ, Kim ND. Enhancement of biliary excretion of aflatoxin B(1) and suppression of hepatic ornithine decarboxylase activity by 2-(allylthio)pyrazine in rats. Mutat Res 1999; 428:59-67. [PMID: 10517979 DOI: 10.1016/s1383-5742(99)00032-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
2-(Allylthio)pyrazine (2-AP), a synthetic pyrazine derivative with an allylsulfur moiety, has protective effects against chemically-induced hepatic toxicity. Previous studies have shown that 2-AP significantly reduces the formation of preneoplastic foci in rats exposed to aflatoxin B(1) (AFB(1)). The present study was designed to determine whether 2-AP could increase the biliary excretion of metabolites of AFB(1) in rats treated with this carcinogen and whether the agent could alter the activity of ornithine decarboxylase (ODC), which is considered to be associated with tumor promotion. Rats were pretreated with 2-AP (p.o.) at a daily dose of 50 mg/kg for 5 consecutive days. AFB(1) (5 mg/kg) was administered intraperitoneally 2 h after the last dose of 2-AP. Amounts of principal AFB(1) metabolites, AFB(1)-glutathione and a glucuronide conjugate secreted in bile juice was increased by 56 and 50%, respectively, after the 2-AP treatment. Levels of radiolabelled AFB(1) covalently bound to calf thymus DNA catalyzed by microsomes obtained from 2-AP-treated rats (10 and 50 mg/kg, for 5 days) were reduced by 47 to 66%. ODC activity in AFB(1)-treated rats was determined by the three-step medium-term hepatocarcinogenesis assay. Rats were treated with 2-AP at the daily doses of 10, 25 and 50 mg/kg for 16 consecutive days. During this period, four repeated doses of AFB(1) (1.0 mg/kg) were given to the animals. Rats were then subjected to two-third partial hepatectomy, followed by administration of phenobarbital. 2-AP inhibited AFB(1)-induced ODC activity by 40 to 66%, as determined at the 44th day. Inhibition of AFB(1)-induced ODC activity by 2-AP in conjunction with acceleration of AFB(1) elimination through metabolic conjugation may contribute to its chemopreventive effects against this carcinogen.
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