• 약학회지
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• 제53권4호
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• pp.222-227
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• 2009

Human topoisomerase I (Topo I) plays a pivotal role in cell replication, transcription and repair and, therefore, is an important anti-cancer target. 20S-camptothecin (CPT) is a representative Topo I inhibitor. Compounds belonging to CPT family inhibit the religation step of Topo I-DNA by binding to the DNA cleavage site. Computational docking studies with Surflex-Dock were carried out to investigate the binding modes between Topo I-DNA binary complex structure and the ligand such as 20S-CPT and 9,10-substituted 20S-CPT analogues. The docking results demonstrated that most of the compounds with $IC_{50}$ value under $0.5{\mu}M$ intercalated exactly between the -1 and +1 DNA bases, deeply toward the cleavage site. The complex was stabilized by hydrogen-bonding and hydrophobic interactions with both the enzyme and the DNA. The compounds with $IC_{50}$ value above $0.5{\mu}M$ were poorly docked and did not intercalate. In addition, the docking results confirmed the overall correlation between the $IC_{50}$ values and docking scores, indicating the possible use of the modeling for the prediction of biological activity and design of potential inhibitors.

• 약학회지
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• 제53권4호
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• pp.228-234
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• 2009

Topoisomerase I (Topo I) participates in the DNA replication, transcription, and repair. Binding of Topo I inhibitor to the Topo I-DNA cleavage complex forms stabilized ternary complex which blocks DNA religation and ultimately causes cell death. Camptothecin (CPT) and its derivatives have been among the most effective anticancer drugs by inhibition of topo I. However, efforts to synthesize non-CPT drugs have been actively going on because the CPT derivatives have several limitations such as poor solubility, short half-life, and side effects. As an indenoisoquinoline, NSC314622 is not as potent as CPT, but its chemical stability and slower reversibility of the cleavage complex made it a good lead compound. Recently, a series of indenoisoquinoline analogues were synthesized with substituted dimethoxy or methylenedioxy on the aromatic ring and alkylamino on the lactam nitrogen. Some of them showed quite good Topo I inhibitory activity. Using the computer docking program, Surflex-Dock, indenoisoquinoline analogues were docked into the human Topo I-DNA cleavable complex. The docking results showed that the compounds with activity better than NSC314622 intercalated between the -1 and +1 base pairs at the cleavage site, but those with little or no activities did not appear to intercalate. These results could be useful to design new Topo I inhibitors improved than CPT.

• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 1996년도 춘계학술대회
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• pp.174-174
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• 1996

Extract of Pulsatilla Koreana (SB-31) showed promising antitumor activity in vitro (J. Kor Cancer Asso 26:959-963, 1994). We studied the mechanism of cytotoxicity of SB-31. HL-60 cells were cocultivated with various concentrations of SB-31 for 5 hours. The DNAs from HL-60 cells exposed to SB-31 showed the ladder pattern typical of apoptosis. Effect of SB-31 on topoisomerase I activity was determined by slight modification of the method by E. Aflalo(1994). The pBR322 DNA showed dose-dependent increase of R-Form DNA upon incubation with SB-31. The topoisomerase Ⅰ-like activity (Increase of R-Form DNA) was accentuated with higher dose of SB-31. It is postulated that SB-31, which is a fermentation product of Pulsatilla koreana and which loses its activity when kept in ambient temperature for more than 96 hours, may contain topoisomerase Ⅰ-like activity and the enhanced excessive single strand breaks induced by 55-31 may result in apoptosis.

• Natural Product Sciences
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• 제17권3호
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• pp.245-249
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• 2011

Eight compounds, squalene (1), friedelin (2), ${\beta}$-sitosterol (3), ${\beta}$-sitosterol-3-O-glucoside (4), ${\alpha}$-tocopherol (5), betulinic acid (6), trilinolein (7) and 1-O-(9Z,12Z-Octadecadienoyl)-3-nonadecanoyl glycerol (8), were isolated from the barks of Tilia amurensis. Their chemical structures were identified by comparing their physicochemical and spectral data with those published in the literature. These isolated compounds were examined for their inhibitory activities against topoisomerase I and II. Compound 7 showed significant inhibition of DNA topoisomerase I and II activities, with percent decreases in activity of 87 and 95%, respectively at a concentration of $100\;{\mu}M$. Compound 6 exhibited cytotoxicity against the human colon adenocarcinoma cell line (HT-29), the human breast adenocarcinoma cell line (MCF-7) and the human liver hepatoblastoma cell line (HepG-2), with $IC_{50}$ values of 20, 59 and $16\;{\mu}M$, respectively.

• 통합자연과학논문집
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• 제7권4호
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• pp.241-252
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• 2014

A series of N-benzoylated ligands incorporating three different benzoyl groups 2,2'-(benzoyliminodiethylene)-4-substituted phenols ($L^{1,4,7}$), 2,2'-(4-nitrobenzoyliminodiethylene)-4-substituted phenols ($L^{2,5,8}$) and 2,2'-(3,5-dinitrobenzoyliminodiethylene)-4-substituted phenols ($L^{3,6,9}$) were synthesized and characterized by IR, $^1H$ NMR, $^{13}C$ NMR and mass spectroscopy. The In vitro antibacterial activity of investigated ligands were tested against human pathogenic bacteria such as four Gram (-) Enterococcus faecalis, Pseudomonas aeruginosa, Staphylococcus aureus, Vibrio cholera, Vibrio harveyi and two Gram (+) Staphylococcus aureus, Streptococcus mutans. Furthermore, docking studies were undertaken to gain insight into the possible binding mode of these compounds with the binding site of the topoisomerase II (PDB: 4FM9) enzyme which is involved in DNA superhelicity and chromosome seggregation. The N-benzoylated derivatives $L^{5,7,8}$ have significant anticancer activity as Topoisomerase inhibitors. The ligands $L^5$ and $L^8$ were tested for their anticancer activity against human liver adenocarcinoma (HepG2) cell line with the MTT assay.

• 약학회지
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• 제52권3호
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• pp.219-224
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• 2008

Clinically isolated methicillin-resistant Staphylococcus aureus strains were exposed to subinhibitory concentration of DW286, DW-224a, gemifloxacin, trovafloxacin, sparfloxacin and ciprofloxacin during 26- to 39-days period. Subculturing led to resistance development, and most of the selected mutants were above susceptible breakpoints. Selected mutants had broad cross resistance to other quinolone antibiotics and only one mutant was completely susceptible to all fluoroquinolones. Twenty five among 42 mutants revealed mutations on DNA gyrase and topoisomerase IV by sequencing. Also 16 mutants had fluoroquinolones MICs that were 4-32 times lower in the presence of reserpine. In conclusion, alterations in DNA gyrase or topoisomerase IV and action of efflux pumping out system are the resistance mechanisms of DW-224a.

• Archives of Pharmacal Research
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• 제21권5호
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• pp.581-590
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• 1998

We developed a novel water-soluble camptothecin analobue, CKD602, and evaluated the inhibition of topoisomerase I and the antitumor activities against mammalian tumor cells and human tumor xenografts. CKD602 was a nanomolar inhibitor of the topoisomerase I enzyme in the cleavable complex assay. CKD602 was found to be 3 times and slightly more potent than topotecan and camptothecin as inhibitors of topoisomerase, respecitively. In tumor cell cytotoxicity, CKD602 was more potent than topotecan in 14 out of 26 human cancer cell lines tested, while it was comparable to camptothecin. CKD602 was tested for the in vivo antitumor activity against the human tumor xenograft models. CKD602 was able to imduce regression of established HT-29, WIDR and CX-1 colon tumors, LX-1 lung tumor, MX-1 breast tumor and SKOV-3 ovarian tumor as much as 80, 94, 76, 67, 87% and 88%, respectively, with comparable body weight changes to those of topotecan. Also the therapeutic margin (R/Emax: maximum tolerance dose/$ED-{58}$) of CKD602 was significantly higher than that of topotecan by 4 times. Efficacy was determined at the maximal tolerated dose levels using schedule dependent i.p. administration in mice bearing L1210 leukemia. On a Q4dx4 (every 4 day for 4 doses) schedule, the maximum tolerated dose (MTD) was 25 mg/kg per administration, which caused great weight loss and lethality in <5% tumor bearing mouse. this schedule brought significant increase in life span (ILS), 212%, with 33% of long-term survivals. The ex vivo antitumor activity of CKD602 was compared with that of topotecan and the mean antitumor index (ATI) values recorded for CKD602 were significantly higher than that noted for topotecan. From these results, CKD602 warrants further clinical investigations as a potent inhibitor of topoisomerase I.

• 대한임상검사과학회지
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• 제48권2호
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• pp.74-81
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• 2016

Fluoroquinolone 계 항생제의 광범위한 사용으로 인해 이 약제에 대한 내성 Ureaplasma 종의 분리 비율이 높아지고 있다. Fluoroquinolone 계 항생제 내성은 주로 DNA gyrase와 topoisomerase IV 유전자의 돌연변이로 인해 발생하는 것으로 알려져 있다. DNA gyrase는 A와 B 2개의 소단위로 이루어져 있으며, gyrA와 gyrB 유전자에 의해 암호화되어 있고, Topoisomerase IV는 parC와 parE 유전자에 의해 암호화되어 있다. 본 연구가 진행된 서울의 1개 3차 병원에서 2012년부터 2013년까지 1년동안 Ureaplasma 종의 fluoroquinolone 계 항생제인 OFL과 CIP의 항생제검사 감수성 결과를 분석한 결과 내성과 중등도를 합산할 경우 66.08%, 92.69%로 매우 높은 내성 비율을 보였다. 이에 Ureaplasma 종을 OFL과 CIP에 대한 감수성을 기준으로 4개 그룹으로 분류하여 gyrA, gyrB, parC, parE 유전자의 돌연변이 여부를 검사하여 항생제 내성과의 관련성을 밝히고자 하였다. 그 중 parC 유전자의 돌연변이 빈도가 높아 topoisomerase IV의 돌연변이가 fluoroquinolone 계 약제에 대한 내성과 밀접한 관련이 있음을 확인할 수 있었다. 본 연구를 통해 GyrB의 Asn481Ser, ParC의 Phe149Leu, Asp150Met, Asp151Ile, Ser152Val, ParE의 Pro446Ser, Arg448Lys을 추가로 발견할 수 있었다. 최근 fluoroquinolone 계 항생제의 사용이 증가하고 있기 때문에 추후 Ureaplasma 종의 fluoroquinolone 계 항생제 내성에 대한 지속적인 모니터링이 필수적일 것으로 사료되며, 이와 관련한 유전자의 돌연변이 양상과의 상관관계를 분석하여 기존 배양검사의 단점을 보완할 수 있는 분자 진단학적 검사법의 추가적인 분석이 필요할 것으로 사료된다.

• 대한약학회:학술대회논문집
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• 대한약학회 2004년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2
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• pp.135-137
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• 2004

• 한국동물학회:학술대회논문집
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• 한국동물학회 1995년도 한국생물과학협회 학술발표대회
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• pp.282.2-282
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• 1995

No Abstract, See Full Text