• Journal of Microbiology and Biotechnology
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• 제8권1호
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• pp.89-91
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• 1998

Cryptotanshinone induced topoisomerase I-mediated DNA cleavage in vitro as strongly as camptothecin, whereas topoisomerase II-mediated DNA cleavage was not induced by this agent. In DNA relaxation assay using calf thymus DNA topoisomerase I and supercoiled pBR322 DNA, cryptotanshinone inhibited topoisomerase I-mediated DNA relaxation in a dose-dependent manner. In unwinding assay, cryptotanshinone ($50{\mu}M$) did not shift the topoisomers of DNA. These results suggest that cryptotanshinone exerted a preferential inhibition of topoisomerase I without intercalating into DNA.

• BMB Reports
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• 제34권1호
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• pp.85-89
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• 2001

Both topoisomerase $II{\alpha}$ and $II{\beta}$ east as phosphoproteins in the cells. Recently it was reported that DNA topoisomerase $II{\alpha}$ associates with and is phosphorylated by the extracellular signal-regulated kinase 2 (ERK2). Also, ERK2 stimulates the activity of topoisomerase II by a phosphorylation-independent manner [Shapiro et al., (1999) Mol. Cell. Biol. 19, 3551-3560]. In this study, a yeast two-hybrid system was used to investigate the binding site between topoisomerase $II{\alpha}$ or $II{\beta}$ and ERK2. The two-hybrid test clearly showed that topoisomerase $II{\beta}$ residues 1099-1263, and topoisomerase $II{\alpha}$ residues 1078-1182, mediate the interaction with ERK2, and that the leucine zipper motifs of topoisomerase $II{\alpha}$ and $II{\beta}$ are not required for its physical binding to ERK2. Our results suggest that topoisomerase $II{\beta}$ residues 1099-1263, and topoisomerase $II{\alpha}$ residues 1078-1182, may be common binding sites for activator proteins.

• 약학회지
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• 제40권6호
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• pp.697-704
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• 1996

Quinolone derivatives, SJ5b (ethyl 5,12-dihydro-5-dihydro-5-oxobenzoxazolo[3,2-a]quinoline-6-carboxylate) and SQ7b (3-fluoro-2-(4-methylpiperazin-1-yl)-5.12-dihydro-5-oxobenzoxa zolo[3,2-a]quinoloine carboxylic acid) showed in vitro cytotoxicities against various tumor cell lines. SJ5b and SQ7b completely inhibited the DNA relaxation activities of human placental topoisomerase II at the concentration of 15.63 and 1.95 ${\mu}$g/ml, respectively. However, unlike etoposide which stabilize the topoisomerase II-DNA complex, SQ7b did not cause topoisomerase II-mediated DNA cleavage and SJ5b weakly stabilized the topoisomerase II-DNA cleavable complex. Through both experiments. DNA relaxation assay by the increment of topoisomerase II concentration and DNA unwinding assay, it was shown that SJ5b and SQ7b did not interact with topoisomerase II itself but bound to DNA. Therefore, it was concluded that DNA binding of SJ5b and SQ7b caused the inhibition of topoisomerase II related to DNA relaxation but no or very weak stabilization of topoisomerase II-DNA cleavable complex. In addition, SJ5b and SQ7b prevented whole cell nucleic acid syntheses in HL60 cells.

• 생명과학회지
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• 제18권1호
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• pp.75-83
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• 2008

인체 DNA topoisomerase는 DNA를 단일 또는 두 가닥을 일시적인 절단을 촉매하여 DNA의 topological 문제를 조절함으로써, DNA 복제, 전사, 재조합과 유사분열 과정 등에 관여한다. 이 효소는 많은 항생, 항암제의 표적효소로서 널리 알려져 있으며, 이들 유도체를 이용한 다양한 억제제의 개발과 임상적 응용에 관한 연구가 활발하게 진행되고 있다. 본 실험에서는 인체 백혈병 HL-60 세포에서 topoisomerase 억제제가 topoisomerase 기능 활성과 유전자 발현을 조절하는지를 규명하기 위하여 본 연구를 수행하였다. 연구 방법은 HL-60세포에 topoisomerase type I과 type II의 대표적 억제제인 10-hydroxycamptothecin (10-CPT)과 doxorubicin을 투여한 후 total RNA를 분리하였고, 10K-oligo-nucleotide microarray 방법으로 분석하여 유전자의 발현 양상을 조사하였다. 연구 결과에 의하면 10-CPT 또는 doxorubicin을 투여한 HL-60세포에서의 유전자 발현 양상은 주로 signal transduction, cell adhesion, cell cycle, cell growth, cell proliferation, cell differentiation, transcription 및 immune response 등과 관련이 있었다. Topoisomerase type I의 억제제인 10-CPT를 HL-60 세포주에 투여 하였을 때 type I으로 분류되는 topoisomerase III${\alpha}$, III${\beta}$ 및 I의 발현은 증가하였으나 type II인 topoisomerase II${\alpha}$와 II${\beta}$의 유전자의 발현은 감소되었다. 반대로 type II의 억제제인 doxorubicin을 투여하였을 때는 앞의 결과와 상반된 topoisomerase II${\alpha}$와 II${\beta}$의 유전자의 발현이 현저히 증가되었으며, topoisomerase III${\alpha}$와 III${\beta}$의 mRNA의 발현은 약간 감소하는 양상을 보였으나 의미 있는 차이는 없었다. 이 연구 결과는 앞으로 항암제의 기전을 밝히고 약물에 대한 치료 반응을 예측하고 새로운 약제 개발에 기초자료가 될 것으로 여겨진다.

• Biomolecules & Therapeutics
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• 제29권5호
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• pp.562-570
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• 2021

Topoisomerase IIα has been a representative anti-cancer target for decades thanks to its functional necessity in highly proliferative cancer cells. As type of topoisomerase IIα targeting drugs, topoisomerase II poisons are frequently in clinical usage. However, topoisomerase II poisons result in crucial consequences resulted from mechanistically induced DNA toxicity. For this reason, it is needed to develop catalytic inhibitors of topoisomerase IIα through the alternative mechanism of enzymatic regulation. As a catalytic inhibitor of topoisomerase IIα, AK-I-191 was previously reported for its enzyme inhibitory activity. In this study, we clarified the mechanism of AK-I-191 and conducted various types of spectroscopic and biological evaluations for deeper understanding of its mechanism of action. Conclusively, AK-I-191 represented potent topoisomerase IIα inhibitory activity through binding to minor groove of DNA double helix and showed synergistic effects with tamoxifen in antiproliferative activity.

• 약학회지
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• 제47권3호
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• pp.125-129
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• 2003

A series of 2-phenyl-5-nitrobenzimidazoles substituted at the para positon of the 2-phenyl moiety was synthesized ＆ evaluated for their activity to inhibit topoisomerase I. The structure-activity relationship study revealed that neither the electronic nor lipophilic parameters were related to the topoisomerase I inhibition. A strict spatial requirement seems to be present for retention of topoisomerase I inhibition activity.

• 한국식품과학회지
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• 제29권5호
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• pp.1057-1062
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• 1997

26속 32종의 버섯의 topoisomerase II 작용 억제여부를 검색한 결과 말불버섯이 topoisomerase II 작용을 억제하며 그 유효 성분이 핵산분획물에 존재함을 확인하였다. 말불버섯의 핵산분획물은 linear DNA와 open circular DNA를 생성시켰으며 농도와 반응시간에 의존적인 반응 양상을 나타냈다. 또한 말불버섯의 핵산분획물은 topoisomerase I의 작용도 억제하였다. 그러나 배양한 말불버섯의 균사체는 topoisomerase 작용에 아무런 영향을 미치지 않았다.

• Journal of Microbiology and Biotechnology
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• 제12권6호
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• pp.1013-1016
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• 2002

Cyclo(L-prolyl-L-phenylalanyl) [cyclo(pro-phe)] was isolated from Streptomyces sp. AMLK-335 and found to inhibit DNA topoisomerase I activity. In a DNA relaxation assay using supercoiled pBR322 DNA, cyclo(pro-phe) inhibited the DNA topoisomerase activity more strongly than camptothecin, a known topoisomerase inhibitor. However, at a concentration of $10{\mu}M$, cyclo(pro-phe) produced a lower degree of DNA relaxation than camptothecin, therefore, the inhibition of topoisomerase I activity by cyclo(pro-phe) was also found to be dose dependent. Accordingly, the current results suggest that cyclo(pro-phe) may be a novel inhibitor of topoisomerase I.

• Journal of Microbiology and Biotechnology
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• 제6권5호
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• pp.366-367
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• 1996

Dibutyl phthalate induced topoisomerase Ⅰ mediated DNA relaxation comparable to that of camptothecin, and topoisomerase Ⅱ mediated DNA relaxation equipotent to that of 4'-(9-acridinylamino) methanesulfon-m-anisidide (m-AMSA). The relaxation activities of dibutyl phthalate were dose-de-pendent and nearly as potent as those of camptothecin and m-AMSA.

• 약학회지
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• 제55권6호
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• pp.441-445
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• 2011

A series of 8-(substituted)aryloxy- and 8-alkyloxy-caffenines were prepared from 8-bromocaffeine and (substituted) phenols as well as alkanols by Ullmann reaction and their inhibitory activities on topoisomerase II were evaluated. A compound, 8-(quinolin-2-yl)oxycaffeine showed the strongest inhibitory activity against topoisomerase II.