• Bulletin of the Korean Chemical Society
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• 제26권11호
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• pp.1829-1832
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• 2005

• 한국식품영양과학회지
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• 제29권5호
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• pp.917-921
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• 2000

This study was carried out to investigate the effects on the mutagenicity and activity of DNA topoisomerase I of Sarcodon aspratus. Using an Ames mutagenicity test, which has been used to assess both mutagenic and antimutagenic effects of various molecules, it was observed that the methanol extracted fraction and other fractions (prepared in water or ethylacetate) of Sarcodon aspratus showed a significant antimutagenic activity against a mutagenecity induced by both a direct mutagenic agent such as MNNG and an indirect mutagenic agents such as B(a)P and AFB$_1$in Salmonella typhimurium TA98, TA100. Also, the extract and fractions of Sarcodon aspratus were found to have an inhibitory activity on the relaxation process of DNA topoisomerase I.

• 약학회지
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• 제49권5호
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• pp.428-436
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• 2005

DNA topoisomerase I(TOP1) helps the control of DNA replication, transcription and recombination by assist­ing breaking and rejoining of DNA double strand. Camptothecin (CPT) and its derivative, topotecan, are known to inhibit TOP1 by intercalating into TOP1-DNA complex. Recently various non-CPT intercalators are synthesized for a new class of TOP1 inhibitors. In this study, six compounds isolated from Poria cocos were investigated for their interaction with TOP1­DNA complex using the flexible docking program, FlexiDock. The binding modes were analyzed and compared with the TOP1 inhibition activities. The compounds that showed potent activity were intercalated between the + 1/-1 base pairs of DNA, located near the active site phosphotyrosine723 and formed hydrogen bonds with active site residues. On the other hand, compounds with no activity were not docked at all. The binding modes were well correlated with the inhibition activity, suggesting the possibility that potent inhibitors can be designed from the information presented by the docking study.

• 생약학회지
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• 제30권1호
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• pp.1-6
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• 1999

To evaluate cytotoxic effect and topoisomerase I inhibition activity of Caesalpinia sappan L., both water and methanol extracts were examined using in vitro assay. The cytotoxic effect of Caesalpinia sappan L. examined using MTT and SRB assay and $IC_{50}$ values were measured against U937, HL60, HepG2, SNU-1, SNU-16 cancer cell lines. Among them the representative cytotoxic results are shown as follows; water extract (U937=13.39 ${\mu}g/ml$, HL60=8.65 ${\mu}g/ml$, HepG2=38.48 ${\mu}g/ml$, SNU-1=7.72 ${\mu}g/ml$, SNU-16=25.49 ${\mu}g/ml$), methanol extract (U937=13.35 ${\mu}g/ml$, HL60=9.43 ${\mu}g/ml$, HepG2=25.67 ${\mu}g/ml$, SNU-1=8.37 ${\mu}g/ml$, SNU-16=28.64 ${\mu}g/ml$). The inhibitory concentration of DNA topoisomerase I activity against water extract was 100 ${\mu}g/ml$ and the inhibitory concentration of DNA topoisomerase I against methanol extract was 400 ${\mu}g/ml$.

• 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.

• Bulletin of the Korean Chemical Society
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• 제34권10호
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• pp.3073-3082
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• 2013

Designed and synthesized twenty-four 2,4-diaryl benzofuro[3,2-b]pyridine derivatives were evaluated for topoisomerase I and II inhibitory activities as well as cytotoxicities against several human cancer cell lines. Various aryl groups such as phenyl, 2- or 3- furyl, 2- or 3-thienyl, and 2-pyridyl were substituted at 2- or 4- position of central pyridine. Compounds 8, 12, 13, and 14, with 2-furyl either at 2- or 4- position of central pyridine showed the significant topoisomerase II inhibitory activity at 100 ${\mu}M$.

• Journal of Microbiology and Biotechnology
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• 제29권4호
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• pp.571-576
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• 2019

Microenvironmental stress, which is naturally observed in solid tumors, has been implicated in anticancer drug resistance. This tumor-specific stress causes the degradation of topoisomerase $II{\alpha}$, rendering cells resistant to topoisomerase $II{\alpha}$-targeted anticancer agents. In addition, microenvironmental stress can induce the overexpression of 78kDa glucose regulated protein (GRP78), which can subsequently block the activation of apoptosis induced by treatment with anticancer agents. Therefore, inhibition of topoisomerase $II{\alpha}$ degradation and reduction in GRP78 expression may be effective strategies for inhibiting anticancer drug resistance. In this study, we investigated the active compound arctigenin, which inhibited microenvironmental stress-induced etoposide resistance in HT-29 cells. Arctigenin was also highly toxic to etoposide-resistant HT-29 cells, with an $IC_{50}$ value of $10{\mu}M$ for colony formation. We further showed that arctigenin inhibited the degradation of topoisomerase $II{\alpha}$ and reduced the expression of GRP78. Thus, these results suggest that arctigenin is a novel therapeutic agent that inhibits resistance to etoposide associated with microenvironmental stress conditions.

• Archives of Pharmacal Research
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• 제27권8호
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• pp.829-833
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• 2004

The bioactivity-guided fractionation of the methylene chloride extract of the sclerotium of Poria cocos led to the isolation of (S)-(＋)-turmerone (1), ergosterol peroxide (2), polyporenic acid C (3), dehydropachymic acid (4), pachymic acid (5), and tumulosic acid (6). Compounds 4-6 exhibited moderate cytotoxicities, with $IC_{50}$ values of 20.5, 29.1, and $10.4{\;}\mu\textrm{m}$, respectively, against a human colon carcinoma cell line. However, 3-6 not only showed inhibitory activities as potent as etoposide used as a positive control on DNA topoisomerase II (36.1, 36.2, 43.9 and 66.7％ inhibition at a concentration of $20{\;}\mu\textrm{m}$, respectively), but also inhibition of DNA topoisomerase I (55.8, 60.7, 43.5, and 83.3％ inhibition at a concentration of $100{\;}\mu\textrm{m}$, respec-tively).

• Archives of Pharmacal Research
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• 제21권6호
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• pp.729-733
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• 1998

The crude extract of Streptomyces sp. strain KM86-9B, isolated from a marine sponge, displayed significant inhibition on topoisomerase I activity. Investigation of the ca usative components by bioactivity-directed fractionation resulted in the isolation of a series of iso- and anteiso-fatty acids.

• BMB Reports
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• 제31권3호
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• pp.245-248
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• 1998

Human epidermoid carcinoma A431 cells have an extraordinarily large number of epidermal growth factor (EGF) receptors, and their growth is inhibited by EGF, which results in growth arrest at the Gl phase. In order to investigate the EGF-mediated inhibition mechanism, the expression level of DNA topoisomerase (topo) II was analyzed after EGF treatment. As a result, it was shown that EGF treatment lowered the amount of 170 kDa topo II (topo $II{\alpha}$) but not 180 kDa (topo $II{\beta}$). However, the A431 cell variant resistant to EGF was not sensitive to EGF treatment. These results suggest that EGF-induced growth arrest of A431 cells may be closely related to the depletion of topo $II{\alpha}$.