• Biomolecules & Therapeutics
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• v.29 no.5
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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.

• YAKHAK HOEJI
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• v.53 no.4
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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.

• Archives of Pharmacal Research
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• v.27 no.1
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• pp.77-82
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• 2004

DA-125, a novel derivative of adriamycin, is known for its anti-cancer activity. In this study, the inhibitory mechanism of DA-125 on topoisomerase was investigated in the simian virus 40 (SV40) replicating CV-1 cell by studying the SV40 DNA replication intermediates and DNA-topoisomerase complexes. DNA-protein complexes that were formed in the drug-treated cells were quantitated by using a glass filter assay. SV40 DNA replication intermediates that were accumulated in the drug-treated CV-1 cell were analyzed in a high resolution gel. DA-125 did not accumulate B-dimers of SV40 DNA replication intermediates which were found in the adriamycin-treated CV-1 cells. DA-125 induced a dose-dependent formation of the DNA-protein complexes, while adriamycin did not. When adriamycin and etoposide (VP16) were added to the SV40-infected cells at the same time, adriamycin blocked the formation of the DNA-protein complexes induced by VP16 in a dose-dependent manner. However, DA-125 blocked the formation of the DNA-protein complexes induced by VP16 up to the maximum level of the DNA-protein complexes that were induced by DA-125 alone. Adriamycin and DA-125 did not inhibit the formation of the DNA-protein complexes that were caused by camptothecin, a known topoisomerase I poison. DA-125 is bifunctional in inhibiting topoisomerase II because it simultaneously has the properties of the topoisomerase II poison and the DNA intercalator. As a topoisomerase II poison, DA-125 alone induced dose-dependent formation of the DNA-protein complexes. However, as a DNA intercalator, it quantitatively inhibited the formation of the DNA-protein complexes induced by a strong topoisomerase II poison VP16. Furthermore considering that the levels of the DNA-protein complex induced by VP16 were decreased by DA-125 in terms of the topoisomerase II poison, we suggest that DA-125 has a higher affinity to the drug-binding sites of DNA than VP16 has.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.36 no.3
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• pp.177-185
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• 2010

Introduction: Epidermal growth factor receptor (EGFR) is expressed in human epithelial tumors including salivary cancers, and known to be correlated with tumor progression and poor clinical courses in some epithelial tumors. In this study, we determined the therapeutic effect of the anti-EGFR monoclonal antibody Erbitux (C225, cetuximab) in combination with the DNA topoisomerase I inhibitor irinotecan (CPT-11) on human salivary adenoid cystic carcinoma (SACC) cells growing in nude mice. Materials and Methods: At first, immunocytochemical analysis for the expression of EGFR and phosphorylated EGFR (pEGFR) on a human salivary ACC cell line (ACC3). To determine the in vivo effects of Erbitux and CPT-11, nude mice with orthotopic parotid tumors were randomized to receive intraperitoneal Erbitux (1 mg) two times per week, intraperitoneal Irinotecan (50 mg/kg) once per week, Erbitux plus CPT-11, or placebo. (control) Tumor volume and weight were measured. And mechanisms of in vivo activity of Erbitux and/or CPT-11 were determined by immunohistochemical/ immunofluorescent analyses. Results: Immunocytochemical staining of ACC3 demonstrated that EGFR was expressed and phosphorylated. CPT-11 inhibited ACC tumor growth in nude mice. Tumors of mice treated with CPT-11 and CPT-11 plus Erbitux exhibited increased tumor cell apoptosis and decreased microvessel density, which correlated with a decrease in the tumor volume in nude mice. But, CPT-11 seems not to be synergistic with Erbitux in our ACC3 model system. Conclusion: These results suggest that anti-EGFR monoclonal antibody and the DNA topoisomerase I inhibitor will be effective in the treatment of recurred or metastatic lesions of salivary ACC.

• The Journal of Korean Medicine
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• v.22 no.2
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• pp.22-30
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• 2001

This study was attempted to investigate the anti-tumor and anti-metastatic effects of Sobokchukeotang(SBCT) and Kamisobokchukeotang(KSBCT). Cytotoxicity against various cancer cell lines, anti-adhesion, pulmonary colonization, anti-angiogenesis, and T/C% were evaluated. SBCT and KSBCT exhibited no cytotoxicity against HT-1080, A549, SK-OV-3, B16-F10 and SK-Mel-2 cell lines. In inhibitory effect on DNA topoisomerase I, the $IC_{50S}$ were shown $250-500{\;}\mu\textrm{g}/ml$ of SBCT and $62.5-125{\;}\mu\textrm{g}/ml$ of KSBCT respectively. In the in vivo experiments, SBCT(135.98%) and KSBCT(151.92%) apparently increased the life span of mice bearing sarcoma-180. KSBCT significantly inhibited the adhesion of HT-1080 to complex extracellular matrix in a dose-dependent manner in contrast to SBCT. In pulmonary colonization assay by B16-F10, a number of colonies in the lungs were decreased more significantly in KSBCT group than those in SBCT group. In vitro neovascularization and CAM assay, angiogenesis was more significantly inhibited in KSBCT-treated group than in SBCT- treated group. Above results suggests that KSBCT is more effectively applied to prevention and treatment of cancer than SBCT.

• Bulletin of the Korean Chemical Society
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• v.25 no.4
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• pp.539-544
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• 2004

The ability of protoberberine alkaloids, berberine and berberrubine, to act as topoisomerase II poisons is linked to the anti-cancer activity. Minor alterations in structure have a significant effect on their relative activity. Berberine, which has methoxy group at the 19-position, is significantly less potent than berberrubine. Several observations support non-specific binding to HP14 by the berberine: (i) nonspecific upfield changes in $^1H$ chemical shift for protons of the berberine; (ii) the broadening of imino protons of HP14 upon binding of the berberine; (iii) very small increases in duplex melting temperature in the presence of the berberine. Our results reveal that substitution of a hydroxyl group to a methoxy group on the 19-position, thereby converting the berberrubine to the berberine is associated with a non-specific DNA binding affinity and a reduced topoisomerase II poisoning. The presence of a bulky 19-methoxy substituent decreases intercalating properties of berberine and makes it inactive as topoisomerase II poison.

• Journal of Physiology & Pathology in Korean Medicine
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• v.16 no.3
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• pp.472-478
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• 2002

The purpose of this study was to investigate the effect of Kamigedang-tang(KGDT) water extract on the antitumor and anti metastatic activity. The results were summarized as follows: KGDT extracts exhibited a significant cytotoxicity against P388, SK-MEL-2, SK-OV-3, and B16-F10 cell lines and showed significant inhibitoty effect on DNA topoisomerase I from calf thymus. The T/C% was 122.9% in KGDT treated group in S-180 bearing ICR mice. Also, KGDT extracts exhibited efficient affect adhesive effect of A549 cell to complex extracellular matrix. In CAM assay, KGDT extracts inhibited angiogenesis at 15㎍/egg concentration insignificantly as compared with control. These results suggested that KGDT extracts might be usefully applied for prevention and treatement of cancer.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.11
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• pp.4853-4856
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• 2016

Objective: Gimatecan is a new camptothecin (CPT) analogue that inhibits tumor growth by targeting DNA topoisomerase I (TOP I) and introducing strong and persistent DNA cleavage. Anti-tumor activity has been demonstrated with a wide range of solid tumors in previous preclinical and clinical studies. Here, we investigated for the first time the effects of gimatecan on the proliferation of hepatocellular carcinoma (HCC) cells both in vitro and in vivo. Methods: Anticancer efficacy of gimatecan were evaluated in a panel of HCC cell lines and corresponding mouse xenograft models. Inhibition of cell proliferation was measured by CellTiter-Glo cell viability assay. In vivo, gimatecan and control preparations were orally administered every four days, for a total of four times. Tumor volume and body weights of the mice were measured twice weekly. Results: In vitro cytotoxicity evaluation showed that gimatecan inhibited the proliferation of a large panel of HCC cell lines in a dose dependent manner, with IC50 values ranging between 12.1~1085.0 nM. In vivo evaluation in mouse xenograft models showed significant antitumor effects of gimatecan at 0.8mg/kg and 0.4mg/kg as compared to the control group. Conclusion: This study suggested that gimatecan may have the potential to be used as a chemotherapeutic agent for the treatment of HCC.

• Journal of Physiology & Pathology in Korean Medicine
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• v.16 no.4
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• pp.667-673
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• 2002

The purpose of this study was to investigate the effect of Kamisamchulsamja-tang (KSST) water extract on the antitumor activity. The results were summarized as follows: KSST extract exhibited a weak cytotoxicity against HT1080, A549, SK-OV-3, B16-F10 and SK-MEL-2 cells. KSST extract showed a inhibitoty effect on DNA topoisomerase I from calf thymus in a dose-dependent manner. Also, KSST extract showed antiadhesive effect on HT1080 cells but didn't showed on A549 cells to complex extracellular matrix. In pumonary colonization assay, a number of colonies in the lungs were decreased significantly in KSST treated group as compared with control group. In vitro neovascularization assays, angiogenesis was significantly inhibited in KSST treated group than control group. In CAM assay, KSST extract inhibited angiogenesis significantly at 15㎍/egg concentration as compared with control. From the above results it was concluded that KSST showed antitumor effect through the antimetastatic effect. So it is expected to be clinically helpful on the prevention of metastasis of cancer.

• Journal of Physiology & Pathology in Korean Medicine
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• v.17 no.3
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• pp.765-770
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• 2003

To explore the possible cancer agent from oriental prescriptions, we have examined its antitumor and anti metastatic activities of Kamibojungikgi-tang(KBIT). KBIT extracts exhibited cytotoxicity against P388, A549 and B16-F10 cell lines in a dose-dependent manner and showed antiadhesive effect of A549 cell to complex extracellular matrix at 1 ㎎/㎖ in vitro. In DNA topoisomerase I assay, KBIT extracts showed strong inhibitoty effect in a dose-dependent manner. In pulmonary colonization assay with B16BL6, a number of colonies in the lungs were decreased effectively in KBIT treated group as compared with control group. Moreover, in CAM assay, KBIT extracts significantly inhibited angiogenesis at 15㎍/egg as compared with control. The T/C% was 141% in KBIT treated group in S-180 bearing ICR mice. From the above results it was concluded that KBIT had antitumor and anti metastatic activities. So it is expected to be clinically helpful on the prevention and treatment of cancer, although it is still necessary to study its mechanism on molecular biology and immunology.