• 통합자연과학논문집
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• 제3권3호
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• pp.157-161
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• 2010

New low temperature synthesis of germanium nanoparticles obtained from the reaction of germanium tetrachloride and sodium/benzophenonewere developed. These germanium nanoparticles terminated with chloride group were oxidized in air to give hydroxy-terminated germanium nanoparticles. Germanium nanoparticle containing 20(S)-camptothecin (CPT) for a noble drug delivery system were developed. FT-IR spectroscopy was used for the characterization of vibrational absorption for the germanium nanoparticle and oxidized germanium nanoparticles containing camptothecin. Electronic absorption and fluorescence properties were measured with UV-Vis and fluorescence spectrometer. The morphology of oxidized germanium nanoparticles containing camptothecin was investigated by using TEM.

• Biotechnology and Bioprocess Engineering:BBE
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• 제8권1호
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• pp.32-36
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• 2003

Production of camptothecin ((PT) from callus cultures of Camptotheca acuminata Decne was affected by light and culture conditions. Among the culture media tested, modified B5 medium containing 3% (w/v) sucrose, 2 mg/L B,4-D, 2 times of MS medium vitamins, 500 mg/L casein hydrolysate, 250 mg/L myo-inositol, 0.05% (w/v) activated charcoal, and 0.15% (w/v) gelite was used for callus induction . The highest cell growth and CPT production were obtained in dark and green light condition, respectively. Photoperiod has no effect on cell growth and CPT production. Both cell growth and CPT production were also influenced by combination ratio of red and blue light .Cell growth and CPT production were the highest in the ratio of red and blue light,90:10.

• 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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• 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.

• Animal cells and systems
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• 제15권1호
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• pp.9-17
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• 2011

Colorectal cancer is the third leading cause of cancer-related death in Western countries. Chemotherapeutic agents with different mechanisms of action have shown an increase in cure rates. In the present study, we investigated the effect of a combination of low concentration of paclitaxel (taxol, 5 nM) and topoisomerase 1 inhibitor camptothecin (CPT) on HCT116 colon cancer cells. Although the viability of cells treated with taxol alone was similar to that of control cells, sequential treatment with taxol and CPT exhibited high cytotoxicity. However, the opposite sequence of treatment did not exert cytotoxic effects on HCT116 cells. This enhanced cytotoxicity of the sequential combination therapy was the result of mitotic arrest, which increased the level of $p21^{Cip1/WAF1}$ through the p38 mitogen-activated protein kinase (MAPK) pathway. Knockdown by $p21^{Cip1/WAF1}$ siRNA or treatment with a p38 inhibitor reduced the viability of cells sequentially exposed to taxol and CPT. Taken together, a low taxol concentration in combination with CPT induced mitotic arrest in HCT116 cells, leading to synergistic cell death through enhanced expression of $p21^{Cip1/WAF1}$ and p38 MAPK pathway. Therefore, taxol could playa role as a sensitizer of CPT in colon cancer cells.

• Macromolecular Research
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• 제11권1호
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• pp.47-52
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• 2003

The objective of this study was to develop a polymeric drug delivery system for camptothecin (CPT), capable of improving its therapeutic index and reducing its side effects. A monomeric conjugate, 3,6-endo-methylene-1,2,3,6-tetrahydrophthalimidoethanoylcamptothecin in (ETECPT) between CPT and 3,6-endo-methylene-1,2,3,6-tetrahydrophthalimidoethanoic acid was synthesized. Its homo-and copolymer with acrylic acid (AA) were prepared by photopolymerization using 2,2-dimethoxy-2-phenylacetophenone (DMP) as a photoinitiator. The monomer and its polymers were characterized by IR, $^1$H- and $^{13}$ C-NMR spectra. The ETECPT content in poly(ETECPT-co-AA) obtained by elemental analysis was 82 wt%. The number-average molecular weights of the polymers determined by gel permeation chromatography were as follows: M$_{n}$ = 11,400 for poly(ETECPT), M$_{n}$ = 17,900 for poly(ETECPT-co-AA). The $IC_{50}$/ values of ETECPT and its polymers against cancer cells were much larger than that of CPT. Our results from the in vivo antitumor activity indicated that all polymers show high antitumor activity than CPT at a dose of 100 mg/kg./kg.

• 생명과학회지
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• 제17권6호통권86호
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• pp.748-755
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• 2007

본 연구에서는 전이성 암세포와 항암제 다제내성 세포에 있어서 항암제 내성에 영향을 미치는 것으로 알려진 DNA-dependent protein kinase (DNA-PK) 가 Abl protein-tyrosine kinases저해제인 STl571 내성에도 연관되어 있는지에 대하여 조사하였다. 또한 STl571 과 topoisomerase I 저해제인 camptothecin (CPT) 의 단독 및 병용처리에 의한 항암 활성을 전이성 암세포와 항암제 다제내성 세포를 대상으로 조사하였다. 세포의 전이도와 내성정도에 따라 STl571 의 감수성이 다르게 나타났다. 이와 함께 ST1571의 처리후 농도에 따라 전이도가 낮은 KMl2, PC3 세포와 항암제 감수성인 CEM, MCF-7 세포에서는 DNA-PK 의 발현이 감소하는 반면, 전이도가 높은 KML4a, PC-MM2 세포와 다제내성 CEM/MDR 및 MCR/MDR 세포에서는 그 발현이 증가되어 있음을 알 수 있었다. 이는 DNA-PK 의 발현이 STl571 의 내성에 관여한다는 것을 시사한다. 이와 같은 결과에 근거하여 DNA-PK 의 발현을 감소시키는 CPT를 STl571 내성을 나타내는 암세포에 대하여 STl571 과 병용처리 하였다. 그 결과 DNA-PK의 발현이 감소되고 세포증식이 억제됨으로써 ST1571 의 감수성이 CPT에 의해 증가하는 것을 알 수 있었다. 따라서 본 연구에서는 DNA-PK가 STl571 의 내성을 극복하는데 있어서 새로운 표적이 될 수 있으며, STl571 의 치료내성 극복에 CPT 와의 병용처리가 유효함을 알 수 있었다.

• 대한약학회:학술대회논문집
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• 대한약학회 2001년도 Proceedings of the Pharmaceutical Society of Korea
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• pp.226.2-227
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• 2001

• 대한약학회:학술대회논문집
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• 대한약학회 2000년도 춘계총회 및 학술대회
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• pp.66-69
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• 2000

• 대한약학회:학술대회논문집
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• 대한약학회 2000년도 NEW STRATEGY FOR DRUG DEVELOPMENT IN POST-GENOMIC ERA(대한약학회)
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• pp.262.2-262.2
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• 2000