• Journal of Microbiology and Biotechnology
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• v.10 no.3
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• pp.327-332
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• 2000

Supended cells of Camptotheca acuminata were observed to lose their ability to synthesize camptothecin and its derivatives as a result of repeated cultures. Accordingly, the maintenance of high-yield cells by cryopreservation was sudied to overcome this stability problem, and various factors involved were optimized. Pregrowing the cells in 8% myoinositol for 4 days was found to be the most effective in improving survival. The highest survival was obtained when the pregrown cells were cryoprotected with a mixture of 10% DMSO, 0.6M mannitol, and 10% glycerol. When the cryopreserved cells were maintained in a freezer at $-70^{\circ}C$, 94% survival was obtained after 4 months. The survivals after 5 and 8 months of storage decreased to 52% and 45%, respectively. No loss of biosynthetic capacility of camptothecin was observed after short to medium term cryopreservation of C. acuminata.

• Journal of Microbiology and Biotechnology
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• v.12 no.6
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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.

• Molecules and Cells
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• v.24 no.3
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• pp.416-423
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• 2007

Alterations in the glycan chains of cell surface glycoconjugates are frequently involved biological processes such as cell-cell interaction, cell migration, differentiation and development. Cultured embryonic (E18) rat cortical neurons underwent apoptosis in response to camptothecin, and lectin histochemistry showed that binding to apoptotic neurons of FITC-conjugated Maackia amurensis agglutinin (MAA), which is specific for terminal ${\alpha}2,3$-sialic acid residues, increased progressively with increasing concentrations of camptothecin. Analysis of the total proteins of apoptotic neurons by SDS-PAGE, and lectin blotting using HRP-labeled MAA, revealed that the expression of terminal ${\alpha}2,3$-sialic acid residues on an unknown protein with an apparent molecular mass of 25.6 kDa also increased in apoptotic neurons. NP-HPLC analysis of the total cellular N-glycans of normal and apoptotic neurons demonstrated that the expression of structurally simpler biantennary types of N-glycans fell by 49% during apoptosis whereas the more branched triantennary types of N-glycans with terminal sialic acid residues increased by up to 59%. These results suggest that increased surface expression of ${\alpha}2,3$-sialic acid residues and hyperglycosylation of N-glycans is a common feature of cellular responses to changes in cell physiology such as tumorigenesis and apoptosis.

• YAKHAK HOEJI
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• v.42 no.4
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• pp.431-436
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• 1998

The pharmacokinetics of CKD-602, a new camptothecin anticancer derivative, were studied in mice, rats and dogs following a single or multiple intravenous administration, and the following results were obtained. The blood levels of CKD-602 declined in biphasic fashions with peak plasma levels $(C_0)$ of $2.63{\mu}g/ml$ in mice, $2.27{\mu}g/ml$ in tumor bearing mice, $2.84{\mu}g/ml$ in rats at a dose of 20mg/kg, and of 0.02mcg/ml in dogs at a dose of 0.5mg/kg. The plasma half-lives $(t_{1/2}{\beta})$ were 9.55hr in mice, 9.94hr in tumor bearing mice, 9.98hr in rats and 12.75hr in dogs. AUC of CKD-602 was increased linearly with the dose at a range from 5 to 20mg/kg. Moreover, Cltot and Vdss were also not significantly changed with increasing the dose. On the other hand, after 5 daily intravenous bolus injection of CKD-602 (5mg/kg) in rats, $t_{1/2}{\beta}$, AUC and MRT of CKD-602 were 11.90hr, $3.19{\mu}g{\cdot}hr/ml$, and 11.61hr, respectively, which were slightly higher than after the single bolus injection.

• Journal of agriculture & life science
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• v.45 no.1
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• pp.33-40
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• 2011

An efficient method for the rapid micropropagation of Camptotheca acuminata from axillary buds was established by application of various plant growth regulators. Among various cytokinins, $0.5mg\;L^{-1}$ BA showed the best performance on shoot multiplication, number average multiple shoots up to 10.8. The propagated shoot cuttings in vitro were elongated on NN basal medium without plant growth regulators. The secondary multiple shoots were induced at the site of initially induced buds. Rooting was induced directly near the base of the shoot on half-strength NN medium containing $0.5mg\;L^{-1}$ of IBA, whereas high concentration of $1.0mgL^{-1}$ IBA could induce callus at the base of the shoot. The camptothecin content, anticancer compound of the micropropagated plants was contained in various tissues. Camptothecin contents were 1.8 and $2.5mg\;g^{-1}$ dry weight in stems from propagated in vitro and mother plant, respectively. This result may be used to develop strategies for large-scale propagation of elite C. acuminata trees.

• Journal of Korean Ophthalmic Optics Society
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• v.8 no.1
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• pp.65-71
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• 2003

The corneal epithelium is constantly being shed. The mechanism of corneal desquamation is not fully understood. Apoptosis, programmed cell death, may play a role. Apoptosis can be induced by a number of factors and different mechanisms. The study was performed to examine the apoptotic index induced in human corneal epithelial cells maintained in tissue culture by various apoptotic inducers. Various inducers, recombinant human cytokines($INF{\gamma}$, $TNF{\alpha}$, FASAb), actinomycin D. camptothecin, cycloheximide, dexamethasone and etoposide, were purchased from commercial suppliers. Inducers at manufacturer-recommended concentration were added to the corneal epithelial cells for 48 hours. Cell viability was measured using MTT assay. The cells were then assessed for the level of apoptosis. Morphologic changes and quantification of apoptotic cells were determined and counted under fluorescence microscope after inducers-treated human corneal epithelial (HCE) cells for 48 hours with Hoechst 33342 staining. Annexin V-FITC/PI staining and DePsipher assay. The expression of Fas protein was studied by immunocytochemistry. All inducers induced apoptosis in HCE cells in a dose dependent manner. Actinomycin D. camptothecin and etoposide induced apoptosis at lower than manufacturer-recommended concentration, while cytokines, cycloheximide and dexamethasone induced apoptosis at higher concentrations at the end of 48 hours. All inducers elicited typical apoptotic morphologic changes (chromatin condensation, nucleus fragmentations non-orange-red colored mitochondria) and expresses Fas protein highly. Apoptotic index of HCE cells by these inducers was different from the other cell lines. RNA synthesis inhibitor and topoisomerase inhibitors induced apoptosis at lower concentration than manufacturer-recommended concentration. Cytokines, cycloheximide and dexamethasone were able to produce apoptosis at 10 times higher concentrations. RNA synthesis inhibitor and topoisomerase inhibitors are more sensitive than intracellular receptor-activators in apoptotic induction of HCE cells.

• Archives of Pharmacal Research
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• v.21 no.5
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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.

• YAKHAK HOEJI
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• v.42 no.4
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• pp.437-446
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• 1998

The distribution, metabolism and excretion of CKD-602{20(S)-7-[2-(N-Isopropylamino)ethyl]camptothecin HCI), a new camptothecin derivative, were investigated in rats after a sing le administration of CKD-602. 1. The tissue levels of CKD-602 given to mice by the intravenous route at a dose of 20mg/kg were the highest in intestine, followed in descending order by kidney, liver, stomach,lung, heart, spleen and plasma. The concentrations of CKD-602 after 24hrs decreased to less than 2% of the peak level in most tissues except the skin. The urinary and fecal excretion of CKD-602 were 47.6% and 44.4% of the administered dose, respectively, with 0.7% remaining in the rinse. 2. After administration of CKD-602 at 10mg/kg in rats, metabolism of this compound was examined in plasma, urine, and feces. The plasma samples were collected for 24hr, urinary and fecal samples for 72hr. While any peak of CKD-602 in HPLC chromatograms was not detected from plasma and urine it was detected in feces (peaks, 9.8 min). However, additional peak area was about 0.5% of the peak area of parent CKD-602. Therefore, CKD-602 may be eliminated with the parent form and rarely metabolized in the body. 4. After I.v. administration of CKD-602 at 10mg/kg in rats, urinary and fecal excretions were examined for 72hrs post dose period. 87% of total urinary excretion of CKD-602 was excreted within 8hr after administration, 53%, and 32% of total fecal excreted amounts were determined in 0-24 hr and 24-48hr periods, respectively. The total excretion amounts of CKD-602 into urine and feces were 94% of the administered dose.

• Proceedings of the Korea Environmental Mutagen Society Conference
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• 2004.11a
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• pp.122-122
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• 2004

• Proceedings of the PSK Conference
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• 2001.10a
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• pp.235.1-235.1
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• 2001