Camptothecin (CPT)

348, 35

Nude mice (NIH-I high fertility strain) bearing xenografts of CASE, SW48, DOY, SPA, and CLO cells

Investigations of Camptothecin and its analogues in multiple Phase I–III clinical trials for various cancers have been completed.

0–8 mg/kg

0.68 uM [2], 0.68 uM [2], 0.68 uM [2], 0.68 uM [2], 0.68 uM [2], 0.68 uM [2]

Camptothecin (8 mg/kg) displays complete growth inhibition and regression in mice xenografts of various tumors, including colon, lung, breast, stomach, and ovary tumors. [3] In mice, combinations of Camptothecin (50 mg/kg) and TNF (5 and 7 ug/kg), but not Camptothecin alone, induces liver damage. [4]

[2], Topoisomerase I Cleavable Complex Assay, Topoisomerase I is isolated from calf thymus and is devoid of topoisomerase II. All reactions are carried out in 10 mL volumes of reaction buffer (50 mM Tris-HCl, pH 7.5, 100 mM KCl, 0.5 mM EDTA, and 30 pg/mL BSA) in microtiter plates. Camptothecin is dissolved in DMSO at 10 mg/mL and serially diluted in 96-well microtiter plates to which the 32P end-labeled pBR322 DNA and topoisomerase enzyme are added. The reaction mixture is incubated at room temperature for 30 min and then the reaction stopped by adding 2 mL of a mixture of sodium dodecyl sulfate and proteinase K (1.6% and 0.14 mg/mL final concentrations, respectively). The plates are heated at 50 C for 30 min, 10 mL of standard stop mixture containing 0.45 N NaOH is added in order to generate single-stranded DNA, and the samples are electrophoresed in 1.5% agarose gels in TBE buffer. Gels are blotted on nitrocellulose paper, dried, and exposed to X-ray film. The units of cleavage are calculated from the autoradiographs and plotted against the log drug concentration. The IC50 values are then obtained.

DMSO 3 mg/mL, Water <1 mg/mL, Ethanol <1 mg/mL