Antitumor activity of CKD-602, a camptothecin derivative, in a mouse glioma model

CKD-602 (7-[2-(N-isopropylamino)ethyl]-(20S)-camptothecin, belotecan), a novel synthetic water-soluble camptothecin derivative, is known to have a significant anticancer effect in vitro on human glioma cell lines, including U87MG and U251MG. In the present study, we evaluated the in vivo antitumor effect of CKD-602 in a mouse glioma model. Nude mice with established U87MG glioma were treated with a dose of CKD-602 of 0 mg/kg (control group, injection with saline only; n = 5), 40 mg/kg (group A) or 60 mg/kg (group B). Thereafter, the dose was repeated once every 4 days for a total of four doses. Tumor volume was measured histologically and apoptosis was detected using the terminal deoxynucleotide transferase dUTP nick end labeling (TUNEL) assay and immunofluorescence analysis with cleaved caspase-3. Mean tumor volume in each group was: control, 145.35 mm3; group A, 76.51 mm3; group B, 73.99 mm3). Tumor volume was significantly smaller in both groups A and B compared with the control group (group A, p < 0.01; group B, p < 0.05). Apoptosis of tumor cells was evident to a greater extent in groups A and B relative to the control group, but there were no significant differences in tumor volume or apoptotic index between groups A and B. These results suggest that CKD-602 has a significant anticancer effect on glioma cells in vivo.