Combined effects of hyperthermia and CPT-11 on DNA strand breaks in mouse mammary carcinoma FM3A cells.
The interaction between hyperthermia and a DNA topoisomerase I inhibitor, 7-ethyl-10-(4-(1-piperidyl)-1-piperidyl)-carbonyloxy- camptothecin (CPT-11), was studied in the mouse mammary carcinoma FM3A cells. When the cells were treated with CPT-11 at a concentration of 5 micrograms/ml and 44 degrees C hyperthermia for 60 min, an enhancement of formation of single stand breaks (ssb) of DNA was observed. However, a decrease of ssb was observed when hyperthermia was combined with CPT-11 at 50 micrograms/ml. For inhibition of DNA synthesis additive effects were observed for treatment with CPT-11 at 5 micrograms/ml combined with hyperthermia. On the other hand, protective effects were observed for the combined treatment at 50 micrograms/ml. These results indicate that the hyperthermic modification of the effect of CPT-11 on the induction of DNA damage was diverse at low or high concentrations.
Kondo
T
T
Department of Radiation Biophysics, Kobe University School of Medicine, Japan.
Ueda
K
K
Kano
E
E
D000818:Animals; D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology*; D002166:Camptothecin / Q000031:analogs & derivatives* / Q000494:pharmacology; D002460:Cell Line; D004249:DNA Damage; D004273:DNA, Neoplasm / Q000096:biosynthesis / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D006358:Hot Temperature; D000077146:Irinotecan; D008325:Mammary Neoplasms, Experimental; D051379:Mice; D059004:Topoisomerase I Inhibitors; D014407:Tumor Cells, Cultured
D000972:Antineoplastic Agents, Phytogenic; D004273:DNA, Neoplasm; D059004:Topoisomerase I Inhibitors; D000077146:Irinotecan; D002166:Camptothecin