Radiosensitizing and repair-inhibiting properties of dipyridamole.
Radioresistance and postirradiation repair of potentially lethal damage (PLD repair) are important factors underlying failure to control local disease in cancer. Dipyridamole (DP) is known as a modifier of the action of cytotoxic drugs. We therefore investigated DP as a potential radiosensitizer and inhibitor of PLD repair in X-irradiated Chinese hamster ovary (CHO) cells in vitro. Exposure to the drug alone resulted in a slight reduction of the clonogenic capacity of the cells. Preincubation for 18 h with 10 and 20 microM DP in cells subcultured at low density, led to a significant radiosensitization. In confluent density-inhibited cultures, preincubation alone as well as pre- and postincubation with 20 microM DP resulted in a significant inhibition of PLD repair. Dipyridamole and related compounds may thus be useful tools for modifying and investigating the response of mammalian cells to radiation.
Coucke
P A
PA
Department of Radiotherapy, Centre Hospitalier Universitaire Vaudois (CHUV), Lausanne, Switzerland.
Rutz
H P
HP
Calmes
J M
JM
Mirimanoff
R O
RO
D000818:Animals; D002452:Cell Count; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects / Q000528:radiation effects; D006224:Cricetinae; D004249:DNA Damage; D004260:DNA Repair / Q000187:drug effects*; D004176:Dipyridamole / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005260:Female; D010053:Ovary / Q000166:cytology / Q000187:drug effects / Q000528:radiation effects; D011838:Radiation-Sensitizing Agents / Q000494:pharmacology*
D011838:Radiation-Sensitizing Agents; D004176:Dipyridamole