title: Regulation of DNA repair kinetics in proliferative and quiescent tumor cells.
abstract: The radiosensitivity and kinetics of repair of radiation-induced DNA damage were determined for proliferative (P) and quiescent (Q) cells of the mouse mammary adenocarcinoma line 67. 67 Q cells are more radiosensitive than 67 P cells. Radiation induced the same amount of DNA damage in both 67 P and 67 Q cells. Both 67 P and 67 Q cells repaired their DNA damage with biphasic kinetics, but the half-times for the fast and slow phase were longer in 67 Q cells. Q cell DNA appeared to be in a more compact or condensed chromatin structure and was less accessible to enzymatic digestion than P cell DNA. These data suggest that 67 Q cells are more sensitive to ionizing radiation than 67 P cells because they repair their radiation-induced DNA damage more slowly, perhaps as a result of their more condensed chromatin structure.
mesh_terms: D000230:Adenocarcinoma / Q000235:genetics* / Q000473:pathology / Q000662:veterinary; D000818:Animals; D002460:Cell Line; D004247:DNA / Q000528:radiation effects; D004249:DNA Damage; D004260:DNA Repair; D066298:In Vitro Techniques; D007700:Kinetics; D008321:Mammary Glands, Animal; D051379:Mice
chemical_list: D004247:DNA