title: Nitrosourea-induced sister chromatid exchanges and correlation to cell survival in 9L rat brain tumor cells.
abstract: The ability of various nitrosoureas to induce sister chromatid exchanges (SCEs) in 9L rat brain tumor cells was investigated. Treatment of cells for 1 hr with the alkylating and cross-linking agents 1,3-bis(2-chloroethyl)-1-nitrosourea or chlorozotocin produced concentration-dependent increases in SCEs; elevations above controls were detected at concentrations of 1 microM or more. Above 0.25 mM, the alkylating agent ethylnitrosourea produced a dose-dependent increase in SCEs. Treatment with the carbamoylating agent 1,3-bis(trans-4-hydroxycyclohexyl)-1-nitrosourea did not induce SCEs. The maximum drug concentration at which SCEs are readily scored kills approximately 50% of cells. When accurate cell survival data in this dose range were obtained, a direct correlation between nitrosourea-induced cell kill, measured by a colony-forming efficiency assay, and SCE induction was found. Thus, analysis of the levels of SCE production may provide information about the efficacy of antineoplastic drugs.
mesh_terms: D000818:Animals; D001932:Brain Neoplasms / Q000503:physiopathology*; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D003434:Crossing Over, Genetic / Q000187:drug effects*; D007700:Kinetics; D009374:Neoplasms, Experimental / Q000503:physiopathology; D009607:Nitrosourea Compounds / Q000494:pharmacology*; D051381:Rats; D012854:Sister Chromatid Exchange / Q000187:drug effects*; D013329:Structure-Activity Relationship
chemical_list: D009607:Nitrosourea Compounds