title: Enhanced cell killing through the use of cell kinetics-directed treatment schedules for two-drug combinations in vitro.
abstract: Kinetics-directed drug treatment schedules were tested in Chinese hamster ovary cells. Ten hr after treatment with 1,2:5,6-dianhydrogalactitol (DAG) (at a dose lethal to less than 5% of the cells), a 150% enrichment of cells into the S phase of the cell cycle was observed. This blockade in S phase was reversible and was followed at 18 hr after an exposure to DAG by a 200% increase in the fraction of cells in the G2-M phases of the cell cycle. Bleomycin, known to be most effective against G2 + M cells, had the greatest effect on cell killing when administered at that time. Rapid analysis by flow microfluorometry techniques was used to determine the DAG-induced kinetics changes, thus allowing treatment with the second drugs at the most opportune time. The DAG-induced kinetics changes were also demonstrated in a line of human adenocarcinoma of the stomach in vitro and in Ehrlich ascites tumor cells in vivo. In all cases, the enrichment of cells into S phase was reversible at the doses used and was followed by a reversible blockade in G2-M.
mesh_terms: D000230:Adenocarcinoma / Q000503:physiopathology; D000818:Animals; D001761:Bleomycin / Q000008:administration & dosage*; D002286:Carcinoma, Ehrlich Tumor / Q000503:physiopathology; D002453:Cell Cycle / Q000187:drug effects*; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects*; D002478:Cells, Cultured; D006224:Cricetinae; D003412:Cricetulus; D003961:Dianhydrogalactitol / Q000008:administration & dosage*; D004334:Drug Administration Schedule; D004359:Drug Therapy, Combination; D005260:Female; D006801:Humans; D007700:Kinetics; D051379:Mice; D010053:Ovary / Q000166:cytology; D013402:Sugar Alcohols / Q000008:administration & dosage*
chemical_list: D013402:Sugar Alcohols; D001761:Bleomycin; D003961:Dianhydrogalactitol