title: Partial synchronization of L1210 cells by 5-fluorouracil and its use in drug combinations.
abstract: When L1210 cells growing logarithmically were exposed for 8 hr to a nonlethal dose of 5-fluorouracil (FU) (0.25 microgram/ml), the percentage of cells in S phase increased from 74.9% in the asynchronous culture to 93% in the FU-treated culture. This resulted in increased cell-kill by S-phase-specific inhibitors [1-beta-D-arabinofuranosylcytosine (ara-C), 5-hydroxy-2-formylpyridinethiosemicarbazone] when they were added to a culture partially synchronized by pretreatment with FU. For example, 2 hr exposure to ara-C alone or ara-C plus FU (added simultaneously to asynchronous culture) gave 28.8 and 25.8% survival, respectively, compared to 6.8% survival when ara-C was added for 2 hr to the partially synchronized culture. Eight to 12 hr after FU removal, the culture became asynchronous, such that ara-C addition at this time did not result in increased cell-kill. Cultures pretreated with FU were also highly sensitive to vincristine and Adriamycin. Adriamycin acted synergistically with FU (after 8 hr pretreatment) in killing L1210 cells.
mesh_terms: D000818:Animals; D002455:Cell Division / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D003561:Cytarabine / Q000008:administration & dosage / Q000494:pharmacology; D004317:Doxorubicin / Q000008:administration & dosage / Q000494:pharmacology; D004334:Drug Administration Schedule; D004357:Drug Synergism; D004359:Drug Therapy, Combination; D005472:Fluorouracil / Q000008:administration & dosage / Q000494:pharmacology*; D007939:Leukemia L1210 / Q000188:drug therapy* / Q000473:pathology; D013882:Thiosemicarbazones / Q000008:administration & dosage / Q000494:pharmacology; D014750:Vincristine / Q000008:administration & dosage / Q000494:pharmacology
chemical_list: D013882:Thiosemicarbazones; D003561:Cytarabine; D014750:Vincristine; D004317:Doxorubicin; D005472:Fluorouracil