Heterogeneous survival and cell kinetics responses of human astrocytoma clones to alpha-difluoromethylornithine in vitro.
The effects of alpha-difluoromethylornithine (DFMO) on survival, cell kinetics and polyamine levels were studied on two clones of human astrocytoma in vitro. The survival responses were dose and time dependent; and treatments with DFMO which lasted for 72 h resulted in heterogeneous responses with one clone being up to 6 times more sensitive than the other. Shorter treatments produced more uniform killing in the clones. A continuous exposure of the cells to 5 mM DFMO resulted in a rapid decrease in putrescine values in both clones, followed by decreases in the spermidine levels. These effects were closely followed by 148% to 170% increases in cell population doubling times, and a lowering of saturation densities. No clear correlations could be established among baseline polyamine levels and cell kinetics or survival responses to DFMO treatments.
Barranco
S C
SC
Department of Radiation Therapy, University of Texas Medical Branch, Galveston 77550.
Ford
P J
PJ
Townsend
C M
CM
D001254:Astrocytoma / Q000378:metabolism / Q000473:pathology*; D015317:Biogenic Polyamines / Q000378:metabolism; D002455:Cell Division / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects*; D002999:Clone Cells / Q000187:drug effects; D000518:Eflornithine / Q000494:pharmacology*; D006801:Humans; D013997:Time Factors; D014407:Tumor Cells, Cultured / Q000187:drug effects / Q000378:metabolism / Q000473:pathology
D015317:Biogenic Polyamines; D000518:Eflornithine