Cell proliferation kinetics and drug sensitivity of exponential and stationary populations of cultured L1210 cells

Drug sensitivity and cell cycle parameters of L1210 cells in culture in exponential (10(5) to 4 x 10(5) cells/ml) and plateau phase (greater than 8 x 10(5) cells/ml) of growth were compared. The percentage of cells in G1, S, and G2 + M for exponential and plateau-phase cultures was 24.1, 70.0, and 5.9, and 42.5, 45.6, and 11.9, respectively. These values correspond to those reported previously for early and late L1210 mouse leukemia cells. Cell survival (measured by cloning) after drug exposure showed that actinomycin D, 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea, chlorozotocin, and streptozocin were all equally lethal to cells in both phases, and 1-beta-D-arabinofuranosylcytosine, high-specific-activity (20Ci/mmole) [3H]thymidine, vincristine, daunomycin, adriamycin, and 5-fluorouracil were more lethal to exponential cells than to plateau-phase cells. The percentage kill by S-phase-specific agents such as 1-beta-D-arabinofuranosylcytosine and[3H]thymidine corresponded well with the percentage of cells in S. Finally, 1,3-bis(2-chloroethyl)-1-nitrosourea was more toxic to plateau cells than to exponential cells.