Effects of 5-aza-2'-deoxycytidine on survival and cell cycle progression of L1210 leukemia cells.
The in-vitro effects of the antileukemic agent 5-aza-2'-deoxycytidine (5-aza-dCyd), on DNA synthesis, growth, cloning in agar, and cell cycle traverse of L1210 leukemia cells were studied. 5-Aza-dCyd at 0.1 microgram/ml for 10 hr (cytotoxic concentration) did not inhibit DNA synthesis but produced a very potent growth inhibition, and changed markedly the DNA flow cytometric histograms. A 5-h continuous exposure to the drug at concentrations ranging from 0.1 to 10 micrograms/ml caused an accumulation of cells in the S portion of the DNA histograms indicating a slowing of the progression of cells in the S phase. A longer exposure time (10 h) at the same concentrations led to a bimodal DNA distribution (peaks at G1 and G2-M) and a depletion of the S phase. When the exposure time to 5-aza-dCyd (0.1 microgram/ml) was extended to 15 and 20 h, there was a decrease in the G2-M peak and an augmentation of the G1 peak. To determine if 5-aza-dCyd produced a block in cell cycle progression, L1210 cells were treated for 10 h with colcemid and 5-aza-dCyd simultaneously for 10 h. Colcemid alone, or colcemid in combination with 5-aza-dCyd produced an accumulation of cells under a single G2-M peak. This indicates that 5-aza-dCyd did not block the progression of L1210 cells through S phase, but only produced a slowing down of this event. These results, indicating that 5-aza-dCyd does not block cell cycle progression and that its cytotoxic action is not self-limiting, are of importance for designing future clinical trials.
G G
GG
Chabot
R L
RL
Momparler
D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D001374:Azacitidine / Q000031:analogs & derivatives* / Q000494:pharmacology; D002453:Cell Cycle / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D004273:DNA, Neoplasm / Q000032:analysis; D000077209:Decitabine; D007939:Leukemia L1210 / Q000188:drug therapy / Q000473:pathology*; D051379:Mice; D013936:Thymidine / Q000378:metabolism
D000970:Antineoplastic Agents; D004273:DNA, Neoplasm; D000077209:Decitabine; D001374:Azacitidine; D013936:Thymidine