title: Distinct p53-mediated G1/S checkpoint responses in two NIH3T3 subclone cells following treatment with DNA-damaging agents.
abstract: N3T3 and P-3T3 cells, originally isolated from a NIH3T3 cell clone on the basis of their negative and positive transformation by v-Abl, v-Src and Bcr-Abl, were previously found to show distinct cyclin activity changes following 12-O-tetradecanoylphorbol-13-acetate (TPA) treatment, which is anti-mitogenic for N-3T3 cells and mitogenic for P-3T3 cells. We have found in this study that, while the G1/S arrest and cell death induced by serum starvation and TPA treatment in N-3T3 cells did not involve p53-mediated checkpoint or apoptosis, N-3T3 and P-3T3 cells evidently responded differently in these aspects of cell cycle regulation to DNA-damaging agents, methylmethane sulfonate (MMS) and gamma-radiation. In N-3T3 cells, DNA damages elicit cell growth arrest at G1/S transition with concomitant accumulation of p53 and p53-inducible Waf1/Cip1 proteins and also signs of apoptosis such as DNA ladder patterns and apoptotic (subgenomic) peak in flow cytograph. Conversely, P-3T3 cells treated with the DNA-damaging agents showed no cell cycle interruption nor accumulation of p53 or Waf1/Cip1. However, both P-3T3 and N-3T3 cells showed the same p53 protein half-life of 40 min or less, the same wild-type p53 DNA sequence and the same co-immunoprecipitable cellular proteins in complexes with p53, suggesting that an alteration in a signal transduction pathway upstream of p53 might account for the evasion of p53-mediated G1 checkpoint in P-3T3 cells.
authors: Clinical Research Institute, National Health Research Institutes, VGH-Taipei, Taiwan, ROC.
authors: T S
authors: TS
authors: Huang
authors: M L
authors: ML
authors: Kuo
authors: J Y
authors: JY
authors: Shew
authors: Y W
authors: YW
authors: Chou
authors: W K
authors: WK
authors: Yang
mesh_terms: D016475:3T3 Cells / Q000166:cytology / Q000187:drug effects / Q000528:radiation effects; D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology; D001483:Base Sequence; D002455:Cell Division / Q000187:drug effects / Q000502:physiology; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins / Q000096:biosynthesis; D004247:DNA / Q000187:drug effects / Q000528:radiation effects; D004249:DNA Damage; D016193:G1 Phase / Q000187:drug effects / Q000502:physiology* / Q000528:radiation effects; D016158:Genes, p53; D008741:Methyl Methanesulfonate / Q000494:pharmacology; D051379:Mice; D008969:Molecular Sequence Data; D016196:S Phase / Q000187:drug effects / Q000502:physiology* / Q000528:radiation effects; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D016159:Tumor Suppressor Protein p53 / Q000502:physiology*
chemical_list: C493957:Cdkn1a protein, mouse; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D016159:Tumor Suppressor Protein p53; D004247:DNA; D008741:Methyl Methanesulfonate; D013755:Tetradecanoylphorbol Acetate