Soóki-Tóth A, Asghari F, Kirsten E, Kun E
Exp Cell Res. 1987 May;170(1):93-102. doi: 10.1016/0014-4827(87)90119-4.
SV40-3T3 cells were exposed in monolayer cultures to 5 X 10(-7) M methotrexate (MTX), that inhibited thymidylate synthetase, arrested cell growth without cell killing in 24 h and did not induce single- (ss) or double-strand (ds) breaks in DNA. Following 24, up to 72 h, the poly(ADP-ribose) polymerase content of attached cells was induced by 5 X 10(-7) M MTX and the augmentation of the enzyme increased with the time of exposure to the drug. Inhibition of protein or RNA synthesis abolished augmentation of enzymatic activity; so too did the initiation of maximal cell growth by thymidine + hypoxanthine, by-passing the inhibitory site of MTX. Isolation of the ADP-ribosylated enzyme protein by gel electrophoresis identified poly(ADP-ribose) polymerase protein as the molecule that was induced by 5 X 10(-7) M MTX. Under identical conditions, the poly(ADP-ribose) polymerase induction in 3T3 cells could not be demonstrated. A possible cell-cycle-dependent biosynthesis of the enzyme protein is proposed in SV40 3T3 cells.
将SV40 - 3T3细胞以单层培养方式暴露于5×10⁻⁷ M甲氨蝶呤（MTX）中，该药物抑制胸苷酸合成酶，在24小时内使细胞生长停滞但不杀伤细胞，且不会诱导DNA单链（ss）或双链（ds）断裂。在24小时至72小时期间，5×10⁻⁷ M MTX可诱导贴壁细胞的聚（ADP - 核糖）聚合酶含量增加，且随着药物暴露时间延长，该酶的增加量也随之增加。蛋白质或RNA合成的抑制会消除酶活性的增加；通过胸苷 + 次黄嘌呤启动最大细胞生长从而绕过MTX的抑制位点也会如此。通过凝胶电泳分离ADP - 核糖基化酶蛋白，鉴定出聚（ADP - 核糖）聚合酶蛋白是由5×10⁻⁷ M MTX诱导产生的分子。在相同条件下，无法证明3T3细胞中存在聚（ADP - 核糖）聚合酶的诱导现象。在SV40 3T3细胞中提出了该酶蛋白可能存在细胞周期依赖性生物合成的观点。
