Schnitzler R, Foth J, Degen G H, Metzler M
Department of Chemistry, University of Kaiserslautern, Germany.
Mutat Res. 1994 Nov 1;311(1):84-93. doi: 10.1016/0027-5107(94)90076-0.
The induction of micronuclei (MN) is a known effect of the carcinogenic estrogen diethylstilbestrol (DES). We have now tested the time course and dose dependence of MN induction by DES and its analogs 3',3"-DES, indenestrol A (IA), indenestrol B (IB) or by the steroidal estrogen 17 beta-estradiol (E2) and by the clastogenic compound 4-nitroquinoline-N-oxide (NQO) in two primary mammalian cell culture systems. All compounds induced MN in Syrian hamster embryo and ovine seminal vesicle cells with compound-specific time courses and dose dependences. DES induced a maximum MN frequency 12 h post treatment, whereas with all other estrogens the highest MN frequency was observed 3-6 h after removal of the compound. The maximum MN frequency after NQO treatment occurred at 24 h or later. Of the stilbene estrogens tested, only DES caused an increase of the mitotic index. Further characterization of the MN by indirect immunofluorescence microscopy using CREST antikinetochore antibodies revealed that 92-99% of the DES-induced MN but only 0-2% of the NQO-induced MN contained CREST-reactive kinetochores. Since kinetochore-positive MN are indicative of whole chromosomes/chromatids and kinetochore-negative MN of acentric chromosomal fragments, our findings support the view that DES acts as a pure aneuploidogen and NQO as a pure clastogen in the two cell systems. In the case of 3',3"-DES, IA, IB and E2, 41-68% of the induced MN contained CREST-reactive kinetochores. As the time courses of MN induction are not compatible with those of clastogenic agents, it is proposed that these estrogens induce MN containing chromatids/chromosomes with altered kinetochore structures.
微核（MN）的诱导是致癌雌激素己烯雌酚（DES）的一种已知效应。我们现在已经在两种原代哺乳动物细胞培养系统中测试了DES及其类似物3',3"-DES、茚雌酚A（IA）、茚雌酚B（IB）、甾体雌激素17β-雌二醇（E2）以及致断裂化合物4-硝基喹啉-N-氧化物（NQO）诱导MN的时间进程和剂量依赖性。所有化合物均在叙利亚仓鼠胚胎细胞和绵羊精囊细胞中诱导出MN，且具有化合物特异性的时间进程和剂量依赖性。DES在处理后12小时诱导出最大MN频率，而对于所有其他雌激素，在去除化合物后3 - 6小时观察到最高MN频率。NQO处理后的最大MN频率出现在24小时或更晚。在所测试的二苯乙烯类雌激素中，只有DES导致有丝分裂指数增加。使用着丝粒抗动粒抗体通过间接免疫荧光显微镜对MN进行进一步表征显示，92 - 99%的DES诱导的MN含有CREST反应性动粒，但只有0 - 2%的NQO诱导的MN含有CREST反应性动粒。由于动粒阳性的MN表明是整条染色体/染色单体，而动粒阴性的MN表明是无着丝粒染色体片段，我们的研究结果支持这样一种观点，即DES在这两种细胞系统中作为一种纯粹的非整倍体诱变剂起作用，而NQO作为一种纯粹的断裂剂起作用。对于3',3"-DES、IA、IB和E2，41 - 68%的诱导MN含有CREST反应性动粒。由于MN诱导的时间进程与断裂剂的时间进程不相符，因此有人提出这些雌激素诱导含有动粒结构改变的染色单体/染色体的MN。
