Dose-response studies of the induction of hyperdiploidy and polyploidy by diethylstilbestrol and 17β-estradiol in cultured human lymphocytes using multicolor fluorescence in situ hybridization

Diethylstilbestrol (DES) and 17β-estradiol (E₂) are known inducers of aneuploidy and polyploidy in vivo and in vitro. Isolated human lymphocytes were treated with the stilbene estrogen DES (0.05–50 μM) and the steroid estrogen E₂ (0.05–75 μM) in culture. Multicolor fluorescence in situ hybridization (FISH) with DNA probes for the centromere and adjacent heterochromatin regions of chromosomes 1, 9, and 16 was used to detect hyperdiploidy, polyploidy, and chromosomal breakage affecting these chromosomes. Using this FISH technique, significant nonlinear increases in hyperdiploidy were observed with both compounds, whereas no induction of chromosomal breakage affecting the pericentric heterochromatin regions of chromosomes 1, 9, and 16 could be detected. DES induced a maximum of approximately 13% hyperdiploid cells at 30 μM, whereas E₂ showed its highest induction at 75 μM with 7% hyperdiploid cells. To distinguish hyperdiploidy from polyploidy, a FISH labeling strategy to detect multiple chromosomes simultaneously was established. Using this approach, we could show that most of the cells showing multiple hybridization regions after treatment with both chemicals were most likely the result of polyploidy rather than true hyperdiploidy. These results indicate that the induction of hyperdiploidy/polyploidy with DES and E₂ show sublinear dose-response relationships with likely threshold concentrations in human lymphocytes and that FISH with multiple probes targeting different chromosomes can be used to estimate hyperdiploidy and polyploidy frequencies. Environ. Mol. Mutagen. 31:263–273, 1998 © 1998 Wiley-Liss, Inc.