Noscapine hydrochloride-induced numerical aberrations in cultured human lymphocytes: a comparison of FISH detection methods and multiple end-points

The cytokinesis block in vitro micronucleus (MN) assay in combination with CREST staining and fluorescence in situ hybridization (FISH) with chromosome-specific DNA probes allows mechanistic information on the induction of numerical chromosomal aberrations to be obtained through a rapid and simple microscopic analysis. These techniques can now be used to investigate relationships between the induction of chromosomal loss, non-disjunction and polyploidy by aneuploidy-inducing agents. In the present study, we treated 72 h cultured lymphocytes for the last 24 h of culture with various concentrations of the cough medicine noscapine hydrochloride (NOS) (3.9-120 mug/ml) in the presence of either cytochalasin B (CYB) (3 mug/ml) or 5-bromo-2'-deoxyuridine (BrdU) (1 muM). Using the CREST staining modified MN assay in the CYB-treated cultures, we detected significant increases in CREST-positive but not CREST-negative MN in both binucleated and, to a lesser extent, mononucleated cells, demonstrating the ability of this compound to induce chromosomal loss. In addition, using FISH with chromosome 1- and 9-specific classical satellite probes, a significant induction of chromosomal non-disjunction in the binucleated lymphocytes and polyploidy in the mononucleated lymphocytes was seen, indicating that polyploidy induced by NOS may occur without progression through a normal anaphase and/or telophase. In the BrdU-treated cultures, a dose-dependent induction of hypodiploidy, hyperdiploidy and polyploidy was observed using FISH with a chromosome 9-specific alpha-satellite probe in the labeled cells. By comparison, in the unlabeled non-cycling cells, only a slight increase in hyperdiploidy/polyploidy but not hypodiploidy was seen. A comparison of the effects seen at different concentrations shows that at the lower effective concentrations, all three types of numerical aberrations, chromosomal loss, non-disjunction and polyploidy, contributed to the numerical aberrations seen, whereas at the highest concentration tested, polyploidy was the predominant alteration. These studies indicate that FISH in combination with CYB or BrdU immunfluorescent staining can be sensitive tools for the identification of aneuploidy-inducing agents.