Evaluation of chromosome aberrations induced by digoxin in Chinese hamster ovary cells

Abstract

Digoxin is a cardiac glycoside that has been reported to inhibit growth of multiple tumor cell types in vitro. The present study was assessing the cytogenetic effects of this drug on Chinese Hamster Ovary (CHO) cells. All experiments were performed in triplicate. The IC50 was 22.5 ± 0.8 µg/ml. To investigate the clastogenic effects of drug, chromosomal aberration in metaphase cells were analyzed. Chromatid breaks and polyploidy were the main types of aberration. Mitomycin-C and sodium arsenite were used as positive controls. CHO cells were exposed to different concentration of drug (5, 10, 15, 20 µg/ml) in 24 hours. All of the study aberrations and frequency of aberrant cells significantly increased as a function of digoxin concentration (for chromatid breaks: r = 0.881, df = 13, P < 0.001; for polyploidy: r = 0.777, df = 13, P = 0.001; for cells with aberrations: r = 0.926, df = 13, P < 0.001). The mitotic index negatively correlated with the concentration of digoxin (r = -0.978, df = 13, P < 0.001). All concentrations that cause chromosomal aberrations are in the cytotoxic range of the drug. The peak serum digoxin concentration (5 - 20 ng/ml) was very lower than concentrations we used in the present experiments. Further studies on valuation of chromatid breaks, micronuclei, and sister chromatid exchange in lymphocytes of patients who received digoxin, were recommended.

Keywords: chromatid breakage; digoxin; mitotic index; polyploidy.

Table 1. Induction of chromatid breaks, polyploidy and mitotic index in CHO cells by digoxin

Figure 1. Effect of digoxin concentration on CHO cell line for 24 hours: The results are presented as percent of inhibition of cell growth obtained by MTT assay. Data are mean ± SD of triplicate cultures.