Cytogenetic effects of Me-CCNU on sister chromatid exchange frequency, cellular kinetics and chromosome aberrations

1-(2-Chloroethyl)-3-(trans-4-methylcyclohexyl)-1-nitrosourea (Me-CCNU) was tested for its in vitro effects on sister chromatid exchanges (SCE), cellular kinetics and chromosome aberrations in CHO cells. There was a relationship between the inhibitory activity of the drug and the cytogenetic damage, which was dose dependent. Increase in SCE values were highly significant (p less than 0.001) for all the four concentrations used. It also delayed the cell cycle progression. Inhibition of DNA synthesis results in increased frequency of chromosomal aberrations, which was highly significant for the higher concentrations, i.e. 5 micrograms and 10 micrograms Me-CCNU/ml.