Colcemid-induced polyploidy and aneuploidy in normal and tumour cells in vitro

The frequency of colcemid-induced genome mutations (aneuploidy and polyploidy) in normal and SV40-transformed cultures of Djungarian hamster embryonic cells was studied. Genome mutations were easily induced by the drug in transformed but not in normal cultures. Elevation of colcemid concentration and prolongation of the incubation period did not substantially increase the frequency of genome mutations in normal cells. An attempt was made to study the causes of the differences in sensitivity to colcemid-mutagenicity of normal and transformed cells. Transformed cells did not include more 3H-colchicine than normal cells, and binding of the drug to cell homogenates was similar in both kinds of cultures. According to these data the higher sensitivity of transformed cells to colcemid is not connected either with increased permeability of the cell to the drug or with changes in its binding to tubulin.