Colcemid-induced neoplastic transformation and aneuploidy in Syrian hamster embryo cells.

Treatment of Syrian hamster embryo cells in culture with 0.01-0.1 micrograms/ml of colcemid for 48 h resulted in morphological and neoplastic transformation of the cells. Cell transformation was observed with doses which were non-cytotoxic and did not cause mitotic inhibition of the cells. Higher dose of colcemid (greater than 0.1 microgram/ml) resulted in mitotic inhibition of the cells and a significant loss of colony forming ability, but no increase in the frequency of morphological transformation. Treatment of the cells with transforming doses of colcemid did not result in any measurable induction of gene mutations or structural chromosome aberrations; however, numerical chromosome changes in the treated cells were observed. A 14-fold increase in the number of aneuploid cells with a near diploid chromosome complement was found in cultures treated with 0.1 micrograms/ml colcemid and both chromosome loss and gain were induced. The dose response curves for colcemid induced morphological transformation and aneuploidy were similar. These results are consistent with a role of carcinogen-induced chromosome non-disjunction in carcinogenesis.