Sister chromatid exchange frequency, cellular replication and relative cloning efficiency in human teratocarcinoma-derived cells.

To determine the relationships between the induction of specific biological responses and exposure to DNA-damaging agents, human teratocarcinoma-derived cells were exposed to either ethyl methanesulfonate or to methyl methanesulfonate, and sister chromatid exchange, cellular proliferation and relative cloning ability measured. SCE increased while cellular proliferation and relative cloning ability each decreased in a concentration-dependent manner. Methyl methanesulfonate was consistently more efficient in inducing biological responses than was ethyl methanesulfonate. When the individual responses were compared, the decrease in cellular proliferation paralleled the reduction in cloning efficiency. A strong correlation was also observed between the reduction in relative cloning ability and sister chromatid exchange frequency. Because these relationships are similar to those previously described in other mammalian cell lines, the observations in our study suggest that the P3 cell line is an appropriate choice for modeling effects of toxicant exposure in human cells.