Influence of different growth factors on a rat choriocarcinoma cell line

The influence of epidermal growth factor, insulin-like growth factors I and II, insulin, transforming growth factor beta 1 and transferrin on the growth of a postgestational rat choriocarcinoma was examined by the MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide] assay. The cell line was cultured in RPMI 1640 medium supplemented with fetal calf serum, beta-mercaptoethanol, glucose, sodium pyruvate and antibiotics. The experiments were done in media supplemented with 10% (optimal) or 3% (suboptimal) fetal calf serum. Among the different growth factors tested, only epidermal growth factor and to a certain extent insulin had a growth-promoting effect by themselves. The other growth factors had either an additive effect in the presence of epidermal growth factor or no effect at all. The cytotrophoblast cells expressed both epidermal growth factor and transferrin receptors whereas the more differentiated giant cells expressed only transferrin receptors.