Proliferation of a human embryonal carcinoma-derived cell line in serum-free medium: inter-relationship between growth factor requirements and membrane receptor expression.

Substantial multiplication in vitro of cloned cells from a human embryonal carcinoma cell line, Tera 2, has been obtained in a basal medium (DMEM/Ham's F12,50:50, v/v) supplemented with 10 micrograms low density lipoprotein/ml, 100 micrograms high density lipoprotein/ml, 100 ng multiplication stimulating activity/ml, 100 ng insulin/ml and 1 microgram transferrin/ml. The growth rate appears to be similar to that obtained in 10% serum. Furthermore, studies on the expression of cell surface receptors revealed that cloned Tera 2 cells express high-affinity receptors for IGF-II but not for insulin. The cells also express receptors for Epidermal Growth Factor (EGF) even though the addition of EGF does not stimulate their proliferation in serum-free medium. These results suggest that the expression of specific growth factor receptors is not an absolute determinant of hormone responsiveness.