Caryometry and nuclear ultrastructure of cultured human breast cancer cells (FAM) after oestradiol administration.
In a breast cancer cell line (FAM) isolated and characterized in our laboratory, we previously observed that oestradiol (E2) did not affect cell multiplication in vitro. In this work, we examined whether these cells bearing oestrogen and progesterone receptors, were oestrogen (E)-sensitive in spite of their lack of growth response. We observed that E2 administration resulted in an increase in protein synthesis characterized by enhancement of progesterone receptors, creatine-phosphokinase and plasminogen activator. Thus these FAm cells were true E-responsive target cells and we studied their nuclear size and ultrastructure to determine if E2 stimulation induced the same important changes as described in vivo. We observed no significant differences between control and E2-treated cells. In these breast cancer cells in vitro, E does not act on DNA-auto-reproduction but only on transcriptional activity. Thus, there is only a limited number of activated genes and no gross nuclear morphological changes. In these cultured oestrogen target cells, ultrastructural nuclear changes are not a marker of hormone action, unlike the situation in vivo where E also acts in triggering cell multiplication.