THE REGULATION OF GROWTH AND PROTEIN EXPRESSION BY ESTROGEN IN-VITRO - A STUDY OF 8 HUMAN OVARIAN-CARCINOMA CELL-LINES

The effects of 17 beta-estradiol (E(2)) on the growth and the levels of estrogen receptor (ER), progesterone receptor (PR) and pS2 protein were examined in a range of 8 ovarian carcinoma cell lines. E(2) stimulated growth of the 3 cell lines with an ER content of 80-220 fmol/mg protein but not the 5 cell lines with ER concentrations less than 20 fmol/mg protein, After exposure to E(2), ER concentration in 2 of the 3 responsive cell lines was decreased relative to untreated cells and in 2 lines, progesterone receptors were increased. No change in steroid receptor levels-was observed in cell lines with low or negligible levels of receptors. The pS2 protein was not induced by E(2) in the 5 ovarian carcinoma cell lines examined. These results indicate that E(2) can stimulate the growth of some ER-positive ovarian carcinoma cells and that these effects may be associated with changes in the cellular levels of steroid hormone receptors.