Estrogen control of progesterone receptor in human breast cancer. Correlation with nuclear processing of estrogen receptor.

摘要: MCF-7 cells of human breast cancer origin responded to estradiol (E) treatment with increased levels progesterone receptor (PgR) showing that which have undergone malignant changes can continue synthesize a specific protein under hormone control. These results were obtained by studying the effects addition and withdrawal E on PgR synthesis correlating this estrogen (ER) binding translocation nuclear processing reactions restoration unoccupied ER. In treated 1-5 days (.001-100 nM) basal (.3-.7 pmol/mg deoxyribonucleic acid) 3-6 fold. response was dose-dependent .1 nM (a physiologic dose) maximal effective dose. Growth induction suppressed an antiestrogen Tamoxifen at 10000-fold molar excess (1 mcgM) but reversed supraphysiological (10 reduced only 100-fold. cell line ER not restricted cytoplasm (Rc) since portion cellular also be found in nucleus form (RN). The level correlated extent Rc Rn binding. At 85% depleted maximally stimulated. paralleled bound (RnE) appearing nucleus. Processing during new steady-state RnE achieved appeared saturable event. low doses despite failed accumulate total decreased. loss approached 70% E. But higher some remained unprocessed increased. effect rapid beginning within 10 minutes completed 5 hours. Processed seen before maintenance induced states. withdrawn fell parallel end Rn.