Dehydroepiandrosterone sulfate (dhea-s) causes a proliferation of estrogen receptor (er)–positive breast cancer cells, even with tamoxifen citrate blockade. the er antagonist ici 182 780 (fulvestrant) will more effectively stop the proliferative effect of dhea-s on breast cancer cells.
Examination of in vitro breast cancer cell growth in the presence of fulvestrant and dhea-s.
Surgical oncology research laboratory.
The er-positive and er-negative breast cancer cells were pretreated with fulvestrant and stimulated with 900 µg/dl (22.8 µmol/l) of dhea-s.
Main outcome measures
Assays using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, thiazolyl blue, were performed on the third, fifth, and seventh days poststimulation and permitted the calculation of growth percent change.
The er-positive and progesterone receptor–positive cells demonstrated universal proliferation of 107% by day 7 when treated with fulvestrant, regardless of the dose. the er-negative and progesterone receptor–negative cells demonstrated growth inhibition.
The dhea-s circumvented fulvestrant inhibition and caused er-positive breast cancer cell growth.