Growth inhibition of MCF-7 human breast cancer cells by aromatase inhibitors
Fukuoka, M.; Kitawaki, J.; Yamamoto, T.; Okada, H.
Nihon Sanka Fujinka Gakkai Zasshi 43(12): 1667-1673
1991
ISSN/ISBN: 0300-9165 PMID: 1836000 Document Number: 370848
MCF-7 cell line is a model for estrogen-dependent tumors that have both aromatase activity and estrogen receptor. We studied the contribution of aromatase to cell growth and DNA synthesis by means of aromatase inhibitors. MCF-7 cells were cultured in phenol red-free medium containing 10% charcoal-treated fetal bovine serum and test reagents for 96 hours and pulse-labeled with [3H]thymidine for 1 hour. Physiological concentrations of estradiol, estrone, testosterone(T) and androstenedione(delta 4A) increased [3H] thymidine incorporation. Stimulation by T or dihydrotestosterone (DHT) was reduced by tamoxifen, but not by androgen receptor blocker cyproterone acetate, suggesting that T and DHT stimulated cellular proliferation via estrogen receptor but not via androgen receptor. Stimulation by T or delta 4A was reduced by aromatase inhibitors (aminoglutethimide and 14 alpha-hydroxy-4-androstene-3,6,17-trione), but stimulation by nonaromatizable DHT was not reduced by aromatase inhibitors. These results have suggested that estrogens which are biosynthesized from androgens by the intracellular aromatase play a significant role in growth stimulation of MCF-7 cells and that aromatase inhibitors block this pathway. These methods are useful in assessing the ability of aromatase inhibitors to suppress cell growth.