GROWTH OF A HUMAN BREAST-CANCER CELL LINE IN SERUM-FREE HORMONE-SUPPLEMENTED MEDIUM

Abstract

ZR-75-1, a human breast cancer cell line, has been grown in hormone-supplemented medium without serum. The factors required for optimal growth include 17.beta.-estradiol, insulin, transferrin, dexamethasone, and L-triiodothyronine. If estradiol, insulin, or L-triiodothyronine is omitted, cells cease division within 7 days, but viability is retained for at least 14 days. Omission of transferrin leads to cell death within 7 days. The cells have been continuously maintained in this environment without morphological alteration or cessation of growth for more than 5 mo. Addition of the anti-estrogen, Tamoxifen (10-6 M), inhibited cells below the growth rate seen when estradiol was omitted from the medium, even when Tamoxifen was added 4 days and two medium changes after the removal of estradiol from the medium. This suggests an action of Tamoxifen which may be independent of competition with estradiol. The availability of a human breast cancer cell line that can be propagated in hormone-supplemented medium without serum should aid in the study of the mechanisms by which hormones effect cell growth.