Continuous culture and soft agarose cloning of multiple human breast carcinoma cell lines in serum-free medium

We tested the ability of a serum-free medium containing insulin, transferrin, 17 beta-estradiol, dexamethasone, triiodothyronine, prostaglandin F2 alpha, and fibronectin (HBCA medium) to support the continuous growth and passage of five human breast carcinoma cell lines on a collagen matrix. Doubling times of the cell lines (20 to 44 hr) were similar in HBCA and serum-supplemented media. The gross morphology of the cell lines was not altered in the serum-free medium. Insulin, transferrin, and the collagen matrix were the most essential factors required for optimal growth of the cell lines. Estradiol appeared to stimulate the growth of cell lines, both with and without estrogen receptors. HBCA medium supplemented with low concentrations of bovine serum albumin, Fraction V (0.5%, v/v), supported the clonal growth of three cell lines in soft agarose with colony-forming efficiencies superior to that observed with standard serum-supplemented medium. Deleting estradiol from HBCA medium reduced the colony-forming efficiency of the three cell lines. HBCA medium may be useful in studying hormonal regulation and improving the in vitro growth of human breast cancer.