Inhibition of transforming growth factor-beta and matrix metalloproteinases by estrogen and prolactin in breast cancer cells

Hormones, estrogen and prolactin, transforming growth factor-beta (TGF-β), and matrixmetalloproteinases (MMPs) may modulate breast cancer progression. The goal of this research was to examine the regulation of expression of TGF-β and MMPs (MMP-1, 2, 9) by estrogen and prolactin, independently and in combination, at physiological doses, and at doses stimulating cancer cell (T47D) proliferation in vitro. Prolactin, and estrogen synergistically, and similarly, inhibited the expression of TGF-β and MMPs at physiological concentrations without altering cell proliferation, indicating a beneficial role of the hormones. The growth stimulating concentration of prolactin, but not estrogen, also inhibited the TGF-β and MMP expression.