Effect of transforming growth factor beta(2) on oestrogen metabolism in the MCF-7 breast cancer cell line

Transforming growth factor beta (TGF-B) is a multifunctional regulator of c ellular growth and differentiation in many cell types and has a growth inhi bitory effect on mammary epithelial cells. The TGF-beta(2) isoform has been shown to be present in high concentrations in breast cyst fluid and might have a protective role in breast cancer. In addition, oestrogens play an im portant role in breast cancer development, and oestrone sulphate (E1S) migh t be the main source of active oestrogens in the breast. The aim of this st udy was to assess the effect of TGF-beta(2) on oestrogen synthesis in an at tempt to understand the mechanism by which TGF-beta(2) may exert a protecti ve effect in breast cancer. In this study, higher concentrations of TGF-bet a(2) significantly inhibited the conversion of E1S to oestrone (E-1) and th e conversion of E-1 to the potent oestrogen, oestradiol (E-2). TGF-beta(2) did not have any effect on MCF-7 cell growth or on E-2 to E-1 conversion. I n conclusion, TGF-beta(2) might exert a protective role in breast cancer by reducing the amount of active oestrogens present in the breast.