Effect of transforming growth factor β₂ on oestrogen metabolism in the MCF-7 breast cancer cell line

Abstract

Transforming growth factor β (TGF-β) is a multifunctional regulator of cellular growth and differentiation in many cell types and has a growth inhibitory effect on mammary epithelial cells. The TGF-β₂ 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 important role in breast cancer development, and oestrone sulphate (E₁S) might be the main source of active oestrogens in the breast. The aim of this study was to assess the effect of TGF-β₂ on oestrogen synthesis in an attempt to understand the mechanism by which TGF-β₂ may exert a protective effect in breast cancer. In this study, higher concentrations of TGF-β₂ significantly inhibited the conversion of E₁S to oestrone (E₁) and the conversion of E₁ to the potent oestrogen, oestradiol (E₂). TGF-β₂ did not have any effect on MCF-7 cell growth or on E₂ to E₁ conversion. In conclusion, TGF-β₂ might exert a protective role in breast cancer by reducing the amount of active oestrogens present in the breast.