Characterisation of aromatase expression in the human adipocyte cell line SGBS.

Aromatase is a member of the cytochrome P450 superfamily of enzymes which catalyses the rate-limiting step in the biosynthesis of estrogens. A number of clinical studies have highlighted the importance of local estrogen production in adipose tissue. In particular, in the postmenopausal woman, the degree of her estrogenization is mainly determined by the extent of her adiposity and it is this extragonadal source of estrogen that likely contributes to breast cancer development and progression. The mechanisms regulating aromatase expression in adipose tissue however, have not been fully elucidated. In this study, we have characterised the expression of aromatase and its activity in a human preadipocyte cell strain, SGBS. Aromatase is expressed in SGBS cells and its expression and activity are strongly stimulated by forskolin (FSK) and phorbol 12-myristate-13-acetate (PMA) treatment. Consistent with this, FSK and PMA treatment also increased activation of the proximal aromatase promoter, promoter II. These findings mimic those that have previously been shown in isolated primary human preadipocytes. These data suggest that SGBS cells are a valuable model with which to further elucidate the mechanisms regulating aromatase expression, and therefore local estrogen synthesis in human adipose tissue.