BIOCHEMICAL CONTROL OF BREAST AROMATASE

Aromatase activity is increased in breast tumors and it is possible th at this results from stimulation by cytokines and/or prostaglandin E-2 (PGE(2)) which regulate the activity of this enzyme. As different pro moters can be used to control aromatase gene expression in normal and malignant breast tissues, which are regulated by different factors, we are currently investigating the relative roles of cytokines and PGE(2 ) in controlling breast tumor aromatase activity. No significant effec t of PGE(2) on aromatase activity in MCF-7 breast cancer cells has so far been detected. However, preliminary evidence was obtained, from co -cultures of MCF-7 cells and breast tumor-derived fibroblasts, that MC F-7 cells secrete a factor, possibly a cytokine, which can act in a pa racrine manner to enhance aromatase activity in stromal cells. Underst anding the complex regulation of aromatase activity in breast tumors c ould lead to novel therapies for specifically inhibiting tumor estroge n synthesis.