Effects of pinostrobin on estrogen metabolism and estrogen receptor transactivation

The interaction between the estrogen receptor and 5-hydroxy-7-methoxyflavanone (pinostrobin) was studied in the presence or absence of estradiol or dehydroepiandrosterone sulfate (DHEAS), respectively, using a stably transfected human breast cancer cell line (MVLN). We also evaluated its action on the proliferation in estrogen-dependent (MCF-7) human breast cancer cells in the same conditions than the estrogen receptor assay. On the other hand pinostrobin was evaluated for their effects on the human placental aromatase, 3 beta -hydroxysteroid dehydrogenase Delta (4)/Delta (5) isomerase and 17 beta -hydroxysteroid dehydrogenase activities. Pinostrobin did not possess antiestrogenic activity but presented anti-aromatase activity and decreased the growth of MCF-7 cells induced by DHEAS and E-2. This study provides particularly evidence of the potential biological interest of pinostrobin among the flavonoids. (C) 2000 Elsevier Science Ireland Ltd. Ail rights reserved.