INDUCTION OF HUMAN ADENOCARCINOMA CELL-DIFFERENTIATION BY THE PHYTOESTROGEN GENISTEIN IS INDEPENDENT OF ITS ANTIESTROGENIC FUNCTION

The objective of the present study was to determine if genistein can i nduce human breast adenocarcinoma cell maturation. To gain understandi ng on its mechanism of action, we used estrogen receptor-positive (ER( +)) MCF-7, and ER MDA-MB-468 cells. Treating these cells with genistei n resulted in growth inhibition accompanied by increased cell maturati on, which was evaluated by the production of casein and lipids. These maturation markers were optimally expressed after nine days of treatme nt with 30 mu M of genistein. Since both ER(+) and ER(-) cells became differentiated, we conclude that the ER is not a component of the geni stein-initiated scheme of cellular differentiation.