OBJECTIVEIt was reported previously that genistein could inhibit proliferation of human ovarian carcinoma cell line SKOV(3), but mechanism was not clear. There is a close relationship between EGFR mediated signal transduction pathway and the development of ovarian tumor. This study aimed to investigate the effects of genistein on the EGFR mediated signal transduction pathway and to clarify its mechanisms of proliferation inhibition on human ovarian carcinoma cell line SKOV(3) and its xenograft in nude mice.

METHODSThe expression of c-erbB-2 protein was determined using immunocytochemistry. The expressions of c-jun and c-fos protein were determined using Western blotting. The expression of c-erbB-2, c-raf-1, c-jun and c-fos mRNA were tested by reverse transcription-polymerase chain reaction (RT-PCR).

RESULTSThe expression of c-erbB-2, c-raf-1 and its downstream gene c-jun and c-fos were decreased at mRNA level in the 20 micromol/L genistein group. The expression of c-erbB-2 protein were decreased, its average absorbency (A) were decreased after treatment of SKOV(3) with 20 micromol/L genistein for 48 h, reached at 0.42 +/- 0.02 (P < 0.05). Western blotting demonstrated that the expressions of c-jun and c-fos protein were decreased gradually after being treated with 20 micromol/L genistein for 12 - 72 h.

CONCLUSIONSGenistein could down-regulate the expression of two key genes, c-erbB-2 and c-raf-1 at mRNA and protein level in the EGFR mediated signal transduction pathway, and down-regulate the expression of its downstream nuclear transcription factors c-jun and c-fos at mRNA and protein level. It is suggested that interfering the expressions of some key signal molecules in EGFR mediated signal transduction system by genistein may account for its molecular foundation of proliferation inhibition in ovarian carcinoma.