GROWTH-INHIBITION OF ESTROGEN RECEPTOR-POSITIVE HUMAN OVARIAN-CARCINOMA BY ANTIESTROGENS IN-VITRO AND IN A XENOGRAFT MODEL

This paper presents results of the in vitro and in vivo effects of anti-oestrogens on the growth of human ovarian cancer cells. Tamoxifen and the ''pure'' anti-oestrogens, ICI 164,384 and ICI 182,780, inhibited the oestrogen-stimulated growth of the oestrogen receptor (ER)-positive PE04 and PE01 cell lines grown in culture, the latter two compounds being more potent than tamoxifen. In the absence of 17 beta-oestradiol (E(2)), tamoxifen, but not the pure anti-oestrogens, produced a small degree of growth stimulation in the PE01 and PE04 lines at concentrations between 10(-7) and 10(-9) M. In contrast, growth of the ER-negative PE014 line was unaffected by E(2) and all three anti-oestrogens. The effects of tamoxifen and ICI 182,780 on PE04 cells grown as xenografts in nude mice were also studied. Both anti-oestrogens produce significant growth inhibitory effects. These results indicate that ovarian carcinoma cells may be sensitive to anti-oestrogens in vitro and in vivo, and support the view that antioestrogens merit further clinical studies in patients with ER-positive tumours.