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 ant i-oestrogens on the growth of human ovarian cancer cells. Tamoxifen an d the ''pure'' anti-oestrogens, ICI 164,384 and ICI 182,780, inhibited the oestrogen-stimulated growth of the oestrogen receptor (ER)-positi ve PE04 and PE01 cell lines grown in culture, the latter two compounds being more potent than tamoxifen. In the absence of 17 beta-oestradio l (E(2)), tamoxifen, but not the pure anti-oestrogens, produced a smal l degree of growth stimulation in the PE01 and PE04 lines at concentra tions between 10(-7) and 10(-9) M. In contrast, growth of the ER-negat ive PE014 line was unaffected by E(2) and all three anti-oestrogens. T he effects of tamoxifen and ICI 182,780 on PE04 cells grown as xenogra fts in nude mice were also studied. Both anti-oestrogens produce signi ficant growth inhibitory effects. These results indicate that ovarian carcinoma cells may be sensitive to anti-oestrogens in vitro and in vi vo, and support the view that antioestrogens merit further clinical st udies in patients with ER-positive tumours.