Tamoxifen and ZK 119010 exert mixed agonistic and antagonistic effects on pS2 expression in MCF-7 cells.
pS2 is a major estradiol-inducible gene in MCF-7 breast cancer cells. In this study we tested the effects of tamoxifen and ZK 119010, a novel nonsteroidal antiestrogen, on pS2 gene expression with or without a pretreatment of cells with estradiol (10(-11), 10(-8) M). Estradiol increased pS2 expression in MCF-7 cells approximately 12-fold. Tamoxifen (10(-6) M) reduced estradiol-induced pS2 expression to 78% of the stimulated level, while ZK 119010 was 50% effective. Given alone, either of the two antiestrogens in the above concentrations evoked a pS2 gene expression in MCF-7 cells significantly above background levels. From these data we conclude that the antiestrogens tamoxifen and ZK 119010 possess both antagonistic and agonistic potencies in MCF-7 cells. However, the antiestrogenic potency of ZK 119010 seems to be higher than that of tamoxifen.
Schütze
N
N
Institut für Biochemische Endokrinologie, Medizinische Universität, Lübeck, Germany.
Schneider
M R
MR
Knuppen
R
R
Vollmer
G
G
D015152:Blotting, Northern; D001943:Breast Neoplasms / Q000235:genetics*; D004965:Estrogen Antagonists / Q000494:pharmacology*; D004967:Estrogens / Q000819:agonists*; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects*; D006801:Humans; D007211:Indoles / Q000494:pharmacology*; D009363:Neoplasm Proteins / Q000235:genetics*; D013629:Tamoxifen / Q000494:pharmacology*; D014407:Tumor Cells, Cultured
D004965:Estrogen Antagonists; D004967:Estrogens; D007211:Indoles; D009363:Neoplasm Proteins; D013629:Tamoxifen; C071554:ZK 119010