Regulation of breast tumor growth by high dose estrogen is independent of the presence of estrogen receptors.
17 beta-estradiol stimulated the clonogenic growth of four established human breast tumor cell lines independent of the estrogen receptor status of the cells. Likewise, tamoxifen citrate, a nonsteroidal antiestrogen, inhibited the in vitro growth of both estrogen receptor-negative and estrogen receptor-positive cell lines to a similar degree. These findings indicate that, at pharmacologic doses, the growth stimulatory and inhibitory effects of estrogen and antiestrogens are not necessarily mediated by hormone-specific receptors.
D001943:Breast Neoplasms / Q000032:analysis / Q000378:metabolism / Q000503:physiopathology*; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D004958:Estradiol / Q000008:administration & dosage / Q000494:pharmacology*; D006801:Humans; D010996:Pleural Effusion; D011960:Receptors, Estrogen / Q000502:physiology*; D013629:Tamoxifen / Q000008:administration & dosage / Q000494:pharmacology; D014410:Tumor Stem Cell Assay
D011960:Receptors, Estrogen; D013629:Tamoxifen; D004958:Estradiol