title: Effects of toremifene and its main metabolites on growth of breast cancer cell lines.
abstract: The effects of toremifene, an antiestrogen, and its two main metabolites (4-hydroxy- and N-desmethyltoremifene) on cell proliferation have been tested in a series of breast cancer cell lines, with positive (MCF7, ZR 75.1, T47D, 734B) or negative steroid receptor status (MDA-MB 231, BT20). Drug effects were evaluated at concentrations similar to those obtained in breast cancer patients on toremifene treatment, and in the presence or absence of estradiol. Results showed that, for both positive and negative cell lines, high concentrations of the antiestrogens (10(-6)M) were inhibitory, while lower doses (10(-7)M, 10(-8)M) were stimulatory. These data confirm the biphasic behaviour of toremifene and its derivatives. In terms of a clinical application of toremifene, these results seem to suggest that while high doses of toremifene and its derivatives might be therapeutic, lower concentrations might stimulate cell growth and enhance tumor progression.
authors.affiliation: Oncologia Sperimentale, C-Instituto Nazionale Tumori Milano, Italy.
authors.forename: D
authors.initials: D
authors.lastname: Coradini
authors.forename: A
authors.initials: A
authors.lastname: Biffi
authors.forename: V
authors.initials: V
authors.lastname: Cappelletti
authors.forename: G
authors.initials: G
authors.lastname: Di Fronzo
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D001943:Breast Neoplasms / Q000737:chemistry / Q000188:drug therapy*; D002455:Cell Division / Q000187:drug effects; D004347:Drug Interactions; D004354:Drug Screening Assays, Antitumor; D004958:Estradiol / Q000494:pharmacology; D006801:Humans; D011987:Receptors, Steroid; D013629:Tamoxifen / Q000031:analogs & derivatives* / Q000494:pharmacology; D017312:Toremifene; D014407:Tumor Cells, Cultured
chemical_list: D000970:Antineoplastic Agents; D011987:Receptors, Steroid; D013629:Tamoxifen; C062264:N-desmethyltoremifene; D004958:Estradiol; D017312:Toremifene; C062262:4-hydroxytoremifene