title: Inhibition of postconfluent focus production in cultures of MCF-7 human breast cancer cells by 2,3,7,8-tetrachlorodibenzo-p-dioxin.
abstract: 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), a potent inducer of differentiation and an antiestrogen, is shown to suppress in vitro postconfluent cell accumulation in the estrogen-dependent MCF-7 human breast tumor cell line. This dose-responsive suppression is apparent by 14 days of exposure with an EC50 between 10(-10) and 10(-11) M TCDD, and is characterized by reduced cell density (approximately 60% of controls after 14 days). This was attributed to a reduced formation in TCDD-treated cultures of multicellular foci which are characteristic of cancer cell growth in vitro (less than 1/mm2 compared to control levels of 40/mm2). Preconfluent cell growth and viability of MCF-7 cells is not affected by 10(-9) M TCDD. These results suggest that the principle of TCDD's activity may be useful in the study and possibly the management of estrogen-dependent breast tumors.
authors.affiliation: Wadsworth Center for Laboratories and Research, New York State Department of Health, Albany 12201.
authors.forename: J F
authors.initials: JF
authors.lastname: Gierthy
authors.forename: D W
authors.initials: DW
authors.lastname: Lincoln
mesh_terms: D001943:Breast Neoplasms / Q000473:pathology*; D002449:Cell Aggregation / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D004147:Dioxins / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D006801:Humans; D000072317:Polychlorinated Dibenzodioxins / Q000494:pharmacology*; D014407:Tumor Cells, Cultured / Q000187:drug effects
chemical_list: D004147:Dioxins; D000072317:Polychlorinated Dibenzodioxins