title: Effects of thyroid hormones on human breast cancer cell proliferation.
abstract: The involvement of estrogens in breast cancer development and growth has been well established. However, the effects of thyroid hormones and their combined effects with estrogens are not well studied. We investigated the response of human breast cancer cells to thyroid hormone, particularly the role of T3 in mediating cell proliferation and gene expression. We demonstrated that 17beta-estradiol (E2) or triiodothyronine (T3) promoted cell proliferation in a dose-dependent manner in both MCF-7 and T47-D cell lines. The E2- or T3-dependent cell proliferation was suppressed by co-administration of the ER antagonist ICI. We also demonstrated that T3 could enhance the effect of E2 on cell proliferation in T47-D cells. Using an estrogen response element (ERE)-mediated luciferase assay, we determined that T3 was able to induce the activation of ERE-mediated gene expression in MCF-7 cells, although the effects were much weaker than that induced by E2. These results suggest that T3 can promote breast cancer cell proliferation and increase the effect of E2 on cell proliferation in some breast cancer cell lines and thus that T3 may play a role in breast cancer development and progression.
authors.affiliation: Safety and Environmental Protection Directorate, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA.
authors.forename: Linda C
authors.initials: LC
authors.lastname: Hall
authors.forename: Eddie P
authors.initials: EP
authors.lastname: Salazar
authors.forename: Staci R
authors.initials: SR
authors.lastname: Kane
authors.forename: Nan
authors.initials: N
authors.lastname: Liu
mesh_terms: D001943:Breast Neoplasms / Q000209:etiology* / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D002453:Cell Cycle / Q000187:drug effects; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects*; D004357:Drug Synergism; D004958:Estradiol / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000494:pharmacology; D020847:Estrogen Receptor Modulators / Q000494:pharmacology; D047628:Estrogen Receptor alpha / Q000378:metabolism; D047629:Estrogen Receptor beta / Q000378:metabolism; D005260:Female; D000077267:Fulvestrant; D015870:Gene Expression / Q000187:drug effects; D017930:Genes, Reporter; D006801:Humans; D008156:Luciferases / Q000235:genetics; D037042:Thyroid Hormone Receptors beta / Q000378:metabolism; D014284:Triiodothyronine / Q000008:administration & dosage / Q000494:pharmacology*
chemical_list: D020847:Estrogen Receptor Modulators; D047628:Estrogen Receptor alpha; D047629:Estrogen Receptor beta; D037042:Thyroid Hormone Receptors beta; D014284:Triiodothyronine; D000077267:Fulvestrant; D004958:Estradiol; D008156:Luciferases