title: Novel interactions of vitamin E and estrogen in breast cancer.
abstract: The prevention of breast cancer through dietary modification is an active area of clinical and epidemiological research. It has been proposed that dietary supplementation of vitamin E may reduce a woman's risk of developing breast cancer. However, the exact mechanism remains unknown. alpha-Tocopherol is the most biologically active form of vitamin E. We investigated the effect of vitamin E (alpha-tocopherol) on breast cancer cell growth. A dose-dependent inhibition of cell proliferation was found in estrogen receptor (ER)-positive cells showing a potent suppression of growth at 100 microM vitamin E in MCF-7 (53%) and T47D (75%) cells. Vitamin E reduced significantly the response of both cell lines to estrogen (10 nM), and cell proliferation was decreased in MCF-7 and T47D cells by 69% and 84%, respectively. No growth inhibition was observed when cells were grown in the absence of estrogen. Vitamin E altered and decreased the growth inhibition induced by tamoxifen (10 microM) in MCF-7 (33%) and T47D (54%) cells. In addition, the immunostaining of ER of MCF-7 cells was reduced by 30% in the presence of vitamin E, suggesting an effect of vitamin E on the expression of ER. This provides evidence that vitamin E may inhibit ER-positive cell growth by altering the cellular response to estrogen.
authors.affiliation: Division of Hematology/Oncology, Department of Medicine, University of California at Los Angeles, School of Medicine 90095-1678, USA. HChamras@hotmail.com
authors.forename: Hilda
authors.initials: H
authors.lastname: Chamras
authors.forename: Sanford H
authors.initials: SH
authors.lastname: Barsky
authors.forename: Ani
authors.initials: A
authors.lastname: Ardashian
authors.forename: Daniel
authors.initials: D
authors.lastname: Navasartian
authors.forename: David
authors.initials: D
authors.lastname: Heber
authors.forename: John A
authors.initials: JA
authors.lastname: Glaspy
mesh_terms: D018931:Antineoplastic Agents, Hormonal / Q000037:antagonists & inhibitors; D001943:Breast Neoplasms / Q000453:epidemiology / Q000378:metabolism / Q000517:prevention & control*; D002455:Cell Division / Q000187:drug effects*; D019587:Dietary Supplements; D004305:Dose-Response Relationship, Drug; D004967:Estrogens / Q000378:metabolism*; D005260:Female; D006801:Humans; D011960:Receptors, Estrogen / Q000378:metabolism*; D013629:Tamoxifen / Q000037:antagonists & inhibitors; D014407:Tumor Cells, Cultured; D014810:Vitamin E / Q000008:administration & dosage* / Q000494:pharmacology; D014815:Vitamins / Q000008:administration & dosage* / Q000494:pharmacology; D024502:alpha-Tocopherol / Q000008:administration & dosage / Q000494:pharmacology
chemical_list: D018931:Antineoplastic Agents, Hormonal; D004967:Estrogens; D011960:Receptors, Estrogen; D014815:Vitamins; D013629:Tamoxifen; D014810:Vitamin E; D024502:alpha-Tocopherol