Novel interactions of vitamin E and estrogen in breast cancer.
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.
Chamras
Hilda
H
Division of Hematology/Oncology, Department of Medicine, University of California at Los Angeles, School of Medicine 90095-1678, USA. HChamras@hotmail.com
Barsky
Sanford H
SH
Ardashian
Ani
A
Navasartian
Daniel
D
Heber
David
D
Glaspy
John A
JA
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
D018931:Antineoplastic Agents, Hormonal; D004967:Estrogens; D011960:Receptors, Estrogen; D014815:Vitamins; D013629:Tamoxifen; D014810:Vitamin E; D024502:alpha-Tocopherol