This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Chen, J. Articles by Thompson, L. U. Search for Related Content PubMed PubMed Citation Articles by Chen, J. Articles by Thompson, L. U.

Dietary Flaxseed Enhances the Inhibitory Effect of Tamoxifen on the Growth of Estrogen-Dependent Human Breast Cancer (MCF-7) in Nude Mice

Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Toronto, Canada

Purpose: This study determined the effect of 10% dietary flaxseed (FS) and tamoxifen (TAM), alone and in combination, on the growth of estrogen-dependent human breast cancer (MCF-7) in athymic mice with or without 17ß-estradiol (E2) supplementation.

Experimental Design: Ovariectomized mice received injection with MCF-7 cells, were implanted with an E2 pellet (1.7 mg), and fed the basal diet (BD). When tumor reached 40 mm², the E2 implant was removed, and mice were randomized to the following groups and maintained at either low (E2 pellet removed) or high E2 level (new E2 pellet implanted) for 6 weeks: (a) positive control with new E2 pellet, fed BD, (b) negative control with no E2 implant, fed BD, (c) TAM group with TAM pellet (5 mg) implant, fed BD, (d) FS group fed 10% FS, (e) FS+TAM group with TAM implant, fed 10% FS. Tumor growth was monitored weekly.

Results: At low E2 level, FS regressed the pretreatment tumor size by 74%. TAM regressed tumor initially but later induced an increase so that the tumor size was finally similar to the pretreatment size. A tumor regression >53% was induced by FS+TAM than by TAM alone. At high E2 level, FS, TAM, and FS+TAM inhibited the tumor growth by 22, 41, and 50%, respectively, compared with the positive control. Decreased tumor size was attributable to reduced tumor cell proliferation and increased apoptosis.

Conclusions: FS inhibited the growth of human estrogen-dependent breast cancer and strengthened the tumor-inhibitory effect of TAM at both low and high E2 levels.

This article has been cited by other articles:

				J. Chen, K. A. Power, J. Mann, A. Cheng, and L. U. Thompson Flaxseed Alone or in Combination with Tamoxifen Inhibits MCF-7 Breast Tumor Growth in Ovariectomized Athymic Mice with High Circulating Levels of Estrogen Experimental Biology and Medicine, September 1, 2007; 232(8): 1071 - 1080. [Abstract] [Full Text] [PDF]

				C. Duffy, K. Perez, and A. Partridge Implications of Phytoestrogen Intake for Breast Cancer CA Cancer J Clin, September 1, 2007; 57(5): 260 - 277. [Abstract] [Full Text] [PDF]

				S. M. Sacco, K. A. Power, J. Chen, W. E. Ward, and L. U. Thompson Interaction of Sesame Seed and Tamoxifen on Tumor Growth and Bone Health in Athymic Mice Experimental Biology and Medicine, June 1, 2007; 232(6): 754 - 761. [Abstract] [Full Text] [PDF]

				M. Bergman Jungestrom, L. U. Thompson, and C. Dabrosin Flaxseed and Its Lignans Inhibit Estradiol-Induced Growth, Angiogenesis, and Secretion of Vascular Endothelial Growth Factor in Human Breast Cancer Xenografts In vivo Clin. Cancer Res., February 1, 2007; 13(3): 1061 - 1067. [Abstract] [Full Text] [PDF]

				L. U. Thompson, J. M. Chen, T. Li, K. Strasser-Weippl, and P. E. Goss Dietary Flaxseed Alters Tumor Biological Markers in Postmenopausal Breast Cancer Clin. Cancer Res., May 15, 2005; 11(10): 3828 - 3835. [Abstract] [Full Text] [PDF]