Table of Contents
ISRN Endocrinology
Volume 2014 (2014), Article ID 317398, 8 pages
http://dx.doi.org/10.1155/2014/317398
Research Article

Thyroid Hormone Status Interferes with Estrogen Target Gene Expression in Breast Cancer Samples in Menopausal Women

1Department of Biological Science, São Paulo Federal Institute (IFSP), 18136-540 São Roque, SP, Brazil
2Department of Internal Medicine, Division of Endocrinology and Metabolism, UNESP, 18618-000 Botucatu, SP, Brazil

Received 11 November 2013; Accepted 11 January 2014; Published 20 February 2014

Academic Editors: J. Pachucki, V. Pezzi, and D. F. Skafar

Copyright © 2014 Sandro José Conde et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

We investigated thyroid hormone levels in menopausal BrC patients and verified the action of triiodothyronine on genes regulated by estrogen and by triiodothyronine itself in BrC tissues. We selected 15 postmenopausal BrC patients and a control group of 18 postmenopausal women without BrC. We measured serum TPO-AB, TSH, FT4, and estradiol, before and after surgery, and used immunohistochemistry to examine estrogen and progesterone receptors. BrC primary tissue cultures received the following treatments: ethanol, triiodothyronine, triiodothyronine plus 4-hydroxytamoxifen, 4-hydroxytamoxifen, estrogen, or estrogen plus 4-hydroxytamoxifen. Genes regulated by estrogen (TGFA, TGFB1, and PGR) and by triiodothyronine (TNFRSF9, BMP-6, and THRA) in vitro were evaluated. TSH levels in BrC patients did not differ from those of the control group (1.34 ± 0.60 versus 2.41 ± 1.10 μU/mL), but FT4 levels of BrC patients were statistically higher than controls (1.78 ± 0.20 versus 0.95 ± 0.16 ng/dL). TGFA was upregulated and downregulated after estrogen and triiodothyronine treatment, respectively. Triiodothyronine increased PGR expression; however 4-hydroxytamoxifen did not block triiodothyronine action on PGR expression. 4-Hydroxytamoxifen, alone or associated with triiodothyronine, modulated gene expression of TNFRSF9, BMP-6, and THRA, similar to triiodothyronine treatment. Thus, our work highlights the importance of thyroid hormone status evaluation and its ability to interfere with estrogen target gene expression in BrC samples in menopausal women.