Our long term objective is to understand the biochemical mechanisms and physiological significance of estrogen receptor alpha (ERalpha) and estrogen receptor beta (ERbeta) activation of gene expression at target genes with AP-1 or CRE sites (AP-1/CRE). Such AP1/CRE target genes, including cyclin D1, lack classical estrogen response elements (EREs) but are nonetheless induced by ER action. ERa activates AP-1/CRE primarily with estrogen and ERbeta, in contrast, only with antiestrogens. To understand how ERs work at AP- 1/CRE, we will exploit a mutation that makes both ERs selectively and dramatically superactive at AP-1/CRE sites and only with estrogen. ER induction of AP-1/CRE target genes may underlie some of the most profound effects of estrogen, those on cellular proliferation in the mammary gland and reproductive track. We find that the selectively superactive ERalpha, K206A, drives overexpression of cyclin D1 and hyper-proliferation in the genital track of transgenic female mice. K206A also drives overexpression of cyclin D1 in cultured cells, but the presence of ERa inhibits such activation. We thus wish to explore the hypothesis that ERa action at AP-1/CRE elements drives some of the proliferative effects of estrogen, especially in the mammary gland and reproductive track, and that the presence of ERbeta, by inhibiting activation of AP-1/CRE targets, modulates these effects.
Our aims are:
Aim 1. Determine the molecular mechanisms of ERalpha-estrogen activation and K206A super-activation at AP-1/CRE elements.
Aim 2. Determine the physiological role of ERalpha activation of AP-1/CRE elements in the mammary gland.
Aim 3. Determine the mechanism whereby ERbeta inhibits the ability of ERalpha and ERalpha K206A to activate at AP-I/CRE with estrogen.
Aim 4. Determine whether ERbeta, which inhibits ERbeta stimulation of cyclin D1 gene expression, also inhibits cellular proliferation mediated by ERalpha. If successful, these studies will test the hypothesis that ERalpha action at AP-1/CRE target genes mediates proliferation, and that ERbeta modulates such action. The knowledge gained will be greatly useful for developing a new generation of drugs to prevent estrogen induced cancers.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
5R01CA080210-08
Application #
7009659
Study Section
Reproductive Endocrinology Study Section (REN)
Program Officer
Sathyamoorthy, Neeraja
Project Start
1999-01-08
Project End
2008-01-31
Budget Start
2006-02-01
Budget End
2007-01-31
Support Year
8
Fiscal Year
2006
Total Cost
$312,893
Indirect Cost
Name
University of California San Francisco
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
094878337
City
San Francisco
State
CA
Country
United States
Zip Code
94143
Hodges-Gallagher, Leslie; Valentine, Cathleen D; El Bader, Suzy et al. (2008) Estrogen receptor beta increases the efficacy of antiestrogens by effects on apoptosis and cell cycling in breast cancer cells. Breast Cancer Res Treat 109:241-50
Zavodovskaya, Marianna; Campbell, Michael J; Maddux, Betty A et al. (2008) Nordihydroguaiaretic acid (NDGA), an inhibitor of the HER2 and IGF-1 receptor tyrosine kinases, blocks the growth of HER2-overexpressing human breast cancer cells. J Cell Biochem 103:624-35
Hodges-Gallagher, Leslie; Valentine, Cathleen D; Bader, Suzy El et al. (2007) Inhibition of histone deacetylase enhances the anti-proliferative action of antiestrogens on breast cancer cells and blocks tamoxifen-induced proliferation of uterine cells. Breast Cancer Res Treat 105:297-309
Webb, Paul; Nguyen, Phuong; Kushner, Peter J (2003) Differential SERM effects on corepressor binding dictate ERalpha activity in vivo. J Biol Chem 278:6912-20
Liu, Meng-Min; Albanese, Chris; Anderson, Carol M et al. (2002) Opposing action of estrogen receptors alpha and beta on cyclin D1 gene expression. J Biol Chem 277:24353-60
Lopez, G N; Turck, C W; Schaufele, F et al. (2001) Growth factors signal to steroid receptors through mitogen-activated protein kinase regulation of p160 coactivator activity. J Biol Chem 276:22177-82
Feng, W; Webb, P; Nguyen, P et al. (2001) Potentiation of estrogen receptor activation function 1 (AF-1) by Src/JNK through a serine 118-independent pathway. Mol Endocrinol 15:32-45
Webb, P; Nguyen, P; Valentine, C et al. (1999) The estrogen receptor enhances AP-1 activity by two distinct mechanisms with different requirements for receptor transactivation functions. Mol Endocrinol 13:1672-85