Non-nuclear estrogen receptor α signaling promotes cardiovascular protection but not uterine or breast cancer growth in mice
Ken L. Chambliss, … , Benita S. Katzenellenbogen, Philip W. Shaul
Ken L. Chambliss, … , Benita S. Katzenellenbogen, Philip W. Shaul
Published June 23, 2010
Citation Information: J Clin Invest. 2010;120(7):2319-2330. https://doi.org/10.1172/JCI38291.
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Non-nuclear estrogen receptor α signaling promotes cardiovascular protection but not uterine or breast cancer growth in mice

Abstract

Steroid hormone receptors function classically in the nucleus as transcription factors. However, recent data indicate that there are also non-nuclear subpopulations of steroid hormone receptors, including estrogen receptors (ERs), that mediate membrane-initiated signaling of unclear basis and significance. Here we have shown that an estrogen-dendrimer conjugate (EDC) that is excluded from the nucleus stimulates endothelial cell proliferation and migration via ERα, direct ERα-Gαi interaction, and endothelial NOS (eNOS) activation. Analysis of mice carrying an estrogen response element luciferase reporter, ER-regulated genes in the mouse uterus, and eNOS enzyme activation further indicated that EDC specifically targets non-nuclear processes in vivo. In mice, estradiol and EDC equally stimulated carotid artery reendothelialization in an ERα- and G protein–dependent manner, and both agents attenuated the development of neointimal hyperplasia following endothelial injury. In contrast, endometrial carcinoma cell growth in vitro and uterine enlargement and MCF-7 cell breast cancer xenograft growth in vivo were stimulated by estradiol but not EDC. Thus, EDC is a non-nuclear selective ER modulator (SERM) in vivo, and in mice, non-nuclear ER signaling promotes cardiovascular protection. These processes potentially could be harnessed to provide vascular benefit without increasing the risk of uterine or breast cancer.

Authors

Ken L. Chambliss, Qian Wu, Sarah Oltmann, Eddy S. Konaniah, Michihisa Umetani, Kenneth S. Korach, Gail D. Thomas, Chieko Mineo, Ivan S. Yuhanna, Sung Hoon Kim, Zeynep Madak-Erdogan, Adriana Maggi, Sean P. Dineen, Christina L. Roland, David Y. Hui, Rolf A. Brekken, John A. Katzenellenbogen, Benita S. Katzenellenbogen, Philip W. Shaul

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Figure 3

Non-nuclear ER activation stimulates endothelial cell proliferation and migration via ER, Gαi, Src, and eNOS and through direct interaction of the receptor with Gαi.

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Non-nuclear ER activation stimulates endothelial cell proliferation and ...
(A) Cell number was determined after 48 hours treatment with vehicle or dendrimer controls, or 10–8 M E2 or EDC (10–8 M E2 equivalents), in the absence or presence of 10–5 M ICI 182,780, 100 ng/ml pertussis toxin, 10 μM PP2, or 2 mM L-NAME. (B and C) To evaluate migration, cells were wounded and treated as in A for 24 hours, and the number of cells that had migrated past the wound edge per high-power field was quantified. Images in B are representative optical fields. In A and C, values are expressed as percent of control treatment, mean ± SEM, n = 6. *P < 0.05 versus control; †P < 0.05 versus E2 or EDC alone. (D) Migration was assessed in BAECs transfected with sham plasmid (control), plasmid encoding the dominant-negative mutant receptor ERαΔ250–260, or plasmid that expressed a peptide consisting of amino acids 251–260 of the receptor (ERα251–260). Treatments were vehicle (basal), 10–8 M E2, EDC (10–8 M E2 equivalents), 100 ng/ml VEGF, or 10% serum for 24 hours. Summary data are provided in E. White bars, cells transfected with sham plasmid (control); gray bars, cells transfected with the mutant receptor ERαΔ250–260; black bars, cells expressing ERα251–260 peptide. The approximately 50% attenuation of the migration responses to E2 and EDC caused by the interventions is consistent with the transfection efficiency attained under these conditions. Values are mean ± SEM, n = 6. *P < 0.05 versus basal; †P < 0.05 versus control.