14660 DOI 10.1007/s12672-014-0174-ORIGINAL PAPERGPER Mediates Estrogen-Induced Signaling and Proliferation in Human Breast Epithelial Cells and Standard and Malignant BreastAllison L. Scaling Eric R. Prossnitz Helen J. HathawayReceived: 15 November 2013 / Accepted: 14 March 2014 / Published online: ten April 2014 # Springer Science+Business Media New YorkAbstract 17-Estradiol (estrogen), by way of receptor binding and activation, is essential for mammary gland improvement. Estrogen stimulates epithelial proliferation inside the mammary gland, promoting ductal elongation and morphogenesis. As well as a developmental part, estrogen promotes proliferation in tumorigenic settings, particularly breast cancer. The proliferative effects of estrogen in the typical breast and breast tumors are attributed to estrogen receptor . Despite the fact that in vitro studies have demonstrated that the G protein-coupled estrogen receptor (GPER, previously known as GPR30) can modulate proliferation in breast cancer cells each positively and negatively according to cellular context, its part in proliferation in the intact standard or malignant breast remains unclear. Estrogen-induced GPER-dependent proliferation was assessed inside the immortalized nontumorigenic human breast epithelial cell line, MCF10A, and an ex vivo organ culture model employing human breast tissue from reduction mammoplasty or tumorresections. Stimulation by estrogen plus the GPER-selective agonist G-1 enhanced the mitotic index in MCF10A cells and proportion of cells inside the cell cycle in human breast and breast cancer explants, suggesting enhanced proliferation. Inhibition of candidate signaling pathways that may link GPER activation to proliferation revealed a dependence on Src, epidermal growth element receptor transactivation by heparin-bound EGF and subsequent ERK phosphorylation. Proliferation was not dependent on matrix metalloproteinase cleavage of membrane-bound pro-HB-EGF. The contribution of GPER to estrogen-induced proliferation in MCF10A cells and breast tissue was confirmed by the ability of GPERselective antagonist G36 to abrogate estrogen- and G-1-induced proliferation, plus the capacity of siRNA knockdown of GPER to minimize estrogen- and G-1-induced proliferation in MCF10A cells. This really is the first study to demonstrate GPERdependent proliferation in key regular and malignant human tissue, revealing a function for GPER in estrogen-induced breast physiology and pathology.Eric R. Prossnitz and Helen J. Hathaway equally contributed to this study. Electronic supplementary material The online version of this article (doi:ten.1007/s12672-014-0174-1) contains supplementary material, that is out there to authorized users. A. L. Scaling : E. R. Prossnitz : H.Chalcone Autophagy J.Endoproteinase Lys-C site Hathaway Cancer Investigation and Treatment Center, University of New Mexico School of Medicine, Albuquerque, NM, USA A.PMID:24025603 L. Scaling : E. R. Prossnitz : H. J. Hathaway (*) Department of Cell Biology Physiology, University of New Mexico Overall health Sciences Center, Albuquerque, NM 87131, USA e-mail: [email protected] Present Address: A. L. Scaling Division of Endocrinology, Metabolism and Diabetes Division, University of Colorado, Anschutz Medical Campus, Aurora, CO 80045, USAIntroduction Typical growth and differentiation from the breast are below tight endocrine control. This is highlighted by the truth that further improvement on the mammary gland rudiment will not be initiated until the gland is exposed to circulating 17-estradiol (E2) at puberty [16, 38].