Unique Breast Cancer Cell Model for Studying Reported Functions of Membrane-Localized Estrogen Receptor (Alpha)

摘要

We previously developed a cell line system in which exogenous expression of estrogen receptor alpha (ERalpha) in an ERalpha-negative cell line resulted in ERalpha-mediated signaling and proliferation. We previously reported generation of a cell lines that expressed ERalpha only in the cytoplasm (c ERalpha) to characterize the putative cytoplasmic (non-genomic) function of ERalpha. However, while we found that cERa was not able to stimulate genomic ER action, and found interesting differences in estrogen- mediated downregulation of cERalpha, we were unable to show that this receptor could activate short-term non-genomic signaling. Since last year we have now started studying a membrane-targeted ERalpha (rhodopsin fused to ERalpha). We have generated stable cells expressing this receptor and show that this form of Era is exclusively localized to the plasma membrane, and also estrogen is able to rapidly activate ERK1/2 in these cells. We have now also generated MCF-7 or MCF-7/HER2 cells overexpressing either cERalpha or rho- ERalpha and are currently examining the effect of this receptor on hormone response in these cells. We will finish the study using a one-year no cost extension.