ERα17p, an ERα P295-T311 Fragment, Modifies the Migration of Breast Cancer Cells, Through Actin Cytoskeleton Rearrangements

Recently, our knowledge on estrogen receptor alpha (ER alpha) functions and fate has progressed: ERa enters in repeated transcription-modulating cycles (nucleus/cytoplasm/membrane trafficking processes and proteasomal degradation) that are governed by specific protein-protein interactions. Receptor fragments, especially those resulting from the proteolysis of its ligand binding domain, as well as corresponding synthetic peptides, have been studied with respect to their estrogenic/antiestrogenic potency. A peptide, corresponding to the human ER alpha P-295-T-311 sequence (ER alpha 17p) has been shown to alter breast cancer cell fate, triggering proliferation, or apoptosis. The aim of this work was to explore the effect of ER alpha 17p on breast cancer cell migration and actin cytoskeleton dynamics and further analyze the mechanism of its membrane action. We show that ER alpha 17p increases (MCF-7 and SK-BR-3 cells) or decreases (T47D and MDA-MB-231 cells) migration of breast cancer cells, in an ER alpha-independent manner, by mechanism(s) depending on Rho/ROCK and PI3K/Akt signaling pathways. Moreover, the peptide enhances the association of both estrogens and androgens to membranes and modifies cell migration, induced by E-2-BSA. Additionally, initial evidence of a possible agonistic action of the peptide on GPR30 is also provided. ER alpha 17p can be considered as a cell migration-modulator and could therefore constitute a therapeutic challenge, even in anti-estrogen-resistant tumors. J. Cell. Biochem. 112: 3786-3796, 2011. (C) 2011 Wiley Periodicals, Inc.