Structural and Molecular Mechanisms of Cytokine-Mediated Endocrine Resistance in Human Breast Cancer Cells.
Stender, J.D., Nwachukwu, J.C., Kastrati, I., Kim, Y., Strid, T., Yakir, M., Srinivasan, S., Nowak, J., Izard, T., Rangarajan, E.S., Carlson, K.E., Katzenellenbogen, J.A., Yao, X.Q., Grant, B.J., Leong, H.S., Lin, C.Y., Frasor, J., Nettles, K.W., Glass, C.K.(2017) Mol Cell 65: 1122-1135.e5
- PubMed: 28306507 
- DOI: https://doi.org/10.1016/j.molcel.2017.02.008
- Primary Citation of Related Structures:  
5U2B, 5U2D - PubMed Abstract: 
Human breast cancers that exhibit high proportions of immune cells and elevated levels of pro-inflammatory cytokines predict poor prognosis. Here, we demonstrate that treatment of human MCF-7 breast cancer cells with pro-inflammatory cytokines results in ER¦Á-dependent activation of gene expression and proliferation, in the absence of ligand or presence of?4OH-tamoxifen (TOT). Cytokine activation of ER¦Á and endocrine resistance is dependent on phosphorylation of ER¦Á at S305 in the hinge domain. Phosphorylation of S305 by IKK¦Â establishes an ER¦Á cistrome that substantially overlaps with the estradiol (E2)-dependent ER¦Á cistrome. Structural analyses suggest that S305-P forms a charge-linked bridge with the C-terminal F domain of ER¦Á that enables inter-domain communication and constitutive activity from the N-terminal coactivator-binding site, revealing the structural basis of endocrine resistance. ER¦Á therefore functions as a transcriptional?effector of cytokine-induced IKK¦Â signaling, suggesting a mechanism through which the tumor microenvironment controls tumor progression and endocrine resistance.
Organizational Affiliation: 
Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093, USA.