Chimeric ligands that heterodimerize Hsp90 and estrogen receptor proteins

ORGN 678

Laurie Mottram, Megan M MacBride, mmm306@psu.edu, and Blake R. Peterson, brpeters@chem.psu.edu. Department of Chemistry, The Pennsylvania State University, 429 Chemistry Building, University Park, PA 16802
Heat shock protein 90 (Hsp90) is an abundant ATP-dependent cellular chaparone that facilitates the folding of estrogen receptors (ERs) and other oncogenic proteins involved in cancer proliferation. This protein is under intense investigation as a target of anticancer drugs because breast cancer cells contain Hsp90 in an activated high affinity conformation that is particularly susceptible to Hsp90 inhibitors. These inhibitors include the anticancer agent geldanamycin (GDM), which is thought to inhibit the proliferation of cancer cells in part by blocking agonist-induced release of steroid hormone receptors such as ERs from Hsp90. Here, we report the synthesis and biological evaluation of chimeric ligands derived from estrogens and GDM designed to heterodimerize ER and Hsp90 proteins. These compounds were found to enforce interactions between these proteins in vitro and uniquely affect the subcellular localization of ERalpha in a cancer cell line.