Label-free sensing and atomic force spectroscopy for the characterization of protein-DNA and protein-protein interactions: application to estrogen receptors

In this paper we describe a new surface plasmon resonance (SPR) biosensor dedicated to potential estrogenic compounds prescreening, by developing an estrogen receptor (ER) specific DNA chip. Through the covalent binding of a DNA strain wearing the estrogen response element (ERE) to an activated 6-mercapto-1-hexadecanoic acid and 11-mercapto-1-undecanol self-assembled monolayer on gold surface, the SPR biosensor allows to detect specifically, quickly, and without any labeling the binding of ER in the presence of estrogen. In parallel, we investigated the ER interaction with itself, in order to study the formation of ER dimer apparently needed to activate the gene expression through ERE interaction. For that, we engaged force spectroscopy experiments that allowed us to prove that ER needs estrogen for its dimerization. Moreover, these ER/ER intermolecular measurements enabled to propose an innovative screening tool for anti-estrogenic compounds, molecules of interest for hormono-dependent cancer therapy.