EWS-FLI1 as a molecular target: Small molecule inhibitors for a disordered protein
Abstract
Ewing sarcoma family of tumors (ESFT) consists of highly malignant tumors of the bone and soft tissue. Ninety-five percent of cases contain a balanced t(11;22) or t(21;22) rearrangement, combining the amino-terminus of EWS to the carboxy-terminus of FLI1 or ERG, which contain the highly conserved ets DNA binding domain. As the EWS-FLI1 protein is found only in ESFT cells and its expression is required for the oncogenic phenotype, it presents a promising molecular target for anti-cancer therapies. EWS-FLI1 is a hydrophobic disordered protein with unknown three-dimensional structure, precluding standard structure-based drug design. RNA Helicase A (RHA) enhances EWS-FLI1 driven oncogenesis and interruption of this protein-protein complex validates this interaction as a unique therapeutic target. Surface plasmon resonance screening identified compounds that bind to EWS-FLI1, including a lead compound that induces apoptosis in ESFT cells and reduces the growth of xenografts. Our compound, YK-4-279, has a chiral center and can be separated into enantiomers, only one of which is able to specifically target the protein-protein interaction. This work is significant for its identification of a single enantiomer effect upon a protein-protein interaction suggesting that small molecule targeting of intrinsically disordered proteins can be highly specific. Given the challenges of drug design targeted to EWS-FLI1, we proposed that characterization of the physical interaction points between EWS-FLI1 and RHA would allow us to better alter the lead compound to block this protein-protein interaction. While full length EWS-FLI1 is able to pull down RHA, fragments of the protein are not. Although we can successfully crosslink EWS-FLI1 and RHA, we have yet to identify what region of EWS-FLI1 is involved. We are able to show specific regions of order and disorder of EWS-FLI1, which may lead to the identification of the binding site for YK-4-279. The development of higher-throughput methods for testing small molecules that bind to or inhibit EWS-FLI1 function will allow us to further investigate protein structure and function. These data are a contribution to the future development of small molecules in an era where novel approaches to cancer therapy are critical for improving patient care.
Description
Ph.D.
Permanent Link
http://hdl.handle.net/10822/557903Date Published
2012Subject
Metadata
Show full item recordRelated items
Showing items related by title, author, creator and subject.
-
Amino-acid derived 1,2 benzisothiazolinone derivatives as novel small molecule antifungal inhibitors: Characterization and identification of potential genetic targets
(Georgetown University, 2011)A steady increase in the incidence of fungal infections has been observed over the past few decades, and treatment remains challenging especially for immuno-compromised populations. Identification of the ideal therapeutic ... -
INVESTIGATION OF PROTEIN AND SMALL-MOLECULE SELF-ASSOCIATION IN THE CONTEXT OF C-MYC/MAX INHIBITION
(Georgetown University, 2016)The intrinsically disordered c-Myc oncoprotein is deregulated in ~70% of human cancers and is considered a promising but challenging drug target. To regulate transcription, c-Myc undergoes coupled folding and binding with ... -
SMALL MOLECULE BINDING OF INTRINSICALY DISORDERED PROTEINS: MULTIPLE BINDERS ON MULTIPLE SITES
(Georgetown University, 2009)Intrinsically disordered (ID) proteins lack a stable tertiary structure and exist in an ensemble of rapidly inter-converting conformations. They are prevalent in human and other genomes, and are biologically active in ...
