Abstract 2389 Biophysical Characterization of Novel Modulators of PRL3

As regulators of cellular phosphorylation, a key component of cellular signaling, kinases and phosphatase are relevant targets for the development of therapeutics against diseases characterized by aberrant phosphorylation. Protein Tyrosine Phosphatase 4A3 (PTP4A3), also known as the Phosphatase of Regenerating Liver 3 or PRL3, has recently emerged as a relevant modulator of several pathways leading to diseases, including many cancers, cancer metastasis, endometriosis, and others. Despite its connection to known disease pathways, little is actually known about its particular role in these pathways. There are currently no well-established PRL3 inhibitor/binders that can be used to probe its function in the cell. This project focuses broadly on understanding PRL3s function by finding activity modulators. Recently, we have identified three new small molecule inhibitors that also bind PRL3. These drugs (GB0002, GB0003, and GB0004) were identified through in vitro screening of top hits from a computational screen of six million purchasable compounds. This preliminary assay showed inhibitory effects on PRL3 activity and are promising candidates to further develop into therapeutics or as research tools to understand PRL3 biology. Using a synthetic phosphatase substrate, DiFMUP, we show that PRL3 activity is reduced by these compounds in a dose-dependent manner. Additionally, NMR on the three protein-drug complexes confirm their binding. Chemical shift perturbation was observed on 15N-HSQC spectra relative to the apo protein's fingerprint spectrum. ITC studies will also be done to further characterize the binding of these molecules to PRL3. These molecules provide additional scaffolds to explore for the development of effective PRL3 inhibitors, in addition to already identified molecules from a previous FDA-approved panel screen. Further studies will evaluate the binding mechanism of these molecules through structure determination by NMR as well as structure-activity relationship studies. The ultimate goal of this project is to better understand the structure and function of PRL3 and to identify effective modulators and characterize their inhibition and binding mechanisms. This project was partially funded by start up funds from the department of Biochemistry, Chemistry, and Physics of the College of Science and Mathematics at Georgia Southern University.