Novel Functions of EZH2 in Triple Negative Breast Cancer: Translation in to New Biomarker and Treatment Strategies

Abstract : In our first year of funding we have been able to identify 68 TNBC tissue samples from African women, and 60 TNBC from White women. All blocks were organized and paraffin embedded sections were stained with hematoxylin and eosin (H and E) and histologically evaluated. We successfully developed high density tissue microarrays with these cases. Furthermore, we have selected and optimized the antibodies against EZH2, p38, and H3K27me3 to use for immunohistochemical staining of these tissue microarrays. We are currently working on optimizing anti- AKT1. We have been able to characterize the protein-protein interactions (PPIs) between EZH2 and p38 and with AKT1. We successfully determined the kinetic and binding affinity of these PPIs using recombinant full length proteins. These results confirmed the direct interactions between EZH2 and p38 and AKT1 as well as the co-immunoprecipitations studies which showed that EZH2 binds to p38in both the nucleus and the cytoplasm of MDA-MB-231 cells. We will continue with biochemical and biophysical studies towards mapping the binding site and identifying the key residues essential for these PPIs.