Abstract 4784: Selective bioluminogenic HDAC activity assays for profiling HDAC inhibitors

Abstract

Abstract Histone deacetylases (HDACs) play critical roles in the regulation of gene transcription and cell signaling events by deacetylating histones and other important non-histone substrates. Aberrant increases in HDAC enzyme activities are therefore implicated in a number of human infirmities, including cancers, metabolic disease and neurodegeneration. Fortunately, HDAC enzymes represent attractive pharmacological targets because they are readily tractable with small molecule inhibitors. In fact, several HDAC inhibitors (HDACi) have recently proceeded through (or are near) the FDA approval process for the treatment of hematologic malignancies. However, the promise of clinical HDACi therapy has been hampered by significant dose-limiting toxicities. These off-target effects have led to a renewed focus on basic HDAC biology and the development of isoenzyme-specific HDAC inhibitors which could avoid off-target effects. To help facilitate the discovery of compounds with better defined selectivity profiles, we have developed lysine deacetylase assays that selectively measure specific isoenzyme activities in cells, extracts, or purified recombinant preparations. These assays are based on substrates that are selective due to a combination of extended peptide sequence and novel chemical modifications. Deacetylase activity is measured by delivering a single, pro-luminogenic, homogeneous assay reagent to assay wells, resulting in luminescence proportional to HDAC activity. In addition to being isoenzyme selective, these novel substrates are cell permeable allowing for lytic and non-lytic cell-based HDAC assays. Lastly, these assays are also fully compatible with fluorescent viability and/or cytotoxicity assays. This provides additional flexibility for multiplexed formats which examine not only selective HDAC inhibition, but the functional consequences they exert on cell health. Citation Format: Kevin R. Kupcho, Nathan J. Evans, Andrew L. Niles, Thomas A. Kirkland, Dan F. Lazar. Selective bioluminogenic HDAC activity assays for profiling HDAC inhibitors. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4784. doi:10.1158/1538-7445.AM2014-4784