Abstract 2907: Targeting the epigenetic regulator KAT2a in cancer

Gene expression frequently requires the dynamic remodelling of the chromatin architecture to orchestrate the assembly of transcriptional protein complexes at the promoter sites of DNA. Chromatin remodelling complexes are multicomponent proteins that facilitate reorganisation of chromatin structure using the energy derived from ATP hydrolysis, and as a result play a pivotal role in controlling gene expression. Mammalian SWI/SNF complexes are examples of chromatin remodelling complexes with multiple roles in maintaining genome stability. It is estimated that 19.6% of all human tumours have mutations in SWI/SNF complexes, leading to the deregulation of gene expression as an early driver of carcinogenesis. Our interest in developing novel treatments for renal cancer focused on the role of the chromatin remodelling complex, PBAF. The BAF180 component of PBAF is mutated in 40 % of clear cell renal carcinomas and its loss is an early event in renal cell tumorigenesis. We performed an siRNA based high throughput screen to identify genes associated with genome stability that were synthetically lethal with the loss of BAF180 and identified KAT2a as a potential druggable target. KAT2a is a protein that also functions in the regulation of gene expression as a component of the SAGA histone modifying complex. It is a multifunctional protein that can both ‘read9 and ‘write9 acetylation marks on histone proteins through its bromodomain and a histone acetyltransferase domain respectively. We will describe our efforts to establish suitable assays to support the discovery of selective inhibitors of the bromodomain of KAT2a. The work will include the establishment of a high throughput assay to measure compound binding, crystallographic characterisation of small molecule inhibitors of the bromodomain, and our initial studies towards the target validation of the bromodomain to recapitulate the synthetic lethality observed with depletion of BAF180. Citation Format: Andrea Gunnell, Jessica Downs, Lewis Pennicott, Kay Osborn, Darren Le Grand, Katie Duffell, Hitesh Patel, Jessica Hudson, Jessica R. Booth, Simon Ward. Targeting the epigenetic regulator KAT2a in cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2907.