Poster Presentation 26th Lorne Cancer Conference 2014

Targeting epigenetically driven leukaemias through inhibition of the acetyltransferase monocytic leukaemia zinc finger protein (MOZ) (#144)

Hendrik Falk 1 2 3 , Theresa Connor 2 , Hong Yang 2 , Karen J Loft 1 2 , Joanne L Alcindor 1 2 3 , George Nikolakopoulos 1 2 3 , John D Bentley 4 , Meghan K Hattarki 4 , Olan Dolezal 4 , James M Murphy 2 , John P Parisot 1 2 , Brendon J Monahan 1 4 , Thomas S Peat 1 4 , Tim Thomas 2 3 , Natalie Downer 2 , Bilal Sheikh 2 , David J Leaver 5 , Ben L Cleary 5 , Jonathan B Baell 5 , Ian P Street 1 2 3
  1. Cancer Therapeutics CRC, Bundoora, Victoria, Australia
  2. Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
  3. Department of Medical Biology, The University of Melbourne, Parkville, Victoria, Australia
  4. Materials Science and Engineering Division, CSIRO, Parkville, Australia
  5. Monash Institute of Pharmaceutical Sciences, Parkville, Australia

Modulation of epigenetic modifications is a promising approach in developing new therapies for cancers refractory to current treatments. Monocytic leukaemia zinc finger protein (MOZ) is member of the MYST family of histone acetyl transferases (HAT). Its members play a key role in regulating patterns of gene expression in proliferation, differentiation, and apoptosis. MOZ in particular has been implicated in the formation of haematopoietic stem cells during foetal development and their self-renewal in the adult organism. Deregulation of these processes can give rise to the formation of leukemic stem cells, rendering MOZ an excellent target candidate for treating myeloid leukaemia. Currently no small molecule MOZ-HAT inhibitors are available.

We have implemented a hit discovery campaign to identify small molecule inhibitors of MOZ-HAT activity. We developed a homogenous assay to detect the MOZ-catalysed acetylation of histone N-terminal peptides using antibodies specific for the acetylated lysine product. Signal amplification with AlphascreenTM technology delivered a high signal-to-background ratio and could be miniaturised easily. Importantly, the assay was able to measure activities not only of MOZ but also of related MYST family enzymes.

In a primary screening campaign of 243,000 lead-like small molecules we identified inhibitors from several chemical classes. Secondary assays were used to eliminate assay-interfering compounds and prioritise the hits. Using medicinal chemistry we have developed a series of reversibly binding compounds with low nanomolar Moz inhibition that are active in cellular assays. In summary, this study establishes a new high-throughput assay for HAT activity and provides the foundation for the development of a new class of drugs for the treatment of leukaemias.