Chemistry-based enzyme detection and inhibition in epigenetics

Increasing evidence supports the significant role of epigenetic modifications in regulation of gene expression. Aberrant activity of the responsible chromatin-remodeling enzymes has been linked to serious pathologies such as inflammation and cancer. In her dissertation Marilena Ourailidou focuses on the development of novel tools to detect protein modifications as well as small-molecule inhibitors with potential therapeutic properties. More specifically, she introduces the oxidative Heck reaction as an efficient chemoselective bioorthogonal reaction for coupling of arylboronic acids to protein-bound alkenes and its successful application in in vitro monitoring of protein acylation. Additionally, photoswitchable histone deacetylase (HDAC) inhibitors were developed as potential antitumor agents and evaluated for their potency against HDAC isoforms and viability of cancer cells, with one compound exhibiting very promising results in its photoactivated cis form. Azobenzene analogues of the clinically-used HDAC1-3 inhibitor Entinostat were also designed and tested for their effect on macrophage inflammatory responses in an attempt to elucidate the role of HDAC1-3 in such pathways. Notifying, one analogue, that inhibited all three isoforms, displayed an improved anti-inflammatory profile in comparison to the parental agent, underlying that maintenance of inhibition through HDAC1-3 is required for the desirable pharmacological effects. Finally, Ourailidou describes her efforts on developing activity-based functionalized probes for detection of human recombinant and endogenous lysine-specific demethylase-1 (LSD1) activity. In all cases dose-dependent labeling was achieved while control experiments supported an activity-based profile. However, the effects on labeling upon treatment with LSD1 inhibitors were inconclusive and require further investigation of the mechanism of action of such probes.

Thesis

Promotors: Prof.dr. H.J. Haisma and Prof.dr. F.J. Dekker