Design, synthesis and biological evaluation of new small-molecule modulators of proein lysine methyltransferases (PKMTs)

Histone lysine methyltransferases have crucial roles in a number of biological processes and human diseases by controlling gene expression and chromatin state. Within this family, the lysine methyltransferase G9a has emerged as critical player in several pathologic states, particularly because of its important role in the silencing of tumor suppressor genes and in the regulation of other chromatin events. The low number of G9a chemical probes suitable for cell-based and animal studies, as well as the limited chemical diversity demand for the development of new modulators. In this thesis, two different approaches aimed at the identification of novel chemotypes for the modulation of G9a are presented. On one hand, from a medicinal chemistry prospective, we considered the modification of the central core of the potent and selective inhibitor UNC0638, resulting in a 1,4-benzodiazepine derivative EML741. To validate the approach, we designed and synthesized a small set of ring-expanded derivatives and tested their activity in vitro. Peptide-based biochemical assays (AlphaLISA) validated our design, as compound EML741 preserves the activity of the parent compound. In fact, EML741 is a G9a competitive inhibitor with respect to substrate endowed with potent activity and selectivity. In addition, EML741 showed favorable physico-chemical properties as it is quite soluble and chemical stable in aqueous media, and exhibited a membrane permeability profile (PAMPA and PAMPA-BBB) better than the parent compound UNC0638... [edited by Author]