Liganden-basiertes Wirkstoffdesign zur Targetaufklärung und Entwicklung neuartiger Transkriptionsmodulatoren

The studies encompassed three main and several side projects, of which only the major projects will be discussed within this summary. The first project dealt with the structural modification of previously in-house identified PPARβ/δ inverse agonists aimed for the generation of photoaffinity probes, which potentially should enable the resolution of the yet unknown binding mode of the two distinct compound classes via photoaffinity labeling. While the modulators originate from two different series, only one could be used for further structural modifications. It could be de- monstrated, that the cyanostilbene derived so called “DG-series” underwent a presumable light-induced (E)/(Z)- isomerization instead of generating the desired radical. Potential probes from the so called “ST-series” derived ligands were synthesized, however, could unfortunately not be isolated from a mixture of several by-products. Another approach of generating a N-methylated, potential inverse agonist resulted in the synthesis of 98 (Figure 59), which failed to qualify as a potent candidate for the additional introduction of PA functions. In order to identify the off-target of compound DG172 52 an affinity probe was designed for further pull-down experiments. Based on the basis of the previously reported SAR, a novel ligand of the “DG-series” was successfully developed and was proven to not exhibit any affinity towards the PPARβ/δ ligand binding domain. In utilizing a broadly applied biotin-linker methodology, the final probe 112 (Figure 60) was generated via a traditional coupling approach. At the time of writing, the pull-down assays were still ongoing. The final project is a cooperation with the group of Prof. Dr. Matthias Lauth dealing with the optimization of a potential Hedgehog pathway modulator ISX-9 54 (Figure 61). Overall three ligand series were synthesized to deduce the underlying structure-activity relationship. One series included the systematical variation of the central core structure, which seems to be indispensable for the observed biological effect. In the other two se- ries, the substituents in 3- and 5-position were systematically altered, however, only one of the compounds was more active. Finally, the generation of affinity probes, e.g. 165 (Figure 62), lead to the discovery of three nucleus-based, potential protein targets after pull-down experiments. Moreover, a fluorescence probe 167 was synthesized in order to validate the pull-down results.