Fragment-gebaseerde methoden voor de ontwikkeling van inhibitoren van urokinase plasminogeen activator (uPA)
10 mei 2016
UAntwerpen, Campus Middelheim, Gebouw A, A.143 - Middelheimlaan 1 - 2020 Antwerpen (Wilrijk)
15 - 19 uur
Pieter Van der Veken
Doctoraatsverdediging Rafaela Gladysz - Departement Farmaceutische Wetenschappen
Fragment-based approaches to inhibitors of urokinase plasminogen activator (uPA)
Fragment-Based Drug Discovery (FBDD) has evolved into an established methodology for ‘hit’ identification. Nonetheless, the approach still faces a number of fundamental challenges. One of these relates to the need for specialized cost- and time-intensive biophysical techniques to detect and study weak binding fragments. The Substrate Activity Screening (SAS) approach has been proposed as a relatively cheap and straightforward alternative for the identification of fragments for enzyme inhibitors. In spite of some promising results, it has so far only seen limited investigation mainly by the group of Jonathan Ellman.
In this study, we applied SAS to the discovery of inhibitors of oncology target urokinase (uPA). During our investigation, a number of unreported limitations of the SAS-based approach were uncovered. In response, we developed a modified, more efficient alternative method: the MSAS approach. MSAS not only circumvents the limitations of SAS but also broadens its scope by providing additional fragments and more coherent SAR data. As a result, we identified a number of interesting S1-binding fragments for uPA. The latter were used to prepare scaffold-based inhibitors following the Groebke-Blackburn-Bienaymé (GBB) three-component reaction protocol. Optimization of the initial hit compound provided reversible non-peptidic uPA inhibitors of nanomolar potency and high selectivity against the related trypsin-like serine proteases.
Additionally, in the course of this study a number of inhibitors carrying a warhead function were prepared, and served as a proof-of-concept for the SAS-based identification of uPA inhibitors.
In the last part of this PhD research the 'on-target' approach to inhibitors of uPA has been explored, yielding a general experimental protocol as well as an early proof-of-concept for the on-target version of the GBB reaction.
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