Showing papers by "Anne-Marie Lambeir published in 2014"

Extended Structure–Activity Relationship and Pharmacokinetic Investigation of (4-Quinolinoyl)glycyl-2-cyanopyrrolidine Inhibitors of Fibroblast Activation Protein (FAP)

Abstract: Fibroblast activation protein (FAP) is a serine protease related to dipeptidyl peptidase IV (DPPIV). It has been convincingly linked to multiple disease states involving remodeling of the extracellular matrix. FAP inhibition is investigated as a therapeutic option for several of these diseases, with most attention so far devoted to oncology applications. We previously discovered the N-4-quinolinoyl-Gly-(2S)-cyanoPro scaffold as a possible entry to highly potent and selective FAP inhibitors. In the present study, we explore in detail the structure–activity relationship around this core scaffold. We report extensively optimized compounds that display low nanomolar inhibitory potency and high selectivity against the related dipeptidyl peptidases (DPPs) DPPIV, DPP9, DPPII, and prolyl oligopeptidase (PREP). The log D values, plasma stabilities, and microsomal stabilities of selected compounds were found to be highly satisfactory. Pharmacokinetic evaluation in mice of selected inhibitors demonstrated high oral ...

Importance of biofilm formation and dipeptidyl peptidase IV for the pathogenicity of clinical Porphyromonas gingivalis isolates

Abstract: The ability of Porphyromonas gingivalis to cause adult periodontitis is determined by its arsenal of virulence factors. Here, we investigated the importance of biofilm formation and bacterial dipeptidyl peptidase IV (DPPIV) for the pathogenicity of clinical P. gingivalis isolates. In our study, the isolates with biofilm-forming capacity also showed high DPPIV activity in vitro . Moreover, DPPIV activity increased in P. gingivalis biofilms compared to planktonic cells. In a murine subcutaneous abscess model, the biofilm-forming isolates with high DPPIV activity proved to be pathogenic, while the nonbiofilm formers with low DPPIV activity did not induce abscesses. The biofilm-forming ATCC 33277 strain with low DPPIV activity was not pathogenic in mice either. Our results suggest that biofilm formation and DPPIV activity contribute to the pathogenic potential of P. gingivalis . Furthermore, we show that biofilm formation may enhance P. gingivalis virulence through an increased DPPIV activity. Because of their importance for bacterial colonization and growth, biofilm formation and DPPIV activity could present interesting therapeutic targets to tackle periodontitis.

Selective inhibitors of fibroblast activation protein (FAP) with a xanthine scaffold

Abstract: Fibroblast activation protein (FAP) is a serine protease that is selectively expressed in many diseases involving activated stroma, including cancer, arthritis and hepatic and pulmonary fibrosis. FAP is closely related to dipeptidyl peptidase IV (DPPIV), of which many inhibitors are known and several are marketed as drugs. One of these is the xanthine derivative linagliptin. In a broad literature screen amongst reported DPPIV inhibitors, linagliptin was the only druglike compound identified that possessed significant FAP potency. Hence, this compound served as a starting point for a SAR study that aimed to identify structural determinants that selectively increase FAP-potency of linagliptin analogues. By investigating the influence of the substitution pattern on N1, N7 and C8 of the xanthine scaffold, we managed to decouple DPPIV and FAP potency and identified the first selective xanthine-based FAP inhibitors with low micromolar potency. Furthermore, these compounds are the only known FAP-inhibitors that do not rely on a warhead functionality to obtain potencies in this range.

Repositioning the Substrate Activity Screening (SAS) Approach as a Fragment-Based Method for Identification of Weak Binders

Abstract: Fragment-based drug discovery (FBDD) has evolved into an established approach for "hit" identification. Typically, most applications of FBDD depend on specialised cost- and time-intensive biophysical techniques. The substrate activity screening (SAS) approach has been proposed as a relatively cheap and straightforward alternative for identification of fragments for enzyme inhibitors. We have investigated SAS for the discovery of inhibitors of oncology target urokinase (uPA). Although our results support the key hypotheses of SAS, we also encountered a number of unreported limitations. In response, we propose an efficient modified methodology: "MSAS" (modified substrate activity screening). MSAS circumvents the limitations of SAS and broadens its scope by providing additional fragments and more coherent SAR data. As well as presenting and validating MSAS, this study expands existing SAR knowledge for the S1 pocket of uPA and reports new reversible and irreversible uPA inhibitor scaffolds.