| 1. |
|
|
| 2. |
- Ehrenberg, Angelica, et al.
(författare)
-
Accounting for strain variations and resistance mutations in the characterization of hepatitis C NS3 protease inhibitors
- 2014
-
Ingår i: Journal of enzyme inhibition and medicinal chemistry (Print). - : Informa UK Limited. - 1475-6366 .- 1475-6374. ; 29:6, s. 868-876
-
Tidskriftsartikel (refereegranskat)abstract
- Context: Natural strain variation and rapid resistance development makes development of broad spectrum hepatitis C virus (HCV) drugs very challenging and evaluation of inhibitor selectivity and resistance must account for differences in the catalytic properties of enzyme variants.Objective: To understand how to study selectivity and relationships between efficacy and genotype or resistant mutants for NS3 protease inhibitors.Materials and methods: The catalytic properties of NS3 protease from genotypes 1a, 1b and 3a, and their sensitivities to four structurally and mechanistically different NS3 protease inhibitors have been analysed under different experimental conditions.Results: The optimisation of buffer conditions for each protease variant enabled the comparison of their catalytic properties and sensitivities to the inhibitors. All inhibitors were most effective against genotype 1a protease, with VX-950 having the broadest selectivity.Discussion and conclusion: A new strategy for evaluation of inhibitors relevant for the discovery of broad spectrum HCV drugs was established.
|
|
| 3. |
- Ehrenberg, Angelica, 1980-
(författare)
-
Novel Procedures for Identification and Characterization of Viral Proteases Inhibitors
- 2014
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Viral proteases are often considered to be attractive drug targets because of their crucial function in the viral replication machinery. In order to increase our knowledge of these important targets and to contribute to the discovery and development of new antiviral drugs, the proteases from hepatitis C virus (HCV) and human cytomegalovirus (HCMV) have been produced and their interactions with inhibitors and fragments have been characterized, using enzyme inhibition and SPR biosensor based interaction assay.The structure activity relationships and the resistance profiles of a series of HCV NS3 protease inhibitors based on either P2 proline or phenylglycine residues were analyzed using wild type genotype 1a and the major resistant variants A156T and D168V. The observed susceptibility to substitutions associated with these resistance variants was concluded to depend on the P2 and the P1 residue, and not only on the P2 residue as previously had been suggested. In order to be able to evaluate how the potency of inhibitors is affected by genetic variation, their effect was evaluated on wild type NS3 from genotype 1a, 1b and 3a as well as on the resistant variant R155K from genotype 1a. To enable a comparison of the inhibitory effect on the enzyme variants, the compounds were analyzed under conditions optimized for each variant. VX-950 was found to be the least susceptible compound to resistance and genetic variation. A more detailed analysis showed that the kinetic and mechanistic features of the inhibitors were significantly different for the different genotypes. The reversible non covalent macrocyclic inhibitor ITMN 191 was revealed to have favorable kinetics for all three genotypes. This is an advantage for the design of broad spectrum drugs.A fragment based procedure for identifying and validating novel scaffolds for inhibitors of HCMV protease was established. It identified fragments that may serve as starting points for the discovery of effective inhibitors against this challenging target. The procedures developed for the evaluation and identification of novel HCV NS3 and HCMV protease inhibitors have contributed to a deeper understanding of protease-inhibitor interactions that is expected to have an impact on the design of novel antiviral drugs.
|
|
| 4. |
- Gising, Johan, 1981-, et al.
(författare)
-
Achiral Pyrazinone-Based Inhibitors of the Hepatitis C Virus NS3 Protease and Drug-Resistant Variants with Elongated Substituents Directed Toward the S2 Pocket
- 2014
-
Ingår i: Journal of Medicinal Chemistry. - : American Chemical Society (ACS). - 0022-2623 .- 1520-4804. ; 57:5, s. 1790-1801
-
Tidskriftsartikel (refereegranskat)abstract
- Herein we describe the design, synthesis, inhibitory potency, and pharmacokinetic properties of a novel class of achiral peptidomimetic HCV NS3 protease inhibitors. The compounds are based on a dipeptidomimetic pyrazinone glycine P3P2 building block in combination with an aromatic acyl sulfonamide in the P1P1′ position. Structure–activity relationship data and molecular modeling support occupancy of the S2 pocket from elongated R6 substituents on the 2(1H)-pyrazinone core and several inhibitors with improved inhibitory potency down to Ki = 0.11 μM were identified. A major goal with the design was to produce inhibitors structurally dissimilar to the di- and tripeptide-based HCV protease inhibitors in advanced stages of development for which cross-resistance might be an issue. Therefore, the retained and improved inhibitory potency against the drug-resistant variants A156T, D168V, and R155K further strengthen the potential of this class of inhibitors. A number of the inhibitors were tested in in vitro preclinical profiling assays to evaluate their apparent pharmacokinetic properties. The various R6 substituents were found to have a major influence on solubility, metabolic stability, and cell permeability.
|
|
| 5. |
|
|
| 6. |
- Lampa, Anna, et al.
(författare)
-
Improved P2 phenylglycine-based hepatitis C virus NS3 protease inhibitors with alkenylic prime-side substituents
- 2010
-
Ingår i: Bioorganic & Medicinal Chemistry. - : Elsevier BV. - 0968-0896 .- 1464-3391. ; 18:14, s. 5413-5424
-
Tidskriftsartikel (refereegranskat)abstract
- Phenylglycine has proved to be a useful P2 residue in HCV NS3 protease inhibitors. A novel pi-pi-interaction between the phenylglycine and the catalytic H57 residue of the protease is postulated. We hypothesized that the introduction of a vinyl on the phenylglycine might strengthen this pi-pi-interaction. Thus, herein is presented the synthesis and inhibitory potency of a series of acyclic vinylated phenylglycine-based HCV NS3 protease inhibitors. Surprisingly, inhibitors based on both D- and L-phenylglycine were found to be effective inhibitors, with a slight preference for the d-epimers. Furthermore, prime-side alkenylic extension of the C-terminal acylsulfonamide group gave significantly improved inhibitors with potencies in the nanomolar range (approximately 35 nM), potencies which were retained on mutant variants of the protease.
|
|
| 7. |
|
|
| 8. |
- Lampa, Anna, et al.
(författare)
-
P2-P1 ' macrocyclization of P2 phenylglycine based HCV NS3 protease inhibitors using ring-closing metathesis
- 2011
-
Ingår i: Bioorganic & Medicinal Chemistry. - : Elsevier BV. - 0968-0896 .- 1464-3391. ; 19:16, s. 4917-4927
-
Tidskriftsartikel (refereegranskat)abstract
- Macrocyclization is a commonly used strategy to preorganize HCV NS3 protease inhibitors in their bioactive conformation. Moreover, macrocyclization generally leads to greater stability and improved pharmacokinetic properties. In HCV NS3 protease inhibitors, it has been shown to be beneficial to include a vinylated phenylglycine in the P2 position in combination with alkenylic P1' substituents. A series of 14-, 15- and 16-membered macrocyclic HCV NS3 protease inhibitors with the linker connecting the P2 phenylglycine and the alkenylic P1' were synthesized by ring-closing metathesis, using both microwave and conventional heating. Besides formation of the expected macrocycles in cis and trans configuration as major products, both ring-contracted and double-bond migrated isomers were obtained, in particular during formation of the smaller rings (14- and 15-membered rings). All inhibitors had K(i)-values in the nanomolar range, but only one inhibitor type was improved by rigidification. The loss in inhibitory effect can be attributed to a disruption of the beneficial pi-pi interaction between the P2 fragment and H57, which proved to be especially deleterious for the D-phenylglycine epimers.
|
|
| 9. |
- Lampa, Anna, et al.
(författare)
-
Vinylated linear P2 pyrimidinyloxyphenylglycine based inhibitors of the HCV NS3/4A protease and corresponding macrocycles
- 2014
-
Ingår i: Bioorganic & Medicinal Chemistry. - : Elsevier BV. - 0968-0896 .- 1464-3391. ; 22:23, s. 6595-6615
-
Tidskriftsartikel (refereegranskat)abstract
- With three recent market approvals and several inhibitors in advanced stages of development, the hepatitis C virus (HCV) NS3/4A protease represents a successful target for antiviral therapy against hepatitis C. As a consequence of dealing with viral diseases in general, there are concerns related to the emergence of drug resistant strains which calls for development of inhibitors with an alternative binding-mode than the existing highly optimized ones. We have previously reported on the use of phenylglycine as an alternative P2 residue in HCV NS3/4A protease inhibitors. Herein, we present the synthesis, structure-activity relationships and in vitro pharmacokinetic characterization of a diverse series of linear and macrocyclic P2 pyrimidinyloxyphenylglycine based inhibitors. With access to vinyl substituents in P3, P2 and P1' positions an initial probing of macrocyclization between different positions, using ring-closing metathesis (RCM) could be performed, after addressing some synthetic challenges. Biochemical results from the wild type enzyme and drug resistant variants (e.g., R155 K) indicate that P3-P1' macrocyclization, leaving the P2 substituent in a flexible mode, is a promising approach. Additionally, the study demonstrates that phenylglycine based inhibitors benefit from p-phenylpyrimidinyloxy and m-vinyl groups as well as from the combination with an aromatic P1 motif with alkenylic P1' elongations. In fact, linear P2-P1' spanning intermediate compounds based on these fragments were found to display promising inhibitory potencies and drug like properties.
|
|
| 10. |
|
|
| 11. |
|
|
| 12. |
- Örtqvist, Pernilla, et al.
(författare)
-
Discovery of Achiral Inhibitors of the Hepatitis C Virus NS3 Protease based on 2(1H)-pyrazinones
- 2010
-
Ingår i: Bioorganic & Medicinal Chemistry. - : Elsevier BV. - 0968-0896 .- 1464-3391. ; 18:17, s. 6512-6525
-
Tidskriftsartikel (refereegranskat)abstract
- Herein, the design, synthesis and inhibitory potency of a series of novel hepatitis C virus (HCV) NS3 protease inhibitors are presented. These inhibitors are based on a 2(1H)-pyrazinone P3 scaffold in combination with either a P2 phenylglycine or a glycine, and they were evaluated on the wild type as well as on two resistant variants of the enzyme, A156T and D168V. Molecular modelling suggested that the aromatic side-chain of the P2 phenylglycine occupies the same space as the substituent in position 6 on the pyrazinone core. The versatile synthetic route applied for the pyrazinone synthesis made a switch between the two positions easily feasible, resulting in phenyl- or benzyl substituted pyrazinones and leaving glycine as the P2 residue. Of several P1-P1′ residues evaluated, an aromatic P1-P1′ scaffold was found superior in combination with the new P3-P2 building block. As a result, an entirely new type of achiral and rigidified inhibitors was discovered, with the best of the novel inhibitors having fourfold improved potency compared to the corresponding tripeptide lead. We consider these achiral inhibitors highly suitable as starting points for further optimization.
|
|
| 13. |
- Örtqvist, Pernilla, et al.
(författare)
-
Structure-activity relationships of HCV NS3 protease inhibitors evaluated on the drug-resistant variants A156T and D168V
- 2010
-
Ingår i: Antiviral Therapy. - 1359-6535 .- 2040-2058. ; 15:6, s. 841-852
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: HCV infections are a serious threat to public health. An important drug target is the NS3 protease, for which several inhibitors are in clinical trials. Because of the high mutation rate of the virus, resistance against any HCV-specific drug is likely to become a substantial problem. Structure-activity data for the major resistant variants are therefore needed to guide future designs of protease inhibitors. METHODS: The inhibitory potency of tripeptide NS3 protease inhibitors, with either a P2 proline or phenylglycine, in combination with different P3 and P1-P1' groups, was assessed in enzyme activity assays using the full-length NS3 protein with known resistance-conferring substitutions A156T or D168V. The results obtained from these variants were compared with the inhibition of the wild-type enzyme. Molecular modelling was used to rationalize the biochemical results. RESULTS: Inhibitors combining the P2 proline and P1 (1R,2S)-1-amino-2-vinylcyclopropyl-carboxylic acid (vinylACCA) lost much of their potency on the resistant variants. Exchange of the P2 proline for phenylglycine yielded inhibitors that were equipotent on the wild-type and on the A156T and D168V variants. The same result was obtained from the combination of either the P2 residue with a norvaline or an aromatic scaffold in the P1 position. CONCLUSIONS: The combination of a substituted P2 proline and P1 vinylACCA appears to be the main problem behind the observed resistance. Molecular modelling suggests an enforced change in binding conformation for the P2 proline-based inhibitors, whereas the phenylglycine-based inhibitors retained their wild-type binding conformation in the substituted forms of the enzyme.
|
|
| 14. |
|
|
