- Modified Peptide Inhibitors of the Keap1–Nrf2 Protein–Protein Interaction Incorporating Unnatural Amino Acids
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Noncovalent inhibitors of the Keap1–Nrf2 protein–protein interaction (PPI) have therapeutic potential in a range of disease states including neurodegenerative diseases (Parkinson's and Alzheimer's diseases), chronic obstructive pulmonary disease and various inflammatory conditions. By stalling Keap1-mediated ubiquitination of Nrf2, such compounds can enhance Nrf2 transcriptional activity and activate the expression of a range of genes with antioxidant response elements in their promoter regions. Keap1 inhibitors based on peptide and small-molecule templates have been identified. In this paper we develop the structure–activity relationships of the peptide series and identify a group of ligands incorporating unnatural amino acids that demonstrate improved binding affinity in fluorescence polarisation, differential scanning fluorimetry and isothermal titration calorimetry assays. These modified peptides have the potential for further development into peptidomimetic chemical probes to explore the role of Nrf2 in disease and as potential lead structures for drug development.
- Georgakopoulos, Nikolaos D.,Talapatra, Sandeep K.,Gatliff, Jemma,Kozielski, Frank,Wells, Geoff
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- Triphenylbutanamines: Kinesin spindle protein inhibitors with in vivo antitumor activity
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The human mitotic kinesin Eg5 represents a novel mitotic spindle target for cancer chemotherapy. We previously identified S-trityl-l-cysteine (STLC) and related analogues as selective potent inhibitors of Eg5. We herein report on the development of a series of 4,4,4-triphenylbutan-1-amine inhibitors derived from the STLC scaffold. This new generation systematically improves on potency: the most potent C-trityl analogues exhibit Kiapp ≥ 10 nM and GI50 ≈ 50 nM, comparable to results from the phase II clinical benchmark ispinesib. Crystallographic studies reveal that they adopt the same overall binding configuration as S-trityl analogues at an allosteric site formed by loop L5 of Eg5. Evaluation of their druglike properties reveals favorable profiles for future development and, in the clinical candidate ispinesib, moderate hERG and CYP inhibition. One triphenylbutanamine analogue and ispinesib possess very good bioavailability (51% and 45%, respectively), with the former showing in vivo antitumor growth activity in nude mice xenograft studies.
- Wang, Fang,Good, James A. D.,Rath, Oliver,Kaan, Hung Yi Kristal,Sutcliffe, Oliver B.,MacKay, Simon P.,Kozielski, Frank
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p. 1511 - 1525
(2012/04/10)
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