Discovery of novel N-phenylphenoxyacetamide derivatives as EthR inhibitors and ethionamide boosters by combining high-throughput screening and synthesis.
In this paper, we describe the screening of a 14640-compound library using a novel whole mycobacteria phenotypic assay to discover inhibitors of EthR, a transcriptional repressor implicated in the innate resistance of  Mycobacterium tuberculosis  to the second-line antituberculosis drug ethionamide. From this screening a new chemical family of EthR inhibitors bearing an N-phenylphenoxyacetamide motif was identified. The X-ray structure of the most potent compound crystallized with EthR inspired the synthesis of a 960-member focused library. These compounds were tested in vitro using a rapid thermal shift assay on EthR to accelerate the optimization. The best compounds were synthesized on a larger scale and confirmed as potent ethionamide boosters on  M. tuberculosis -infected macrophages. Finally, the cocrystallization of the best optimized analogue with EthR revealed an unexpected reorientation of the ligand in the binding pocket.
Université Lille Nord de France, F-59000 Lille, France.
Marion
M
Flipo
Nicolas
N
Willand
Nathalie
N
Lecat-Guillet
Candide
C
Hounsou
Matthieu
M
Desroses
Florence
F
Leroux
Zoé
Z
Lens
Vincent
V
Villeret
Alexandre
A
Wohlkönig
René
R
Wintjens
Thierry
T
Christophe
Hee
H
Kyoung Jeon
Camille
C
Locht
Priscille
P
Brodin
Alain R
AR
Baulard
Benoit
B
Déprez
D000081:Acetamides / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology*; D000818:Animals; D000995:Antitubercular Agents / Q000494:pharmacology*; D002460:Cell Line; D060326:Chemistry Techniques, Synthetic; D055808:Drug Discovery; D004357:Drug Synergism; D005000:Ethionamide / Q000494:pharmacology*; D057166:High-Throughput Screening Assays; D008024:Ligands; D008264:Macrophages / Q000187:drug effects / Q000382:microbiology; D051379:Mice; D008958:Models, Molecular; D009169:Mycobacterium tuberculosis / Q000187:drug effects; D011487:Protein Conformation; D012097:Repressor Proteins / Q000037:antagonists & inhibitors* / Q000737:chemistry
D000081:Acetamides; D000995:Antitubercular Agents; C481661:EthR protein, Mycobacterium tuberculosis; D008024:Ligands; D012097:Repressor Proteins; D005000:Ethionamide