How does binding of imidazole-based inhibitors to heme oxygenase-1 influence their conformation? Insights combining crystal structures and molecular modelling.

Heme oxygenase-1 (HO-1) inhibition is associated with antitumor activity. Imidazole-based analogues show effective and selective inhibitory potency of HO-1. In this work, five single-crystal structures of four imidazole-based compounds are presented, with an in-depth structural analysis.

Thiosemicarbazide, a fragment with promising indolamine-2,3-dioxygenase (IDO) inhibition properties.

With the aim to explore the interest of the thiosemicarbazide scaffold for the inhibition of the indoleamine 2,3-dioxygenase (IDO), a promising therapeutic target for anticancer immunotherapy, a series of 32 phenylthiosemicarbazide derivatives was prepared and their IDO inhibition evaluated. Our study demonstrated that among these derivatives, compound 14 characterized with a 4-cyanophenyl group on the thiosemicarbazide was the more potent IDO inhibitor in this series being endowed with an IC50 of 1.2 μM.

Synthesis, crystal structures and electronic properties of isomers of chloro-pyridinylvinyl-1H-indoles.

Three isomers of chloro-3-(2-pyridin-3-ylvinyl)-1H-indole were synthesized and tested as inhibitors of human tryptophan 2,3-dioxygenase (hTDO). The crystal structures of two of them were solved by X-ray diffraction. The solubility of the molecules also was determined experimentally.

Synthesis and inhibition study of monoamine oxidase, indoleamine 2,3-dioxygenase and tryptophan 2,3-dioxygenase by 3,8-substituted 5H-indeno[1,2-c]pyridazin-5-one derivatives.

Previous studies on 5H-indeno[1,2-c]pyridazin-5-one derivatives as inhibitors of MAO-B revealed that it was possible to increase the MAO-B inhibitory potency of 5H-indeno[1,2-c]pyridazin-5-ones by substituting the central heterocycle in the 3-position or C-8 with lipophilic groups which occupy the substrate cavity or the entrance of the binding site, respectively. Here, four new 5H-indeno[1,2-c]pyridazin-5-one derivatives containing lipophilic groups at both positions were synthesized and their inhibitory potency against human monoamine oxidase A and B were evaluated. Selectivity of these compounds against IDO and TDO, two enzymes sharing substrate similarity with MAO and involved in the serotonergic and kynurenine pathways was also studied.

Tryptophan 2,3-dioxygenase (TDO) inhibitors. 3-(2-(pyridyl)ethenyl)indoles as potential anticancer immunomodulators.

Tryptophan catabolism mediated by indoleamine 2,3-dioxygenase (IDO) is an important mechanism of peripheral immune tolerance contributing to tumoral immune resistance. IDO inhibition is thus an active area of research in drug development. Recently, our group has shown that tryptophan 2,3-dioxygenase (TDO), an unrelated hepatic enzyme also catalyzing the first step of tryptophan degradation, is also expressed in many tumors and that this expression prevents tumor rejection by locally depleting tryptophan.