Collaborative Virtual Screening Identifies a 2-Aryl-4-aminoquinazoline Series with Efficacy in an In Vivo Model of Trypanosoma cruzi Infection.

Probing multiple proprietary pharmaceutical libraries in parallel via virtual screening allowed rapid expansion of the structure-activity relationship (SAR) around hit compounds with moderate efficacy against Trypanosoma cruzi, the causative agent of Chagas Disease. A potency-improving scaffold hop, followed by elaboration of the SAR via design guided by the output of the phenotypic virtual screening efforts, identified two promising hit compounds 54 and 85, which were profiled further in pharmacokinetic studies and in an in vivo model of T. cruzi infection. Compound 85 demonstrated clear reduction of parasitemia in the in vivo setting, confirming the interest in this series of 2-(pyridin-2-yl)quinazolines as potential anti-trypanosome treatments.

Identification of Thiazoyl Guanidine Derivatives as Novel Antifungal Agents Inhibiting Ergosterol Biosynthesis for Treatment of Invasive Fungal Infections.

Invasive fungal infections (IFIs) are fatal infections, but treatment options are limited. The clinical efficacies of existing drugs are unsatisfactory because of side effects, drug-drug interaction, unfavorable pharmacokinetic profiles, and emerging drug-resistant fungi. Therefore, the development of antifungal drugs with a new mechanism is an urgent issue. Herein, we report novel aryl guanidine antifungal agents, which inhibit a novel target enzyme in the ergosterol biosynthesis pathway. Structure-activity relationship development and property optimization by reducing lipophilicity led to the discovery of 6h, which showed potent antifungal activity against Aspergillus fumigatus in the presence of serum, improved metabolic stability, and PK properties. In the murine systemic A. fumigatus infection model, 6h exhibited antifungal efficacy equivalent to voriconazole (1e). Furthermore, owing to the inhibition of a novel target in the ergosterol biosynthesis pathway, 6h showed antifungal activity against azole-resistant A. fumigatus.

Collaborative virtual screening to elaborate an imidazo[1,2-a]pyridine hit series for visceral leishmaniasis.

An innovative pre-competitive virtual screening collaboration was engaged to validate and subsequently explore an imidazo[1,2-a]pyridine screening hit for visceral leishmaniasis. In silico probing of five proprietary pharmaceutical company libraries enabled rapid expansion of the hit chemotype, alleviating initial concerns about the core chemical structure while simultaneously improving antiparasitic activity and selectivity index relative to the background cell line. Subsequent hit optimization informed by the structure-activity relationship enabled by this virtual screening allowed thorough investigation of the pharmacophore, opening avenues for further improvement and optimization of the chemical series.

International exchange activities with East Asian countries through mammography.

The Japanese NPO Central Committee on Quality Control of Mammographic Screening has initiated international exchange activities regarding quality control of mammographic screening with the concerned organizations in East Asian countries with the objective of contributing to reducing breast cancer mortality in the region. This paper describes the status of the international exchanges that are being carried out in various East Asian countries in relation to mammography and also discusses future aspects.

A selective peroxisome proliferator-activated receptor gamma modulator with distinct fat cell regulation properties.

Adipogenesis is an important process for the improvement of insulin resistance by peroxisome proliferator-activated receptor (PPAR) gamma agonists, such as rosiglitazone and pioglitazone. FK614 [3-(2,4-dichlorobenzyl)-2-methyl-N-(pentylsulfonyl)-3-Hbenzimidazole-5-carboxamide] is a structurally novel class of PPARgamma agonist that improves insulin sensitivity in animal models of type 2 diabetes. Herein, we characterize FK614, a selective PPARgamma modulator (SPPARM) with differential properties affecting the regulation of fat cell function. FK614 behaves as a partial agonist in inducing the interaction of PPARgamma with both transcriptional coactivators, cAMP response element-binding protein-binding protein and steroid receptor coactivator-1, but as a full agonist with both PPAR-binding protein and PPAR-interacting protein, which are required for PPARgamma-mediated adipogenesis. In the differentiating 3T3-L1 adipocytes, the levels of adipose fatty acid-binding protein (aP2) mRNA expression and triglyceride accumulation induced by FK614 were as efficacious as those of rosiglitazone and pioglitazone. In contrast, the effect of FK614 on aP2 gene expression in mature adipocytes was less than that of the other PPARgamma agonists. Furthermore, the long-term treatment of mature adipocytes with rosiglitazone and pioglitazone reduced the expression of phosphodiesterase 3B, the down-regulation of which has an important role in the development of insulin resistance; however, FK614 had no such effect in mature adipocytes. Thus, FK614 behaves as an SPPARM with differential effects on the activation of PPARgamma at each stage of adipocyte differentiation. The stage-dependent selectivity of FK614 may contribute to its enhanced insulin sensitization in differentiating adipocytes and to reduced insulin resistance at the stage of adipocyte hypertrophy.

FK614, a novel peroxisome proliferator-activated receptor gamma modulator, induces differential transactivation through a unique ligand-specific interaction with transcriptional coactivators.

Peroxisome proliferator-activated receptor gamma (PPARgamma) is a ligand-dependent transcriptional factor implicated in regulating adipogenesis, glucose homeostasis, and in mediating the action of the insulin sensitizing anti-diabetic thiazolidinedione (TZD) compounds. [3-(2,4-Dichlorobenzyl)-2-methyl-N-(pentylsulfonyl)-3-H-benzimidazole-5-carboxamide] (FK614) is a structurally novel PPARgamma agonist that demonstrates potent anti-diabetic activity in vivo. Herein, we describe that FK614 is a selective PPARgamma ligand with specific transactivation properties that are dependent upon the context of coactivators. FK614 dissociates the corepressors NCoR (nuclear receptor corepressor) and SMRT (silencing mediator of retinoid and thyroid hormone receptors) from PPARgamma as effectively as rosiglitazone and pioglitazone, but can also differentially induce a ligand specific interaction of PPARgamma with coactivators. The amount of CBP (CREB-binding protein) and SRC-1 (steroid receptor coactivator-1) recruited by FK614 was less than that induced by rosiglitazone and pioglitazone, but FK614 caused similar PGC-1alpha (PPARgamma coactivator-1alpha) recruitment as these compounds. As a consequence of these ligand-specific differences in the strength of ligand-type specific interactions of PPARgamma and coactivators, FK614 functions as a partial or full agonist for transcriptional activation depending upon the amount of specific coactivators in cells following overexpression. In conclusion, FK614 is a novel, non-TZD type, and selective PPARgamma modulator whose pharmacological properties are distinct from rosiglitazone and pioglitazone.