Imidazo[2,1‑b]benzothiazol Derivatives as Potential Allosteric Inhibitors of the Glucocorticoid Receptor

• Published in: ACS medicinal chemistry letters Vol. 9; no. 4; pp. 339 - 344
• Main Authors: Christodoulou, Michael S, Dapiaggi, Federico, Ghiringhelli, Francesca, Pieraccini, Stefano, Sironi, Maurizio, Lucafò, Marianna, Curci, Debora, Decorti, Giuliana, Stocco, Gabriele, Chirumamilla, Chandra Sekhar, Vanden Berghe, Wim, Balaguer, Patrick, Michel, Benoît Y, Burger, Alain, Beccalli, Egle M, Passarella, Daniele, Martinet, Nadine
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 12-04-2018
• Subjects: Cancer; Human health and pathology; Letter; Life Sciences; GCR allosteric inhibition; anti-inflammatory GCR like activity; imidazo[2,1-b]benzoimidazole; reduced GILZ expression; Imidazo[2,1-b]benzothiazole
• ISSN: 1948-5875; 1948-5875
• DOI: 10.1021/acsmedchemlett.7b00527

Glucocorticoid receptor (GCR) transactivation reporter gene assays were used as an initial high-throughput screening on a diversified library of 1200 compounds for their evaluation as GCR antagonists. A class of imidazo­[2,1-b]­benzothiazole and imidazo­[2,1-b]­benzoimidazole derivatives were identified for their ability to modulate GCR transactivation and anti-inflammatory transrepression effects utilizing GCR and NF-κB specific reporter gene assays. Modeling studies on the crystallographic structure of the GCR ligand binding domain provided three new analogues bearing the tetrahydroimidazo­[2,1-b]­benzothiazole scaffold able to antagonize the GCR in the presence of dexamethasone (DEX) and also defined their putative binding into the GCR structure. Both mRNA level measures of GCR itself and its target gene GILZ, on cells treated with the new analogues, showed a GCR transactivation inhibition, thus suggesting a potential allosteric inhibition of the GCR.