301326-22-7

CH-221391 (CAS 301326-22-7) is an arylhydrocarbon (AhR) receptor antagonist, IC50=30 nM.1 Blocks endogenous AhR agonist-induced differentiation of Th17 cells.2?? Promotes expansion of human hematopoietic stem cells.3 Mitigates cytokine-mediated inflammatory signaling in human fibroblast-like synoviocytes.4 An important tool for probing the involvement of AhR in the toxicity of various environmental toxins such as TCDD and other dioxins.5

ChEBI: 2-methyl-N-[2-methyl-4-(2-methylphenyl)azophenyl]-3-pyrazolecarboxamide is an aromatic amide.

CH-223191 is a potent and specific aryl hydrocarbon receptor (AhR) antagonist. It inhibited TCDD-mediated nuclear translocation and DNA binding of AhR, and inhibited TCDD-induced luciferase activity with an IC50 of 30nM. Unlike some other AhR antagonists which display agonist activity at high concentrations, CH-223191 did not stimulate AhR-dependent transcription even at 100 micromolar. It is also specific for AhR, displaying no affinity for the estrogen receptor, as some other antagonists do.

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1) Kim et al. (2006), Novel compound 2-methyl-2H-pyrazole-3-carboxylic acid (2-methyl-4-o-tolylazo-phenyl)amide (CH-223191) prevents 2,3,7,8-TCDD-induced toxicity by antagonizing the aryl hydrocarbon receptor; Mol. Pharmacol., 69 1871 2) Veldhoen et al. (2009), Natural agonists for aryl hydrocarbon receptor in culture medium are essential for optimal differentiation of Th17 T cells; J. Exp. Med., 206 43 3) Carlin et al. (2013), T-cell potential of human adult and cord blood hemopoietic stem cells expanded with the use of aryl hydrocarbon receptor antagonists; Cytotherapy, 15 224 4) Lahoti et al. (2013), Aryl hydrocarbon receptor antagonism mitigates cytokine-mediated inflammatory signaling in primary human fibroblast-like synoviocytes; Ann. Rheum. Dis, 72 1708 5) Petroff et al. (2011), The aryl hydrocarbon receptor agonist 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) alters early embryonic development in a rat IVF exposure model; Reprod. Toxicol., 32 286