Inhibitors of Tumor Progression Loci-2 (Tpl2) Kinase and Tumor Necrosis Factor α (TNF-α) Production: Selectivity and in Vivo Antiinflammatory Activity of Novel 8-Substituted-4-anilino-6-aminoquinoline-3-carbonitriles

Tumor progression loci-2 (Tpl2) (Cot/MAP3K8) is a serine/threonine kinase in the MAP3K family directly
upstream of MEK. Recent studies using Tpl2 knockout mice have indicated an important role for Tpl2 in
the lipopolysaccharide (LPS) induced production of tumor necrosis factor α (TNF-α) and other proinflammatory cytokines involved in diseases such as rheumatoid arthritis. Initial 4-anilino-6-aminoquinoline-3-carbonitrile leads showed poor selectivity for Tpl2 over epidermal growth factor receptor (EGFR) kinase.
Using molecular modeling and crystallographic data of the EGFR kinase domain with and without an EGFR
kinase-specific 4-anilinoquinazoline inhibitor (erlotinib, Tarceva), we hypothesized that we could diminish
the inhibition of EGFR kinase by substitution at the C-8 position of our 4-anilino-6-aminoquinoline-3-carbonitrile leads. The 8-substituted-4-anilino-6-aminoquinoline-3-carbonitriles were prepared from the
appropriate 2-substituted 4-nitroanilines. Modifications to the C-6 and C-8 positions led to the identification
of compounds with increased inhibition of TNF-α release from LPS-stimulated rat and human blood, and
these analogues were also highly selective for Tpl2 kinase over EGFR kinase. Further structure−activity
based modifications led to the identification of 8-bromo-4-(3-chloro-4-fluorophenylamino)-6-[(1-methyl-1H-imidazol-4-yl)methylamino]quinoline-3-carbonitrile, which demonstrated in vitro as well as in vivo
efficacy in inhibition of LPS-induced TNF-α production.