Aminopyridinecarboxamide-based inhaled IKK-2 inhibitors for asthma and COPD: Structure-activity relationship.

Installation of sites for metabolism in the lead compound PHA-767408 was the key focus of the IKK-2 inhaled program. This paper reports our efforts to identify a novel series of aminopyridinecarboxamide-based IKK-2 inhibitors, which display low nanomolar potency against IKK-2 with long duration of action (DOA), and metabolically labile to phase I and/or phase II metabolizing enzymes with potential capability for multiple routes of clearance. Several compounds have demonstrated their potential usefulness in the treatment of asthma and chronic obstructive pulmonary disease (COPD).

A benzothiophene inhibitor of mitogen-activated protein kinase-activated protein kinase 2 inhibits tumor necrosis factor alpha production and has oral anti-inflammatory efficacy in acute and chronic models of inflammation.

Activation of the p38 kinase pathway in immune cells leads to the transcriptional and translational regulation of proinflammatory cytokines. Mitogen-activated protein kinase-activated protein kinase 2 (MK2), a direct downstream substrate of p38 kinase, regulates lipopolysaccharide (LPS)-stimulated tumor necrosis factor alpha (TNFalpha) and interleukin-6 (IL-6) production through modulating the stability and translation of these mRNAs. Developing small-molecule inhibitors of MK2 may yield anti-inflammatory efficacy with a different safety profile relative to p38 kinase inhibitors. This article describes the pharmacologic properties of a benzothiophene MK2 inhibitor, PF-3644022 [(10R)-10-methyl-3-(6-methylpyridin-3-yl)-9,10,11,12-tetrahydro-8H-[1,4]diazepino[5',6':4,5]thieno[3,2-f]quinolin-8-one]. PF-3644022 is a potent freely reversible ATP-competitive compound that inhibits MK2 activity (K(i) = 3 nM) with good selectivity when profiled against 200 human kinases. In the human U937 monocytic cell line or peripheral blood mononuclear cells, PF-3644022 potently inhibits TNFalpha production with similar activity (IC(50) = 160 nM). PF-3644022 blocks TNFalpha and IL-6 production in LPS-stimulated human whole blood with IC(50) values of 1.6 and 10.3 microM, respectively. Inhibition of TNFalpha in U937 cells and blood correlates closely with inhibition of phospho-heat shock protein 27, a target biomarker of MK2 activity. PF-3644022 displays good pharmacokinetic parameters in rats and is orally efficacious in both the rat acute LPS-induced TNFalpha model and the chronic streptococcal cell wall-induced arthritis model. Dose-dependent inhibition of TNFalpha production in the acute model and inhibition of paw swelling in the chronic model is observed with ED(50) values of 6.9 and 20 mg/kg, respectively. PF-3644022 efficacy in the chronic inflammation model is strongly correlated with maintaining a C(min) higher than the EC(50) measured in the rat LPS-induced TNFalpha model.

Evaluation of the History of Safe Use of the Maize ZMM28 Protein.

The ZMM28 protein encoded by the zmm28 gene is endogenous to maize. DP202216 maize was genetically modified to increase and extend expression of the zmm28 gene relative to native zmm28 gene expression, resulting in plants with enhanced grain yield potential. Evaluation of the history of safe use (HOSU) is one component of the safety assessment framework for a newly expressed protein in a GM crop. The deduced amino acid sequence of the introduced ZMM28 protein in DP202216 maize is identical to the ZMM28 protein in nonmodified conventional maize. The ZMM28 protein has also been found in selected varieties of sweet corn kernels, and closely related proteins are found in other commonly consumed food crops. Concentrations of the ZMM28 protein in event DP202216 maize, conventional maize, and sweet corn are reported. This information supports, in part, the evaluation of HOSU, which can be leveraged in the safety assessment of the ZMM28 protein. Additional studies will be considered in the food and feed safety assessment of the DP202216 maize event.