RESUMO
The mitogen-activated protein kinase p38α pathway has been an attractive target for the treatment of inflammatory conditions such as rheumatoid arthritis. While a number of p38α inhibitors have been taken to the clinic, they have been limited by their efficacy and toxicological profile. A lead identification program was initiated to selectively target prevention of activation (PoA) of mitogen-activated protein kinase-activated protein kinaseâ 2 (MK2) rather than mitogen- and stress-activated protein kinaseâ 1 (MSK1), both immediate downstream substrates of p38α, to improve the efficacy/safety profile over direct p38α inhibition. Starting with a series of pyrazole amide PoA MK2 inhibitor leads, and guided by structural chemistry and rational design, a highly selective imidazole 9 (2-(3'-(2-amino-2-oxoethyl)-[1,1'-biphenyl]-3-yl)-N-(5-(N,N-dimethylsulfamoyl)-2-methylphenyl)-1-propyl-1H-imidazole-5-carboxamide) and the orally bioavailable imidazole 18 (3-methyl-N-(2-methyl-5-sulfamoylphenyl)-2-(o-tolyl)imidazole-4-carboxamide) were discovered. The PoA concept was further evaluated by protein immunoblotting, which showed that the optimized PoA MK2 compounds, despite their biochemical selectivity against MSK1 phosphorylation, behaved similarly to p38 inhibitors in cellular signaling. This study highlights the importance of selective tool compounds in untangling complex signaling pathways, and although 9 and 18 were not differentiated from p38α inhibitors in a cellular context, they are still useful tools for further research directed to understand the role of MK2 in the p38α signaling pathway.
Assuntos
Anti-Inflamatórios/síntese química , Ativação Enzimática/efeitos dos fármacos , Imidazóis/síntese química , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Proteína Quinase 14 Ativada por Mitógeno/antagonistas & inibidores , Inibidores de Proteínas Quinases/síntese química , Proteínas Serina-Treonina Quinases/metabolismo , Pirazóis/química , Anti-Inflamatórios/farmacologia , Células Cultivadas , Humanos , Imidazóis/farmacologia , Terapia de Alvo Molecular , Inibidores de Proteínas Quinases/farmacologia , Transdução de Sinais/efeitos dos fármacosRESUMO
In this paper, we describe the discovery and optimization of a new chemotype of isoform selective PI3Kγ inhibitors. Starting from an HTS hit, potency and physicochemical properties could be improved to give compounds such as 15, which is a potent and remarkably selective PI3Kγ inhibitor with ADME properties suitable for oral administration. Compound 15 was advanced into in vivo studies showing dose-dependent inhibition of LPS-induced airway neutrophilia in rats when administered orally.
Assuntos
Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Inibidores de Fosfoinositídeo-3 Quinase , Trifosfato de Adenosina/metabolismo , Administração Oral , Animais , Sítios de Ligação , Disponibilidade Biológica , Cristalografia por Raios X , Cães , Relação Dose-Resposta a Droga , Avaliação Pré-Clínica de Medicamentos/métodos , Inibidores Enzimáticos/administração & dosagem , Inibidores Enzimáticos/farmacocinética , Humanos , Isoenzimas , Transtornos Leucocíticos/induzido quimicamente , Transtornos Leucocíticos/tratamento farmacológico , Lipopolissacarídeos/toxicidade , Fosfatidilinositol 3-Quinases/química , Fosfatidilinositol 3-Quinases/metabolismo , Ftalimidas/química , Ratos , Relação Estrutura-AtividadeRESUMO
Ansamycins, including geldanamycin and the derivative 17-allylamino-17-demethoxygeldanamycin, and radicicol are known for their ability to tightly bind to the ATP-binding site of the amino-terminal domain region of heat shock protein 90. We have found that geldanamycin and some of its derivatives can inhibit hepatocyte growth factor/scatter factor-mediated Met tyrosine kinase receptor-dependent urokinase-plasminogen activation at femtomolar levels. Assessment is made of structural requirements for such an activity and evidence is given that distinguishes the target of such an activity from that of heat shock protein 90.