RESUMO
A novel series of (E)-1-((2-(1-methyl-1H-imidazol-5-yl) quinolin-4-yl) methylene) thiosemicarbazides was discovered as potent inhibitors of IKKß. In this Letter we document our efforts at further optimization of this series, culminating in 2 with submicromolar potency in a HWB assay and efficacy in a CIA mouse model.
Assuntos
Quinase I-kappa B/antagonistas & inibidores , Inibidores de Proteínas Quinases/química , Quinolinas/química , Semicarbazidas/química , Tioureia/análogos & derivados , Animais , Cães , Feminino , Hepatócitos/metabolismo , Ensaios de Triagem em Larga Escala , Humanos , Quinase I-kappa B/metabolismo , Macaca mulatta , Masculino , Camundongos , Inibidores de Proteínas Quinases/síntese química , Inibidores de Proteínas Quinases/farmacocinética , Quinolinas/síntese química , Quinolinas/farmacocinética , Ratos , Semicarbazidas/síntese química , Semicarbazidas/farmacocinética , Relação Estrutura-Atividade , Tioureia/síntese química , Tioureia/química , Tioureia/farmacocinéticaRESUMO
A novel series of (E)-1-((2-(1-methyl-1H-imidazol-5-yl) quinolin-4-yl) methylene) thiosemicarbazides was discovered as potent inhibitors of IKKß. In this Letter we document our early efforts at optimization of the quinoline core, the imidazole and the semithiocarbazone moiety. Most potency gains came from substitution around the 6- and 7-positions of the quinoline ring. Replacement of the semithiocarbazone with a semicarbazone decreased potency but led to some measurable exposure.
Assuntos
Quinase I-kappa B/antagonistas & inibidores , Inibidores de Proteínas Quinases/química , Semicarbazidas/química , Animais , Cães , Feminino , Ensaios de Triagem em Larga Escala , Quinase I-kappa B/metabolismo , Masculino , Microssomos/metabolismo , Inibidores de Proteínas Quinases/síntese química , Inibidores de Proteínas Quinases/farmacocinética , Quinolinas/química , Ratos , Semicarbazidas/síntese química , Semicarbazidas/farmacocinética , Relação Estrutura-AtividadeRESUMO
Phorbol 12-myristate-13-acetate (PMA), a potent tumor promoter and activator of most protein kinase C (PKC) isotypes, was found to significantly inhibit the growth of low population density (1-5% confluency) NIH 3T3 cells. Higher cell population density (above 10% confluency) provided protection from this growth inhibitory effect of PMA. PMA-induced growth arrest is accompanied by an elevation in the level of p21(Cip1) protein, along with cell cycle arrest at the G1/S transition. Activation of PKC is required for this growth inhibitory response since the pan PKC inhibitor GF109203 blocked this effect of PMA. However, the classical PKC inhibitor Gö6976 had no effect, strongly suggesting the involvement of novel PKC isotypes (delta and/or epsilon). Overexpression of PKCepsilon, but not PKCdelta, was found to potentiate PMA-induced growth inhibition. Overexpression of a kinase-inactive dominant-negative mutant of PKCepsilon (K437R) decreased the growth inhibitory effect of PMA and also blocked the PMA-induced increase in the level of p21(Cip1) protein. Taken together, these results indicate that PMA has a cell population density-dependent effect on the growth of NIH 3T3 cells and that the PMA growth inhibitory effect at low cell population density is mediated through activation of PKCepsilon.
