RESUMO
A cocrystal structure of T1317 (3) bound to hLXRbeta was utilized in the design of a series of substituted N-phenyl tertiary amines. Profiling in binding and functional assays led to the identification of LXR modulator GSK9772 ( 20) as a high-affinity LXRbeta ligand (IC 50 = 30 nM) that shows separation of anti-inflammatory and lipogenic activities in human macrophage and liver cell lines, respectively. A cocrystal structure of the structurally related analog 19 bound to LXRbeta reveals regions within the receptor that can affect receptor modulation through ligand modification. Mechanistic studies demonstrate that 20 is greater than 10-fold selective for LXR-mediated transrepression of proinflammatory gene expression versus transactivation of lipogenic signaling pathways, thus providing an opportunity for the identification of LXR modulators with improved therapeutic indexes.
Assuntos
Aminas/química , Aminas/farmacologia , Anti-Inflamatórios/química , Anti-Inflamatórios/farmacologia , Proteínas de Ligação a DNA/efeitos dos fármacos , Desenho de Fármacos , Receptores Citoplasmáticos e Nucleares/efeitos dos fármacos , Cristalografia por Raios X , Receptores X do Fígado , Espectroscopia de Ressonância Magnética , Espectrometria de Massas , Modelos Moleculares , Estrutura Molecular , Receptores Nucleares Órfãos , Relação Estrutura-AtividadeRESUMO
Efficient compound selection remains a key challenge in drug discovery today. The goal is to identify developable drug candidates early in the screening process while simultaneously flagging compounds with off-target effects indicative of liabilities or alternate indications. This goal overlaps but is distinct from the goal of toxicogenomics which is focused primarily on identifying toxicity signatures of lead candidates in key tissues. We propose a framework where global changes in gene expression levels in response to compounds can be used as an objective metric for early compound prioritization. We call this metric the Relative Transcription Index (RTI). RTI is a measure of the relative activity of compounds as ascertained by their effects on transcription at a genome-wide level. Compounds with a low RTI affect the expression of only a few genes whereas compounds with a high RTI affect the expression of a large number of genes. This information is useful for differentiating compounds that, based on phenotypic assays alone, may appear to be equally efficacious. Since compounds with high RTI are more likely to display off-target effects, the RTI metric, if implemented early in the screening process, can become a valuable tool for compound selection. The utility of the RTI metric is demonstrated by its application to two different gene expression datasets--one involving modulators of the liver X receptor (LXR) and the other concerning antibacterial compounds belonging to diverse mechanistic classes.
Assuntos
Antibacterianos/química , Proteínas de Ligação a DNA/genética , Avaliação Pré-Clínica de Medicamentos/métodos , Expressão Gênica , Receptores Citoplasmáticos e Nucleares/genética , Transcrição Gênica , Algoritmos , Antibacterianos/farmacologia , Bacillus subtilis/efeitos dos fármacos , Bacillus subtilis/genética , Bacillus subtilis/metabolismo , Linhagem Celular , Proteínas de Ligação a DNA/efeitos dos fármacos , Bases de Dados Genéticas , Expressão Gênica/efeitos dos fármacos , Perfilação da Expressão Gênica , Humanos , Receptores X do Fígado , Receptores Nucleares Órfãos , Receptores Citoplasmáticos e Nucleares/efeitos dos fármacos , Transcrição Gênica/efeitos dos fármacosRESUMO
Substituted 3-(phenylamino)-1H-pyrrole-2,5-diones were identified from a high throughput screen as inducers of human ATP binding cassette transporter A1 expression. Mechanism of action studies led to the identification of GSK3987 as an LXR ligand. GSK3987 recruits the steroid receptor coactivator-1 to human LXRalpha and LXRbeta with EC(50)s of 40 nM, profiles as an LXR agonist in functional assays, and activates LXR though a mechanism that is similar to first generation LXR agonists.