RESUMO
Farnesoid X receptor α (FXRα) as a bile acid sensor plays potent roles in multiple metabolic processes, and its antagonist has recently revealed special interests in the treatment of metabolic disorders, although the underlying mechanisms still remain unclear. Here, we identified that the small molecule N-benzyl-N-(3-(tert-butyl)-4-hydroxyphenyl)-2,6-dichloro-4-(dimethylamino) benzamide (NDB) functioned as a selective antagonist of human FXRα (hFXRα), and the crystal structure of hFXRα ligand binding domain (hFXRα-LBD) in complex with NDB was analyzed. It was unexpectedly discovered that NDB induced rearrangements of helix 11 (H11) and helix 12 (H12, AF-2) by forming a homodimer of hFXRα-LBD, totally different from the active conformation in monomer state, and the binding details were further supported by the mutation analysis. Moreover, functional studies demonstrated that NDB effectively antagonized the GW4064-stimulated FXR/RXR interaction and FXRα target gene expression in primary mouse hepatocytes, including the small heterodimer partner (SHP) and bile-salt export pump (BSEP); meanwhile, administration of NDB to db/db mice efficiently decreased the gene expressions of phosphoenolpyruvate carboxykinase (PEPCK), glucose 6-phosphatase (G6-pase), small heterodimer partner, and BSEP. It is expected that our first analyzed crystal structure of hFXRα-LBD·NDB will help expound the antagonistic mechanism of the receptor, and NDB may find its potential as a lead compound in anti-diabetes research.
Assuntos
Benzamidas/farmacologia , Receptores Citoplasmáticos e Nucleares/antagonistas & inibidores , Receptores Citoplasmáticos e Nucleares/química , Membro 11 da Subfamília B de Transportadores de Cassetes de Ligação de ATP , Transportadores de Cassetes de Ligação de ATP/antagonistas & inibidores , Transportadores de Cassetes de Ligação de ATP/genética , Transportadores de Cassetes de Ligação de ATP/metabolismo , Animais , Benzamidas/química , Cristalografia por Raios X , Regulação da Expressão Gênica , Glucose-6-Fosfatase/antagonistas & inibidores , Glucose-6-Fosfatase/genética , Glucose-6-Fosfatase/metabolismo , Células Hep G2 , Hepatócitos/citologia , Hepatócitos/efeitos dos fármacos , Hepatócitos/metabolismo , Humanos , Isoxazóis/antagonistas & inibidores , Isoxazóis/farmacologia , Masculino , Camundongos , Camundongos Knockout , Simulação de Acoplamento Molecular , Mutação , Fosfoenolpiruvato Carboxiquinase (ATP)/antagonistas & inibidores , Fosfoenolpiruvato Carboxiquinase (ATP)/genética , Fosfoenolpiruvato Carboxiquinase (ATP)/metabolismo , Cultura Primária de Células , Isoformas de Proteínas/agonistas , Isoformas de Proteínas/antagonistas & inibidores , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Receptores Citoplasmáticos e Nucleares/agonistas , Receptores Citoplasmáticos e Nucleares/genética , Receptores Citoplasmáticos e Nucleares/metabolismo , Receptores para Leptina/deficiência , Receptores para Leptina/genética , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Receptores X de Retinoides/agonistas , Receptores X de Retinoides/genética , Receptores X de Retinoides/metabolismo , Transdução de SinaisRESUMO
O-Alkylated quercetin analogs were synthesized and their anticancer activities were assessed by a high-throughout screening (HTS) method. The structure-activity relationships (SAR) showed that introduction of long alkyl chain such as propyl group at the C-3 OH position or short alkyl chain such as ethyl group at the C-4' OH position were very important for keeping inhibitory activities against the 16 cancer cell lines. Furthermore, when the two n-butyl groups were introduced into the C-3, C-7 or C-4', C-7 positions, the anticancer activity was enhanced.
Assuntos
Antineoplásicos/farmacologia , Quercetina/farmacologia , Alquilação , Antineoplásicos/síntese química , Antineoplásicos/química , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Células HeLa , Ensaios de Triagem em Larga Escala , Humanos , Estrutura Molecular , Quercetina/síntese química , Quercetina/química , Relação Estrutura-AtividadeRESUMO
Using a high-throughout screening approach, the anticancer activities of 16 O-methylated (OMe) analogs of quercetin were assessed. The structure-activity relationships showed that OMe moieties at the 4' and/or 7 positions were important for maintaining inhibitory activities against the 16 cancer cell lines. Furthermore, when the OH groups at the 3' and 4' positions were both replaced by OMe moieties, anticancer activity was enhanced.