RESUMO
ATP-citrate lyase is the primary enzyme responsible for the synthesis of cytosolic acetyl-CoA in many tissues. Inhibitors of the enzyme represent a potentially novel class of hypolipidemic agent, which are anticipated to have combined hypocholesterolemic and hypotriglyceridemic properties. A series of 2-substituted butanedioic acids have been designed and synthesized as inhibitors of the enzyme. The best compounds, 58, 68, 71, 74 have reversible Ki's in the 1-3 microM range against the isolated rat enzyme. As representative of this compound class, 58, has been shown to exert its inhibitory action through a mainly competitive mechanism with respect to citrate and a noncompetitive one with respect to CoA. None of the inhibitors were able to inhibit cholesterol and/or fatty acid synthesis in HepG2 cells. This has been attributed to the adverse physicochemical properties of the molecules leading to a lack of cell penetration. Despite this, a lead structural class of compound has been identified with the potential for modification into potent, cell-penetrant, and efficacious inhibitors of ATP-citrate lyase.
Assuntos
ATP Citrato (pro-S)-Liase/antagonistas & inibidores , Inibidores Enzimáticos/síntese química , Hipolipemiantes/síntese química , Animais , Desenho de Fármacos , Inibidores Enzimáticos/farmacologia , Humanos , Inibidores de Hidroximetilglutaril-CoA Redutases , Hipolipemiantes/farmacologia , Cinética , Ratos , Relação Estrutura-Atividade , Células Tumorais CultivadasRESUMO
A series of (3R,5S)-omega-substituted-3-carboxy-3, 5-dihydroxyalkanoic acids have been synthesized and evaluated as inhibitors of the recombinant human form of ATP-citrate lyase. The best of these have Ki's in the 200-1000 nM range. As the corresponding thermodynamically favored gamma-lactone prodrugs, a number of compounds are able to inhibit cholesterol and fatty acid synthesis in HepG2 cells and reduce plasma triglyceride levels in vivo. The best of these, compound 77, is able to induce clear hypocholesterolemic and hypotriglyceridaemic responses when administered orally to rat and dog. These results provide evidence to support the hypothesis that compounds which inhibit ATP-citrate lyase have the potential to be a novel class of hypolipidemic agent, which possess combined hypocholesterolemic and hypotriglyceridemic activities.
Assuntos
ATP Citrato (pro-S)-Liase/antagonistas & inibidores , Inibidores Enzimáticos/síntese química , Ácidos Graxos/química , Furanos/síntese química , Hipolipemiantes/síntese química , Pró-Fármacos/síntese química , Administração Oral , Animais , Anticolesterolemiantes/administração & dosagem , Anticolesterolemiantes/síntese química , Anticolesterolemiantes/química , Anticolesterolemiantes/farmacologia , Linhagem Celular , Colesterol/sangue , Cães , Inibidores Enzimáticos/administração & dosagem , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Ácidos Graxos/farmacologia , Furanos/administração & dosagem , Furanos/química , Furanos/farmacologia , Humanos , Hipolipemiantes/administração & dosagem , Hipolipemiantes/química , Hipolipemiantes/farmacologia , Lipídeos/biossíntese , Lipoproteínas VLDL/sangue , Pró-Fármacos/administração & dosagem , Pró-Fármacos/química , Pró-Fármacos/farmacologia , Ratos , Proteínas Recombinantes/antagonistas & inibidores , Relação Estrutura-Atividade , Triglicerídeos/sangueRESUMO
Cathepsin K (EC 3.4.22.38), a cysteine protease of the papain superfamily, is predominantly expressed in osteoclasts and has been postulated as a target for the treatment of osteoporosis. Crystallographic and structure--activity studies on a series of acyclic ketone-based inhibitors of cathepsin K have led to the design and identification of two series of cyclic ketone inhibitors. The mode of binding for four of these cyclic and acyclic inhibitors to cathepsin K is discussed and compared. All of the structures are consistent with addition of the active site thiol to the ketone of the inhibitors with the formation of a hemithioketal. Cocrystallization of the C-3 diastereomeric 3-amidotetrahydrofuran-4-one analogue 16 with cathepsin K showed the inhibitor to occupy the unprimed side of the active site with the 3S diastereomer preferred. This C-3 stereochemical preference is in contrast to the X-ray cocrystal structures of the 3-amidopyrrolidin-4-one inhibitors 29 and 33 which show these inhibitors to prefer binding of the 3R diastereomer. The 3-amidopyrrolidin-4-one inhibitors were bound in the active site of the enzyme in two alternate directions. Epimerization issues associated with the labile alpha-amino ketone diastereomeric center contained within these inhibitor classes has proven to limit their utility despite promising pharmacokinetics displayed in both series of compounds.
Assuntos
Catepsinas/antagonistas & inibidores , Inibidores Enzimáticos/síntese química , Cetonas/síntese química , Animais , Sítios de Ligação , Catepsina K , Cromatografia Líquida , Cristalografia por Raios X , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacocinética , Furanos/síntese química , Furanos/química , Furanos/farmacocinética , Humanos , Cetonas/química , Cetonas/farmacocinética , Espectrometria de Massas , Modelos Moleculares , Estrutura Molecular , Piperidinas/síntese química , Piperidinas/química , Piperidinas/farmacocinética , Piranos/síntese química , Piranos/química , Piranos/farmacocinética , Pirrolidinonas/síntese química , Pirrolidinonas/química , Pirrolidinonas/farmacocinética , Ratos , Estereoisomerismo , Relação Estrutura-AtividadeRESUMO
The diastereoselective synthesis of a novel class of cathepsin K inhibitors together with their cathepsin K affinity and stability towards aqueous buffer is reported.
Assuntos
Catepsinas/antagonistas & inibidores , Inibidores de Cisteína Proteinase/síntese química , Cetonas/farmacologia , Soluções Tampão , Catepsina K , Técnicas de Química Combinatória , Inibidores de Cisteína Proteinase/farmacologia , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/farmacologia , Furanos/química , Compostos Heterocíclicos/síntese química , Compostos Heterocíclicos/farmacologia , Humanos , Cetonas/síntese química , Cinética , Relação Estrutura-AtividadeRESUMO
Using solid-phase synthesis, a library of novel cyclic alkoxyketones has been constructed which show strong inhibitory activity against the cysteine protease, cathepsin K (EC 3.4.22.38).
Assuntos
Catepsinas/antagonistas & inibidores , Inibidores de Cisteína Proteinase/síntese química , Cetonas/farmacologia , Sítios de Ligação , Catepsina K , Técnicas de Química Combinatória , Inibidores de Cisteína Proteinase/farmacologia , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/farmacologia , Furanos/química , Compostos Heterocíclicos/síntese química , Compostos Heterocíclicos/farmacologia , Humanos , Cetonas/síntese química , Relação Estrutura-Atividade , Especificidade por SubstratoRESUMO
The preparation and biological evaluation of a series of indolopiperidine CCR2B receptor antagonists possessing a conformationally restricted C-5 linker chain in combination with a restricted piperidine ring are described. Compared to the parent compound 1, analogue 8 shows a dramatic improvement in selectivity against a range of 5-HT and dopaminergic receptors.
Assuntos
Indóis/farmacologia , Piperidinas/farmacologia , Receptores de Quimiocinas/antagonistas & inibidores , Antagonistas de Dopamina/síntese química , Antagonistas de Dopamina/química , Antagonistas de Dopamina/farmacologia , Indóis/síntese química , Indóis/química , Conformação Molecular , Piperidinas/síntese química , Piperidinas/química , Receptores CCR2 , Receptores de Quimiocinas/metabolismo , Antagonistas da Serotonina/síntese química , Antagonistas da Serotonina/química , Antagonistas da Serotonina/farmacologia , Relação Estrutura-AtividadeRESUMO
Aryl hydroxylamine derivatives have been synthesised that are some of the most potent inhibitors of hCMV protease prepared to date (IC50 14-60 nM). Mass spectrometry studies indicate that oxazinone derived hydroxylamines inhibit the enzyme by acylation of Ser132 whereas non-oxazinone derived hydroxylamines appear to inhibit via formation of a sulfinanilide at Cys138.
Assuntos
Anti-Infecciosos/síntese química , Citomegalovirus/enzimologia , Hidroxilaminas/síntese química , Serina Endopeptidases/metabolismo , Inibidores de Serina Proteinase/síntese química , Sequência de Aminoácidos , Anti-Infecciosos/farmacologia , Sítios de Ligação , Infecções por Citomegalovirus , Humanos , Hidroxilaminas/farmacologia , Espectrometria de Massas , Dados de Sequência Molecular , Estrutura Molecular , Fragmentos de Peptídeos/química , Inibidores de Serina Proteinase/farmacologia , TripsinaRESUMO
ATP citrate (pro-S)-lyase (EC 4.1.3.8), a cytosolic enzyme that generates acetyl-CoA for cholesterol and fatty acid synthesis de novo, is a potential target for hypolipidaemic intervention. Here we describe the biological effects of the inhibition of ATP citrate-lyase on lipid metabolism in Hep G2 cells, and plasma lipids in rats and dogs, by using SB-204990, the cell-penetrant gamma-lactone prodrug of the potent ATP citrate-lyase inhibitor SB-201076 (Ki=1 microM). Consistent with an important role of ATP citrate-lyase in the supply of acetyl-CoA units for lipid synthesis de novo, SB-204990 inhibited cholesterol synthesis and fatty acid synthesis in Hep G2 cells (dose-related inhibition of up to 91% and 82% respectively) and rats (76% and 39% respectively). SB-204990, when administered orally to rats, was absorbed into the systemic circulation; pharmacologically relevant concentrations of SB-201076 were recovered in the liver. When administered in the diet (0.05-0. 25%, w/w) for 1 week, SB-204990 caused a dose-related decrease in plasma cholesterol (by up to 46%) and triglyceride levels (by up to 80%) in rats. This hypolipidaemic effect could be explained, at least in part, by a decrease (up to 48%) in hepatic very-low-density lipoprotein (VLDL) production as measured by the accumulation of VLDL in plasma after injection of Triton WR-1339. SB-204990 (25 mg/kg per day) also decreased plasma cholesterol levels (by up to 23%) and triglyceride levels (by up to 38%) in the dog, preferentially decreasing low-density lipoprotein compared with high-density lipoprotein cholesterol levels. Overall these results are consistent with the concept that ATP citrate-lyase is an important enzyme in controlling substrate supply for lipid synthesis de novo and a potential enzyme target for hypolipidaemic intervention.
Assuntos
ATP Citrato (pro-S)-Liase/metabolismo , Clorobenzenos/farmacologia , Hipolipemiantes/farmacologia , Lactonas/farmacologia , Lipídeos/sangue , Fígado/enzimologia , ATP Citrato (pro-S)-Liase/antagonistas & inibidores , Animais , Disponibilidade Biológica , Colesterol/biossíntese , Colesterol/sangue , Cães , Inibidores Enzimáticos/farmacologia , Ácidos Graxos não Esterificados/metabolismo , Homeostase/efeitos dos fármacos , Humanos , Lactonas/farmacocinética , Masculino , Pró-Fármacos/farmacologia , Ratos , Ratos Sprague-Dawley , Proteínas Recombinantes/metabolismo , Triglicerídeos/sangue , Células Tumorais CultivadasRESUMO
Apolipoprotein (APO) E*3-Leiden mice with impaired chylomicron and VLDL (very low density lipoprotein) remnant metabolism display hyperlipidaemia and atherosclerosis. In the present study, these mice were used for testing the hypolipidaemic effect of two marketed agents, lovastatin (CAS 75330-75-5) and gemfibrozil (CAS 25812-30-0) as well as a novel compound, SB 204990 (the 5-ring lactone of +/-(3R*,5S*) 3-carboxy-11-(2,4-dichlorophenyl)-3,5-dihydroxyundecanoic acid, CAS 154566-12-8), a potent inhibitor of cholesterol and fatty acid synthesis at the level of ATP-citrate lyase. APOE*3-Leiden mice were fed a saturated fat and cholesterol-rich diet supplemented with either 0.05 or 0.1% w/w of lovastatin, 0.1 or 0.2% w/w of gemfibrozil or 0.1 or 0.2% w/w of SB 204990. Lovastatin showed a dose-related decrease in plasma cholesterol levels (up to -20%) due to a lowering of LDL and HDL (low density resp. high density lipoprotein)-cholesterol (-20 and -18%, respectively), while plasma triglyceride levels were unaffected. Gemfibrozil had no effect on plasma total cholesterol levels but gave significant dose-dependent decreases in plasma (VLDL) triglyceride levels (up to -53%). SB 204990 resulted in a dose-dependent reduction of plasma cholesterol (up to -29%) by lowering VLDL, LDL and HDL-cholesterol (-50, -20 and -20%, respectively). In addition, a strong dose dependent reduction of plasma (VLDL) triglycerides up to -43% was observed with this compound. Although the effects of gemfibrozil and SB 204990 were not simply explained by changes in a single determinant of VLDL metabolism--no effects of these drugs were seen on post-heparin plasma lipoprotein lipase activity, in vivo rate of VLDL synthesis or hepatic apoC-III mRNA levels--APOE*3-Leiden mice were found to give robust hypolipidaemic responses to these test compounds. The responsiveness to hypolipidaemic therapy combined with a clear relationship between aortic lesion size and plasma cholesterol exposure, as demonstrated previously, makes this mouse an attractive model for the testing of anti-atherosclerotic properties of hypolipidaemic drugs.