RESUMEN
We synthesized and identified four metabolites of acyl-coenzyme A:cholesterol O-acyltransferase (ACAT)-1 inhibitor, K-604 (1). Two of the metabolites M1 and M2, were prepared from 1 using a combination reagent of hydrogen peroxide and sodium tungstate with either phosphoric acid or trifluoroethanol as the solvent to control the regioselectivity. Upon exposure of 4b to tert-butyl hypochlorite at -78 °C, the monosulfoxidation afforded synthetic intermediate of M3 in excellent yield. The efficient synthesis of M4 was established. The in vitro metabolic study exhibited a high clearance value (720 µL/min/mg protein) of 1 using human liver microsomes. We orally administered a single dose of 10 mg/kg of 1 to monkeys because the in vitro metabolic patterns are quite similar. Fortunately, the drug concentration of 1 was much higher than those of M1, M2, M3 and M4.
Asunto(s)
Bencimidazoles/farmacocinética , Esterol O-Aciltransferasa/antagonistas & inhibidores , Animales , Bencimidazoles/química , Bencimidazoles/metabolismo , Relación Dosis-Respuesta a Droga , Humanos , Macaca fascicularis , Masculino , Microsomas Hepáticos/química , Microsomas Hepáticos/metabolismo , Estructura Molecular , Esterol O-Aciltransferasa/metabolismo , Relación Estructura-ActividadRESUMEN
An acyl-CoA:cholesterol O-acyltransferase-1 (ACAT-1/SOAT-1) inhibitor, K-604 is a promising drug candidate for the treatment of Alzheimer's disease and glioblastoma; however, it exhibits poor solubility in neutral water and low permeability across the blood-brain barrier. In this study, we report the successful delivery of K-604 to the brain via the intranasal route in mice using a hydroxycarboxylic acid solution. In cerebral tissue, the AUC of K-604 after intranasal administration (10 µL; 108 µg of K-604/mouse) was 772 ng·min/g, whereas that after oral administration (166 µg of K-604/mouse) was 8.9 ng·min/g. Thus, the index of brain-targeting efficiency was 133-fold based on the dose conversion. Even with intranasal administration of K-604 once per day for 7 days, the level of cholesteryl esters markedly decreased from 0.70 to 0.04 µmol/g in the mouse brain. Thus, this application will be a crucial therapeutic solution for ACAT-1 overexpressing diseases in the brain.
RESUMEN
2-(4-(2-((1 H-Benzo[ d]imidazol-2-yl)thio)ethyl)piperazin-1-yl)- N-(6-methyl-2,4-bis(methylthio)pyridin-3-yl)acetamide hydrochloride (K-604, 2) has been identified as an aqueous-soluble potent inhibitor of human acyl-coenzyme A:cholesterol O-acyltransferase (ACAT, also known as SOAT)-1 that exhibits 229-fold selectivity for human ACAT-1 over human ACAT-2. In our molecular design, the insertion of a piperazine unit in place of a 6-methylene chain in the linker between the head (pyridylacetamide) and tail (benzimidazole) moieties led to a marked enhancement of the aqueous solubility (up to 19 mg/mL at pH 1.2) and a significant improvement of the oral absorption (the Cmax of 2 was 1100-fold higher than that of 1 in fasted dogs) compared with those of the previously selected compound, 1. After ensuring the pharmacological effects and safety, we designated 2 as a clinical candidate, named K-604. Considering the therapeutic results of ACAT inhibitors in past clinical trials, we believe that K-604 will be useful for the treatment of incurable diseases involving ACAT-1 overexpression.
Asunto(s)
Acetil-CoA C-Acetiltransferasa/antagonistas & inhibidores , Bencimidazoles/química , Bencimidazoles/farmacología , Descubrimiento de Drogas , Inhibidores Enzimáticos/química , Inhibidores Enzimáticos/farmacología , Agua/química , Animales , Bencimidazoles/farmacocinética , Línea Celular , Inhibidores Enzimáticos/farmacocinética , Humanos , Conejos , Solubilidad , Relación Estructura-Actividad , Distribución TisularRESUMEN
Herein, we describe the discovery, synthesis, and evaluation of a novel series of spiro[chromane-2,4'-piperidine] derivatives as G-protein-coupled receptor 119 agonists. Their initial design exploited the conformational restriction in the linker-to-tail moiety, which was a key concept in this study, to give lead compound 11 (EC50â¯=â¯369â¯nM, Emaxâ¯=â¯82%). An extensive structure-activity relationship study resulted in the identification of the optimized drug candidate (R)-29 (EC50â¯=â¯54â¯nM, Emaxâ¯=â¯181%). The defining structural features of the series were a terminal benzyl-type bulky substituent and a methylene linker between the sulfonyl and phenyl groups, both of which were in the head moiety as well as the spiro-type scaffold in the linker-to-tail moiety. An in vivo oral glucose-tolerance test using C57BL/6N mice showed that (R)-29 reduced glucose excursion at a dose of 3â¯mg/kg in a dose-dependent manner.
Asunto(s)
Cromanos/farmacología , Proteínas de Unión al GTP/metabolismo , Piperidinas/metabolismo , Administración Oral , Disponibilidad Biológica , Piperidinas/farmacologíaRESUMEN
We describe our molecular design of aortic-selective acyl-coenzyme A:cholesterol O-acyltransferase (ACAT, also abbreviated as SOAT) inhibitors, their structure-activity relationships (SARs) and their pharmacokinetic (PK) and pharmacological profiles. The connection of two weak ligands-N-(2,6-diisopropylphenyl)acetamide (50% inhibitory concentration [IC50]â¯=â¯8.6⯵M) and 2-(methylthio)benzo[d]oxazole (IC50â¯=â¯31⯵M)-via a linker comprising a 6 methylene group chains yielded a highly potent molecule, 9-(benzo[d]oxazol-2-ylthio)-N-(2,6-diisopropylphenyl)nonanamide (3h) that exhibited high potency (IC50â¯=â¯0.004⯵M) toward aortic ACAT. This head-to-tail design made it possible to markedly enhance the activity to 2150- to 7750-fold and to discriminate the isoform-selectivity based on the double-induced fit mechanism. At doses of 1 and 3â¯mg/kg, 3h significantly decreased the lipid-accumulation areas in the aortic arch to 74 and 69%, respectively without reducing the plasma total cholesterol level in high fat- and cholesterol-fed F1B hamsters. Here, we demonstrate the antiatherosclerotic effect of 3hin vivo via its direct action on aortic ACAT and its powerful modulator of cholesterol level. This molecule is a potential therapeutic agent for the treatment of diseases involving ACAT-1 overexpression.
Asunto(s)
Acetamidas/farmacología , Diseño de Fármacos , Inhibidores Enzimáticos/farmacología , Esterol O-Aciltransferasa/antagonistas & inhibidores , Acetamidas/síntesis química , Acetamidas/química , Animales , Línea Celular , Cricetinae , Relación Dosis-Respuesta a Droga , Inhibidores Enzimáticos/síntesis química , Inhibidores Enzimáticos/química , Ligandos , Masculino , Ratones , Estructura Molecular , Esterol O-Aciltransferasa/metabolismo , Relación Estructura-ActividadRESUMEN
We describe the discovery and optimization of a novel series of furo[3,2-d]pyrimidines as G protein-coupled receptor 119 agonists. Agonistic activity of 4 (EC50=129nM) was improved by replacing the intramolecular hydrogen bond between the fluorine atom and the aniline hydrogen in the head moiety with a covalent C-C bond to enhance conformational restriction, which consequently gave a lead compound 12 (EC50=53nM). Optimized compound 26, which was identified by the further optimization of 12, exhibited potent activity (EC50=42nM) with improved clearance in liver microsomes and induced a 33% reduction in blood glucose area under the curve at a dose of 10mg/kg in an oral glucose tolerance test in C57BL/6N mice.
Asunto(s)
Hipoglucemiantes/química , Hipoglucemiantes/farmacología , Pirimidinas/química , Pirimidinas/farmacología , Receptores Acoplados a Proteínas G/agonistas , Administración Oral , Animales , Glucemia/análisis , Glucemia/metabolismo , Diabetes Mellitus Tipo 2/tratamiento farmacológico , Diabetes Mellitus Tipo 2/metabolismo , Prueba de Tolerancia a la Glucosa , Humanos , Hipoglucemiantes/administración & dosificación , Hipoglucemiantes/farmacocinética , Ratones Endogámicos C57BL , Pirimidinas/administración & dosificación , Pirimidinas/farmacocinética , Receptores Acoplados a Proteínas G/metabolismo , Relación Estructura-ActividadRESUMEN
The 24(S)-hydroxycholesterol (24S-OHC), which plays an important role in maintaining brain cholesterol homeostasis, has been shown to possess neurotoxicity. We have previously reported that 24S-OHC esterification by ACAT1 and the resulting lipid droplet (LD) formation are responsible for 24S-OHC-induced cell death. In the present study, we investigate the functional roles of 24S-OHC esters and LD formation in 24S-OHC-induced cell death, and we identify four long-chain unsaturated fatty acids (oleic acid, linoleic acid, arachidonic acid, and DHA) with which 24S-OHC is esterified in human neuroblastoma SH-SY5Y cells treated with 24S-OHC. Here, we find that cotreatment of cells with 24S-OHC and each of these four unsaturated fatty acids increases prevalence of the corresponding 24S-OHC ester and exacerbates induction of cell death as compared with cell death induced by treatment with 24S-OHC alone. Using electron microscopy, we find in the present study that 24S-OHC induces formation of LD-like structures coupled with enlarged endoplasmic reticulum (ER) lumina, and that these effects are suppressed by treatment with ACAT inhibitor. Collectively, these results illustrate that ACAT1-catalyzed esterification of 24S-OHC with long-chain unsaturated fatty acid followed by formation of atypical LD-like structures at the ER membrane is a critical requirement for 24S-OHC-induced cell death.
Asunto(s)
Acetil-CoA C-Acetiltransferasa/genética , Encéfalo/metabolismo , Hidroxicolesteroles/administración & dosificación , Gotas Lipídicas/metabolismo , Neuronas/metabolismo , Ácido Araquidónico/administración & dosificación , Ácido Araquidónico/metabolismo , Encéfalo/efectos de los fármacos , Encéfalo/patología , Muerte Celular/efectos de los fármacos , Línea Celular Tumoral , Retículo Endoplásmico/efectos de los fármacos , Retículo Endoplásmico/metabolismo , Esterificación/efectos de los fármacos , Regulación de la Expresión Génica/efectos de los fármacos , Humanos , Hidroxicolesteroles/metabolismo , Ácido Linoleico/administración & dosificación , Ácido Linoleico/metabolismo , Gotas Lipídicas/química , Gotas Lipídicas/efectos de los fármacos , Neuroblastoma/metabolismo , Neuronas/patología , Ácido Oléico/administración & dosificación , Ácido Oléico/metabolismoRESUMEN
Our research found that the 2-hydroxyacetophenone derivative is an outstanding linker between the 1,1-bistrifluoromethylcarbinol moiety and the imidazolidine-2,4-dione moiety to enhance the potency and ß-selectivity of liver X receptor (LXR) agonist in our head-to-tail molecular design. The incorporation of this linker is 20-fold more potent than our previous compound (2) for LXR ß agonistic activity (EC50) in a GAL-4 luciferase assay. Furthermore, we also identified 5-[5-(1-methylethoxy)pyridyl-2-yl]-5-methylimidazoline-2,4-dione (54), which lowers the lipophilicity of 2-hydroxyacetophenone derivative. We revealed that a combination of our newly developed linker and hydantoin (54) plays a pivotal role in improving the potency and selectivity of LXRß. The optically separated (-)-56 increases high-density lipoprotein cholesterol levels without elevating plasma triglyceride levels and results in a decrease of the lipid accumulation area in the aortic arch in a high-fat- and cholesterol-fed low-density lipoprotein receptor knock-out mice. In this manuscript, we report that (-)-56 is a highly potent and ß-selective LXR agonist for use in the treatment of atherosclerosis.
Asunto(s)
Acetofenonas/química , Receptores X del Hígado/agonistas , Acetofenonas/farmacología , Animales , Dieta Alta en Grasa , Ratones , Ratones Noqueados , Espectroscopía de Protones por Resonancia Magnética , Espectrometría de Masa por Ionización de ElectrosprayRESUMEN
We synthesized several candidates of 24(S)-hydroxycholesterol (24S-OHC) esters, which are involved in neuronal cell death, through catalysis with acyl-CoA:cholesterol acyltransferase-1 (ACAT-1). We studied the regioselectivity of the acylation of the secondary alcohol at the 3- or 24-position of 24S-OHC. The appropriate saturated and unsaturated long-chain fatty acids were esterified with the protected 24S-OHC and then de-protected to afford the desired esters at a satisfactory yield. We then confirmed by HPLC monitoring that the retention times of four esters of 24S-OHC, namely 3-oleate, 3-linoleate, 3-arachidonoate and 3-docosahexaenoate, were consistent with those of 24S-OHC esters observed in 24S-OHC-treated SH-SY5Y cells.
Asunto(s)
Hidroxicolesteroles/farmacología , Neuroblastoma/tratamiento farmacológico , Muerte Celular/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Humanos , Hidroxicolesteroles/síntesis química , Hidroxicolesteroles/química , Estructura Molecular , Neuroblastoma/patología , Relación Estructura-Actividad , Células Tumorales CultivadasRESUMEN
In (S)-(+)-5-(3-bromo-4-isopropoxyphen-yl)-5-methyl-imidazolidine-2,4-dione, C13H15BrN2O3, (I), the hydantoin groups are connected via inter-molecular N-Hâ¯O hydrogen bonds, forming a terraced sheet structure. In the chloro analogue, (S)-(+)-5-(3-chloro-4-isopropoxyphen-yl)-5-methyl-imidazolidine-2,4-dione, C13H15ClN2O3, (II), the inter-molecular N-Hâ¯O hydrogen-bonding network forms a flat sheet. Comparison of the crystal structures reveals that (II) is more loosely packed than (I).
RESUMEN
Despite significant reduction of cardiovascular events by statin treatment, substantial residual risk persists, driving emerging needs for the development of new therapies. We identified a novel cholesteryl ester transfer protein (CETP) inhibitor, K-312, that raises HDL and lowers LDL cholesterol levels in animals. K-312 also suppresses hepatocyte expression of proprotein convertase subtilisin/kexin 9 (PCSK9), a molecule that increases LDL cholesterol. We explored the underlying mechanism for the reduction of PCSK9 expression by K-312. K-312 inhibited in vitro human plasma CETP activity (IC50; 0.06 µM). Administration of K-312 to cholesterol-fed New Zealand White rabbits for 18 wk raised HDL cholesterol, decreased LDL cholesterol, and attenuated aortic atherosclerosis. Our search for additional beneficial characteristics of this compound revealed that K-312 decreases PCSK9 expression in human primary hepatocytes and in the human hepatoma cell line HepG2. siRNA silencing of CETP in HepG2 did not compromise the suppression of PCSK9 by K-312, suggesting a mechanism independent of CETP. In HepG2 cells, K-312 treatment decreased the active forms of sterol regulatory element-binding proteins (SREBP-1 and -2) that regulate promoter activity of PCSK9. Chromatin immunoprecipitation assays demonstrated that K-312 decreased the occupancy of SREBP-1 and SREBP-2 on the sterol regulatory element of the PCSK9 promoter. PCSK9 protein levels decreased by K-312 treatment in the circulating blood of cholesterol-fed rabbits, as determined by two independent mass spectrometry approaches, including the recently developed, highly sensitive parallel reaction monitoring method. New CETP inhibitor K-312 decreases LDL cholesterol and PCSK9 levels, serving as a new therapy for dyslipidemia and cardiovascular disease.
Asunto(s)
Anticolesterolemiantes/farmacología , Proteínas de Transferencia de Ésteres de Colesterol/antagonistas & inhibidores , LDL-Colesterol/metabolismo , Proproteína Convertasas/genética , Serina Endopeptidasas/genética , Animales , Células Cultivadas , Regulación Enzimológica de la Expresión Génica/efectos de los fármacos , Células Hep G2 , Humanos , Metabolismo de los Lípidos/efectos de los fármacos , Metabolismo de los Lípidos/genética , Masculino , Ratones , Proproteína Convertasa 9 , Proproteína Convertasas/metabolismo , Conejos , Ratas , Ratas Sprague-Dawley , Serina Endopeptidasas/metabolismoRESUMEN
A novel series of 1,3-bistrifluoromethylcarbinol derivatives that act as liver X receptor (LXR) ß-selective agonists was discovered. Structure-activity relationship studies led to the identification of molecule 62, which was more effective (Emax) and selective toward LXRß than T0901317 and GW3965. Furthermore, 62 decreased LDL-C without elevating the plasma TG level and significantly suppressed the lipid-accumulation area in the aortic arch in a Bio F1B hamster fed a diet high in fat and cholesterol. We demonstrated that our LXRß agonist would be potentially useful as a hypolipidemic and anti-atherosclerotic agent. In this manuscript, we report the design, synthesis and pharmacology of 1,3-bistrifluoromethylcarbinol derivatives.
Asunto(s)
Metanol/análogos & derivados , Receptores Nucleares Huérfanos/agonistas , Animales , Aterosclerosis/tratamiento farmacológico , Benzoatos/química , Benzoatos/farmacología , Bencilaminas/química , Bencilaminas/farmacología , Cricetinae , Diseño de Fármacos , Humanos , Hidrocarburos Fluorados/síntesis química , Hidrocarburos Fluorados/química , Hidrocarburos Fluorados/farmacología , Hipolipemiantes/síntesis química , Hipolipemiantes/química , Hipolipemiantes/farmacología , Técnicas In Vitro , Metabolismo de los Lípidos/efectos de los fármacos , Hígado/efectos de los fármacos , Hígado/metabolismo , Receptores X del Hígado , Masculino , Metanol/síntesis química , Metanol/farmacología , Ratones , Relación Estructura-Actividad , Sulfonamidas/química , Sulfonamidas/farmacologíaRESUMEN
In an attempt to molecularly design liver X receptor (LXR) ß-selective agonists, we discovered that the combination of the 2-oxochromene moiety (head) and the imidazoline-2,4-dione moiety (tail) plays an important role in the expression potency and selectivity toward LXRß. We synthesized a series of 2-oxochromene derivatives and identified 43 as a LXRß-selective agonist that increased the HDL-C level without significantly elevating the TG level and resulted in a decreased lipid-accumulation area in the aortic arch in a high-fat-and-cholesterol-fed Bio F1B hamster. In this manuscript, we report the design, synthesis and pharmacology of these 2-oxochromene derivatives.
Asunto(s)
Benzopiranos/química , Cumarinas/química , Diseño de Fármacos , Hidantoínas/química , Receptores Nucleares Huérfanos/agonistas , Animales , Aorta Torácica/efectos de los fármacos , Aorta Torácica/metabolismo , Benzopiranos/metabolismo , Benzopiranos/farmacología , HDL-Colesterol/sangre , Cumarinas/metabolismo , Cumarinas/farmacología , Cricetinae , Dieta Alta en Grasa , Hidantoínas/metabolismo , Hidantoínas/farmacología , Imidazolinas/química , Receptores X del Hígado , Receptores Nucleares Huérfanos/metabolismo , Unión Proteica , Relación Estructura-ActividadRESUMEN
In 4-fluoroisoquinoline-5-sulfonyl chloride, C(9)H(5)ClFNO(2)S, (I), one of the two sulfonyl O atoms lies approximately on the isoquinoline plane as a result of minimizing the steric repulsion between the chlorosulfonyl group and the neighbouring F atom. In (S)-(-)-4-fluoro-N-(1-hydroxypropan-2-yl)isoquinoline-5-sulfonamide, C(12)H(13)FN(2)O(3)S, (II), there are two crystallographically independent molecules (Z' = 2). The molecular conformations of these two molecules differ in that the amine group of one forms an intramolecular bifurcated hydrogen bond with the F and OH groups, whilst the other forms only a single intramolecular N-H···F hydrogen bond. The N-H···F hydrogen bonds correspond to weak coupling between the N(H) and (19)F nuclei, observed in the (1)H NMR solution-state spectra. In (S)-(-)-4-[(4-fluoroisoquinolin-5-yl)sulfonyl]-3-methyl-1,4-diazepan-1-ium chloride, C(15)H(19)FN(3)O(2)S(+)·Cl(-), (III), the isoquinoline plane is slightly deformed, suggestive of a steric effect induced by the bulky substituent on the sulfonyl group.
Asunto(s)
Azepinas/química , Isoquinolinas/química , Cristalografía por Rayos X , Enlace de Hidrógeno , Conformación Molecular , Estructura MolecularRESUMEN
Acyl-coenzyme A:cholesterol O-acyltransferase-1 (ACAT-1) plays an essential role in macrophage foam cell formation and progression of atherosclerosis. We developed a potent and selective ACAT-1 inhibitor, K-604, and tested its effects in apoE-knockout mice. Administration of K-604 to 8-week-old apoE-knockout mice for 12 weeks at a dose of 60 mg/kg/day significantly reduced macrophage-positive area and increased collagen-positive area in atherosclerotic plaques in the aorta without affecting plasma cholesterol levels or lesion areas, indicating direct plaque-modulating effects of K-604 on vascular walls independent of plasma cholesterol levels. Pactimibe, a nonselective inhibitor of ACAT-1 and ACAT-2, reduced plasma cholesterol levels but did not affect macrophage- or collagen-positive areas. The size of macrophages and cholesteryl ester contents in the aorta were reduced by K-604. Exposure of cultured human aortic smooth muscle cells to K-604 resulted in increased procollagen type 1 contents in the culture supernatant and increased procollagen type 1 mRNA levels. Procollagen production was unaffected by pactimibe even at a concentration that inhibited cholesterol esterification to the basal level. Thus, the plaque-modulating effects of K-604 can be explained by stimulation of procollagen production independent of ACAT inhibition in addition to potent inhibition of macrophage ACAT-1.
Asunto(s)
Acetil-CoA C-Acetiltransferasa/metabolismo , Apolipoproteínas E/metabolismo , Bencimidazoles/farmacología , Colágeno/metabolismo , Miocitos del Músculo Liso/citología , Animales , Aorta/citología , Células Cultivadas , Humanos , Lipoproteínas/metabolismo , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Músculo Liso/citología , FenotipoRESUMEN
Two highly deuterium-labeled compounds, (R)-K-13675-d(11) and (R)-K-13675-d(7), were prepared for use as internal standards for low-level quantification of plasma drugs by LC/MS/MS. We successfully demonstrated their utility in pharmacokinetic studies for sensitive and precise drug quantification.
Asunto(s)
Benzoxazoles/sangre , Butiratos/sangre , PPAR alfa/agonistas , Animales , Benzoxazoles/química , Butiratos/síntesis química , Butiratos/química , Butiratos/farmacocinética , Cromatografía Liquida/normas , Deuterio/química , Marcaje Isotópico , PPAR alfa/metabolismo , Ratas , Estándares de Referencia , Estereoisomerismo , Espectrometría de Masas en Tándem/normasRESUMEN
A combination of benzoxazole, phenoxyalkyl side chain, and phenoxybutyric acids was identified as a highly potent and selective human peroxisome proliferator-activated receptor alpha (PPARalpha) agonist. The synthesis, structure-activity relationship (SAR) studies, and in vivo activities of the representative compounds are described.
Asunto(s)
Compuestos Heterocíclicos/química , Compuestos Heterocíclicos/farmacología , PPAR alfa/agonistas , Alérgenos , Animales , Antígenos de Plantas , Diseño de Fármacos , Humanos , Hipolipemiantes/química , Hipolipemiantes/farmacología , Ratones , Ratones Transgénicos , Estructura Molecular , Proteínas de Plantas , Ratas , Ratas Sprague-Dawley , Relación Estructura-ActividadRESUMEN
BACKGROUND: Acyl-coenzyme A:cholesterol O-acyltransferase-1 (ACAT-1), a major ACAT isozyme in macrophages, plays an essential role in foam cell formation in atherosclerotic lesions. However, whether pharmacological inhibition of macrophage ACAT-1 causes exacerbation or suppression of atherosclerosis is controversial. METHODS AND RESULTS: We developed and characterized a novel ACAT inhibitor, K-604. The IC(50) values of K-604 for human ACAT-1 and ACAT-2 were 0.45 and 102.85 micromol/L, respectively, indicating that K-604 is 229-fold more selective for ACAT-1. Kinetic analysis indicated that the inhibition was competitive with respect to oleoyl-coenzyme A with a K(i) value of 0.378 micromol/L. Exposure of human monocyte-derived macrophages to K-604 inhibited cholesterol esterification with IC(50) of 68.0 nmol/L. Furthermore, cholesterol efflux from THP-1 macrophages to HDL(3) or apolipoprotein A-I was enhanced by K-604. Interestingly, administration of K-604 to F1B hamsters on a high-fat diet at a dose of >or=1mg/kg suppressed fatty streak lesions without affecting plasma cholesterol levels. CONCLUSIONS: K-604, a potent and selective inhibitor of ACAT-1, suppressed the development of atherosclerosis in an animal model without affecting plasma cholesterol levels, providing direct evidence that pharmacological inhibition of ACAT-1 in the arterial walls leads to suppression of atherosclerosis.