AV-65, a novel Wnt/ß-catenin signal inhibitor, successfully suppresses progression of multiple myeloma in a mouse model.

Multiple myeloma (MM) is a malignant neoplasm of plasma cells. Although new molecular targeting agents against MM have been developed based on the better understanding of the underlying pathogenesis, MM still remains an incurable disease. We previously demonstrated that ß-catenin, a downstream effector in the Wnt pathway, is a potential target in MM using RNA interference in an in vivo experimental mouse model. In this study, we have screened a library of more than 100 000 small-molecule chemical compounds for novel Wnt/ß-catenin signaling inhibitors using a high-throughput transcriptional screening technology. We identified AV-65, which diminished ß-catenin protein levels and T-cell factor transcriptional activity. AV-65 then decreased c-myc, cyclin D1 and survivin expression, resulting in the inhibition of MM cell proliferation through the apoptotic pathway. AV-65 treatment prolonged the survival of MM-bearing mice. These findings indicate that this compound represents a novel and attractive therapeutic agent against MM. This study also illustrates the potential of high-throughput transcriptional screening to identify candidates for anticancer drug discovery.

Novel nonpeptide CCK-B antagonists: design and development of quinazolinone derivatives as potent, selective, and orally active CCK-B antagonists.

We have designed a novel series of CCK-B receptor antagonists by combining key pharmacophores, an arylurea moiety of 1 and a quinazolinone ring of 3, from two known series. Our earlier studies showed that compounds with methylene linkers in our "target" produced moderate binding affinity and selectivity for CCK-B receptors, whereas its higher and lower homologues resulted in loss of affinity. Introduction of -NH- as a linker dramatically enhanced binding affinity and selectivity for CCK-B receptors, thus providing several compounds with single-digit nanomolar binding affinity and excellent selectivity. Analogous to the earlier studies of the series of quinazolinone derivatives 3, we also found 3-isopropoxyphenyl as a preferred substitution on the N-3 quinazolinone. Electron-withdrawing substitutions on the urea terminal phenyl ring enhanced the CCK-B potency. Representative compounds of this series were tested in the functional assay and showed pure antagonist profiles. Compounds 51 and 61 were orally active in the elevated rat X-maze test. These compounds were also evaluated for their pharmacokinetic profile. The absolute oral bioavailability of compound 61 was 22% in rats.

Second generation "peptoid" CCK-B receptor antagonists: identification and development of N-(adamantyloxycarbonyl)-alpha-methyl-(R)-tryptophan derivative (CI-1015) with an improved pharmacokinetic profile.

We have previously described the design and development of CI-988, a peptoid analogue of CCK-4 with excellent binding affinity and selectivity for the CCK-B receptor. Due to its anxiolytic profile in animal models of anxiety, this compound was developed as a clinical candidate. However, during its development, it was determined that CI-988 had low bioavailability in both rodent and nonrodent species. In the clinic, it was further established that CI-988 had poor bioavailability. Thus, there was a need to identify an analogue with an improved pharmacokinetic (PK) profile. The poor bioavailability was attributed to poor absorption and efficient hepatic extraction. We envisaged that reducing the molecular weight of the parent compound (5, MW = 614) would lead to better absorption. Thus, we synthesized a series of analogues in which the key alpha-methyltryptophan and adamantyloxycarbonyl moieties, required for receptor binding, were kept intact and the C-terminus was extensively modified. This SAR study led to the identification of tricyclo[3.3.1.1(3,7)]dec-2-yl [1S-[1 alpha(S*)2 beta]-[2-[(2-hydroxycyclohexyl)amino]-1-(1H-indol-3- ylmethyl)-1-methyl-2-oxoethyl]carbamate (CI-1015, 31) with binding affinities of 3.0 and 2900 nM for the CCK-B and CCK-A receptors, respectively. The compound showed CCK-B antagonist profile in the rat ventromedial hypothalamus assay with a Ke of 34 nM. It also showed an anxiolytic like profile orally in a standard anxiety paradigm (X-maze) with a minimum effective dose (MED) of 0.1 microgram/kg. Although the compound is less water soluble than CI-988, oral bioavailability in rat was improved nearly 10 times relative to CI-988 when dosed in HP beta CD. The blood-brain permeability of CI-1015 (31) was also enhanced relative to CI-988 (5). On the basis of the overall improved pharmacokinetic profile as well as enhanced brain penetration, CI-1015 (31) was chosen as a development candidate.

7 beta-hydroxy bile alcohols: facile synthesis and 2D 1H NMR studies of 5 beta-cholestane-3 alpha, 7 beta, 12 alpha, 25-tetrol.

A rapid and easily performed procedure for the synthesis of 5 beta-cholestane-3 alpha, 7 beta, 12 alpha, 25-tetrol by means of an efficient homologation sequence of the intermediate, 3 alpha, 7 beta, 12 alpha-triformyloxy-24-oxo-25-diazo-25-homo-5 beta-cholane is described. The reaction sequence involved treating the intermediate, alpha-diazoketone in methanol with 3% AgNO3 or Ag2O, anhydrous Na2CO3, Na2S2O/H2O resulting in the formation of homoursocholic acid in high yield. Esterification of the homoursocholic acid in methanol containing a catalytic amount of methanesulfonic acid under microwave irradiation conditions gave methyl homourscholate. The subsequent treatment of methyl homoursocholate with methyl magnesium iodide provided 5 beta-cholestane-3 alpha, 7 beta, 12 alpha, 25-tetrol in 88% yield. The products and synthetic intermediates prepared in these studies were fully characterized by the results of 1D and 2D NMR, and high-resolution mass spectral studies. These studies will help in further investigation of the defect of cholic acid biosynthesis in patients with cerebrotendinous xanthomatosis (CTX) as well as other inborn errors of bile acid metabolism.

Bioisosterism in drug design: identification of and structure-activity relationships in a series of glycine anilide ACAT inhibitors.

To examine the effects of bioisosteric replacement on the biological activity of our previously disclosed disubstituted urea inhibitors of the enzyme acyl-CoA:cholesterol acyltransferase (ACAT), we prepared a series of N'-substituted and N',N'-disubstituted glycine anilides. These compounds were tested for the ability to inhibit ACAT in vitro and lower plasma total cholesterol in cholesterol-fed rats given a single high-fat, high-cholesterol meal. ACAT inhibitory potency was greatest in compounds containing 2,6-diisopropyl substituents in the anilide portion with the glycine nitrogen substituted by a 1,1-diphenylmethyl moiety. Small improvements in potency in vitro were obtained by substitution of electron donating groups in the 2-, 3- or 5-positions of the aryl rings of the 1,1-diphenylmethyl moiety, but not by substitution in the 4-position. In vitro potency was maintained, but not improved by acylation of the glycine nitrogen. Through a QSAR analysis of in vitro ACAT inhibition for this set of compounds, an equation could be derived which accounted for 85% of the variance in the dataset. An optimal clogp of 6.65 was found, comparable to that found for other series of ACAT inhibitors. In general, compounds from this series displayed inhibitory potency against ACAT in vitro and hypocholesterolemic activity in the in vivo rat model of hypercholesterolemia comparable to that found with the ureas.

Bile alcohol glucuronides: regioselective O-glucuronidation of 5 beta-cholestane-3 alpha,7 alpha,12 alpha,25-tetrol and 24-nor-5 beta-cholestane-3 alpha,7 alpha,12 alpha,25-tetrol.

A facile and regiocontrolled procedure for the preparation of 5-beta-cholestane-3 alpha,7 alpha,12 alpha,25-tetrol-3-O-beta-D-glucuronide and its corresponding C-26 analogue is described. The method involves direct coupling of bile alcohols, namely, 5 beta-cholestane-3 alpha,7 alpha,12 alpha,25-tetrol and 24-nor-5 beta-cholestane-3 alpha,7 alpha,12 alpha,25-tetrol to methyl (tetra-O-acetyl-beta-D-glucopyranuronate) in the presence of a Lewis acid, tin(IV) chloride, in dichloromethane. The resulting anomeric pairs of 1,2-trans- and 1,2-cis-glucuronides of tetrols were resolved by analytical and preparative thin-layer chromatography, and their identities were established by high-resolution 1H NMR spectroscopy and by chemical-ionization and fast-atom-bombardment mass spectrometry. The method described has a practical advantage over the traditional two-step synthesis involving bromides as it is more efficient and uses inexpensive and less toxic materials. It is suggested that these compounds will be useful for studying permeability of the blood-brain barrier in cerebrotendinous xanthomatosis (CTX).

Stereoselective synthesis of (24R and 24S) 5 beta-cholestane-3 alpha,7 alpha,12 alpha,24,25-pentols and (25R and 25S) 5 beta-cholestane-3 alpha,7 alpha,12 alpha,25,26-pentols using a modified osmium-catalyzed Sharpless asymmetric dihydroxylation process.

Described herein are the stereoselective syntheses of the (24R, 24S) and (25R, 25S) isomers of 5 beta-cholestane-3 alpha,7 alpha,12 alpha,24,25-pentols and 5 beta-cholestane-3 alpha,7 alpha,12 alpha,25,26-pentols by using a modified osmium-catalyzed Sharpless asymmetric dihydroxylation process. Also presented herein are the results of lanthanide-induced CD Cotton effect measurements and 1H- and 13C-nuclear magnetic resonance studies of (24R, 24S) and (25R, 25S)-5 beta-cholestanepentols and their derivatives. These compounds were required to study the biosynthesis of cholic acid from cholesterol.

Lithium hydroxide/aqueous methanol: mild reagent for the hydrolysis of bile acid methyl esters.

An efficient and convenient procedure for the hydrolysis of bile acid methyl esters is described. This is achieved by the addition of aqueous lithium hydroxide in methanol/dioxane (or tetrahydrofuran) at room temperature. Under these conditions, the formates as well as the acetate derivatives were also hydrolyzed, and the desired bile acids were isolated in 86 to 94% yield.

Secular variations in the abundances of heavy nuclei in cosmic rays.

The ratios of fluxes of heavy cosmic-ray nuclei [(30