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Pancreatic ductal adenocarcinoma (PDAC) is one of the most debilitating malignancies in humans, and one of the reasons for this is the inability to diagnose this disease early in its development. To search for biomarkers that can be used for early diagnosis of PDAC, we established a rat model of human PDAC in which expression of a human K-ras(G12V) oncogene and induction of PDAC are regulated by the Cre/lox system. In the present study, transgenic rats bearing PDAC and control transgenic rats with normal pancreatic tissues were used for metabolomic analysis of serum and pancreatic tissue by non-targeted and targeted gas chromatography-mass spectrometry and transcriptomic analysis of pancreatic tissue by microarray. Comparison of the metabolic profiles of the serum and pancreatic tissue of PDAC-bearing and control rats identified palmitoleic acid as a metabolite, which was significantly decreased in the serum of PDAC-bearing animals. Transcriptomic analysis indicated that several transcripts involved in anaerobic glycolysis and nucleotide degradation were increased and transcripts involved in the trichloroacetic acid cycle were decreased. Other transcripts that were changed in PDAC-bearing rats were adenosine triphosphate citrate lyase (decreased: fatty acid biosynthesis), fatty acid synthase (increased: fatty acid biosynthesis) and arachidonate 5-lipoxygenase activating protein (increased: arachidonic acid metabolism). Overall, our results suggest that the decreased serum levels of palmitoleic acid in rats with PDAC was likely due to its decrease in pancreatic tissue and that palmitoleic acid should be investigated in human samples to assess its diagnostic significance as a serum biomarker for human PDAC.

To estimate the metabolic profile of trans-permethrin in humans, a comparison of the in vitro metabolism of trans-permethrin in humans and rats was conducted using hepatic microsomes, and cytochrome P450 and UDP-glucuronyltransferase isoforms, which catalyze the metabolism of 3-phenoxybenzyl alcohol (PBalc) and 3-phenoxybenzoic acid (PBacid), respectively. In humans and rats, the major metabolic reaction of trans-permethrin in microsomal incubations was the cleavage of ester linkage to give PBalc, followed by oxidation to 4'-OH-PBalc, 4'-OH-PBacid, and PBacid. As to 4'-hydroxylation of PBalc, several CYPs were able to catalyze the reaction, and CYP2E1 was identified as a predominant isoform. PBacid and its conjugates (glucuronide and glycine) are major urinary metabolites of trans-permethrin in mammals. PBacid is also a metabolite of several pyrethroids, and has been used as a biomarker of human exposure to pyrethroids. Our study indicated that there was no difference in glucuronyltransferase activity of PBacid between humans and rats, and that only UGT1A9 can catalyze the glucuronidation of PBacid among human UGTs. Some UGT1A9 variants are known to have poor glucuronidation activity. From these results, it was assumed that deficiency or polymorphism of UGT1A9 might affect the profile of PBacid and its conjugates in urine collected from persons exposed to trans-permethrin or other pyrethroids. These results are helpful for understanding the metabolism of trans-permethrin in humans and determining methods for quantification of target analytes for assessment of human exposure to trans-permethrin and other pyrethroids that give PBacid and its conjugates as urinary metabolites.

High doses of Metofluthrin (MTF) have been shown to produce liver tumours in rats by a mode of action (MOA) involving activation of the constitutive androstane receptor leading to liver hypertrophy, induction of cytochrome P450 (CYP) forms and increased cell proliferation. The aim of this study was to compare the effects of MTF with those of the known rodent liver tumour promoter phenobarbital (PB) on the induction CYP2B forms and replicative DNA synthesis in cultured rat and human hepatocytes. Treatment with 50 microM MTF and 50 microM PB for 72 h increased CYP2B1 mRNA levels in male Wistar rat hepatocytes and CYP2B6 mRNA levels in human hepatocytes. Replicative DNA synthesis was determined by incorporation of 5-bromo-2'-deoxyuridine over the last 24 h of a 48 h treatment period. Treatment with 10-1000 microM MTF and 100-500 microM PB resulted in significant increases in replicative DNA synthesis in rat hepatocytes. While replicative DNA synthesis was increased in human hepatocytes treated with 5-50 ng/ml epidermal growth factor or 5-100 ng/ml hepatocyte growth factor, treatment with MTF and PB had no effect. These results demonstrate that while both MTF and PB induce CYP2B forms in both species, MTF and PB only induced replicative DNA synthesis in rat and not in human hepatocytes. These results provide further evidence that the MOA for MTF-induced rat liver tumour formation is similar to that of PB and some other non-genotoxic CYP2B form inducers and that the key event of increased cell proliferation would not occur in human liver.

The metabolites of tebufenozide, a model compound, formed by the yeast-expressed human CYP3A4 and CYP2C19 were identified to clarify the substrate recognition mechanism of the human cytochrome P450 (CYP) isozymes. We then determined whether tebufenozide metabolites may be predicted in silico. Hydrogen abstraction energies were calculated with the density functional theory method B3LYP/6-31G(∗). A docking simulation was performed using FRED software. Several alkyl sites of tebufenozide were hydroxylated by CYP3A4 whereas only one site was modified by CYP2C19. The accessibility of each site of tebufenozide to the reaction center of CYP enzymes and the susceptibility of each hydrogen atom for metabolism by CYP enzymes were evaluated by a docking simulation and hydrogen abstraction energy estimation, respectively.

(+)-Methyl [2-[(2R,3aS,4R,5R,6aS)-octahydro-5-hydroxy-4-[(E)-(3S,5S)-3-hydroxy-5-methyl-1-[3- 14 C]nonenyl]-2-pentalenyl]ethoxy]-acetate ([nonenyl-3- 14 C]SM-10902) (1) was labeled with carbon-14 for use in mammalian metabolic studies. The synthesis was achieved in 7 steps from [ 14 C]carbon dioxide: including : 1) Grignard reaction, 2) esterification, 3) condensation with dimethyl methylphosphonate, 4) Wittig-Horner reaction, 5) separation of isomers by HPLC. Stereoselective reduction of the protected ketone with sodium borohydride in the presence of cerium (III) chloride and subsequent desilylation produced 1. The overall yield was 11.1% from Ba[ 14 C]CO 3

(2S,3R)-2-[3-(4-Fluorophenyl)]propylamino-3-(3,4-dihydroxyphenyl)-3-hydroxypropionic acid pyrrolidine amide hydrobromide (SM-11044) was labeled with carbon-14 for use in mammalian metabolic studies. The synthesis was achieved according to the scheme shown in Fig. 5. Grignard reaction of 3,4-methylenedioxy-phenylmagnesium bromide with [14C]carbon dioxide liberated from barium [14C]carbonate ((UNDERLINE)6(/UNDERLINE)) gave the acid ((UNDERLINE)5(/UNDERLINE)). Reduction of (UNDERLINE)5(/UNDERLINE) with lithium aluminum hydride followed by oxidation of the resulting benzyl alcohol ((UNDERLINE)11(/UNDERLINE)) with chromium oxide-pyridine complex afforded the aldehyde ((UNDERLINE)3(/UNDERLINE)). Condensation of (UNDERLINE)3(/UNDERLINE) with the optically active (R)-oxazolidinone ((UNDERLINE)10(/UNDERLINE)) yielded the alcohol ((UNDERLINE)12(/UNDERLINE)). Catalytic hydrogenation of (UNDERLINE)12(/UNDERLINE) and subsequent hydrolysis produced the optically active β-hydroxy-α-amino acid ((UNDERLINE)2(/UNDERLINE)), which was treated with N-carbomethoxyphthalimide to give the hydroxy acid ((UNDERLINE)13(/UNDERLINE)). Reaction of (UNDERLINE)13(/UNDERLINE) with pivaloyl chloride gave the corresponding mixed anhydride, which was allowed to react with pyrrolidine to provide the amide ((UNDERLINE)14(/UNDERLINE)). Deprotection of (UNDERLINE)14(/UNDERLINE) with hydrazine hydrate afforded the hydroxyamide (15). Condensation of (UNDERLINE)15(/UNDERLINE) with the aldehyde ((UNDERLINE)16(/UNDERLINE)) and subsequent reduction of the resulting imine with sodium cyanoborohydride produced the fluoride ((UNDERLINE)17(/UNDERLINE)). Cleavage of the methylenedioxy group of (UNDERLINE)17(/UNDERLINE) gave the free base of (UNDERLINE)1(/UNDERLINE), which was treated with hydrobromic acid to afford (UNDERLINE)1(/UNDERLINE). The overall yield was 11.1% from (UNDERLINE)6(/UNDERLINE).

We have previously reported the discovery of a new class of potent inhibitors of 17β-hydroxysteroid dehydrogenase type 3 (17β-HSD3) derived from benzylidene oxazolidinedione and thiazolidinedione scaffolds. In this study, these analogs were designed, synthesized, and evaluated in a human cell-based assay. The detailed structure-activity relationship (SAR) surrounding this pharmacophore were developed, and consequently a number of compounds from this series demonstrated single-digit nanomolar 17β-HDS3 inhibitory activity in vitro. Subsequent optimization work in pursuit of the improvement of oral bioavailability demonstrated in vivo proof-of-concept by prodrug strategy based on phosphate esters for these 17β-HSD3 inhibitors. When a phosphate ester 16 was administered orally at a high dose of 100mg/kg, 16 showed approximately two times more potent testosterone (T)-lowering effect against a positive control in the luteinizing hormone-releasing hormone (LH-RH)-induced T production assay. The T-lowering effect continued at ca 10% level of control over 4h after administration. The nonsteroidal molecules based on this series have the potential to provide unique and effective clinical opportunities for treatment of prostate cancer.

Novel and potent inhibitors of 17β-hydroxysteroid dehydrogenase type 3 (17β-HSD3) were identified based on oxazolidinedione and thiazolidinedione derivatives, starting from a high-throughput screening hit, 5-(3-bromo-4-hydroxybenzyl)-3-(4-methoxyphenyl)-1,3-thiazol-2-one 1. 5-(3-Bromo-4-hydroxybenzylidene)-3-(4-methoxyphenyl)-2-thioxo-1,3-thiazolidin-4-one 21 exhibited a promising activity profile and demonstrated significant selectivity over the related 17β-HSD isoenzymes and nuclear receptors.

9-Amino-8-fluoro-2, 4-methano-1,2,3,4-tetrahydroacridine citrate (SM-10888), a novel cholinesterase inhibitor, was labeled with carbon-14 at C9 of the tetrahydroacridine ring for use in metabolic studies. Carbonation of 2,6-difluorophenyllithium (3) with [14C]carbon dioxide gave the acid (4). Chlorination of 4 followed by treatment of the resulting acid chloride with ammonia afforded the amide (5). Dehydration of 5 with thionyl chloride and subsequent displacement reaction with ammonia gave the aminobenzonitrile (7). Condensation of 7 with the ketone (8) in the presence of anhydrous zinc chloride yielded the aminoacridine (9), which was treated with citric acid to afford [9-14C]SM-10888 (1). The overall yield of 1 was 37% from 2, and the specific activity was 1.35 GBq/mmol.

N-[4-[4-(2-Pyrimidinyl)-1-piperazinyl]butyl]bicyclo-[2.2.1]heptane-2,3-di-exo-carboxyimide dihydrogen citrate (tandospirone), a novel anxiolytic agent, was labeled with carbon-14 individually at the imido carbonyl group and the pyrimidinyl ring. The synthesis of carbonyl-labeled tandospirone was achieved according to the scheme shown in Fig. 3. Diels-Alder reaction of maleic anhydride (2) with cyclopentadiene (3) afforded the endo anhydride (4), which was transformed into the imide (5) by treating with ammonia water. Thermal isomerization of the endo imide (5) and subsequent chromatographic separation gave the pure exo compound (6). Catalytic hydrogenation of 6 followed by alkylation with 1,4-dibromobutane (8) yielded the bromide (9a). Condensation of 9a with N-(2-pyrimidinyl)piperazine (10a) followed by treatment of the resulting disubstituted piperazine (11a) with citric acid afforded [carbonyl-14C]tandospirone (1a). The overall yield of 1a was 22% from 2. The similar method was applied to the synthesis of pyrimidinyl-labeled tandospirone as shown in Fig. 4. Condensation of 2-chloro[2-14C]pyrimidine (12) with anhydrous piperazine gave the pyrimidinylpiperazine (10b). N-alkylation of 10b followed by treatment with citric acid afforded [pyrimidinyl-2-14C]tandospirone (1b). The overall yield of 1b was 68% from 12.

(2R, 5S) - (+) -cis-3, 5-Dimethyl-2- (3-pyridyl) thiazolidin-4-one hydrochloride (SM 12502), a new PAF antagonist, was labeled with carbon-14 at C 2 of the thiazolidinone ring for use in metabolic studies. The synthesis was achieved according to the scheme illustrated in Fig, 3. 14C-Carbonation of 3-pyridyllithium (3) followed by chlorination and esterification gave mehyl [carbonyl-14C] nicotinate (6) . Reduction of 6 with diisobutylaluminium hydride produced a mixture of the alcohol (7) and the aldehyde (8) . Oxidation of the mixture with manganese dioxide gave 8 as a sole product. Condensation of 8 with methylamine and subsequent cyclocondensation of the imine (9) with (S) -2-mercaptopropionic acid (10) yielded a cis and trans mixture of the thiazolidinone (11) . Isolation of the desired stereoisomer by chiralphase HPLC and subsequent treatment with hydrochloric acid afforded 1. The overall yield of 1 was 22% from 2.

Two-year treatment with high doses of Metofluthrin produced hepatocellular tumors in both sexes of Wistar rats. To understand the mode of action (MOA) by which the tumors are produced, a series of studies examined the effects of Metofluthrin on hepatic microsomal cytochrome P450 (CYP) content, hepatocellular proliferation, hepatic gap junctional intercellular communication (GJIC), oxidative stress and apoptosis was conducted after one or two weeks of treatment. The global gene expression profile indicated that most genes with upregulated expression with Metofluthrin were metabolic enzymes that were also upregulated with phenobarbital. Metofluthrin induced CYP2B and increased liver weights associated with centrilobular hepatocyte hypertrophy (increased smooth endoplasmic reticulum [SER]), and induction of increased hepatocellular DNA replication. CYP2B1 mRNA induction by Metofluthrin was not observed in CAR knockdown rat hepatocytes using the RNA interference technique, demonstrating that Metofluthrin induces CYP2B1 through CAR activation. Metofluthrin also suppressed hepatic GJIC and induced oxidative stress and increased antioxidant enzymes, but showed no alteration in apoptosis. The above parameters related to the key events in Metofluthrin-induced liver tumors were observed at or below tumorigenic dose levels. All of these effects were reversible upon cessation of treatment. Metofluthrin did not cause cytotoxicity or peroxisome proliferation. Thus, it is highly likely that the MOA for Metofluthrin-induced liver tumors in rats is through CYP induction and increased hepatocyte proliferation, similar to that seen for phenobarbital. Based on analysis with the International Life Sciences Institute/Risk Science Institute MOA framework, it is reasonable to conclude that Metofluthrin will not have any hepatocarcinogenic activity in humans, at least at expected levels of exposure.

(1R,5S,6S)-2- [(3S,5S)-5-Dimethylaminocarbonylpyrrolidin-3-ylthio]-6- [(1R)-1-hydroxyethyl]-1-methylcarbapen-2-em-3-carboxylic acid trihydrate (SM-7338), a novel 1 β-methyl carbapenem antibiotic, was labeled with carbon-14 at the C3 position of the carbapenem nucleus for use in metabolic studies. The synthesis was achieved according to the scheme illustrated in Fig. 3. Selective esterification of [2-14C]malonic acid (2) with 4-nitrobenzyl bromide (3) gave its monoester (4). Condensation of the magnesium salt of 4 with the imidazolide derived from the azetidinone carboxylic acid (5) provided the β-keto ester (6), which was desililated with hydrochloric acid to give the alcohol (7). Treatment of 7 with carboxybenzenesulfonyl azide followed by decomposition of the resulting diazo intermediate (8) in the presence of a rhodium catalyst produced the bicyclic keto ester (9). Reaction of 9 with diphenyl chlorophosphate in the presence of N,N-diisopropylethylamine and subsequent displacement reaction of the vinyl phosphate (10) with mercaptopyrrolidine (11) gave bis-protected SM-7338 (12). Catalytic hydrogenolysis of 12 afforded [carbapenem-3-14C]-SM-7338 (1). The overall yield of 1 was 5.8% from 2.

Two stereoisomers of empenthrin, (E) -1-ethynyl-2-methyl-2-pentenyl (1 R) -cis, trans-chrysanthemates, were regioselectively labeled with carbon-14 for use in metabolic studies on the characteristic ethynyl alcohol moiety. Action of ethyl [14C] formate (2) on ethylidenetri-phenylphosphorane gave the 14C-formylated phosphorane (3) . Wittig reaction of 3 with propanal stereoselectively yielded the E isomer of 2-methyl-2- [1-14C] pentenal (4), which was derivatized to a crystalline imidazolidine (5) for purification. Regeneration of 4 from purified 5 followed by reaction with ethynylmagensium bromide gave (E) -1-ethynyl-2-methyl-2- [1-14C] -pentenol (6), the a-ethynyl alcohol of 14C-labeled empenthrin, in 36% overall radiochemical yield from 2. Esterification of 6 with (1R) -cis- and (1R) -traps-chrysanthemoyl chlorides afforded the corresponding optically active [pentenyl-1-14C] empenthrins (1a and 1b) in good yields after chromatographic purification.

The compounds bearing a butatriene linkage between bisdehydro[13]annulene and electron donating and withdrawing systems have been synthesized. The contribution of a dipolar structure in these compounds is discussed on the basis of the spectral data.

Synthesis of three 2,3-diiodo-1,3-dienes and conversion of these dienes into butatrienes are described. 2,5-Dimethylhexa-2,3,4-triene polymerizes on exposure to air to give the polymeric peroxide (C6H12O2)n which is reassigned as the structure containing acetylene and peroxide units.

Farnesylacetic acid was efficiently labelled with 14C at the 5-position and gefarnate, a potent ulcer inhibitor, was prepared from it in radioactive form for use in metabolic studies. Condensation of [carbonyl-14C]acetyl chloride (5) with t-butyl 2-ethoxymagnesiomalonate (6) followed by acid-catalyzed deprotection and decarboxylation gave ethyl 3-oxo[3-14C]butanoate (8). Alkylation of the keto ester (8) with geranyl bromide (9) afforded the unsaturated keto ester (10), which was hydrolyzed and decarboxylated to give geranyl[2-14C]acetone (11). Grignard reaction of 11 with cyclopropylmagnesium bromide followed by treatment with hydrobromic acid yielded [4-14C]homofarnesyl bromide (13). Cyanation of 13 with potassium cyanide and subsequent hydrolysis gave [5-14C]farnesylacetic acid (1) in 6.1% yield from barium [14C]carbonate (3). Chlorination of 1 followed by esterification with geraniol afforded [5-14C]gefarnate (2) in 88% yield.

Bromobutide, a novel herbicide, was labeled with carbon-14 independently at the carbonyl group and the phenyl ring for use in metabolic studies. 14C-Carbonation of neopentylmagnesium chloride (3) gave 3,3-dimethyl[1-14C]butyric acid (4a) quantitatively. Chlorination of 4a with thionyl chloride followed by alpha-bromination with bromine yielded 2-bromo-3,3-dimethyl[1-14C]-butyryl halide (5a), which was subsequently condensed with alpha, alpha-dimethylbenzylamine (6a) to afford [carbonyl-14C]bromobutide (1a). The overall yield of 1a was 76% from barium [14C]-carbonate (2). Similarly, condensation of alpha, alpha-dimethyl[phenyl-14C]benzylamine (6b), which was prepared from alpha-methyl[phenyl-U-14C]styrene (7) in three steps, with 2-bromo-3,3-dimethylbutyryl halide (5b) gave [phenyl-14C]bromobutide (1b) in 67% yield after purification. The specific activities of 1a and 1b were 1.38 and 0.781 GBq/mmol (37.2 and 21.1 mCi/mmol), respectively.