Carcinogenesis
August 2008
Elevated protein expression of inducible nitric oxide synthase (iNOS) has been observed in human pancreatic cancers and therefore, iNOS may play important roles in pancreatic carcinogenesis. This was examined in the present study, using an experimental model with N-nitrosobis(2-oxopropyl)amine (BOP)-treated hamsters. Reverse transcription-polymerase chain reaction analysis demonstrated iNOS expression in a hamster pancreatic cancer cell line as well as in human pancreatic cancer cell lines.
View Article and Find Full Text PDFIt is generally assumed that inflammation influences carcinogenesis. We previously reported that dextran sodium sulfate (DSS) strongly enhances colon carcinogenesis in the Apc(Min/+) mice and the over-expression of inducible nitric oxide synthase (iNOS) contributes to this enhancement. In the current study, we investigated the effect of a selective iNOS inhibitor, ONO-1714 on colitis-related colon carcinogenesis in the Apc(Min/+) mouse treated with DSS.
View Article and Find Full Text PDFThe expression of inducible nitric oxide synthase (iNOS) is markedly elevated in rat colon cancers induced by azoxymethane (AOM). In addition, iNOS can be detected in most adenomas and dysplastic aberrant crypt foci (ACF), suggesting that iNOS plays an important role in colon carcinogenesis. In the present study, the effect of an iNOS inhibitor, ONO-1714 ((1S,5S,6R,7R)-7-chloro-3-imino-5-methyl-2-azabicyclo[4.
View Article and Find Full Text PDFActivating mutations of K-ras are frequent in colon tumors and aberrant crypt foci, and may play important roles in colon carcinogenesis. Here, we investigated the effects of a K-ras codon 12 mutation on inducible nitric oxide synthase (iNOS) expression. When rat intestinal epithelial cells (IEC-6) were transfected with K-rasAsp12 cDNA, the iNOS expression linked to interleukin-1beta (IL-1beta) or lipopolysaccharide (LPS) treatment was markedly increased and prolonged.
View Article and Find Full Text PDFA series of 2-iminopiperidines fused to small-membered rings (Tables 1 and 2) were synthesised and biologically evaluated using an in vitro human nitric oxide synthase (NOS) inhibition assay. Fused bicyclic compounds 5-9 exhibited nearly the same potency as compound 1 in the hiNOS inhibition assay. Among these, the 1-methyl analogues 8 and 9 showed better isoform selectivity than their corresponding unsubstituted analogues 7 and 6, respectively.
View Article and Find Full Text PDFFurther chemical modification of 2-iminopiperidines fused to cyclopropane rings was performed. Optically active isomers 2 and 13 were synthesized and their biological activity was evaluated. Compound 2 exhibited greater potency and more isoform selectivity than enantiomer 13 in the iNOS inhibition assay.
View Article and Find Full Text PDFBioorg Med Chem
March 2003
The process of discovery and biological evaluation of alpha,beta-unsaturated cyclic amidines, as selective inhibitors of inducible nitric oxide synthase (iNOS), is reported. Dihydropyridin-2(1H)-imines and 1,5,6,7-tetrahydro-2H-azepin-2-imines were synthesized and biologically evaluated both in vitro and in vivo using a nitric oxide synthase inhibition assay. Compounds 1, 5, 6, 8-12 and 16 exhibited potent inhibition of iNOS.
View Article and Find Full Text PDFBioorg Med Chem Lett
September 2002
Dihydropyridin-2-imines were synthesized and biologically evaluated both in vitro and in vivo using a nitric oxide inhibition assay. Compounds 1, 4, 5 and 7-11 exhibited potent activity in the inducible nitric oxide (iNOS) inhibition assay. Of these 5, 6, 9 and 10 showed 5- to 11-fold increases in isoform selectivity.
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