Search results for "Nitroreductases"
showing 5 items of 5 documents
Analysis of metabolism and genotoxicity of 5-nitro-3-thiophenecarboxanilides in bacterial, mammalian and human cells
1995
5-nitro-3-thiophenecarboxanilide (NTCA3) was clearly mutagenic in Salmonella typhimurium strains TA98, YG1021 (the strain with elevated nitroreductase) and YG1024 (the strain with elevated O-acetyltransferase) and only slightly mutagenic at the gpt locus in AS52 cells. Clastogenic activity in human lymphocytes was dependent on the length of exposure : detectable chromosome aberrations were observed following a 24 h treatment period, but not after 3 h exposure. S9 increased genotoxicity in both mammalian cells and human lymphocytes. Metabolites formed by incubation of NTCA3 with the different cell systems were examined. A time-course study in cell whole extracts showed that bacterial and mam…
A nitroreductase and glutathione responsive nanoplatform for integration of gene delivery and near-infrared fluorescence imaging
2020
A novel platform rationally integrating indocyanine green analogues and an arginine-rich dendritic peptide with both nitroreductase (NTR) and glutathione (GSH) reduction responsive linkers was developed. This multifunctional platform can enable selective and efficient gene delivery and specific turn-on fluorescence imaging in tumors.
Distribution of nitroreductive activity toward nilutamide in rat.
2004
Abstract Nilutamide is a pneumotoxic and hepatotoxic nitroaromatic (R-NO 2 ) antiandrogen used in the treatment of prostate carcinoma in man. Previously, we established that in the rat lung, the drug is metabolized into the corresponding hydroxylamine (R-NHOH) and amine (R-NH 2 ) derivatives. These results evidenced a cytosolic oxygen-sensitive (type II) nitroreductase activity in lung. In the present studies, we extended the characterization of nilutamide metabolism in liver, brain, kidney, heart, blood, intestine (small, cecum, and large, and their respective luminal contents) of male Sprague–Dawley rats. Subcellular fractions for all tissues (except blood) examined (postmitochondrial, cy…
Influence of nitroreductase and O-acetyltransferase on the mutagenicity of substituted nitrobenzothiophenamines in Salmonella typhimurium.
1999
The mutagenic activity of 17 substituted (aryl)(2-nitrobenzo[b]thiophen-3yl)amines has been evaluated in the Ames test with different isogenic strains of Salmonella typhimurium, that varied in their expression of nitroreductase and O-acetyltransferase. Active derivatives induced frameshift mutations in TA98 strain, and differences in the chemical structure resulted in up to 15-fold changes in mutagenic activity. The non-mutagenic compounds are the unsubstituted parent compound and derivatives with para-chloro, para-fluoro, para-diethylamino, meta-bromo and para-dimethylamino groups. They do not show any activity even in strains with higher level of nitroreductase or O-acetyltransferase. The…
Mechanism of genotoxicity and electron density distribution by NMR of 5-nitro-3-thiophenecarboxamides, a novel group of direct-acting mutagens in Sal…
1993
Abstract The mutagenic activity of 23 5-nitro-3-thiophenecarboxanilides and of 5-nitro-3-thiophenecarboxamide, the prototype, (NTCAs) have been evaluated in the Ames test on Salmonella typhimurium strains TA100 ad TA98 with and without metabolic activation. Effects of different substituents (electron-donating and electron-withdrawing) were studied to evaluate structural features that affect the metabolism and the bacterial mutagenic potency. All the derivatives were direct-acting mutagens, the mutagenic potency ranging from 0.7 to 142 revertants (rev.)/nmol in TA100 and from 0.09 to 68 rev./nmol in TA98 strain. Results obtained with strains TA98NR and TA98/1,8-DNP 6 indicated that the mutag…