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A General Method for Detecting Nitrosamide Formation in the In Vitro Metabolism of Nitrosamines by Cytochrome P450s
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Mutagenicity and cross-linking activity of chloroalkylnitrosamines, possible new antitumor lead compounds

S Ishikawa1, M Mochizuki

  • 1Kyoritsu College of Pharmacy, Shibakoen 1-5-30, Minato-ku, Tokyo 105-8512, Japan. ishikawa-st@kyoritsu-ph.ac.jp

Mutagenesis
|July 4, 2003
PubMed

Insights

Chlorinated nitrosamines are potent mutagens that damage bacterial DNA, with activity enhanced by a chloro group. Some analogs also exhibit DNA cross-linking, suggesting potential as bifunctional antitumor agents.

Area of Science:

  • Chemical mutagenesis and DNA damage mechanisms.
  • Structure-activity relationships in chemical carcinogenesis.
  • Development of novel antitumor agents.

Background:

  • Environmental nitrosamines are recognized as potential carcinogens.
  • The mutagenicity and DNA reactivity of chlorinated nitrosamines are not fully understood.
  • Understanding DNA repair pathways is crucial for assessing chemical toxicity.

Purpose of the Study:

  • To evaluate the mutagenicity of chlorinated alpha-acetoxy nitrosamines.
  • To elucidate the mechanism of DNA reaction and damage.
  • To explore the potential of these compounds as antitumor lead compounds.

Main Methods:

  • Bacterial mutagenicity assays using nine strains with varying DNA repair capabilities.
  • Comparison of mutagenicity between chlorinated and non-chlorinated nitrosamines.
  • Assessment of DNA cross-linking activity using plasmid DNA.

Main Results:

  • Chlorinated nitrosamines demonstrated direct mutagenicity across all tested bacterial strains.
  • Mutagenic activity was enhanced in ogt gene-deficient strains, indicating O(6)-alkylguanine adduct formation.
  • Chloropropyl and chlorobutyl nitrosamines induced interstrand DNA cross-links, similar to antitumor agents.

Conclusions:

  • Chlorinated nitrosamines possess significant mutagenic and DNA-damaging properties.
  • The chloro group enhances alkylating activity and contributes to DNA cross-linking.
  • These novel chlorinated nitrosamines show promise as bifunctional antitumor lead compounds.

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