Carcinogenesis by carbamic acid esters and their binding to DNA

Area of Science:

• Toxicology
• Carcinogenesis
• Molecular Biology

Background:

• Carbamates are a class of chemical compounds with diverse applications, some of which have demonstrated carcinogenic potential.
• Understanding the relationship between chemical structure, DNA binding, and tumor initiation is crucial for risk assessment.

Purpose of the Study:

• To evaluate the tumor-initiating potency of simple alkyl carbamates and mono-N-substituted ethyl carbamates.
• To investigate the DNA binding characteristics of these carbamates in various organs.
• To assess the influence of croton oil as a co-carcinogen on tumor development and DNA binding.

Main Methods:

• Tumorigenicity was assessed in Hall strain mice exposed to different carbamates.
• The binding of 14C-labeled carbamates to DNA was quantified in Crackenbush mice.
• The effect of a preliminary croton oil application on tumor yield and DNA binding was examined.

Main Results:

• Ethyl carbamate exhibited the highest carcinogenicity for epidermis, liver, and lung, followed by its N-alkyl derivatives.
• Methyl carbamate showed no carcinogenic effect, while n-propyl and n-butyl carbamates were potential carcinogens.
• Ethyl carbamate esters demonstrated greater and more persistent DNA binding in liver and skin compared to other alkyl esters.
• Croton oil application increased skin tumor yield and carbamate-DNA binding, particularly with ethyl carbamate.

Conclusions:

• Ethyl carbamate is a potent carcinogen, with its tumor-initiating and DNA-binding activities being organ-specific and influenced by chemical structure.
• The observed enhancement of carbamate carcinogenicity and DNA binding by croton oil suggests a co-carcinogenic role.
• These findings contribute to understanding the mechanisms of chemical carcinogenesis and the role of DNA adducts.