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In vitro system for detecting non-genotoxic carcinogens
S D Dertinger1, D K Torous, A M Tometsko
1Litron Laboratories, Rochester, New York 14620.
Environmental and Molecular Mutagenesis
|January 1, 1993
Summary
Identifying non-genotoxic carcinogens is challenging. This study shows that some carcinogens modulate drug metabolism enzymes, increasing mutagenic responses and contributing to cancer development.
Area of Science:
- Toxicology
- Biochemistry
- Carcinogenesis
Background:
- In vitro assays struggle to identify non-genotoxic carcinogens, limiting chemical risk assessment.
- A practical method for detecting non-genotoxic carcinogens remains elusive.
- Understanding mechanisms beyond direct DNA damage is crucial for carcinogen identification.
Purpose of the Study:
- To investigate if non-genotoxic carcinogens modulate enzymatic drug metabolism.
- To explore the role of enzyme modulation in chemical carcinogenesis.
- To identify a potential mechanism for non-genotoxic carcinogen action.
Main Methods:
- Utilized a modified Ames plate incorporation assay.
- Tested six known tumor promoters as model non-genotoxic carcinogens.
- Assessed enzyme-modulating effects using a mammalian metabolic activation system (S9).
Main Results:
- All tested non-genotoxic carcinogens significantly increased mutagenic responses.
- These chemicals altered the mutagenicity of promutagens in the presence of S9.
- Evidence suggests modulation of drug metabolism enzymes by carcinogens.
Conclusions:
- Some chemicals may cause cancer by altering drug metabolism pathways.
- Enzyme modulation by tumor promoters can increase cellular mutation rates.
- This mechanism contributes to neoplastic transformation and cancer development.