Related Experiment Videos
Induction of gene amplification by arsenic
1Laboratory of Molecular Carcinogenesis, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709.
Science (New York, N.Y.)
|July 1, 1988
Summary
Arsenic causes cancer in humans by inducing gene amplification, not mutations. This mechanism may explain why animal studies fail to detect arsenic
Area of Science:
- Environmental toxicology
- Molecular biology
- Carcinogenesis research
Background:
- Arsenic is a known human carcinogen with limited evidence in animal models.
- Its role in cancer initiation and promotion in standard animal models is unclear.
Purpose of the Study:
- To investigate the mechanism of arsenic-induced carcinogenicity.
- To explore the relationship between arsenic, gene amplification, and oncogenesis.
Main Methods:
- Exposure of 3T6 cells to sodium arsenite and sodium arsenate.
- Assessing methotrexate resistance as an indicator of gene amplification.
- Analyzing dihydrofolate reductase gene copy number.
Main Results:
- Arsenic salts induced high frequencies of methotrexate-resistant cells.
- Resistant cells exhibited amplified dihydrofolate reductase genes.
- Arsenic did not appear to induce gene mutations in this model.
Conclusions:
- Arsenic's carcinogenicity in humans may be linked to its ability to induce gene amplification.
- Gene amplification, rather than mutation, might be a key mechanism.
- Standard animal carcinogenicity tests may not detect agents acting late in the process.