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Chromate-induced epimutations in mammalian cells
Catherine B Klein1, Lin Su, Darlene Bowser
1Nelson Institute of Environmental Medicine, New York University School of Medicine, 550 First Avenue, New York, NY 10016, USA. kleinc@env.med.nyu.edu
Environmental Health Perspectives
|November 12, 2002
Summary
Carcinogenic potassium chromate salts induce epigenetic gene silencing via DNA methylation in mammalian cells. In contrast, insoluble barium chromate caused mutations but not this specific epigenetic silencing.
Area of Science:
- Molecular Biology
- Epigenetics
- Toxicology
Background:
- Aberrant DNA methylation silences tumor suppressor genes, contributing to cancer.
- Mammalian cell lines with reporter genes allow studying carcinogen-induced gene inactivation.
- Previous studies identified nickel, diethylstilbestrol, and X-rays as inducers of epigenetic silencing.
Purpose of the Study:
- To investigate whether carcinogenic potassium chromate salts induce aberrant DNA methylation and gene silencing.
- To compare the effects of soluble potassium chromate with insoluble barium chromate on gene expression and DNA methylation.
Main Methods:
- Utilizing a transgenic V79-derived mammalian cell line (G12) containing a bacterial gpt reporter gene.
- Exposing the G12 cells to carcinogenic potassium chromate salts and insoluble barium chromate.
- Analyzing gene inactivation through both mutagenic and epigenetic DNA methylation mechanisms.
Main Results:
- Carcinogenic potassium chromate salts were found to induce aberrant DNA methylation, leading to gene silencing.
- Insoluble barium chromate induced significant mutations but did not cause DNA methylation changes associated with transgene expression.
- This study demonstrates potassium chromate as a novel inducer of epigenetic gene silencing.
Conclusions:
- Carcinogenic potassium chromate salts represent a new class of agents capable of inducing epigenetic gene silencing through DNA methylation.
- The findings highlight the distinct mechanisms by which different forms of chromate can affect cellular processes, with implications for understanding carcinogenicity.