Transcriptional changes in normal human liver cells exposed to tetrachloroethylene metabolite using microarray analysis.
Toxicologist 2003 Mar; 72(S-1):262-263
Trichloroacetic acid (TCA) is a major metabolite of tetrachloroethylene (TCE) in both humans and experimental animals. Occupational exposure to TCE can occur through inhalation, skin contact or ingestion during its use in dry cleaning and degreasing. TCE is converted to TCA mediated through cytochrome P450 pathway. Although TCE is classified as a probable carcinogen to humans by International Agency for Research on Cancer, inadequate evidence limits classifying TCA as a probable carcinogen. Studies have been conducted in our laboratory to determine whether exposure to TCA causes alterations in expression of cancer related genes in cultured human cells. Exponentially growing normal human liver cells were exposed to 200 and 400 uM concentration of TCA for 12h. Total RNA was used for the preparation of double standard cDNA. Biotin labeled cRNA transcript was synthesized using cDNA, fragmented and hybridized to HuGeneFL GeneChip probe arrays representing more than 6800 human genes and expressed sequence tags. The arrays were stained with streptavidin-phycoerythrin and biotinylated anti-streptavidin antibodies. The differential gene expression data analysis was performed using GeneChip 4.0 software. The 3'/5' cRNA transcript ratios for both GAPDH and bactin were found to be consistent between control and treatment groups over a period of 12h exposure. Altered gene expression patterns were observed in 133 RNA transcripts with at least a 2 fold change. Alterations in expression include metabolic genes (CYP11B1, MGMT), cell cycle control and DNA repair genes (GADD45, Cyclin G2, Cyclin D3, Cyclin A) and transcription factors (IF2, IF3). Whether alterations in the expression pattern of these genes, particularly transcriptional factors, is associated with carcinogenic potential of TCA needs to be elucidated.
Liver-cells; Exposure-levels; Metabolites; Occupational-exposure; Dry-cleaning-industry; Carcinogens; Animal-studies; Animals; Laboratory-animals; Genes
Research Tools and Approaches: Cancer Research Methods
The Toxicologist. Society of Toxicology 42nd Annual Meeting and ToxExpo, Cutting-Edge Science, Networking, New Perspectives, March 9-13, 2003, Salt Lake City, Utah