Development of Gene Expression Fingerprints for Identification of Environmental Contaminants Using cDNA Arrays

摘要

This technical note reports the current status of work being done at the U.S. Army Engineer Research and Development Center (ERDC) to develop cDNA array-based assays that map gene expression from contaminant exposures. Results substantiate that distinct gene expression profiles exist for major contaminant classes such as PARs, PCBs, and PCDD/Fs. Results also indicate that identification of these contaminant mixtures in environmental media is possible by examining their effects on gene expression in mammalian cells. Research at ERDC directed at developing screening assays for contaminated sediments has been applied to extracts of both sediments and the organisms living in them. Several microbial and cell-based in vitro methods are now routinely used for this purpose. These were described, and the possibilities of using cDNA arrays in a screening assay were explored, in a preceding Technical Note (TN-DOER-Cl9, Inouye and McFarland (2001)). Briefly, cDNA arrays allow quantification of gene expression profiles (genes that are 'turned on or off' at a selected time) providing a 'fingerprint' of the sub-cellular responses of the test subject, e. g., cultured human liver cells, to a chemical challenge. While current in vitro tests such as the 101L cell-based assay for dioxin equivalents (TN-DOER-ClO, Ang et al. (2000)) offer inexpensive and rapid screening of one endpoint, cDNA arrays offer the potential for simultaneous screening of multiple endpoints and mixtures of contaminants. The activation of multiple genes related to disruption of normal cell functions, such as apoptosis, tumor suppression, cell proliferation, cell cycles, cytokines, oxidative stress, and more, can be measured in a single exposure using eDNA arrays. The resulting information can provide valuable insights into the toxic modes of action (MOAs) of mixtures of contaminants present in sediments.