Characterization and Interlaboratory Comparison of a Gene Expression Signature for Differentiating Genotoxic Mechanisms

• Published in: Toxicological sciences 2009-08, Vol.110 (2), p.341-352
• Main Authors: Ellinger-Ziegelbauer, Heidrun, Fostel, Jennifer M., Aruga, Chinami, Bauer, Daniel, Boitier, Eric, Deng, Shibing, Dickinson, Donna, Le Fevre, Anne-Celine, Fornace, Albert J., Grenet, Olivier, Gu, Yizhong, Hoflack, Jean-Christophe, Shiiyama, Masako, Smith, Roger, Snyder, Ronald D., Spire, Catherine, Tanaka, Gotaro, Aubrecht, Jiri
• Format: Article
• Language: English
• Subjects: Cell Line, Tumor; Cell Proliferation - drug effects; Cell Survival - drug effects; Chromosome Aberrations - chemically induced; Cisplatin - toxicity; Cluster Analysis; DNA Adducts - metabolism; DNA Breaks, Double-Stranded; DNA Damage; Dose-Response Relationship, Drug; Etoposide - toxicity; gene expression; Gene Expression Profiling - standards; Gene Expression Regulation - drug effects; Genetic Toxicology; Humans; Laboratories - standards; Mutagenicity Tests - methods; Mutagenicity Tests - standards; Mutagens - toxicity; Observer Variation; Paclitaxel - toxicity; Polymerase Chain Reaction - standards; Reproducibility of Results; Risk Assessment; Sodium Chloride - toxicity; Spindle Apparatus - drug effects; Time Factors
• ISSN: 1096-6080; 1096-0929
• DOI: 10.1093/toxsci/kfp103

The genotoxicity testing battery is highly sensitive for detection of chemical carcinogens. However, it features a low specificity and provides only limited mechanistic information required for risk assessment of positive findings. This is especially important in case of positive findings in the in vitro chromosome damage assays, because chromosome damage may be also induced secondarily to cell death. An increasing body of evidence indicates that toxicogenomic analysis of cellular stress responses provides an insight into mechanisms of action of genotoxicants. To evaluate the utility of such a toxicogenomic analysis we evaluated gene expression profiles of TK6 cells treated with four model genotoxic agents using a targeted high density real-time PCR approach in a multilaboratory project coordinated by the Health and Environmental Sciences Institute Committee on the Application of Genomics in Mechanism-based Risk Assessment. We show that this gene profiling technology produced reproducible data across laboratories allowing us to conclude that expression analysis of a relevant gene set is capable of distinguishing compounds that cause DNA adducts or double strand breaks from those that interfere with mitotic spindle function or that cause chromosome damage as a consequence of cytotoxicity. Furthermore, our data suggest that the gene expression profiles at early time points are most likely to provide information relevant to mechanisms of genotoxic damage and that larger gene expression arrays will likely provide richer information for differentiating molecular mechanisms of action of genotoxicants. Although more compounds need to be tested to identify a robust molecular signature, this study confirms the potential of toxicogenomic analysis for investigation of genotoxic mechanisms.