title: Characterization and interlaboratory comparison of a gene expression signature for differentiating genotoxic mechanisms.
abstract: 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.
authors.affiliation: Bayer HealthCare AG, Special Toxicology, 42096 Wuppertal, Germany.
authors.forename: Heidrun
authors.initials: H
authors.lastname: Ellinger-Ziegelbauer
authors.forename: Jennifer M
authors.initials: JM
authors.lastname: Fostel
authors.forename: Chinami
authors.initials: C
authors.lastname: Aruga
authors.forename: Daniel
authors.initials: D
authors.lastname: Bauer
authors.forename: Eric
authors.initials: E
authors.lastname: Boitier
authors.forename: Shibing
authors.initials: S
authors.lastname: Deng
authors.forename: Donna
authors.initials: D
authors.lastname: Dickinson
authors.forename: Anne-Celine
authors.initials: AC
authors.lastname: Le Fevre
authors.forename: Albert J
authors.initials: AJ
authors.lastname: Fornace
authors.forename: Olivier
authors.initials: O
authors.lastname: Grenet
authors.forename: Yizhong
authors.initials: Y
authors.lastname: Gu
authors.forename: Jean-Christophe
authors.initials: JC
authors.lastname: Hoflack
authors.forename: Masako
authors.initials: M
authors.lastname: Shiiyama
authors.forename: Roger
authors.initials: R
authors.lastname: Smith
authors.forename: Ronald D
authors.initials: RD
authors.lastname: Snyder
authors.forename: Catherine
authors.initials: C
authors.lastname: Spire
authors.forename: Gotaro
authors.initials: G
authors.lastname: Tanaka
authors.forename: Jiri
authors.initials: J
authors.lastname: Aubrecht
mesh_terms: D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002869:Chromosome Aberrations / Q000139:chemically induced; D002945:Cisplatin / Q000633:toxicity; D016000:Cluster Analysis; D018736:DNA Adducts / Q000378:metabolism; D053903:DNA Breaks, Double-Stranded; D004249:DNA Damage; D004305:Dose-Response Relationship, Drug; D005047:Etoposide / Q000633:toxicity; D020869:Gene Expression Profiling / Q000592:standards; D005786:Gene Expression Regulation / Q000187:drug effects*; D006801:Humans; D007753:Laboratories / Q000592:standards; D009152:Mutagenicity Tests / Q000379:methods* / Q000592:standards; D009153:Mutagens / Q000633:toxicity*; D015588:Observer Variation; D017239:Paclitaxel / Q000633:toxicity; D016133:Polymerase Chain Reaction / Q000592:standards; D015203:Reproducibility of Results; D018570:Risk Assessment; D012965:Sodium Chloride / Q000633:toxicity; D008941:Spindle Apparatus / Q000187:drug effects; D013997:Time Factors
chemical_list: D018736:DNA Adducts; D009153:Mutagens; D012965:Sodium Chloride; D005047:Etoposide; D017239:Paclitaxel; D002945:Cisplatin