Assessment of the in vitro γH2AX assay by High Content Screening as a novel genotoxicity test

The gamma H2AX assay is widely used as a marker of DNA damage in multiple scientific fields such as cancer biomarker, clinical studies and radiation biology. In particular, the in vitro gamma H2AX assay has been suggested as a novel in vitro genotoxicity test with potential as a pre-screening tool. However, to date, limited assessments have been carried out to evaluate the sensitivity, specificity and accuracy of the in vitro gamma H2AX assay. In this study, the microscopy-based system combining automated cellular image acquisition with software quantification for High Content Screening (HCS) has been used for the first time to evaluate the in vitro gamma H2AX assay. A panel of well-characterised genotoxic and non-genotoxic compounds was selected to assess the performance of the in vitro gamma H2AX assay in the human bronchial epithelial cell line BEAS-2B. The results obtained during this preliminary assessment indicate that the in vitro gamma H2AX assay has a high accuracy (86%) as a result of high sensitivity and specificity (86-92% and 80-88% respectively). Our data highlight the potential for gamma H2AX detection in HCS as a complement to the current regulatory genotoxicity battery of in vitro assays. We therefore recommend more comprehensive assessments to confirm the performance of the in vitro gamma H2AX assay by HCS with a more extensive set of compounds. (C) 2013 The Authors. Published by Elsevier B.V. All rights reserved.