AM_GeneExpressionAfterIonisingRadiation

Abstract Purpose: There is a recognised need to develop new methods of high throughput, rapid and minimally invasive individual dose assessment for radiation exposure. The aim of this work is to establish a panel of highly radiation responsive genes suitable for biological dosimetry and to explore inter-individual variation in response to ionising radiation exposure.Materials and method: Analysis of gene expression in response to radiation was carried out using three independent techniques (microarray, Multiplex Quantitative RT-PCR and nCounter Analysis System) in human lymphocytes in culture and circulating blood exposed ex vivo from the same donors. Results: Variations in transcriptional response to exposure to ionising radiation analysed by microarray allowed the identification of genes which can be validated and measured accurately as biomarkers of radiation exposure using other techniques. We have identified genes which are consistently up-regulated following exposure at different time points to either 2 or 4 Gy of X-rays, for all individuals in blood and cultured lymphocytes. Most down-regulated genes including cyclins, centromeric and mitotic checkpoints proteins, particularly those associated with chromosome instability and cancer can only be detected in dividing cells. Conclusions: The data provides evidence that there are a number of genes which seem suitable for biological dosimetry, like SESN1, GADD45A, CDKN1A, CCNG1, FDXR, BBC3 and MDM2. These biomarkers could potentially be used for triage after large-scale radiological incidents. Variations in transcriptional response accurately measured by MQRT-PCR may allow the identification of biomarkers of radiation sensitivity and individual susceptibility and therefore being useful in radiation oncology.