ABSTRACT
In this study, the Whole Human Genome 44K DNA microarray assay was used for the first time to obtain gene expression profiles in human peripheral blood lymphocytes 2 h after exposure (in suspension) to 6.78 MeV mean energy alpha particles from extracellular (211)At. Lymphocytes were exposed to fluences of 0.3-9.6 x 10(6) alpha particles/cm(2) [corresponding to mean absorbed alpha-particle doses (D(alpha)) of 0.05-1.60 Gy] over 30 min. Significantly modulated expression was identified in 338 early-response genes. Up-regulated expression was evident in 183 early-response genes, while the remaining 155 were down-regulated. Over half of the up-regulated genes and 40% of the down-regulated genes had a known biological process related primarily to cell growth and maintenance and cell communication. Genes associated with cell death were found only in the up-regulated genes and those with development only in the down-regulated genes. Eight selected early-response genes that displayed a sustained up- or down-regulation (CD36, HSPA2, MS4A6A, NFIL3, IL1F9, IRX5, RASL11B and SULT1B1) were further validated in alpha-particle-irradiated lymphocytes of two human individuals using the TaqMan(R) RT-qPCR technique. The results confirmed the observed microarray gene expression patterns. The expression modulation profiles of IL1F9, IRX5, RASL11B and SULT1B1 genes demonstrated similar trends in the two individuals studied. However, no significant linear correlation between increasing relative gene expression and the alpha-particle dose was evident. The results suggest the possibility that a panel of genes that react to alpha-particle radiation does exist and that they merit further study in a greater number of individuals to determine their possible value regarding alpha-particle biodosimetry.
Subject(s)
Astatine/pharmacology , Gene Expression Profiling , Lymphocytes/radiation effects , Adult , Aged , Alpha Particles/adverse effects , Female , Gene Expression Regulation/radiation effects , Genes/radiation effects , Humans , Male , Oligonucleotide Array Sequence Analysis/methods , RNA/isolation & purification , Reverse Transcriptase Polymerase Chain Reaction/methodsABSTRACT
PURPOSE: Identification of early radiation response genes (ERG) in human lymphocytes after gamma-irradiation by using the whole-human-genome DNA-microarrays and the evaluation of their possible role in rapid radiation biodosimetry by applying real-time quantitative polymerase chain reaction (RT-qPCR) methodology for validation in a small group of human individuals. MATERIALS AND METHODS: Whole blood from a healthy human donor was exposed at 37 degrees C to 137Cs gamma-radiations (absorbed dose: 1-4 Gy). Fifteen minutes following irradiation the lymphocytes were isolated from the blood (for 2 h at 20 degrees C) and their gene expression was investigated using the DNA-microarrays. Subsequently, 14 genes were selected and validated using the TaqMan probes based upon the RT-qPCR assay within a group of 6 human donors. RESULTS: A dose-related relative change in quantitative gene expression using the DNA-microarray assay was demonstrated in 24 of 102 genes. Up-regulation of expression was observed in 15 genes: CD69 (CD69 molecule), CDKN1A (cyclin-dependent kinase inhibitor 1A), EGR1 (early growth response 1), EGR4 (early growth response 4), FLJ35725 (chromosome 4 ORF 23), hCG2041177 (hCG - human Celera Genome), hCG1643466.2, IFN-gamma (interferon-gamma), ISG20L (interferon stimulated exonuclease gene 20 kDa - like 1), c-JUN (jun oncogene), MDM2 (mouse double minute 2), MUC5B (mucine), PLK2 (polo-like kinase 2), RND1 (rho-family GTPase 1) and TNFSF9 (tumour necrosis factor superfamily member 9). Down-regulation of expression was found in the remaining nine genes: GRIK3 (glutamate receptor ionotropic kainate 3), hCG1985174, hCG1998530, hCG2038519, OCLN (occludin), RPL10A (ribosomal protein L10a), SERHL2 (serine hydrolase-like 2), SGK3 (serum/glucocorticoid regulated kinase 3) and STARD13 (START domain containing 13). CONCLUSION: A significant correlation between absorbed radiation dose and change in relative gene expression was particularly evident for EGR1, EGR4, IFN-gamma, c-JUN and TNFSF9 (p < or = 0.05). Results warrant the further investigation of these ERG as potential biodosimetric markers.
