抄録
To characterize gene expression profiles of neonatal human dermal fibroblast (NHDF) cells treated with X-ray or carbon-ion, we performed a genome-wide survey of the temporal transcriptional response of the cells using oligonucleotide microarrays. Total RNA was purified from NHDF cells at 1, 3, 6, 12, 18 and 24 hr after exposure to 0.1, 2 and 5 Gy. Based on array data derived from the X-ray and carbon-ion irradiations, X-ray: 977; carbon-ion: 966 genes with statistically significant differences in exposure dosage and time were isolated by ANOVA. Genes with expression changes of more than 1.5 fold were further analyzed, and their characteristic beam-specific profiles were respectively derived. Interestingly, majority of these genes were down regulated, and changes in the total expression level were higher with carbon-ion irradiation, with the time factor exerting a greater effect on gene expression variations than dosage. Another N-way ANOVA analysis was performed to select 510 genes, and further selection was made to find 70 genes that showed radiation species-dependent gene expression change (fold change>1.25). The genes were then categorized by the k-mean clustering method into 4 clusters; where they were found to display special features with regard to respective cell cycles, cell deaths, responses to stress and metabolisms. Identification and characterization of X-ray- or carbon ion-specific genes may facilitate an understanding of the molecular response mechanisms in the irradiated cells.
