Global gene expression analysis of malignant lymphomas developed in mice exposed to continuous low-dose-rate gamma-ray

Abstract

Our previous reports (Radiat. Res. 160: 376, 2003, & 167: 417, 2007) indicate that the life shortening due to early neoplastic death was observed in B6C3F1 mice after long-term, continuous irradiation with low-dose-rate (21 mGy/day) and high dose (8000 mGy) gamma-ray. Although many of neoplasms from irradiated mice were malignant lymphomas, their incidences were not different from those of non-irradiated mice. In this study, we investigated the global gene expression between 20 malignant lymphomas from irradiated mice (RL) and 20 from non-irradiated controls (CL). Comparative microarray analysis using Agilent 44k microarray identified 418 up-regulated genes and 406 down-regulated genes in RL as compared with CL. The Gene Ontology classifications of the up-regulated genes in RL were shown significant enrichment to "immune response" or "positive regulation of cell proliferation", while the down-regulated genes in RL were significantly enriched to "cell cycle" or "apoptosis". These results indicate a possibility that the different genes are associated with development of RL and CL. This study was performed under the contract with the Aomori Prefectural Government, Japan.