Iwakawa Mayumi, Hamada Nobuyuki, Imadome Kaori, Funayama Tomoo, Sakashita Testuya, Kobayashi Yasuhiko, Imai Takashi
RadGenomics Research Group, Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, 4-9-1 Anagawa, Chiba, Japan.
Mutat Res. 2008 Jul 3;642(1-2):57-67. doi: 10.1016/j.mrfmmm.2008.04.007. Epub 2008 May 2.
Evidence has accumulated that ionizing radiation induces biological effects in non-irradiated bystander cells having received signals from directly irradiated cells; however, energetic heavy ion-induced bystander response is incompletely characterized. Here we performed microarray analysis of irradiated and bystander fibroblasts in confluent cultures. To see the effects in bystander cells, each of 1, 5 and 25 sites was targeted with 10 particles of carbon ions (18.3 MeV/u, 103 keV/microm) using microbeams, where particles traversed 0.00026, 0.0013 and 0.0066% of cells, respectively. diated cells, cultures were exposed to 10% survival dose (D), 0.1D and 0.01D of corresponding broadbeams (108 keV/microm). Irrespective of the target numbers (1, 5 or 25 sites) and the time (2 or 6h postirradiation), similar expression changes were observed in bystander cells. Among 874 probes that showed more than 1.5-fold changes in bystander cells, 25% were upregulated and the remainder downregulated. These included genes related to cell communication (PIK3C2A, GNA13, FN1, ANXA1 and IL1RAP), stress response (RAD23B, ATF4 and EIF2AK4) and cell cycle (MYCN, RBBP4 and NEUROG1). Pathway analysis revealed serial bystander activation of G protein/PI-3 kinase pathways. Instead, genes related to cell cycle or death (CDKN1A, GADD45A, NOTCH1 and BCL2L1), and cell communication (IL1B, TCF7 and ID1) were upregulated in irradiated cells, but not in bystander cells. Our results indicate different expression profiles in irradiated and bystander cells, and imply that intercellular signaling between irradiated and bystander cells activate intracellular signaling, leading to the transcriptional stress response in bystander cells.
越来越多的证据表明，电离辐射会在未受照射的旁观者细胞中诱导生物学效应，这些细胞从直接受照射的细胞接收了信号；然而，高能重离子诱导的旁观者反应尚未完全明确。在此，我们对汇合培养的受照射和旁观者成纤维细胞进行了微阵列分析。为了观察旁观者细胞中的效应，使用微束对1、5和25个位点分别用10个碳离子（18.3 MeV/u，103 keV/μm）进行靶向照射，其中粒子分别穿过0.00026%、0.0013%和0.0066%的细胞。对于受照射细胞，培养物分别暴露于相应宽束（108 keV/μm）的10%存活剂量（D）、0.1D和0.01D。无论靶点数量（1、5或25个位点）和时间（照射后2或6小时）如何，在旁观者细胞中均观察到相似的表达变化。在旁观者细胞中显示出超过1.5倍变化的874个探针中，25%上调，其余下调。这些基因包括与细胞通讯（PIK3C2A、GNA13、FN1、ANXA1和IL1RAP）、应激反应（RAD23B、ATF4和EIF2AK4）和细胞周期（MYCN、RBBP4和NEUROG1）相关的基因。通路分析揭示了G蛋白/PI-3激酶通路的连续旁观者激活。相反，与细胞周期或死亡（CDKN1A、GADD45A、NOTCH1和BCL2L1）以及细胞通讯（IL1B、TCF7和ID1）相关的基因在受照射细胞中上调，但在旁观者细胞中未上调。我们的结果表明受照射和旁观者细胞中的表达谱不同，并暗示受照射细胞与旁观者细胞之间的细胞间信号传导激活细胞内信号传导，导致旁观者细胞中的转录应激反应。
