Wang H P, Long X H, Sun Z Z, Rigaud O, Xu Q Z, Huang Y C, Sui J L, Bai B, Zhou P K
Department of Radiation Toxicology and Oncology, Beijing Institute of Radiation Medicine, Beijing, PR China.
Int J Radiat Biol. 2006 Mar;82(3):181-90. doi: 10.1080/09553000600632261.
To identify candidate genes specifically involved in response to low-dose irradiation in human lymphoblastoid cells; to better clarify the role of the human chromodomain helicase DNA binding protein 6 gene (CHD6), one of these genes, in cell proliferation and radiosensitivity.
DNA microarray technology was used to analyse global transcriptional profile in human lymphoblastoid AHH-1 cells at 4 h after exposure to 0.5 Gy of gamma-ray. Gene expression changes were confirmed by semi-quantitative reverse transcription--polymerase chain reaction (RT-PCR) and Northern blot. RNA interfering technology was employed to knock-down the CHD6 gene in A549 cells. Colony-forming ability was used to analyse radiosensitivity.
The microarray assay revealed a set of 0.5 Gy-responsive genes, including 30 up-regulated genes and 45 down-regulated genes. The up-regulated genes include a number of genes involved in: signal transduction pathways, e.g., STAT3, CAMKK2, SIRT1, CREM, MAPK3K7IP2 and GPR56; transcription or DNA-binding, e.g., CHD6, CRSP3, SNURF, SH2 domain binding protein 1 and MIZF. Some of the down-regulated genes are involved in: cytoskeleton and cell movement (WASF2, LCP1, MSN, NIPSNAP1, KIF2C); DNA replication and repair (MCM2, MCM3, MCM7 and XRCC-4). Radiation-increased expression of CHD6 was also found in A549 cells and HeLa cells. The sustained CHD6 induction was restricted to relatively low doses (0.2 Gy or 0.5 Gy), no change occurring after 4 Gy irradiation. Silencing of CHD6 mediated by siRNA increased the growth rate of A549 cells by 40 approximately 60%. Most importantly, silencing CHD6 led to an increased radioresistance of A459 cells to radiation doses up to 2 Gy, but barely affected the sensitivity of cells at 4 and 8 Gy.
This study has identified a set of genes responsive to 0.5 Gy of gamma-rays. CDH6 gene can be specifically up-regulated by low dose irradiation, and its inducible expression could be involved in a low dose hypersensitive response.
鉴定人类淋巴母细胞中对低剂量辐射有特异性反应的候选基因；更好地阐明这些基因之一的人类染色体结构域解旋酶DNA结合蛋白6基因（CHD6）在细胞增殖和放射敏感性中的作用。
利用DNA微阵列技术分析人类淋巴母细胞AHH-1细胞在接受0.5 Gy γ射线照射后4小时的整体转录谱。通过半定量逆转录-聚合酶链反应（RT-PCR）和Northern印迹法确认基因表达变化。采用RNA干扰技术敲低A549细胞中的CHD6基因。用集落形成能力分析放射敏感性。
微阵列分析揭示了一组对0.5 Gy有反应的基因，包括30个上调基因和45个下调基因。上调基因包括许多参与以下方面的基因：信号转导途径，如STAT3、CAMKK2、SIRT1、CREM、MAPK3K7IP2和GPR56；转录或DNA结合，如CHD6、CRSP3、SNURF、SH2结构域结合蛋白1和MIZF。一些下调基因参与：细胞骨架和细胞运动（WASF2、LCP1、MSN、NIPSNAP1、KIF2C）；DNA复制和修复（MCM2、MCM3、MCM7和XRCC-4）。在A549细胞和HeLa细胞中也发现CHD6的辐射诱导表达增加。CHD6的持续诱导仅限于相对低剂量（0.2 Gy或0.5 Gy），4 Gy照射后无变化。由siRNA介导的CHD6沉默使A549细胞的生长速率提高了约40%至60%。最重要的是，沉默CHD6导致A459细胞对高达2 Gy辐射剂量的放射抗性增加，但对4 Gy和8 Gy时细胞的敏感性几乎没有影响。
本研究鉴定了一组对0.5 Gy γ射线有反应的基因。CDH6基因可被低剂量辐射特异性上调，其诱导表达可能参与低剂量超敏反应。
