Egr-1基因与肿瘤及放射治疗研究进展

目的:总结关于早期生长反应-1(Egr-1)基因在肿瘤和放射治疗中的研究进展.方法:应用PubMed及CNKI期刊全文数据库检索系统,以“Egr-1基因、肿瘤、放射治疗、细胞凋亡”为关键词,检索1993-01-2012-03的相关文献,共检索到英文文献691篇,中文文献129篇.纳入标准:1)Egr-1基因的结构;2)Egr-1基因在肿瘤中的表达;3)Egr-1基因对肿瘤的作用;4)Egr-1基因与放射治疗.根据纳入标准符合分析文献41篇.结果:Egr-1基因的表达存在于绝大多数的肿瘤中,对肿瘤的发生和发展具有抑制或促进作用;肿瘤细胞放射后可诱导Egr-1基因表达,并可引起下游基因表达及细胞凋亡;放射后的Egr-1基因表达水平与肿瘤细胞凋亡有关.结论:Egr-1基因在肿瘤中具有重要作用,对其不断深入研究可为肿瘤的治疗尤其是放疗提供更多新的依据.     

中国人群中Egr-1基因多态性与胶质瘤的相关性研究

目的 分析我国人群中Egr-1基因在胶质瘤患者中多态性的表达.方法 选取231例胶质瘤患者为病例组,121例非肿瘤患者为对照组,应用Taqman技术检测两组患者Egr-1基因多态性,应用SPSS 15.0统计软件对Taqman技术成功检测分型结果进行统计学处理,分析该位点多态性.结果 统计学分析结果显示:病例组中T/T+C/C基因型频率、T等位基因频率分别为29.9%、47.6%,均小于对照组的37.2%、52.1%,但差异均无统计学意义(P>0.05).结论 Egr-1基因多态性与胶质瘤的发病风险之间无明显关联.     

Snm1B/Apollo mediates replication fork collapse and S Phase checkpoint activation in response to DNA interstrand cross-links

The removal of DNA interstrand cross-links (ICLs) has proven to be notoriously complicated due to the involvement of multiple pathways of DNA repair, which include the Fanconi anemia/BRCA pathway, homologous recombination and components of the nucleotide excision and mismatch repair pathways. Members of the SNM1 gene family have also been shown to have a role in mediating cellular resistance to ICLs, although their precise function has remained elusive. Here, we show that knockdown of Snm1B/Apollo in human cells results in hypersensitivity to mitomycin C (MMC), but not to IR. We also show that Snm1B-deficient cells exhibit a defective S phase checkpoint in response to MMC, but not to IR, and this finding may account for the specific sensitivity to the cross-linking drug. Interestingly, although previous studies have largely implicated ATR as the major kinase activated in response to ICLs, we show that it is activation of the ATM-mediated checkpoint that is defective in Snm1B-deficient cells. The requirement for Snm1B in ATM checkpoint activation specifically after ICL damage is correlated with its role in promoting double-strand break formation, and thus replication fork collapse. Consistent with this result Snm1B was found to interact directly with Mus81-Eme1, an endonuclease previously implicated in fork collapse. In addition, we also show that Snm1B interacts with the Mre11-Rad50-Nbs1 (MRN) complex and with FancD2 further substantiating its role as a checkpoint/DNA repair protein.     

Egr-1启动的融合肿瘤治疗基因研究进展

目前,一种新的提高恶性肿瘤基因治疗特异性的方法是应用放射线诱导的早期生长反应基因-1（Egr-1）启动子来启动治疗基因的表达。现就近几年来放射诱导Egr-1启动子启动下游目的基因的表达在恶性肿瘤治疗方面的研究进展作一综述。     

Transforming growth factor-beta1 mediates cellular response to DNA damage in situ

Transforming growth factor (TGF)-beta1 is rapidly activated after ionizing radiation, but its specific role in cellular responses to DNA damage is not known. Here we use Tgfbeta1 knockout mice to show that radiation-induced apoptotic response is TGF-beta1 dependent in the mammary epithelium, and that both apoptosis and inhibition of proliferation in response to DNA damage decrease as a function of TGF-beta1 gene dose in embryonic epithelial tissues. Because apoptosis in these tissues has been shown previously to be p53 dependent, we then examined p53 protein activation. TGF-beta1 depletion, by either gene knockout or by using TGF-beta neutralizing antibodies, resulted in decreased p53 Ser-18 phosphorylation in irradiated mammary gland. These data indicate that TGF-beta1 is essential for rapid p53-mediated cellular responses that mediate cell fate decisions in situ.     

小鼠Egr-1基因启动子的克隆及其辐射诱导基因表达

目的：研究克隆小鼠Ｅｇｒ－１基因启动子及其辐射诱导基因表达特征。方法：用合成的一对引物,以ＢＡＬＢ／ｃ小鼠基因组为模板,扩增出４４９ｂｐ大小含６个ＣＣ（Ａ／Ｔ）６ＧＧ基序的序列,通过亚克隆技术分别将其插入ｐＢｌｕｅｓｃｒｉｐｔⅡ测序载体和ｐＨＧＦＰ－Ｓ６５Ｔ报告载体中,利用测序载体对克隆的ＤＮＡ序列进行分析。报告质粒载体经Ｌｉ－ｐｏｆｅｃＴＡＭＩＮＥ脂质体介导转染ＣＯＳ－７细胞后给予γ射线照射或Ｈ