miRNAs介导辐射旁效应研究进展

辐射旁效应是指受辐射的细胞产生信号,并诱导未受辐照的细胞产生反应,即受辐射和未受辐射细胞之间的通讯以及这两种细胞内的信号转导效应。辐射对肿瘤细胞造成杀伤作用的同时,也会产生辐射旁效应给邻近的正常组织带来潜在危险。研究发现,电离辐射可直接改变miRNAs表达,并影响未受辐射的邻近组织中基因的表达,因此,miRNAs可能是受辐射细胞和未受辐射细胞之间信号通路调节的重要物质。本文就miRNAs在辐射旁效应中的作用进行综述。     

调节肿瘤放射敏感性的miRNAs研究进展

miRNA是一类非编码的小RNA, 它主要利用碱基互补配对的方式与特异性靶基因信使RNA的3'-非翻译区结合, 通过降解靶RNA或抑制蛋白质的翻译合成, 从而实现对靶基因转录后水平的调控。放射治疗是治疗肿瘤的主要手段之一, 肿瘤的辐射生物效应对其放疗效果至关重要, 也是确定某肿瘤组织辐射敏感或辐射耐受的一个重要因素。研究证实, miRNAs通过影响DNA损伤修复、细胞周期检查点、凋亡、信号转导、肿瘤组织微环境等因素参与肿瘤放疗敏感性的调控, miRNAs为肿瘤放射治疗提供了新途径。     

miRNAs在放射医学研究中的应用

microRNAs（miRNAs）是一类内源性的非编码RNA,通过与靶mRNA特异性的结合而导致靶mRNA降解或抑制其翻译,对基因进行转录后调控,进而影响各种生命活动。大量研究表明,miRNAs与辐射致癌效应、辐射增敏效应、肿瘤辐射抗拒和辐射旁效应密切相关,已成为放射医学研究的热点。笔者就miRNAs及其在放射医学研究中的应用作一综述。     

基于循环血miRNAs评估空间铁离子辐射暴露的新方法

目的寻找具有作为空间铁离子辐射生物标志物潜力的循环血microRNAs(miRNAs)分子,并探索基于这些分子的辐射暴露风险评估新方法。方法利用重离子加速器产生的高能铁离子束对小鼠进行全身照射,通过定制miRNA PCR array芯片检测了13种辐射相关的循环血miRNAs表达水平,筛选出4种miRNAs作为候选标志物进行验证。利用实时定量PCR技术检测了候选miRNAs在铁离子束照射下的剂量效应和时间效应关系。此外,利用多元线性回归的方法建立了结合4种辐射敏感miRNAs预测辐射暴露程度的数学模型,并通过受试者工作特征曲线对模型准确性进行了评估。结果铁离子束照射后,循环血中miR-21a、miR-200b表达水平上调,miR-574、miR-342表达水平下调,且具有较强的剂量效应关系,在6～72h内,其表达差异能稳定维持。结合4种候选miRNAs建立的多元线性回归方程在预测不同程度的辐射暴露方面具有很好的特异性和敏感性。结论循环血辐射敏感miRNAs具有作为空间铁离子辐射生物标志物的潜力,而基于这些循环血miRNAs的多元线性回归模型可应用于评估空间辐射暴露风险。     

空间辐射生物学效应及生物防护措施研究进展

目的 综述空间辐射的生物学效应及生物防护措施的研究进展,探讨各种生物防护途径的作用机制及未来的发展方向. 资料来源与选择国外该领域的研究及论著资料引用引用文献资料39篇. 资料综合空间辐射粒子尤其是高能重离子对人体细胞及组织器官有严重危害,某些药物及活性物可以通过抗自由基、调节免疫、调节细胞分裂周期等途径对抗辐射损伤效应. 结论 生物防护方法可以有效降低空间辐射带来的伤害,包括辐射诱导引起的癌症、免疫抑制以及神经损伤等不利效应.     

代谢重编程在电离辐射及其旁效应中的研究进展

代谢重编程是指肿瘤细胞为满足自身生长和能量的需求, 通过改变代谢模式来调节细胞生物学功能, 帮助自身抵御外界胁迫, 从而使细胞适应低氧、酸性、营养物质缺乏等微环境而快速增殖的现象。放射生物学研究发现, 电离辐射可通过诱导细胞代谢重编程产生辐射抗性;也可通过旁效应促进未受照射细胞发生代谢重编程, 从而赋予细胞癌变和辐射抗性能力。因此, 探索电离辐射和电离辐射旁效应中代谢重编程机制, 可以为辐射防护、放射治疗、放射损伤诊断等提供新的思路和理论依据。本文对代谢重编程在电离辐射及其旁效应中的研究进展进行综述。     

高剂量率近距离放射治疗剂量学研究进展

近年来高剂量率近距放射治疗技术(high dose rate brachytherapy, HDR-BT)及设备均有较大发展,剂量分布及治疗计划系统的改善提高了HDR-BT治疗的准确性,从而推动其成为多种肿瘤的放射治疗的重要组成部分.本文介绍了HDR-BT所用的放射源、剂量分布、施源器、剂量优化、辐射生物效应等,探讨了HDR-BT剂量学未来的研究方向.     

p53调控的能量代谢对辐射效应的影响

p53基因一直是肿瘤病因学、放射生物学的研究热点,但受其调控的能量代谢在辐射生物效应中的作用还存在许多未知因素.了解p53基因调控的能量代谢对探讨肿瘤放射治疗疗效、辐射损伤、辐射致癌的早期筛选生物指标和分子流行病学调查均有着极其重要的意义.该文概述了此方面的研究进展.     

辐射旁效应的发生机制及其研究进展

深入了解放射生物学理论对于辐射影响的研究至关重要。辐射旁效应(RIBE)自被发现以来就成为了放射生物学领域的研究热点, 辐射对靶向和非靶向细胞、组织、器官的直接和间接作用影响着放射治疗恶性肿瘤的进程和结局。截至目前, 大量体内外实验研究揭示了RIBE的发生机制, 辐照产生的外源性介质迁移到旁组织或细胞中, 刺激各种信号通路的激活, 导致了免疫及炎症反应、表观遗传调节和辐射的致癌转化。笔者就RIBE及其发生机制的研究现状进行综述, 以期为辐射防护新药的开发及放疗疗效的提高提供一定的理论基础。     

早期生长反应基因1启动子介导肿瘤基因-放疗的研究进展

早期生长反应基因1(Egr-1)启动子为Egr-1上游的顺式作用元件,其活性受电离辐射、自由基等诱导剂的调控.Egr-1与治疗基因结合(如肿瘤坏死因子α基因、自杀基因等)构成基因-放射治疗体系,利用辐射在肿瘤局部从时间、空间调控治疗基因的表达,使表达产物局限于肿瘤局部发挥肿瘤杀伤效应,并降低了不良反应.放射治疗与基因治疗的结合为肿瘤治疗提供了新方法.     

电离辐射诱导microRNA研究进展

微小RNA（microRNA,miRNA）是一类长度为21~23 nt的单链非编码小RNA。在真核生物中miRNA主要通过与编码蛋白质基因的信使RNA（mRNA）配对结合,在转录后水平抑制基因表达。越来越多的证据表明,miRNA与氧化应激特别是辐射生物效应相关,miRNA有可能成为放射病治疗的潜在新靶点。本文概述电离辐射诱导miRNA的研究进展。     

60Co γ线照射血管内皮细胞外泌体中miRNA的鉴定分析

目的 利用微小RNA(miRNA)芯片和生物信息学技术,研究受照射人脐静脉血管内皮细胞(HUVEC)产生的外泌体miRNA组分的变化,为揭示血管组织放射损伤及其旁效应机制提供新的线索.方法 超高速离心法收集对照组和4 Gy剂量照射组的HUVEC外泌体,运用电镜及Western印迹技术对外泌体进行鉴定,miRNA芯片技术分析细胞内和外泌体中miRNA表达谱,qRT-PCR法验证部分差异miRNA,通过miRDB和TargetScan预测差异miRNA的靶基因,DAVID、KEGG等在线工具进行生物信息学分析.结果 HUVEC经4 Gy照射后外泌体miRNA与对照组相比,照后0.5 h共鉴定到18个发生表达变化的miRNA分子,5个表达上调,13个表达下调;照后2 h鉴定出16个表达上调、5个表达下调miRNA分子;细胞内miRNA与对照组相比,照射后0.5、2 h分别有38个和85个差异表达miRNA,且差异有统计学意义(P<0.01).生物信息学结果表明,这些表达变化的miRNA可能通过参与调控MAPK、Ras、PI3K-Akt信号通路等途径影响细胞辐射旁效应.结论 电离辐射损伤导致血管内皮细胞外泌体miRNA分子组分和表达水平发生显著改变,这些miRNA的靶基因组产物在细胞放射损伤反应的信号通路调节中发挥重要作用.     

X射线诱导非小细胞肺癌A549细胞凋亡的适应性反应及相关miRNA筛选的研究

目的:研究X射线辐射诱导非小细胞肺癌（NSCLC) A549细胞凋亡的适应性反应,并筛选适应性反应相关的微RNA (miRNA）。方法:将NSCLC A549细胞分为6组,包括50 mGy+20 Gy、200 mGy+20 Gy、20 Gy、50 mGy、200 mGy照射组及对照组（0 Gy）,前2组细胞分别用50、...     

60Co γ射线照射致小鼠肝脏的miRNAs表达改变

目的 应用miRNA芯片筛选4 Gy60Co γ射线照射后小鼠肝脏中差异表达的miRNAs,生物信息学方法探索差异表达miRNAs调控的主要功能.方法 SPF级C57BL/6J小鼠接受4 Gy60Co γ射线单次全身照射后,进行外周血白细胞计数和骨髓嗜多染红细胞微核计数.应用miRNA芯片筛选照射后小鼠肝脏中差异表达的miRNAs,用miRNA特异引物对部分差异表达miRNA进行实时定量PCR(real time PCR)验证.运用生物信息学方法,对差异miRNAs靶基因及调控功能进行预测.结果 4 Gyγ射线照射后,外周血白细胞总数与对照组相比显著减少(t=2.87,P＜0.05),而骨髓嗜多染红细胞微核率与对照组相比显著增加(t=-2.91,P＜0.05).miRNA芯片结果显示,照射组与对照组差异表达的miRNAs共17个,其中9个表达上调,8个表达下调.miR-124和miR-34a的实时荧光定量RT-PCR验证结果与芯片结果一致.GO分析发现,与黏附、细胞周期相关的通路被抑制,一些免疫相关通路被激活.结论 miR-34a和miR-194参与了急性辐射损伤的调控,起主要调控作用的miRNAs还有miR-124、miR-382和miR-92a*.

Abstract：

Objective To investigate the differential expression profiles of microRNAs in the liver of 60Co γ-ray irradiated mice using microRNA microarray and to explore their main functions by bioinformatic analysis.Methods After SPF C57BL/6J mice expose to 4 Gy-single whole body radiation,total number of peripheral WBC and the fMNPCE were measured at 3 d.The differentially expressed miRNAs in mouse liver were detected with miRNA microarray,miRNA-124 and miR-34a were confirmed by real time RT-PCR assay.Bioinformatic analysis was applied to explore target genes and the main functions of the differential expressed miRNAs.Results Compared with control group,the total number of peripheral WBC decreased( t = 2.87,P ＜ 0.05 ) ,while the fMNPCE in bone marrow increased ( t =-2.91,P ＜0.05) after 4 Gy γ-ray irradiation.miRNA microarray revealed that 17 miRNAs were differentially expressed,in which 9 up-regulated,8 down-regulated.The expression levels of miR-124 and miR-34a were coincident with the result of real time RT-PCR.GO analysis showed that some pathways including adherens junction and cell cycle were suppressed,while some immune-related pathways were activated.Conclusions miR-34a and miR-194 were involved in the regulation of acute radiation damage,some other miRNAs including miR-124、miR-382 and miR-92a* also played important roles in radiation process.     

内含子miRNA反馈调节宿主基因的表达与功能研究进展

miRNA是近年来发现的一类重要的基因表达调控因子。研究发现,许多miRNA位于编码蛋白基因（宿主基因）的内含子中,称为内含子miRNA。现有的证据表明,大多数内含子miRNA和它们的宿主基因表达一致,提示这些内含子miRNA参与宿主基因在功能和表达上的调控,本文就这方面的最新研究进展做一综述。     

miRNA参与p53基因调控网络研究进展

在细胞增殖和细胞死亡等过程中均发现一些miRNA可以作为肿瘤抑制基因或癌基因参与调节。研究发现miR-34作为p53转录激活的靶分子,参与了包括细胞周期阻滞和细胞凋亡等过程的调节,miR-34的缺失可使p53介导的细胞效应受阻。miR-29可激活p53的表达并诱导p53介导的细胞凋亡。此外,还有许多miRNA分子受到p53的转录抑制。一种miRNA可调节多种不同的靶蛋白分子,因此大大拓展了p53调控网络的层面。越来越多的证据表明miRNA参与了癌基因和抑癌基因网络的调控,同时为肿瘤治疗提供了新的治疗策略。     

Inactivation of chosen dehydrogenases by the products of water radiolysis and secondary albumin and haemoglobin radicals

Purpose : To review studies of radiation responses in the haemopoietic system in the context of radiation-induced genomic instability, bystander effects and inflammatory-type processes. Results : There is considerable evidence that cells that themselves are not exposed to ionizing radiation but are the progeny of cells irradiated many cell divisions previously may express a high frequency of gene mutations, chromosomal aberrations and cell death. These effects are collectively known as radiation-induced genomic instability. A second untargeted effect results in non-irradiated cells exhibiting responses typically associated with direct radiation exposure but occurs as a consequence of contact with irradiated cells or by receiving soluble signals from irradiated cells. These effects are collectively known as radiation-induced bystander effects. Reported effects include increases or decreases in damage-inducible and stress-related proteins; increases or decreases in reactive oxygen species, cell death or cell proliferation, and induction of mutations and chromosome aberrations. This array of responses is reminiscent of effects mediated by cytokines and other similar regulatory factors that may involve, but do not necessarily require, gap junction-mediated transfer, have multiple inducers and a variety of context-dependent consequences in different cell systems. That chromosomal instability in haemopoietic cells can be induced by an indirect bystander-type mechanism both in vitro and in vivo provides a potential link between these two untargeted effects and there are radiation responses in vivo consistent with the microenvironment contributing secondary cell damage as a consequence of an inflammatory-type response to radiation-induced injury. Intercellular signalling, production of cytokines and free radicals are features of inflammatory responses that have the potential for both bystander-mediated and persisting damage as well as for conferring a predisposition to malignancy. The induction of bystander effects and instabilities may reflect interrelated aspects of a non-specific inflammatory-type response to radiation-induced stress and injury and be involved in a variety of the pathological consequences of radiation exposures.     

Radiation-induced genomic instability and bystander effects: related inflammatory-type responses to radiation-induced stress and injury? A review

PURPOSE: To review studies of radiation responses in the haemopoietic system in the context of radiation-induced genomic instability, bystander effects and inflammatory-type processes. RESULTS: There is considerable evidence that cells that themselves are not exposed to ionizing radiation but are the progeny of cells irradiated many cell divisions previously may express a high frequency of gene mutations, chromosomal aberrations and cell death. These effects are collectively known as radiation-induced genomic instability. A second untargeted effect results in non-irradiated cells exhibiting responses typically associated with direct radiation exposure but occurs as a consequence of contact with irradiated cells or by receiving soluble signals from irradiated cells. These effects are collectively known as radiation-induced bystander effects. Reported effects include increases or decreases in damage-inducible and stress-related proteins; increases or decreases in reactive oxygen species, cell death or cell proliferation, and induction of mutations and chromosome aberrations. This array of responses is reminiscent of effects mediated by cytokines and other similar regulatory factors that may involve, but do not necessarily require, gap junction-mediated transfer, have multiple inducers and a variety of context-dependent consequences in different cell systems. That chromosomal instability in haemopoietic cells can be induced by an indirect bystander-type mechanism both in vitro and in vivo provides a potential link between these two untargeted effects and there are radiation responses in vivo consistent with the microenvironment contributing secondary cell damage as a consequence of an inflammatory-type response to radiation-induced injury. Intercellular signalling, production of cytokines and free radicals are features of inflammatory responses that have the potential for both bystander-mediated and persisting damage as well as for conferring a predisposition to malignancy. The induction of bystander effects and instabilities may reflect interrelated aspects of a non-specific inflammatory-type response to radiation-induced stress and injury and be involved in a variety of the pathological consequences of radiation exposures.     

Combining brachytherapy and immunotherapy to achieve in situ tumor vaccination: A review of cooperative mechanisms and clinical opportunities

As immunotherapies continue to emerge as a standard component of treatment for a variety of cancers, the imperative for testing these in combination with other standard cancer therapies grows. Radiation therapy may be a particularly well-suited partner for many immunotherapies. By modulating immune tolerance and functional immunogenicity at a targeted tumor site, radiation therapy may serve as a method of in situ tumor vaccination. In situ tumor vaccination is a therapeutic strategy that seeks to convert a patient's own tumor into a nidus for enhanced presentation of tumor-specific antigens in a way that will stimulate and diversify an antitumor T cell response. The mechanisms whereby radiation may impact immunotherapy are diverse and include its capacity to simultaneously elicit local inflammation, temporary local depletion of suppressive lymphocyte lineages, enhanced tumor cell susceptibility to immune response, and immunogenic tumor cell death. Emerging data suggest that each of these mechanisms may display a distinct dose–response profile, making it challenging to maximize each of these effects using external beam radiation. Conversely, the highly heterogenous and conformal dose distribution achieved with brachytherapy may be optimal for enhancing the immunogenic capacity of radiation at a tumor site while minimizing off-target antagonistic effects on peripheral immune cells. Here, we review the immunogenic effects of radiation, summarize the clinical rationale and data supporting the use of radiation together with immunotherapies, and discuss the rationale and urgent need for further preclinical and clinical investigation specifically of brachytherapy in combination with immunotherapies. Harnessing these immunomodulatory effects of brachytherapy may offer solutions to overcome obstacles to the efficacy of immunotherapies in immunologically “cold” tumors while potentiating greater response in the context of immunologically “hot” tumors.