大鼠脑胶质瘤伽玛刀治疗对细胞凋亡和Caspase-3、Fas表达的影响

目的　研究大鼠脑胶质瘤伽玛刀治疗后肿瘤细胞凋亡的时程变化和Caspase 3、Fas的表达。方法　立体定向法制作C6大鼠脑胶质瘤模型 6 0只 ,分为治疗组和对照组 ,治疗组于肿瘤接种后 14d行伽玛刀治疗 ,治疗后不同时间点行流式细胞学检查测定肿瘤细胞的凋亡率以及Caspase 3和Fas基因蛋白表达情况 ,分析凋亡率与两种蛋白的相关性。结果　与对照组相比 ,治疗组肿瘤细胞的凋亡率明显增高 (P <0 0 5 ) ,治疗后 4 8h肿瘤细胞凋亡率达高峰 ,然后逐渐下降 ;Caspase 3和Fas的表达情况与凋亡率的变化呈正相关 (r1 =0 92 8,r2 =0 916 )。结论　肿瘤细胞的凋亡为伽玛刀治疗胶质瘤疗效之一 ,Caspase 3和Fas基因可能参与和调节伽玛刀照射后肿瘤细胞凋亡。     

重离子辐射对人外周血T淋巴细胞生物学性能的影响

目的研究重离子对人外周血T淋巴细胞增殖、凋亡等生物学性能的影响并探讨其机制,为肿瘤放射治疗的辐射防护提供实验依据和基础。方法 Ficoll分离法分离人外周血T淋巴细胞,采用12C重离子束坪区照射,照射样品能量为70 MeV、LET=29 keV/μm,照射剂量为1.0和2.0 Gy,剂量率为0.5 Gy/min。分别于照射后12、24h,RT-PCR检测凋亡相关基因Bcl-2,Bax,Caspase3,Caspase8和Caspase9的表达;于照射后24、48 h,CCK8法检测细胞增殖能力;于照射后24、48 h,采用AnnexinV-PE/7-AAD、AnnexinV-FITC/PI法检测凋亡发生,并采用RT-PCR检测凋亡相关蛋白Bcl-2、Bax和Caspase3的表达。结果重离子照射可明显抑制人外周血T淋巴细胞的增殖,随着剂量增大,抑制作用更加明显。同时,重离子照射可促进T淋巴细胞的凋亡,特别是对于晚期凋亡的诱导作用（P〈0.01）。RT-PCR检测结果显示,重离子辐射可抑制抗凋亡蛋白Bcl-2的表达,促进促凋亡蛋白Bax和Caspase3的表达（P〈0.01）。结论重离子辐射可显著影响抑制T淋巴细胞的增殖并促进其凋亡。     

细胞凋亡信号通路调控与肿瘤辐射敏感性

电离辐射作用于细胞引起各种损伤而导致细胞死亡的主要机制是诱导细胞发生凋亡。高剂量（大于10Gy）的电离辐射会使细胞发生被动的坏死过程，而促发细胞凋亡所需要的辐射剂量远远低于促发细胞坏死所需剂量。在肿瘤放射治疗过程中，降低辐射剂量诱导肿瘤细胞发生凋亡，而使正常细胞受照剂量降低，减小损伤，具有重要的生物学意义。因此临床上利用放疗方法诱导肿瘤细胞凋亡成为众多肿瘤治疗的目标之一。但由于肿瘤细胞可对放射治疗产生耐受，导致疗效下降，提高肿瘤细胞对放疗的敏感性一直是科研人员关注的研究方向。     

细胞凋亡抑制和肿瘤细胞对放射治疗的耐受

临床上利用放疗方法诱导肿瘤细胞凋亡为众多治疗肿瘤的目标之一，但是由于肿瘤细胞可对放射治疗产生耐受而导致疗效下降。本文从基因调控异常、信号转导障碍等方面探讨细胞凋亡抑制与肿瘤耐受放疗的机制。     

Smac联合照射对肿瘤细胞的抑制效应

恶性肿瘤(malignant tumor)是当前人类健康面临的主要威胁之一,而寻找其有效的治疗方案仍是国内外研究的热点.放射治疗是临床上应用最广泛和最重要的治疗手段之一,但肿瘤临近部位正常组织的放射损伤和某些肿瘤对辐射具有抗性等问题,至今影响其放疗的疗效和应用.根据放射治疗和基因治疗各自的特点,Weichselbaum等[1]提出将两者联合应用,即肿瘤基因放射治疗的设想,其含义是将辐射诱导性基因的调控序列与肿瘤杀伤基因相耦联,转染肿瘤细胞,在对肿瘤实施局部放疗的同时,诱导肿瘤杀伤基因表达的增强,产生辐射和基因表达产物的协同抑瘤作用.该疗法一方面将放疗与基因治疗有机地结合,发挥协同作用;另一方面,由于辐射具有靶向性和可控性,实现了对杀伤基因表达的时空调控[2].因此,肿瘤基因放射治疗近年来已成为肿瘤治疗领域新的研究方向.本文仅对Smac及其生物学特性、在肿瘤治疗中应用、联合放疗对肿瘤细胞的抑制效应及对联合放疗的几点体会等方面内容作一简要的综述.     

低剂量辐射对肿瘤细胞凋亡、细胞周期以及凋亡相关蛋白bcl-2的影响

目的　探讨低剂量辐射对小鼠移植肿瘤细胞的凋亡、细胞周期以及相关蛋白bcl 2表达的影响。方法　昆明种雄性小鼠左后肢腹股沟皮下接种S1 80肉瘤细胞 ,接种后 7dγ射线全身照射 75mGy,照射后 2 4 ,48h分别处死 ,直接测量肿瘤大小变化 ,并取肿瘤组织分别进行流式细胞仪分析凋亡、细胞周期 ,以免疫组化染色半定量分析凋亡相关蛋白bcl 2表达的变化。结果　与直接荷瘤组相比 ,低剂量照射组肿瘤生长缓慢 (P <0 0 5) ,2 4h后肿瘤细胞阻滞于G1 期 ,bcl 2蛋白表达下降 ,48h后肿瘤细胞凋亡增加 (P <0 0 0 1 )。结论　低剂量辐射可使机体肿瘤细胞阻滞于G1 期 ,并通过凋亡相关蛋白表达变化导致肿瘤细胞凋亡增加 ,明显提高机体抗肿瘤的作用 ,具有肿瘤治疗和辅助放化疗的实际临床意义     

新型Smac模拟物Tat-Smac N7的肿瘤细胞辐射增敏作用

目的 观察Tat-Smac N7融合肽对人肺癌细胞系H460和人食管癌细胞系EC109的辐射增敏作用,探讨其辐射增敏机制.方法 取对数生长期H460和EC109细胞,分为DAPI对照组、FITC-Smac N7和FITC-Tat-Smac N7组,荧光显微镜观察两种细胞不同时间药物入核情况.取对数生长期H460和EC109细胞,分为单纯照射组、照射联合Tat-Smac N7组,单纯照射组给予0、2、4、6 Gy照射,照射联合Tat-Smac N7组中Tat-Smac N7的浓度为20 μmol/L,WST-1测定Tat-Smac N7的辐射增敏作用.取对数生长期H460和EC109细胞,分为对照组、Tat-Smac N7组、单纯照射组和照射联合Tat-Smac N7组,吸收剂量为4 Gy,Tat-Smac N7浓度为20 μmol/L,细胞流式分析仪测定细胞不同时间的细胞凋亡率.结果 Tat-Smac N7融合蛋白进入2种细胞系后2h可以有蓄积,且这种蓄积可延续到24 h,而Smac N7则不能进入细胞.Tat-Smac N7能够增强H460和EC109细胞的辐射敏感性(F=22.2、13.2,P＜0.05),照射联合Tat-Smac N7可明显增加辐射诱导的细胞凋亡率(24 h:F=9.32、5.86,P＜0.05;48 h:F =7.09、8.25,P＜0.05).Tat-Smac N7联合照射后凋亡诱导效应具有时间依赖性.结论 Tat-Smac N7融合肽可促进肿瘤细胞的辐射敏感性,作为一种新的Smac蛋白类似物,有望用于肿瘤的辐射增敏治疗.     

细胞凋亡抑制和肿瘤细胞对放射治疗的耐受

临床上利用放疗方法诱导肿瘤细胞凋亡为众多肿瘤的目标之一，但是由于肿瘤细胞可对放射治疗产生耐受导致疗效下降。本文从基因调控异常、信号转导障碍等方面探讨细胞凋亡抑制与肿瘤耐受放疗的机制。     

细胞凋亡的线粒体调控机制与电离辐射

线粒体在外界刺激(如电离辐射)诱发细胞凋亡中起中心调控作用。各种死亡信号通过Bcl-2家族蛋白或直接诱导线粒体膜通透性增加、细胞色素c释放和caspases激活，最终引起细胞凋亡。线粒体膜通透性改变的机制，目前还不完全清楚。简要综述细胞凋亡的线粒体调控机制及电离辐射在其机制中的可能作用。     

基因治疗联合放射治疗恶性肿瘤

肿瘤治疗是目前医学研究的重点之一,基因治疗与放射治疗方法的结合倍受重视,根据技术特点这种联合治疗方法主要有:免疫基因治疗联合放疗、直接杀伤或抑制肿瘤细胞的基因治疗联合放疗、抗肿瘤血管生成的基因治疗联合放疗以及辐射保护性基因治疗.综述了近年来基因治疗联合放射治疗恶性肿瘤的研究现状以及可能的作用机制.     

Smac基因过表达对宫颈癌HeLa细胞放疗敏感性的影响

目的探讨转染Smac基因过表达对宫颈癌细胞放疗敏感性的影响,寻求改善宫颈癌放疗疗效的新途径。方法将Smac基因转染入宫颈癌HeLa细胞株,G418筛选获得亚克隆细胞,RTPCR、Westernblot法检测癌细胞Smac基因表达。X射线照射后,采用MTT比色法检测癌细胞体外生长活性;透射电镜、AnnexinV-FITC和碘化丙啶双染色流式细胞仪法检测癌细胞凋亡及比率;Westernblot、比色法检测细胞内Caspase-3蛋白表达和活性水平。结果RTPCR和Westernblot证实所获宫颈癌亚克隆细胞HeLaSmac的SmacmRNA、蛋白表达水平均显著高于HeLa(P<0.01)。8GyX射线照射后,HeLaSmac细胞生长活性较HeLa细胞减弱10.19%(P<0.01),透射电镜下可见部分HeLaSmac细胞发生典型凋亡形态学改变,凋亡率为16.4%,显著高于对照组HeLa细胞(凋亡率为6.2%,P<0.01)。与HeLa细胞比较,HeLaSmac细胞内Caspase3表达显著增加(P<0.01),活性水平提高3.42倍(P<0.01)。结论稳定转染外源性Smac基因使其在宫颈癌细胞株中过表达,能提高癌细胞中Caspase3的表达和活性,增强放疗对癌细胞的诱导凋亡作用,有望成为改善宫颈癌放疗效果的新途径。     

肿瘤相关巨噬细胞在放疗中的研究进展

肿瘤相关巨噬细胞（TAMs）与肿瘤的发生、发展、转移和复发密切相关。TAMs可根据表型及功能的不同分为M1型和M2型,分别与抗肿瘤免疫和促进肿瘤进展有关。放疗是大多数实体瘤的主要治疗方式之一,其可以直接杀伤肿瘤细胞,也可以间接调控肿瘤免疫微环境（包括TAMs）,导致TAMs向放疗抵抗型或放疗敏感型发展,从而影响放疗的疗效。靶向TAMs来抑制其促肿瘤作用以及促进TAMs向M1型复极化已经成为极有希望的肿瘤治疗方式。靶向TAMs与放疗联合治疗能够协同抑制肿瘤进展、增强疗效并减少放疗抵抗。笔者就TAMs在肿瘤放疗中的角色和相互作用机制以及靶向TAMs与放疗联合治疗的最新进展进行综述。     

脑胶质瘤治疗新策略——STAT3 RNA干扰结合传统放疗

STAT3基因是近年来发现的凋亡抑制基因,具有抑制凋亡和参与细胞周期调控的双重功能.研究报道证明,在基础和临床实验中STAT3基因与放、化疗的敏感性有着密切的关系.因而目前研究关注于以STAT3 基因为靶点的基因治疗,尤其是RNA干扰技术抑制STAT3 基因的表达,增加肿瘤的自发性凋亡和放、化疗诱导的凋亡,抑制肿瘤生长,提高肿瘤对放、化疗的敏感性.     

Zelltodliganden in Kombination mit ionisierender Strahlung: Rationale und Kenntnisstand

BACKGROUND: Apart from optimization of the radiation technology, future new strategies in radiation oncology will focus on the biological optimisation leading to improved adaptation of the tumor therapy on each tumor entity. In this regard, different areas of biological research may be distinguished: prediction, development of new cytotoxic agents, improvement of the tolerance of normal tissue and the optimisation of radiochemotherapy. MATERIAL AND METHOD: For the development of new strategies the knowledge of molecular mechanisms of radiation induced cell death is essential. In the present article a novel biological strategy for optimisation of radiotherapy is introduced. RESULTS: Distinct pathways mediate apoptosis in response to death receptor stimulation and ionizing radiation although an overlapping set of molecules is involved. TRAIL (TNF alpha-related apoptosis inducing ligand) is a type-II membrane protein belonging to the TNF family, which preferentially induces apoptotic cell death in a wide variety of tumor cells but not in normal cells. Based on the assumption of distinct signalling pathways, combination of TRAIL and ionizing radiation seems ideal to increase the therapeutic efficacy. Our study presents the rationale, own data, data of other groups as well as the current status of the latest findings regarding the function and physiological role of the TRAIL death ligand. CONCLUSIONS: Apoptosis resistance towards ionising radiation is not associated with a general apoptosis resistance. Death ligands, for example TRAIL trigger apoptosis even in cells not undergoing apoptosis in response to radiation. A combination of both modalities induces additive or synergistic effects in regard to apoptosis induction and eradication of clonogenic tumor cells. Thus, the combination of TRAIL with radiation proofs that novel treatment strategies may be developed on the basis of molecular or cell biological research.     

靶向DNA损伤应答关键分子在肿瘤放疗增敏中的应用

放射治疗是临床肿瘤治疗的重要手段,主要通过破坏DNA双链对肿瘤细胞造成严重损伤。然而,其作为单一的治疗手段,治疗效果受肿瘤细胞固有DNA损伤修复能力的影响。多项研究表明,靶向调节DNA损伤响应关键分子可以有效抑制DNA损伤修复,协同增强放化疗敏感性。本文对一些关键的DNA损伤响应抑制剂联合放疗、化疗在多种肿瘤治疗中的应用进行了总结,并阐述了联合治疗诱导由环鸟嘌呤核苷酸腺嘌呤核苷酸合成酶-干扰素基因刺激因子介导的免疫反应。最后总结和展望了联合治疗存在的挑战和发展前景。     

Clinical applications of positron emission tomography/computed tomography treatment planning

Positron emission tomography/computed tomography (PET/CT) has provided an incremental dimension to the management of cancer patients by allowing the incorporation of important molecular images in radiotherapy treatment planning, ie, direct evaluation of tumor metabolism, cell proliferation, apoptosis, hypoxia, and angiogenesis. The CT component allows 4D imaging techniques, allowing improvements in the accuracy of treatment delivery by compensating for tumor/normal organ motion, improving PET quantification, and correcting PET and CT image misregistration. The combination of PET and CT in a single imaging system to obtain a fused anatomical and functional image data is now emerging as a promising tool in radiotherapy departments for improved delineation of tumor volumes and optimization of treatment plans. PET has the potential to improve radiotherapy planning by minimizing unnecessary irradiation of normal tissues and by reducing the risk of geographic miss. PET influences treatment planning in a high proportion of cases and therefore radiotherapy dose escalation without PET may be futile. This article examines the increasing role of hybrid PET/CT imaging techniques in process of improving treatment planning in oncology with emphasis on non small cell lung cancer.     

Increased cytotoxicity by the combination of radiation and diospyrin diethylether in fibrosarcoma in culture and in tumor

OBJECTIVE: Radio-resistance in tumor cells and associated escape from apoptotic mechanism is a major problem in clinical cancer radiotherapy. Therefore, as a strategy to enhance the apoptosis, a combination of radiation and tumor-selective cytotoxic agents might improve the efficacy of treatment. Thus, the radiomodifying potential of diospyrin diethylether (D7), a plant-derived antitumor agent, was studied in fibrosarcoma tumor, both in vitro and in vivo. MATERIAL AND METHODS: Mouse and human fibrosarcoma (Wehi164; HT1080) cells were treated with D7, alone, or in combination with radiation, for determination of cytotoxicity, clonogenic survival, and apoptotic death assays. Involvement of oxidative mechanism and nuclear factor kappa B (NF-kappaB) was studied in different treatment groups. In addition, fibrosarcoma-bearing mice were treated with D7 (intravenously, two doses, each of 1 mg/kg body weight) combined with radiation (two fractions of 2.5 Gy each) at appropriate intervals. The tumor volume was measured to assess 'tumor growth delay', and liver function enzymes in the serum of mice were estimated after the treatments. RESULTS: A combination treatment with D7 and radiation showed enhancement in cytotoxicity and apoptotic induction and decrease in clonogenic survival of tumor cells, as compared to the treatments with the drug or radiation alone. Moreover, D7 in combination with radiation could significantly inhibit the radiation-induced NF-kappaB activation, and showed the generation of comparatively more intracellular reactive oxygen species (ROS). Similarly, a combination of D7 and radiation in vivo caused significant inhibition of tumor growth in vivo, and restoring the liver enzyme activity to the 'normal' level. CONCLUSION: The combined treatment with quinonoid D7 and radiation caused increased cytotoxicity compared to single treatment with either agent alone in fibrosarcoma tumor systems, both in vitro and in vivo.     

大鼠脑损伤后XIAP与Smac／DIABLO表达的实验研究

目的：观察大鼠颅脑损伤后脑组织中XIAP与Smac／DIABLO表达变化及神经细胞凋亡,探讨颅脑损伤后神经细胞凋亡机制。方法：36只健康雄性Wistar大鼠,随机分为假手术组（sham组）及脑损伤组（TBI组）,采用自由落体法建立大鼠脑损伤模型,用免疫组织化学方法检测XIAP、Smac／DIABLO的表达,TUNEL法检测细胞凋亡。结果：与sham组相比,TBI组XIAP与Smac／DIABLO的表达和TUNEL（＋）细胞数均显著增加（P〈0．05）。结论：颅脑损伤可诱导XIAP与Smac／DIABLO的表达,提示XIAP对脑损伤后神经细胞继发凋亡损害起保护作用,而Smac／DIABLO则促进神经细胞的凋亡。     

Effect of photodynamic therapy and endostatin on human glioma xenografts in nude mice

The aim of this study was to investigate the effect of endostar (a recombinant human endostatin) and photodynamic therapy (PDT) on gliomas. To establish glioma xenografts, human U251 glioma cells were injected into the brain of nude mice. Mice with MRI-confirmed glioma received hematoporphyrin monomethyl ether (HMME)-mediated PDT, daily injection of endostar or their combination, respectively. After treatment, tumor volume, the expression of HIF-1α, VEGF-A and apoptosis marker, and animal survival were examined. PDT and endostar treatment can prolong survival. Changes in induction of apoptosis, tumor growth and survival were more significant in PDT + endostar group. After PDT, HIF-1α and VEGF-A expressions were markedly increased. After endostar treatment, HIF-1α and VEGF-A expressions were significantly reduced. PDT in combination with endostar can significantly inhibit the growth of glioma xenografts. This approach may represent a promising strategy in the treatment of glioma.     

PET-CT in der Strahlentherapie

Combining positron emission tomography (PET) and X-ray computed tomography (CT) with simultaneous acquisition may improve diagnostic accuracy in oncology. Moreover this combination holds considerable promise in radiotherapy. Metabolic information may be used in decision making in radiotherapy and in planning target volumes. Furthermore early evaluation of treatment efficacy becomes possible. New tracers for the assessment of tumour hypoxia or apoptosis in clinical routine are currently being developed. These tracers may yield high relevance in radiotherapy. Hybrid scanners facilitate patient handling and shorten the duration of acquisition. Furthermore fusion accuracy is optimal. Prospective studies have to be conducted to show that the new technology improves patient care in terms of efficiency and quality.