抗人DR4、DR5单克隆抗体诱导神经胶质瘤细胞凋亡的实验研究

目的：探讨抗死亡受体DR4、DR5单克隆抗体（mAb）FMU1．4、FMU1．5对3株神经胶质瘤细胞株U343（敏感株）、U138（部分敏感株）、U373（耐受株）的杀伤作用及机制。方法：采用流式细胞术、RT—PCR、免疫细胞化学法、MTT比色法、电泳、DNA倍体分析和Westem blot等方法。结果：DR5在U343高表达；DR4在U373低表达。U343对FMU1．5敏感并呈剂量依赖性、对FMU1．4部分敏感；U138对FMU1．5部分敏感，对FMU1．4耐受；U373对两种抗体耐受。结论：FMU1．4、FMU1．5能不同程度地诱导三株细胞凋亡，其机制与DR4、0115、细胞色素C和FLIP的表达有关。     

sTRAIL基因的克隆及其在大肠杆菌中的表达

克隆TRAIL基因的95-281位(sTRAIL)，构建表达载体，建立原核表达体系，优化诱导表达的条件。分离人外周血淋巴细胞，提取总RNA，RT-PCR，克隆sTRAIL的cDNA，构建原核表达载体，优化IPIG诱导的条件。结果：(1)克隆了TRAIL基因95-281位的cDNA，DNA测序结果与报道的一致。(2)构建了sTRAIL基因的原核表达载体，酶切结果与预期的一致。(3)转化宿主菌，优化IPIG诱导条件，发现3mmol/L，诱导3～4h表达最好。sTRAIL基因的克隆及表达为下游中试发酵及纯化奠定了上游的基础，也为研究TRAIL抗肿瘤的机制提供了可能。     

rhTRAIL对耐顺铂人肺腺癌细胞凋亡的影响

背景与目的TRAIL和TNF、Fas一样均属TNF蛋白超家族成员。研究表明,TNFα可用于克服某些肿瘤细胞的化疗耐药性,而一些化疗药物可上调死亡受体DR的表达,从而促进TRAIL诱导的细胞凋亡。本研究旨在探讨重组人可溶性肿瘤坏死因子相关凋亡诱导配体蛋白rhTRAIL对耐顺铂人肺腺癌细胞凋亡的影响。方法常规体外培养耐顺铂人肺腺癌细胞株A549/DDP,应用MTT比色法、DPA法、流式细胞术和激酶法,检测rhTRAIL对耐顺铂人肺腺癌细胞株A549/DDP细胞增殖的抑制活性及其诱导细胞凋亡的效应。结果单用rhTRAIL时,低剂量rhTRAIL(6.25、12.5、25.0μg/L)对A549/DDP细胞的生长抑制率和各项凋亡指数(细胞凋亡率、DNA片段化比率和Caspase3活性)均无明显影响,P>0.05,但当rhTRAIL浓度在50μg/L时,细胞生长抑制率、细胞凋亡指数、DNA片段化比率和Caspase3活性均明显增高,各达68.6%、(27.13±0.66)%、(37.4±2.0)%和0.117±0.011(P<0.05)。当3mg/LDDP和rhTRAIL联用时,12.5μg/L的rhTRAIL即可使A549/DDP细胞生长抑制率、细胞凋亡指数、DNA片段化比率和Caspase3活性明显增高,各达30.4%、(19.39±0.54)%、(17.3±4.1)%和0.138±0.009(P<0.05)。结论单用较高剂量的rhTRAIL可以诱导耐顺铂人肺腺癌细胞A549/DDP细胞凋亡。低剂量顺铂可以增强rhTRAIL诱导A549/DDP细胞凋亡的效应。rhTRAIL可望成为耐药性肺癌治疗的一种重要的生物制剂。     

透明颤菌血红蛋白基因在产TRAIL蛋白大肠杆菌中的克隆表达

为解决大肠杆菌高密度发酵生产TRA IL过程中的供氧矛盾,提高菌体的发酵密度,在大肠杆菌中引入透明颤菌血红蛋白基因(vgb)。聚合酶链反应(PCR)检验和CO差光谱法检验表明:vgb基因能够在C 600(pBV 220-TRA IL)中表达并受溶氧调控,重组菌CTV具有良好的遗传稳定性。3.7 L发酵罐实验表明:在同样的发酵条件下,含vgb基因的重组菌CTV的最高菌体密度为对照菌的1.64倍,达到50.6 g/L,乙酸积累为对照菌的55.6%,TRA IL蛋白产量提高了70%,达到2.8 g/L。     

TRAIL蛋白原核表达载体的构建及表达研究

目的 利用蛋白自剪切功能原核表达系统构建肿瘤坏死因子相关凋亡诱导配体（TRAIL）胞膜外段融合蛋白表达载体，并进行表达条件优化和初步纯化。方法 设计基因拼接引物，合成TRAIL基因胞膜外段双链cDNA序列，将其连接于克隆载体pMD18-T中；将酶切、纯化的TRAIL基因与经相同处理的载体pTWIN1相连接，转化感受态大肠杆菌JM109，筛选阳性重组子。将鉴定（酶切及序列分析）阳性的重组子质粒转人大肠埃希菌ER2566表达菌中，采用蛋白质SDS—PAGE电泳方法分析不同浓度诱导剂异丙基硫代-β-D-半乳糖苷（IPTG）、不同诱导温度、不同诱导时间下目的蛋白表达情况。结果 成功获得了包含TRAIL基因胞膜外段的双链cDNA序列，酶切及序列分析证实成功构建了TRAIL胞膜外段蛋白自剪切功能原核表达载体。采用0．3mmol／LIPTG、15℃诱导过夜（14～16h），目的蛋白获得较高表达量，且大部分为可溶性蛋白。结论 采用大肠埃希氏菌ER2566，TRAIL胞膜外段融合蛋白获得高表达，经简单后续处理即可获得不含任何额外氨基酸的可溶性目的蛋白。     

TRAIL联合紫杉醇对卵巢癌细胞凋亡影响的研究

目的:探讨TRAIL联合紫杉醇对卵巢癌3AO细胞株凋亡的影响,以进一步研究其诱导细胞凋亡的原理。方法:应用MTT法检测TRAIL和紫杉醇作用组的抑制率,并以流式细胞仪检测各组凋亡率。结果:亚毒剂量的TRAIL、紫杉醇及联合作用组致卵巢癌3AO细胞凋亡率分别为17.6%、16.1%、64.3%。单独应用组与联合应用组之间存在显著性差异(P<0.01)。结论:TRAIL在诱导卵巢癌细胞凋亡的同时,也显著提高了其对紫杉醇(taxol)的化疗敏感性。     

TRAIL及其死亡受体在宫颈癌组织中的表达和临床意义

目的:探讨宫颈癌组织中TRAIL及其死亡受体DR4的表达与宫颈病变之间的关系。方法:免疫组化SP法检测10例宫颈炎(排除HPV感染)、13例C INⅠ、15例C INⅡ~Ⅲ、36例宫颈癌(其中高分化和中分化27例、低分化9例)标本中的TRAIL及其死亡受体DR4的表达。结果:TRAIL在慢性宫颈炎、C INⅠ、C INⅡ~Ⅲ、宫颈癌组织中的表达逐渐减少,但各组比较无显著性差异,DR4在宫颈炎、C INⅠ、C INⅡ~Ⅲ的表达无明显趋向性,3组之间比较无显著性差异,宫颈癌组织中的表达减少,宫颈癌与宫颈炎、C INⅠ、C INⅡ~Ⅲ比较差异有显著性。TRAIL、DR4的表达随着宫颈癌分化程度的降低而降低,DR4表达差异有显著性,TRAIL表达差异无显著性。结论:TRAIL的表达与宫颈病变的程度无关,DR4的表达与宫颈癌的预后有关,TRAIL通过结合死亡受体发挥作用。     

Magnetic Iron Oxide Nanoparticles Mediated Gene Therapy for Breast Cancer-An In Vitro Study

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), also designated as Apo-2 ligand, is a typical member of the structurally related tumor necrosis factor (TNF) ligand family. It has been shown that TRAIL only induces the apoptosis of cancer cells rather than normal cells. This characteristic offers a new target for cancer treatment[1]. In fact, TRAIL gene has been successfully used for the treatment of cancer[2]. Viruses have been the common vectors used in TRAIL gene t…     

Magnetic Iron Oxide Nanoparticles Mediated Gene Therapy for Cancer An In Vitro Study

The aim of this study was to evaluate the feasibility and efficacy of using TRAIL gene to treat breast cancer mediated with a novel carrier - magnetic iron oxide nanoparticles (polyMAG-1000) coated with PEI. The magnetic iron oxide nanoparticles were used as gene carrier to transfect TRAIL gene into MCF-7 cells. The polyMAG-1000 without TRAIL gene was transfected into the tumor cells as negative control. TRAIL gene transfection with liposome as carrier served as positive control. The apoptosis of cells was detected with TUNEL method. The apoptosis ratio of tumor cells was measured with flow cytometry (FCM). It was found that the apoptosis occurred in the tumor cells after transfection of TRAIL gene mediated by both polyMAG-1000 and liposome. The apoptosis ratio in the group with polyMAG-1000 as gene carrier was (25.11±2.85) %, whereas it was (5.06±1.05) % in the control group with polyMAG-1000 (P＜0.01). The apoptosis ratio was as low as (18.31±2.44) % in the group with liposome as gene carrier (P＜0.05, as compared with the group with polyMAG-1000 as gene carrier). It is suggested that TRAIL gene may induce apoptosis in MCF-7 breast cancer cells. The magnetic iron oxide nanoparticles coated with PEI may be a potential gene carrier with high transfection efficacy for cancer gene therapy.     

Antibody-based fusion proteins to target death receptors in cancer

Ideally, an immunotoxin should be inactive ‘en route’, acquire activity only after tumor cell surface binding and have no off-target effects towards normal cells. In this respect, antibody-based fusion proteins that exploit the tumor-selective pro-apoptotic death ligands sFasL and sTRAIL appear promising. Soluble FasL largely lacks receptor-activating potential, whereas sTRAIL is inactive towards normal cells. Fusion proteins in which an anti-tumor antibody fragment (scFv) is fused to sFasL or sTRAIL prove to be essentially inactive when soluble, while gaining potent anti-tumor activity after selective binding to a predefined tumor-associated cell surface antigen. Importantly, off-target binding by scFv:sTRAIL to normal cells showed no signs of toxicity. In this review, we highlight the rationale and perspectives of scFv:TRAIL/scFv:sFasL based fusion proteins for cancer therapy.