构建携带胞嘧啶脱氨酶基因骨髓间充质干细胞及其对胶质瘤细胞的体外抑制作用

背景：转染胞嘧啶脱氨酶基因的骨髓间充质干细胞能有效地将化疗前药5-氟尿嘧啶转化成具有细胞毒性的化疗药物5-氟尿嘧啶,并在体外对胶质瘤细胞有显著的生长抑制作用。目的：探讨以骨髓间充质干细胞为基因治疗载体表达外源基因胞嘧啶脱氨酶基因对胶质瘤C6细胞增殖的影响。方法：分离、培养小鼠间充质干细胞,构建胞嘧啶脱氨酶基因与GFP联合的慢病毒载体,通过慢病毒包装法将胞嘧啶脱氨酶基因及GFP转染至小鼠骨髓间充质干细胞,获得稳定表达胞嘧啶脱氨酶基因及GFP的骨髓间充质干细胞,使其与胶质瘤C6细胞共培养,在培养液中加入5-氟胞嘧啶后应用流式细胞仪检测胞嘧啶脱氨酶基因对胶质瘤细胞的增殖影响。结果与结论：慢病毒介导的胞嘧啶脱氨酶基因及GFP基因成功转染小鼠骨髓间充质干细胞形成C57BL/6mMSC-codA/eGFP细胞,C57BL/6mMSC-codA/eGFP在5-氟胞嘧啶的作用下可引起胶质瘤C6细胞的明显凋亡,在5-氟胞嘧啶浓度为1×106μg/L条件下C6胶质瘤细胞凋亡率为60%（P〈0.05）。提示,C57BL/6mMSC-codA/eGFP可将5-氟胞嘧啶转化成5-氟尿嘧啶并对C6胶质瘤细胞生长有显著的限制作用甚至是致死效应。     

骨髓间充质干细胞-胞嘧啶脱氨酶/5-氟胞嘧啶自杀基因治疗系统的构建及效应

背景:体内研究已经证实骨髓间充质干细胞能够像神经干细胞一样在脑内迁移和整合,如果骨髓间充质干细胞用于系统途径移植成为可能,将会显著简化移植的步骤.目的:构建含胞嘧啶脱氨酶(CD)基因的重组表达质粒pEGFP-N3-CD,用脂质体Lipofectamine2000转染大鼠骨髓间充质千细胞,体外观察CD基因的表达及BMSCs-CD/5-氟胞嘧啶自杀基因治疗系统对C6胶质瘤细胞的杀伤作用.方法:构建pEGFP-N3-CD质粒,酶切、DNA测序鉴定.全骨髓贴壁法分离培养骨髓间充质干细胞,脂质体Lipofectamine2000介导重组表达质粒pEGFP-N3-CD转染大鼠骨髓间充质干细胞,G418筛选培养获取阳性克隆(BMSCs-CD细胞),免疫细胞化学染色检测BMSCs-CD细胞的CD基因蛋白表达.Transwell小室共培养BMSCs-CD细胞和C6胶质瘤细胞,24 h后加入前体药物5-氟胞嘧啶,72 h后TUNEL、MTT、流式细胞术检测C6胶质瘤细胞的凋亡情况.结果与结论:构建的重组表达质粒pEGFP-N3-CD含完整的CD基因序列,CD基因转染至骨髓间充质干细胞并在基因及蛋白水平有完整表达.BMSCs-CD和C6胶质瘤细胞体外共培养条件下,C6胶质瘤的凋亡率呈剂量依赖性,与对照组相比差异有显著性意义(P<0.01).结果提示体外共培养条件下,BMSCs-CD/5-氟胞嘧啶自杀基因治疗系统对C6胶质瘤细胞生长有显著的抑制作用.     

Lipofectamine介导胞嘧啶脱氨酶基因转染鼠骨髓间充质干细胞

背景:自杀基因独有的旁观者效应,可显著提供肿瘤细胞杀伤效果,同时还与放射治疗、免疫基因治疗联合应用,并克服了基因转导效率低的缺陷.胞嘧啶脱氨酶即可产生强大的旁观者效应.目的:观察脂质体介导真核表达载体胞嘧啶脱氨酶基因转染鼠骨髓间充质干细胞的效果及其基因表达.设计、时间及地点:细胞学基因水平体外实验,于2007-05/12在大连理工大学干细胞与组织工程研发中心完成.材料:SPF级C57BL纯系小鼠6只,体质量18-20 g,用于骨髓间充质干细胞的分离培养.连接产物转化感受态大肠杆菌DH5a由大连理工大学干细胞与组织工程研发中心提供.Lipofectamine~(TM)2000脂质体为Invitrogen产品.方法:取连接产物转化感受态大肠杆菌DH5a,提取质粒DNA,对质粒plRES2-cGFP1-CD进行Xhol和BamHI双酶切,用于转染.取小鼠双侧下肢股骨和胫骨,贴壁法分离纯化骨髓间充质干细胞,传至第3代制成单细胞悬液,加入荧光标记的CD44,CD45,CD90,CD105抗体后,采用Lipofectamine~(TM)2000介导法转染第3代鼠骨髓间充质干细胞.主要观察指标:重组质粒的鉴定,流式细胞仪检测鼠骨髓间充质干细胞表面标记表达,荧光倒置显微镜观察细胞转染36,48 h后胞嘧啶脱氨酶基因的表达.结果:质粒plRES2-AcGFP1-CD酶切产物经琼脂糖凝胶电泳后,于1.0～1.5 kb处有1条带出现,符合胞嘧啶脱氨酶基因长度.流式细胞仪检测显示细胞表面标记CD45呈阴性,CD44,CD90,CD105呈阳性.plRES2-AcGFP1-CD基因转染36 h后,荧光倒置相差显微镜下可见小鼠骨髓间充质干细胞有绿色荧光蛋白表达,48 h后细胞仍有荧光表达,且强度明显增强.结论:脂质体介导的胞嘧啶脱氨酶基因在鼠骨髓间充质干细胞中成功表达,于转染48 h后达峰值.     

携带CXCR4基因慢病毒载体转染大鼠骨髓间充质干细胞的体外实验

背景：间充质干细胞在体内归巢主要调控因子是CXCR4,如何提高干细胞自身CXCR4的表达量是调节干细胞体内靶器官归巢能力的关键。
　　目的：构建CXCR4或GFP基因慢病毒表达载体,并观察其对骨髓间充质干细胞自身生长特性及分泌功能的影响。
　　方法：骨髓间充质干细胞应用慢病毒载体转染系统转染CXCR4基因达到过表达,同时单独转GFP基因作为对照。通过荧光显微镜、RT-PCR、免疫蛋白印迹方法验证病毒转染效率;流式细胞技术测定骨髓间充质干细胞的增殖、凋亡情况;Western Blot法测定间充质干细胞培养基上清中分泌蛋白及细胞因子变化。
　　结果与结论：慢病毒转染系统可以安全、有效地转染CXCR4基因或GFP基因到骨髓间充质干细胞。流式细胞仪检测显示过表达CXCR4的骨髓间充质干细胞增殖能力、生存能力加强,凋亡细胞减少(P<0.05);细胞上清蛋白分析提示过表达CXCR4后,骨髓间充质干细胞培养上清内出现很多的蛋白因子升高(P<0.05),其中大多数对细胞自身复制及免疫调节有益。结果表明慢病毒转染是一种安全高效的基因修饰手段,可以通过CXCR4基因修饰的方法提高骨髓间充质干细胞的生存能力、降低凋亡率,调节细胞保护性因子及免疫调节因子的分泌功能。     

凝血因子Ⅸ基因敲除对小鼠骨髓间充质干细胞生物学特性无直接影响

背景：凝血因子Ⅸ基因敲除有可能通过影响造血系统的稳定性从而影响骨髓造血微环境中骨髓间充质干细胞的生物学特性目的：鉴定凝血因子Ⅸ基因敲除C57BL/6J-F9tm1.Dws小鼠骨髓间充质干细胞的生物学特征。方法：采用改进的全骨髓贴壁细胞分离法分离培养凝血因子Ⅸ基因敲除C57BL/6J-F9tm1.Dws小鼠骨髓间充质干细胞,流细胞术鉴定其表面标记的表达,以特殊诱导培养基诱导骨髓间充质干细胞干向成骨细胞,脂肪细胞,软骨细胞方向分化。结果与结论：分离的骨髓间充质干细胞形态均一为梭形,增殖能力和自我更新能力强。流式细胞术检测细胞表面标识CD44CD56、CD73、CD90、CD105、CD106、CD166及CD271表达呈阳性,CD34、CD11b表达呈阴性。分离的骨髓间充干细胞具有向成骨细胞,脂肪细胞,软骨细胞方向分化的能力。说明凝血因子Ⅸ基因敲除C57BL/6J-F9tm1.Dws小鼠的骨间充质干细胞仍具备良好的干细胞的生物学特性,初步确定,凝血因子Ⅸ基因敲除对骨髓间充质干细胞的生物学特性并直接影响。     

pIRES2-AcGFP1-CD真核表达载体在骨髓间充质干细胞中的表达

背景：骨髓间充质干细胞在体外易分离和扩增，还易于外源基因的转入及表达，是一种理想的治疗性细胞和基因治疗的靶细胞。目的：观察脂质体介导胞嘧啶脱氨酶基因转染兔骨髓间充质干细胞及其表达。设计、时间及地点：单一样本观察的细胞基因工程实验，于2006—03／2007—04在大连理工大学干细胞与组织工程研发中心完成。材料：5月龄新西兰大自耳兔用于骨髓间充质干细胞的分离培养。方法：采用密度梯度离心法分离骨髓间充质干细胞。以大肠杆菌JM109基因组DNA为模板，用PCR方法获得目的基因片段，定向克隆至载体pMD19-T，限制性内切酶消化鉴定、基因测序后，构建pIRES2-AcGFP1-CD真核表达质粒。酶切鉴定后，采用Lipofectamine 2000介导胞嘧啶脱氨酶基因转染骨髓间充质干细胞。主要观察指标：倒置荧光显微镜下观察绿色荧光蛋白表达情况。结果：成功克隆了胞嘧啶脱氨酶基因，基因测序结果同Genbank中公布的序列一致。将胞嘧啶脱氨酶基因亚克隆到pIRES2-AcGFP1质粒上，构建了pIRES2-AcGFP1-CD真核表达载体。利用脂质体介导法将胞嘧啶脱氨酶基因转染骨髓间充质干细胞，24h后在倒置荧光显微镜下观察到绿色荧光蛋白的表达。结论：pIRES2-AcGFP1-CD真核表达载体已成功转入骨髓间充质干细胞中，说明骨髓间充质干细胞有望成为胞嘧啶脱氨酶基因治疗中的理想载体。     

pIRES2-AcGFP1-CD真核表达载体构建及其在骨髓间充质干细胞中的表达

背景:骨髓间充质干细胞在体外易分离和扩增,还易于外源基因的转入及表达,在人类医学上被认为是一种理想的治疗性细胞和基因治疗中的靶细胞.目的:探讨脂质体介导胞嘧啶脱氨酶基因转染兔骨髓间充质干细胞及其基因的表达.设计:单一样本观察.单位:大连市干细胞与组织工程研发中心,大连医科大学基础医学院生化室.材料:实验于2006-03/2007-06在大连市干细胞与组织工程研发中心及大连医科大学基础医学院生化室完成.新西兰大白耳兔,5月龄,雌雄不拘,体质量2.0～2.5 kg.方法:以大肠杆菌JM109基因组DNA为模板,用PCR方法获得目的基因片段,定向克隆至载体pMD19-T,限制性内切酶消化鉴定、基因测序后,构建pIRES2-AcGFP1-CD真核表达质粒.同时对兔骨髓间充质干细胞取材、培养、鉴定.真核表达质粒经酶切鉴定后,采用Lipofectamine 2000介导法转染经过鉴定的兔骨髓间充质干细胞.并于转染后24 h 在倒置荧光显微镜下观察绿色荧光蛋白的表达.主要观察指标:表达载体的构建及基因转染骨髓间充质干细胞鉴定.结果:实验克隆出胞嘧啶脱氨酶基因,并将其与带荧光的真核表达载体pIRES2-AcGFP1连接.经转染兔骨髓间充质干细胞24 h 后,在倒置荧光显微镜488 nm 蓝光激发下观察,pIRES2-AcGFP1-CD组和pIRES2-AcGFP1空载体组均可见细胞发出绿色荧光,未经转染的细胞未见发出绿色荧光,说明胞嘧啶脱氨酶基因成功转染了骨髓间充质干细胞.结论:骨髓间充质干细胞有望成为胞嘧啶脱氨酶基因治疗中的理想载体.     

pIRES2-AcGFP1-CD真核表达载体构建及其在骨髓间充质干细胞中的表达

背景：骨髓间充质干细胞在体外易分离和扩增，还易于外源基因的转入及表达，在人类医学上被认为是一种理想的治疗性细胞和基因治疗中的靶细胞。 目的：探讨脂质体介导胞嘧啶脱氨酶基因转染兔骨髓间充质干细胞及其基因的表达。 设计：单一样本观察。 单位：大连市干细胞与组织工程研发中心，大连医科大学基础医学院生化室。 材料：实验于2006—03／2007—06在大连市干细胞与组织工程研发中心及大连医科大学基础医学院生化室完成。新西兰大白耳兔，5月龄，雌雄不拘，体质量2．0～2．5kg。 方法：以大肠杆菌JM109基因组DNA为模板，用PCR方法获得目的基因片段，定向克隆至载体pMD19-T，限制性内切酶消化鉴定、基因测序后，构建pIRES2-AcGFP1-CD真核表达质粒。同时对兔骨髓间充质干细胞取材、培养、鉴定。真核表达质粒经酶切鉴定后，采用Lipofectamine2000介导法转染经过鉴定的兔骨髓间充质干细胞。并于转染后24h在倒置荧光显微镜下观察绿色荧光蛋白的表达。主要观察指标：表达载体的构建及基因转染骨髓间充质干细胞鉴定。 结果：实验克隆出胞嘧啶脱氨酶基因，并将其与带荧光的真核表达载体pIRES2-AcGFP1连接。经转染兔骨髓间充质干细胞24h后，在倒置荧光显微镜488am蓝光激发下观察，pIRES2-AcGFP1-CD组和pIRES2-AcGFP1空载体组均可见细胞发出绿色荧光，未经转染的细胞未见发出绿色荧光，说明胞嘧啶脱氨酶基因成功转染了骨髓间充质干细胞。 结论：骨髓间充质干细胞有望成为胞嘧啶脱氨酶基因治疗中的理想载体。     

系统性红斑狼疮小鼠骨髓间充质干细胞的成骨、成脂分化能力下降

背景：系统性红斑狼疮患者的骨髓间充质干细胞与正常人相比是否有不同,相关报道较少。 目的：对比系统性红斑狼疮模型小鼠与正常小鼠的骨髓间充质干细胞多向分化能力的差别。 方法：分离培养系统性红斑狼疮模型小鼠与C57BL小鼠的骨髓间充质干细胞（对照组）,分别进行成骨、成脂诱导分化,观察两种小鼠的骨髓间充质干细胞的分化能力。 结果与结论：C57BL小鼠的骨髓间充质干细胞经传代后,为长梭形,呈均匀分布生长;系统性红斑狼疮模型小鼠的骨髓间充质干细胞表现为生长缓慢,细胞相对C57BL小鼠要少一些。经过成骨诱导显示系统性红斑狼疮模型小鼠的钙结节和钙盐明显少于对照组,PCR检测成骨基因Runx2,碱性磷酸酶,骨钙素表达也明显下降。经过成脂诱导显示系统性红斑狼疮模型小鼠的脂滴明显少于对照组,PCR检测成脂基因PPARγ2,脂蛋白酯酶表达也明显下降。说明系统性红斑狼疮模型小鼠的骨髓间充质干细胞成骨与成脂能力都低于C57BL小鼠,系统性红斑狼疮模型小鼠的骨髓间充质干细胞的多向分化能力受损。     

Nesprin基因RNAi慢病毒载体的构建

背景:Nesprin蛋白缺失将影响细胞骨架组织和动态平衡,引起细胞骨架刚性丧失或导致细胞过早成熟老化,其对间充质干细胞的作用如何?目的:构建Nesprin蛋白siRNA慢病毒载体,并转染骨髓间充质干细胞.方法:针对Nesprin靶基因序列设计并合成4对miRNA oligo,将4种miRNA干扰质粒转入大鼠血管平滑肌细胞,筛选最有效干扰序列;将最佳干扰序列和pDONR221载体进行重组反应,获得含干扰序列的入门载体,再将入门载体和慢病毒表达目的载体pLenti6/V5-DEST进行重组反应,获得含干扰序列的慢病毒表达载体,转染包装细胞293T细胞,包装慢病毒,以293T细胞GFP蛋白水平测定病毒滴度.慢病毒转染大鼠骨髓间充质干细胞.结果与结论:测序证实合成的4对miRNA oligo正确,RT-PCR和western-blot筛选出最佳干扰miRNA质粒为SR-3,成功构建了Nesprin siRNA的慢病毒载体LV-siNesprin.包装慢病毒,浓缩病毒悬液的活性滴度为106 TU/mL.慢病毒成功了转染骨髓间充质干细胞细胞.     

Sustained transduction of ocular cells with a bovine immunodeficiency viral vector

Human immunodeficiency viral (HIV) vectors mediate long-term transduction of many types of nondividing cells in vivo. Bovine immunodeficiency virus (BIV) is a lentivirus that shares many characteristics with HIV, but does not cause human disease. In this study, we investigated the potential of BIV vectors for ocular gene therapy. An enhanced green fluorescent protein (eGFP)-encoding reporter gene was packaged in recombinant BIV vector (BIV.eGFP). Adult C57BL/6 mice were given an intravitreous (5 x 10(4) or 5 x 10(5) transducing units [TU]) or subretinal (5 x 10(5) TU) injection of BIV.eGFP and then GFP expression was assessed at several time points. In vivo examinations of mice showed that subretinal injection of BIV.eGFP resulted in strong expression of GFP from the first examination at 1 week through the final examination at 20 weeks. Only a few mice that received intravitreous injection of BIV.eGFP showed GFP expression by ocular examinations until 11-12 weeks, when most showed small areas of expression. Postmortem examinations showed prominent GFP expression in retinal pigmented epithelial (RPE) cells throughout the region of subretinal injection of vector, although occasional negatively staining RPE cells were scattered among the much more numerous, brilliantly staining cells. Ciliary epithelial cells frequently expressed GFP, as did occasional Müller cells and rarely other retinal cells. The expression was stable from the first time point (2 weeks) to the last (20 weeks). Postmortem examination of eyes given an intravitreous injection of BIV.eGFP showed transduction of cells in the corneal endothelium and a few scattered retinal cells. There was no evidence of inflammation or toxicity in any eyes. These data show that BIV vectors mediate rapid and sustained transduction of RPE cells, suggesting that they may be useful for ocular gene therapy targeting RPE cells.     

Mutation of Escherichia coli cytosine deaminase significantly enhances molecular chemotherapy of human glioma

Combined treatment using adenoviral (Ad)-directed enzyme/prodrug therapy and radiation therapy has the potential to become a powerful method of cancer therapy. We have developed an Ad vector encoding a mutant bacterial cytosine deaminase (bCD) gene (AdbCD-D314A), which has a higher affinity for cytosine than wild-type bCD (bCDwt). The purpose of this study was to evaluate cytotoxicity in vitro and therapeutic efficacy in vivo of the combination of AdbCD-D314A with the prodrug 5-fluorocytosine (5-FC) and ionizing radiation against human glioma. The present study demonstrates that AdbCD-D314A infection resulted in increased 5-FC-mediated cell killing, compared with AdbCDwt. Furthermore, a significant increase in cytotoxicity following AdbCD-D314A and radiation treatment of glioma cells in vitro was demonstrated as compared to AdbCDwt. Animal studies showed significant inhibition of subcutaneous or intracranial tumor growth of D54MG glioma xenografts by the combination of AdbCD-D314A/5-FC with ionizing radiation as compared with either agent alone, and with AdbCDwt/5-FC plus radiation. The results suggest that the combination of AdbCD-D314A/5-FC with radiation produces markedly increased cytotoxic effects in cancer cells in vitro and in vivo. These data indicate that combined treatment with this novel mutant enzyme/prodrug therapy and radiotherapy provides a promising approach for cancer therapy.     

Suicidal gene therapy in the effective control of primary human hepatocellular carcinoma as monitored by noninvasive bioimaging

Hepatocellular carcinoma (HCC) is usually refractory to the available treatments. For cancer gene therapy purposes, real-time imaging of therapeutic gene expression is of great importance because there are multiple factors that modulate the therapeutic gene expression in a complex tumor microenvironment. As a consequence, multiple doses of therapeutic viral vectors may be required for improved efficacy. In the present study, the luciferase reporter gene and the yeast cytosine deaminase (yCD) genes were bicistronically expressed using the foot-and-mouth disease virus 2A peptide under the regulation of the cytomegalovirus (CMV) promoter. The effectiveness of the yCD/5-FC (5-fluorocytosine) killing efficacy mediated by the herpes simplex virus type 1 (HSV-1) amplicon viral vector was shown using HCC and non-HCC cell lines in vitro. In addition, in vivo experiment also showed tumor regression of a primary HCC 26-1004 tumor xenograft in tumor expressing high levels of the yCD gene (as determined by noninvasive imaging) after intratumoral injection of 1.5 × 10(6)?TU HGCX-L2C HSV-1 amplicon viral vector and 5-FC administration. The HSV-1 amplicon viral vector coupled with the yCD/5-FC prodrug activated suicide gene could potentially be of use in clinical gene therapy for HCC.     

Wt—p53／p16基因联合CD／5-FC系统对U251细胞化疗效果的研究

[目的]研究p53、p16基因联合胞嘧啶脱氨酶（CD）／5-氟胞嘧啶（5-FC）治疗神经胶质瘤的可行性。[方法]体外试验以Fe3O4磁性纳米颗粒（Fe3O4 magneticna noparticles,Fe3O4 MNP）为基因载体将质粒pCDNA3．1-p16、pYD5-p53,及pCMVCD转染入U251人胶质瘤细胞,给以不同浓度的5-FC,以MTT法检测细胞生长抑制率。[结果]成功以Fe3O4MNP为载体将wt-p53、wt-p16及CD基因转染U251细胞,并稳定表达。体外转染wt-p53、wt-p16基因都能明显提高CD／5-FC人对胶质瘤细胞的化疗效果。[结论]基于Fe3O4磁性纳米基因载体的p53、p16基因和CD／5-FC系统的联合基因治疗可作为临床上优化自杀基因治疗方案的一种可能选择,可以明显提高治疗效果。     

逆转录病毒介导Fcy::Fur融合基因联合5-FC治疗胶质瘤的体内试验研究

目的构建含融合自杀基因Fcy::Fur重组逆转录病毒,用自杀基因治疗系统Fcy::Fur/5-氟胞嘧啶(5-FC)对裸鼠胶质瘤进行体内抑瘤作用的实验研究。方法扩增Fcy::Fur基因并构建Fcy::Fur基因重组逆转录病毒载体;载体转染包装细胞获得高滴度病毒并转染鼠胶质瘤细胞C6,筛选并鉴定阳性转基因克隆;构建裸鼠荷胶质瘤动物模型,腹腔注射5-FC,观察裸鼠肿瘤重量变化及电镜、流式细胞仪(FCM)检测肿瘤的凋亡。结果PCR法扩增出全长Fcy::Fur基因,经测序证实序列正确;构建了PLXSN-Fcy::Fur逆转录病毒载体,载体转染包装细胞PT67,获得滴度为3.5×106CFU/mL的逆转录病毒;转染C6获转基因阳性克隆C6-Fcy::Fur,检测C6-Fcy::Fur有Fcy::Fur基因的mRNA表达;裸鼠前肢背部接种转基因细胞,成瘤后腹腔注射5-FC,转基因肿瘤的生长较对照组明显抑制。FCM法检测到凋亡峰,电镜观察到转基因肿瘤细胞有凋亡小体。结论AdE1CMVCD与5-FC联合在体内对胶质瘤有明显的抑制作用,为临床胶质瘤基因治疗提供了可靠的理论及应用依据。     

Fractionated radiation therapy in combination with adenoviral delivery of the cytosine deaminase gene and 5-fluorocytosine enhances cytotoxic and antitumor effects in human colorectal and cholangiocarcinoma models

Radiosensitization of human gastrointestinal tumors by 5-fluorouracil (5-FU) has been studied in vitro and clinically in human cancer therapy trials. The bacterial enzyme cytosine deaminase (CD) converts the nontoxic prodrug 5-fluorocytosine (5-FC) into 5-FU. Human colon cancer cells stably expressing CD have been shown by other investigators to be sensitized to radiation following treatment with 5-FC. We previously used an adenoviral vector under control of the cytomegalovirus promoter (AdCMVCD) encoding the CD gene in combination with 5-FC and a single fraction of radiation exposure to enhance cytotoxicity to human cholangiocarcinoma cells in vitro and in vivo. The purpose of this study was to determine whether AdCMVCD infection and 5-FC with multiple fraction low-dose radiotherapy results in enhanced cytotoxicity. In the present study, we utilized AdCMVCD and 5-FC with single fraction radiotherapy to demonstrate enhanced cytotoxicity to WiDr human colon carcinoma cells in vitro. Additionally, we tested this gene therapy/prodrug treatment strategy employing a fractionated radiation dosing schema in animal models of WiDr colon carcinoma and SK-ChA-1 cholangiocarcinoma. A prolonged WiDr tumor regrowth delay was obtained with AdCMVCD infection in combination with systemic delivery of 5-FC and fractionated external beam radiation therapy compared with control animals treated without radiation, without 5-FC, or without AdCMVCD. The results of treatment with AdCMVCD + 5-FC + radiation therapy to cholangiocarcinoma xenografts were equivalent to those obtained with systemic 5-FU administration + radiation. Thus, the use of AdCMVCD can be effectively combined with clinically relevant 5-FC and radiation administration schemes to achieve enhanced tumor cell killing and increased control of established tumors of human gastrointestinal malignancies.     

YCD/5-FC自杀基因治疗系统对K562B白血病细胞杀伤作用的小鼠体内实验研究

目的　了解酵母菌胞嘧啶脱氨酶 5 氟胞嘧啶 (YCD 5 FC)系统在体内对转基因高致瘤性K5 6 2细胞 (K5 6 2B细胞 )的杀伤效应。方法　以高滴度逆转录病毒转染K5 6 2B细胞并筛选出阳性转染克隆YCD K5 6 2B ;12只SCID小鼠分为治疗及对照组 ,在小鼠左右两侧近前肢处腹部皮下注射YCD K5 6 2B及K5 6 2B细胞 ,成瘤后治疗组腹腔注射 5 0 0mg kg 5 FC共 10d ,对照组腹腔注射生理盐水 ,观察瘤体相对体积变化及病理变化。结果　瘤细胞接种第 2 1天 ,瘤体相对体积分别为 :YCD K5 6 2B +5 FC组 2 .92 2± 0 .5 81,YCD K5 6 2B +生理盐水组 2 4.434± 4.790 ,K5 6 2B +5 FC组 2 2 .70 1± 2 35 0 ,K5 6 2B +生理盐水组 2 4.46 0± 1.6 70 ;YCD K5 6 2B +5 FC组与YCD K5 6 2B +生理盐水组相比差异非常显著 (P =0 0 0 0 1) ,K5 6 2B +5 FC组及K5 6 2B +生理盐水组相比 ,差异无显著性 (P =0 .0 96 ) ,表明 5 FC对转YCD基因的K5 6 2B白血病细胞有明显的杀伤效应 ,而对未转基因细胞的生长无影响 ;YCD K5 6 2B +5 FC组瘤体于瘤细胞接种后第 12～第 15天 (5 FC治疗的第 3～第 6天 )有所缩小 (最小的相对体积为 0 .6 81) ,病理检查可见 5 FC治疗组瘤体有以小动脉血管为中心的坏死。结论　YCD 5 FC系统在体内对转YCD