氟胞嘧啶/胞嘧啶脱氨酶自杀基因疗法结合热休克蛋白-多肽复合物治疗小鼠胃癌

目的；研究氟胞嘧啶／胞嘧啶脱氨酶（5－FC／CD）基因疗法与热休克蛋白－多肽复合物（FSP70－PC）免疫疗法联合抗肿瘤效果。方法；将携带CD基因的重组腺病毒注射到小鼠MFC瘤体内，腹腔注射5－FC，同时皮下接种HSP70－PC。结果；经联合治疗后，70％荷瘤小鼠肿瘤体答缩小，消退，小鼠存活期延长，细胞毒T淋巴细胞（CTL）杀伤活性增高，CD4^ 及CD^8 T细胞浸润明显。结论：5－FC／CD基因疗法结合HSP－PC免疫疗法抗小鼠MFC瘤作用显著，具有临床应用前景。     

联合自杀基因与IL-2基因转移疗法的抗肿瘤效果及其抗肿瘤免疫应答的诱导作用

单用自杀基因疗法或单用细胞因子基因疗法抗肿瘤效果不理想,本研究中我们观察了大肠杆菌胞嘧啶脱胺酶(CD)基因与白细胞介素2(IL-2)基因联合转移对荷瘤小鼠的治疗效果及其对抗肿瘤免疫的诱导作用。复制荷瘤小鼠模型后在荷瘤部位注射表达CD基因的重组腺病毒(AdCD)及表达小鼠IL-2基因的重组腺病毒(AdIL2),并连续10天、每天1次腹腔注射5氟胞嘧啶(5FC)对荷瘤小鼠进行治疗。结果表明,AdCD/5FC/AdIL2联合基因治疗能显著抑制荷瘤小鼠皮下肿瘤的生长,并明显延长其生存期(P<0.01)。联合基因治疗组小鼠肿瘤细胞发生明显的坏死,瘤内及瘤周有大量的炎性细胞浸润,瘤内CD4~ 和CD8~ T细胞明显增加,脾细胞NK和CIL杀伤活性明显高于单用AdCD/5FC、对照病毒AdLacZ/5FC或PBS组。实验结果表明,联合应用自杀基因与细胞因子基因治疗可更有效诱导机体的抗肿瘤免疫反应,从而更显著地抑制荷瘤小鼠肿瘤的生长。     

p16基因重组质粒的构建及其对人肺癌细胞的抑制作用

表达大肠杆菌胞嘧啶脱胺酶(CD)基因的重组腺病毒AdCD体外转染小鼠黑色素瘤细胞B16F10,结果显示转染了CD基因的B16F10细胞对5-氟胞嘧啶(5FC)的敏感性显著提高.将经AdCD/5FC系统处理的B16F10细胞上清倍比稀释后.加至野生型B16F10细胞中,发现当上清仅占6.25%时即可对野生型B16F10细胞发挥明显的杀伤作用,提示AdCD/5FC介导的旁观者效应可能是通过5FC经CD酶代谢产生的毒性产物扩散而实现的.本实验还观察了CD基因体内转染后的杀伤效果,荷瘤小鼠经注射AdCD并连续10天给予5FC治疗后,与PBS、对照病毒AdLacZ/5FC治疗小鼠比较,小鼠肿瘤生长明显受到抑制,小鼠存活期明显延长.     

5-氟胞嘧啶对表达胞嘧啶脱氨酶的人肾母细胞瘤裸鼠异种移植瘤的疗效

目的　以人肾母细胞瘤裸鼠异种移植瘤模型 ,研究 5 氟胞嘧啶 (5 FC)作为原药对表达胞嘧啶脱氨酶 (CD)的肾母细胞瘤治疗 (以下简称CD/ 5 FC)的作用。方法　 1例低分化肾母细胞瘤组织 ,移植于无胸腺BALB/c裸鼠 ,经连续传代 ,建立了人肾母细胞瘤异种移植瘤模型。以腺病毒为载体 ,分别建立CD基因 (Ad/CMV CD)和lac基因 (Ad/CMV lac)的表达载体。瘤内注射基因表达载体 ,使基因转导入肿瘤细胞。用RT PCR检测转导基因在瘤细胞内的表达。腹腔注射 5 FC ,5 0 0mg·kg-1·d-1,连续 10d ,观察移植瘤生长情况。结果　经 5 FC治疗的小鼠 ,表达lac基因的移植瘤生长情况与未转导基因的移植瘤并无两样 ;表达CD基因的移植瘤生长则受到显著抑制。根据接种肿瘤后 8周的肿瘤重量 ,5 FC治疗对CD基因转导的移植瘤生长抑制率为 6 5 %。病理检查可见瘤细胞坏死 ,细胞器出现空泡。结论　在瘤内转导CD基因的基础上施以 5 FC治疗 ,对人肾母细胞瘤裸鼠移植瘤有明显疗效。     

ADU-S100/多柔比星原位疫苗在弥漫大B细胞淋巴瘤中的作用及机制研究

目的探讨ADU-S100/多柔比星原位疫苗在弥漫大B细胞淋巴瘤中的抗肿瘤作用及相关机制。方法选择6周龄雌性BALB/c小鼠, 采用小鼠B细胞淋巴瘤A20细胞株构建小鼠B细胞淋巴瘤双侧皮下肿瘤模型, 采用随机数字表法将皮下荷瘤小鼠随机分为未治疗组(不接受任何治疗)、ADU-S100原位疫苗治疗组(瘤内注射干扰素基因刺激因子激动剂ADU-S100)、多柔比星原位疫苗治疗组(瘤内注射多柔比星)和ADU-S100/多柔比星原位疫苗治疗组(瘤内注射ADU-S100+多柔比星), 每组5只。将荷瘤小鼠右侧肿瘤定义为近端肿瘤, 左侧肿瘤定义为远端肿瘤, 仅对近端肿瘤进行瘤内药物注射治疗, 远端肿瘤不处理。肿瘤接种后第23天, 采用流式细胞术检测各组小鼠脾脏中CD11c+树突细胞(DC)、CD8+ CD11c+ DC和CD80+ CD11c+ DC亚群的比例。采用A20肿瘤细胞裂解物体外刺激各组小鼠的脾细胞, 应用流式细胞术检测各原位疫苗治疗组CD8+ T细胞中5’’-乙炔基-2’’脱氧尿嘧啶核苷阳性(EdU+)细胞和肿瘤坏死因子α阳性(TNF-α+)细胞的比例, 并使用乳酸脱氢酶(LDH)细胞毒性检...     

肿瘤细胞裂解物联合IL-2预防黑色素瘤发生并抑制肿瘤生长的免疫机制

目的 探讨肿瘤细胞裂解物（TCL）联合IL-2对黑色素瘤的预防和抑制作用及其免疫机制。方法 超声破碎仪制备B16F10黑色素瘤细胞TCL。24只C57BL/6小鼠随机分为四组,分别予PBS、IL-2、TCL及TCL+IL-2预防性免疫3周,第4周对侧植瘤。观察小鼠出瘤时间及肿瘤大小,连续采集外周血行流式细胞术动态监测CD4+T及CD8+T细胞。流式细胞术及免疫组织化学检测小鼠脾脏及肿瘤组织CD4+T及CD8+T细胞。结果 TCL+IL-2组预防性免疫后明显延迟了小鼠的出瘤时间（P=0.034）,且肿瘤体积（P=0.023）及瘤重（P=0.0015）也明显小于对照组。流式细胞术动态监测结果提示TCL+IL-2组及单纯TCL组外周血中CD8+T细胞较对照组均有明显上升（P=0.0016, P=0.012）。TCL+IL-2组的CD4+T细胞在植瘤后较对照组有所下降（P=0.0089）。脾脏及肿瘤组织中CD4+T细胞及CD8+T细胞的结果与外周血中的表达趋势相同。结论 TCL联合IL-2的肿瘤疫苗通过激活CD8+T细胞途径,预防小鼠黑色素瘤的发生并抑制肿瘤生长。     

腺病毒介导CD/5FC“自杀基因”疗法对人肝癌裸鼠和小鼠结肠腺癌的治疗作用研究

“自杀基因”疗法应用于肿瘤治疗时,通常是在肿瘤局部直接转染“自杀基因”,以期达到在肿瘤局部发挥抗肿瘤作用而避免全身毒性.在本实验中,我们观察了腺病毒介导的“自杀基因”疗法(CD/5FC系统)对人肝细胞癌SMMC-7721及小鼠结肠腺癌CT26的生长抑制作用,证实了腺病毒介导的CD/5FC系统在体外能杀伤人肝癌细胞SMMC-7721,并且能明显地抑制裸鼠SMMC-7721肿瘤模型的生长,对小鼠的结肠腺癌CT26也有一定的治疗作用.同时观察了以AFP启动子驱动的CD基因合并5FC的使用对AFP阳性肝癌细胞的特异性杀伤作用,证实了以肝癌特异启动子驱动的CD基因能在高表达AFP的肝癌细胞HepG2中特异表达,合并5FC的使用能在体外特异地杀伤HepG2细胞.这一组织特异性的“自杀基因”系统能特异地抑制高水平分泌AFP的人肝细胞癌裸鼠模型7721AFP( )的生长,上述研究结果表明,腺病毒介导的CD/5FC系统是一个有效的治疗方案,组织特异性的表达调控更能体现该疗法的实用价值.     

CD自杀基因联合淋巴细胞趋化因子基因疗法的肿瘤治疗作用及免疫机理研究

本研究以腺病毒作为载体,将大肠杆菌胞嘧啶脱氨酶(CD)基因与小鼠淋巴细胞趋化因子(Ltn)基因体内联合转染,观察了其抗肿瘤效应并分析了免疫机理.小鼠皮下接种结肠腺癌CT26细胞后3天,肿瘤局部注射表达Ltn的重组腺病毒AdLtn和表达CD的重组腺病毒AdCD,然后连续10天给予5一氟胞嘧啶(5-FC)300mg/kg进行治疗,结果表明,联合治疗组荷瘤小鼠皮下肿瘤结节的生长受到明显抑制,小鼠存活期明显长于单用AdLtn治疗组或单用AdCD/5-FC治疗组.经联合治疗后小鼠脾细胞的NK活性和对(37结肠腺癌细胞的CTL杀伤活性明显增强.瘤体细胞FACS分析结果表明,经联合基因治疗后,肿瘤组织CD4~ 、CD8~ 细胞浸润增加,结肠腺癌细胞表达H-2Kd和B7-1分子明显增加.提示经CD自杀基因和Ltn基因联合治疗后,肿瘤细胞免疫原性增加.本研究结果表明联合应用自杀基因和Ltn基因治疗可以提高机体对肿瘤细胞免疫的应答,增加机体的抗肿瘤作用,是肿瘤基因治疗中一条新的途径.     

IL-2基因与自杀基因联合转移对小鼠红白血病的治疗作用

用腺病毒作为载体,将大肠杆菌胞嘧啶脱氨酶(CD)基因体外转染小鼠红白血病FBL-3细胞,结果CD基因转移后该细胞对5-氟胞嘧啶(5-FC)的敏感性提高了近1000倍,FBL-3细胞有明显的凋亡发生,且观察到明显的旁观者效应.小鼠体内接种FBL-3红白血病细胞后3天,肿瘤局部注射小鼠白细胞介素2(IL-2)基因的表达载体(Ad-IL-2)和Ad-CD腺病毒载体,然后连续10天给予5-FC 300mg/kg行治疗.结果FBL-3皮下肿瘤的生长明显受到抑制,部分小鼠肿瘤消失.联合治疗小鼠的存活期明显大于单用Ad-IL-2治疗组和单用自杀基因CD与5-FC治疗组.体内免疫功能检测表明,经小鼠自杀基因与IL-2联合基因治疗后小鼠脾细胞的CTL杀伤     

腺病毒介导的CD/5FC自杀基因疗法对小鼠结肠腺癌的治疗作用及相关免疫机理的研究

大肠杆菌胞嘧啶脱氨酶CD可以将前体药物5FC代谢为毒性产物5FU,具有抗肿瘤作用.本课题我们观察了腺病毒介导的CD/5FC自杀基因疗法对小鼠结肠癌生长的治疗作用并探讨其作用机理.结果表明,首先,CD/5FC自杀基因疗法小鼠结肠癌CT26体内外生长均具有显著的抑制作用,4O%的荷瘤小鼠经过治疗后长期存活;其次,我们还研究了自杀基因疗法治疗肿瘤时可能涉及的免疫机理.结果发现在以CD/5FC系统治疗结肠腺癌小鼠过程中能在一定程度上诱导出机体的抗肿瘤免疫反应,包括脾脏CT6L活性的增高、肿瘤局部浸润免疫细胞表达,DEC-205、B7-2、I-A~(b,d)分子增加等.本实验结果提示虽然CD/5FC系统可以诱导机体产生一定的抗肿瘤免疫反应,但其程度不够显著.     

Enhanced antitumoral effect of adenovirus-mediated cytosine deaminase gene therapy by induction of antigen-presenting cells through stem cell factor/granulocyte-macrophage colony-stimulating factor gene transfer

Suicide gene therapy has been studied intensively for the treatment of cancer. A limited antitumoral effect was obtained by intratumoral injection of adenovirus harboring Escherichia coli cytosine deaminase gene (AdCD) in tumor-bearing mice followed by continuous administration of 5-fluorocytosine (5FC). To address the drawbacks of the limited potential for the induction of antitumoral immunity by CD suicide gene therapy, we hypothesized that antigen-presenting cells (APCs) might contribute to the efficient induction of an antitumoral immune response in tumor-bearing mice undergoing suicide gene therapy. We preinjected the mice with murine stem cell factor (SCF)-encoding adenovirus (AdSCF) and murine granulocyte-macrophage colony-stimulating factor (GM-CSF)-encoding adenovirus (AdGM-CSF); after 7 days, the mice were inoculated with CT26 colon adenocarcinoma. AdCD was injected intratumorally into tumor-bearing mice followed by 5FC administration. The results showed that AdSCF/AdGM-CSF treatment could increase the number, surface molecule expression, and function of APCs efficiently. A more significant growth inhibition of established tumors and a prolongation of the survival period were observed in tumor-bearing mice after AdSCF/AdGM-CSF pretreatment in combination with AdCD/5FC therapy when compared with mice treated with AdSCF or AdGM-CSF in combination with AdCD/5FC, or AdCD/5FC alone (P < .01). Cytotoxic T-lymphocyte activity was induced efficiently after the combined therapy, and mRNA of tumor necrosis factor-alpha, interleukin-4, interferon-gamma, and interleukin-2 was present in the tumor mass after combined therapy, suggesting that a more potent antitumoral response was induced by enhanced APCs. Our results demonstrated that AdSCF/AdGM-CSF pretreatment could activate APCs, and that these APCs could present the tumor antigens released from AdCD/5FC-killed tumor cells and activate the antitumoral response of the host, thus increasing the therapeutic efficiency of suicide gene therapy.     

肺腺癌组织特异性自杀基因治疗实验研究

目的 探讨肺腺癌组织特异性自杀基因治疗的安全性及有效性。方法 采用病毒感染法，将癌胚抗原(CEA)基因启动子所驱动的CD基因的组织特异性逆转录病毒载体(G1CEACDNa)，导入分泌CEA的肺腺癌细胞系A549细胞．研究裸鼠体内抑瘤效果；应用重组逆转录病毒裸鼠体内治疗A549肿瘤，观察G1CEACDNa／5-氟胞嘧啶(5-FC)对A549细胞致瘤裸鼠的治疗作用及毒副反应。结果 (1)将转基因的A549细胞和未转基因的A549细胞接种至裸鼠皮下．两者成瘤性无明显差异；(2)在转基因细胞致瘤裸鼠实验中，5-FC对转CEA启动子调控自杀基因的肿瘤生长具有明显的抑制作用；(3)将G1CEACDNa重组逆转录病毒上清直接注射到裸鼠成瘤部位．然后腹腔内注射5-FC同样获得明显的抑瘤效果；(4)与直接注射5-FU相比，组织特异性自杀基因治疗对骨髓的抑制明显降低。结论 组织特异性自杀基因治疗可能成为肿瘤治疗个体化的重要方法之一。     

Dose of Adenoviral Vectors Expressing Interleukin-2 Plays an Important Role in Combined Gene Therapy with Cytosine Deaminase/5–Fluorocytosine: Preclinical Consideration

Using a syngeneic murine model, we investigated the therapeutic efficacy of combined gene therapy using adenoviral vectors expressing murine interleukin-2 (AdmIL-2) and Escherichia coli cytosine deaminase (AdCD). In a subcutaneous tumor model, tumor-bearing mice were treated with an intratumoral injection of adenoviral vectors and received an intraperitoneal administration of 5–fluorocytosine (5–FC). Only the mice treated with AdCD (2×10⁸ pfu) and an intermediate dose of AdmIL-2 (1×10⁶ pfu) survived significantly longer than mice treated with AdCD alone ( P <0.01). Moreover, 40% of these treated mice obtained complete remission from tumor-bearing status. The cytotoxicity of splenocytes obtained from the treated mice was related to the survival period. Tumor-specific cytotoxic T lymphocyte assay showed that the cell-mediated cytotoxic response was specific for parental tumor cells. In a hepatic metastasis model, mice treated with an intravenous administration of both AdCD (2×l0⁸ pfu) and an intermediate dose of AdmIL-2 (1×10⁶ pfu) demonstrated the most significant reduction of metastatic foci and the longest survival following a 5–FC administration. These results suggest that gene therapy combined with AdmIL-2 and AdCD may be a promising strategy for clinical application and, in addition, that translation of combined gene therapy from murine models into the clinical setting will require careful attention to the variables of cytokine expression levels in the design of clinical trials and in the evaluation of treatment efficacy.     

Hypoxia imaging predicts success of hypoxia-induced cytosine deaminase/5-fluorocytosine gene therapy in a murine lung tumor model

Tc-99m-HL91 is a hypoxia imaging biomarker. The aim of this study was to investigate the value of Tc-99m-HL91 imaging for hypoxia-induced cytosine deaminase (CD)/5-fluorocytosine (5-FC) gene therapy in a murine lung tumor model. C57BL/6 mice were implanted with Lewis lung carcinoma cells transduced with the hypoxia-inducible promoter-driven CD gene (LL2/CD) or luciferase gene (LL2/Luc) serving as the control. When tumor volumes reached 100?mm(3), pretreatment images were acquired after injection of Tc-99m-HL91. The mice were divided into low and high hypoxic groups based on the tumor-to-non-tumor ratio of Tc-99m-HL91. They were injected daily with 5-FC (500?mg?kg(-1)) or the vehicle for 1 week. When tumor volumes reached 1000?mm(3), autoradiography and histological examinations were performed. Treatment with 5-FC delayed tumor growth and enhanced the survival of mice bearing high hypoxic LL2/CD tumors. The therapeutic effect of hypoxia-induced CD/5-FC gene therapy was more pronounced in high hypoxic tumors than in low hypoxic tumors. This study provides the first evidence that Tc-99m-HL91 can serve as an imaging biomarker for predicting the treatment responses of hypoxia-regulated CD/5-FC gene therapy in animal tumor models. Our results suggest that hypoxia imaging using Tc-99m-HL91 has the predictive value for the success of hypoxia-directed treatment regimens.     

Transduction of cytosine deaminase gene makes rat glioma cells highly sensitive to 5-fluorocytosine

To investigate the potential use of E. coli cytosine deaminase (CD) gene instead of the commonly used HSV-TK gene in the gene therapy of brain tumors, we constructed a retrovirus vector carrying the CD gene. We then transduced a rat glioma cell line C6 with CD gene by the retrovirus vector. Transduction of the CD gene made C6 cells become highly sensitive to the anti-fungi drug 5-fluorocytosine (5FC). IC₅₀ for 5FC was 6,000 μM in CD-negative cells, while it was 3 μM in Cd -positive cells. Mixed cellular assay showed that CD-positive cells had a strong “bystander effect” on CD-negative cells when exposed to 5FC. Significant anti-tumor effects were observed in nude mice bearing s.c. tumors derived from CD-positive cells when these animals were given 250 mg/kg 5FC twice a day for 20 consecutive days. A marked decrease in tumor weight occurred when a mixture containing 50% CD-positive and 50% CD-negative C6 cells was injected s.c., followed by 5FC treatment, suggesting the bystander effect in vivo. Concerning the pharmacokinetics of 5FC, especially its high oral bio-availability and good penetration into cerebrospinal fluid, we suppose that the combination of CD-gene transfer and 5FC oral administration may have potential use in the gene therapy of brain tumors. Int. J. Cancer 71:675-679, 1997. © 1997 Wiley-Liss, Inc.     

HA 纳米载体转 hGM - CSF 基因的 HepG2 疫苗联合多柔比星抗肝癌作用

目的：评价HA纳米载体转hGM—CSF基因的HepG2疫苗联合多柔比星治疗肝癌的效果。方法：建立Hu—PBL—SCIDHepG2荷瘤小鼠模型,待皮下种植瘤长至100—150mm3时,随机分为5组,每组5只：对照组（PBS）;化疗组（多柔比星DOX）;疫苗组（60Co照射的转染GM—CSF基因的HepG2细胞）;先疫苗后化疗组;先化疗后疫苗组。末次治疗后第5天处死各组小鼠,用MTT法测定脾脏CTL活性及肿瘤组织浸润淋巴细胞（TIL）杀伤活性;取肿瘤组织行HE染色及CD8＋T细胞免疫组化检查。结果：化疗组的CTL活性与对照组相比无显著变化（P〉0．05）。疫苗组和先疫苗后化疗组及先化疗后疫苗组的CTL活性显著强于上述两组（P〈0．05）,该3组两两之间也存在显著差异（P〈0．05）,而先化疗后疫苗组的CTL活性增强最为明显,明显高于其他两组（P〈0．05）。该组的TIL活性同样强于其他各组。同其它组相比,先化疗后疫苗组的瘤体内可见大量肿瘤细胞坏死,CD8＋T细胞浸润显著增加。结论：HA纳米载体转染hGM—CSF基因的HepG2疫苗的主动免疫联合多柔比星化疗具有协同抗肝癌作用,为肿瘤免疫联合化疗治疗肿瘤提供了实验依据。     

hTERT启动子调控的CD：UPRT／5-FC自杀基因对人胃癌裸鼠移植瘤的抑制作用

目的：研究人端粒酶逆转录酶（hTERT）启动子调控的胞嘧啶脱氨酶：尿嘧啶磷酸核糖转移酶／5-氟胞嘧啶（CD：UPRT／5-FC）融合自杀基因系统在体内对人胃癌SGC7901细胞的杀伤作用。方法：构建胃癌皮下移植瘤模型,随机分成3组处理。观察30天,测量肿瘤体积,计算抑瘤率。肿瘤组织做常规病理检查,免疫组化检测CD蛋白的表达。结果：成功构建胃癌皮下移植瘤模型。治疗30天后,B组（瘤内注射hTERT—CD：UPRT＋腹腔注射PBS）和c组（单纯腹腔注射PBS）的肿瘤生长迅速,肿瘤体积分别为（2．72±0．35）cm’、（2．67-＇i-0．30）tin’,A组（瘤内注射hTERT—CD：UPRT＋腹腔注射5-Fc）的肿瘤生长受到明显抑制,第30天体积为（1．10±0．13）cm’,与前两组相比差异有统计学意义（P〈0．05）,其抑瘤率为59．6％。裸鼠移植瘤病理切片镜检,A组可见大量肿瘤细胞排列稀疏,部分肿瘤细胞核固缩、核碎裂;B组和C组则见大量肿瘤细胞排列紧密,细胞形态和细胞核呈多形性,核大深染,核分裂像多见。免疫组化显示,A组和B组可见CD的表达,C组cD表达呈阴性。结论：hTERT启动子调控的cD：UPRT／5-FC融合自杀基因系统对裸鼠胃癌皮下移植瘤有显著的杀伤作用,为胃癌的基因治疗提供了-种可能的方法。