大肠癌的自杀基因治疗实验研究进展

自杀基因治疗恶性肿瘤是目前肿瘤基因治疗中的热点 ,但在治疗大肠癌方面却起步较晚。本文综述近几年自杀基因治疗大肠癌的实验研究进展。     

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。     

卵巢癌的自杀基因治疗

卵巢癌自杀基因治疗多采用HSVtkGCV系统和CD5FC系统。通过自杀基因的表达产物将无毒性的药物转化为有毒性的药物及旁观者效应杀死肿瘤细胞。尽管目前还存在转染效率、靶向性等问题有待改进，但随着自杀基因的不断完善，联合基因、联合细胞因子治疗及联合放疗等策略的采用，自杀基因在卵巢癌治疗上将具有广阔的应用前景。     

肝癌自杀基因治疗的新进展

肝癌自杀基因治疗的新进展覃汉荣杨冬华肝癌是世界上最常见的恶性肿瘤之一，病死率高，预后凶险。尽管手术、化疗、放疗等常规疗法和其它治疗手段，使肝癌的预后得到相当程度的改善，然而对晚期肝癌仍缺乏有效的治疗手段，每年全世界死于肝癌的病人估计达到１２５万［１］...     

自杀基因治疗恶性胶质瘤的研究

目的：单纯疱疹病毒Ⅰ型胸苷激酶（ＨＳＶ－ｔｋ）基因治疗恶性胶质瘤体内外试验。方法：分子克隆及真核细胞基因转染技术构建逆转录病毒（ＲＶ）载体ｐＭＶ７（ｔｋ）及ＰＡ３１７ｔｋ包装细胞系;体外不同比例混合鼠Ｃ６胶质瘤细胞与ＰＡ３１７ｔｋ细胞,在ＧＣＶ（Ｇａｎｃｉｃｌｏｖｉｒ）作用下观察细胞存活率;建立ＳＤ大鼠颅内Ｃ６胶质瘤模型（种植５×１０５Ｃ６细胞）,治疗组第３天原位注射５×１０６ＰＡ３１７ｔｋ细胞,５天后腹腔给予ＧＣＶ（３０ｍｇ／ｋｇ．ｄ）,ＭＲＩ全程监测肿瘤消长,观察病症及存活期,并行病理检查。结果：在ＧＣＶ０．１～１０１μｇ／ｍｌ浓度范围内,Ｃ６细胞存活率随ＰＡ３１７ｔｋ细胞混入比例增加而逐渐减低（Ｐ＜０．００１）,并具有ＧＣＶ剂量依赖性（Ｐ＜０．０１）;体内试验治疗组病症轻,生存期延长,ＭＲＩ表明治疗组肿瘤体积较对照组明显减小（Ｐ＜０．０１）,１个月时病理检查见肿瘤细胞消失,代之以小胶质细胞增生并形成坏死囊。结论：应用本实验室构建的ＲＶ载体ｐＭＶ７（ｔｋ）及其ＰＡ３１７ｔｋ包装细胞系治疗恶性胶质瘤是一种有效及具有前途的治疗方法。     

自杀基因治疗肿瘤研究现状与展望

本文综合论述了自杀基因的国内外研究现状，较详细描述了自杀基因治疗肿瘤的机理及转导方法，并对自杀基因的进一步研究方向进行展望。     

自杀基因治疗恶性肿瘤研究进展

恶性肿瘤的基因治疗是现代医学领域的研究热点，其中自杀基因疗法可能成为一种极具潜力和临床应用价值的治疗手段，在治疗范围上，已扩大到全身所有脏器及各种组织类型的恶性肿瘤，在提高其转录靶向调控机制上，已发现了许多特异性启动子元件，来增强自杀基因作用的特异性及可调控性，并已尝试利用辐射诱导来提高其转基因表达的外源性调控机制；此外，采用自杀基因与集落刺激因子(GM—CSF)、细胞因子等联合应用，诱导产生更强的抗肿瘤免疫，进一步增强杀伤肿瘤的效力。     

自杀基因治疗恶性肿瘤的研究现状及展望

肿瘤的自杀基因疗法是近年来肿瘤基因治疗的研究热点,是一种具有潜在临床应用前景的新的肿瘤基因治疗策略.本文就近年来自杀基因疗法在肿瘤治疗中取得的研究进展,分别从作用机制、自杀基因系统、旁观者效应、自杀基因的转导以及联合基因治疗等几个方面进行综述.     

自杀基因治疗恶性肿瘤的研究现状及展望

肿瘤的自杀基因疗法是近年来肿瘤基因治疗的研究热点,是一种具有潜在临床应用前景的新的肿瘤基因治疗策略。本文就近年来自杀基因疗法在肿瘤治疗中取得的研究进展,分别从作用机制、自杀基因系统、旁观者效应、自杀基因的转导以及联合基因治疗等几个方面进行综述。     

乳腺癌的自杀基因治疗研究进展

从自杀基因治疗乳腺癌的研究现状、自杀基因体系、旁观者效应、临床试验研究等方面综述了近几年自杀基因治疗乳腺癌的实验和临床研究的进展     

Suicide Gene Therapy for Chemically Induced Rat Bladder Tumor Entailing Instillation of Adenoviral Vectors

The efficacy of an in vivo gene therapy protocol making use of an adenoviral vector in the treatment of bladder cancer was examined. Bladder tumors were induced in rats by oral administration of BBN (N-butyl-N-(4-hydroxybutyl)nitrosamine). Histologically, such tumors resemble those seen in human bladder cancer, and the cells can be selectively transduced using adenoviral vectors. The therapeutic protocol thus entailed instillation of an adenoviral vector containing the HSV-tk suicide gene into rat bladder followed by a regimen of intraperitoneal ganciclovir (GCV) injections. Histological examination after a short-term GCV regimen (3 days) revealed marked vacuolization of the tumor cells. Moreover, TUNEL assays showed that the cytotoxic reaction was mediated by apopto-sis. Following a long-term GCV regimen (14 days), tumor growth was significantly inhibited and glandular metaplasia was observed. This is the first report demonstrating the efficacy of in vivo suicide gene therapy in a chemically induced transitional cell carcinoma like that seen in most human bladder cancer. Intravesical instillation is already a well established clinical technique. Our findings indicate that now there is a strong potential for its incorporation into new and useful gene therapies aimed at the treatment of human bladder cancer.     

Sequential Histopathological Changes in vivo after Suicide Gene Therapy of Gastric Cancer Induced by N-Methyl-N'-nitro-N-nitrosoguanidine in Rats

Gastrointestinal cancer is the most important clinical target of gene therapy. Suicide gene therapy, such as with the herpes simplex virus type 1 thymidine kinase ( HSV-TK ) gene, has been shown to exert antitumor efficacy in various cancer models in vitro. We previously reported in situ gene transfer and gene therapy for gastric cancer induced by N -ethyl-. N '-nitro-. N -nitrosoguanidine (ENNG) in dogs. Here, we describe the sequential histopathological changes after suicide gene therapy of N -methyl-. N '-nitro-. N nitrosoguanidine (MNNG)-induced gastric cancer in rats. Gastric tumors were induced by MNNG in 38/73 (52%) of Wistar strain rats. The suicide gene therapy group (14 rats) was subjected to in situ gene transfer with a recombinant adenovirus vector carrying the HSV-TK gene driven by CAG promoter (Ad.CAGHSV-TK) in gastric tumor, followed by the antiviral drug ganciclovir (GCV). To observe the histopathological changes at various tunes after HSV-TK/GCV gene therapy, groups of animals were sacrificed at 3, 8, and 30 days after gene transfer. Apoptosis in the gastric tumors was detected by the TUNEL method to assess the efficacy of HSV-TK/GCV gene therapy, and it was marked in the 8- and 30-day treatment groups compared to the sham operation controls ( P <0.001). Various histopathological changes, degeneration of cancer tissue and fibrosis after necrosis and apoptosis were significantly greater in the 30-day treatment group. The HSV-TK gene was detectable in peripheral blood by PCR until 30 days after gene transfer. These results may be useful in devising a method of suicide gene therapy for humans.     

自杀基因在肺癌中的研究进展

全文从自杀基因治疗体系的构成、作用机制、旁观者效应、与其他治疗联合应用、提高自杀基因转导效率及其在肺癌中的研究进展进行综述.     

5-FC/CD 自杀基因疗法结合热休克蛋白-多肽复合物瘤苗治疗小鼠黑色素瘤的研究

 目的　研究 5 -氟尿嘧啶 /胞嘧啶脱氨酶 (5 FC/ CD)基因疗法与热休克蛋白 -多肽复合物 (HSP- PC)瘤苗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黑色素瘤体内 ,腹腔注射 5 - FC,同时皮下接种 HSP70 - PC。结果　经联合治疗后 ,70 %荷瘤小鼠肿瘤体积缩小、消退 ,小鼠存活期延长 ,肿瘤组织明显坏死 ,炎症细胞、CD+4 及 CD+8T细胞浸润明显。结论5 - FC/ CD基因疗法结合 HSP- PC瘤苗免疫疗法抗小鼠黑色素瘤作用显著 ,具有临床应用前景。     

膀胱移行上皮癌中P16蛋白的表达意义

采用免疫组织化学LSAB法对68例膀胱移行上皮癌标本中的抑癌基因p16表达产物进行检测，29例显示表达阳性，且阳性表达率在恶性度低、浅表性和未复发膀胱肿瘤中较高，Ⅰ级与Ⅱ级、Ⅰ级与Ⅲ级、Tis～T1与T2～T4、及复发与未复发比较均有显著性差异（P＜0．05）。表明p16蛋白表达与膀胱移行上皮癌的分化程度、浸润深度及预后有关。     

重组pcDNA3-UpIb promoter-Smac质粒转染靶向膀胱癌的促凋亡效应

目的：探讨转染新构建的UpIb启动子调控携Smac基因的真核表达质粒pcDNA3-UpIb promoter—Smac对膀胱癌细胞的促凋亡效用一方法：用脂质体将质粒转染到膀胱癌BIU-87细胞系中，2dh后用RT—PCR检测Smac的表达，以低剂量丝裂霉素C诱导凋亡，利用倒置光学显微镜、Wrighs—Gimesa染色、DNA凝胶电泳技术、TUNEL-荧光标记技术、流式细胞术检测凋亡。结果：丝裂霉素C处理的各组在倒置光学显微镜和Wrighs—Gimesa染色油镜下可见到典型的凋亡形态学改变，DNA凝胶电泳呈特征性的梯形条带jTUNEL-荧光标记技术及流式细胞术检测转染pcDNA3-UpIb promoter—Smac组凋亡率显著高于单用丝裂霉素C组。结论：转染pcDNA3-Up Ibpromoter—Smac能够通过提高Smac的表达而有效促进丝裂霉素C诱导的膀胱癌细胞凋亡，提示该质粒配合凋亡诱导药物可能成为膀胱癌新的靶向基因治疗手段．     

p16基因在膀胱肿瘤细胞凋亡中的作用

 目的　探讨p16基因与膀胱肿瘤细胞凋亡的关系。方法　应用SABC免疫组织化学法检测了51例膀胱移行细胞癌p16基因的表达,同时用流式细胞仪检测其细胞凋亡情况。结果　p16阳性表达率为47.1%(24/51),平均凋亡肿瘤细胞百分比为1.5%,p16阳性表达的肿瘤组织凋亡细胞百分比>1.5%的发生率为62.5%,p16阴性表达的肿瘤组织凋亡细胞百分比>1.5%的发生率为25.9%,两者比较有显著性差异(P<0.01)。结论　p16基因的表达与膀胱肿瘤细胞凋亡有关,p16基因可能参与膀胱肿瘤细胞凋亡的正向调节作用。     

In situ Gene Transfer and Suicide Gene Therapy of Gastric Cancer Induced by N-Ethyl-N'-nitro-N-nitrosoguanidine in Dogs

Gene therapy could potentially revolutionize the treatment of gastrointestinal (GI) tract cancer. The aim of this study was to establish a practical method of gene transfer which would be applicable to human gastric cancer. Retrovirus or/and adenovirus vectors carrying the lacZ marker gene were transferred in situ by needle through an endoscopic biopsy channel into primary gastric cancer in six male beagle dogs that had been treated with N-ethyl-N'-nitro-N-nitrosoguanidine (ENNG). In addition, an adenovirus vector carrying the herpes simplex virus thymidine kinase (Ad.CAGHSV-TK) gene was introduced in situ into cancer tissues in the stomach of three dog, and the animals were treated with intravenous ganciclovir (GCV). Retrovirus-producing cells which expressed the lacZ gene were specifically localized to the injection site in the stomach. The lacZ gene was more widely transferred into the tumor by the adenovirus vector than by retrovirus-producing cells. Improvement of the needle used for gene transfer and the use of multiple injections per tumor led to more diffuse transfer of the vector into the tumor. The Ad.CAG lacZ gene was also transferred into regional lymph nodes of the stomach. Moderate to diffuse degeneration of the primary cancer tissues of the stomach was found after Ad.CAGHSV-TK/GCV gene therapy. Moreover, almost complete tissue degeneration was observed in the regional lymph nodes of the stomach. An adverse effect of HSV-TK/GCV gene therapy was acute hepatotoxicity, which was not found after Ad.CAG lacZ gene transfer, but was found after high-titer Ad.CAGHSV-TK gene transfer followed by GCV. These findings suggest that in situ gene transfer of a suicide gene followed by prodrug treatment may be applicable not only to primary tumors, but also to lymph node metastases of gastric cancer, though further study of both beneficial and adverse effects is required before clinical usage.