骨肉瘤基因治疗研究进展

骨肉瘤是一种临床常见恶性骨肿瘤。尽管骨肉瘤的治疗有了长足的进展，近80％患者能保留病肢，且5年生存率由20％左右提高到近80％，但仍有半数以上的患者死于骨肉瘤的转移和复发。随着肿瘤分子生物学的发展，肿瘤基因治疗概念的提出及实验研究结果，显示出其良好的临床应用潜力。到目前，人们针对骨肉瘤及其肺转移已探索开展了抑癌基因治疗、反义基因治疗、自杀基因、免疫基因治疗、药物抵抗基因治疗、联合基因治疗和肿瘤特异性靶向治疗研究等多种极富前景的肿瘤基因治疗方法，现综述如下。     

肿瘤基因治疗技术

肿瘤基因治疗就是将一段特定的遗传信息物质DNA或RNA通过人工方法导入肿瘤细胞以治疗肿瘤性疾病,目前的研究主要包括三个方面;肿瘤免疫基因治疗,反义RNA、三链DNA。其中研究较多的是肿瘤免疫基因治疗。本文主要对肿瘤免疫基因治疗的构建、接种,应用等方面做了综述。并简要介绍了反义RNA和三链DNA技术。     

前列腺癌的基因治疗研究进展

前列腺癌是西方国家常见肿瘤，在我国的发病率也逐年上升。对于晚期。复发性或激素非依赖的患者，目前缺乏有效的治疗手段。前列腺癌的基因治疗是近年来国内外学者研究的热点，作为一种全新的治疗方法。其临床前实验研究已显示出令人鼓舞的前景，本文综述前列腺癌基因治疗的主要策略及其研究进展。     

恶性肿瘤基因治疗研究进展

恶性肿瘤的基因治疗仍是目前进展很快的研究领域.用于基因治疗的候选基因很多,本文主要综述自杀基因、肿瘤抑制基因和耐药基因等几种基因治疗方法的进展及其在恶性肿瘤治疗中的应用.     

基因导向性酶前体药物疗法在肿瘤治疗中的研究进展

基因导向性酶前体药物疗法(GDEPT)为肿瘤生物治疗最引人注目的研究领域,是继手术、放疗和化疗等传统疗法之后,一种具有良好应用前景的肿瘤治疗新措施,主要包括HSV-tk-GCV系统疗法和CD-5-FC系统疗法.为克服传统GDEPT疗法的不足,目前多主张联合基因治疗肿瘤,有人还提出一种全新的GDEPT疗法.现综述近几年来GDEPT在肿瘤基因治疗中的研究进展.     

肿瘤自杀基因靶向治疗的研究进展

自杀基因治疗是目前肿瘤基因治疗中的研究热点.本文重点从自杀基因的种类、载体、作用机制和发展应用前景等几方面进行综述.其中HSV1-tk/GCV自杀基因系统是研究最多、临床价值最为明确的自杀基因系统之一.治疗机制上除通过直接作用和旁观者效应发挥作用外,还从自杀基因联合使用、趋化因子等细胞因子作用、自杀基因与放射治疗联合作用、自杀基因与免疫治疗联合使用等多方面进行了探索和研究.众多研究结果认为自杀基因治疗是一种具有良好应用前景的肿瘤治疗方法,但在临床应用上还有很多问题需要解决,如将自杀基因安全、高效地转染到人体肿瘤组织和细胞中的方法,如何能使自杀基因在靶组织中稳定表达并发挥作用,各种治疗方法的协同作用等,均有待于我们在今后的研究中进一步解决.     

基因治疗联合放射治疗恶性肿瘤

肿瘤基因治疗就是应用基因工程的方法校正和修复与肿瘤发生有关的变异基因，或通过改变某些细胞的生物学特性增强宿主的抗瘤能力，从而达到治疗肿瘤目的的一类疗法。近年来，随着肿瘤病因学研究的不断深入和生物医学技术的飞速发展，肿瘤基因治疗已成为肿瘤治疗研究的热点之一。虽然目前该疗法中的某些方案已进入临床试验阶段，但由于肿瘤的发生涉及很多基因的改变，很难想象只针对个别基因进行基因治疗就能彻底治愈肿瘤；另外，目前基因转移系统的效率尚难以使每一个肿瘤细胞都受到基因治疗的作用。     

基因导向性酶前体药物疗法在肿瘤治疗中的研究进展

基因导向性酶前体药物疗法(GDEPT)为肿瘤生物治疗最引人注目的研究领域，是继手术、放疗和化疗等传统疗法之后，一种具有良好应用前景的肿瘤治疗新措施，主要包括HSV-tk-GCV系统疗法和CI)-5-FC系统疗法。为克服传统GDEPT疗法的不足，目前多主张联合基因治疗肿瘤，有人还提出一种全新的GDEPT疗法。现综述近几年来GDEPT在肿瘤基因治疗中的研究进展。     

胶质瘤联合基因治疗研究进展

 胶质瘤是颅内常见肿瘤,预后不佳。肿瘤的基因治疗是目前研究热点之一,主要策略有:自杀基因治疗、控制细胞周期及诱导凋亡、免疫基因治疗、抗血管生成基因治疗以及应用溶瘤病毒等[1] 。但单一途径的治疗效果并不理想,胶质瘤的联合基因治疗研究近年发展较快,本文就此作一综述。     

胃肠道肿瘤的基因治疗研究进展

肿瘤基因治疗是一种具有潜在应用价值的新的肿瘤治疗手段。本文就其在胃肠道肿瘤中的研究进展进行了综述。内容包括细胞因子基因治疗、反义基因治疗、自杀基因治疗及抑癌基因治疗等，这些基因治疗在体内外显示了良好的治疗胃肠道肿瘤的效果。本文也介绍了这几种治疗方法抑制和杀死肿瘤细胞的机理，为胃肠道肿瘤基因治疗的深入研究提供了一定的依据。     

Adenovirus-mediated p16INK4 gene transfer significantly suppresses human breast cancer growth

The p16INK4 tumor suppressor gene encodes a protein that inhibits cyclin-dependent kinase 4, and its homologous deletion is common in human breast cancer. p16INK4 gene transfer has been reported to be efficacious in inducing growth inhibition of various human tumors such as brain, lung, prostate, and esophageal cancers. However, the efficiency of the p16INK4 gene with regard to growth inhibition of human breast cancer has not been studied extensively. To examine its tumor-suppressive function and its potential in breast cancer gene therapy, the wild-type p16INK4 gene was expressed in an adenovirus-mediated gene delivery system and introduced into breast cancer cell lines that do not express p16INK4 protein. Expression of the introduced p16INK4 blocked tumor cell entry into the S phase of the cell cycle, induced tumor cell apoptosis, and inhibited tumor cell proliferation both in vitro and in vivo. These results strongly suggest that p16INK4 is a tumor suppressor gene and suggest that it has potential utility in breast cancer gene therapy.     

Radiation-guided gene therapy of cancer

Gene therapy has been proposed as a means to combat cancer. However, systemic toxicity observed in preclinical trials suggested the importance of selectively targeted delivery and inducible gene expression in tumor tissues. Discovery of radiation-inducible promoter sequences provides one way to minimize inadvertent toxicity from gene therapy in normal tissues. Radiation is administered to selectively induce cytotoxic gene expression in the targeted tumor tissues. With promising results from phase II clinical trials using TNF-expressing adenovirus, it is possible to have radiation-guided gene therapy regimes once the tumor-targeted delivery has been achieved. Tumor endothelium is an attractive biological target for gene therapy, because it has the advantage of stability, accessibility, and bioavailability for therapeutic agents. Technological development of DNA microarray, proteomic profiling, and phage-displayed libraries accelerates the identification of tumor-specific endothelial biomarkers and discovery of its relevant affinity reagents for targeted delivery. The application of radiation-guided gene delivery, its amplification, as well as expression of gene therapy presents great opportunities to be employed as an alternative cancer treatment.     

Tissue specific expression of suicide genes delivered by nanoparticles inhibits gastric carcinoma growth

Developing an efficient and safe strategy to introduce a therapeutic gene into targeting cells in vivo is a key issue in cancer gene therapy nowadays. Novel non-viral gene carriers, such as nanoparticles, have been shown to be able to deliver DNA into cancer cells efficiently. Suicide gene therapy has been demonstrated to be effective in inhibiting tumor growth, however, the lack of tumor specificity limits its application in clinic. Developing a targeting system for suicide gene is an attractive strategy in cancer gene therapy. In this study, the CMV enhancer and carcinoembryonic antigen (CEA) promoter was fused to a chimeric suicide gene yCDglyTK. This construct was delivered into SGC7901 gastric cancer cells using calcium phosphate nanoparticles (CPNPs). The expression of yCDglyTK in SGC7901 cells was confirmed by RT-PCR and western blot. Immunofluorescence experiments showed that yCDglyTK is only expressed in CEA-positive cancer cells, but not in CEA-negative cells. The expression of yCDglyTK induced cancer cell death following the addition of the prodrug 5-FC, and also elicit "bystander effect" to kill the neighboring cells. Intratumoral injection of CPNP-yCDglyTK complex followed by administration of 5-FC produced marked regression in gastric cancer xenografts. Taken together, our study suggests that the combination of calcium phosphate nanoparticles and suicide gene therapy represents a novel approach for targeting gastric cancer gene therapy.     

癌症靶向治疗的新趋势

靶向性是癌症治疗的关键所在，新的治疗方案必须在特异性作用于肿瘤的同时降低对正常细胞的损伤，目前已取得了许多成果：1）肿瘤的靶向基因一病毒治疗结合了基因治疗和病毒治疗的各自优势。所用的病毒载体具有特异性靶向肿瘤的作用并在肿瘤细胞中大量复制和高效表达抗癌基因，如果用2个特异性启动子严格控制病毒只在肿瘤中表达，并加上2个有协同效应的抗癌基因即可达到极好的抗癌效果。2）在抗体治疗方面，运用第1代腺病毒高效表达Herceptin或是Rituxan抗体基因已取得成功，它可以大大地降低目前昂贵的抗体治疗费用。3）RNA干扰技术可以沉默致病基因，选用质粒或是病毒做载体可以达到长期及高效的基因沉默效果。4）具有自我更新能力的肿瘤干细胞是肿瘤复发的关键。5）人们也逐渐意识到肿瘤的形成过程是癌细胞与基质细胞相互作用的结果，以肿瘤基质为靶标的药物也显示出了良好的效果。6）针对蛋白酪氨酸激酶或是抗凋亡蛋白而研制的小分子靶向药物也在肿瘤分子治疗上取得了成功。7）纳米技术正以其独特性而引起广泛关注。总之，在众多新型治疗方案研发的同时，我们必须认识到仅仅靠一种方法是难以成功根治肿瘤的，各种靶向治疗方案之间的相互结合将成为肿瘤治疗的主攻方向。     

Strategies for Prostate Cancer Gene Therapy

Gene therapy for prostate cancer is a relatively new experimental treatment modality and several different therapeutic approaches are being considered. Prostate cancer is the most commonly diagnosed cancer in males and has unique features that make it ideal for gene therapy. Although prostate cancer that is confined to the gland can be cured in many of the patients using local treatments (radical prostatectomy or irradiation therapy), the long-term failure rate of these therapies suggests that cancers can metastasize relatively early in the course of the disease. Once prostate cancer has metastasized there are no curative therapies. The greatest challenge in the treatment of advanced prostate cancer is to access and eliminate metastatic cells. Therefore, successful prostate cancer gene therapy will ultimately require an effective strategy to kill cancer cells both at the site of the primary tumor and at distant metastatic sites. In this article we review many aspects of gene therapy specifically relevant for prostate cancer. We discuss the unique advantages and disadvantages of nonviral and viral gene delivery systems. Evidence that gene delivery directly into tumors, in situ, is effective for prostate cancer is presented. We provide a broad review of three general approaches or strategies for prostate cancer gene therapy: corrective, cytoreductive, and immuno-modulatory gene therapy. Replacement of the tumor suppressor gene p53 is the best studied example of corrective gene therapy. The cytoreductive gene therapy that has been used most extensively is herpes simplex virus thymidine kinase (HSV-tk) combined with the prodrug ganciclovir. Immunomodulatory gene therapy approaches such as enhancement of cancer cell recognition, e.g. with antigen encoded gene vaccine approaches, and augmentation of the cellular immune response with specific immunomodulatory molecules such as interleukin-12 have the potential to effectively treat both local prostate cancer and distant metastases.     

癌症靶向治疗的新趋势

靶向性是癌症治疗的关键所在,新的治疗方案必须在特异性作用于肿瘤的同时降低对正常细胞的损伤,目前已取得了许多成果:1)肿瘤的靶向基因-病毒治疗结合了基因治疗和病毒治疗的各自优势。所用的病毒载体具有特异性靶向肿瘤的作用并在肿瘤细胞中大量复制和高效表达抗癌基因,如果用2个特异性启动子严格控制病毒只在肿瘤中表达,并加上2个有协同效应的抗癌基因即可达到极好的抗癌效果。2)在抗体治疗方面,运用第1代腺病毒高效表达Her-ceptin或是Rituxan抗体基因已取得成功,它可以大大地降低目前昂贵的抗体治疗费用。3)RNA干扰技术可以沉默致病基因,选用质粒或是病毒做载体可以达到长期及高效的基因沉默效果。4)具有自我更新能力的肿瘤干细胞是肿瘤复发的关键。5)人们也逐渐意识到肿瘤的形成过程是癌细胞与基质细胞相互作用的结果,以肿瘤基质为靶标的药物也显示出了良好的效果。6)针对蛋白酪氨酸激酶或是抗凋亡蛋白而研制的小分子靶向药物也在肿瘤分子治疗上取得了成功。7)纳米技术正以其独特性而引起广泛关注。总之,在众多新型治疗方案研发的同时,我们必须认识到仅仅靠一种方法是难以成功根治肿瘤的,各种靶向治疗方案之间的相互结合将成为肿瘤治疗的主攻方向。     

Use of H19 regulatory sequences for targeted gene therapy in cancer

We present a tumor gene therapy approach based on the use of regulatory sequences of the H19 gene that are differentially expressed between normal and cancer cells. We constructed expression vectors carrying the gene for the A fragment of diphtheria toxin (DT-A) or herpes simplex virus thymidine kinase (HSV-tk), under the control of a 814 bp 5'-flanking region of the H19 gene. The cell killing activity of these constructs was in accordance with the relative activity of the H19 regulatory sequences in the transfected cells. We evaluated the therapeutic potential of the gene expression constructs driven by H19 regulatory sequences in an animal model of bladder cancer induced by subcutaneous injection of syngeneic bladder tumor cell lines. Intratumoral injection of these constructs caused a significant suppression of subcutaneous tumor growth, with no obvious toxicity toward the host.     

基因-病毒治疗系统CNHK200-hA对肺癌治疗的研究

目的　构建抗肿瘤新生血管生成的基因治疗与病毒治疗相结合的基因 病毒治疗系统CNHK2 0 0 hA ,并对其肺癌的体内外治疗作用进行初步研究。方法　通过Westernblot分析 ,观察携带抗肿瘤新生血管生成基因angiostatink1 5 (hA)的基因 病毒治疗系统CNHK2 0 0 hA和非增殖型腺病毒对介导k1 5蛋白表达的影响 ;通过细胞病理作用及动物试验 ,比较CNHK2 0 0 hA和非增殖型腺病毒对人肺癌细胞株A5 4 9的杀伤作用及对肺癌裸鼠移植瘤的治疗作用。结果　基因 病毒治疗系统CNHK2 0 0 hA能够介导hA基因在肺癌细胞内高效表达k1 5蛋白 ,其表达量高于非增殖型腺病毒Ad hA。细胞病理效应显示 ,CNHK2 0 0 hA对A5 4 9的杀伤作用明显优于Ad hA ,CNHK2 0 0 hA在感染复数 (MOI)值为 1时可完全杀伤A5 4 9细胞 ,而达到相同杀伤效应的Ad hA的MOI值为 1 0 0。动物试验显示 ,CNHK2 0 0 hA对肺癌的疗效明显好于Ad hA及肿瘤增殖型病毒ONYX 0 1 5。结论　插入了抗肿瘤新生血管生成基因hA的基因 病毒治疗系统CNHK2 0 0 hA ,可明显提高hA基因的表达量 ,其在体内外的抗肺癌作用较非增殖型腺病毒Ad hA及肿瘤增殖型病毒ONYX 0 1 5进一步提高。     

Regional therapy with DTA-H19 vector suppresses growth of colon adenocarcinoma metastases in the rat liver

Curative surgery is possible in barely 10% of patients with colorectal liver metastases and combined treatment modalities scarcely improve survival in this group of patients. Hence, investigations of new therapeutic modalities are crucial. Overexpression of the H19 gene in liver metastases points to H19 as a target for cancer gene therapy. Here we have evaluated the possibility of regional intra-arterial treatment of liver meta-stases with the DTA-H19 plasmid. Intra-arterial treatment of a total dose of 2.5 mg (repeated injections of 500 μg DTA-H19 plasmid each dose after the first injection of 1000 μg) caused a significant delay in the tumor growth compared to control group. All of the tumors treated with the control vector increased in size, whereas 35.7% of the tumors in the groups treated with a total amount of 2.5 mg DTA-H19 plasmid shrank in size. The present study showed that the DTA-H19 plasmid administered intra-arterially significantly delayed the tumor growth and even resulted in tumor regression in high percentage of the treated animals with liver metastases of colon cancer. Since human liver metastases demonstrated overexpression of the H19 gene, regional administration of the plasmid seems to be a promising therapeutic approach.     

Familial thyroid cancer

Familial thyroid cancer can arise from parafollicular cells (familial medullary thyroid cancer) or from follicular cells (familial nonmedullary thyroid cancer). Familial medullary thyroid cancer may occur in isolation or as part of multiple endocrine neoplasia (MEN) type II syndromes. Genetic testing for a RET mutation on chromosome 10 is used to identify new family members who are gene carriers. Total thyroidectomy should be used in gene carriers without clinical disease before age 6 in medullary thyroid cancer and MEN type IIA, and as soon as the diagnosis is made in MEN type IIB after the first year of life. Those with clinical disease should have at least a bilateral central neck dissection. Modified radical neck dissection is recommended for patients when the primary tumor is 1.5 cm. A normal postoperative serum calcitonin level suggests that the operation has been curative. Physicians need to be aware of ethical and lifestyle issues related to patients with familial disease and their family members. Familial nonmedullary thyroid cancer occurs as a discrete entity or as part of other family cancer syndromes such as Gardner syndrome, Cowden disease, and other rare syndromes. Familial nonmedullary thyroid cancer almost exclusively includes patients with papillary or Hurthle cell cancers. These families appear to have more benign thyroid conditions. The gene (or genes) for familial papillary thyroid cancer is yet to be identified, whereas that for some Hurthle cells (TCO) has been mapped to chromosome 19p13.2. Familial nonmedullary thyroid cancer is somewhat more aggressive than its sporadic counterpart, but is less aggressive than medullary thyroid cancer. Total thyroidectomy and central neck dissection followed by radioactive iodine ablation and thyroid hormone suppression appear to be the most effective therapy.