Gene-Product Auto-Targeting to Tumor Vessels

肿瘤靶向基因递送技术的研究虽已取得了很大进展，但尚未引起足够的重视 靶向治疗性基因产物，所述治疗性基因产物是从转染的基因转录和翻译的， 正常组织转化为肿瘤肿瘤靶向基因产物是系统性基因治疗的重要内容 因为只有一部分基因被成功地递送到肿瘤中， 成功的系统性肿瘤靶向基因递送技术。在肿瘤中靶向基因产物也是 对于肿瘤内基因递送是重要的，因为最常用的治疗基因如TRAIL 产生分泌到血液循环中并对正常细胞有害的可溶性蛋白质。 此外，一些基因产物如IL-12在与肿瘤共定位时更有效， 与系统定位相比（Li，S.，JNCI，2002; Li，S.，Mol Therapy，2005）。在本申请中， 申请人将选择有效的肿瘤血管靶向肽来靶向或锚治疗基因 从注射的基因转录和翻译的产物进入肿瘤。尤其是肿瘤血管- 编码所选肿瘤血管锚定小肽的锚定IL-12基因和IL-12将被 产生并将通过电脉冲施用到肿瘤中以实现肿瘤靶向基因 递送和肿瘤靶向基因产物自动递送。假设IL-12的增加 通过使用肿瘤血管锚定的IL-12在肿瘤中积累和减少IL-12在血清中的循环 电基因疗法将大大降低全身毒性并增强肿瘤根除。为了验证这一 假设，我们将1）选择最有效的肽用于锚定转录的基因产物 并使用我们的高通量体内筛选系统从注射的基因翻译到肿瘤中; 2） 确定肿瘤血管锚定IL-12电基因疗法治疗肿瘤的疗效 免疫活性荷瘤小鼠和自发荷瘤猫中的肿瘤;和3）测试a IL-12抑制肿瘤血管生成的新机制及肿瘤血管介导的IL-12 增强对肿瘤血管生成的抑制。我们提出的实验具有很高的概率 因为我们有一个很好的模型系统，可以获得自发性肿瘤， 携带大型动物和完成任务所需的所有资源。

Great effort has been made in developing tumor-targeted gene delivery, but no attention has been given to targeting the therapeutic gene products that are transcribed and translated from genes transfected in normal tissues into tumors. Targeting gene product in tumors is very important for systemic gene delivery because only a portion of genes are successfully delivered into tumors by using the most successful systemic tumor-targeted gene delivery technology. Targeting gene product in tumors is also important for intratumoral gene delivery because the most commonly used therapeutic genes like TRAIL yield soluble proteins that are secreted into the blood circulation and are harmful to normal cells. Moreover, some gene products such as IL-12 are more effective when co-localized with tumors, compared to systemic localization (Li,S., JNCI, 2002; Li, S., Mol Therapy, 2005). In this application, the applicant will select the effective tumor vessel-targeted peptides to target or anchor the therapeutic gene product transcribed and translated from the injected gene into tumors. Specifically, tumor vessel- anchored IL-12 gene encoding the selected tumor vessel-anchored mini-peptide and IL-12 will be generated and will be administered into tumors via electric pulses to achieve the tumor-targeted gene delivery and the tumor-targeted gene-product auto-delivery. The hypothesis is that the increased IL-12 accumulation in tumor and reduction of IL-12 circulation in serum by using tumor vessel-anchored IL-12 electrogenetherapy will greatly reduce systemic toxicity and enhance tumor eradication. To test this hypothesis, we will 1) select the most effective peptides for anchoring gene product that are transcribed and translated from the injected gene into tumors using our high throughput in vivo screening system; 2) Determine the therapeutic efficacy of tumor vessel-anchoring IL-12 electrogenetherapy for treating tumors in immunocompetent tumor-bearing mice and spontaneous tumor bearing felines; and 3) test a novel mechanism by which IL-12 inhibits tumor angiogenesis and by shich tumor vessel-anchoredIL-12 enhances the inhibition of tumor angiogenesis. The experiments that we propose have a high probality of success because we have an excellent model system in place, the access to spontaneous tumor- bearing large animals, and all the resources necessary to complete the task.