131I偶联人端粒酶逆转录酶-siRNA对肝细胞癌放射基因治疗的实验研究

研究发现在肝癌的发生过程中，多个基因和多个胞内信号通路的改变才能表现出临床症状，但任一技术对肿瘤患者的生存率改善都有限，因此肿瘤的综合治疗仍是目前的发展方向，放射基因联合治疗是近年来的研究热点之一。申请者在前期研究中对肿瘤的内照射治疗和RNA干扰分别进行系列的研究，已合成和优化了靶向人端粒酶逆转录酶的siRNA，构建了纳米尺寸的靶向性可降解基因载体双硫键交联的聚乙酰亚胺（SS-PEI-cRGD），实验验证了siRNA@SS-PEI-cRGD的生物效应。为进一步研究，本课题拟采用131I标记核苷酸的技术直接标记siRNA，这样不仅可以利用基因载体的靶向技术将131I和siRNA同时递送到靶细胞，而且在siRNA与靶基因特异性结合时，使131I同时结合于靶位点，提高对靶基因辐射的目的，131I和siRNA协同作用抑制靶基因的表达和肿瘤的生长。这一研究模式对发展放射基因治疗具有重要的实际意义。

Recent research has demonstrated that clinical symptoms of liver cancer develop only when multiple genes and multiple intracellular signaling pathways undergo changes simultaneously. As the efficacy of any one technique available is limited in improving the survival of tumor patients, comprehensive treatment remains the main current trend of development. Combined radiation and gene therapy is the focus of cancer research in recent years. In the preliminary study on tumor internal radiotherapy and RNA intervention, the applicant synthesized and optimized the targeting human telomerase reverse transcriptase siRNA, established a nano-sized, targeting, biodegradable and disulfide cross-linked polyethylenimine gene carrier (SS-PEI-cRGD), and demonstrated the biological effect of siRNA@SS-PEI-cRGD. The present study was intended to use nucleotide 131I-labeling technique to directly label siRNA so that 131I and siRNA could be transmitted simultaneously to target cells by using the carrier gene targeting technique. In addition, 131I could bind onto the target site during specific binding of siRNA with the target gene so as to raise the effect of radiation on the target gene by taking advantage of the synergic effect of 131I and siRNA to inhibit the target gene expression and tumor growth. This research model would be of practical significance in developing combined radiation and gene therapy.