The research about the application of RNAi phenomenon to radiation therapy : using hSMG1-siRNA

本研究的目的是将辐射敏感性相关基因的siRNAs导入各种耐辐射肿瘤，改变其辐射敏感性，提高放射治疗效果，并将这些数据用于未来的基因放射治疗。对荷辐射肿瘤的小鼠，检测其基因产物的数量变化、生长曲线的变化及辐射敏感性的变化。我们综合考虑肿瘤的粘连性和宽度，确定了合适的照射剂量，使小鼠有适当的细胞凋亡而不发生坏死。我们对每只小鼠进行了伽马射线照射。用隧道法检测照射前后各组小鼠细胞的凋亡情况，用实时荧光定量聚合酶链式反应检测ATM和hSMG1基因产物的数量变化。另一方面，利用体内siRNA转染剂将计划敲除ATM或hSMG1基因的siRNAs导入肿瘤细胞，用隧道法检测转染前后及照射后细胞凋亡的发生情况，并用实时荧光定量聚合酶链式反应方法检测ATM和hSMG1基因产物的数量变化。在ATM和hSMG1基因被敲除的组中，细胞凋亡的发生减少。

It is the purpose of our research that we transfect siRNAs of genes about radiation sensitivity to various radiation-resistant tumor, change their radiation sensitivity, enhance radiation therapy effect and utilize this data for future gene-radiation therapy.We transfected siRNAs planed to knock down genes about radiation sensitivity (ATM, hSMG1 et.) to mice with radiation-resistant tumor, and checked the change of quantity of their gene product, the change of growth curve and the change of their radiation sensitivity We made mice with radiation-resistant tumor by transplanting hepatitis cell carcinoma, and made mice with radiation-sensitive tumor by transplanting malignant lymphoma. We considered stickiness and width of tumor and decided the radiation dose which made a proper apoptosis without necrosis on the mice. We irradiated gamma ray to each mice. We checked the occurrence of apoptosis on each mice before and after the irradiation with TUNNEL method, and checked the change of quantity of ATM and hSMG1 gene products with real-time PCR method. ATM and hSMG1 gene products correlated with the occurrence of apoptosis.On the other hand, we transfected siRNAs planed to knock down ATM or hSMG1 genes into tumors using in vivo siRNA transfection regent (TransIT In Vivo Polymer Solution), and checked the occurrence of apoptosis before and after the transfection and the irradiation with TUNNEL method, and checked the change of quantity of ATM and hSMG1 gene products with real-time PCR method. In the groups knocked down ATM and hSMG1 gene, the occurrence of apoptosis decreased.