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

我们的研究目的是转染各种耐辐射肿瘤的辐射敏感性基因sirna，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。我们转染拟敲低辐射耐药肿瘤小鼠的辐射敏感性基因（ATM、hSMG1等）的sirna，观察其基因产物量的变化、生长曲线的变化及辐射敏感性的变化。我们通过移植肝炎细胞癌制成辐射耐药肿瘤小鼠，通过移植恶性淋巴瘤制成辐射敏感肿瘤小鼠。考虑肿瘤的黏性和宽度，确定辐照剂量，使小鼠在不发生坏死的情况下适当凋亡。我们用伽马射线照射每只老鼠。采用TUNNEL法检测各组小鼠辐照前后细胞凋亡的发生情况，采用real-time PCR法检测ATM和hSMG1基因产物数量的变化。ATM和hSMG1基因产物与细胞凋亡的发生相关。另一方面，我们利用体内siRNA转染试剂（TransIT in vivo Polymer Solution）将拟敲除ATM或hSMG1基因的siRNA转染到肿瘤中，并采用TUNNEL法检测转染前后及照射后细胞凋亡的发生情况，采用real-time PCR法检测ATM和hSMG1基因产物的数量变化。在敲除ATM和hSMG1基因的组中，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.