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

本研究的目的是通过转染siRNA来敲除各种放射抵抗肿瘤的放射敏感性相关基因（ATM、hSMG 1等），改变其放射敏感性，提高放射治疗效果，为将来的基因放射治疗提供依据。放射抗性肿瘤小鼠，检测其基因产物数量的变化、生长曲线的变化及放射敏感性的变化。采用肝细胞癌移植法制备放射抗性肿瘤小鼠，采用恶性淋巴瘤移植法制备放射敏感性肿瘤小鼠。综合考虑肿瘤的粘性和宽度，确定能使肿瘤细胞凋亡而不坏死的照射剂量。我们用伽马射线照射每只小鼠。用TUNEL法检测照射前后各小鼠细胞凋亡的发生情况，用实时荧光定量PCR法检测ATM和hSMG1基因产物的数量变化。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，将设计好的靶向ATM和hSMG1基因的siRNA转染到肿瘤中，（TransIT In Vivo Polymer Solution），并用TUNEL法检测转染和照射前后细胞凋亡的发生，用实时荧光定量PCR方法检测ATM和hSMG1基因产物的数量变化。在ATM和hSMG 1基因敲除组中，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.