杆状病毒介导NIS基因放射治疗甲状腺癌的实验研究

目的探讨重组钠／碘同向转运体(NIS)基因杆状病毒介导甲状腺癌细胞放射性碘治疗的可行性。方法构建杆状病毒载体质粒(pFBNIS)并制备重组NIS杆状病毒(BacNIS)，体外感染甲状腺癌细胞，通过免疫荧光检测NIS蛋白的表达，通过动态摄碘及NaC104摄碘抑制实验观察表达蛋白的功能和特性；进行^131I杀伤细胞的克隆形成实验。结果成功构建了重组NIS杆状病毒，受巨细胞病毒(CMV)极早期基因启动子调控；BacNIS体外感染的甲状腺癌细胞表达的NIS蛋白具有摄碘功能和NaC104抑制的特性；BacNIs感染的肿瘤细胞可被^131I有效杀伤。结论BacNIS是介导肿瘤细胞摄碘的有效方法，为杆状病毒介导NIS基因治疗失分化甲状腺癌转移灶提供依据。

Experimental study of baculovirus-mediated transfer of the thyroid sodium/iodide symporter gene into thyroid cancer for targeted radiotherapy

Objective To explore the radiotherapy of thyroid cancers by delivering the sodium/iodide symporter (NIS) gene into the tumor cells using baculoviral vector. Methods The recombinant baculovirus encoded human NIS gene (BacNIS) was constructed under the control of the cytomegalovirus promoter. Using a mouse monoclonal antibody and a fluorescein isothiocyanate (FITC) labeled antimouse antibody to confirm the expression of the NIS protein of infected tumor cells by immunofluorescence. In vitro iodide uptake experiments were carried out on BacNIS-infected tumor cells to further characterize the BacNIS virus, and the cell killing with ~131 I and clonogenic assay were performed on BacNIS-infected cell to observe the selective killing effect of ~131 I on NIS-expressing cells. Results Infection of thyroid cancer cells (FTC-133, W3) with BacNIS resulted in elevating perchlorate-sensitive ~125 I uptake of these cells to a higher level than that in noninfected cells. But ~125 I uptake of 8505C was very low. It was demonstrated that the BacNIS vector did function in tumor cells. In addition, BacNIS-infected tumor cells were selectively killed by exposure to ~131 I, as revealed by clonogenic assays and the cell-killing rate was higher than that in nontreated tumors. Conclusion BacNIS is very efficient in triggering iodide uptake of infected tumor cell, and it is outlining the potential of this novel cancer gene therapy.