IL-18基因转导乳腺癌细胞肿瘤原性的改变及抗瘤作用的研究

目的：建立转人白细胞介素-18（IL-18）基因的乳腺癌细胞株Bcap37细胞，并探讨IL-18基因转导后Bcap37细胞肿瘤原性的改变和抗瘤作用。方法：将携带人IL-18的质粒pcDNA3.1-IL-18转导入人乳腺癌细胞系Bcap37细胞中，通过药物G418进行筛选，采用RT-PCR和ELISA法对IL-18基因的表达进行检测；裸鼠致瘤实验观察肿瘤原性的改变；观察灭活后Bcap37-IL-18细胞的抗瘤作用。结果：IL-18基因成功转导入Bcap37细胞中并能顺利表达；RT-PCR 电泳结果显示IL-18基因在mRNA水平有表达；ELISA结果显示,106个转导细胞在24h内分泌IL-18的含量是(126.3±4.5)pg; 空载体转染的细胞未检测到IL-18；裸鼠致瘤实验表明，接种Bcap37-IL-18细胞的裸鼠肿瘤的生长速度明显低于Bcap37组和Bcap37-pCDNA3.1组；抗瘤实验结果显示，放射灭活的Bcap37-pcDNA3.1细胞和Bcap37-IL-18细胞免疫接种裸鼠后，再接种Bcap37细胞于裸鼠左侧背部皮下。肿瘤长出的时间Bcap37-IL-18细胞免疫接种组比Bcap37 pCDNA3.1细胞免疫接种组明显延长，且肿瘤的体积Bcap37-IL-18细胞免疫接种组比Bcap37-pCDNA3.1细胞免疫接种组小。结论: IL-18基因能成功的整合到Bcap37细胞基因组中,且在转导的肿瘤细胞中持续表达；IL-18基因转染降低了Bcap37细胞的肿瘤原性；IL-18基因修饰的Bcap37细胞具有明显的抗肿瘤作用。

In vivo vaccine effect and tumorigenicity of human breast carcinoma cells transfered by interleukin-18 gene

Objective: To study the effect of the interleukin-18 gene transfection on tumorigenesis of the human breast carcinoma cell line Bcap37. Methods: Bcap37 cells were transfected with a mammalin expression vector containing human IL-18 complementary DNA. The biological expression of IL-18 was determined by the RT-PCR and ELISA methods. Nude mice were injected with Bcap37 cells with or without the IL-18 gene. Results: The IL-18 cDNA was successfully integrated into the Bcap37 cells. There were (113.8±4.7)pg IL-18 secreted by one million transduced cells in 24 hours. In vivo tumor growth curves, based on measured tumor size, Bcap37, Bcap37-pcDNA3.1 and Bcap37-IL-18 resulted in tumor formation from 8 to 11 days after injection. The growth rate of Bcap37-IL-18 in vivo was significantly slower than that of Bcap37 and Bcap37-pcDNA3.1 cells. Tumor formation by parental Bcap37 cells was significantly delayed in mice that had been immunized with Bcap37-IL18 irradiated cells. Conclusion: Human breast carcinoma cells were successfully modified by IL-18 cytokine genes and reduced the tumorigenicity. Breast cells transduced with IL-18 genes might be used as human colon cancer vaccines.