IL-18基因转染大肠癌细胞及对其肿瘤原性改变的研究

Interleukin-18 gene transferred into human colon cancer cells reduces tumorigenicity in vivo

目的:建立转染人白细胞介素-18(hIL-18)基因的大肠癌细胞株,并研究IL-18基因转染后SW480细胞肿瘤原性的改变。方法:将携带hIL-18的质粒pcDNA3.1-hIL-18转导入人大肠癌细胞系SW480细胞中,通过药物G-418进行筛选,利用RT-PCR和ELISA法对IL-18的表达进行检测;通过裸鼠致瘤实验观察肿瘤原性的改变。结果:IL-18基因成功转导入SW480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个转染细胞在24 h内分泌IL-18的含量是(145.71±4.42)pg;空载体转染的细胞未检测到hIL-18;生长曲线显示转染hIL-18基因后的细胞生长明显减慢;黏附曲线显示SW480-hIL-18组的黏附率在各个时相点均明显升高,而空载体组和空白对照组之间差异无统计学意义(P<0.05)。裸鼠致瘤实验表明,接种SW480-hIL-18细胞的裸鼠肿瘤体积明显小于SW480组和SW480-pcDNA3.1组;抗瘤实验结果显示,放射灭活的SW480-pcDNA3.1细胞和SW480-hIL-18细胞免疫接种裸鼠后,再接种SW480细胞于裸鼠左侧背部皮下,SW480-hIL-18细胞免疫接种组肿瘤长出的时间比SW480-pcDNA3.1细胞免疫接种组明显延长,并且肿瘤的生长速度明显低于SW480细胞免疫接种组。结论:hIL-18基因能成功整合到SW480细胞基因组中,并且能在转染的肿瘤细胞中持续表达。hIL-18基因转导后的SW480细胞生长受到抑制,黏附能力增强h,IL-18基因转染降低了SW480细胞的肿瘤原性;hIL-18基因修饰的SW480细胞具有明显的抗肿瘤作用,为大肠癌基因工程肿瘤疫苗的研制提供了实验基础。

Objective：To study the effects of interleukin-18 gene transfection on tumorigenesis of human colorectal cancer cell line SW480.Methods： We transfected SW480 cells with a mammalin expression vector containing the human IL-18 complementary DNA.The biological expression of rhIL-18 was tested by RT-PCR and ELISA method;nude mice were injected with SW480 cells with or without the hIL-18 gene.Results： The hIL-18 cDNA was successfully integrated into SW480 cells,it was（145.71±4.42） pg hIL-18 cytokine secreted by one million transduced SW480 cells in 24 hours.In vivo tumor growth curves,based on measured tumor size,SW480,SW480-pcDNA3.1 and SW480-IL-18 resulted in tumor formation 8-11 days after injection.The growth rate of SW480-IL-18 in vivo was significantly slower than those of SW480 and SW480-pcDNA3.1 cells.Tumor formation by parental SW480 cells was significantly delayed in mice those had been immunized with irradiated SW480-IL18 cells.Conclusion： The findings indicated that human colon cancer cells were successfully modified by the gene of IL-18 cytokine and can reduce their tumorigenicity.The SW480 cells transduced with IL-18 gene might be used as human colon cancer vaccine.