白细胞介素18与内皮抑素联合基因导入治疗肿瘤的研究

A study of new antitumor gene therapy of interleukin-18 combined with endostatin gene

目的：选用白细胞介素18（IL-18）和内皮抑素（ES）联合以物理方法导入治疗肿瘤，以探索一种肿瘤基因治疗的新途径。方法：①采用脂质体包被肌肉注射法将作者构建的质粒pSecTag2B-mIL-18和pES1424-mES分别和联合转人Balb／c小鼠，逆转录-聚合酶链反应（RT-PCR）和酶联免疫吸附试验（ELISA）检测两种基因蛋白在动物体内的表达情况；②将小鼠分为4组：pSecTag2B-mIL-18转入组、pES1424-mES转入组、pSecTag2B—mIL-18与pES1424-mES联合转入组和对照组，观察各组肿瘤的生长情况。结果：①RT-PCR和ELISA检测证明两种质粒均能够在小鼠肌肉中表达，特别是将两种质粒同时转入同一小鼠肌肉后，能够同时在小鼠肌肉中表达；并将表达的蛋白分泌到外周血液循环中，分泌量与单独基因转入分泌表达量的差异没有统计学意义。②IL-18、ES单独应用都能明显抑制肿瘤的生长，而两基因联合治疗抑制肿瘤的效果明显好于单基因治疗组。结论：联合IL-18和ES基因治疗比两种基因单独应用能够更好地抑制肿瘤生长。

Objective To explore a new method of tumor treatment using interleukin- 18 （ IL- 18） combined with endostatin to increase effects and decrease side effects of gene therapy. Methods The pSecTag2B- m-IL-18 and pES1424-m-endostatin were constructed by our laboratory , the two naked plasmids were injected into muscle of balb/c mice alone and combined repetitively. The expression status of two genes were tested by RT-PCR and ELISA. In animal experiment, balb/c mice were divided into four groups： endostatin group , IL- 18 group,combining group and control group, 105 of colon26 tumor cells were implanted subcutaneously into every mouse. Two naked plasmids were injected into muscle of balb/c mice alone and combined repectively according to group. The effects of antitumor were observed. Results After transferring of IL- 18 genes alone , serum concentrations of IL-18 were significantly elevated,while interferon （IFN）-gamma also increased in the serum of the mice. After transfection of endostatin gene alone, serum concentrations of endostatin were significantly elevated in level of mRNA and protein. When the two plasmids were transferred into muscle of mice simultaneously, IL-18 and endostatin were also expressed simultaneously in both mRNA and protein level as same as trans- ferred alone. In animal experiment , IL-18 and endostatin gene transferring alone resulted in significant suppression of tumor growth respectively, and more significant suppression of tumor growth was observed when the tumor burdening mice were treated by co-transfection with IL-18 and endostatin genes. Conclusion Co-transferring of IL-18 and endostatin gene can be successfully achieved by intramuscular injection of naked plasmids in vivo, more significant therapeutic outcome are observed than single gene transferring of IL-18 or endostatin.