表达白细胞介素-12质粒DNA抗小鼠肝癌皮下移植瘤的作用

Antitumor efficacy of naked DNA expressed murine IL-12 in a murine hepatocellular carcinoma model

目的:探讨瘤内注射mIL-12质粒DNA抗小鼠肝癌皮下移植瘤的作用。方法:构建真核表达质粒载体pDC511mIL-12,ELISA方法检测质粒载体在真核细胞中的表达,淋巴母细胞增殖法检测mIL-12的生物学活性;分别于小鼠肝癌H22皮下移植瘤内直接注射质粒DNA,观察各组小鼠存活时间、肿瘤体积变化及各组小鼠脾脏细胞毒T淋巴细胞(CTL)的活性。注射质粒DNA后1月进行瘤体组织病理学观察。结果:mIL-12基因治疗组与空载体对照组相比,肿瘤生长显著受抑制(F=4.10,P=0.03),小鼠存活期显著延长(X2=4.48,P=0.03),并且小鼠脾细胞CTL杀伤活性增强。质粒DNA瘤内注射1月后,pDC511mIL-12组肿瘤病灶炎性细胞浸润明显,病灶内肿瘤细胞广泛坏死。结论:瘤内注射mIL-12表达质粒DNA可抑制小鼠肝癌皮下移植瘤生长,能提高机体抗肿瘤免疫应答。

Purpose: To investigate the antitumor efficacy of intra-tumoral administration of plasmid DNA expressing mIL-12 in murine H22 liver tumor models grafted subcutaneously. Methods: Plasmid encoding mIL12 was constructed and examined the expression of cytokine in the eukaryotic cell through enzyme-linked immunosorbent assay (ELISA). The proliferation assay of T lymphoblasts was performed for measuring the biological activity of expressed mIL12. After intra-tumoral administration of plasmid DNA, mean diameters of the tumor mass and survival time were measured in each murine models group. Lactic dehydrogenase ( LDH) assay was performed to examine whether or not treatment with different plasmid DNA could induce systemic cytolytic activity of lymphocytes against parental H22 cells. Histopathological analysis was operated after administration of plasmid DNA vectors in each murine model group. Results: Growth of liver tumor was significantly inhibited( F =4. 10, P =0. 03), and activity of CTL against H22 was enhanced in mIL12 gene therapy group as compared with the control group. In the focal treated with pDC511mIL12 plasmid DNA, inflammatory cell infiltration was more extensive and necrosis was more definite than control group at 1 month after DMA injection. Conclusions: Intra-tumoral administration of plasmid DNA encoding interleukin-12 could inhibit the growth of H22 liver tumor and induce the host antitumor immune response efficiently in the murine model.