联合应用新城疫病毒及其 HN基因对小鼠黑色素瘤抑制效应的研究

背景与目的:尽管新城疫病毒( Newcastle disease virus, NDV)对多种肿瘤具有抑制作用 ,但其抑瘤机制尚不完全清楚.以前的研究结果表明,该病毒的血凝素神经氨酸酶( hemagglutinin-neuraminidase,HN)基因在该病毒的抗肿瘤作用上发挥重要作用且 HN蛋白表达后能够定位于肿瘤细胞膜上,以 HN蛋白作为肿瘤细胞的外源抗原来研究其抑瘤作用尚未见报道.本研究拟探讨 HN蛋白作为外源抗原在新城疫病毒抗肿瘤的作用以及二者联合应用对小鼠黑色素瘤的抑制效应.方法:在 C57BL/6小鼠右后肢皮下接种 B16黑色素瘤细胞 2× 105个.荷瘤第 2天,左后肢肌肉注射含新城疫病毒 HN基因的重组质粒,荷瘤第 7天,瘤内注射新城疫病毒 2× 109pfu;同时设单独 HN基因或 NDV治疗组及注射 PBS的对照组.通过抑瘤率观察动物体内的抑瘤效果;通过特异性细胞毒 T淋巴细胞( cytotoxic T lymphocyte,CTL)实验, ICAM Ⅰ、 CD48及新城疫病毒 HN蛋白在肿瘤细胞表面表达检测,探讨 HN蛋白所介导的抑瘤作用.结果:联合应用新城疫病毒及该病毒 HN基因对肿瘤的抑制效果明显好于单独 HN基因及新城疫病毒,抑瘤率达 82.8%,特异性 CTL反应增强,对靶细胞的杀伤率为 18.4%;单独 HN基因及新城疫病毒治疗组的抑瘤率分别为 56.6%、 41.0%,特异性 CTL活性分别为 4.4%、 10.1%;瘤内注射 NDV的肿瘤细胞表面检测到 HN分子的表达, ICAM Ⅰ、 CD48分子表达上调.结论:定位于肿瘤细胞表面的 HN蛋白介导机体对肿瘤细胞的特异性杀伤,联合应用新城疫病毒及该病毒 HN基因显著增强了机体对肿瘤细胞的杀伤效应.

Antitumor research on mouse melanoma with combined application of Newcastle disease virus and its HN gene

BACKGROUND & OBJECTIVE: Although Newcastle disease virus (NDV) shows antitumor effect on many tumors, its mechanism is unclear. Hemagglutinin-neuraminidase (HN) gene was found to play an important role in NDV antitumor effect and HN protein located on tumor cell surface. This research was to evaluate the possibility of HN protein as a foreign antigen of tumor cell and the antitumor effect of the combined application of HN gene and NDV. METHODS: C57BL/6 mice were subcutaneously inoculated with 2 x 10(5) B16 tumor cells in the right hindlimb. Combination group: on 2nd day post-inoculation, the recombinant plasmid containing HN gene was injected intramuscularly in the left hindlimb; on 7th day post-inoculation, 2 x 10(9) pfu NDV was administrated intratumorally. The alone HN gene group, NDV group, and PBS control group were treated as above. The antitumor effect was observed through tumor suppression rate, the antitumor mechanisms were researched with specific cytotoxic T lymphocyte (CTL) assay, and the expression determination of HN protein, ICAM-I, and CD48 on the B16 tumor cells. RESULTS: The antitumor efficacy of the combined application of NDV and its HN gene increased compared with NDV,and its HN gene alone, the tumor suppression rates were 82.8%, 41.0%, and 56.6%; the specific CTL activity were 18.4%, 10.1%, and 4.4%, respectively. Furthermore, the expression of HN gene had been detected, and the expression of ICAM-I and CD48 were up-regulated on the tumor cells after NDV injection. CONCLUSION: HN protein located on the surface of tumor cells and mediated the specific repulsion to tumor cells; the antitumor efficacy increased after the combined application of NDV and its HN gene.