巨噬细胞炎症蛋白1α修饰的小鼠肺癌疫苗的制备及体内抗肿瘤活性研究

Preparation of murine lung cancer vaccine modified by macrophagic inflammatory protein 1αand observational study of antitumor activity in vivo

目的以小鼠趋化因子巨噬细胞炎症蛋白1α(MIP-1α)的重组腺病毒载体(AdmMIP-1α)体外感染小鼠Lewis肺癌细胞株(LLC),观察其体内抗肿瘤活性,探讨其成为肺癌疫苗的可能性。方法AdmMIP-1α体外感染LLC细胞,通过绿色荧光蛋白(GFP)的表达检测感染率。连续14 d隔天进行细胞计数,观察细胞的体外生长曲线。取3×106修饰后的LLC细胞接种于C57BL／6小鼠,4周后在MIP-1α瘤苗组未荷瘤小鼠原接种部位的对侧再接种1×106野生型LLC或小鼠淋巴瘤细胞株(EL4)细胞。观察肿瘤体积。结果AdmMIP-1α能有效感染靶细胞LLC细胞,感染后LLC细胞的体外生长无明显改变。修饰后LLC细胞的体内成瘤性下降;4周后再接种LLC细胞,肿瘤生长速度明显减慢;而再接种的EL4细胞呈渐进性生长,与对照组无明显差异。结论表达MIP-1α基因的LLC细胞的体内成瘤性下降,并且能激发特异性免疫保护反应,有可能成为有效的肺癌疫苗。

Objective To appraise the antitumor activity in vivo of murine lung tumor vaccine expressing macrophagic inflammatory protein 1α（MIP-1α） mediated by recombinant adenoviral vector. Methods The infectivity efficacy of Lewis lung carcinoma （LLC） in vitro was measured by green fluoreserit protein （GFP） expression after infected by AdmMIP-1α, a recombinant adenoviral vector carrying murine MIP-1α, and the number of cells were counted every other day for 14 days. 3 × 10^6 MIP-1α modified LLC cells were subcutaneously inoculated to C57BL/6 mice and the tumor-free animals were rechallenged by 1 × 10^6 wild-type LLC cells or syngenic EL4 cells four weeks later. The tumor volume was measured twice a week. Results Adenoviral vectors could efficiently infect LLC cells in vitro, and proliferation of these transfectants demonstrated similar speed of growth in vitro. Injection of MIP-1α modified LLC tumor cells led to significantly slow down of the tumor growth and prolong the survival in mice in comparison to those injected with either cytomegalvirus （CMV） promoter driven GFP or the parental tumor cells. Rechallenge of the tumor-free mice four weeks after administration of AdmMIP-1α with the parental LLC cells resulted in significant inhibition of tumor growth, while there was no difference shown rechallenged in syngenic EL4. Conclusions Lung cancer cells expressing MIP-1αmediated by recombinant adenovirai vector can decrease tumorigenicity and elicit specific immunological protection, providing potential to develop anti-cancer therapy.