IL-17体内外抗肿瘤作用及其机制研究

目的研究IL-17体内外抗肿瘤作用及其机制,为IL-17基因疫苗进入临床提供实验依据。方法建立稳定转染小鼠IL-17全长基因的小鼠乳腺癌细胞(4T1/IL-17)及相应的对照细胞(4T1/pcDNA3.1、4T1),MTS法检测3种细胞的体外增殖情况;流式法检测3种细胞表面MHCI、MHCⅡ、LFA-1分子表达的变化及3种细胞的凋亡情况。建立荷瘤动物模型,观察3种细胞移植瘤在小鼠体内成瘤性、生长情况及小鼠生存期的变化。接种肿瘤细胞6周后分别检测3组小鼠脾细胞CTL杀伤活性、脾细胞增殖情况。用ELISA法检测小鼠脾细胞经刺激后产生IFN-γ、IL-12的情况;流式细胞技术检测4T1/IL-17细胞接种于小鼠体内的细胞凋亡情况及肿瘤组织细胞表面MHCI、MHCⅡ、LFA-1等分子表达的变化。结果转染IL-17基因后在体外对4T1/IL-17、4T1/pcDNA3.1和4T1细胞的增殖;MHCI、MHCⅡ、LFA-1分子表达;细胞凋亡无影响。将4T1/IL-17细胞接种小鼠体内后,荷瘤小鼠的肿瘤生长速度、体积均明显小于4T1/pcDNA3.1细胞组及4T1细胞组,生存时间也明显延长(P<0.05);肿瘤细胞凋亡率明显增高(P<0.05);细胞表面MHCI、MHCⅡ、LFA-1分子表达水平显著性增高(P<0.01);CTL杀伤活性及对ConA刺激的细胞增殖反应性均明显升高(P<0.01);可产生高水平的IFN-γ、IL-12,有显著性差异(P<0.01)。结论 IL-17在体外未显示抗肿瘤作用,IL-17在小鼠体内具有明显的抗肿瘤作用,其抗肿瘤作用与促进肿瘤细胞细胞凋亡及增强机体免疫应答有关。

Antitumor effects of IL-17 in vitro and in vivo

To investigate the effects of interleukin-17 on tumor,we transfected interleukin-17 gene into mouse breast cancer cells(4T1) and set up an animal model in tumor.By plasmid vector,IL-17 gene was transfected into 4T1 and stable clones expressing IL-17(4T1/IL-17) were obtained by selecting with G418.Meanwhile,empty plasmid vector(pcDNA3.1) and 4T1 cells were transfected as control groups.The proliferation of cells in vitro was detected by MTS.Flow cytometry was used to analyze the expressions of MHCI,MHCⅡ,and LFA-1 molecular on the surface of 4T1/IL-17,4T1/pcDNA3.1,and 4T1 cells.4T1/IL-17,4T1/pcDNA3.1,and 4T1 cells were subcutaneously inoculated into mice respectively and the tumor volume and the survival time were observed.Cell apoptosis and the expression of the MHCI,MHCⅡ and LFA-1 molecules on the surface of tumor cells were analyzed by flow cytometry.LDH release and MTS were used to determine CTL activity and proliferation of the splenocytes respectively.The production of IFN-γ and IL-12 from splenocytes was detected by ELISA.Our data showed that the growth of 4T1/IL-17 cell was similar to 4T1 cell and 4T1/pcDNA3.1 cell in vitro(P > 0.05).Moreover there were no differences of expression of MHCI,MHCⅡ and LFA-1 molecular in 4T1/IL-17,4T1/pcDNA3.1,4T1 cells(P > 0.05).And there was no difference of cell apoptosis rate in 4T1/IL-17,4T1/pcDNA3.1,and 4T1 cells in vitro(P > 0.05).Our data also showed that the growth of tumor in mice inoculated with 4T1/IL-17 cells was significantly retarded(P < 0.05),and the survival time was longer compared to 4T1/pcDNA3.1 and 4T1 groups(P < 0.05).In the mice of inoculation,cell apoptosis rate of 4T1/IL-17 group was higher than those of 4T1/pcDNA3.1 and 4T1 groups(P < 0.05).The expression of MHCI,MHCⅡ,and LFA-1 molecules in the tumor tissues from 4T1/IL-17 inoculated mice were also higher than two other groups(P < 0.01).We also found that the CTL activity and proliferation of the splenocytes from 4T1/IL-17 inoculated mice was higher than those of 4T1/pcDNA3.1 and 4T1 groups(P < 0.01).And the splenocytes from the mice inoculated with 4T1/IL-17 cells could secret higher level of IFN-γ and IL-12 compared with two other groups(P < 0.01).These findings indicated that the gene transfection of IL-17 had no effect on cell growth and apoptosis in vitro;but in the mice inoculated with 4T1/IL-17 and IL-17,the immune function and the antitumor activity could enhance.