FOLFOX4与1-D-甲基色氨酸联合治疗对荷胃癌小鼠调节性T细胞的影响

The effect of combining FOLFOX4 with 1-D-methyl tryptophan on regulatory T cells of gastric cancer-bearing mice

目的:研究FOLFOX4与1-D-甲基色氨酸(1-D-methyl tryptophan,1-D-MT)联合应用是否有利于改善荷胃癌小鼠的免疫耐受状态。方法:用脂质体转染法,将pcDNA3.1-IDO质粒和pcDNA3.1(+)空质粒稳定转染MFC细胞,并设未转染组;用RT-PCR和Western blot法检测未转染组、空质粒转染组和pcDNA3.1-IDO转染组IDO mRNA和蛋白的表达;然后建立荷胃癌小鼠皮下移植瘤模型,并设未转染组、空质粒转染组,IDO+生理盐水(NS)组、FOLFOX4组、1-D-MT组和FOLFOX4+1-D-MT联合处理组,采用流式细胞术检测各组小鼠脾脏中Treg细胞数量变化;RT-PCR检测FOXP3 mRNA表达量变化。结果:IDO mRNA与蛋白表达在稳定转染pcDNA3.1-IDO质粒组细胞较未转染组、空质粒转染组表达量明显增加(P<0.05)。IDO+NS组小鼠脾脏Treg细胞比例及FOXP3 mRNA含量较未转染组、空质粒组均明显增多(P<0.05)。FOLFOX4+1-D-MT组和1-D-MT组与FOLFOX4组相比,Treg细胞比例及FOXP3 mRNA含量均明显降低(P<0.05),且联合治疗组较1-D-MT组降低更明显(P<0.01)。结论:通过抑制Treg的增殖及降低FOXP3 mRNA表达,FOLFOX4与1-D-MT联合应用可降低机体免疫逃逸能力。

1 OBJECTIVE： To investigate whether combining 1-D-MT with FOLFOX4 could be useful to improve the immune tolerance of gastric cancer-bearing mice. METHODS： By using the lipofectamineTM 2000, the eukaryotie expression plasmid pcDNA3.1-IDO and empty vector peDNA3.1 （＋） were transfected in a MFC cell line, setting a control group. The expression of IDO was detected by reverse transcription polymerase chain reaction（RT- PCR） and western blot. Animal model of gastric cancer-bearing mice were established to receive normal saline （NS）, FOLFOX4, 1-D-MT and 1-D-MT＋FOLFOX4 therapy. By using flow cytometry, Treg cell ratio change was analyzed and FOXP3 mRNA expression change was assessed by RT-PCR. RESULTS： The expression of IDO mRNA and protein in the group trancfected with pcDNA3.1-IDO was obviousely ligher than the MFC group and the empty vector group （P〈0.05）. Treg cell ratio and FOXP3 mRNA expression in the transfected IDO negative control group with NS therapy was higher than the MFC and the empty vector groups（P〈0.05）. The Treg ratio and FOXP3 mRNA in 1-D- MT＋FOLFOX4 and 1-D-MT groups were less than in FOLFOX4 group（P〈0.05）, with 1-D-MT＋FOLFOX4 group more markedly than 1-D-MT group （P〈0.05）. CONCLUSION： Combining 1-D-MT with FOLFOX4 could reduce Treg cell ratio and FOXP3 expression, thus reducing the immune escape.