吲哚胺2,3-双加氧酶上调人肝癌细胞人类白细胞抗原-G的表达

目的:探讨人类吲哚胺2,3-双加氧酶（indoleamine 2,3-dioxygenase,IDO）对肝癌细胞人类白细胞抗原-G（humanleucocyte antigen-G,HLA-G）表达的影响。方法:用脂质体lipofectamine^TM2000将pcDNA3.1-IDO重组质粒稳定转染入肝癌SMMC-7721细胞作为实验组（pcDNA3.1-IDO质粒转染组）,同时设置空载体对照组（pcDNA3.1转染组）和空白对照组（未转染组）,用RT-PCR和Western blot鉴定实验组和2个对照组细胞IDO mRNA和蛋白的表达,然后分别给予实验组细胞IDO的抑制剂(2.5 mmol/L 1-D-MD和底物（200μmol/L L-色氨酸）干预48 h,进一步用实时荧光定量PCR和Westernblot检测上述5组细胞中HLA-G mRNA和蛋白的表达水平。结果:RT-PCR和Western blot显示空载体对照组和空白对照组未见IDO表达,而实验组细胞高表达IDO。实时荧光定量PCR和Western blot结果显示,实验组HLA-G mRNA和蛋白表达水平较空载体对照组和空白对照组均明显上调（P均<0.05）,给予1-D-MT和L-色氨酸干预后此效应可逆转。结论:在肝癌SMMC-7721细胞,IDO可以上调HLA-G的表达,色氨酸降解途径参与了此调节过程。

Indoleamine 2, 3-dioxygenase up regulates the expression of human leucocyte antigen.G in hepatocellular carcinoma cells

OBJECTIVE： To investigate the effect of indoleamine 2, 3-dioxygenase（IDO） on the expression of human leucocyte antigen-G（HLA-G） in hepatocellular carcinoma cells. METHODS： Hepatocellular carcinoma cells SMMC-7721 transfected with pcDNA3.1- IDO recombinant plasmid by lipofectamine 2000 reagent as experimental group （pcDNA3.1-IDO group）, SMMC-7721 transfected with blank plasmid（ pcDNA3.1 group） and blank SMMC-7721 （nontransfected group） were used as control groups. The expression of IDO in expreimental group and control groups were tested by RT-PCR and Western blot, the expression of HLA-G mRNA and protein in cells were tested by real time fluorescence quantitative PCR and Western blot. Then pcDNA3.1-IDO plasmid group cells were treated with IDO competitive inhibitior（ 1- methyl-D-trypophan） and its substrate （L-tryptophan） intervention to investigate the effect of drugs on the expression of HLA-G. RESULTS： IDO was highly expressed in pcDNA3.1-IDO plasmid group cells shown by RT-PCR and Western blot. Expression of HLA-G mRNA and protein in pcDNA3.1-IDO plasmid group were higher than the other control groups, the intervention of L-tryptophan and 1-methyl-D-trypophan could reverse this effect. CONCLUSION： IDO could up regulate the expression of HLA-G in SMMC- 7721 cells with tryptophan degradation pathway involved in this regulation.