南京医科大学学报（自然科学版）2012，Vol.32Issue(5)：659-663,5.
肺癌细胞抑制CD4+T细胞IFN-γ基因表达的机制研究
The mechanism of downregulation of IFN-γ expression in CD4+T cells by lung cancer cells
摘要
Abstract
Objective;To investigate whether lung cancer cells can directly influence the methylation of IRN-7 gene promoter in CD4T cells. Methods;The plasma level of IEN-γ was determined by ELISA in the lung cancer patient group(n = 30) and healthy control group(n = 30). CD4T cells were isolated by CD4-positive isolation kil from peripheral blood of lung cancer patients (n = 8) and healthy controls (n = 8),and genomic DNA was extracted using Q1Aamp Mini Kit and bisulfite treated. IFN-γ gene promoter methylalion was analyzed with methylalinn specific sequencing method and the result was analyzed by bioinformatics software;A Transwell culturing system was also established(n = 6). CD4+ T cells of healthy volunteers were co-cultured with SPC-AI as the experimental group and CD4+ T cells cultured as the control group. After culturing for 5 d,Cl)4+ T cells were collected to analyze IFN-7 gene promoter methylution using methvlation specific sequencing method as described above. Meanwhile, CD4+ T cells were stimulated by anti-CI)3 and nnti-CI)2K antilxidies for 6 and 24 h. The IFN-7 of supernatant was delected by EIISA and RT-PCR was used to determine the mRNA transcript levels of IFN-γ. Results; The level of plasma IFN-γ was significantly lower in lung cancer patients(69.30 ± 38.56 pg/ml vs 92.62 ± 34.75 pg/ml,P= 0.017). The hypermelhylation status of IFN-7 promoter in CD4+ T cells of lung cancer patients wan 84.6%(controll,68.6%)(P < 0.001). The concentration of plasma IFN-7 was negatively correlated with the percentage of methylalion at the IFN-γ promoter in the patient group(r = -0.850 3,P = 0.010 7). In Transwell culluring system,after stimulation for 6 and 24 h.the expression of IFN-7 in the experimental group was significantly lower than that of the control group [6 h:( 14.53 ± 7.12) pg/ml vs (36.14 ± 23.51) pg/ml,24 h:(7.81 ± 4.02) pg/ml vs (24.85 ± 15.58) pg/ml]. The mRNA transcript levels of IFN-γ of the control groups were increased 2.37 fold after stimulation for 6 h. The hypermethylation status of the IFN-7 promoter in CD4+ T cells of the experimental group was 85.4%(control,70.9%). Conclusion:Lung cancer cell can induce the hyperme-thylation of IFN-7 gene promoter, which dcwnregulates the expression of the IFN-7 gene,and it may play an important role on the im-munosuppression of lung cancer patients.关键词
DNA 甲基化/干扰素-γ/CD4+T细胞/肺癌细胞Key words
DNA methylation/ IFN-γ/ CD4+ T cells/ lung cancer cell分类
生物科学引用本文复制引用
秦雪君,谢而付,高丽,庞智睿,潘世扬,王芳,彭蘡,徐娟,韩月,孙瑞红,张丽霞,王宏..肺癌细胞抑制CD4+T细胞IFN-γ基因表达的机制研究[J].南京医科大学学报（自然科学版）,2012,32(5):659-663,5.基金项目
国家自然科学基金(30972821,30901344,30901262),江苏省实验诊断学重点实验室基金(XK201114) （30972821,30901344,30901262）
