论文部分内容阅读
[目的]观察苯并[a]芘(BaP)诱导人支气管上皮细胞(16HBE)恶性转化过程中基因组总体DNA甲基化水平的改变。[方法]采用40.0μmol/L BaP长期诱导16HBE细胞,构建恶性转化细胞模型,分别采用5-甲基胞嘧啶免疫荧光和高效毛细管电泳技术从定性和定量的角度动态检测细胞全基因组总体DNA甲基化水平的变化趋势,同时监测DNA甲基转移酶的活性改变。[结果]在BaP诱导16HBE细胞3、6、9、12、15及18周过程中,细胞基因组DNA总体甲基化水平呈时间依赖性降低;定量分析结果显示,正常16HBE细胞基因组DNA总体甲基化百分比(mCpG%)为(4.78±0.58)%,各诱导阶段细胞的mCpG%值分别为(4.62±0.39)%、(3.82±0.39)%、(4.07±0.40)%、(3.27±0.31)%、(2.63±0.21)%和(2.48±0.15)%。随着诱导时间的延长,16HBE细胞中总体甲基转移酶活性也呈逐渐降低的趋势。[结论]基因组总体DNA甲基化水平进行性降低是BaP诱导16HBE细胞恶性转化过程中的重要特征,DNA甲基转移酶活性的降低是导致细胞基因组DNA总体甲基化水平降低的主要原因。
[Objective] To observe the change of DNA methylation level in genomic DNA during the malignant transformation of human bronchial epithelial cells (16HBE) induced by benzo [a] pyrene (BaP). [Method] The 16HBE cells were induced by 40.0μmol / L BaP for a long time to construct the malignant transformed cell model. The 5-methylcytosine immunofluorescence and high performance capillary electrophoresis were used to detect the total DNA methyl of the whole genome qualitatively and quantitatively The level of change trend, while monitoring DNA methyltransferase activity changes. [Result] The overall methylation level of genomic DNA was decreased in a time-dependent manner at 3, 6, 9, 12, 15 and 18 weeks after BaP-induced 16HBE cells. Quantitative analysis showed that the overall genomic DNA of 16HBE cells (4.78 ± 0.58)% and (4.62 ± 0.39)%, (3.82 ± 0.39)%, (4.07 ± 0.40)%, (3.27 ± 0.31)%, %, (2.63 ± 0.21)% and (2.48 ± 0.15)% respectively. With the extension of induction time, the overall methyltransferase activity in 16HBE cells tended to decrease gradually. [Conclusion] The progressive reduction of genomic DNA methylation level is an important feature of BaP-induced malignant transformation of 16HBE cells. The decrease of DNA methyltransferase activity is the main reason for the decrease of the overall methylation level of genomic DNA.