α粒子诱发永生化人支气管上皮细胞恶性转化过程中DNA甲基化的变化

Changes of gene methylation profile in malignant transformation of immortalized human bronchial epithelial cell line induced by alpha-particle irradiation

目的分析α粒子辐射诱发永生化人支气管上皮细胞恶性转化过程中DNA甲基化谱的变化。方法分别提取α粒子诱发永生化人支气管上皮恶性转化细胞BERP35T4和对照细胞BEP2D的基因组DNA，用非甲基化敏感酶MseI对基因组DNA进行酶切，然后在酶解后的片段两端连接上连接臂，再用甲基化敏感内切酶进行消化，最终消化产物进行PCR扩增和荧光标记，最后与甲基化芯片进行杂交。杂交结果进行扫描，并对芯片图像进行分析，对芯片上的数据进行归一化处理，最后以差异倍数为1．5的标准来确定差异表达基因。结果α粒子辐射诱发永生化人支气管上皮细胞恶性转化后，有16个基因发生了甲基化的改变，其中，甲基化上调基因有9个，下调基因7个。鞘氨酸激酶SKIP，蛋白质磷酸酶PPP3CC，蛋白激酶MAP2K6，杀伤细胞免疫球蛋白受体KIR2DLl、KIR2DL4、KIR3DPI，锌指蛋白ZNF493、ZNFl00，转录因子NKX2—5、TFAP2D、DR1，钾离子通道KCNJl6，肉瘤抗原CCDCl8，以及甘油甲酸酯结合蛋白FNBPlL、同源异形蛋白IRX4、HSF蛋白片段EPB41L3、TCPl0蛋白等都发生了甲基化改变。结论证实了电离辐射能够通过改变细胞的表观遗传修饰而在肿瘤发生中发挥一定的作用。

Objective To identify the changes of DNA methylation profile in the process of malignant transformation of BEP2D cell induced by α particles. Methods The genomic DNAs were isolated from the malignant transformation BERP35T4 cells and immortalized human bronchial epithelial cell line BEP2D. Genomie DNAs were digested by MseI and ligated of PCR linkers. Methylated DNAs were digested by BstUI and amplified by PCR. The methylated DNA probes were prepared by labeling with Cy3 and Cy5 fluorescence dyes individually and hybridized to the methylation CpG-Island microarray. The hybridization results were scanned and analyzed. Intensity values were quality controlled and normalized. The normalized data were used to identify the differentially expressed genes based on a 1.5 fold difference of the expression level. Results There were 16 genes which showed changes of methylation level in malignant transformation BERP35T4 eells, 9 of them were hypermethylation and 7 were hypomethylation. These genes were including the SKIP gene, PPP3CC gene, MAP2K6 gene, KIR2DL1 gene, KIR2DL4 gene, KIR3DP1 gene, ZNF493 gene, ZNFIO0 gene, NKX2-5 gene, TFAP2D gene, DR1 gene, KCNJ16 gene, CCDC18 gene, FNBP1 L gene, IRX4 gene, EPB41L3 gene, TCP10 gene and so on. Conclusions The DNA methylation might have effects on ionizing radiation drived tumorigenesis.