Methylation profiling of CpG islands in human breast cancer cells
Methylation profiling of CpG islands in human breast cancer cells
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DOI：
10.1093/hmg/8.3.459
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发表时间：
1999-03-01
影响因子：
3.5
通讯作者：
Laux, DE
中科院分区：
文献类型：
--
作者：
Huang, THM;Perry, MR;Laux, DE
已知CpG岛高甲基化与癌症中的基因沉默有关。这种表观遗传事件通常被认为是肿瘤细胞中DNA甲基转移酶（DNA- mtase）活性异常引起的随机过程。CPG岛甲基化的特定模式可能是由于相关肿瘤抑制基因沉默导致细胞克隆选择具有生长优势。另外，甲基化模式可能由其他尚未确定的因素决定。为了进一步探索潜在的机制，我们开发了一种新的基于阵列的方法，称为差异甲基化杂交（DMH），它允许在肿瘤细胞中进行全基因组高甲基化CpG岛的筛选。用DMH测定了一组乳腺癌细胞系中>276 CpG岛位点的甲基化状态。与正常对照相比，在这些细胞中有5%至14%的这些位点被广泛地高甲基化。通过Southern杂交对30个阳性位点的模式分析表明，CpG岛对超甲基化的易感性可能存在差异，正常对照中存在甲基化的位点比没有甲基化的位点更容易在这些癌细胞中重新甲基化，此外，这些细胞系表现出不同的内在甲基化CpG岛的能力，与甲基转移酶活性没有直接关系。我们的研究提供了证据，除了随机的DNA-MTase作用外，存在其他控制乳腺癌细胞异常甲基化的细胞因子。
CpG island hypermethylation is known to be associated with gene silencing in cancer. This epigenetic event is generally accepted as a stochastic process in tumor cells resulting from aberrant DNA methyltransferase (DNA-MTase) activities. Specific patterns of CPG island methylation could result from clonal selection of cells having growth advantages due to silencing of associated tumor suppressor genes. Alternatively, methylation patterns may be determined by other, as yet unidentified factors, To explore further the underlying mechanisms, we developed a novel array-based method, called differential methylation hybridization (DMH), which allows a genome-wide screening of hypermethylated CpG islands in tumor cells. DMH was used to determine the methylation status of >276 CpG island loci in a group of breast cancer cell lines. Between 5 and 14% of these loci were hypermethylated extensively in these cells relative to a normal control. Pattern analysis of 30 positive loci by Southern hybridization indicated that CpG islands might differ in their susceptibility to hypermethylation, Loci exhibiting preexisting methylation in normal controls were more susceptible to de novo methylation in these cancer cells than loci without this condition, In addition, these cell lines exhibited different intrinsic abilities to methylate CpG islands not directly associated with methyltransferase activities. Our study provides evidence that, aside from random DNA-MTase action, additional cellular factors exist that govern aberrant methylation in breast cancer cells.