The role of DNA methylation in expression of the p19/p16 locus in human bladder cancer cell lines.
The role of DNA methylation in expression of the p19/p16 locus in human bladder cancer cell lines.
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发表时间：
1998-03
期刊：
影响因子：
11.2
通讯作者：
M. Gonzalgo;Toshiro Hayashida;C. Bender;M. Pao;Y. Tsai;F. Gonzales;Hung D. Nguyen;Tudung T. Nguyen;P. Jones
中科院分区：
文献类型：
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作者：
M. Gonzalgo;Toshiro Hayashida;C. Bender;M. Pao;Y. Tsai;F. Gonzales;Hung D. Nguyen;Tudung T. Nguyen;P. Jones
抑癌基因调控区CpG位点的甲基化可能是其可遗传但可逆的转录失活的重要机制。甲基化的这些变化可能损害细胞周期调控基因的正确表达和/或功能，并赋予受影响细胞选择性生长优势。使用基因组亚硫酸氢盐测序对膀胱癌细胞系的一系列亚克隆进行详细的甲基化分析，其中高甲基化的p16基因已通过5-氮杂-2'-脱氧胞苷的瞬时处理而被重新激活。人膀胱癌细胞中p16基因启动子中CpG岛的甲基化并不能阻止由p19启动子上游20 kb启动的转录物的形成，但确实阻止了p16转录物的表达。此外，我们发现，反应性克隆，表达p16在不同的水平包含异质性甲基化模式，这表明p16的表达，甚至可以发生在一个相对高度甲基化的编码区的存在下。我们还提出了第一个功能性证据，即只有少量的CpG位点的甲基化可以显着下调p16启动子活性，从而为该肿瘤抑制基因通过DNA甲基化进行性失活的模型提供支持。
Methylation of CpG sites in the control regions of tumor suppressor genes may be an important mechanism for their heritable, yet reversible, transcriptional inactivation. These changes in methylation may impair the proper expression and/or function of cell cycle regulatory genes and confer a selective growth advantage to affected cells. Detailed methylation analysis using genomic bisulfite sequencing was performed on a series of subclones of a bladder cancer cell line in which a hypermethylated p16 gene had been reactivated by transient treatment with 5-aza-2'-deoxycytidine. Methylation of the CpG island in the promoter of the p16 gene in human bladder cancer cells did not stop the formation of a transcript initiated 20 kb upstream by the p19 promoter but did prevent the expression of a p16 transcript. Furthermore, we show that reactivant clones that expressed p16 at varying levels contained heterogeneous methylation patterns, suggesting that p16 expression can occur even in the presence of a relatively heavily methylated coding region. We also present the first functional evidence that methylation of only a small number of CpG sites can significantly down-regulate p16 promoter activity, thus providing support for the model of progressive inactivation of this tumor suppressor gene by DNA methylation.