Epigenetic regulation of vitamin D 24-hydroxylase/CYP24A1 in human prostate cancer.
Epigenetic regulation of vitamin D 24-hydroxylase/CYP24A1 in human prostate cancer.
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DOI：
10.1158/0008-5472.can-10-0617
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发表时间：
2010-07-15
期刊：
影响因子：
11.2
通讯作者：
Trump DL
中科院分区：
文献类型：
--
作者：
Luo W;Karpf AR;Deeb KK;Muindi JR;Morrison CD;Johnson CS;Trump DL
骨化三醇是一种具有抗肿瘤特性的钙稳态调节剂，它是由CYP24A1基因的产物降解的，该基因在人类前列腺癌中下调的机制未知。我们发现，在前列腺癌细胞系中，CYP24A1的表达与启动子DNA甲基化呈负相关。用DNA甲基转移酶抑制剂5-氮杂-2‘-脱氧胞苷(DAC)处理前列腺癌细胞可激活细胞色素P24A1的表达。在体外，CYP24A1启动子的甲基化抑制了其启动子的活性。此外，曲古抑菌素A(TSA)抑制组蛋白脱乙酰酶可增强前列腺癌细胞中CYP24A1的表达。芯片定量聚合酶链式反应显示，特异性的组蛋白修饰与CYP24A1启动子区域相关。TSA处理增加了H3K9ac和H3K4me2，同时降低了CYP24A1启动子上的H3K9me2。ChIP-qPCR分析表明，DAC和TSA处理增加了VDR对CYP24A1启动子的募集。对配对的人前列腺样本的RT-PCR分析表明，与邻近的组织学良性病变相比，CYP24A1在前列腺恶性病变中的表达下调。亚硫酸氢盐焦磷酸测序显示，与良性病变相比，恶性病变中的CYP24A1基因高甲基化。我们的发现表明，在人类前列腺癌细胞中，抑制CYP24A1基因的表达部分是通过启动子DNA甲基化和抑制性组蛋白修饰来实现的。
Calcitriol, a regulator of calcium homeostasis with antitumor properties, is degraded by the product of the CYP24A1 gene which is downregulated in human prostate cancer by unknown mechanisms. We found that CYP24A1 expression is inversely correlated with promoter DNA methylation in prostate cancer cell lines. Treatment with the DNA methyltransferase inhibitor 5-aza-2′-deoxycytidine (DAC) activates CYP24A1 expression in prostate cancer cells. In vitro methylation of the CYP24A1 promoter represses its promoter activity. Furthermore, inhibition of histone deacetylases by trichostatin A (TSA) enhances the expression of CYP24A1 in prostate cancer cells. ChIP-qPCR reveals that specific histone modifications are associated with the CYP24A1 promoter region. Treatment with TSA increases H3K9ac and H3K4me2 and simultaneously decreases H3K9me2 at the CYP24A1 promoter. ChIP-qPCR assay reveals that treatment with DAC and TSA increases the recruitment of VDR to the CYP24A1 promoter. RT-PCR analysis of paired human prostate samples reveals that CYP24A1 expression is down-regulated in prostate malignant lesions compared to adjacent histologically benign lesions. Bisulfite pyrosequencing shows that CYP24A1 gene is hypermethylated in malignant lesions compared to matched benign lesions. Our findings indicate that repression of CYP24A1 gene expression in human prostate cancer cells is mediated in part by promoter DNA methylation and repressive histone modifications.