Epigenetics of gene expression in human hepatoma cells: expression profiling the response to inhibition of DNA methylation and histone deacetylation.
Epigenetics of gene expression in human hepatoma cells: expression profiling the response to inhibition of DNA methylation and histone deacetylation.
复制标题
DOI：
10.1186/1471-2164-7-181
复制
发表时间：
2006-07-19
期刊：
影响因子：
4.4
通讯作者：
Edenberg, Howard J
中科院分区：
文献类型：
--
作者：
Dannenberg, Luke O;Edenberg, Howard J
DNA甲基化和组蛋白去乙酰化是真核生物基因调控的重要表观遗传机制。我们推测人肝癌细胞系HepG 2中的许多基因受到DNA甲基化和组蛋白去乙酰化的调控。用5-氮杂-2 '-脱氧胞苷（5-aza-dC）抑制DNA甲基化和/或用曲古抑菌素A（TSA）抑制组蛋白脱乙酰化的治疗应使我们能够鉴定肝癌细胞中表观遗传学调控的基因。5-aza-dC对HepG 2细胞中的基因表达的影响比TSA大得多，如使用AffyphoiK ® HG-U133 Plus 2.0微阵列所测量的。1504个探针组的表达受5-aza-dC影响（p < 0.01），535个探针组受TSA影响，1929个探针组受5-aza-dC和TSA的组合影响。5-aza-dC处理开启了211个探针组的表达，这些探针组在其不存在时不能检测到表达。受DNA甲基化调控的印迹基因（如H19和NNAT）的表达在5-aza-dC的作用下被打开或大大增加。参与肝脏过程的基因，如异生物质代谢（CYP 3A 4、CYP 3A 5和CYP 3A 7）和类固醇生物合成（CYP 17 A1和CYP 19 A1），以及编码CCAAT元件结合蛋白（C/EBPα、C/EBPβ和C/EBPγ）的基因受到5-aza-dC或其组合的影响。许多属于这些组的基因也在发育中的胎儿肝脏和成人肝脏中表达。定量实时RT-PCR检测证实了微阵列分析中所见的选定基因表达变化。表观遗传学在调节参与HepG 2细胞中的重要肝脏过程（例如异生物质代谢和类固醇生物合成）的几个基因的表达中起作用。许多基因的表达通常是沉默的，在这些肝癌细胞被重新表达的5-aza-dC处理。DNA甲基化可能是肝脏发育过程中限制胎儿基因表达和关闭肝癌细胞表达的一个因素。
DNA methylation and histone deacetylation are epigenetic mechanisms that play major roles in eukaryotic gene regulation. We hypothesize that many genes in the human hepatoma cell line HepG2 are regulated by DNA methylation and histone deacetylation. Treatment with 5-aza-2'-deoxycytidine (5-aza-dC) to inhibit DNA methylation with and/or Trichostatin A (TSA) to inhibit histone deacetylation should allow us to identify genes that are regulated epigenetically in hepatoma cells. 5-aza-dC had a much larger effect on gene expression in HepG2 cells than did TSA, as measured using Affymetrix® HG-U133 Plus 2.0 microarrays. The expression of 1504 probe sets was affected by 5-aza-dC (at p < 0.01), 535 probe sets by TSA, and 1929 probe sets by the combination of 5-aza-dC and TSA. 5-aza-dC treatment turned on the expression of 211 probe sets that were not detectably expressed in its absence. Expression of imprinted genes regulated by DNA methylation, such as H19 and NNAT, was turned on or greatly increased in response to 5-aza-dC. Genes involved in liver processes such as xenobiotic metabolism (CYP3A4, CYP3A5, and CYP3A7) and steroid biosynthesis (CYP17A1 and CYP19A1), and genes encoding CCAAT element-binding proteins (C/EBPα, C/EBPβ, and C/EBPγ) were affected by 5-aza-dC or the combination. Many of the genes that fall within these groups are also expressed in the developing fetal liver and adult liver. Quantitative real-time RT-PCR assays confirmed selected gene expression changes seen in microarray analyses. Epigenetics play a role in regulating the expression of several genes involved in essential liver processes such as xenobiotic metabolism and steroid biosynthesis in HepG2 cells. Many genes whose expression is normally silenced in these hepatoma cells were re-expressed by 5-aza-dC treatment. DNA methylation may be a factor in restricting the expression of fetal genes during liver development and in shutting down expression in hepatoma cells.