肝癌细胞系与正常细胞系中的组蛋白修饰差异分析

The Difference Analysis of Histone Modifications in Cancer Cell Line HepG2 and Normal Cell Line Hepatocyte

摘要: 肝癌是全世界癌症发病率和死亡率都非常高的恶性肿瘤，越来越多的研究发现表观修饰对癌症的发生有重要的影响。为了了解肝癌中组蛋白修饰发生了哪些变化，我们统计了肝癌细胞系HepG2和正常细胞系hepatocyte中的11种组蛋白修饰在启动子区域的组蛋白修饰分布模式，并分析了启动子区域组蛋白修饰和基因表达，以及组蛋白修饰之间的相关性。结果表明这11种组蛋白修饰在启动子区域主要有两种分布模式，癌症细胞系中的组蛋白修饰值普遍比正常细胞系中高；组蛋白修饰与基因表达的Spearman相关性分析表明，H3K9me3在两种细胞系中与基因表达呈相反的相关性，而且发现相关性分布与组蛋白修饰分布趋势一致。通过对两种细胞系高低表达基因上的组蛋白修饰分析，发现高表达基因中组蛋白修饰差异更显著。这些结果表明，分析组蛋白修饰的变化对肝癌的研究具有一定的意义。

Abstract: Liver cancer is a malignant tumor with high cancer morbidity and mortality in the world. More and more studies have found that the histone modifications (HMs) have an important impact on the occurrence of cancer. In order to understand the changes of HMs in liver cancer, we calculate the distribution patterns of eleven HMs in the promoter region for two kinds of cell lines, and analyze the correlation between HM and gene expression, and the correlation between HMs. The results show that there are two kinds of distribution patterns of HMs in promoter region, and the HMs values are generally higher in cancer cell line than in normal cell line. The results indicate that the Spearman correlation between H3K9me3 and gene expression is different in two kinds of cell lines, and the trends of distributions of HMs and correlation are consistent. By analyzing the HMs in highly and lowly expressed genes of two kinds of cell lines, it is found that the difference of HMs is remarkable in highly expressed genes. These results indicate that the analysis of changes for HMs is significant for the study of liver cancer.