兰州大学机构库 >生命科学学院
镉诱导抑癌基因启动子甲基化促HepG2细胞增殖研究
Alternative TitleStudy on cadmium-enhanced HepG2 cell proliferation via promoter hypermethylation of tumor suppressor genes
张兴杰
Thesis Advisor黄德军
2016-05-18
Degree Grantor兰州大学
Place of Conferral兰州
Degree Name硕士
Keyword 人肝癌细胞HepG2 抑癌基因 DNA甲基化 细胞增殖
Abstract很多研究表明DNA甲基化与Cd的致癌性密切相关。而Cd是否会通过提高抑癌基因启动子区甲基化的水平促进人肝癌细胞HepG2的增殖尚不得而知;若Cd确实可以通过改变部分抑癌基因启动子甲基化诱导HepG2细胞的增殖,发挥关键作用的基因和位点也尚待确定。 为了探讨上述问题,本研究以HepG2为研究材料,筛选出Cd促细胞增殖最为明显的浓度及时间,检测了癌细胞恶性增殖相关基因COX-2和Ki-67的表达和3个增殖相关基因的启动子甲基化水平;另检测了甲基化发生改变的两个基因RASSF1A和DAPK1以及三个重要的甲基转移酶DNMT1、DNMT3a和DNMT3b的表达水平;同时,设有Cd和甲基化抑制剂5-氮杂胞苷(5-AZA)联合处理组,用以研究DNA甲基化在Cd诱导HepG2细胞增殖中发挥的作用。 结果表明,低浓度Cd处理会促进细胞增殖,Cd与5-AZA处理后细胞增殖受到明显的抑制,表明DNA甲基化在Cd诱导的HepG2细胞增殖中发挥作用;检测到Cd可以促进抑癌基因RASSF1A和DAPK1基因启动子的甲基化;各浓度Cd均可以降低RASSF1A和DAPK1的表达,且5-AZA部分恢复DAPK1和RASSF1A的基因表达水平。而甲基化测序结果表明500 nM Cd处理促进了DAPK1和RASSF1A启动子的高甲基化,5-AZA处理则使得上述两个基因的启动子区甲基化水平得以恢复,而且,DAPK1检测区域内三个位点以及RASSF1A的一个位点可能在Cd诱导的HepG2细胞增殖中发挥关键作用。
Other AbstractMany studies showed DNA methylation have the intimate relationship with carcinogenicity of Cd. It is still unknown whether Cd can induce human hepatoma cells HepG2 proliferation or not, which need further study. To investigate the questions mentioned above, we selected HepG2 as experiment material, exposed these cells to different doses of Cd, and measured the cell viability; We detected the expression of genes related to cell proliferation including COX-2 and Ki-67, investigated the promoter methylation status of several tumor suppressor genes, and studied the expression of several genes including RASSF1A, DAPK1, and three DNA Methyl transferase (DNMTs). At the same time, the combined treatment groups by DNA methylation inhibitor 5-Azacytidine (5-AZA) and Cd were set up to investigate the function of DNA methylation in Cd-induced cell proliferation. The results showed low dose Cd treatment could enhance HepG2 cell proliferation. Cd enhanced RASSF1A and DAPK1 promoter methylation. Cd significantly suppressed RASSF1A and DAPK1 expression, 5-AZA partly recovered expression of these two genes. The result by BSP showed that 500 nM Cd led to hypermethylation of DAPK1 and RASSF1A promoter and 5-AZA recoveried methylation status. Moreover, three CpG sites of DAPK1 and one CpG site of RASSF1A may play key roles in Cd-induced HepG2 cell proliferation.
URL查看原文
Language中文
Document Type学位论文
Identifierhttps://ir.lzu.edu.cn/handle/262010/221334
Collection生命科学学院
Recommended Citation
GB/T 7714
张兴杰. 镉诱导抑癌基因启动子甲基化促HepG2细胞增殖研究[D]. 兰州. 兰州大学,2016.
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