Ccne1 过表达导致肝细胞染色体不稳定性和小鼠肝脏肿瘤的发生。
Ccne1 Overexpression Causes Chromosome Instability in Liver Cells and Liver Tumor Development in Mice.
机构信息
Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota.
Department of Pediatric and Adolescent Medicine, Mayo Clinic, Rochester, Minnesota; Department of Pediatrics, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
出版信息
Gastroenterology. 2019 Jul;157(1):210-226.e12. doi: 10.1053/j.gastro.2019.03.016. Epub 2019 Mar 13.
BACKGROUND & AIMS: The CCNE1 locus, which encodes cyclin E1, is amplified in many types of cancer cells and is activated in hepatocellular carcinomas (HCCs) from patients infected with hepatitis B virus or adeno-associated virus type 2, due to integration of the virus nearby. We investigated cell-cycle and oncogenic effects of cyclin E1 overexpression in tissues of mice.
METHODS
We generated mice with doxycycline-inducible expression of Ccne1 (Ccne1 mice) and activated overexpression of cyclin E1 from age 3 weeks onward. At 14 months of age, livers were collected from mice that overexpress cyclin E1 and nontransgenic mice (controls) and analyzed for tumor burden and by histology. Mouse embryonic fibroblasts (MEFs) and hepatocytes from Ccne1 and control mice were analyzed to determine the extent to which cyclin E1 overexpression perturbs S-phase entry, DNA replication, and numbers and structures of chromosomes. Tissues from 4-month-old Ccne1 and control mice (at that age were free of tumors) were analyzed for chromosome alterations, to investigate the mechanisms by which cyclin E1 predisposes hepatocytes to transformation.
RESULTS
Ccne1 mice developed more hepatocellular adenomas and HCCs than control mice. Tumors developed only in livers of Ccne1 mice, despite high levels of cyclin E1 in other tissues. Ccne1 MEFs had defects that promoted chromosome missegregation and aneuploidy, including incomplete replication of DNA, centrosome amplification, and formation of nonperpendicular mitotic spindles. Whereas Ccne1 mice accumulated near-diploid aneuploid cells in multiple tissues and organs, polyploidization was observed only in hepatocytes, with losses and gains of whole chromosomes, DNA damage, and oxidative stress.
CONCLUSIONS
Livers, but not other tissues of mice with inducible overexpression of cyclin E1, develop tumors. More hepatocytes from the cyclin E1-overexpressing mice were polyploid than from control mice, and had losses or gains of whole chromosomes, DNA damage, and oxidative stress; all of these have been observed in human HCC cells. The increased risk of HCC in patients with hepatitis B virus or adeno-associated virus type 2 infection might involve activation of cyclin E1 and its effects on chromosomes and genomes of liver cells.
背景与目的
CCNE1 基因座编码细胞周期蛋白 E1，在许多类型的癌细胞中扩增，并在乙型肝炎病毒或腺相关病毒 2 感染的肝细胞癌（HCC）中激活，这是由于病毒附近的整合。我们研究了细胞周期蛋白 E1 过表达在小鼠组织中的致癌作用。
方法
我们生成了可诱导表达 Ccne1 的小鼠（Ccne1 小鼠），并从 3 周龄开始激活过表达细胞周期蛋白 E1。在 14 个月大时，从过表达细胞周期蛋白 E1的小鼠和非转基因小鼠（对照）中收集肝脏，并进行肿瘤负担和组织学分析。分析 Ccne1 和对照小鼠的小鼠胚胎成纤维细胞（MEF）和肝细胞，以确定细胞周期蛋白 E1 过表达在多大程度上扰乱 S 期进入、DNA 复制以及染色体的数量和结构。分析 4 个月大的 Ccne1 和对照小鼠（此时没有肿瘤）的组织，以研究细胞周期蛋白 E1 使肝细胞易于转化的机制。
结果
Ccne1 小鼠比对照小鼠更容易发生肝细胞腺瘤和 HCC。肿瘤仅在 Ccne1 小鼠的肝脏中发生，尽管其他组织中存在高水平的细胞周期蛋白 E1。Ccne1 MEF 存在促进染色体错误分离和非整倍体的缺陷，包括 DNA 不完全复制、中心体扩增和形成非垂直的有丝分裂纺锤体。虽然 Ccne1 小鼠在多个组织和器官中积累了近二倍体非整倍体细胞，但仅在肝细胞中观察到多倍体化，存在整个染色体的缺失和增益、DNA 损伤和氧化应激。
结论
可诱导过表达细胞周期蛋白 E1 的小鼠的肝脏而不是其他组织会发生肿瘤。来自过表达细胞周期蛋白 E1 的小鼠的肝细胞比来自对照小鼠的多倍体化程度更高，并且存在整个染色体的缺失或增益、DNA 损伤和氧化应激；这些都在人 HCC 细胞中观察到。乙型肝炎病毒或腺相关病毒 2 感染患者患 HCC 的风险增加可能涉及细胞周期蛋白 E1 的激活及其对肝细胞染色体和基因组的影响。
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