永生化上皮细胞系及肺鳞癌细胞系基因组DNA拷贝数变异的比较研究

Comparative Studies between the Copy Number Variations in Genomic DNA of an Immortalized Epithelial Cell Line and the Lung Squamous Cell Carcinoma Cell Line

目的:通过分析比较支气管上皮永生化细胞系与肺鳞癌细胞系的拷贝数变异探讨肿瘤早期发展的分子机制。方法:用人类比较基因组杂交芯片(aCGH)分别测定支气管上皮细胞系Y-BE和肺鳞癌细胞系NCI-H2170的拷贝数,经数据校正,对拷贝数变异基因进行GO(Gene Ontology)富集分析。结果:永生化上皮细胞系早代Yp21仅出现了少量的DNA拷贝数变异,而在染色体20 q11～12区段Yp21细胞与HCI-H2170细胞出现了相似的拷贝数变异结果;永生化上皮细胞系晚代Yp113具有类神经细胞黏附基因的拷贝数增加现象;整体来看,从永生化上皮细胞早代到晚代,再与肿瘤细胞比较,DNA拷贝数变异频率不断升高,基因组稳定性逐渐下降结论:通过对永生化上皮细胞拷贝数变异的研究,成功建立了肺癌癌前模型的拷贝数变异谱,部分拷贝数变异可能代表了肿瘤发生发展早期的分子事件,预示了细胞的潜在恶性,这些发现可能为阐明肿瘤发生发展的分子机制提供了条件。

Objective： This study aims to explore the molecular mechanisms in the progression of early-stage tumors by comparing and analyzing the copy number variation （ CNV ） in an immortalized epithelial cell line and the lung squamous cell carcinoma cell line. Methods： Human genome array-comparative genomic hybridization was used to measure the CNVs of the immortalized cell line Y-BE and the lung squamous cell carcinoma cell line NC1-H2170. An analysis of the Gene .Ontology functional enrichment of the genes with abnormal copy numbers was conducted after data reconciliation. Results： Only a few variations occurred in the early passage of the Y-BE cell, Yp21. A large overlapping CNV region in 20 q 11-12 between the cell Yp21 and NCI-H2170 was found. The copy-num- ber gain of neural cadherin-like cell adhesion genes occurred in the late passage of the Y-BE cell, Yp 113. Compared with NCI-H2170, the CNV frequency of Yp113 increased, whereas the genome stability from the early passage Y-BE to the late passage one decreased. Conclusion： After studying CNVs in the immortalized epithelial cell line, the CNV spectrum of variation of the precancerous model for lung cancer was successfully built. Some of the CNVs represented an early molecular event of tumor progression, indicating the poten- tial malignancy of the cells. The findings of this study may give clues clarifying the molecular mechanisms of tumorigenesis and pro- gression.