Department of Clinical Genetics, Lund University, University and Regional Laboratories, Lund, Sweden.
Exp Cell Res. 2010 Dec 10;316(20):3379-86. doi: 10.1016/j.yexcr.2010.07.010. Epub 2010 Jul 17.
Established tumour cell lines are ubiquitous tools in research, but their representativity is often debated. One possible caveat is that many cell lines are derived from cells with genomic instability, potentially leading to genotype changes in vitro. We applied SNP-array analysis to an established tumour cell line (WiT49). Even though WiT49 exhibited chromosome segregation errors in 30% of cell divisions, only a single chromosome segment exhibited a shift in copy number after 20 population doublings in culture. In contrast, sub-populations derived from single cells expanded for an equal number of population doublings showed on average 5.8 and 8.9 altered segments compared to the original culture and to each other, respectively. Most copy number variants differentiating these single cell clones corresponded to pre-existing variations in the original culture. Furthermore, no sub-clonal variation was detected in any of the populations derived from single cells. This indicates that genetic bottlenecks resulting from population reduction poses a higher threat to genetic representativity than prolonged culture per se, even in cell lines with a high rate of genomic instability. Genetic bottlenecks should therefore be considered a potential caveat in all studies involving sub-cloning, transfection and other conditions leading to a temporary reduction in cell number.
已建立的肿瘤细胞系是研究中无处不在的工具，但它们的代表性常常存在争议。一个可能的问题是，许多细胞系源自具有基因组不稳定性的细胞，这可能导致体外基因型发生变化。我们应用 SNP 芯片分析对一个已建立的肿瘤细胞系（WiT49）进行了研究。尽管 WiT49 在 30%的细胞分裂中表现出染色体分离错误，但在培养 20 个倍增后，只有一个染色体片段的拷贝数发生了变化。相比之下，从单个细胞中扩增相同数量的倍增的亚群与原始培养物相比，平均分别有 5.8 个和 8.9 个发生改变的片段，与彼此相比。这些单细胞克隆之间区分的大多数拷贝数变异与原始培养物中预先存在的变异相对应。此外，在任何源自单个细胞的群体中都未检测到亚克隆变异。这表明，与长期培养本身相比，即使在基因组不稳定性较高的细胞系中，由于群体减少导致的遗传瓶颈对遗传代表性构成的威胁更大。因此，在涉及亚克隆、转染和其他导致细胞数量暂时减少的条件的所有研究中，都应考虑遗传瓶颈是一个潜在的问题。
