Cancer Genomics, Ontario Institute for Cancer Research, Toronto, Ontario, Canada.
Stem Cells. 2012 Mar;30(3):435-40. doi: 10.1002/stem.1011.
Mutations in human induced pluripotent stem cells (iPSCs) pose a risk for their clinical use due to preferential reprogramming of mutated founder cell and selection of mutations during maintenance of iPSCs in cell culture. It is unknown, however, if mutations in iPSCs are due to stress associated with oncogene expression during reprogramming. We performed whole exome sequencing of human foreskin fibroblasts and their derived iPSCs at two different passages. We found that in vitro passaging contributed 7% to the iPSC coding point mutation load, and ultradeep amplicon sequencing revealed that 19% of the mutations preexist as rare mutations in the parental fibroblasts suggesting that the remaining 74% of the mutations were acquired during cellular reprogramming. Simulation suggests that the mutation intensity during reprogramming is ninefold higher than the background mutation rate in culture. Thus the factor induced reprogramming stress contributes to a significant proportion of the mutation load of iPSCs.
人类诱导多能干细胞（iPSC）中的突变会给其临床应用带来风险，这是由于突变起始细胞的优先重编程和 iPSC 在细胞培养过程中的维持过程中对突变的选择。然而，目前尚不清楚 iPSC 中的突变是否是由于重编程过程中与癌基因表达相关的应激引起的。我们对人包皮成纤维细胞及其衍生的 iPSC 在两个不同传代中进行了全外显子测序。我们发现，体外传代导致 iPSC 编码点突变负荷增加了 7%，而超深度扩增子测序显示，19%的突变在亲本成纤维细胞中作为罕见突变预先存在，这表明其余 74%的突变是在细胞重编程过程中获得的。模拟表明，重编程过程中的突变强度比培养中的背景突变率高九倍。因此，诱导重编程应激的因素导致 iPSC 突变负荷的很大一部分。
