Methods of Reprogramming to Induced Pluripotent Stem Cell Associated with Chromosomal Integrity and Delineation of a Chromosome 5q Candidate Region for Growth Advantage

Induced pluripotent stem cells (iPSCs) have brought great promises for disease modeling and cell-based therapies. One concern related to the use of reprogrammed somatic cells is the loss of genomic integrity and chromosome stability, a hallmark for cancer and many other human disorders. We investigated 16 human iPSC lines reprogrammed by nonintegrative Sendai virus (SeV) and another 16 iPSC lines generated by integrative lentivirus for genetic changes. At early passages we detected cytogenetic rearrangements in 44% (7/16) of iPSC lines generated by lentiviral integration whereas the corresponding figure was 6% (1/16) using SeV-based delivery. The rearrangements were numerical and/or structural with chromosomes 5 and 12 as the most frequently involved chromosomes. Three iPSC lines with chromosome 5 aberrations were derived from one and the same donor. We present in this study the aberrant karyotypes including a duplication of chromosome 5q13q33 that restricts a candidate region for growth advantage. Our results suggest that the use of integrative lentivirus confers a higher risk for cytogenetic abnormalities at early passages when compared to SeV-based reprogramming. In combination, our findings expand the knowledge on acquired cytogenetic aberrations in iPSC after reprogramming and during culture.