The potential for human disease treatment using human pluripotent stem cells, including embryonic stem cells and induced pluripotent stem cells (iPSCs), also carries the risk of added genomic instability. Genomic instability is most often linked to DNA repair deficiencies, which indicates that screening/characterization of possible repair deficiencies in pluripotent human stem cells should be a necessary step prior to their clinical and research use. In this study, a comparison of DNA repair pathways in pluripotent cells, as compared to those in non-pluripotent cells, demonstrated that DNA repair capacities of pluripotent cell lines were more heterogeneous than those of differentiated lines examined and were generally greater. Although pluripotent cells had high DNA repair capacities for nucleotide excision repair, we show that ultraviolet radiation at low fluxes induced an apoptotic response in these cells, while differentiated cells lacked response to this stimulus, and note that pluripotent cells had a similar apoptotic response to alkylating agent damage. This sensitivity of pluripotent cells to damage is notable since viable pluripotent cells exhibit less ultraviolet light-induced DNA damage than do differentiated cells that receive the same flux. In addition, the importance of screening pluripotent cells for DNA repair defects was highlighted by an iPSC line that demonstrated a normal spectral karyotype, but showed both microsatellite instability and reduced DNA repair capacities in three out of four DNA repair pathways examined. Together, these results demonstrate a need to evaluate DNA repair capacities in pluripotent cell lines, in order to characterize their genomic stability, prior to their pre-clinical and clinical use.
Brimble SN, Zeng X, Weiler DA, Luo Y, Liu Y, et al. (2004) Karyotypic stability, genotyping, differentiation, feeder-free maintenance, and gene expression sampling in three human embryonic stem cell lines derived prior to August 9, 2001. Stem Cells Dev 13: 585–597.
Aladjem MI, Spike BT, Rodewald LW, Hope TJ, Klemm M, et al. (1998) ES cells do not activate p53-dependent stress responses and undergo p53-independent apoptosis in response to DNA damage. Curr Biol 8: 145–155.
Neganova I, Vilella F, Atkinson SP, Lloret M, Passos JF, et al. (2011) An important role for CDK2 in G1 to S checkpoint activation and DNA damage response in human embryonic stem cells. Stem Cells 29: 651–659.
Banuelos CA, Banath JP, Macphail SH, Zhao J, Eaves CA, et al. (2008) Mouse but not human embryonic stem cells are deficient in rejoining of ionizing radiation-induced DNA double-strand breaks. DNA Repair (Amst) 7(9): 1471–1483.
Wang X, Lin G, Martins-Taylor K, Zeng H, Xu RH (2009) Inhibition of caspase-mediated anoikis is critical for basic fibroblast growth factor-sustained culture of human pluripotent stem cells. J Biol Chem 284: 34054–34064.
Secretan MB, Scuric Z, Oshima J, Bishop AJ, Howlett NG, et al. (2004) Effect of Ku86 and DNA-PKcs deficiency on non-homologous end-joining and homologous recombination using a transient transfection assay. Mutat Res 554: 351–364.
Bates SE, Zhou NY, Federico LE, Xia L, O'Connor TR (2005) Repair of cyclobutane pyrimidine dimers or dimethylsulfate damage in DNA is identical in normal or telomerase-immortalized human skin fibroblasts. Nucleic Acids Res 33: 2475–2485.
Yarosh DB, Pena AV, Nay SL, Canning MT, Brown DA (2005) Calcineurin inhibitors decrease DNA repair and apoptosis in human keratinocytes following ultraviolet B irradiation. J Invest Dermatol 125: 1020–1025.
Boland CR, Thibodeau SN, Hamilton SR, Sidransky D, Eshleman JR, et al. (1998) A National Cancer Institute Workshop on Microsatellite Instability for cancer detection and familial predisposition: development of international criteria for the determination of microsatellite instability in colorectal cancer. Cancer Res 58: 5248–5257.
Nystrom-Lahti M, Sistonen P, Mecklin JP, Pylkkanen L, Aaltonen LA, et al. (1994) Close linkage to chromosome 3p and conservation of ancestral founding haplotype in hereditary nonpolyposis colorectal cancer families. Proc Natl Acad Sci U S A 91: 6054–6058.
Zhou NY, Bates SE, Bouziane M, Stary A, Sarasin A, et al. (2003) Efficient repair of cyclobutane pyrimidine dimers at mutational hot spots is restored in complemented Xeroderma pigmentosum group C and trichothiodystrophy/xeroderma pigmentosum group D cells. J Mol Biol 332: 337–351.
Mollamohammadi S, Taei A, Pakzad M, Totonchi M, Seifinejad A, et al. (2009) A simple and efficient cryopreservation method for feeder-free dissociated human induced pluripotent stem cells and human embryonic stem cells. Hum Reprod 24: 2468–2476.
Venema J, Bartosova Z, Natarajan AT, van Zeeland AA, Mullenders LH (1992) Transcription affects the rate but not the extent of repair of cyclobutane pyrimidine dimers in the human adenosine deaminase gene. J Biol Chem 267: 8852–8856.
Masutani C, Araki M, Yamada A, Kusumoto R, Nogimori T, et al. (1999) Xeroderma pigmentosum variant (XP-V) correcting protein from HeLa cells has a thymine dimer bypass DNA polymerase activity. Embo J 18: 3491–3501.
Raha M, Wang G, Seidman MM, Glazer PM (1996) Mutagenesis by third-strand-directed psoralen adducts in repair-deficient human cells: high frequency and altered spectrum in a xeroderma pigmentosum variant. Proc Natl Acad Sci U S A 93: 2941–2946.
Plaia TW, Josephson R, Liu Y, Zeng X, Ording C, et al. (2006) Characterization of a new NIH-registered variant human embryonic stem cell line, BG01V: a tool for human embryonic stem cell research. Stem Cells 24: 531–546.
Zeng X, Chen J, Liu Y, Luo Y, Schulz TC, et al. (2004) BG01V: a variant human embryonic stem cell line which exhibits rapid growth after passaging and reliable dopaminergic differentiation. Restor Neurol Neurosci 22: 421–428.
Feng Q, Lu SJ, Klimanskaya I, Gomes I, Kim D, et al. (2010) Hemangioblastic derivatives from human induced pluripotent stem cells exhibit limited expansion and early senescence. Stem Cells 28: 704–712.
Fan J, Wilson PF, Wong HK, Urbin SS, Thompson LH, et al. (2007) XRCC1 down-regulation in human cells leads to DNA-damaging agent hypersensitivity, elevated sister chromatid exchange, and reduced survival of BRCA2 mutant cells. Environ Mol Mutagen 48: 491–500.