title: Human embryonic stem cells may display higher resistance to genotoxic stress as compared to primary explanted somatic cells.
abstract: The use of human embryonic stem (hES) cells in genotoxicity screening can potentially overcome the deficiencies associated with using immortalized cell lines, primary explanted somatic cells, and live animal models. Hence this study sought to compare the responses of hES cells and primary explanted somatic cells (IMR-90 cells, human fetal lung fibroblasts) to genotoxic stress, to evaluate whether hES cells can accurately reflect the normal physiology of human somatic cells. The effects of mitomycin C (MMC) on the chromosomal stability of hESC and IMR-90 was assayed and compared by fluorescence in situ hybridization (FISH) with telomere-specific peptide nucleic acid and multicolor (m) FISH techniques. The results showed that, the percentage of aberrant cells increased from 6% in the untreated control to 57.5% at the higher dose of 0.06 microg/ml MMC (9.6-fold increase) group in the case of IMR-90 cells, whereas hES cells displayed a corresponding increase from 6% to 28% (4.6-fold increase). Telomere FISH ascertained that the main types of damage induced by MMC are chromosomal breaks and the loss of telomeric signals. No fusions were observed in all samples analyzed. This was further confirmed by mFISH, which showed that fusions and translocations were not the type of aberration induced by MMC, with no such aberrations being observed in all samples analyzed. Hence, hES cells of the H1 line are apparently more resistant to MMC-induced DNA damage, as compared to the IMR-90 cells. These results highlight possible intrinsic differences in response to damaging agents between hES cells and normal somatic cells.
authors.affiliation: Stem Cell Program, Faculty of Dentistry, National University of Singapore, 119074 Singapore.
authors.forename: Kumar Jayaseelan
authors.initials: KJ
authors.lastname: Vinoth
authors.forename: Boon Chin
authors.initials: BC
authors.lastname: Heng
authors.forename: Anuradha
authors.initials: A
authors.lastname: Poonepalli
authors.forename: Birendranath
authors.initials: B
authors.lastname: Banerjee
authors.forename: Lakshmidevi
authors.initials: L
authors.lastname: Balakrishnan
authors.forename: Kai
authors.initials: K
authors.lastname: Lu
authors.forename: M Prakash
authors.initials: MP
authors.lastname: Hande
authors.forename: Tong
authors.initials: T
authors.lastname: Cao
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D019457:Chromosome Breakage / Q000187:drug effects; D004249:DNA Damage / Q000187:drug effects; D004351:Drug Resistance / Q000187:drug effects; D053595:Embryonic Stem Cells / Q000378:metabolism*; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007621:Karyotyping; D008677:Metaphase / Q000187:drug effects; D051379:Mice; D016685:Mitomycin / Q000494:pharmacology; D020135:Peptide Nucleic Acids / Q000378:metabolism; D016615:Telomere / Q000378:metabolism
chemical_list: D020135:Peptide Nucleic Acids; D016685:Mitomycin