Ectopically hTERT expressing adult human mesenchymal stem cells are less radiosensitive than their telomerase negative counterpart.
During the past several years increasing evidence indicating that the proliferation capacity of mammalian cells is highly radiosensitive, regardless of the species and the tissue of origin of the cells, has accumulated. It has also been shown that normal bone marrow cells of mice have a similar radiosensitivity to other mammalian cells so far tested. In this study, we investigated the genetic effects of ionizing radiation (2.5-15 Gy) on normal human mesenchymal stem cells and their telomerised counterpart hMSC-telo1. We evaluated overall genomic integrity, DNA damage/repair by applying a fluorescence-detected alkaline DNA unwinding assay together with Western blot analyses for phosphorylated H2AX and Q-FISH was applied for investigation of telomeric damage. Our results indicate that hMSC and TERT-immortalized hMSCs can cope with relatively high doses of gamma-rays and that overall DNA repair is similar in the two cell lines. The telomeres were extensively destroyed after irradiation in both cell types suggesting that telomere caps are especially sensitive to radiation. The TERT-immortalized hMSCs showed higher stability at telomeric regions than primary hMSCs indicating that cells with long telomeres and high telomerase activity have the advantage of re-establishing the telomeric caps.
Serakinci
Nedime
N
Department of Human Genetics, University of Aarhus, Aarhus, Denmark. nserakinci@health.sdu.dk
Christensen
Rikke
R
Graakjaer
Jesper
J
Cairney
Claire J
CJ
Keith
W Nicol
WN
Alsner
Jan
J
Saretzki
Gabriele
G
Kolvraa
Steen
S
D053687:Adult Stem Cells / Q000201:enzymology / Q000378:metabolism* / Q000528:radiation effects; D000375:Aging / Q000378:metabolism; D015415:Biomarkers / Q000032:analysis; D049109:Cell Proliferation; D002470:Cell Survival; D002478:Cells, Cultured; D002875:Chromosomes / Q000235:genetics / Q000378:metabolism / Q000528:radiation effects; D019941:Cyclin-Dependent Kinase Inhibitor p16 / Q000378:metabolism; D004249:DNA Damage; D006657:Histones / Q000378:metabolism; D006801:Humans; D020287:In Situ Nick-End Labeling; D059630:Mesenchymal Stem Cells / Q000201:enzymology / Q000378:metabolism* / Q000528:radiation effects; D008954:Models, Biological; D010766:Phosphorylation; D019098:Telomerase / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D016615:Telomere / Q000502:physiology / Q000528:radiation effects; D014161:Transduction, Genetic; D025803:Tumor Suppressor Protein p14ARF / Q000378:metabolism; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism; D001616:beta-Galactosidase / Q000502:physiology
D015415:Biomarkers; D019941:Cyclin-Dependent Kinase Inhibitor p16; C468783:H2AX protein, human; D006657:Histones; D025803:Tumor Suppressor Protein p14ARF; D016159:Tumor Suppressor Protein p53; C509186:TERT protein, human; D019098:Telomerase; D001616:beta-Galactosidase