Pluripotent Stem Cells and DNA Damage Response to Ionizing Radiations

Mujoo, Kalpana; Butler, E. Brian; Pandita, Raj K.; Hunt, Clayton R.; Pandita, Tej K.

doi:10.1667/rr14417.1

Cited by 11 publications

(6 citation statements)

References 112 publications

(125 reference statements)

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“…Similar results were obtained in human ES cells and hiPSCs when exposed to girradiation, resulting in capase-3 cleavage within four hours of treatment [10]. Interestingly, PSCs exhibit a response to DNA damage that is remarkably similar regardless of lineage, whereas the DNA damage response elicited by differentiated somatic cells is highly cell-type dependent [11]. Recent data also demonstrated that the degree of pluripotency contributes to the DNA damage response elicited by irradiation, with iPSCs exhibiting a greater response than neonatal stromal cells, both of which are more sensitive than adult stromal cells [12].…”

Section: Introductionsupporting

confidence: 73%

Quantification of Etoposide Hypersensitivity: A Sensitive, Functional Method for Assessing Pluripotent Stem Cell Quality

Secreto

Smith

et al. 2017

Stem Cells Translational Medicine

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Human induced pluripotent stem cells (hiPSC) hold great promise in diagnostic and therapeutic applications. However, translation of hiPSC technology depends upon a means of assessing hiPSC quality that is quantitative, high-throughput, and can decipher malignant teratocarcinoma clones from normal cell lines. These attributes are lacking in current approaches such as detection of cell surface makers, RNA profiling, and/or teratoma formation assays. The latter remains the gold standard for assessing clone quality in hiPSCs, but is expensive, time-consuming, and incompatible with high-throughput platforms. Herein, we describe a novel method for determining hiPSC quality that exploits pluripotent cells' documented hypersensitivity to the topoisomerase inhibitor etoposide (CAS No. 33419-42-0). Based on a study of 115 unique hiPSC clones, we established that a half maximal effective concentration (EC50) value of <300 nM following 24 hours of exposure to etoposide demonstrated a positive correlation with RNA profiles and colony morphology metrics associated with high quality hiPSC clones. Moreover, our etoposide sensitivity assay (ESA) detected differences associated with culture maintenance, and successfully distinguished malignant from normal pluripotent clones independent of cellular morphology. Overall, the ESA provides a simple, straightforward method to establish hiPSC quality in a quantitative and functional assay capable of being incorporated into a generalized method for establishing a quality control standard for all types of pluripotent stem cells. STEM CELLS TRANSLATIONAL MEDICINE 2017;6:1829-1839 SIGNIFICANCE STATEMENTA quantitative measure of human induced pluripotent stem cell (hiPSC) pluripotency has yet to be standardized, an issue that must be remedied if widespread translational application of this technology is to occur. Secreto et al. provide an innovative method for quantifying hiPSC pluripotency based upon exploiting the hypersensitivity pluripotent cells exhibit to the DNA damaging agent etoposide. Their etoposide sensitivity assay determines hiPSC suitability by quantifying the amount of etoposide required to kill the treated cells, and comparing that amount to a standard value known to be associated with high quality clones.

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Section: Introductionsupporting

confidence: 73%

Quantification of Etoposide Hypersensitivity: A Sensitive, Functional Method for Assessing Pluripotent Stem Cell Quality

Secreto

Smith

et al. 2017

Stem Cells Translational Medicine

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“…When DNA damage cannot be repaired, cells undergo senescence, apoptosis or differentiation. The specific response triggered by genotoxic stress largely depends on the stem cell type and their developmental context ( Mujoo et al, 2016 ).…”

Section: Differential Responses To Dna Damage Depending On Cellular C...mentioning

confidence: 99%

Regulation and coordination of the different DNA damage responses in Drosophila

Baonza

Tur-Gracia

Pérez-Aguilera

et al. 2022

Front. Cell Dev. Biol.

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Cells have evolved mechanisms that allow them to respond to DNA damage to preserve genomic integrity and maintain tissue homeostasis. These responses include the activation of the cell cycle checkpoints and the repair mechanisms or the induction of apoptosis that eventually will eliminate damaged cells. These “life” vs. “death” decisions differ depending on the cell type, stages of development, and the proliferation status of the cell. The apoptotic response after DNA damage is of special interest as defects in its induction could contribute to tumorigenesis or the resistance of cancer cells to therapeutic agents such as radiotherapy. Multiples studies have elucidated the molecular mechanisms that mediate the activation of the DNA damage response pathway (DDR) and specifically the role of p53. However, much less is known about how the different cellular responses such as cell proliferation control and apoptosis are coordinated to maintain tissue homeostasis. Another interesting question is how the differential apoptotic response to DNA damage is regulated in distinct cell types. The use of Drosophila melanogaster as a model organism has been fundamental to understand the molecular and cellular mechanisms triggered by genotoxic stress. Here, we review the current knowledge regarding the cellular responses to ionizing radiation as the cause of DNA damage with special attention to apoptosis in Drosophila: how these responses are regulated and coordinated in different cellular contexts and in different tissues. The existence of intrinsic mechanisms that might attenuate the apoptotic pathway in response to this sort of DNA damage may well be informative for the differences in the clinical responsiveness of tumor cells after radiation therapy.

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“…Yet, our knowledge of DNA damage and repair responses to radiation comes predominantly from somatic cell models. Although human stem cells have been studied for their DNA damage and repair responses to acute radiation exposures [ 22 – 24 ], very few studies have used prolonged irradiation [ 25 ]. Multipotent mesenchymal stem cells (MSCs) are a well-characterized type of stem cells [ 26 ], widely used in stem cell-based therapy of various diseases [ 26 ].…”

Section: Introductionmentioning

confidence: 99%

γH2AX, 53BP1 and Rad51 protein foci changes in mesenchymal stem cells during prolonged X-ray irradiation

et al. 2017

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At high exposure levels ionizing radiation is a carcinogen. Little is known about how human stem cells, which are known to contribute to tumorigenesis, respond to prolonged radiation exposures. We studied formation of DNA double strand breaks, accessed as γH2AX and 53BP1 foci, in human mesenchymal stem cells (MSCs) exposed to either acute (5400 mGy/h) or prolonged (270 mGy/h) X-irradiation. We show a linear γH2AX and 53BP1 dose response for acute exposures. In contrast, prolonged exposure resulted in a dose-response curve that had an initial linear portion followed by a plateau. Analysis of Rad51 foci, as a marker of homologous recombination, in cells exposed to prolonged irradiation revealed a threshold in a dose response. Using Ki67 as a marker of proliferating cells, we show no difference in the γH2AX distribution in proliferating vs. quiescent cells. However, Rad51 foci were found almost exclusively in proliferating cells. Concurrent increases in the fraction of S/G2 cells were detected in cells exposed to prolonged irradiation by scoring CENPF-positive cells. Our data suggest that prolonged exposure of MSCs to ionizing radiation leads to cell cycle redistribution and associated activation of homologous recombination. Also, proliferation status may significantly affect the biological outcome, since homologous repair is not activated in resting MSCs.

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Pluripotent Stem Cells and DNA Damage Response to Ionizing Radiations

Cited by 11 publications

References 112 publications

Quantification of Etoposide Hypersensitivity: A Sensitive, Functional Method for Assessing Pluripotent Stem Cell Quality

Quantification of Etoposide Hypersensitivity: A Sensitive, Functional Method for Assessing Pluripotent Stem Cell Quality

Regulation and coordination of the different DNA damage responses in Drosophila

γH2AX, 53BP1 and Rad51 protein foci changes in mesenchymal stem cells during prolonged X-ray irradiation

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