Measurement of Radiation-Induced DNA Damage Using Gel Electrophoresis or Neutral Filter Elution Shows an Increased Frequency of DNA Strand Breaks after Exposure to pH 9.6

1989 ◽  
Vol 119 (3) ◽  
pp. 452 ◽  
Author(s):  
Maryann B. Flick ◽  
Raymond L. Warters ◽  
Linda S. Yasui ◽  
Robert E. Krisch
Keyword(s):  
Dna Damage ◽  
Gel Electrophoresis ◽  
Dna Strand Breaks ◽  
Strand Breaks ◽  
Radiation Induced ◽  
Dna Strand

KGF facilitates repair of radiation-induced DNA damage in alveolar epithelial cells

1997 ◽  
Vol 272 (6) ◽  
pp. L1174-L1180 ◽  
Author(s):  
M. Takeoka ◽  
W. F. Ward ◽  
H. Pollack ◽  
D. W. Kamp ◽  
R. J. Panos
Keyword(s):  
Dna Damage ◽  
Dna Repair ◽  
Epithelial Cells ◽  
Dna Polymerase ◽  
Dna Polymerases ◽  
Dna Strand Breaks ◽  
Strand Breaks ◽  
Alveolar Epithelial ◽  
Radiation Induced ◽  
Dna Strand

Administration of exogenous keratinocyte growth factor (KGF) prevents or attenuates several forms of oxidant-mediated lung injury. Because DNA damage in epithelial cells is a component of radiation pneumotoxicity, we determined whether KGF ameliorated DNA strand breaks in irradiated A549 cells. Cells were exposed to 137Cs gamma rays, and DNA damage was measured by alkaline unwinding and ethidium bromide fluorescence after a 30-min recovery period. Radiation induced a dose-dependent increase in DNA strand breaks. The percentage of double-stranded DNA after exposure to 30 Gy increased from 44.6 +/- 3.5% in untreated control cells to 61.6 +/- 5.0% in cells cultured with 100 ng/ml KGF for 24 h (P < 0.05). No reduction in DNA damage occurred when the cells were cultured with KGF but maintained at 0 degree C during and after irradiation. The sparing effect of KGF on radiation-induced DNA damage was blocked by aphidicolin, an inhibitor of DNA polymerases-alpha, -delta, and -epsilon and by butylphenyl dGTP, which blocks DNA polymerase-alpha strongly and polymerases-delta and -epsilon less effectively. However, dideoxythymidine triphosphate, a specific inhibitor of DNA polymerase-beta, did not abrogate the KGF effect. Thus KGF increases DNA repair capacity in irradiated pulmonary epithelial cells, an effect mediated at least in part by DNA polymerases-alpha, -delta, and -epsilon. Enhancement of DNA repair capability after cell damage may be one mechanism by which KGF is able to ameliorate oxidant-mediated alveolar epithelial injury.

scholarly journals Influence of Acute Exercise on DNA Repair and PARP Activity before and after Irradiation in Lymphocytes from Trained and Untrained Individuals

2019 ◽  
Vol 20 (12) ◽  
pp. 2999 ◽  
Author(s):  
Maria Moreno-Villanueva ◽  
Andreas Kramer ◽  
Tabea Hammes ◽  
Maria Venegas-Carro ◽  
Patrick Thumm ◽  
...  
Keyword(s):  
Physical Activity ◽  
Dna Damage ◽  
Dna Repair ◽  
Immune Cells ◽  
Acute Exercise ◽  
Dna Strand Breaks ◽  
Strand Breaks ◽  
Before And After ◽  
Radiation Induced ◽  
Dna Strand

Several studies indicate that acute exercise induces DNA damage, whereas regular exercise increases DNA repair kinetics. Although the molecular mechanisms are not completely understood, the induction of endogenous reactive oxygen species (ROS) during acute exhaustive exercise due to metabolic processes might be responsible for the observed DNA damage, while an adaptive increase in antioxidant capacity due to regular physical activity seems to play an important protective role. However, the protective effect of physical activity on exogenously induced DNA damage in human immune cells has been poorly investigated. We asked the question whether individuals with a high aerobic capacity would have an enhanced response to radiation-induced DNA damage. Immune cells are highly sensitive to radiation and exercise affects lymphocyte dynamics and immune function. Therefore, we measured endogenous and radiation-induced DNA strand breaks and poly (ADP-ribose) polymerase-1 (PARP1) activity in peripheral blood mononuclear cells (PBMCs) from endurance-trained (maximum rate of oxygen consumption measured during incremental exercise V’O2max > 55 mL/min/kg) and untrained (V’O2max < 45 mL/min/kg) young healthy male volunteers before and after exhaustive exercise. Our results indicate that: (i) acute exercise induces DNA strand breaks in lymphocytes only in untrained individuals, (ii) following acute exercise, trained individuals repaired radiation-induced DNA strand breaks faster than untrained individuals, and (iii) trained subjects retained a higher level of radiation-induced PARP1 activity after acute exercise. The results of the present study indicate that increased aerobic fitness can protect immune cells against radiation-induced DNA strand breaks.

Determination of spatial patterns of DNA damage and repair in intestinal crypts by multi-cell gel electrophoresis

1996 ◽  
Vol 109 (8) ◽  
pp. 2061-2068
Author(s):  
R.A. Brooks ◽  
D.J. Winton
Keyword(s):  
Dna Damage ◽  
Gamma Radiation ◽  
Gel Electrophoresis ◽  
Topoisomerase Ii ◽  
Spatial Relationship ◽  
Dna Damage And Repair ◽  
Strand Breaks ◽  
Incremental Change ◽  
Radiation Induced ◽  
Dna Strand

We have developed a method to quantitate DNA strand breaks as a measure of DNA damage and repair in intact, isolated intestinal crypts. The assay is a modified form of the single-cell gel electrophoresis or ‘comet’ assay. By maintaining the spatial relationship between the cells we were able to characterise the repair response and the susceptibility to DNA damage of cells as a function of their position in the crypt. All cells were equally repair competent over the first 30 minutes of the repair of UV-C and gamma-radiation induced lesions. DNA damage was equally distributed following gamma-radiation but following incubation with the topoisomerase II inhibitor etoposide, damage was greater in the lower crypt with an unusual component to the comet tall which was tapered, implying an incremental change in susceptibility by cell position. This tapered component of the comet tail resolved rapidly after removal of etoposide. The pattern of damage produced by hydrogen peroxide was dose dependent with lower doses producing more strand breaks in the base of the crypt-an effect lost at higher doses. The assay has the ability to detect differences between cells in their susceptibility to DNA damage and their subsequent repair response which may vary with their proliferative or differentiative status.

scholarly journals Repair of DNA Strand Breaks by the Overlapping Functions of Lesion-Specific and Non-Lesion-Specific DNA 3′ Phosphatases

2001 ◽  
Vol 21 (21) ◽  
pp. 7191-7198 ◽  
Author(s):  
John R. Vance ◽  
Thomas E. Wilson
Keyword(s):  
Dna Damage ◽  
Oxidative Dna Damage ◽  
Synthetic Lethality ◽  
Dna Strand Breaks ◽  
Triple Mutant ◽  
Phosphatase Domain ◽  
Strand Breaks ◽  
Alternative Pathways ◽  
Processing Enzymes ◽  
Dna Strand

ABSTRACT In Saccharomyces cerevisiae, the apurinic/apyrimidinic (AP) endonucleases Apn1 and Apn2 act as alternative pathways for the removal of various 3′-terminal blocking lesions from DNA strand breaks and in the repair of abasic sites, which both result from oxidative DNA damage. Here we demonstrate that Tpp1, a homologue of the 3′ phosphatase domain of polynucleotide kinase, is a third member of this group of redundant 3′ processing enzymes. Unlike Apn1 and Apn2, Tpp1 is specific for the removal of 3′ phosphates at strand breaks and does not possess more general 3′ phosphodiesterase, exonuclease, or AP endonuclease activities. Deletion ofTPP1 in an apn1 apn2 mutant background dramatically increased the sensitivity of the double mutant to DNA damage caused by H2O2 and bleomycin but not to damage caused by methyl methanesulfonate. The triple mutant was also deficient in the repair of 3′ phosphate lesions left by Tdp1-mediated cleavage of camptothecin-stabilized Top1-DNA covalent complexes. Finally, the tpp1 apn1 apn2 triple mutation displayed synthetic lethality in combination with rad52, possibly implicating postreplication repair in the removal of unrepaired 3′-terminal lesions resulting from endogenous damage. Taken together, these results demonstrate a clear role for the lesion-specific enzyme, Tpp1, in the repair of a subset of DNA strand breaks.

scholarly journals Evaluation of the Protective Effects of Quercetin, Rutin, Naringenin, Resveratrol and Trolox Against Idarubicin-Induced DNA Damage

2010 ◽  
Vol 13 (2) ◽  
pp. 231 ◽  
Author(s):  
Haydar Çelik ◽  
Emel Arinç
Keyword(s):  
Dna Damage ◽  
Cytochrome P450 ◽  
Mitomycin C ◽  
Dna Strand Breaks ◽  
Protective Effects ◽  
Cytochrome P450 Reductase ◽  
Strand Breaks ◽  
P450 Reductase ◽  
Nadph Cytochrome P450 Reductase ◽  
Dna Strand

PURPOSE. Idarubicin is a synthetic anthracycline anticancer drug widely used in the treatment of some hematological malignancies. The studies in our laboratory have clearly demonstrated that idarubicin can undergo reductive bioactivation by NADPH-cytochrome P450 reductase to free radicals with resulting formation of DNA strand breaks, which can potentially contribute to its genotoxic effects [Çelik, H., Arinç, E., Bioreduction of idarubicin and formation of ROS responsible for DNA cleavage by NADPH-cytochrome P450 reductase and its potential role in the antitumor effect. J Pharm Pharm Sci, 11(4):68-82, 2008]. In the current study, our aim was to investigate the possible protective effects of several phenolic antioxidants, quercetin, rutin, naringenin, resveratrol and trolox, against the DNA-damaging effect of idarubicin originating from its P450 reductase-catalyzed bioactivation. METHODS. DNA damage was measured by detecting single-strand breaks in plasmid pBR322 DNA using a cell-free agarose gel method. RESULTS. Our results indicated that, among the compounds tested, quercetin was the most potent antioxidant in preventing DNA damage. Quercetin significantly decreased the extent of DNA strand breaks in a dose-dependent manner; 100 μM of quercetin almost completely inhibited the DNA strand breakage. Unlike quercetin, its glycosidated conjugate rutin, failed to provide any significant protection against idarubicin-induced DNA strand breaks except at the highest concentration tested (2 mM). The protective effects of other antioxidants were significantly less than that of quercetin even at high concentrations. Quercetin was found to be also an effective protector against DNA damage induced by mitomycin C. CONCLUSION. We conclude that quercetin, one of the most abundant flavonoids in the human diet, is highly effective in reducing the DNA damage caused by the antitumor agents, idarubicin and mitomycin C, following bioactivation by P450 reductase.

scholarly journals Protective Activity of C-Geranylflavonoid Analogs from Paulownia tomentosa against DNA Damage in 137Cs Irradiated AHH-1Cells

2014 ◽  
Vol 9 (9) ◽  
pp. 1934578X1400900
Author(s):  
Hyung-In Moon ◽  
Min Ho Jeong ◽  
Wol Soon Jo
Keyword(s):  
Dna Damage ◽  
Protective Effects ◽  
Strand Breaks ◽  
Human Lymphoblastoid Cell ◽  
Wide Range ◽  
Radiation Induced ◽  
Anti Oxidant ◽  
Dna Strand ◽  
Cellular Dna

Radiotherapy is an important form of treatment for a wide range of cancers, but it can damage DNA and cause adverse effects. We investigated if the diplacone analogs of P. tomentosa were radio-protective in a human lymphoblastoid cell line (AHH-1). Four geranylated flavonoids, diplacone, 3′- O-methyl-5′-hydroxydiplacone, 3′- O-methyl-5′- O-methyldiplacone and 3′- O-methyldiplacol, were tested for their antioxidant and radio-protective effects. Diplacone analogs effectively scavenged free radicals and inhibited radiation-induced DNA strand breaks in vitro. They significantly decreased levels of reactive oxygen species and cellular DNA damage in 2 Gy-irradiated AHH-1 cells. Glutathione levels and superoxide dismutase activity in irradiated AHH-1 cells increased significantly after treatment with these analogs. The enhanced biological anti-oxidant activity and radioprotective activity of diplacone analogs maintained the survival of irradiated AHH-1 cells in a clonogenic assay. These data suggest that diplacone analogs may protect healthy tissue surrounding tumor cells during radiotherapy to ensure better control of radiotherapy and allow higher doses of radiotherapy to be employed.

scholarly journals The role of Sp1 in the detection and elimination of cells with persistent DNA strand breaks

NAR Cancer ◽  
2020 ◽  
Vol 2 (2) ◽  
Author(s):  
Polina S Loshchenova ◽  
Svetlana V Sergeeva ◽  
Sally C Fletcher ◽  
Grigory L Dianov
Keyword(s):  
Dna Damage ◽  
Cancer Therapy ◽  
Genome Stability ◽  
Dna Strand Breaks ◽  
Dna Lesions ◽  
Exogenous Dna ◽  
Strand Breaks ◽  
Specificity Factor ◽  
Dna Strand

Abstract Maintenance of genome stability suppresses cancer and other human diseases and is critical for organism survival. Inevitably, during a life span, multiple DNA lesions can arise due to the inherent instability of DNA molecules or due to endogenous or exogenous DNA damaging factors. To avoid malignant transformation of cells with damaged DNA, multiple mechanisms have evolved to repair DNA or to detect and eradicate cells accumulating unrepaired DNA damage. In this review, we discuss recent findings on the role of Sp1 (specificity factor 1) in the detection and elimination of cells accumulating persistent DNA strand breaks. We also discuss how this mechanism may contribute to the maintenance of physiological populations of healthy cells in an organism, thus preventing cancer formation, and the possible application of these findings in cancer therapy.

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