scholarly journals Radiation dose determines the method for quantification of DNA double strand breaks

2016 ◽  
Vol 88 (1) ◽  
pp. 127-136 ◽  
Author(s):  
TANJA BULAT ◽  
OTILIJA KETA ◽  
LELA KORIĆANAC ◽  
JELENA ŽAKULA ◽  
IVAN PETROVIĆ ◽  
...  
Keyword(s):  
Radiation Dose ◽  
Western Blot ◽  
Blot Analysis ◽  
Western Blot Analysis ◽  
Immunofluorescence Microscopy ◽  
Double Strand Breaks ◽  
Immunofluorescent Staining ◽  
Dna Double Strand Breaks ◽  
Strand Breaks ◽  
Γh2ax Foci

ABSTRACT Ionizing radiation induces DNA double strand breaks (DSBs) that trigger phosphorylation of the histone protein H2AX (γH2AX). Immunofluorescent staining visualizes formation of γH2AX foci, allowing their quantification. This method, as opposed to Western blot assay and Flow cytometry, provides more accurate analysis, by showing exact position and intensity of fluorescent signal in each single cell. In practice there are problems in quantification of γH2AX. This paper is based on two issues: the determination of which technique should be applied concerning the radiation dose, and how to analyze fluorescent microscopy images obtained by different microscopes. HTB140 melanoma cells were exposed to γ-rays, in the dose range from 1 to 16 Gy. Radiation effects on the DNA level were analyzed at different time intervals after irradiation by Western blot analysis and immunofluorescence microscopy. Immunochemically stained cells were visualized with two types of microscopes: AxioVision (Zeiss, Germany) microscope, comprising an ApoTome software, and AxioImagerA1 microscope (Zeiss, Germany). Obtained results show that the level of γH2AX is time and dose dependent. Immunofluorescence microscopy provided better detection of DSBs for lower irradiation doses, while Western blot analysis was more reliable for higher irradiation doses. AxioVision microscope containing ApoTome software was more suitable for the detection of γH2AX foci.

3H-Thymidine Influence on DNA Double Strand Breaks Induction in Cultured Human Mesenchymal Stem Cells

2018 ◽  
Vol 63 (1) ◽  
pp. 28-34 ◽  
Author(s):  
Н. Воробьева ◽  
N. Vorob'eva ◽  
В. Уйба ◽  
V. Uyba ◽  
О. Кочетков ◽  
...  
Keyword(s):  
Stem Cells ◽  
Culture Medium ◽  
Specific Radioactivity ◽  
Human Mesenchymal Stem Cells ◽  
Living Cells ◽  
Double Strand Breaks ◽  
Dna Double Strand Breaks ◽  
Strand Breaks ◽  
Immunocytochemical Analysis ◽  
Γh2ax Foci

Purpose: To estimate the impact of 3H-thymidine on DNA double strand breaks (DSBs) induction in cultured human mesenchymal stem cells (MSC). Material and methods: Isolation and cultivation of human bone marrow MSC was carried out according to a standard procedure. A sterile solution of 3H-thymidine with different specific radioactivity was added to the cell culture and incubated under the conditions of the CO2 incubator for 24 hours. The specific radioactivity of 3H-thymidine in the incubation medium was 50–1600 kBq/ml. To evaluate quantitatively the DSBs, an immunocytochemical analysis of the DSB marker – γH2AX foci histone was used. Additionally, the proportion of dividing cells was estimated using an immunocytochemical analysis of the cell proliferation marker, the Ki67 protein. Results: It was shown that 24 h incubation of human MSC in a culture medium results in a dose-dependent increase in γH2AX foci. There is a linear increase in the foci γH2AX in the range of 50–400 kBq/ml, after which the relative quantitative yield of foci per unit of specific radioactivity begins to decrease. In general, the dose-effect relationship is approximated by the quadratic function y = 3.13 + 50.80x – 12.38x2 (R2 = 0.99), where y is the number of foci γH2AX in the cell nucleus, and x is the specific radioactivity in 1000 kBq/ml. It was found that incubation of human MSC in a culture medium containing 800 and 1600 kBq/ml of 3H-thymidine resulted in a statistically significant decrease in the cells proliferative activity compared to the control of ~1.25 and 1.41 respectively. The peculiar biological limitation of tritium accumulation in the cell nucleus explains well the nonlinear character of the dependence of the formation of DSBs on the specific radioactivity of 3H-thymidine in the culture medium observed in our study. Conclusion: Quantitative analysis of γH2AX foci has proved to be a highly reproducible and highly sensitive method for evaluating the induction of DSBs in living cells under the action of 3H-thymidine. An analysis of the foci of γH2AX will be useful for accurate estimating the quantitative yield of DBS in living cells per dose of 3H-thymidine β-radiation. To do this, it is necessary to make a correct calculation of the doses received by the cells taking into account the microdistribution of 3H-thymidine in the cell volume and its accumulation in the DNA of living cells.

scholarly journals Radiation-induced DNA double-strand breaks in peripheral leukocytes and therapeutic response of heel spur patients treated by orthovoltage X-rays or a linear accelerator

2020 ◽  
Vol 196 (12) ◽  
pp. 1116-1127
Author(s):  
Sebastian Zahnreich ◽  
Hans-Peter Rösler ◽  
Carina Schwanbeck ◽  
Heiko Karle ◽  
Heinz Schmidberger
Keyword(s):  
Linear Accelerator ◽  
Double Strand Breaks ◽  
X Rays ◽  
Dna Double Strand Breaks ◽  
Heel Spur ◽  
Strand Breaks ◽  
Γh2ax Foci ◽  
Radiation Induced ◽  
Peripheral Leukocytes ◽  
Painful Heel

Abstract Purpose Biodosimetric assessment and comparison of radiation-induced deoxyribonucleic acid (DNA) double-strand breaks (DSBs) by γH2AX immunostaining in peripheral leukocytes of patients with painful heel spur after radiation therapy (RT) with orthovoltage X‑rays or a 6-MV linear accelerator (linac). The treatment response for each RT technique was monitored as a secondary endpoint. Patients and methods 22 patients were treated either with 140-kV orthovoltage X‑rays (n = 11) or a 6-MV linac (n = 11) with two weekly fractions of 0.5 Gy for 3 weeks. In both scenarios, the dose was prescribed to the International Commission on Radiation Units and Measurements (ICRU) dose reference point. Blood samples were obtained before and 30 min after the first RT session. γH2AX foci were quantified by immunofluorescence microscopy to assess the yield of DSBs at the basal level and after radiation exposure ex vivo or in vivo. The treatment response was assessed before and 3 months after RT using a five-level functional calcaneodynia score. Results RT for painful heel spurs induced a very mild but significant increase of γH2AX foci in patients’ leukocytes. No difference between the RT techniques was observed. High and comparable therapeutic responses were documented for both treatment modalities. This trial was terminated preliminarily after an interim analysis (22 patients randomized). Conclusion Low-dose RT for painful heel spurs with orthovoltage X‑rays or a 6-MV linac is an effective treatment option associated with a very low and comparable radiation burden to the patient, as confirmed by biodosimetric measurements.

Abstract 1052: 26S Proteasome: Intracellular Localization and Regulation by Nitric Oxide

Circulation ◽  
2007 ◽  
Vol 116 (suppl_16) ◽  
Author(s):  
Muneera R Kapadia ◽  
Jason W Eng ◽  
Jozef Murar ◽  
Qun Jiang ◽  
Melina R Kibbe
Keyword(s):  
Protein Expression ◽  
Western Blot ◽  
Blot Analysis ◽  
Western Blot Analysis ◽  
Intracellular Localization ◽  
26S Proteasome ◽  
Immunofluorescent Staining ◽  
Vsmc Proliferation ◽  
Proteasome Subunits ◽  
The Relationship

Introduction: Nitric oxide (NO) is known to inhibit vascular smooth muscle cell (VSMC) proliferation by modulating cell cycle proteins. The 26S proteasome tightly regulates the degradation of most cell cycle proteins. Therefore, we previously studied the relationship between NO and the 26S proteasome, and found that NO directly inhibits 26S proteasome catalytic activity. The purpose of this study was two-fold: to determine the effect of NO on 26S proteasome subunit expression, and to determine the intracellular localization of these subunits. Methods: Protein expression was examined using western blot analysis conducted on rat aortic VSMC exposed to varying concentrations of the NO donor S-nitroso-N-acetylpenicillamine (SNAP, 125–1000 μM) for 24 hours. Intracellular localization was conducted with immunofluorescent staining of VSMC ± exposure to SNAP (500 μM). VSMC were also fractionated into their nuclear and cytoplasmic components and western blot analysis was conducted to confirm localization. Results: Of the 26S proteasome subunits examined, the α5, α6, β1, and inducible β1 subunits demonstrated increased protein expression with increasing concentrations of NO. However, β2, inducible β2, β5, and inducible β5 protein expression did not change with NO exposure. Immunofluorescent staining of VSMC for these subunits confirmed these results. Additionally, each of these subunits showed a distinct pattern of staining: the α5 subunit was mostly perinuclear, the α6 subunit appeared mostly nuclear, and the β1 and inducible β1 subunits were mostly cytoplasmic. Western blot analysis following nuclear and cytoplasmic separation confirmed that α5, β1, and inducible β1 subunits were mostly in the cytoplasmic fraction. Interestingly, while the α6 subunit localizes to the nucleus by immunofluorescent staining, western blotting showed it to be mostly in the cytoplasmic fraction, indicating that its cellular distribution is perinuclear. Conclusion: Our data indicate that the 26S proteasome subunits have distinct patterns of intracellular localization, and are differentially regulated by NO. Understanding the relationship between NO and the 26S proteasome provides insight into the mechanism by which NO inhibits VSMC proliferation.

Galectin-1 induces chemokine production and proliferation in pancreatic stellate cells

2006 ◽  
Vol 290 (4) ◽  
pp. G729-G736 ◽  
Author(s):  
Atsushi Masamune ◽  
Masahiro Satoh ◽  
Jun Hirabayashi ◽  
Kenichi Kasai ◽  
Kennichi Satoh ◽  
...  
Keyword(s):  
Western Blot ◽  
Blot Analysis ◽  
Western Blot Analysis ◽  
Stellate Cells ◽  
Pancreatic Tissue ◽  
Immunofluorescent Staining ◽  
Pancreatic Stellate Cells ◽  
Chemokine Production ◽  
Cell Functions

Galectin-1 is a β-galactoside-binding lectin. Previous studies have shown that galectin-1 was expressed in fibroblasts of chronic pancreatitis and of desmoplastic reaction associated with pancreatic cancer. These fibroblasts are now recognized as activated pancreatic stellate cells (PSCs). Here, we examined the role of galectin-1 in cell functions of PSCs. PSCs were isolated from rat pancreatic tissue and used in their culture-activated phenotype unless otherwise stated. Expression of galectin-1 was assessed by Western blot analysis, RT-PCR, and immunofluorescent staining. The effects of recombinant galectin-1 on chemokine production and proliferation were evaluated. Activation of transcription factors was assessed by EMSA. Activation of MAPKs was examined by Western blot analysis using anti-phosphospecific antibodies. Galectin-1 was strongly expressed in culture-activated but not freshly isolated PSCs. Recombinant galectin-1 increased proliferation and production of monocyte chemoattractant protein-1 and cytokine-induced neutrophil chemoattractant-1. Galectin-1 activated ERK, JNK, activator protein-1, and NF-κB, but not p38 MAPK or Akt. Galectin-1 induced proliferation through ERK and chemokine production mainly through the activation of NF-κB and in part by JNK and ERK pathways. These effects of galectin-1 were abolished in the presence of thiodigalactosie, an inhibitor of β-galactoside binding. In conclusion, our results suggest a role of galectin-1 in chemokine production and proliferation through its β-galactoside binding activity in activated PSCs.

scholarly journals The role of activating transcription factor 6 in hydroxycamptothecin-induced fibroblast autophagy and apoptosis

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Jin Tao ◽  
Hui Chen ◽  
Xiaolei Li ◽  
Jingcheng Wang
Keyword(s):  
Transcription Factor ◽  
Western Blot ◽  
Blot Analysis ◽  
Western Blot Analysis ◽  
Cell Counting ◽  
Immunofluorescent Staining ◽  
Fibroblast Proliferation ◽  
Activating Transcription Factor ◽  
Related Proteins

Abstract Background The over-proliferation of fibroblasts is considered to be the main cause of scar adhesion after joint surgery. Hydroxycamptothecin (HCPT), though as a potent antineoplastic drug, shows preventive effects on scar adhesion. This study aimed to investigate the role of activating transcription factor 6 (ATF-6) in the HCPT-induced inhibition of fibroblast viability. Methods The cell counting kit-8 (CCK-8) assay, western blot analysis, lentivirus-mediated gene silencing, transmission electron microscopy (TEM) analysis, immunofluorescent staining for autophagy-related protein light chain 3 (LC3) were used to explore the effect of HCPT on triggering fibroblast apoptosis and inhibiting fibroblast proliferation, and the involvement of possible signaling pathways. Results It was found that HCPT exacerbated fibroblast apoptosis and repressed its proliferation. Subsequently, endoplasmic reticulum stress (ERS)-related proteins were determined by western blot prior to ATF6 p50 was screened out and reexamined after it was silenced. As a result, ATF6-mediated ERS played a role in HCPT-induced fibroblast apoptosis. Autophagy-related proteins and autophagosomes were detected after the HCPT administration using western blot and TEM analyses, respectively. Autophagy was activated after the HCPT treatment. With the co-treatment of autophagy inhibitor 3-methyladenine (3-MA), both the western blot analysis and the CCK-8 assay showed inhibited autophagy, which indicated that the effect of HCPT on fibroblast proliferation was partially reversed. Besides, the LC3 immunofluorescence staining revealed suppressed autophagy after silencing ATF6 p50. Conclusion Our results demonstrate that HCPT acts as a facilitator of fibroblast apoptosis and inhibitor of fibroblast proliferation for curbing the postoperative scar adhesion, in which the ATF6-mediated ERS pathway and autophagy are involved.

Induction and rejoining of DNA double-strand breaks in the lymphocytes of prostate cancer patients after radium-223 treatment as assessed by the γH2AX foci assay

2019 ◽  
Vol 58 (05) ◽  
pp. 387-394
Author(s):  
Roswitha Runge ◽  
Liane Oehme ◽  
Sabine Grosche-Schlee ◽  
Anja Braune ◽  
Robert Freudenberg ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Cancer Patients ◽  
Ex Vivo ◽  
Double Strand Breaks ◽  
Patient Specific ◽  
Dna Double Strand Breaks ◽  
Strand Breaks ◽  
Γh2ax Foci ◽  
Radium 223 ◽  
Radiation Induced

Abstract Aim The aim of this study is to assess if the number of radiation-induced double strand breaks (DSB) in lymphocytes of prostate cancer patients is affected after repeated Ra-223 therapies. In addition, we investigated the repair of ex vivo induced DSB to investigate the repair proficiency in patient’s lymphocytes over the therapy course. Methods Before each of six therapy cycles, blood samples were obtained from seventeen patients. After separation of lymphocytes, the cells were subjected to immunofluorescence staining for detection of DSB-marking γH2AX foci. The number of foci per cell per patient sample was determined for each cycle (X1-X6, baseline foci per cell). Additionally, appropriate samples were exposed ex vivo to an X-ray dose of 1 Gy. The number of γH2AX foci per cell were analyzed after 0.5 h, 2 h and 24 h of recovery. Results Patient-specific linear regression of the baseline foci per cell over the therapy cycles revealed no significant slopes in the regression lines. Likewise, the mean baseline foci per cell of all patients for cycles X2-X6 was not significantly elevated in comparison to the pre-therapeutic value (X1). The differences between the percentages of residual DSB and cycles were not significant, both at 2 h and 24 h repair time. Consideration of the X6/X1 ratios of both the number of lymphocytes and the amount of residual damage at 24 h indicated a significant correlation. Conclusion Our findings indicate that the number of γH2AX foci per cell was not changed in dependence on the Ra-223 therapy cycles. The ability of patient’s lymphocytes to repair ex vivo induced DSB remained unaffected throughout the entire therapy course.

scholarly journals Transient Global Ischemia Triggers Expression of the DNA Damage-Inducible Gene GADD45 in the Rat Brain

1998 ◽  
Vol 18 (6) ◽  
pp. 646-657 ◽  
Author(s):  
Jun Chen ◽  
Koichi Uchimura ◽  
R. Anne Stetler ◽  
Raymond L. Zhu ◽  
Masaki Nakayama ◽  
...  
Keyword(s):  
Dna Damage ◽  
Cell Death ◽  
Blot Analysis ◽  
Double Strand Breaks ◽  
Dna Double Strand Breaks ◽  
Transient Ischemia ◽  
Strand Breaks ◽  
Transient Global Ischemia ◽  
Inducible Gene

Using in situ hybridization, Northern blot analysis, Western blot analysis, and immunocytochemistry, mRNA and protein expression of the novel DNA damage-inducible gene GADD45 was examined in the rat brain at 0.5, 2, 4, 8, 16, 24, 48, and 72 hours after 15 minutes of transient global ischemia. Transient ischemia produced by the four-vessel occlusion method resulted in DNA double-strand breaks and delayed neuronal cell death in vulnerable neurons of the hippocampal CA1 sector, the hilus, dorsal caudate-putamen, and thalamus, as shown by in situ DNA nick end-labeling and histologic staining. GADD45 mRNA was transiently increased in less-vulnerable regions such as the parietal cortex (up to 8 hours after ischemia) and dentate granule cells (up to 24 hours after ischemia) but was persistently increased in vulnerable neurons such as CA1 pyramidal neurons (up to 48 hours). GADD45 immunoreactivity was increased in both vulnerable and less-vulnerable regions at earlier reperfusion periods (4 to 16 hours), but thereafter immunoreactivity was decreased below control levels in most vulnerable regions before delayed cell death and DNA double-strand breaks. At 72 hours after transient ischemia, a moderate increase in GADD45 immunoreactivity was still detectable in some CA3 neurons and in a few surviving neurons in the CA1 region. Double staining performed at 16 to 72 hours after ischemia revealed that GADD45 immunoreactivity was persistently increased in neurons that did not develop DNA damage. Because GADD45 protein may participate in the DNA excision repair process and because it has been shown that this protein is also overexpressed in neurons that survive focal ischemia and kainate-induced epileptic seizures, the results reported here support the hypothesis that GADD45 could have a protective role in neuronal injury.

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