Similar Datasets
Project description:Radiation therapy is commonly used to treat glioblastoma multiforme (GBM) brain tumor. Ionizing radiation (IR) induces dose- specific variations in transcriptional programs, implicating they are tightly regulated and critical components in the tumor response and survival. Yet, our understanding of the downstream molecular events triggered by lethal vs sublethal IR doses is limited. Herein, we report that variations in the genetic programs are positively and functionally correlated with the exposure to lethal or sublethal IR doses. Genome architecture analysis revealed that gene regulation is spatially and temporally coordinated with DNA repair kinetics. Radiation-activated genes were pre-positioned in active sub-nuclear compartments and were up-regulated following DNA damage response, while the DNA repair activity shifted to the inactive heterochromatic spatial compartments. The IR dose affected the levels of DNA damage repair and transcription modulation, but not the order of events, which was linked to their spatial nuclear positioning. Thus, distinct coordinated temporal dynamics of DNA damage repair and transcription reprogramming in the active and inactive sub-nuclear compartments highlight the importance of high-order genome organization in synchronizing the molecular events following IR.
2024-01-29 | GSE244666 | GEO
Project description:Radiation therapy is commonly used to treat glioblastoma multiforme (GBM) brain tumor. Ionizing radiation (IR) induces dose- specific variations in transcriptional programs, implicating they are tightly regulated and critical components in the tumor response and survival. Yet, our understanding of the downstream molecular events triggered by lethal vs sublethal IR doses is limited. Herein, we report that variations in the genetic programs are positively and functionally correlated with the exposure to lethal or sublethal IR doses. Genome architecture analysis revealed that gene regulation is spatially and temporally coordinated with DNA repair kinetics. Radiation-activated genes were pre-positioned in active sub-nuclear compartments and were up-regulated following DNA damage response, while the DNA repair activity shifted to the inactive heterochromatic spatial compartments. The IR dose affected the levels of DNA damage repair and transcription modulation, but not the order of events, which was linked to their spatial nuclear positioning. Thus, distinct coordinated temporal dynamics of DNA damage repair and transcription reprogramming in the active and inactive sub-nuclear compartments highlight the importance of high-order genome organization in synchronizing the molecular events following IR.
2024-01-29 | GSE244868 | GEO
Project description:Epidermal growth factor receptor (EGFR) overexpression is associated with resistance to chemotherapy and radiotherapy. It modulates DNA repair after radiation-induced damage through association with the catalytic subunit of DNA protein kinase (DNA-PKcs). We investigated the role of EGFR nuclear import and its association with DNA-PKcs on DNA repair after exposure to cisplatin or ionizing radiation (IR). The model system was based on EGFR-null murine NIH3T3 fibroblasts in which EGFR expression was restored with isoforms that were wild-type (wt), derived from human cancers (L858R, EGFRvIII), or mutated in the nuclear localization signal (NLS) sequence. In cells expressing wtEGFR or EGFRvIII, there was complete unhooking of cisplatin-induced interstrand cross-links and repair of IR-induced strand breaks. In contrast, cells expressing L858R or NLS mutations showed reduced unhooking of interstrand cross-links and repair of strand breaks. Immunoprecipitation showed wtEGFR and EGFRvIII binding to DNA-PKcs, increasing 2-fold 18 hours after cisplatin therapy. Confocal microscopy and proximity ligation assay showed that this interaction in the cytoplasm and nucleus was associated with increased DNA protein kinase complex (DNA-PK) activity. Cells expressing the EGFR L858R mutation, which has constitutive kinase activity, exhibited reduced DNA repair without nuclear localization. EGFR-NLS mutants showed impaired nuclear localization and DNA-PKcs association with reduced DNA repair and DNA-PK kinase activity. In summary, EGFR nuclear localization was required for modulation of cisplatin and IR-induced repair of DNA damage. EGFR-DNA-PKcs binding was induced by cisplatin or IR but not by EGFR nuclear translocation per se. Our findings show that EGFR subcellular distribution can modulate DNA repair kinetics, with implications for design of EGFR-targeted combinational therapies.
| S-EPMC3033323 | biostudies-literature
Project description:PURPOSE:Ionizing radiation induced foci (IRIF) known also as DNA repair foci represent most sensitive endpoint for assessing DNA double strand breaks (DSB). IRIF are usually visualized and enumerated with the aid of fluorescence microscopy using antibodies to ?H2AX and 53BP1. This study analyzed effect of low dose ionizing radiation on residual IRIF in human lymphocytes to the aim of potential biodosimetry and possible extrapolation of high-dose ?H2AX/53BP1 effects to low doses and compared kinetics of DSB and IRIF. We also analyzed whether DNaseI, which is used for reducing of clumps, affects the IRIF level. MATERIALS AND METHODS:The cryopreserved human lymphocytes from umbilical cord blood (UCB) were thawed with/without DNaseI, ?-irradiated at doses of 0, 5, 10, and 50 cGy and ?H2AX/53BP1 foci were analyzed 30 min, 2 h, and 22 h post-irradiation using appropriate antibodies. We also analyzed kinetics of DSB using PFGE. RESULTS:No significant difference was observed between data obtained by ?H2AX foci evaluation in cells that were irradiated by low doses and data obtained by extrapolation from higher doses. Residual 53BP1 foci induced by low doses significantly outreached the data extrapolated from irradiation by higher doses. 53BP1 foci induced by low dose-radiation remain longer at DSB loci than foci induced by higher doses. There was no significant effect of DNaseI on DNA repair foci. CONCLUSIONS:Primary ?H2AX, 53BP1 foci and their co-localization represent valuable markers for biodosimetry of low doses, but their usefulness is limited by short time window. Residual ?H2AX and 53BP1 foci are more useful markers for biodosimetry in vitro. Effects of low doses can be extrapolated from high dose using ?H2AX residual foci while ?H2AX/53BP1 foci are valuable markers for evaluation of initial DSB induced by ionizing radiation. Residual IRIF induced by low doses persist longer time than those induced by higher doses.
| S-EPMC7016656 | biostudies-literature
Project description:Exposure to ionizing radiation associated with highly energetic and charged heavy particles is an inherent risk astronauts face in long duration space missions. We have previously considered the transcriptional effects that three levels of radiation (0.3 Gy, 1.5 Gy, and 3.0 Gy) have at an immediate time point (1 hr) post-exposure [1]. Our analysis of these results suggest effects on transcript levels that could be modulated at lower radiation doses [2]. In addition, a time dependent effect is likely to be present. Therefore, in order to develop a lab-on-a-chip approach for detection of radiation exposure in terms of both radiation level and time since exposure, we developed a time- and dose-course study to determine appropriate sensitive and specific transcript biomarkers that are detectable in blood samples. The data described herein was developed from a study measuring exposure to 0.15 Gy, 0.30 Gy, and 1.5 Gy of radiation at 1 hr, 2 hr, and 6 hr post-exposure using Affymetrix® GeneChip® PrimeView™ microarrays. This report includes raw gene expression data files from the resulting microarray experiments representing typical radiation exposure levels an astronaut may experience as part of a long duration space mission. The data described here is available in NCBI's Gene Expression Omnibus (GEO), accession GSE63952.
| S-EPMC6806397 | biostudies-literature
Project description:Pyrrole-imidazole (Py-Im) polyamides are synthetic non-genotoxic minor groove-binding small molecules. We hypothesized that Py-Im polyamides can modulate the cellular response to ionizing radiation. Pre-treatment of cells with a Py-Im polyamide prior to exposure to ionizing radiation resulted in a delay in resolution of phosphorylated ?-H2AX foci, increase in XRCC1 foci, and reduced cellular replication potential. RNA-sequencing of cell lines exposed to the polyamide showed induction of genes related to the ultraviolet radiation response. We observed that the polyamide is almost 10-fold more toxic to a cell line deficient in DNA ligase 3 as compared to the parental cell line. Alkaline single cell gel electrophoresis reveals that the polyamide induces genomic fragmentation in the ligase 3 deficient cell line but not the corresponding parental line. The polyamide interferes directly with DNA ligation in vitro. We conclude that Py-Im polyamides may be further explored as sensitizers to genotoxic therapies.
| S-EPMC5929528 | biostudies-literature
Project description:Extrachromosomal DNA can integrate into the genome with no sequence specificity producing an insertional mutation. This process, which is referred to as random integration (RI), requires a double stranded break (DSB) in the genome. Inducing DSBs by various means, including ionizing radiation, increases the frequency of integration. Here we report that non-lethal physiologically relevant doses of ionizing radiation (10-100 mGy), within the range produced by medical imaging equipment, stimulate RI of transfected and viral episomal DNA in human and mouse cells with an extremely high efficiency. Genetic analysis of the stimulated RI (S-RI) revealed that it is distinct from the background RI, requires histone H2AX S139 phosphorylation (?H2AX) and is not reduced by DNA polymerase ? (Polq) inactivation. S-RI efficiency was unaffected by the main DSB repair pathway (homologous recombination and non-homologous end joining) disruptions, but double deficiency in MDC1 and 53BP1 phenocopies ?H2AX inactivation. The robust responsiveness of S-RI to physiological amounts of DSBs can be exploited for extremely sensitive, macroscopic and direct detection of DSB-induced mutations, and warrants further exploration in vivo to determine if the phenomenon has implications for radiation risk assessment.
| S-EPMC6964834 | biostudies-literature
Project description:By directed evolution in the laboratory, we previously generated populations of Escherichia coli that exhibit a complex new phenotype, extreme resistance to ionizing radiation (IR). The molecular basis of this extremophile phenotype, involving strain isolates with a 3-4 order of magnitude increase in IR resistance at 3000 Gy, is now addressed. Of 69 mutations identified in one of our most highly adapted isolates, functional experiments demonstrate that the IR resistance phenotype is almost entirely accounted for by only three of these nucleotide changes, in the DNA metabolism genes recA, dnaB, and yfjK. Four additional genetic changes make small but measurable contributions. Whereas multiple contributions to IR resistance are evident in this study, our results highlight a particular adaptation mechanism not adequately considered in studies to date: Genetic innovations involving pre-existing DNA repair functions can play a predominant role in the acquisition of an IR resistance phenotype. DOI: http://dx.doi.org/10.7554/eLife.01322.001.
| S-EPMC3939492 | biostudies-literature
Project description:Risk factors for thyroid cancer remain largely unknown except for ionizing radiation exposure during childhood and a history of benign thyroid nodules. Because thyroid nodules are more common than thyroid cancers and are associated with thyroid cancer risk, we evaluated several polymorphisms potentially relevant to thyroid tumors and assessed interaction with ionizing radiation exposure to the thyroid gland. Thyroid nodules were detected in 1998 by ultrasound screening of 2997 persons who lived near the Semipalatinsk nuclear test site in Kazakhstan when they were children (1949-1962). Cases with thyroid nodules (n = 907) were frequency matched (1:1) to those without nodules by ethnicity (Kazakh or Russian), gender and age at screening. Thyroid gland radiation doses were estimated from fallout deposition patterns, residence history and diet. We analyzed 23 polymorphisms in 13 genes and assessed interaction with ionizing radiation exposure using likelihood ratio tests (LRT). Elevated thyroid nodule risks were associated with the minor alleles of RET S836S (rs1800862, P = 0.03) and GFRA1 -193C>G (rs not assigned, P = 0.05) and decreased risk with XRCC1 R194W (rs1799782, P trend = 0.03) and TGFB1 T263I (rs1800472, P = 0.009). Similar patterns of association were observed for a small number of papillary thyroid cancers (n = 25). Ionizing radiation exposure to the thyroid gland was associated with significantly increased risk of thyroid nodules (age and gender adjusted excess odds ratio/Gy = 0.30, 95% CI 0.05-0.56), with evidence for interaction by genotype found for XRCC1 R194W (LRT P value = 0.02). Polymorphisms in RET signaling, DNA repair and proliferation genes may be related to risk of thyroid nodules, consistent with some previous reports on thyroid cancer. Borderline support for gene-radiation interaction was found for a variant in XRCC1, a key base excision repair protein. Other pathways such as genes in double-strand break repair, apoptosis and genes related to proliferation should also be pursued.
| S-EPMC2875679 | biostudies-literature
Project description:The superior dose distribution of particle radiation compared to photon radiation makes it a promising therapy for the treatment of tumors. However, the cellular responses to particle therapy and especially the DNA damage response (DDR) is not well characterized. Compared to photons, particles are thought to induce more closely spaced DNA lesions instead of isolated lesions. How this different spatial configuration of the DNA damage directs DNA repair pathway usage, is subject of current investigations. In this review, we describe recent insights into induction of DNA damage by particle radiation and how this shapes DNA end processing and subsequent DNA repair mechanisms. Additionally, we give an overview of promising DDR targets to improve particle therapy.
| S-EPMC8514742 | biostudies-literature