FLASH-RT does not affect chromosome translocations and junction structures beyond that of CONV-RT dose-rates
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PROVIDER: PRJNA945099 | ENA |
REPOSITORIES: ENA
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Project description:The molecular and cellular mechanisms driving the enhanced therapeutic ratio of ultra-high dose-rate radiotherapy (FLASH-RT) over slower conventional (CONV) ionizing radiation (IR) dose-rate are not known. However, attenuated DNA damage and transient oxygen depletion are among a number of proposed models. Here, we tested whether FLASH-IR under physioxic (4% O2) and hypoxic conditions (≤2% O2) attenuates detection of genome-wide translocations relative to CONV dose rates and whether any differences identified revert under normoxic (21% O2) conditions. We employed high-throughput rejoin and genome-wide translocation sequencing (HTGTS-JoinT-seq), usingS. pyogenesandS. aureusCas9 “bait” DNA double strand breaks (DSBs), to measure differences in proximal deletions, inversions, and excision circles and their translocation to “prey” genome-wide DSBs generated by CONV (0.08-0.13Gy/s) and FLASH (1x102-5x106Gy/s) dose rates, under varying IR doses and oxygen tensions. Normoxic and physioxic IR exposure in HEK293T cells increased translocations at the cost of decreasing proximal repair but were indistinguishable between CONV and FLASH dose-rates. Although decreased numbers of translocations were recovered as cells transitioned to hypoxic (<2%) conditions, the combined decrease in oxygen tension with IR dose-rate modulation did not reveal significant differences in the level of translocations nor in junction structures, which, for proximal repair, were increased in direct and short microhomologies. We conclude that irrespective of oxygen tension, FLASH IR dose rates produce translocations and junction structures at levels that are indistinguishable from CONV dose rates.
2023-03-29 | GSE227466 | GEO
Project description:Chromosomal translocations result from the joining of DNA double-strand breaks (DSBs) and frequentlycause cancer. However, the steps linking DSB formation to DSB ligation remain undeciphered. Wereport that DNA replication timing (RT) directly regulates lymphomagenicMyctranslocations duringantibody maturation in B cells downstream of DSBs and independently of DSB frequency. Depletion ofminichromosome maintenance complexes alters replication origin activity, decreases translocations,and deregulates global RT. Ablating a single origin atMyccauses an early-to-late RT switch, loss oftranslocations, and reduced proximity with the immunoglobulin heavy chain (Igh) gene, its majortranslocation partner. These phenotypes were reversed by restoring early RT. Disruption of early RT alsoreduced tumorigenic translocations in human leukemic cells. Thus, RT constitutes a general mechanismin translocation biogenesis linking DSB formation to DSB ligation.
2022-09-15 | GSE161818 | GEO
Project description:Purpose: Tumor hypoxia is a major cause of treatment resistance, especially to radiation therapy at conventional dose rate (CONV), and we wanted to assess whether hypoxia does alter tumor sensitivity to FLASH. Methods and materials: We engrafted several tumor types (glioblastoma [GBM], head and neck cancer, and lung adenocarcinoma) subcutaneously in mice to provide a reliable and rigorous way to modulate oxygen supply via vascular clamping or carbogen breathing. We irradiated tumors using a single 20-Gy fraction at either CONV or FLASH, measured oxygen tension, monitored tumor growth, and sampled tumors for bulk RNAseq and pimonidazole analysis. Next, we inhibited glycolysis with trametinib in GBM tumors to enhance FLASH efficacy. Results: Using various subcutaneous tumor models, and in contrast to CONV, FLASH retained antitumor efficacy under acute hypoxia. These findings show that in addition to normal tissue sparing, FLASH could overcome hypoxia-mediated tumor resistance. Follow-up molecular analysis using RNAseq profiling uncovered a FLASH-specific profile in human GBM that involved cell-cycle arrest, decreased ribosomal biogenesis, and a switch from oxidative phosphorylation to glycolysis. Glycolysis inhibition by trametinib enhanced FLASH efficacy in both normal and clamped conditions. Conclusions: These data provide new and specific insights showing the efficacy of FLASH in a radiation-resistant context, proving an additional benefit of FLASH over CONV.
2024-01-24 | GSE223607 | GEO
Project description:Chromosomal translocations result from joining of DNA double-strand breaks (DSBs) and frequently cause cancer. Yet, the steps linking DSB formation to DSB ligation remain undeciphered. We report that DNA replication timing (RT) directly regulates lymphomagenic Myc translocations during antibody maturation in B-cells downstream of DSBs and independently of DSB frequency. Depletion of minichromosome-maintenance (MCM) complexes alters replication origin activity, decreases translocations and abrogates global RT. Ablating a single origin at Myc causes an early-to-late RT switch, loss of translocations and reduced nuclear proximity with a translocation partner locus, phenotypes that were reversed by restoring early RT. Disruption of shared early RT also reduced tumorigenic translocations in human leukemic cells. Thus, RT constitutes a new, unprecedented mechanism in translocation biogenesis linking DSB formation to DSB ligation
2022-09-13 | PXD034446 | Pride
Project description:FLASH, a novel method, was utilized to identify binding sites of RNA-binding proteins (RBPs) with single-nucleotide resolution (Nucleic Acids Res 2020;48:e15). In order to identify HuR target genes in THP-1 macrophages after circARCN1 regulation, we performed FLASH experiments using the anti-HuR antibody on THP-1 macrophages with circARCN1 knockdown or overexpression. The resulting FLASH products were then subjected to RNA sequencing.
2024-06-01 | GSE254370 | GEO
Project description:Single cell sequencing with FLASH-seq of K562 and mESC cells
| PRJEB67543 | ENA
Project description:We have used a combination of RNAi based functional and molecular genomic approaches to investigate in detail two proteins required for the survival of CRC cells. Set1 has 22 samples, 10 siNeg controls, 6 siRNA transfections for FLASH and NUP62 each. Set2 has 67 samples, siNeg controls at timepoint: 10hrs (5), 24hrs (6), 48hrs (6), 72hrs (5), siRNA FLASH at timepoint: 10hrs (8), 24hrs (8), 48hrs (8), 72hrs (8), untreated controls at timepoint: 10hrs (3), 24hrs (3), 48hrs (4), 72hrs (3).
2012-05-06 | E-GEOD-29405 | biostudies-arrayexpress
Project description:Metastasis consists of sequential steps initiated by cancer cells invading from the primary tumor site into neighboring tissues, followed by entry into the circulatory system and completed by extravasation and growth in distal organs. Circulating tumor cells, thus, encounter and adapt to multiple environmental changes during this transition. Epithelial-to-mesenchymal transition (EMT) is a developmental program that consists of loss of epithelial features concomitant with acquisition of mesenchymal features. Activation of EMT in cancer facilitates acquisition of aggressive traits and cancer invasion. EMT plasticity (EMP), the dynamic transition between multiple hybrid states in which cancer cells display both epithelial and mesenchymal phenotypes, confers survival advantages for cancer cells in the constantly changing environment. Therefore, understanding the molecular mechanisms regulating intermediate phenotypic states along the E–M spectrum is critical. Core EMT transcription factors (EMT-TFs), ZEB, SNAI and TWIST families, play an important role in EMT and its plasticity. In the present study we characterize FLASH as a regulator of EMP and multiple EMT-TFs. We demonstrate that loss of FLASH gives rise to a hybrid E/M phenotype with high epithelial scores even in the presence of TGFβ, as determined by computational methods using expression of predetermined sets of epithelial and mesenchymal genes. We demonstrate that FLASH is regulating expression of multiple cell junction proteins with an established role in cancer progression and that its role in EMT is independent of its histone biogenesis role. Further, we show that FLASH expression in cancer lines is inversely correlated with the epithelial score, consistent with its function as a repressor of the epithelial phenotype. Nonetheless, activation of a distinct set of mesenchymal markers concomitant with epithelial markers reveals the complex role of FLASH in EMT and indicates that intermediate E/M states could arise from opposing control by FLASH on different families of EMT-TFs.
2023-12-14 | GSE245621 | GEO
Project description:Hypoxic tumors are sensitive to FLASH radiotherapy
| PRJNA926967 | ENA