title: Time-Lapse Monitoring of DNA Damage Colocalized With Particle Tracks in Single Living Cells.
abstract: Understanding the DNA damage and repair induced by hadron therapy (HT) beams is crucial for developing novel strategies to maximize the use of HT beams to treat cancer patients. However, spatiotemporal studies of DNA damage and repair for beam energies relevant to HT have been challenging. We report a technique that enables spatiotemporal measurement of radiation-induced damage in live cells and colocalization of this damage with charged particle tracks over a broad range of clinically relevant beam energies. The technique uses novel fluorescence nuclear track detectors with fluorescence confocal laser scanning microscopy in the beam line to visualize particle track traversals within the subcellular compartments of live cells within seconds after injury.
  
  
  
  We designed and built a portable fluorescence confocal laser scanning microscope for use in the beam path, coated fluorescence nuclear track detectors with fluorescent-tagged live cells (HT1080 expressing enhanced green fluorescent protein tagged to XRCC1, a single-strand break repair protein), placed the entire assembly into a proton therapy beam line, and irradiated the cells with a fluence of ∼1 × 10(6) protons/cm(2).
  
  
  
  We successfully obtained confocal images of proton tracks and foci of DNA single-strand breaks immediately after irradiation.
  
  
  
  This technique represents an innovative method for analyzing biological responses in any HT beam line at energies and dose rates relevant to therapy. It allows precise determination of the number of tracks traversing a subcellular compartment and monitoring the cellular damage therein, and has the potential to measure the linear energy transfer of each track from therapeutic beams.
authors: Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas.
authors: Conor H
authors: CH
authors: McFadden
authors: Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas; Department of Physics and Astronomy, Rice University, Houston, Texas.
authors: Timothy M
authors: TM
authors: Hallacy
authors: Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas; Graduate School of Biomedical Sciences, The University of Texas, Houston, Texas.
authors: David B
authors: DB
authors: Flint
authors: Department of Medical Physics, The Ottawa Hospital Cancer Centre, Ottawa, Ontario, Canada.
authors: Dal A
authors: DA
authors: Granville
authors: Division of Molecular Radiation Biology, Department of Radiation Oncology, University of Texas Southwestern Medical Centre, Dallas, Texas.
authors: Aroumougame
authors: A
authors: Asaithamby
authors: Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas.
authors: Narayan
authors: N
authors: Sahoo
authors: Crystal Growth Division, Landauer, Inc, Stillwater, Oklahoma.
authors: Mark S
authors: MS
authors: Akselrod
authors: Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas; Graduate School of Biomedical Sciences, The University of Texas, Houston, Texas. Electronic address: gsawakuchi@mdanderson.org.
authors: Gabriel O
authors: GO
authors: Sawakuchi
mesh_terms: D045744:Cell Line, Tumor; D058948:Cell Tracking / Q000379:methods; D004249:DNA Damage / Q000502:physiology*; D004273:DNA, Neoplasm / Q000528:radiation effects* / Q000648:ultrastructure; D006801:Humans; D018499:Linear Energy Transfer / Q000235:genetics* / Q000502:physiology / Q000528:radiation effects; D018613:Microscopy, Confocal / Q000379:methods*; D008856:Microscopy, Fluorescence / Q000379:methods; D009374:Neoplasms, Experimental / Q000235:genetics / Q000532:radiotherapy*; D061766:Proton Therapy / Q000379:methods; D011522:Protons; D059008:Time-Lapse Imaging / Q000379:methods*
chemical_list: D004273:DNA, Neoplasm; D011522:Protons