title: Effects of targeted phosphorylation site mutations in the DNA-PKcs phosphorylation domain on low and high LET radiation sensitivity.
abstract: The present study investigated the effect of targeted mutations in the DNA-dependent protein kinase catalytic subunit and phosphorylation domains on the survival of cells in response to different qualities of ionizing radiation. Mutated Chinese hamster ovary V3 cells were exposed to 500 MeV/nucleon initial energy and 200 keV/μm monoenergetic Fe ions; 290 MeV/nucleon initial energy and average 50 keV/μm spread-out Bragg peak C ions; 70 MeV/nucleon initial energy and 1 keV/μm monoenergetic protons; and 0.663 MeV initial energy and 0.3 keV/μm Cs137γ radiation. The results demonstrated that sensitivity to high linear energy transfer radiation is increased when both S2056 and T2609 clusters each contain a point mutation or multiple mutations are present in either cluster, whereas the phosphoinositide 3 kinase cluster only requires a single mutation to induce the sensitized phenotype of V3 cells. Additionally, the present study demonstrated that sensitivity to DNA cross-linking damage by cisplatin only requires a single mutation in one of the three clusters and that additional point mutations do not increase cell sensitivity.
authors: Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO 80523, USA.
authors: Ian M
authors: IM
authors: Cartwright
authors: Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO 80523, USA.
authors: Justin J
authors: JJ
authors: Bell
authors: Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO 80523, USA.
authors: Junko
authors: J
authors: Maeda
authors: Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO 80523, USA.
authors: Matthew D
authors: MD
authors: Genet
authors: Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO 80523, USA.
authors: Ashley
authors: A
authors: Romero
authors: Department of Radiological Sciences, Ibaraki Prefectural University of Health Sciences, Inashiki, Ibaraki 300-0394, Japan.
authors: Yoshihiro
authors: Y
authors: Fujii
authors: Research Center for Charged Particle Therapy, International Open Laboratory, Inage, Chiba 263-8555, Japan.
authors: Akira
authors: A
authors: Fujimori
authors: Research, Development and Support Center, National Institute of Radiological Sciences, Inage, Chiba 263-8555, Japan.
authors: Hisashi
authors: H
authors: Kitamuta
authors: Research Center for Charged Particle Therapy, International Open Laboratory, Inage, Chiba 263-8555, Japan.
authors: Tadashi
authors: T
authors: Kamada
authors: Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX 75235, USA.
authors: David J
authors: DJ
authors: Chen
authors: Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO 80523, USA.
authors: Takamitsu A
authors: TA
authors: Kato
keywords: DNA-protein kinase catalytic subunit; heavy ions; high linear energy transfer radiation; protons