title: Conditional radioresistance of Tet-inducible manganese superoxide dismutase bone marrow stromal cell lines.
abstract: Mitochondrial targeted manganese superoxide dismutase is a major antioxidant enzyme, the levels of which modulate the response of cells, tissues and organs to ionizing irradiation. We developed a Tet-regulated MnSOD mouse (MnSOD(tet)) to examine the detailed relationship between cellular MnSOD concentration and radioresistance and carried out in vitro studies using bone marrow culture derived stromal cell lines (mesenchymal stem cells). Homozygous MnSOD(tet/tet) cells had low levels of MnSOD, reduced viability and proliferation, increased radiosensitivity, elevated overall antioxidant stores, and defects in cell proliferation and DNA strand-break repair. Doxycycline (doxy) treatment of MnSOD(tet/tet) cells increased MnSOD levels and radioresistance from ñ of 2.79 ± 1.04 to 8.69 ± 1.09 (P = 0.0060) and normalized other biologic parameters. In contrast, MnSOD(tet/tet) cells showed minimal difference in baseline and radiation induced mRNA and protein levels of TGF-β, Nrf2 and NF-κB and radiation induced cell cycle arrest was not dependent upon MnSOD level. These novel MnSOD(tet/tet) mouse derived cells should be valuable for elucidating several parameters of the oxidative stress response to ionizing radiation.
authors.affiliation: Department of Radiation Oncology, University of Pittsburgh Cancer Institute, Pittsburgh, Pennsylvania 15232, USA.
authors.forename: Michael W
authors.initials: MW
authors.lastname: Epperly
authors.forename: J Richard
authors.initials: JR
authors.lastname: Chaillet
authors.forename: Ronny
authors.initials: R
authors.lastname: Kalash
authors.forename: Ben
authors.initials: B
authors.lastname: Shaffer
authors.forename: Julie
authors.initials: J
authors.lastname: Goff
authors.forename: Darcy
authors.initials: D
authors.lastname: Franicola
authors.forename: Xichen
authors.initials: X
authors.lastname: Zhang
authors.forename: Tracy
authors.initials: T
authors.lastname: Dixon
authors.forename: Frank
authors.initials: F
authors.lastname: Houghton
authors.forename: Hong
authors.initials: H
authors.lastname: Wang
authors.forename: Hebist
authors.initials: H
authors.lastname: Berhane
authors.forename: Cynthia
authors.initials: C
authors.lastname: Romero
authors.forename: Jee-Hong
authors.initials: JH
authors.lastname: Kim
authors.forename: Joel S
authors.initials: JS
authors.lastname: Greenberger
mesh_terms: D000818:Animals; D001853:Bone Marrow; D002453:Cell Cycle / Q000187:drug effects / Q000528:radiation effects; D002460:Cell Line / Q000201:enzymology / Q000528:radiation effects*; D002999:Clone Cells / Q000201:enzymology / Q000528:radiation effects; D003114:Colony-Forming Units Assay; D053960:DNA Breaks / Q000528:radiation effects; D004318:Doxycycline / Q000494:pharmacology; D005260:Female; D005720:Gamma Rays / Q000009:adverse effects*; D005786:Gene Expression Regulation / Q000187:drug effects / Q000235:genetics / Q000528:radiation effects; D005838:Genotype; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008822:Mice, Transgenic; D008928:Mitochondria / Q000201:enzymology; D016297:Mutagenesis, Site-Directed; D051267:NF-E2-Related Factor 2 / Q000096:biosynthesis / Q000235:genetics; D016328:NF-kappa B / Q000096:biosynthesis / Q000235:genetics; D010957:Plasmids / Q000235:genetics; D012333:RNA, Messenger / Q000096:biosynthesis; D011836:Radiation Tolerance / Q000235:genetics*; D060888:Real-Time Polymerase Chain Reaction; D017154:Stromal Cells / Q000201:enzymology / Q000528:radiation effects*; D013482:Superoxide Dismutase / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D016212:Transforming Growth Factor beta / Q000096:biosynthesis / Q000235:genetics; D000099156:Superoxide Dismutase 2
chemical_list: D004318:Doxycycline; D051267:NF-E2-Related Factor 2; D016328:NF-kappa B; D012333:RNA, Messenger; D013482:Superoxide Dismutase; D016212:Transforming Growth Factor beta; D000099156:Superoxide Dismutase 2; C495636:Nfe2l2 protein, mouse