The goal of this investigation is the characterization of the delayed radioprotective effect induced following exposure of cells to non-protein thiols (NPT). The underlying hypothesis is that NPT exposure of cells results in activation of the redox sensitive nuclear transcription factor kappaB (NFkappaB) and enhancement in manganese superoxide dismutase (MnSOD) gene expression followed by elevated intracellular levels of active MnSOD protein. MnSOD is an anti-oxidant protein that can confer protection against oxidative radical species induced by ionizing radiation. The ability of NPT to induce at a later time elevated MnSOD levels results in a delayed radioprotective effect that will have implications in radioprotection in general, and tumor protection in particular. This study focuses on four clinically approved NPT, amifostine, mesna, Nacetylcysteine (NAC), and captopril. These NPT are currently in clinical use, and the potential for their induction of a delayed radioprotective effect in tumors of patients undergoing cancer treatment is a here-tofore unrecognized problem.
Four specific aims are proposed.
Aim 1 seeks to test the hypothesis that NPT over a range of doses will enhance MnSOD gene expression, leading to elevated intracellular levels of active MnSOD protein accompanied by increased catalase and glutathione peroxidase (GPx) activities in cultured tumor and non-tumor cells.
Aim 2 will test the hypothesis that elevated MnSOD activity will result in enhanced radioprotection, especially at 2 Gy.
Aim 3 is focused on testing the hypothesis that either single or multiple exposures of animals to NPT will result in elevated MnSOD gene expression and protein activity in both normal and tumor tissues, the latter grown as pulmonary tumor nodules or solid tumors in the hind legs of animals.
Aim 4 will test the hypothesis that elevated MnSOD activity will result in delayed radioprotection to selected normal and tumor tissues as determined by quantitative survival assays, i.e., spleen colony assay, intestinal microcolony assay, lung colony assay, and the TCD50 assay. Two alternative hypotheses will also be tested. One elevated MnSOD activity can result in anti-oxidant imbalance relating to catalase and GPx activities, resulting in hydrogen peroxide buildup and radiation sensitization. Two, elevation in MnSOD level without a concomitant increase in enzymatic activity can result from nitration of MnSOD by peroxynitrite (ONOO-).

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
5R01CA099005-04
Application #
7059411
Study Section
Radiation Study Section (RAD)
Program Officer
Stone, Helen B
Project Start
2003-07-01
Project End
2008-06-30
Budget Start
2006-07-01
Budget End
2008-06-30
Support Year
4
Fiscal Year
2006
Total Cost
$298,205
Indirect Cost
Name
University of Chicago
Department
Radiation-Diagnostic/Oncology
Type
Schools of Medicine
DUNS #
005421136
City
Chicago
State
IL
Country
United States
Zip Code
60637
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Grdina, David J; Murley, Jeffrey S; Kataoka, Yasushi et al. (2009) Amifostine induces antioxidant enzymatic activities in normal tissues and a transplantable tumor that can affect radiation response. Int J Radiat Oncol Biol Phys 73:886-96
Fu, P; Birukova, A A; Xing, J et al. (2009) Amifostine reduces lung vascular permeability via suppression of inflammatory signalling. Eur Respir J 33:612-24
Murley, Jeffrey S; Nantajit, Danupon; Baker, Kenneth L et al. (2008) Maintenance of manganese superoxide dismutase (SOD2)-mediated delayed radioprotection induced by repeated administration of the free thiol form of amifostine. Radiat Res 169:495-505
Kataoka, Yasushi; Murley, Jeffrey S; Baker, Kenneth L et al. (2007) Relationship between phosphorylated histone H2AX formation and cell survival in human microvascular endothelial cells (HMEC) as a function of ionizing radiation exposure in the presence or absence of thiol-containing drugs. Radiat Res 168:106-14
Kataoka, Yasushi; Bindokas, Vytautas P; Duggan, Ryan C et al. (2006) Flow cytometric analysis of phosphorylated histone H2AX following exposure to ionizing radiation in human microvascular endothelial cells. J Radiat Res (Tokyo) 47:245-57
Murley, Jeffrey S; Kataoka, Yasushi; Weydert, Christine J et al. (2006) Delayed radioprotection by nuclear transcription factor kappaB -mediated induction of manganese superoxide dismutase in human microvascular endothelial cells after exposure to the free radical scavenger WR1065. Free Radic Biol Med 40:1004-16
Murley, Jeffrey S; Kataoka, Yasushi; Cao, Dingcai et al. (2004) Delayed radioprotection by NFkappaB-mediated induction of Sod2 (MnSOD) in SA-NH tumor cells after exposure to clinically used thiol-containing drugs. Radiat Res 162:536-46
Khodarev, Nikolai N; Kataoka, Yasushi; Murley, Jeffrey S et al. (2004) Interaction of amifostine and ionizing radiation on transcriptional patterns of apoptotic genes expressed in human microvascular endothelial cells (HMEC). Int J Radiat Oncol Biol Phys 60:553-63