Nitroxides as Protectors against Oxidative Stress Summary Nitroxides are proving to have broad utility in a number of disease processes and/or conditions that represent excessive oxidative stress. The fact that nitroxides exert activity over such a range of conditions speaks to the importance of free radical reactions in tissue. Likewise, it is becoming apparent that free radicals are important in normal molecular signaling pathways and related gene expression. In collaborative studies, the effects of chronic administration of Tempol (supplemented in food) of two mouse models that exhibit neurodegeneration and/or neurological damage have been evaluated. Iron regulatory protein 2 knockout mice (IRP2-/-) exhibit age-related neurodegeneration (similar to Parkinsons disease patients). Tempol treatment attenuated the progression of neurodegeneration in IRP2-/- mice. Tempol was also shown to be highly protective in an experimental autoimmune encephalomyelitis (EAE) mouse model. The EAE mouse model is an acute or chronic demyelinating autoimmune disease whose clinical manifestations of paralysis and quadriparesis that closely resemble those observed in Multiple Sclerosis patients. These preliminary data are exciting and may represent a new approach toward treating these diseases. Lastly, we continue to search for the mechanism(s) of how long-term administration of Tempol (in the food or drinking water) results in dramatic weight reduction and a decrease in spontaneous tumor incidence in mice. First, we have initiated studies using an in vitro lipogenesis system (3T3L1 cells) and have found that Tempol inhibits lipogenesis in this model. Further, we have found that in this system that induction of lipogenesis results in a reduction in HIF-1 alpha; whereas, Tempol prevents the reduction and hence the formation of fat globules. Further mechanistic studies will be conducted. Second, we have conducted an extensive gene expression array study evaluating tissue taken from age-matched control mice and mice on Tempol food supplementation for 1 month or 1 year. A number of genes have been identified in Tempol supplemented mice that are differentially up- or down-regulated in liver and brain tissue, including genes associated with glutathione metabolism (up-regulated). Genes associated with fat synthesis and storage were found to be modulated by Tempol. The gene array study suggested that hypoxic related genes were also modulated by Tempol. Finally, Tempol administration also significantly delayed the onset of tumors in Atm and p53 deficient mice and more recently in Fanconis Anemia knockout mice. We have recently found that systemic levels of IGF-1 are decreased in Tempol treated animals, similar to that observed in caloric restricted animals. Additionally in preliminary studies, we have shown that Tempol administration (in the food) decreases pristane-induced plasmocytomas in mice, further suggesting that Tempol may interfere/delay the onset of cancer induction. These studies will hopefully enable us to better understand the complex cellular/molecular mechanisms of nitroxides that trigger responses important in the antioxidant properties of nitroxides as well as those related to weight and the chemopreventive findings.

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Simone, Nicole L; Soule, Benjamin P; Ly, David et al. (2009) Ionizing radiation-induced oxidative stress alters miRNA expression. PLoS One 4:e6377
Ghosh, Manik C; Tong, Wing-Hang; Zhang, Deliang et al. (2008) Tempol-mediated activation of latent iron regulatory protein activity prevents symptoms of neurodegenerative disease in IRP2 knockout mice. Proc Natl Acad Sci U S A 105:12028-33
Soule, Benjamin P; Hyodo, Fuminori; Matsumoto, Ken-Ichiro et al. (2007) The chemistry and biology of nitroxide compounds. Free Radic Biol Med 42:1632-50
Soule, Benjamin P; Hyodo, Fuminori; Matsumoto, Ken-Ichiro et al. (2007) Therapeutic and clinical applications of nitroxide compounds. Antioxid Redox Signal 9:1731-43
Tsai, Mong-Hsun; Cook, John A; Chandramouli, Gadisetti V R et al. (2007) Gene expression profiling of breast, prostate, and glioma cells following single versus fractionated doses of radiation. Cancer Res 67:3845-52
Okajo, Aya; Matsumoto, Ken-ichiro; Mitchell, James B et al. (2006) Competition of nitroxyl contrast agents as an in vivo tissue redox probe: comparison of pharmacokinetics by the bile flow monitoring (BFM) and blood circulating monitoring (BCM) methods using X-band EPR and simulation of decay profiles. Magn Reson Med 56:422-31
Patel, Kinjal; Chen, Yifan; Dennehy, Kathryn et al. (2006) Acute antihypertensive action of nitroxides in the spontaneously hypertensive rat. Am J Physiol Regul Integr Comp Physiol 290:R37-43
Thomas, Douglas D; Ridnour, Lisa A; Espey, Michael Graham et al. (2006) Superoxide fluxes limit nitric oxide-induced signaling. J Biol Chem 281:25984-93
Matsumoto, Ken-Ichiro; Hyodo, Fuminori; Matsumoto, Atsuko et al. (2006) High-resolution mapping of tumor redox status by magnetic resonance imaging using nitroxides as redox-sensitive contrast agents. Clin Cancer Res 12:2455-62
Van Waes, Carter; Chang, Angela A; Lebowitz, Peter F et al. (2005) Inhibition of nuclear factor-kappaB and target genes during combined therapy with proteasome inhibitor bortezomib and reirradiation in patients with recurrent head-and-neck squamous cell carcinoma. Int J Radiat Oncol Biol Phys 63:1400-12

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