scholarly journals Preventing Dr. Jekyll from becoming Mr. Hyde: Is manganese superoxide dismutase the key to prevent radiation-induced neoplastic transformation?

2009 ◽  
Vol 8 (20) ◽  
pp. 1972-1973 ◽  
Author(s):  
Aaron K. Holley ◽  
Daret K. St. Clair
2003 ◽  
Vol 159 (3) ◽  
pp. 361-370 ◽  
Author(s):  
Hongliang Guo ◽  
Jose A. Seixas-Silva ◽  
Michael W. Epperly ◽  
Joan E. Gretton ◽  
Dong M. Shin ◽  
...  

2019 ◽  
Vol 20 (21) ◽  
pp. 5431 ◽  
Author(s):  
Samuela Cataldi ◽  
Antonella Borrelli ◽  
Maria Rachele Ceccarini ◽  
Irina Nakashidze ◽  
Michela Codini ◽  
...  

Studies on the relationship between reactive oxygen species (ROS)/manganese superoxide dismutase (MnSOD) and sphingomyelinase (SMase) are controversial. It has been demonstrated that SMase increases the intracellular ROS level and induces gene expression for MnSOD protein. On the other hand, some authors showed that ROS modulate the activation of SMase. The human recombinant manganese superoxide dismutase (rMnSOD) exerting a radioprotective effect on normal cells, qualifies as a possible pharmaceutical tool to prevent and/or cure damages derived from accidental exposure to ionizing radiation. This study aimed to identify neutral SMase (nSMase) as novel molecule connecting rMnSOD to its radiation protective effects. We used a new, and to this date, unique, experimental model to assess the effect of both radiation and rMnSOD in the brain of mice, within a collaborative project among Italian research groups and the Joint Institute for Nuclear Research, Dubna (Russia). Mice were exposed to a set of minor γ radiation and neutrons and a spectrum of neutrons, simulating the radiation levels to which cosmonauts will be exposed during deep-space, long-term missions. Groups of mice were treated or not-treated (controls) with daily subcutaneous injections of rMnSOD during a period of 10 days. An additional group of mice was also pretreated with rMnSOD for three days before irradiation, as a model for preventive measures. We demonstrate that rMnSOD significantly protects the midbrain cells from radiation-induced damage, inducing a strong upregulation of nSMase gene and protein expression. Pretreatment with rMnSOD before irradiation protects the brain with a value of very high nSMase activity, indicating that high levels of activity might be sufficient to exert the rMnSOD preventive role. In conclusion, the protective effect of rMnSOD from radiation-induced brain damage may require nSMase enzyme.


2003 ◽  
Vol 23 (7) ◽  
pp. 2362-2378 ◽  
Author(s):  
Guozheng Guo ◽  
Yan Yan-Sanders ◽  
Beverly D. Lyn-Cook ◽  
Tieli Wang ◽  
Daniel Tamae ◽  
...  

ABSTRACT Antioxidant enzymes are critical in oxidative stress responses. Radioresistant variants isolated from MCF-7 human carcinoma cells following fractionated ionizing radiation (MCF+FIR cells) or overexpression of manganese superoxide dismutase (MCF+SOD cells) demonstrated dose-modifying factors at 10% isosurvival of 1.8 and 2.3, respectively. MCF+FIR and MCF-7 cells (exposed to single-dose radiation) demonstrated 5- to 10-fold increases in MnSOD activity, mRNA, and immunoreactive protein. Radioresistance in MCF+FIR and MCF+SOD cells was reduced following expression of antisense MnSOD. DNA microarray analysis and immunoblotting identified p21, Myc, 14-3-3 zeta, cyclin A, cyclin B1, and GADD153 as genes constitutively overexpressed (2- to 10-fold) in both MCF+FIR and MCF+SOD cells. Radiation-induced expression of these six genes was suppressed in fibroblasts from Sod2 knockout mice (−/−) as well as in MCF+FIR and MCF+SOD cells expressing antisense MnSOD. Inhibiting NF-κB transcriptional activity in MCF+FIR cells, by using mutant IκBα, inhibited radioresistance as well as reducing steady-state levels of MnSOD, 14-3-3 zeta, GADD153, cyclin A, and cyclin B1 mRNA. In contrast, mutant IκBα was unable to inhibit radioresistance or reduce 14-3-3 zeta, GADD153, cyclin A, and cyclin B1 mRNAs in MCF+SOD cells, where MnSOD overexpression was independent of NF-κB. These results support the hypothesis that NF-κB is capable of regulating the expression of MnSOD, which in turn is capable of increasing the expression of genes that participate in radiation-induced adaptive responses.


2002 ◽  
Vol 157 (5) ◽  
pp. 568-577 ◽  
Author(s):  
Michael W. Epperly ◽  
Christine A. Sikora ◽  
Stacy J. DeFilippi ◽  
Joan A. Gretton ◽  
Qimin Zhan ◽  
...  

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