Normal-Tissue Radioprotection by Overexpression of the Copper-Zinc and Manganese Superoxide Dismutase Genes

作者：Veldwijk Marlon R; Herskind Carsten; Sellner Leopold; Radujkovic Aleksandar; Laufs Stephanie; Fruehauf Stefan; Zeller W Jens; Wenz Frederik^*

来源：Strahlentherapie und Onkologie, 2009, 185(8): 517-523.

DOI：10.1007/s00066-009-1973-0

• Superoxide dismutase (SOD)
• Fibroblasts
• Radioprotection
• Adeno-associated virus
• Gene transfer

Background and Purpose: Protection of normal tissue against radiation-induced damage may increase the therapeutic ratio of radiotherapy. A promising strategy for testing this approach is gene therapy-mediated overexpression of the copper-zinc (CuZnSOD) or manganese superoxide dismutase (MnSOD) using recombinant adeno-associated viral (rAAV2) vectors. The purpose of this study was to test the modulating effects of the SOD genes on human primary Lung fibroblasts (HPLF) after irradiation.
Material and Methods: HPLF were transduced with rAAV2 vectors containing cDNA for the CuZnSOD, MnSOD or a control gene. The cells were irradiated (1-6 Gy), and gene transfer efficiency, apoptosis, protein expression/activity, and radiosensitivity measured by the colony-forming assay determined.
Results: After transduction, 90.0% +/- 6.4% of the cells expressed the transgene. A significant fivefold overexpression of both SOD was confirmed by an SOD activity assay (control: 21.1 +/- 12.6, CuZnSOD: 95.1 +/- 17.1, MnSOD: 108.5 +/- 36.0 U SOD/mg protein) and immunohistochemistry. CuZnSOD and MnSOD overexpression resulted in a significant radioprotection of HPLF compared to controls (surviving fraction [SF] ratio SOD/control > 1): CuZnSOD: 1.18-fold (95% confidence interval [CI]: 1.06-1.32; p = 0.005), MnSOD: 1.23-fold (95% CI: 1.07-1.43; p = 0.01).
Conclusion: Overexpression of CuZnSOD and MnSOD in HPLF mediated an increase in clonogenic survival after irradiation compared to controls. In previous works, a Lack of radioprotection in SOD-overexpressing tumor cells was observed. Therefore, the present results suggest that rAAV2 vectors are promising tools for the delivery of radioprotective genes in normal tissue.

• 出版日期2009-8