A New Class of Molecular Targeted Radioprotectors: GSK-3beta Inhibitors
- Department of Radiation Oncology, Vanderbilt University School of Medicine, Nashville, TN (United States)
- Medical Scientist Training Program, Vanderbilt University School of Medicine, Nashville, TN (United States)
Purpose: Development of new treatments is critical to effective protection against radiation-induced injury. We investigate the potential of developing small-molecule inhibitors of glycogen synthase kinase 3beta (GSK-3beta)-SB216763 or SB415286-as radioprotective agents to attenuate intestinal injury. Methods and Materials: A survival study was done by use of C57BL/6J mice to evaluate the radioprotective effect of GSK-3beta inhibitors. Terminal deoxynucleotidyl transferase dUTP nick end labelling (TUNEL) assay and immunohistochemical staining for Bax and Bcl-2 were used to assess apoptosis in the small intestines of the treated mice. A clonogenic survival study, apoptosis assays (staining with annexin V or 4',6-diamidino-2-phenylindole), and immunoblot analysis of beta-catenin, Bcl-2, Bax, and caspase 3 were done by use of Rat intestinal epithelial cell line IEC-6 cells. Results: Pretreatment with SB415286 significantly improved survival of mice irradiated with 8 and 12 Gy. Mice pretreated with SB216763 or SB415286 showed a significant reduction in TUNEL- and Bax-positive cells and an increase in Bcl-2-positive cells in intestinal crypts at 4 and/or 12 h after radiation with 4 and/or 8 Gy compared with radiation alone. Pretreatment of irradiated IEC-6 cells with GSK-3beta inhibitors significantly increased clonogenic survival compared with cells treated with radiation alone. This increase was due to the attenuation of radiation-induced apoptosis, as shown by annexin V and 4',6-diamidino-2-phenylindole assays, as well as immunoblot analysis of Bcl-2, Bax, and caspase 3. Conclusions: Glycogen synthase kinase 3beta small-molecule inhibitors protect mouse intestine from radiation-induced damage in cell culture and in vivo and improve survival of mice. Molecular mechanisms of this protection involve attenuated radiation-induced apoptosis regulated by Bcl-2, Bax, and caspase 3. Therefore GSK-3beta inhibitors reduce deleterious consequences of intestinal irradiation and thereby improve quality of life during radiation therapy.
- OSTI ID:
- 21372074
- Journal Information:
- International Journal of Radiation Oncology, Biology and Physics, Vol. 76, Issue 2; Other Information: DOI: 10.1016/j.ijrobp.2009.09.024; PII: S0360-3016(09)03220-9; Copyright (c) 2010 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; ISSN 0360-3016
- Country of Publication:
- United States
- Language:
- English
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62 RADIOLOGY AND NUCLEAR MEDICINE
APOPTOSIS
GLYCOGEN
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RADIATION PROTECTION
RADIOPROTECTIVE SUBSTANCES
RADIOTHERAPY
SMALL INTESTINE
STANDARD OF LIVING
ANIMALS
BODY
CARBOHYDRATES
DIGESTIVE SYSTEM
DRUGS
GASTROINTESTINAL TRACT
INTESTINES
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MEDICINE
NUCLEAR MEDICINE
ORGANIC COMPOUNDS
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POLYSACCHARIDES
RADIOLOGY
RESPONSE MODIFYING FACTORS
RODENTS
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