TY - JOUR
T1 - A New Class of Molecular Targeted Radioprotectors
T2 - GSK-3β Inhibitors
AU - Thotala, Dinesh K.
AU - Geng, Ling
AU - Dickey, Amy K.
AU - Hallahan, Dennis E.
AU - Yazlovitskaya, Eugenia M.
PY - 2010/2/1
Y1 - 2010/2/1
N2 - 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 3β (GSK-3β)-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-3β 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 β-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-3β 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 3β 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-3β inhibitors reduce deleterious consequences of intestinal irradiation and thereby improve quality of life during radiation therapy.
AB - 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 3β (GSK-3β)-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-3β 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 β-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-3β 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 3β 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-3β inhibitors reduce deleterious consequences of intestinal irradiation and thereby improve quality of life during radiation therapy.
KW - Apoptosis
KW - GSK-inhibitors
KW - Intestinal injury
KW - Ionizing irradiation
KW - Radioprotection
UR - http://www.scopus.com/inward/record.url?scp=73649148033&partnerID=8YFLogxK
U2 - 10.1016/j.ijrobp.2009.09.024
DO - 10.1016/j.ijrobp.2009.09.024
M3 - Article
C2 - 20117291
AN - SCOPUS:73649148033
SN - 0360-3016
VL - 76
SP - 557
EP - 565
JO - International Journal of Radiation Oncology Biology Physics
JF - International Journal of Radiation Oncology Biology Physics
IS - 2
ER -