Serum Amyloid P Inhibits Radiation-induced Mucositis
1
Results: VPA had significantly longer paralysis-free probability compared to the control groups (log rank test p \0.001 for both 38 Gy and 40 Gy). The LD50 for Control group was 36.9 Gy. In the VPA group, we did not reach LD50 with doses that went up to 40 Gy. Conclusions: VPA administered before and during irradiation demonstrates protection from late radiation damage in the rat spinal cord. Author Disclosure: D. Kornguth, None; J. Su, None; X. Li, None; K. Ang, None; S. Blaney, None; C. Lau, None; S. Woo, None. 3177 Serum Amyloid P Inhibits Radiation-induced Mucositis L. A. Murray 1 , M. S. Kramer 1 , B. Watkins 2 , E. Fey 2 , D. P. Hesson 1 , S. T. Sonis 3 1 Promedior, Malvern, PA, 2 Biomodels, Boston, MA, 3 Brigham and Women’s Hospital, Boston, MA Background: Oral mucositis is a common side effect following chemotherapy and radiotherapy. The ensuing injury significantly impairs the patients’ quality of life and can hamper the scheduled course of therapy, thus reducing efficacy of treatment. Oral mu- cositis is characterized by a complex pathoetiology in which induction of a series of biologic pathways within the submucosa com- pliments direct clonogenic epithelial cell death to result in pronounced mucosal ulceration. Fibrotic remodeling of the surrounding tissue often ensues, resulting in a loss of elasticity that produces detrimental functional consequences. Serum amyloid P (SAP) is a serum protein shown previously to reduce experimental models of cardiac and pulmonary fibrosis, in part by reducing the infil- tration of bone marrow-derived collagen I+ cells. Purpose/Objective(s): Here we utilized an established hamster cheek pouch model of radiation-induced mucositis to determine if SAP treatment impacts either the clinical or pathological hallmarks of mucositis. Materials/Methods: Hamsters received a single dose of radiation (40 Gy) to the left everted cheek pouch at Day 0. In the SAP treated group, animals received SAP (2 mg/kg, i.p.) every other day from day 0 - Day 12. Beginning on Day 6, and continuing on alternate days until the completion of the experiment (Day 28), photographs of each cheek pouch were taken. At the end of the experiment, photographs were scored for mucositis severity was by observers blinded to the study, using a validated scoring 6 point scheme ranging from 0 (normal tissue, no mucositis) to 5 (complete ulceration). Results: The SAP treatment attenuated the profile of radiation-induced mucositis by delaying the time of onset, reducing the peak value and enhancing the resolution of the pathology. The peak mucositis score was reduced by approximately 0.5 grade in SAP- treated animals. The percentage of animal days with a score of 3 or greater was 21.7% in the SAP treated group compared to 35% in the saline control group (p = 0.002). At the histological level, SAP also inhibited the extent of tissue remodeling, as determined by trichrome staining of collagen. Conclusions: The SAP treatment significantly attenuated radiation-induced injury, suggesting this may be a useful therapy for the palliation of side effects observed during head & neck cancer treatment. Author Disclosure: L.A. Murray, Promedior, A. Employment; M.S. Kramer, Promedior, A. Employment; B. Watkins, None; E. Fey, None; D.P. Hesson, Promedior, A. Employment; S.T. Sonis, Promedior, F. Consultant/Advisory Board. 3178 Radioprotection of Small Intestines and Bone Marrow by Inhibition of Glycogen Synthase Kinase-3 beta (GSK-3b) D. Thotala, D. Hallahan, E. Yazlovitskaya Vanderbilt University, Nashville, TN Background: Radiation-induced impairments are dose-dependent consequences of cancer therapy. Glycogen Synthase Kinase-3 beta (GSK-3b) has emerged as a key regulator of neuronal, endothelial, hepatocyte, fibroblast, and astrocyte death. We studied GSK-3b inhibitors to determine whether they are suitable radioprotectors in small intestines and bone marrow. Purpose/Objective(s): Development of new treatments is critical to effective protection against radiation-induced injury. The physiopathological aspects of normal tissue toxicity have been widely explored; however, none of these descriptive findings has led to the development of effective therapeutic strategies. Our studies have focused on the radioprotective effects of inhibition of GSK-3b. In the earlier study we have shown that small molecule inhibitors of GSK-3b protect hippocampal neurons from ra- diation-induced apoptosis. Extending our study here we show protective effect of GSK-3b inhibitors in small intestines and bone marrow of irradiated mouse models. Materials/Methods: Ten-week-old C57BL6 mice were treated with DMSO or 1.0 mg/kg SB415286 intraperitoneally for 3 con- secutive days followed by a single dose of 4, 8, or 15 Gy of whole body radiation. The femurs from treated mice were fixed in 10% paraformaldehyde and decalcified in 8% hydrochloric acid/formic acid (1:1). The proximal jejunum of the small intestine was also fixed in 10% paraformaldehyde. The decalcified femurs and the jejunum were embedded in paraffin wax using standard techniques. The four micron femur and intestine sections were either stained using TUNEL kit or with hematoxylin. Apoptosis was evaluated by comparing the average number of TPC (TUNEL positive cells) per HPF. Results: Mice pretreated with SB415286 prior irradiation showed significantly less TUNEL-positive cells ( \4 and 8 TPC for 8 Gy; \15 and 10 TPC for 15 Gy; for 4 and 12 h, respectively) as compared to irradiated animals (6 and 15 TPC for 8 Gy; 26 and 28 TPC for 15 Gy; for 4 and 12 h, respectively), indicating possible radioprotective effect of GSK-3b inhibitors from radiation-in- duced damage of gastrointestinal tract. According to the cell position in mice small intestine crypt, the majority of the affected cells are stem cells. Additionally, density of the bone marrow cells in the cavity of the femur from mice treated with SB415286 prior to radiation was significantly higher as compared to mice treated with radiation alone. Conclusions: Our observations suggest the protective effect of GSK-3b inhibition from radiation-induced death in gastrointestinal tract and bone marrow. We propose that small molecule inhibitors of GSK-3b could have a therapeutic role in protecting from radiation-induced injury. Author Disclosure: D. Thotala, None; D. Hallahan, None; E. Yazlovitskaya, None. S698 I. J. Radiation Oncology d Biology d Physics Volume 72, Number 1, Supplement, 2008
Transcript of Serum Amyloid P Inhibits Radiation-induced Mucositis
S698 I. J. Radiation Oncology d Biology d Physics Volume 72, Number 1, Supplement, 2008
Results: VPA had significantly longer paralysis-free probability compared to the control groups (log rank test p \0.001 for both38 Gy and 40 Gy). The LD50 for Control group was 36.9 Gy. In the VPA group, we did not reach LD50 with doses that went up to40 Gy.
Conclusions: VPA administered before and during irradiation demonstrates protection from late radiation damage in the rat spinalcord.
Author Disclosure: D. Kornguth, None; J. Su, None; X. Li, None; K. Ang, None; S. Blaney, None; C. Lau, None; S. Woo, None.
3177 Serum Amyloid P Inhibits Radiation-induced Mucositis
L. A. Murray1, M. S. Kramer1, B. Watkins2, E. Fey2, D. P. Hesson1, S. T. Sonis3
1Promedior, Malvern, PA, 2Biomodels, Boston, MA, 3Brigham and Women’s Hospital, Boston, MA
Background: Oral mucositis is a common side effect following chemotherapy and radiotherapy. The ensuing injury significantlyimpairs the patients’ quality of life and can hamper the scheduled course of therapy, thus reducing efficacy of treatment. Oral mu-cositis is characterized by a complex pathoetiology in which induction of a series of biologic pathways within the submucosa com-pliments direct clonogenic epithelial cell death to result in pronounced mucosal ulceration. Fibrotic remodeling of the surroundingtissue often ensues, resulting in a loss of elasticity that produces detrimental functional consequences. Serum amyloid P (SAP) isa serum protein shown previously to reduce experimental models of cardiac and pulmonary fibrosis, in part by reducing the infil-tration of bone marrow-derived collagen I+ cells.
Purpose/Objective(s): Here we utilized an established hamster cheek pouch model of radiation-induced mucositis to determine ifSAP treatment impacts either the clinical or pathological hallmarks of mucositis.
Materials/Methods: Hamsters received a single dose of radiation (40 Gy) to the left everted cheek pouch at Day 0. In the SAPtreated group, animals received SAP (2 mg/kg, i.p.) every other day from day 0 - Day 12. Beginning on Day 6, and continuing onalternate days until the completion of the experiment (Day 28), photographs of each cheek pouch were taken. At the end of theexperiment, photographs were scored for mucositis severity was by observers blinded to the study, using a validated scoring 6 pointscheme ranging from 0 (normal tissue, no mucositis) to 5 (complete ulceration).
Results: The SAP treatment attenuated the profile of radiation-induced mucositis by delaying the time of onset, reducing the peakvalue and enhancing the resolution of the pathology. The peak mucositis score was reduced by approximately 0.5 grade in SAP-treated animals. The percentage of animal days with a score of 3 or greater was 21.7% in the SAP treated group compared to 35% inthe saline control group (p = 0.002). At the histological level, SAP also inhibited the extent of tissue remodeling, as determined bytrichrome staining of collagen.
Conclusions: The SAP treatment significantly attenuated radiation-induced injury, suggesting this may be a useful therapy for thepalliation of side effects observed during head & neck cancer treatment.
Author Disclosure: L.A. Murray, Promedior, A. Employment; M.S. Kramer, Promedior, A. Employment; B. Watkins, None; E.Fey, None; D.P. Hesson, Promedior, A. Employment; S.T. Sonis, Promedior, F. Consultant/Advisory Board.
3178 Radioprotection of Small Intestines and Bone Marrow by Inhibition of Glycogen Synthase Kinase-3 beta
(GSK-3b)D. Thotala, D. Hallahan, E. Yazlovitskaya
Vanderbilt University, Nashville, TN
Background: Radiation-induced impairments are dose-dependent consequences of cancer therapy. Glycogen Synthase Kinase-3beta (GSK-3b) has emerged as a key regulator of neuronal, endothelial, hepatocyte, fibroblast, and astrocyte death. We studiedGSK-3b inhibitors to determine whether they are suitable radioprotectors in small intestines and bone marrow.
Purpose/Objective(s): Development of new treatments is critical to effective protection against radiation-induced injury. Thephysiopathological aspects of normal tissue toxicity have been widely explored; however, none of these descriptive findingshas led to the development of effective therapeutic strategies. Our studies have focused on the radioprotective effects of inhibitionof GSK-3b. In the earlier study we have shown that small molecule inhibitors of GSK-3b protect hippocampal neurons from ra-diation-induced apoptosis. Extending our study here we show protective effect of GSK-3b inhibitors in small intestines and bonemarrow of irradiated mouse models.
Materials/Methods: Ten-week-old C57BL6 mice were treated with DMSO or 1.0 mg/kg SB415286 intraperitoneally for 3 con-secutive days followed by a single dose of 4, 8, or 15 Gy of whole body radiation. The femurs from treated mice were fixed in 10%paraformaldehyde and decalcified in 8% hydrochloric acid/formic acid (1:1). The proximal jejunum of the small intestine was alsofixed in 10% paraformaldehyde. The decalcified femurs and the jejunum were embedded in paraffin wax using standard techniques.The four micron femur and intestine sections were either stained using TUNEL kit or with hematoxylin. Apoptosis was evaluatedby comparing the average number of TPC (TUNEL positive cells) per HPF.
Results: Mice pretreated with SB415286 prior irradiation showed significantly less TUNEL-positive cells (\4 and 8 TPC for 8 Gy;\15 and 10 TPC for 15 Gy; for 4 and 12 h, respectively) as compared to irradiated animals (�6 and 15 TPC for 8 Gy;�26 and 28TPC for 15 Gy; for 4 and 12 h, respectively), indicating possible radioprotective effect of GSK-3b inhibitors from radiation-in-duced damage of gastrointestinal tract. According to the cell position in mice small intestine crypt, the majority of the affected cellsare stem cells. Additionally, density of the bone marrow cells in the cavity of the femur from mice treated with SB415286 prior toradiation was significantly higher as compared to mice treated with radiation alone.
Conclusions: Our observations suggest the protective effect of GSK-3b inhibition from radiation-induced death in gastrointestinaltract and bone marrow. We propose that small molecule inhibitors of GSK-3b could have a therapeutic role in protecting fromradiation-induced injury.
Author Disclosure: D. Thotala, None; D. Hallahan, None; E. Yazlovitskaya, None.
