TY - JOUR
T1 - Effects of radiation on the epidermal growth factor receptor pathway in the heart
AU - Sridharan, Vijayalakshmi
AU - Sharma, Sunil K.
AU - Moros, Eduardo G.
AU - Corry, Peter M.
AU - Tripathi, Preeti
AU - Lieblong, Benjamin J.
AU - Guha, Chandan
AU - Hauer-Jensen, Martin
AU - Boerma, Marjan
N1 - Funding Information:
This work was supported by the National Institutes of Health (CA148679, CA71382) and the American Cancer Society (RSG-10-125-01-CCE).
PY - 2013/7
Y1 - 2013/7
N2 - Purpose: Radiation-induced heart disease (RIHD) is a serious side-effect of thoracic radiotherapy. The epidermal growth factor receptor (EGFR) pathway is essential for the function and survival of cardiomyocytes. Hence, agents that target the EGFR pathway are cardiotoxic. Tocotrienols protect from radiation injury, but may also enhance the therapeutic effects of EGFR pathway inhibitors in cancer treatment. This study investigated the effects of local irradiation on the EGFR pathway in the heart and tests whether tocotrienols may modify radiation-induced changes in this pathway. Methods: Male Sprague-Dawley rats received image-guided localized heart irradiation with 21 Gy. Twenty four hours before irradiation, rats received a single dose of tocotrienol-enriched formulation or vehicle by oral gavage. At time points from 2 h to 9 months after irradiation, left ventricular expression of EGFR pathway mediators was studied. Results: Irradiation caused a decrease in the expression of epidermal growth factor (EGF) and neuregulin-1 (Nrg-1) mRNA from 6 h up to 10 weeks, followed by an upregulation of these ligands and the receptor erythroblastic leukemia viral oncogene homolog (ErbB)4 at 6 months. In addition, the upregulation of Nrg-1 was statistically significant up to 9 months after irradiation. A long-term upregulation of ErbB2 protein did not coincide with changes in transcription or post-translational interaction with the chaperone heat shock protein 90 (HSP90). Pretreatment with tocotrienols prevented radiation-induced changes at 2 weeks. Conclusions: Local heart irradiation causes long-term changes in the EGFR pathway. Studies have to address how radiation may interact with cardiotoxic effects of EGFR inhibitors.
AB - Purpose: Radiation-induced heart disease (RIHD) is a serious side-effect of thoracic radiotherapy. The epidermal growth factor receptor (EGFR) pathway is essential for the function and survival of cardiomyocytes. Hence, agents that target the EGFR pathway are cardiotoxic. Tocotrienols protect from radiation injury, but may also enhance the therapeutic effects of EGFR pathway inhibitors in cancer treatment. This study investigated the effects of local irradiation on the EGFR pathway in the heart and tests whether tocotrienols may modify radiation-induced changes in this pathway. Methods: Male Sprague-Dawley rats received image-guided localized heart irradiation with 21 Gy. Twenty four hours before irradiation, rats received a single dose of tocotrienol-enriched formulation or vehicle by oral gavage. At time points from 2 h to 9 months after irradiation, left ventricular expression of EGFR pathway mediators was studied. Results: Irradiation caused a decrease in the expression of epidermal growth factor (EGF) and neuregulin-1 (Nrg-1) mRNA from 6 h up to 10 weeks, followed by an upregulation of these ligands and the receptor erythroblastic leukemia viral oncogene homolog (ErbB)4 at 6 months. In addition, the upregulation of Nrg-1 was statistically significant up to 9 months after irradiation. A long-term upregulation of ErbB2 protein did not coincide with changes in transcription or post-translational interaction with the chaperone heat shock protein 90 (HSP90). Pretreatment with tocotrienols prevented radiation-induced changes at 2 weeks. Conclusions: Local heart irradiation causes long-term changes in the EGFR pathway. Studies have to address how radiation may interact with cardiotoxic effects of EGFR inhibitors.
KW - Epidermal growth factor receptor pathway
KW - Neuregulin-1
KW - Radiation-induced heart disease
KW - Tocotrienols
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U2 - 10.3109/09553002.2013.782110
DO - 10.3109/09553002.2013.782110
M3 - Article
C2 - 23488537
AN - SCOPUS:84879744076
SN - 0955-3002
VL - 89
SP - 539
EP - 547
JO - International Journal of Radiation Biology
JF - International Journal of Radiation Biology
IS - 7
ER -