Peng Gao1,2, Fengjin Hao3, Xiu Dong4, Yan Qiu1,2. 1. Nuclear Medicine Department, Cancer Hospital of China Medical University No. 44 Xiaoheyan Road, Dadong District, Shenyang 110042, Liaoning Province, P. R. China. 2. Nuclear Medicine Department, Liaoning Cancer Hospital and Institute No. 44 Xiaoheyan Road, Dadong District, Shenyang 110042, Liaoning Province, P. R. China. 3. Department of Biochemistry and Molecular Biology, China Medical University Shenyang 110122, Liaoning, P. R. China. 4. School of Preclinical Medicine, Liaoning University of Traditional Chinese Medicine 79 Chong Shan Dong Lu, Huanggu District, Shenyang 110847, Liaoning, P. R. China.
Abstract
BACKGROUND/ OBJECTIVES: Thyroid cancer (TC), especially primary squamous cell carcinoma (SCC), is an aggressive malignant tumor which usually resists radiotherapy (RT). We wanted to understand the mechanism of incomplete response of RT in TC cells. METHODS: SCC cell line SW579 cells were exposed to X-rays. Apoptosis and autophagy were measured by FACS; 3MA, inhibitor of autophagy, and Beclin-1 siRNA were used to investigate the effect of autophagy on radiation-induced TC cell apoptosis. RESULTS: RT could induce TC cell apoptosis through death receptor as well as mitochondrial pathway. Radiotherapy also induces autophagy and increases expression of autophagy-associated proteins Beclin-1 and LC3. Moreover, inhibition of autophagy by 3MA and Beclin-1 siRNA enhanced radiation-induced apoptosis, through up-regulation of the expression of p53. CONCLUSION: RT-induced autophagy resists apoptosis by the p53 pathway and an incomplete response to RT may be associated with autophagy in TC patients. IJCEP
BACKGROUND/ OBJECTIVES:Thyroid cancer (TC), especially primary squamous cell carcinoma (SCC), is an aggressive malignant tumor which usually resists radiotherapy (RT). We wanted to understand the mechanism of incomplete response of RT in TC cells. METHODS:SCC cell line SW579 cells were exposed to X-rays. Apoptosis and autophagy were measured by FACS; 3MA, inhibitor of autophagy, and Beclin-1 siRNA were used to investigate the effect of autophagy on radiation-induced TC cell apoptosis. RESULTS: RT could induce TC cell apoptosis through death receptor as well as mitochondrial pathway. Radiotherapy also induces autophagy and increases expression of autophagy-associated proteins Beclin-1 and LC3. Moreover, inhibition of autophagy by 3MA and Beclin-1 siRNA enhanced radiation-induced apoptosis, through up-regulation of the expression of p53. CONCLUSION: RT-induced autophagy resists apoptosis by the p53 pathway and an incomplete response to RT may be associated with autophagy in TCpatients. IJCEP
Authors: V H de Almeida; A C de Melo; D D Meira; A C Pires; A Nogueira-Rodrigues; H K Pimenta-Inada; F G Alves; G Moralez; L S Thiago; C G Ferreira; C Sternberg Journal: Braz J Med Biol Res Date: 2017-11-13 Impact factor: 2.590