Journal of Jilin University Medicine Edition ›› 2015, Vol. 41 ›› Issue (06): 1139-1143.doi: 10.13481/j.1671-587x.20150608

Previous Articles     Next Articles

Effects of ionizing radiation on autophagy and apoptosis in MCF-7 cells with Beclin 1 over-and low-expressions and their regulating mechanisms

ZHANG Jing1, ZHAO Dali2, XIE Zhongwei2, LIU Yanjun3, LI Zhijun1, LI Yan1, GONG Shouliang4, QI Yali1   

  1. 1. Department of Epidemiology, School of Public Health, Beihua University, Jilin 132001, China;
    2. Jilin Province (City) Entry and Exit Inspection and Quarantine Bureau, Jilin 132012, China;
    3. Department of Radiotherapy, People's Hospital in Changchun City, Jilin Province, Changchun 130051, China;
    4. Key Laboratory of Radiobiology, Ministry of Health, School of Public Health, Jilin University, Changchun 130021, China
  • Received:2015-09-09 Published:2016-01-11

Abstract:

Objective To establish the MCF-7 cell models of Beclin 1 over-and low-expressions, and to detect the autophagic and apoptotic changes after 4 Gy irradiation, and to explore their molecular regulation mechanisms. Methods MCF-7,MCF-7+4Gy,MCF-7-Beclin 1+4Gy and MCF-7-Belcin 1 RNAi+4Gy groups were set up. Molecular biology method was used to construct Beclin 1 over-expression vector pcDNA3.1-Beclin 1, and to estabilish the Beclin 1 over-and low-expression cell models. After the cells were irradiated with 4 Gy, the autopahgic cell percentages were measured by fluorescence microscope with MDC staining, the apoptotic cell percentages were measured by FCM with AnnexinⅤ-FITC and PI staining, and the expressions of Beclin1, P53, Bcl-2 and Bax proteins were measured by Western blotting method. Results Compared with MCF-7 group, the autophagic and apoptotic cell percentages in MCF-7+4 Gy, MCF-7 Beclin 1+4 Gy and MCF-7-Beclin 1 RNAi+4 Gy groups were significantly increased (P<0.05 or P<0.001 ), especially in MCF-7 Beclin 1+4 Gy group which was significantly higher than those in MCF-7+4 Gy (P<0.05); while there was significant difference in the necrotic cell percentages between various groups. After 4 Gy irradiation, compared with MCF-7 group, the expression levels of Beclin 1, P53 and Bax proteins in MCF-7+4 Gy and MCF-7-Beclin 1+4 Gy groups were increased, but the expression levels of Bcl-2 protein were decreased, especially in MCF-7-Beclin 1+4 Gy group. Conclusion The MCF-7 cell models of Beclin 1 over-and low-expressions are successfully established, and ionizing radiation could induce the autophagy and apoptosis of MCF-7 cells, which is more obvious in Beclin 1 over-expression MCF-7 cells. Beclin 1 can activate P53, inhibit Bcl-2 and activate Bax,which forms the regulation of autophagy and apoptosis by P53.

Key words: autophagy, aopotosis, ionizing radiation, Beclin 1, P53

CLC Number: 

  • R818