C-Myc regulates radiation-induced G2/M cell cycle arrest and cell death in human cervical cancer cells.
OBJECTIVE
The study was conducted to investigate the role of c-Myc in the regulation of ionizing radiation-induced cell cycle arrest and cell death in human cervical cancer cells.


METHODS
Control and c-Myc-silenced Hela cells were collected at different time points after60Co γ-ray radiation. Flow cytometry was used to measure cell cycle distribution and apoptosis. Immunofluorescence was applied to determine the percentage of cells in M phase. Transmission electron microscopy and immunoblotting were used to detect the induction of autophagy after radiation. Immunoblotting was also used to measure the expression levels of apoptosis-related proteins.


RESULTS
In c-Myc-silenced cells, radiation induced delayed but long-lasting G2/M arrest and an abnormal M phase compared with the control. In addition, c-Myc knockdown significantly inhibited apoptotic cell death induced by radiation. Meanwhile, radiation-induced autophagy appeared stronger in c-Myc-silenced cells. Mechanically, we found that Caspase 8 and survivin expression was decreased in c-Myc-silenced Hela-630 cells.


CONCLUSIONS
These data showed that c-Myc serves as a co-regulator in radiation-induced G2/M cell cycle arrest and cell death in human cervical cancer cells.
Department of Radiation Medicine, School of Radiation Medicine and Protection, Medical College of Soochow University, Suzhou, China.|Collaborative Innovation Center of Radiation Medicine, Jiangsu Higher Education Institutions, Suzhou, China.
Fengmei
F
Cui
Department of Pathology, Zhongshan Hospital, Fudan University, Shanghai, China.
Jun
J
Hou
Department of Radiation Medicine, School of Radiation Medicine and Protection, Medical College of Soochow University, Suzhou, China.|Collaborative Innovation Center of Radiation Medicine, Jiangsu Higher Education Institutions, Suzhou, China.
Chengcheng
C
Huang
Department of Radiation Medicine, School of Radiation Medicine and Protection, Medical College of Soochow University, Suzhou, China.|Collaborative Innovation Center of Radiation Medicine, Jiangsu Higher Education Institutions, Suzhou, China.
Xiujin
X
Sun
Department of Radiation Medicine, School of Radiation Medicine and Protection, Medical College of Soochow University, Suzhou, China.|Collaborative Innovation Center of Radiation Medicine, Jiangsu Higher Education Institutions, Suzhou, China.
Yanan
Y
Zeng
Department of Radiation Medicine, School of Radiation Medicine and Protection, Medical College of Soochow University, Suzhou, China.|Collaborative Innovation Center of Radiation Medicine, Jiangsu Higher Education Institutions, Suzhou, China.
Huiying
H
Cheng
Department of Oncology, the First Affiliated Hospital, Medical University of Anhui, Hefei, China.
Hao
H
Wang
Department of Radiotherapy and Oncology, Suzhou Kowloon Hospital, Shanghai Jiao Tong University School of Medicine, Suzhou, China.
Chao
C
Li
D016923:Cell Death; D004268:DNA-Binding Proteins; D005260:Female; D059565:G2 Phase Cell Cycle Checkpoints; D006367:HeLa Cells; D006801:Humans; D014157:Transcription Factors; D002583:Uterine Cervical Neoplasms / Q000532:radiotherapy*
D004268:DNA-Binding Proteins; C116115:MYCBP protein, human; D014157:Transcription Factors
G2/M arrest; apoptosis; autophagy c-Myc; ionizing radiation