Effect of X-rays on expression of caspase-3 and p53 in EL-4 cells and its biological implications.
OBJECTIVE
To investigate the effect of X-rays on expression of caspase-3 and p53 protein in EL-4 cells and its implications in induction of apoptosis and polyploid cells.


METHODS
Mouse lymphoma cell line (EL-4 cells) was used. Fluorescent staining and flow cytometry analysis were employed for measurement of protein expression, apoptosis, cell cycle, and polyploid cells.


RESULTS
The expression of caspase-3 protein increased significantly at 8 h and 12 h, compared with that of sham-irradiated control (P<0.05, respectively) and the expression of p53 protein increased significantly at 2, 4, 8, 12, and 24 h, compared with that of sham-irradiated control (P<0.05-P<0.01) in EL-4 cells after 4.0 Gy X-irradiation. Apoptosis of EL-4 cells was increased significantly at 2, 4, 8, 12, 24, 48, and 72 h after 4.0 Gy exposure, compared with that of sham-irradiated control (P<0.05-P<0.001). G2 phase cells were increased significantly at 4, 8, 12, 24, 48, and 72 h (P<0.05-P<0.001). However, no marked change in the number of 8 C polyploid cells was found from 2 to 48 h after 4.0 Gy exposure.


CONCLUSIONS
The expressions of caspase-3 and p53 protein in EL-4 cells are induced by X-rays, which might play an important role in the induction of apoptosis, and the molecular pathway for polyploid formation might be p53-independent.
Ju
Gui-Zhi
GZ
Department of Radiation Biology, School of Public Health, Jilin University, Changchun 130021, Jilin, China. jugz@mail.jlu.edu.cn
Shen
Bo
B
Sun
Shi-Long
SL
Yan
Feng-Qin
FQ
Fu
Shi-Bo
SB
D000818:Animals; D053148:Caspase 3 / Q000378:metabolism / Q000528:radiation effects*; D020169:Caspases / Q000378:metabolism / Q000528:radiation effects*; D053471:Caspases, Initiator; D045744:Cell Line, Tumor; D051379:Mice; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism / Q000528:radiation effects*; D014965:X-Rays
D016159:Tumor Suppressor Protein p53; C101136:Casp4 protein, mouse; D053148:Caspase 3; D020169:Caspases; D053471:Caspases, Initiator