Survivin may enhance DNA double-strand break repair capability by up-regulating Ku70 in human KB cells.
BACKGROUND
Survivin, expressed in almost all types of human malignancies, functions as a key factor in radioresistance primarily by inhibiting apoptosis. This study was conducted to investigate whether survivin plays a role in the DNA repair process in the KB human squamous cell carcinoma cell line.


METHODS
A stable KB cell line overexpressing survivin was established through the use of pIRES2-EGFP vector containing the coding region of survivin. Cells were then irradiated with X-rays and evaluated for DNA double-strand breaks (DSBs) by comet assay and flow cytometry for phospho-histone gammaH2AX. The protein levels of some DSB repair genes were detected by Western blotting analysis.


RESULTS
Comet assay and flow cytometry for phospho-histone gammaH2AX showed that overexpression of survivin resulted in significantly fewer DSBs in irradiated cells. Among the DSB repair genes detected, the protein level of Ku70 was up-regulated in survivin-overexpressing KB cells.


CONCLUSIONS
This finding suggests that survivin may enhance DSB repair capability in KB cells by up-regulating Ku70.
Jiang
Gaofeng
G
Faculty of Preventive Medicine, Medical College, Huangjiahu Campus, Wuhan University of Science and Technology, Wuhan 430065, PR China. jianggaofeng@yahoo.com.cn
Ren
Bo
B
Xu
Lei
L
Song
Shizhen
S
Zhu
Changcai
C
Ye
Fangli
F