Zhuo Zhang, kun Zou, CaigangLiu, Lijuan Zou

Radiotherapy department, the Second AffiliatedHospital of Dalian Medical University , Dalian 116023, China

Objective:To investigate the effect of elemene onthe radiosensitivity of A549 cells and its possible molecular mechanism. Method:The effect on cell radiosensitivity was detected using a colony-formingassay. The protein expressions of DNA-PKcs, Bcl-2, and P53 were detected usingwestern blotting. The correlations between the protein expressions of DNA-PKcsand Bcl-2, and of DNA-PKcs and P53 were analyzed. Result: Elemene had aradiosensitizing effect on A549 cells; the SERD0 and SERDq of 10μg/mL elemenewere 1.54 ± 0.20 and 1.43 ± 0.15, respectively, and were 1.63 ± 0.32 and 1.75 ±0.19, respectively, for 20μg/mL elemene. Compared with radiation only, 10 and20μg/mL elemene combined with radiation significantly reduced the expression ofDNA-PKcs (t=7.52, 8.33, P<0.05), and of Bcl-2 (t=10.74, 11.33, P<0.05),while significantly increasing the expression of P53 protein (t=-9.25, -7.66 P<0.05).There was a negative correlation between the expression of DNA-PKcs and P53 (r=-0.569,P=0.040), and a positive correlation between DNA-PKcs and Bcl-2 (r=0.755,P=0.012). Conclusion: Elemene has a radiosensitizing effect onA549 cells and its underlying molecular mechanism might be related todown-regulation of DNA-PKcs gene expression associated with the DNA DSB repairpathway, and up-regulation of P53 and down-regulation of Bcl-2 gene expressionassociated with the cell apoptosis pathway.

Key Words: Elemene  Radiosensitivity  A549 cells DNA-PKcs