Objective To investigate the radiation-sensitizing effects of Ku80 silencing by siRNA interference for A549 lung cancer cells. Methods The sequences of Ku80 siRNA and negative siRNA were chemically synthesized and transfected into A549 lung cancer cells by lipofectamine. RT-PCR and Western bolt analysis were used to determine Ku80 gene expression. The transfected cells in culture dishes were irradiated with X ray at doses of 2 Gy, 4 Gy, 6 Gy, 8 Gy, 10 Gy, respectively. Once all treatments were completed, the cells were processed with the colony formation assay. Results RT-PCR detection showed that Ku80 mRNA levels in A549 lung cancer cells were reduced after transfected with Ku80 siRNA at 24 h, 48 h and 72 h time points. Western blot analysis showed that Ku80 protein content decreased at 48 h and 72 h time points compared with the control group ( P lt; 0. 05 ) . Cloning formation assay indicated that radiosensitivity of A549 lung cancer cells was enhanced after transfected with Ku80 siRNA. Conclusion Ku80 siRNA can effectively inhibit Ku80 gene expression of A549 lung cancer cells, and therefore enhance its radiosensitivity.
Objective Non-small cell lung cancer ( NSCLC) cells are relatively resistant to chemotherapy, and the outcomes are not always satisfactory. This study was designed to explore the relationship between the content of Ku80 protein of human lung cancer cells and their sensitivity to cisplatin.Methods The lung cancer cells isolated frommalignant pleural effusion samples frompatients with primary lung cancer were cultured in vitro. The sensitivity to cisplatin was tested with the method of CCK-8 expressed as half maximal inhibitory concentration ( IC50 ) . The relative content of Ku80 protein was determined by Western blot. The correlation between sensitivity to cisplatin of lung cancer cells and the relative content of Ku80 protein was analyzed. Results The IC50 of NSCLC group was significantly higher than that of SCLCgroup [ ( 4. 40 ±3. 39) mg/L vs. ( 1. 02 ±0. 54) mg/L, P lt; 0. 001] . The relative content of Ku80 protein of NSCLC group was statistically higher than that of SCLC group [ ( 0. 80 ±0. 45) vs. ( 0. 48 ±0. 25) , P lt;0. 05] . The correlation coefficient between content of Ku80 protein and IC50 was 0. 618 ( P lt; 0. 001) .Conclusions The content of Ku80 protein of NSCLC patients is higher than that of SCLC patients. Itmay be one of the mechanisms contributing to chemotherapeutic resistance of NSCLC. There is a negative relationship between Ku80 protein content of cancer cells and their sensitivity to cisplatin suggesting that the content of Ku80 protein may be served as a candidate index for predicting sensitivity of lung cancer cells to cisplatin.