| Lung cancer is one of the most common malignant tumor, is a serious threat to human health. Radiation therapy is commonly used in clinical treatment. It is very important to increase the radiosensitivity of tumor cells and find the best radiosensitizer. Carboplatin is the chemotherapy drug commonly used in clinic. Therefore, it is experimental subjects to A549 cell lines in this experiment, to study the radiosensitization of carboplatin.Methods1 Cell culture A549 cells are used in all experiments, all the experimental conditions are the temperature 37±0.3℃, relative humidity≥95%, CO2 concentration of 5±0.1% of the cell culture incubator.2 Experimental Methods The rose of proliferation on A549 cells was observed by the MTT assay and growth curve of carboplatin. The clonal proliferation and morphological were observed using A549 cells in different experimental groups by colony forming assay. Cell cycle and cell apoptosis were determined by flow cytometry. Invasion was observed under different experimental conditions by Transwell assay with A549 cells. Results1 Effect of proliferation on A549 cells by carboplatinResults showed that IC50 and IC20 of carboplatin were 13.22,3.29μg/ml on A549 cells by MTT colorimetric assay. The growth curves showed proliferation of A549 cells by 1,3,5μg/ml carboplatin. The concentration closest to the IC20 show it was not cytotoxicity in 3 days. So, this concentration was experimented to radiosensitization by carboplatin.2 Radiosensitivity of A549 cells by carboplatin2.1 Effect of cloning efficiency A549 cells were most sensitive to radiation from parameter of single-hit multi-target model, which were treated in 3 days by carboplatin 3μg/ml, D0=1.41;5μg/ml concentration of carboplatin treated cells, the drug itself on the cells is more cytotoxicity, therefore sensitizing effect is not good, Do =1.42;1μg/ml concentration of carboplatin treated cells, the drug concentration is too low, the effect on radiosensitivity is not good, D0=1.70;Do of the control group is 1.77. Therefore, the concentration closest to the IC2o better reflect the sensitizing effect of radiation sensitizer.2.2 Effect of cell cycle S phase cells were increased on the radiation sensitivity in the cell cycle by carboplatin. Radiation after carboplatin treating compared with the control group decreased 48.03%. S phase cells indicate that the ability of proliferation was decreased by carboplatin and radiation.2.3 Effect of cell apoptosis In the control group, radiation group, treatment group, radiosensitization group, the apoptosis rates were 14.51%,21.15%,19.02%,55.77%. Apoptosis rate of radiosensitization group was 2.84 times than the control group.2.4 Effect of invasion In the control group, radiation group, treatment group, radiosensitization compared with the control group had reduced invasive ability, and is statistically significant. But the invasion of cells radiosensitization group than in the other groups are low, invasion was decreased by 51.97% compared with the control group.3 Morphological changes Physaliphore was observed in radiation after carboplatin treatment group by colony forming assay. This phenomenon was not observed in the control group, radiation group and treatment group. Conclusion1. Carboplatin is concentration-dependent and time-dependent on human lung adenocarcinoma A549 cell proliferation in the range of studied concentration, and it appears a clear dose-response relationship.2. It is negatively correlated with radiation dose and the cloning efficiency of A549 cells, the cloning efficiency of carboplatin combined radiation group was lower than the irradiation group with the same dose.3. Low-dose carboplatin could improve human lung adenocarcinoma A549 cells radiosensitivity, and its mechanism may induce apoptosis.4. Low-dose carboplatin could inhibit the invasion of human lung adenocarcinoma A549 cells.5. It is possible that carboplatin could become an effective radiation sensitizer in the treatment of A549 cells. |
PDF Full Text Request