Abstract: Objective: To determine effect of inhibiting of BAG-1 gene expression on radiosensitivity of melanoma B16F10 cells and explore the mechanism. Methods: B16F10 cells were divided into three groups: control group, NC-shRNA group and BAG-1-shRNA group. Medical linear accelerator irradiation and clone counting method were used to calculate the clone formation rate and survival fraction, and the cell survival curve was delineated. The apoptosis rates were detected by flow cytometry. The expression level of apoptosis-related proteins Caspase 3, 8, 9, and c-PARP in melanoma cells were detected by Western blot. Results: After X-ray 8Gy dose irradiation, the survival rates of cells in the control group, NC-shRNA group and BAG-1-shRNA group linear were 1.9%, 1.75%, 0.32% and the apoptosis rate were 7.1%, 9.2% and 25.3% respectively, with significant differences (P<0.05). The levels of c-PARP, Caspase 3, 8, 9 were 0.36, 0.37，0.35 and 0.30 respectively, which were higher than those in the control group and NC-shRNA group, with significant differences (P<0.05). Conclusion: RNA interference of BAG-1 gene expression can significantly increase the sensitivity of melanoma cells to X-ray radiation, which may be associated with accelerating cells apoptosis.

Key words: melanoma, BAG-1, RNA interference, radiosensitizing effect, apoptosis