Autophagy Blockage Enhances Radiosensitivity of Osteosarcoma MG-63 Cells In Vitro.

BACKGROUND: Osteosarcoma is the most prevalent malignant neoplasm in children and young adults with a very high propensity for local invasion and early systemic metastases. Radiotherapy has been widely used in metastatic and recurrent osteosarcoma, particularly with chemoresistance.

METHODS: To determine whether autophagy is induced by radiation therapy and contributes to cell death of osteosarcoma, we investigated the influence of autophagy blockage on the radiosensitivity of osteosarcoma MG-63 cells in vitro. Firstly, autophagy in the MG-63 osteosarcoma cells after radiation treatment was determined by quantitative GFP-LC3 analysis and autophagy-related molecules analysis by western blotting. Then the viability and death of cells post-blockage of autophagy was determined by MTT assay and flow cytometry.

RESULTS: It was demonstrated that autophagy was involved in MG-63 cells subject to radiation. Significantly up-regulated autophagic vesicles in MG-63 cells were subject to radiation. The transformation of LC-3 I to LC-3 II and the expression of autophagy-associated molecules were promoted in the radiation-treated MG-63 cells. Moreover, autophagy could ameliorate the cell viability post radiation. On the other hand, the chemical blockage of autophagy by 3MA not only could downregulate the level of autophagy, but also could reduce cell viability and accelerate apoptosis in the radiation-treated MG-63 cells.

CONCLUSIONS: Autophagy was involved in the radiation treatment of MG-63 osteosarcoma cells, and autophagy blockage enhances the radiosensitivity of the osteosarcoma cell line MG-63 in vitro.