Heavy Ion And X-ray Induced Autophagy In Colon Cancer Cells And A Preliminary Study On The Role Of Autophagy In Radiotherap

Objective:To observe the autophagy situation induced by heavy ion and X ray radiation in SW480cells, and the role of autophagy plays in radiotherapy.Methods1. The autophagy vesicles were detected by monodansylcadaverin (MDC) fluorescence.2. Autophagy level.apoptosis level and cell cycle were detected using flow cytometry.3. The ultrastructure of cells was observed using transmission electron microscope (TEM).4. Western blotting was used to detect the expression of autophagy related protein LC3.5. The invasion of colon cells was measured by Transwell chamber.6. Cell wound healing assay was used to observe the migration of colon cells.7.Cell activity was measured by MTT.Results1. Heavy ion and X-ray radiation could induce autophagy in SW480cells, and autophagy in a dose dependent manner, which increased with the increase of treatment dose level (P<0.05). Compared with the X-ray, the level of LC3â…¡/LC3I induced by heavy ion was higher in SW480cells.2. Rapamycin induced autophagy in SW480cells, combined with irradiation treatment, there was a synergistic effect3. Chloroquine could inhibit autophagy in SW480cells.4. The number of SW480cells moving into the second floor was decreased in radiation treatment group, radiation and rapamycin combined treatment group (P<0.01),while the migration was also decreased (P<0.05). The number of SW480moving into the second floor was increased in radiation and chloroquine combined treatment group (P<0.01).while the migration was also increased (P<0.05) 5. Cell activity was decreased in the radiation treatment group, radiation and rapamycin combined treatment group. Compared with the radiation treatment group, cell activity was increased in radiation and chloroquine combined treatment group.Conclusions1.The radiation can induce autophagy in SW480cells, and with the increase of autophagy, both of the invasion and migration of SW480cells are decline, and cell viability is also decine. It is suggested that autophagy can kill SW480cells.2.Rapamycin can enhance the radiosensitivity of SW480cells, and chloroquine reduces the radiation sensitivity of SW480cells.3.Compared with the X-ray radiation,the autophagy induced by heavy ion radiation is significantly stronger.Compared with the X-ray radiation group, cell invasion and migration abil-ity is weaker,and cell activity is lower in heavy ion radiation group, suggesting that the heavy ion on the cell killing effect is stronger than the x-ray.