电离辐射诱导结肠癌细胞自噬以及自噬在辐射中的作用

目的 观察辐射诱导结肠癌SW480细胞发生自噬的情况,以及自噬在辐射中的作用。方法 采用透射电镜观察细胞超微结构,免疫荧光观察自噬泡,蛋白质免疫印迹法检测LC3水平,MTT检测细胞增殖情况,Tanswell小室观察细胞的侵袭,划痕实验观察细胞迁移。结果 重离子与X射线辐射能够诱导SW480细胞发生自噬,且自噬水平随辐射剂量的增加而增加(F=458.526,P<0.05);雷帕霉素(rapamycin, RAPM)能够诱导SW480细胞发生自噬,联合照射时,具有协同作用(F=189.393,P<0.05);氯喹(chloroquine,CQ)能够抑制辐射所诱导的SW480细胞发生的自噬;单纯照射组、照射联合RAPM组细胞的侵袭力、迁移力及活性减弱(F=194.692、629.917、302.903,P<0.05);辐射与CQ联合处理组细胞的侵袭力、迁移力及活性增强(F=194.692、629.917、302.903,P<0.05)。结论 电离辐射可诱导结肠癌SW480细胞发生自噬,自噬对细胞有杀伤作用。

Radiation-induced autophagy in colon cancer cells and its effect in radiation responses

Objective To observe the autophagy induced by heavy ion and X-ray radiations in SW480 cells and its effect in radiation responses. Methods The cellular ultrastructure was observed with a transmission electron microscope (TEM). The autophagy vesicles were labeled by monodansylcadaverin (MDC) fluorescence. The levels of LC3 which were induced by radiation and rapamycin were measured by Western blot assay. Cell proliferation was detected by MTT assay. The invasion of SW480 colon cells was measured with a Transwell. Cell wound healing assay was used to observe the migration of SW480 colon cells. Results Heavy ion and X-ray radiation could induce autophagy in SW480 cells in a dose dependent manner i.e., the autophagy level increased along with irradiation dose (F=458.526, P<0.05), but this induction of autophagy was inhibited by chloroquine. Rapamycin could also induce autophagy in SW480 cells and it had a synergistic effect with irradiation(F=189.393, P<0.05). The abilities of invasion, migration and proliferation of SW480 cells were reduced by irradiation and the combination treatment of irradiation and rapamycin (F=194.692, 629.917, 302.903, P<0.05), but they were enhanced by chloroquine (F=194.692, 629.917, 302.903, P<0.05). Conclusions Ionization radiation causes cell death by inducing autophagy.