OBJECTIVE: To study the relationship between the radiotherapy resistance and autophagy. To provide a theoretiacal basis for drugs that regulate autophagy to improve radiotherapy sensitivity. METHOD: Flow cytometry (FCM) was performed to analyze the distribution of the cell cycle of CNE2 and CNE2/DDP cells under the action of X radiation. The expression of autopagy-specific gene Beclin1 and microtubule-associated protein light chain 3β (MAPLC3β) in CNE2 and CNE2/DDP cells was determined by real time PCR and Immumofluorescence staining. RESULT: CNE2/DDP and their parental CNE2 cells produced the G2-M phase arrest under the action of X radiation. With the radiation dose increasing,The cells which in the G2-M phase were more and more (P<0. 05). The G2-M phase arrest in CNE2/DDP cells was more obvious than in CNE2 cells (P<0. 05). The expression of Beclin1 and MAPLC3β in CNE2 and CNE2/DDP cells increased under the action of X radiation. What's more, the raise was more and more obvious with the increase of the irradiation dose(P<0. 05). The expression levels of Beclin1 and MAPLC3β in CNE2/DDP was lower than that in CNE2 cells (P<0. 05). CONCLUSION Autophagic cell death may be the one manner of death in nasopharyngeal carcinoma CNE2 and CNE2/DDP cells under the action of X radiation. The radiation resistance of CNE2/DDP cells may be related to the low expression of autophagy-related genes.
Apoptosis Regulatory Proteins ; genetics ; Autophagy ; Beclin-1 ; Carcinoma ; Cell Cycle ; Cell Line, Tumor ; radiation effects ; Dose-Response Relationship, Radiation ; Humans ; Membrane Proteins ; genetics ; Microtubule-Associated Proteins ; genetics ; Nasopharyngeal Carcinoma ; Nasopharyngeal Neoplasms ; genetics ; Radiation Tolerance ; X-Rays