The Influence Of Antophagy Inhibition Contributes To Chemoradiotherapy Sensitization Of Oral Squamous Cell Carcinoma

PURPOSE:To study the role and mechanism of autophagy in the radiotherapy of oral squamous cell carcinoma.And investigating the function of autophagy in chemotherapy and ionizing radiation-induced cell death in oral cancer cells.METHODS:1.Oral cancer cell line CAL-27 and KB were used in this study;2.MTT method were used for cell viability and clongenic survival.3.The LC3-II expression level was detected by laser scanning confocal microscope.4.The expression of Bcclin-1 and LC3 was measured using a Western Blot.5.The percentage of apoptotic were assessed by flow cytometry.6.We used the SPSS 19.0 software to analyze the data,and P <0.05 is a statistically significant difference.RESULTS:1.Regulatory autophagy combined with radiotherapy on oral cancer CAL-27 and KB cell linesUsing CQ、3-MA or 6Gy dose of ionizing radiation to treat CAL-27 and KB cells and detect cell proliferation activity,and the results showed CQ+6Gy and 3-MA+6Gy groups siginificantly decreased cell proliferation activity(P <0.05).Compared with the control group,theapoptotic rate of IR group,CQ + IR group and 3-MA + IR group was significantly higher than that of the control group(P<0.05).Compared with IR group,CQ + IR group and 3-MA + IR group,the apoptotic rate was significantly increased(P<0.05).Immunofluorescence results showed that the average fluorescence intensity of IR group was higher than the other groups anddemonstrated autophagy induction in CAL-27 cells 4h following irradiation at a dose of 6Gy(P <0.05).Western blotting for the autophagosome-associated protein light chain 3(LC3)and Beclin-1 confirmed autophagy induction at multiple time points following irradiation(P <0.05).2.Regulatory autophagy combined with radiotherapy and chemotherapy in oral cancer KB cell lines.3-MA and DDP combined with radiotherapy were used to treat KB cells,which significantly reduced the cell survival rate(P<0.05)compared with radiotherapy and chemotherapy.3-MA addition to chemoradiation(IR+DDP)at 6Gy significantly increase the apoptosis rate in KB cells(P <0.05).CONCLUSIONS:Ionizing radiation induced apoptosis and autophagy in oral cancer cells.Autophagy enhanced the radiotherapy resistance of oral cancer cells.Inhibition of autophagy can improve the killing effect of ionizing radiation on oral cancer cells,and inhibition of autophagy can enhance the chemoradiotherapy sensitivity of oral cancer cells.