硼替佐米对鼻咽癌细胞的放疗增敏作用及机制

Sensitizing effect and mechanism of bortezomib on radiotherapy of nasopharyngeal carcinoma cells

目的探讨硼替佐米对鼻咽癌细胞株CNE1的放疗增敏作用及机制。方法采用CCK-8法检测不同浓度(0、5、10、15、20、25、30、50、100 nmol/L)的硼替佐米作用于鼻咽癌细胞株CNE1后对细胞增殖能力的影响,计算出IC50,选出适宜的硼替佐米浓度为20 nmol/L;将体外培养的鼻咽癌细胞株CNE1随机分为对照组、单药组(硼替佐米20 nmol/L)、照射组(8 Gy,6 MV X线)及联合组(硼替佐米20 nmol/L+8 Gy X线照射)。流式细胞技术检测各组细胞凋亡率;克隆形成实验检测硼替佐米作用后细胞的放疗敏感性;采用Western blotting法检测硼替佐米作用于鼻咽癌细胞株CNE1后对Rad51、γ组蛋白2A变异体(γ-H2AX)和聚腺苷二磷酸核糖聚合酶(PARP)蛋白表达的影响。结果硼替佐米对CNE1细胞株具有抑制作用,且呈时间剂量依赖性(P均<0.05);联合组细胞凋亡率高于其他3组(P均<0.01);硼替佐米具有放疗增敏作用,放疗增敏比为1.57;与其他3组比较,联合组Rad51表达降低,γ-H2AX、cleaved-PARP蛋白表达升高。结论硼替佐米对鼻咽癌细胞株CNE1有放疗增敏作用,其机制与诱导细胞凋亡和抑制X线照射后细胞DNA损伤的修复相关。

Objective To explore the sensitizing effect and relative mechanism of bortezomib on radiotherapy of nasopharyngeal carcinoma cell line CNE1. Methods The CCK-8 assay was used to detect the inhibition proliferation of bortezomib( 0、5、10、15、20、25、30、50、100 nmol / L) for CNE1 cells of 24 and 48 h,and we calculated the IC50 to choose the suitable concentration,which was 20 nmol / L. Nasopharyngeal carcinoma cell line CNE1 was cultured in vitro and divided into the control group,the bortezomib group,the radiation group( 8 Gy,6 MV X-ray) and the combination group( 20 nmol / L bortezomib + 8 Gy Xray). The apoptosis rate in each group was detected by flow cytometry. Radiosensitivity changes of CNE1 cells treated with bortezomib were detected by colony formation assay. Western blotting was used to detect the protein expression of Rad51,γ-H2 AX and PARP. Results Bortezomib inhibited the growth of CNE1 cells and it was in a dose- and time-dependent manner. The apoptosis rate of the combination group was significantly increased. Bortezomib enhanced the radiosensitivity of nasopharyngeal carcinoma,and the sensitizing enhancement ratio( SER) was 1. 57. The expression levels of cleaved-PARP and γ-H2 AX were increased in the combination group as compared with those of the other three groups,and the Rad51 was decreased. Conclusion Bortezomib enhances the radiosensitivity of nasopharyngeal carcinoma cell line CNE1,whose mechanism may be related with inducing apoptosis and inhibiting the repairing of radiation-induced DNA injuries.