E1A基因通过抑制NF-κB信号通路增加鼻咽癌细胞放射敏感性实验研究

目的 探讨E1A基因对人鼻咽癌细胞放射敏感性的影响及其可能机制。方法 通过腺病毒载体介导,将E1A基因转染至鼻咽癌CNE-2R细胞,采用RT-PCR鉴定E1A基因的表达;分别给予未转染组(PBS组)、转染空载体Ad-β-gal组(Ad-β-gal组)和转染E1A组(Ad-E1A组)的CNE-2R细胞0、2、4、6、8 Gy照射,应用克隆形成实验检测各组CNE-2R细胞放射敏感性的变化;流式细胞术检测各组细胞的凋亡;蛋白印迹法检测各组细胞NF-κB、CK2α、Bcl-2及Cleaved caspase-3蛋白的表达。结果 RT-PCR确认E1A基因已整合到CNE-2R细胞中且稳定表达;Ad-E1A组CNE-2R细胞克隆形成率明显少于PBS和Ad-β-gal组的克隆形成率,Ad-E1A组CNE-2R细胞SF2为0.217小于 PBS组和Ad-β-gal组的0.602和0.585(P<0.05),Ad-E1A组α/β值为24.68大于PBS组和Ad-β-gal组的5.268和5.132(P<0.05);流式细胞术显示单独放射可促进CNE-2R细胞的凋亡,当与E1A基因联合使用时,细胞凋亡率明显增加(P<0.05);蛋白印迹法显示E1A基因可下调NF-κB/P65、CK2α、Bcl-2和上调Cleaved caspase-3的表达。结论 E1A基因可以通过抑制CK2的表达阻断NF-κB信号通路以及促进细胞凋亡,来提高鼻咽癌细胞对放射的敏感性。

Effect of E1A gene on radiosensitivity of human nasopharyngeal carcinoma cells and its possible mechanism

Objective To investigate the effect of E1A gene on the radiosensitivity of human nasopharyngeal carcinoma cells and its possible mechanism. Methods The E1A gene was transfected into nasopharyngeal carcinoma CNE-2R cells by adenovirus vector. The expression of E1A gene was detected by RT-PCR. Untransfected CNE-2R cells(PBS group)and CNE-2R cells transfected with empty vector Ad-β-gal(Ad-β-gal group)and E1A(Ad-E1A group)were given 0 Gy,2 Gy,4 Gy,6 Gy,8 Gy 6 MV X-ray irradiation. The changes in radiosensitivity of CNE-2R cells were determined by colony-forming assay. Flow cytometry was used to analyze cell apoptosis in each group. The expression of NF-κB, CK2α, Bcl-2, and cleaved caspase-3 was measured by Western blot. Results RT-PCR confirmed that the E1A gene was transfected into CNE-2R cells and stably expressed. The Ad-E1A group had a significantly lower plating efficiency than the PBS group and the Ad-β-gal group(P<0.05). The Ad-E1A group had significantly lower cell survival rate at 2 Gy irradiation than the PBS group and the Ad-β-gal group(0.217 vs. 0.602, P<0.05;0.217 vs. 0.585, P<0.05). The Ad-E1A group had a significantly higher α/β value than the PBS group and the Ad-β-gal group(24.680 vs. 5.268, P<0.05;24.680 vs. 5.132, P<0.05). Flow cytometry results showed that irradiation alone could promote the apoptosis of CNE-2R cells,when combined with E1A gene,the apoptosis rate was significantly increased(P<0.05). Western blot results showed that E1A gene down-regulated the expression of NF-κB/p65,CK2α,and Bcl-2 and up-regulated the expression of cleaved caspase-3. Conclusions E1A gene can enhance the radiosensitivity of nasopharyngeal carcinoma cells by inhibiting the expression of CK2 to block the NF-κB signaling pathway and promoting cell apoptosis.