靶向干扰细胞周期检验点激酶2增强5-氟尿嘧啶对鼻咽癌细胞SUNE-1的毒性作用研究

Enhanced sensitivity of nasopharyngeal carcinoma SUNE-1 cells to 5-FU by Chk2 knockdown

目的探讨靶向抑制细胞周期检验点激酶2（Chk2）对5-氟尿嘧啶（5-FU）抗鼻咽癌鳞状上皮细胞SUNE-1的增敏作用。方法根据Chk2基因设计siRNA干扰序列，在mRNA和蛋白水平检测其干扰效果；通过细胞生长曲线观察Chk2siRNA对SUNE-1细胞增殖能力的影响；通过细胞毒性试验检测Chk2siRNA是否影响SUNE-1细胞对代谢类抗肿瘤药5-FU的敏感性；采用AnnexinV／PI双染方法检测细胞凋亡的变化情况。结果所采用的siRNA在mRNA和蛋白水平均显著降低SUNE-1细胞中Chk2表达，验证了该siRNA的干扰效果；Chk2siRNA对SUNE-1细胞增殖能力无显著影响，但能显著增强5-Fu的细胞毒作用（P〈0．05）；细胞凋亡检测结果显示，Chk2siRNA显著增加5-FU引起的SUNE-1细胞凋亡水平。结论尽管Chk2对SUNE-1细胞生存和增殖不发挥关键作用，但在5-Fu引起的细胞损伤中对细胞起保护作用，该作用与其抑制5-FU引起的细胞凋亡有关，因此Chk2可成为在鼻咽癌治疗中增强5-FU的疗效的靶点。

Objective To investigate the chemosensitization of Chk2 inhibition to 5-FU against nasopharyngeal squamous epithelial cell line SUNE-1. Methods Chk2 siRNA was designed according to the mRNA sequence of Chk2, and its effect was confirmed by RT-PCR and Western blotting in SUNE-1 cells. Cell growth assay was evaluated to determine the impact of Chk2 siRNA on the proliferation ability of SUNE-1 cells and MTT assay was used to determine the chemosensitization of Chk2 siRNA to 5-FU. Finally, apoptotic cells was stained with Annexin V/PI and examined by flow cytometry. Results Chk2 siRNA significantly reduced mRNA and protein levels of Chk2 in SUNE-1 cells, which confirmed the knockdown effect of Chk2 siRNA. Cell growth assay showed that Chk2 siRNA did not influence the proliferation of SUNE-1 cells. However, Chk2 knockdown significantly enhanced the cytotoxicity and apoptosis of SUNE-1 cells caused by 5-FU. Conclusion Chk2 hinders the toxic effect of 5-FU on SUNE-1 cells, which can be enhanced by Chk2 inhibition. Therefore, Chk2 can be proposed as a target to increase the effect of chemotherapeutic agent, such as 5-FU, in clinical treatment on nasopharyngeal carcinoma.