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目的:探索抑制Polo样激酶1(Polo-like kinase 1,PLK1)对鼻咽癌(nasopharyngeal carcinoma,NPC)细胞CNE-1和CNE-2辐射敏感性的影响。方法:分别运用siRNA和小分子抑制剂BI2536抑制CNE-1和CNE-2细胞内PLK1的表达或磷酸化,通过MTT法检测抑制PLK1对NPC细胞增殖能力的影响,流式细胞技术检测对细胞周期和凋亡的影响,细胞免疫荧光检测对辐射后DNA损伤位点的影响,克隆形成实验及曲线拟合计算对辐射后细胞放射生物参数和放射增敏比(sensitization enhancement ratio,SER)的影响。结果:与对照组相比,抑制PLK1可以明显抑制NPC细胞增殖,并诱导细胞发生G2-M期阻滞和有丝分裂灾难。抑制NPC细胞PLK1联合射线辐射后,NPC细胞克隆形成能力下降(CNE-1:P<0.05;CNE-2:P<0.05),且随着BI2536浓度的增大克隆形成能力下降更加明显(CNE-1:P<0.05;CNE-2:P<0.05);细胞生存分数明显降低(均P<0.05);核中γ-H2AX位点数目明显增加(P<0.05);细胞凋亡率显著升高(均P<0.05);siR-PLK1转染CNE-1和CNE-2后SER分别为1.1988和1.3198,BI2536处理CNE-1和CNE-2后SER分别为1.5508和1.2028。结论:抑制PLK1可以抑制NPC细胞增殖,诱导发生细胞周期阻滞和有丝分裂灾难,并能显著提高NPC细胞辐射敏感性。
OBJECTIVE: To investigate the effects of PLK1 on CNE-1 and CNE-2 sensitivity in nasopharyngeal carcinoma (NPC) cells. Methods: Inhibition of PLK1 expression and phosphorylation in CNE-1 and CNE-2 cells by siRNA and small molecule inhibitor BI2536 respectively. MTT assay was used to detect the effect of PLK1 on the proliferation of NPC cells. Flow cytometry And apoptosis, the effects of immunofluorescence detection on DNA damage sites after radiation, the effects of colony formation assay and curve fitting on the radiobiological parameters and the sensitization enhancement ratio (SER) of irradiated cells. Results: Compared with the control group, inhibition of PLK1 could significantly inhibit the proliferation of NPC cells and induce G2-M arrest and mitosis. CNE-2: P <0.05). The colony-forming ability of NPC cells decreased with the increase of BI2536 concentration (CNE-1: P < 1: P <0.05; CNE-2: P <0.05); the cell survival score was significantly lower (all P <0.05); the number of γ-H2AX sites in the nucleus was significantly increased (All P <0.05). SER of CNE-1 and CNE-2 transfected with siR-PLK1 was 1.1988 and 1.3198, respectively. SER of BI2536 and CNE-2 was 1.5508 and 1.2028, respectively. CONCLUSION: Inhibition of PLK1 can inhibit the proliferation of NPC cells, induce cell cycle arrest and mitotic catastrophe, and significantly improve the radiosensitivity of NPC cells.