目的：探讨细胞角蛋白 13（cytokeratin 13，CK13）对鼻咽癌HNE1细胞放疗敏感性的影响及其作用机制。方法：将 HNE1 细胞分为对照组、anti-CK13#a 组及 anti-CK13#b 组（敲减CK13）、对照组+西罗莫司处理组（100 nmol/L 的西罗莫司处理 1 h）、anti-CK13#a+西罗莫司处理组（100 nmol/L 的西罗莫司处理1 h），经放疗处理（200 cGy/min剂量照射5 min）后，用CCK-8 法检测各组细胞的增殖能力，用流式细胞术检测各组细胞的凋亡率，qPCR 法检测 PI3K/AKT/mTOR 信号通路相关基因PTEN的表达，WB法检测PI3K/AKT/mTOR信号通路相关蛋白的表达。结果：经放疗处理后，与对照组相比，敲减CK13后HNE1细胞增殖能力明显增强（P<0.01），细胞凋亡率明显降低（P<0.01）；细胞中c-caspase-3和γH2AX的表达明显降低（均P<0.01）、p-AKT和p-S6K表达明显升高（P<0.01）、PTEN蛋白表达明显降低（P<0.01）。敲减CK13+西罗莫司（PI3K/AKT/mTOR信号通路抑制剂）处理可以回复敲减CK13导致的细胞增殖能力增强（P<0.05）和细胞凋亡率降低（P<0.01）。结论：敲减CK13通过下调PTEN蛋白水平进而增强PI3K/AKT/mTOR信号通路活性，最终降低HNE1细胞的放疗敏感性。

Objective: To investigate the effect of cytokeratin 13 (CK13) on radio-sensitivity of human nasopharyngeal carcinoma HNE1 cell line and its mechanism. Methods: HNE1 cells were divided into control group, anti-CK13#a group (CK13 knockdown),anti-CK13#b group (CK13 knockdown), control+sirolimus group (100 nmol/L sirolimus treatment for 1 h), and anti-CK13#a +sirolimus group (100 nmol/L sirolimus treatment for 1 h). After irradiation treatment (200 cGy/min irradiation for 5 min), cell proliferation in each group was measured by CCK-8 assay. Cell apoptosis rate in each group was determined by Flow cytometry.Expression of PI3K/AKT/mTOR signaling pathway related PTEN gene was detected by qPCR, and WB was used to detect the expressions of PI3K/AKT/mTOR signaling pathway related proteins. Results: In the case of radiotherapy, as compared with the control group, the proliferation of HNE1 cells after CK13 knockdown was significantly enhanced (P<0.01) while the apoptosis rate was significantly reduced (P<0.01), the contents of caspase-3 and γH2AX as well as the protein lever of PTEN in cells were significantly decreased, while the expressions of p-AKT and p-S6K were significantly increased (all P<0.01). Interestingly,additional treatment with sirolimus (PI3K/AKT/mTOR signaling pathway inhibitor) could rescue the accelerated cell proliferation and decreased cell apoptosis caused by CK13 knockdown (all P<0.05). Conclusion: CK13 knockdown can enhance the activity of PI3K/AKT/mTOR signaling pathway by down-regulating PTEN, and ultimately reduce the radio-sensitivity of nasopharyngeal carcinoma HNE1 cells.

云南省科技厅-昆明医科大学应用基础研究联合专项[No. 2018FE001(-173)]