细胞角蛋白13通过PTEN抑制PI3K/AKT/mTOR通路增强鼻咽癌HNE1细胞放疗敏感性

Cytokeratin 13 promotes the radio-sensitivity of nasopharyngeal carcinoma HNE1 cells by inhibiting the PI3K/AKT/mTOR pathway via PTEN

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 c Gy/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,q PCR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 γH2 AX as well as the protein lever of PTEN in cells were significantly decreased, while the expressions of p-AKT and p-S6 K 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.