ABSTRACT
@#[Abstract] 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.