| Objective: To observe the effect of salubrinal regulate endoplasmic reticulum stress(ERS)signaling pathway NF-κB–HIF-1α activation in the human oral squamous carcinoma cells(OSCC)and to detect the expression of apoptotic marker protein cleaved PARP.To explore salubrinal regulate in OSCC radiosensitivity and decect the mechanism.Methods: Radioresistant KBR was constructed.Colony formation assay was examined radiosensitivity of OSCC after salubrinal pretreatment;Cell apoptosis rate was detected by flow.By Western Blot assay,the activation of NF-κB–HIF-1α signaling pathway in oral cancer cell were analyzed at different time(0 min,20 min,1 h,3 h,6 h,12 h,24 h and 48 h)after 4 Gy X ray irradiation.After salubrinal pretreatment(20 μmol/L,12 h),we observed the activation of NF-κB–HIF-1α signaling pathway and the expression of apoptosis marker protein cleaved PARP in oral cancer cell.Results: 1.The results show that salubrinal increases the radiosensitivity of oral cancer cells.The radiosensitization ratios of KB and KBR cells were 1.19 and 1.24.2.IR+salubrinal group cell apoptosis rate increased compared with IR group,the difference is statistically significant(t = 0.72,5.86,P < 0.05).3.Western Blot assay revealed that the protein levels of phospho-p65,HIF-1α in KB cell increased from 1 h to 3 h and peaked at 6 h after radiation(t = 16,4.73,P < 0.05),while increased from 6 h to 12 h and peaked at 24 h after radiation in KBR cell(t = 8.33,5.97,P < 0.05).It revealed that the activation of NF-κB–HIF-1α was time-dependent in the radiation-induced oral cancer cells,while the inhibition of its after salubrinal.4.In addition,salubrinal increased radiation-induced cleaved PARP,a marker of apoptosis in oral cancer cells,whereas TNF-α,an activator of NF-κB,reversed the effect;Suggesting that inhibition of NF-κB increases ray-regulated apoptosis in oral cancer cells by salubrinal.5.Bay11-7082+IR group the expression of cleaved PARP increased compared with IR group,the difference is statistically significant(t = 1.85,2.11,P < 0.05).Pretreatment of NF-κB inhibitor Bay11-7082 to verify this conclusion.Conclusion: Inhibition of NF-κB increases radiation-induced apoptosis and regulates the radiosensitivity in oral cancer cells after ERS inhibition by salubrinal. |
