Radioprotective effect of fusion antioxidant enzyme GS1XR on nasopharyngeal epithelial cells
Objective:To investigate the radioprotective effects of the fusion antioxidant enzyme GST-SOD1-X-R9 (GS1XR) on normal nasopharyngeal epithelial cells (NP69) and its potential mechanisms. Methods:NP69 cells were cultured and divided into the following groups:untreated control (Untr) group,EGFP-GS1 group,EGFP-GS1R group,and EGFP-GS1XR group. The transmembrane effect of different fusion antioxidant enzymes was evaluated at a concentration of 0.5 mg/mL. The cytotoxicity of the three enzymes within a concentration range of 0 to 1 mg/mL was determined using the CCK-8 assay. ROS levels in NP69 cells were measured using a DCFH-DA fluorescent probe following exposure to 0～6 Gy X-ray and varying doses (0～1 mg/mL) of GS1XR. In further experiments,NP69 cells were divided into blank control (Untr) group,4 Gy X-ray only group (Ctrl),and groups pre-treated with GS1,GS1R,GS1XR,or Amifostine (AMFT,4 μg/mL) before X-ray exposure. ROS levels,apoptosis rate,Nrf2 nuclear translocation,and expression of antioxidant gene GCLC,anti-apoptotic factor Bcl-2,and pro-apoptotic factor BAX were evaluated using flow cytometry and WB analysis. Results:EGFP-GS1 lacked transmembrane ability,whereas EGFP-GS1R and EGFP-GS1XR efficiently crossed the NP69 cell membrane (P<0.0001). After 24 hours of treatment,all three fusion antioxidant enzymes maintained cell viability above 80％,with the GS1XR-treated group maintaining cell viability above 100％. Exposure to 4 Gy X-ray significantly increased intracellular ROS levels (P<0.01),while GS1XR effectively reduced radiation-induced ROS in a dose-dependent manner. Compared to the Ctrl group,GS1XR significantly decreased intracellular ROS levels (P<0.05),promoted Nrf2 nuclear translocation (P<0.01),upregulated the expression of antioxidant gene GCLC (P<0.0001),and reduced the apoptosis rate (P<0.0001). Additionally,it increased the expression of anti-apoptotic factor Bcl-2 (P<0.001) and downregulated pro-apoptotic factor BAX (P<0.05). The overall protective effects of GS1XR were similar to those of GS1R and comparable to the effects of Amifostine. Conclusion:The fusion antioxidant enzyme GS1XR exhibits significant radioprotective effects on NP69 cells,likely through its ability to enter cells,eliminate radiation-induced ROS,activate the Nrf2 signaling pathway,and regulate the expression of Bcl-2 and BAX. GS1XR shows potential as a novel radioprotective agent.
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维普
