Abstract: 【Abstract】Objective To explore effect of manganese superoxide dismutase (MnSOD) overexpression on rediosensitivity in the esophageal cancer cell line in action of buthionine sulfoximine (BSO). Methods Overexpression of MnSOD cDNA by lentivirus to get stable transfected TE-1 cell lines of MnSOD overexpression (TE-1Mm). Reverse transcription polymerase chine reaction (RT-PCR）and Western blot were then introduced to detect the target gene with respect to its expression in esophageal TE-1 cells. Plating efficiency was also conducted as to the influence of MnSOD overexpression that might be found on TE-1 cells proliferation. Colorimetric 3-[4,5-dimethy thiazol-2-yl]-2, 5-diphenyltetrazolium bromide(MTT) assay, flow cytometry and western blot were also conducted as to the influence of the MnSOD overexpression that might be found on proliferation of TE-1 cells treated with BSO and radiation. Results: RT-PCR and Western blot showed that TE-1 cells transfected with MnSOD contained the target genes in overexpression. Plating efficiency was reduced in the MnSOD overexpression transfected cell line and decreased the plating efficiency to 23.0±2.7%. While, the TE-1 cell had a higher plating efficiency (34.7±4.2%). Furthermore, apparent apoptosis of TE-1Mm cell induced by transfected moderate MnSOD cDNA (10.6±1.0%) was indicated by Annexin V-FITC/PI staining compared to TE-1 cell (2.6±0.2%). Moreover, in multitarget single-hit model-fitting survival curves, the values of D0, Dq, N, and SER in TE-1Mm cell lines were less than in TE-1 cell. FCM results indicated that TE-1Mm of reactive oxygen species (ROS) fluorescence index were 0.81±0.04 compared to TE-1 cell (1.00±0.06). Western blot demonstrated that TE-1Mm had a higher MnSOD protein expression than those of TE-1 treated with BSO and radiation. Conclusion MnSOD overexpression could increase the radiosensitivity of esophageal cancer cell by inhibiting cell proliferation, inducing cell apoptosis and decreasing ROS concention in combination with BSO.

Key words: Manganese superoxide dismutase, Buthionine sulfoximine, esophageal carcinoma, radiosensitivity