The Effect Of Nur77 On Radiosensitivity Of Lung Adenocarcinoma Cells And Its Mechanism

Objective:To investigate the influence of Nur77 on the radiosensitivity of lung adenocarcinoma cells.Methods:Transfect the lung adenocarcinoma A549 cell line with small interfering RNA,respectively transfect the silenced small interfering RNA si-Nur77 and the control small interfering RNA si-NC to down-regulate the expression level of Nur77 in the cells.Western Blot experiment is used to detect transfection efficiency;Clone formation experiment detects the effect of down-regulation of Nur77 expression on radiosensitivity of lung adenocarcinoma A549 cells;Flow cytometry was used to show the effect of down-regulation of Nur77 expression on cell cycle and apoptosis of lung adenocarcinoma A549 cells;The Cancer Genome Atlas(TCGA)database was used to analyze the expression of Nur77 in human lung adenocarcinoma and its relationship with survival.Results:1.Western Blot was used to detect the silencing efficiency of si-Nur77 in A549 cells,the expression level of Nur77 in A549 cell line of the si-Nur77 group was significantly lower than that of the si-NC group.2.Clone formation experiments came out that Do and SF2 of A549 cells transfected with si-Nur77 were higher than those of A549 cells transfected with si-NC,and the SER value was 0.70.It is suggested that down-regulation of Nur77 leads to a decrease in radiosensitivity of lung adenocarcinoma A549 cell line.3.Flow cytometry experiments to detect the cell cycle of A549 with the result that,the proportion of cells in the G2/M phase of the lung adenocarcinoma A549 cell line transfected with si-Nur77 was significantly reduced,compared with the control cells transfected with si-NC,the difference is statistically significant(P<0.05).4.Flow cytometry detection of A549 cell apoptosis showed that ompared with the control cells transfected with si-NC,the proportion of apoptotic cells in the lung adenocarcinoma A549 cell line transfected with si-Nur77 decreased,the difference is statistically significant(P <0.05).5.The result of statistical analysis of TCGA database,showed that compared with normal adjacent lung tissue samples,the expression of Nur77 in lung adenocarcinoma was significantly lower,and the difference was statistically significant(P<0.05).6.The survival analysis results of the TCGA database show that when Nur77 is highly expressed,lung adenocarcinoma shows a higher survival rate,and the difference is statistically significant(P<0.05).Conclusion:(1)Down-regulation of Nur77 expression can lead to increased radioresistance of lung adenocarcinoma A549 cell line.(2)Down-regulating the expression of Nur77 can lead to a decrease in the ratio of cells in G2/M phase and cell apoptosis of lung adenocarcinoma A549 cell line,it may be one of the mechanisms that induce radioresistance of lung adenocarcinoma A549 cell line..4.TCGA database analysis shows that the expression level of Nur77 gene in lung adenocarcinoma tissue is lower than that in normal lung tissue.Patients with lung adenocarcinoma with high Nur77 gene expression have a higher survival rate.