ABSTRACT
Objective To investigate effect of stanniocalcin-1 (STC1) gene on the proliferation,apoptosis and radiotherapy sensitivity of non-small cell lung cancer.Methods The STC1 siRNA (STC 1-siRNA) and the non-interfering siRNA (negative control group) were transfected into the human lung cancer A549 cells by LipofectamineTM2000,and the blank control group was established.The expression level of STC1 protein was detected after transfection for 48 h by Western blotting.Clone forming test was adopted to detect the proliferation of A549 cells after STC1-siRNA and irradiation treatment.CCK8 assay was performed to detect the cell viability after treatment with STC1-siRNA and STC1-siRNA+8 Gy.The cell apoptosis was detected by flow cytometry.The expression levels of Ki67,Bax,STAT3 and p-STAT3 proteins were quantitatively measured by Western blotting.Results The expression level of STC1 protein in the A549 cells transfected with STC1-siRNA was significantly down-regulated than that in the blank control group (P＜ 0.05).Compared with the blank control group,the sensitization ratio was significantly enhanced after STC1-siRNA transfection.Compared with the blank control group,the cell viability and the expression levels of Ki67 and p-STAT3 protein were significantly decreased,whereas the apoptosis rate and the expression of Bax protein were significantly increased in the STC1-siRNA group.Compared with the STC1-siRNA group,the cell viability and the expression levels of Ki67 and p-STAT3 proteins were significantly decreased,whereas the cell apoptosis rate and the expression of Bax protein were remarkably increased in the STC1-siRNA+ 8 Gy group (all P＜0.05).Conclusion Inhibition of STC1 gene expression can enhance the radiotherapy sensitivity and down-regulate the STAT3 signaling pathway in non-small cell lung cancer.