The effect of STC1 gene on radiosensitivity of human lung cancer A549 cell line

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 (STC1-siRNA) and the non-interfering siRNA (negative control group) were transfected into the human lung cancer A549 cells by Lipofectamine™2000, 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. Key words: STC1 gene; Non-small cell lung cancer; Radiosensitivity; STAT3 signaling pathway