Objective:To investigate the effects of interleukin 27(IL-27) gene transfection on proliferation of human lung cancer A549 cells and expression of signal transducer and activator of transcription 3(STAT3).Methods:A549 cells were cultured and divided into A549 cell group(non-transfected cells), A549-HisB cell group(A549 cells transfected with pcDNA3.1-HisB empty plasmid), A549-IL27 cell group(A549 cells transfected with pcDNA3.1-HisB-IL-27 plasmid). RT-PCR and ELISA were used to detect the transfection results of IL-27, CCK-8 assay was used to detect the effect of IL-27 gene transfection on the proliferation of A549 cells,and the effects of transfection of IL-27 gene on cell cycle and apoptosis of A549 cells were determined by flow cytometry. Western blot and qRT-PCR were used to detect the expressions of STAT3 protein and mRNA in A549 cells.Results:A549-IL27 cells were amplified into IL-27p28 gene and IL-27EB13 gene band,while A549 cells and A549-HisB cells were not amplified. After 4 hours' culture of transfected cell, the expression of IL-27 could be detected in A549-IL27 cell culture medium, but it couldn't be detected in A549 cell and A549-HisB cell culture medium. After 24, 36, 48 and 60 hours' culture of transfected cells, the proliferation of A549-IL27 cells decreased significantly, which was lower than that of A549 cells and A549-HisB cells(P<0.05). Compared with A549 cells and A549-HisB cells, the proportion of G0/G1 phase in A549-IL27 cells increased significantly, the proportion of G2/M phase decreased significantly, and the apoptotic rate increased significantly(P<0.05). The expression levels of STAT3 protein and mRNA in A549-IL27 cells decreased significantly, which were lower than those in A549 cells and A549-HisB cells(P<0.05). The expression of B-cell lymphoma-2(Bcl-2) protein in A549-IL27 cells decreased and the expressions of B cell lymphoma/leukmia-2 associated X protein(Bax) and cysteinyl aspartate specific proteinase 3(Caspase-3) proteins increased, which were significantly different from those in A549 cells and A549-HisB cells(P<0.05). Conclusion:Transfection of IL-27 gene can inhibit the proliferation and promote apoptosis of human lung cancer A549 cells, which may be related to inhibiting STAT3 expression and blocking its signal transduction.
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