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Objective:To study the gene expression of nuclear factor erythroid-2-related factor 2 (Nrf2), glutathione-S-transferase (GST) and interleukin-1 β (IL-1β) in A549 cells exposed to hyperoxia and cell apoptosis after siRNA interference with Nrf2.Method:Normal A549 cell lines were assigned into normoxia+siRNA group, normoxia+control group, hyperoxia+siRNA group and hyperoxia+control group according to whether siRNA interference was used and the exposure environment (normoxia/hyperoxia). The hyperoxia environment contained 95%O 2 and 5%CO 2. The levels of mRNA expression of Nrf2, GST and IL-1β were detected using quantitative real-time polymerase chain reaction (qRT-PCR). Flow cytometry was used to examine cell apoptosis of the hyperoxia+control group and hyperoxia+siRNA group at different time points. Analysis of variance (ANOVA) was used to test the relative gene expression and apoptosis of A549 cells. Result:(1) Compared with the normoxia+control group, the expression of Nrf2 and GST in the hyperoxia+control group was significantly increased ( P<0.05), and the expression of IL-1β was significantly decreased ( P<0.05); the expression of Nrf2 and GST in the normoxia+siRNA group decreased significantly ( P<0.05), while the expression of IL-1β increased significantly ( P<0.05). (2) Compared with the normoxia+siRNA group, Nrf2 expression in the hyperoxia+siRNA group showed no significant changes ( P=0.230), GST expression increased slightly ( P=0.057), and IL-1β expression decreased slightly ( P=0.112). (3) Compared with the hyperoxia+control group, the expression of Nrf2 and GST in the hyperoxia+siRNA group decreased significantly ( P<0.05), and the expression of IL-1β increased significantly ( P=0.042). (4) Compared with the hyperoxia+control group, the apoptosis of A549 cells in the hyperoxia+siRNA group increased significantly at 24 h, 48 h and 72 h ( P<0.05). Conclusion:After interfering with Nrf2, siRNA may regulate the expression of GST and IL-1β, preventing oxidative stress, reducing inflammatory response and inhibiting apoptosis.
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Background and purpose:The pro-oncogene Bmi-1 is a member of the polycomb-group family, can regulation of the proliferation and self-renewal of normal and tumor stem cells. In recent years, Bmi-1 has been found that it is overexpressed in varieties of human malignant tumors. The study aimed to observe the effects of Bmi-1-siRNA on the growth capacity of lung cancer cell line A549 in vivo and in vivo, and explore its mechanism. Methods:The most effective one as a target sequence was chosen from four Bmi-1 siRNA sequences which were designed by our lab, and one random sequence was chosen as a negative control. In short, the chemically synthesized siRNA and control sequences were connected to a retrovirus expressing vector, pSUPERretro-Neo plasmid, and then transfected into A549 cells. The stably transfected cells were cultured and passed. The level of mRNA and protein of Bmi-1 in A549 cells were assessed by RT-PCR and Western blot respectively. The proliferations of A549 cells in vivo was analyzed with MTT, trypan blue exclusion and plate colony forming methods. Flow cytometry was used for cell cycle analysis. The potency of tumorigenesis was observed in nude mouse through hypodermic inoculation of A549 cells. The expressions of cyclin D, p21/27, p-AKT and PTEN were analyzed by Western blot. Results:Compared to A549-ctr and A549-wt cells, Bmi-1 mRNA and protein levels all signiifcantly reduced in A549-Bmi-1-siRNA cells. Bmi-1-siRNA inhibited the growth, colony formation in vitro and tumorigenesis in vitro of A549 cells, and the interference cells cell cycle arrested in G1 phase. In A549-Bmi-1-siRNA cells, p-AKT and cyclinD1 expression were down-regulated while p21/p27 and PTEN were up-regulated. Conclusion:Silencing Bmi-1 gene inhibits the proliferation of A549 cells through G1 phase arrest, which involves the downregulation of cyclin D/p-AKT and upregulation of p21/p27/PTEN.
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Objective To investigate the effects of siRNAs targeted protein kinase C ?(PKC?) on the proliferation and apoptosis of A549 cell line.Methods Six PKC? siRNAs were designed and chemical synthesized. Candidate PKC? siRNA was transfected into A549 cells,PKC? mRNA level was determined by semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR). Then,the effects of more effective PKC? siRNAs on A549 were further investigated by using clone formation assay,Hoechst 33258 staining,propidium iodide (PI) staining,Annexin V-FITC and PI dual staining and western blot. Results Six candidate PKC? siRNAs were designed and named as No.1,No.2,No.3,No.4,No.5 and No.6 PKC? siRNA. Compared with controls,PKC? mRNA levels were all significantly downregulated and the cell proliferation was inhibited in A549 cells treated with candidate PKC? siRNAs except No.5 (P