Molecular Regulatory Mechanism Of DEK In Human Lung Adenocarcinoma Cells A549

PURPOSE:Oncogene DEK exists extensively as a highly conserved phosphorylated protein in cell nucleus,with high expression in a variety of human malignant tumors,showing high correlation with occurrence and development of tumors.DEK plays a role in mRNA slicing and signaling pathway by changing chromatin structure and repairing DNA,or regulates cell proliferation,differentiation,apoptosis,metastasis and aging by serving as a transcription factor or other ways,thus,it plays a major part in formation of tumor cells.In recent years,several studies of the promotion of tumor development by DEK have been conducted,however,mature findings on correlation between DEK and lung cancer and mechanism of DEK in lung cancer has not yet been established.Previous study shows higher expression quantity of DEK protein in human lung cancer tissue than in normal tissues,indicating possible important role of DEK in lung cancer pathogenesis.Therefore,the research,based on previous work,further studies the effect of DEK silencing on lung cancer transcriptome on cell level,and the mechanism of DEK in lung cancer,providing a new route for lung cancer treatment and experimental evidence.METHODS:The experiment examined DEK expression level variance in six different kinds of lung cancer cell lines,through real-time fluorescent quantitative RT-PCR and Western Blotting,The A549 cell line with endogenous high expression level of DEK was screened out,and DEK silencing through lentivirus vector RNAi.The experiment examined differently expressed genes induced by DEK silencing through RNA-Seq,then appraised correlation between differently expressed genes and lung cancer through GO analysis and Pathway analysis,at last,verified analytical accuracy on cellular level:influence of DEK silencing on cell proliferation capability through MTT method,on cell cycle through PI staining method,on cell apoptosis through Annexin V-FITC/PI cell apoptosis detection agent kit.Besides,the expression level of IGFBP3/IGF-1R/AKT pathway related genes was also examined through real-time fluorescent quantitative RT-PCR and Western Blotting.RESULTS:Results of GO analysis and Pathway analysis appraising correlation between differently expressed gene induced by DEK silencing and lung cancer in A549 cell line show that DEK is closely associated with cell growth and death.Further,we transfected A549 cells with siRNA to reduce DEK expression level and detect the effect of DEK silencing on the function of A549 cells.The results showed that DEK silencing could inhibit the proliferation of A549 cells,lead to G1 phase retardation in cell cycle and promote cell apoptosis.At last,we examined correlation between gene expression level on IGFBP3/IGF-1R/AKT pathway and DEK,and the results showed that the expression level of IGFBP3 gene was negatively correlated with the expression level of DEK,and the expression of IGF-1R,p-AKT and AKT was positively correlated with the expression level of DEK.Conclusion:based on above results,we conclude that,DEK silencing may lead to G1 phase retardation in cell cycle of A549 lung adenocarcinoma cell,inhibit proliferation and promote apoptosis.Its molecular mechanism is correlated with IGFBP3/IGF-1R/AKT pathway.