FAM83D Promotes The Malignant Process Of Lung Adenocarcinoma

Part ?:Expression profile of FAM83D in lung adenocarcinoma and its correlation with clinicopathological stagesObjectiveLung cancer,one of the most common malignancies,is the leading cause of cancer-related mortality worldwide.In recent years,the incidence of lung adenocarcinoma has elevated rapidly,and lung adenocarcinoma has become the major pathological type of non-small-cell lung cancer.Some studies had shown that the members of FAM83(Family with sequence similarity 83)proteins were closely related to the occurrence and development of several tumors.The aim of this study is to investigate the expression of FAM83D member and its correlation with the clinicopathological features and overall survival in lung adenocarcinoma.MethodsThe public database of the cancer genome atlas(TCGA)validated the up-regulated expression level of FAM83D in lung adenocarcinoma tissues compared to the adjacent normal tissues.Cox regression analysis was used to explore the relationship between FAM83D expression and overall survival in lung adenocarcinoma patients.60 cases of lung adenocarcinoma with complete clinical data were selected from Thoracic Surgery Department of Jiangsu Caner Hospital.Real-time fluorescence quantitative reverse transcription polymerase chain reaction(qRT-PCR)and immunohistochemistry(IHC)were used to evaluate the correlation between FAM83D expression and clinicopathological features in lung adenocarcinoma.ResultsThe expression of FAM83D in lung adenocarcinoma tissues was significantly higher than that in adjacent normal tissues.Chi-square test showed that in 60 cases of lung adenocarcinoma,the higher expression of FAM83D was associated with larger primary tumor size,lymph node metastasis and more advanced TNM stage.Kaplan-Meier survival analysis showed that lung adenocarcinoma patients with higher expression of FAM83D have worse overall survival than those with lower expression level of FAM83D.In consideration of FAM83D expression level,sex,T stage,N stage and TNM stage,multivariate Cox regression analysis showed that higher level of FAM83D and more advanced TNM stage were two independent risk factors for overall survival in lung adenocarcinoma patients.ConclusionOur data indicated that FAM83D is highly expressed in lung adenocarcinoma,and high level of FAM83D indicates poor overall survival in lung adenocarcinoma patients.FAM83D might be involved in the malignant progression of lung adenocarcinoma.Part II:Mechanism of FAM83D promoting malignant phenotype of lung adenocarcinomaObjectiveFAM83D might be a potential oncogene for promoting the malignant phenotype of lung adenocarcinoma.The aim of this study was to investigate the expression of FAM83D protein in lung adenocarcinoma and to analyze its relationship with the malignant phenotype of lung adenocarcinoma and its potential regulatory mechanism,and to provide a new target for the clinical treatment of lung adenocarcinoma.Methods1.The mRNA and protein expression of FAM83D in lung adenocarcinoma cell lines were detected by qRT-PCR and western blot.2.We designed specific siRNAs to silence the expression of FAM83D and observe the effect of FAM83D on cell proliferation,migration ability,cell cycle and apoptosis.3.We conducted nude mice xenograft experiment to investigate the effect of FAM83D on the growth of lung adenocarcinoma nodules.4.KEGG pathway analysis and GO enrichment analysis were used to predict the potential pathway where FAM83D might exert its oncogenic role.5.The mRNA and protein expression of cell cycle-related genes in FAM83D-knock down cells were detected by qRT-PCR and western blot.6.Rescue experiments were conducted to validate the potential targets of FAM83D in lung adenocarcinoma cells.Results1.The expression of FAM83D in lung adenocarcinoma cell lines was significantly higher than that in normal lung epithelial cells.The abilities of proliferation,migration and invasion of A549 and H1299 cells were significantly decreased after FAM83D was knocked down,and the cell cycle was arrested in G1 phase.2.The result of in vivo tumorigenesis experiments showed that the growth rate and volume of the tumor after silencing FAM83D were smaller than those in the control group.Immunohistochemistry staining of transplanted tumors showed that the expression of Ki-67 in the experimental group was significantly lower than that in the control group(p<0.05).3.qRT-PCR and western blot results showed that the expression of CCND1 and CCNE1 were both significantly inhibited after FAM83D was knocked down,when other cell cycle related proteins showed no significant change.4.After enforced over-expression of CCND1 or CCNE1 in FAM83D-knock down lung adenocarcinoma cells,the alleviated malignant phenotypes of cells could be partly rescued.ConclusionOur results show that FAM83D is highly expressed in lung adenocarcinoma and can promote the proliferation and migration of lung adenocarcinoma cells.FAM83D may exert its oncogene function by influencing the expression of CCND1 and CCNE1 to promote the process of cell cycle.So FAM83D might serve as a potential therapeutic target to provide new ideas for the diagnosis and treatment of lung adenocarcinoma.