The Mechanism Of FAM83A Promoting The Proliferation And Invasion Of Lung Adenocarcinoma

Lung cancer is one of the malignancies with the highest morbidity and mortality in the world,and its main types are small cell lung cancer and non-small cell lung cancer(NSCLC).The two most common types of non-small cell lung cancer are lung adenocarcinoma(LUAD)and lung squamous cell carcinoma(LUSC).Meanwhile,the prognosis of lung cancer is closely related to the stage of tumor development.After treatment,the five-year survival rate of early NSCLC is over 40%,but the five-year survival rate of advanced NSCLC is less than 10%.In recent years,advances in the identification of tumor driver genes have led to the development of many new targeted therapies that can provide more sophisticated treatment for lung adenocarcinoma patients.However,when treated with targeted drugs,tumor cells develop resistance to targeted drugs by modulating signaling pathways.At the same time,targeted drugs can also produce toxicity to normal cells in the body,inhibiting growth of normal cells.Therefore,it is necessary to further find therapeutic targets for LUAD and utilize potential therapeutic targets to the prevention and treatment of NSCLC.Many studies have shown that family member A with a sequence similarity of 83(FAM83A)is a clear tumor-specific gene.However,studies on the mechanism of FAM83A in tumors are still limited.Objective: To reveal the expression levels of FAM83A in lung cancer,and to analyze the relationship between FAM83A and the clinicopathological factors and prognosis of lung cancer.Exploring the role and mechanism of FAM83A in the process of proliferation and invasion in lung cancer cells.Methods: UALCAN online database was used to analyze the expression of FAM83A in lung adenocarcinoma and lung squamous cell carcinoma,as well as the relationship between FAM83A expression level and poor prognosis.The relationship between FAM83A and the clinicopathological factors and prognosis of lung cancer was analyzed by cBioPortal database.The expression of FAM83A in H1299 and A549 lung cancer cells was up-regulated or down-regulated by transfection of FAM83A gene and SiRNA interference.Western Blot was used to detect the effect of FAM83A on key proteins of the Wnt signaling pathway,the Hippo signaling pathway and epithelial mesenchymal transformation(EMT).The effects of FAM83A expression level on the proliferation and invasion ability of non-small cell lung cancer were detected by matrigel invasion assay,cell proliferation assay and colony formation assay.By giving Wnt signaling pathway and GSK3β inhibitors to counteract the effect of FAM83A expression level changes on the Hippo signaling pathway,the expression level of YAP,the downstream effector of Hippo signaling pathway was detected,to further explore the possible mechanism of FAM83A promoting the development of lung cancer.Results:1.The expression level of FAM83A mRNA in lung squamous cell carcinoma and lung adenocarcinoma was significantly higher than that in normal lung tissue,and the high expression of FAM83A was correlated with poor prognosis of patients with lung cancer.Meanwhile,the mRNA level of FAM83A was positively correlated with the tumor(T)stage,lymph node(N)stage,metastasis(M)stage,and total TNM stage.2.The expression level of FAM83A was up-regulated by FAM83A gene transfection in H1299(H1299-FAM83A)and A549(A549-FAM83A)cells.Compared with those of control cells,the proliferation rate and number of colony formations of lung cancer cells were significantly increased.In contrast,when the expression of FAM83A was downregulated with SiRNA interference in H1299(H1299-SiFAM83A)and A549(A549-SiFAM83A)cells,the proliferation rate and number of colony formations of lung cancer cells were significantly decreased compared with those of control cells.The Matrigel? invasion assay showed that overexpression of FAM83A enhanced the invasive ability of H1299-FAM83A and A549-FAM83A.3.After FAM83A gene transfection of H1299 and A549 cells,the expression levels of active-β-catenin was significantly increased,the expression of MMP7,c-myc,cyclin D1,the target proteins of the Wnt pathway,were also up-regulated.The expressions of Twist,Snail and vimentin,the EMT-inducing transcription factors,were all up-regulated,while that of E-cadherin was down-regulated.After SiFAM83A interference,the opposite result can be obtained.4.After transfection of FAM83A with H1299 and A549 cells,the expression of LATS1 and MST1,the upstream proteins of the Hippo signaling pathway,were inhibited,while the expression level of YAP was significantly increased.After SiFAM83A interference,we got the opposite result.5.After transfection with FAM83A in H1299 cells,the proliferation and invasion ability of tumor cells was significantly enhanced.Then we added the Wnt signaling pathway inhibitor XAV-939 to H1299-FAM83A cells.Compared with H1299-FAM83A cells treated with DMSO,the proliferation rate and number of colony formations of H1299-FAM83A cells treated with XAV-939 were significantly decreased.Similarly,the Matrigel? invasion assay showed that H1299-FAM83A cells treated with XAV-939 had a reduced invasion capacity compared to the H1299-FAM83A with DMSO group.6.The expression level of YAP was up-regulated in H1299-FAM83A cells,however,when we added XAV-939,an inhibitor of Wnt/ β-catenin signaling pathway,in H1299-FAM83A cells,the expression of YAP was down-regulated.The expressions of cyclin E and CTGF,the downstream targets of YAP,were also up-regulated in H1299-FAM83A cells but were down-regulated after the addition of XAV-939.We then used CHIR-99021,a GSK-3α/β inhibitor,in H1299-SiFAM83A cells for further investigation.The expression of YAP and its downstream targets cyclin E and CTGF were decreased in H1299-SiFAM83A cells but were restored after inhibiting the activity of GSK-3β using CHIR-99021.Conclusion:1.Expression of FAM83A is increased in lung cancers and correlated with TNM stages and poor survival.2.FAM83A enhances the proliferative and invasive abilities of lung cancer cells by the Wnt signaling pathway.3.FAM83A enhances the activity of the Wnt signaling pathway and the EMT process of lung cancer cells.Meanwhile,FAM83A inhibits the activation of the Hippo signaling pathway.4.GSK3β and the Wnt signaling pathway contribute to FAM83A induced YAP activation.