The Effect Of Macrophage Derived Tranforming Growth Factor-β Epithelial Mesenchymal Transition In Non Small Cell Lung Cancer

Background and Objective:Lung cancer presents the highest morbidity and mortality in malignant tumors,which is one of the biggest threats to human health and life.Lung cancers are classified into four types:squamous carcinoma,adenocarcinoma,large cell carcinoma and small cell carcinoma.The former three types are known collectively as non small cell lung cancer(NSCLC),which constitutes 80-85%of all lung cancers and have similar reactions to chemotherapy drugs.Because of surgical resection can’t cure tumors,chemotherapy for NSCLC treating plays an irreplaceable role,and is more and more widely used.In recent years,molecular targeted drugs have become a main method for cancer treatment,because of its strong specificity,small side effects,good treatment effect.Epidermal growth factor receptor-tyrosine kinase inhibitor(EGFR-TKI)is a typical therapy drug for the treatment of NSCLC.As EGFR-TKI drugs are becoming more and more widely used clinically,EGFR-TKI resistance has aroused increasing attention,and how to inhibit EGFR-TKI acquired drug resistance of NSCLC patients and reverse drug resistance have become an ugent problem to besolved in EGFR-TKI treatment for NSCLC.EGFR-TKI acquired drug resistance have complicated molecular mechanisms,and among these epithelial to mesenchymal transition(EMT)is one of the most important aspects.EMT is a fundamental biological process,wherein converting from epithelial cells epithelial phenotype to mesenchymal phenotype,and with the characteristics of cell migration and invasion ability enhancement.The cell-cellcontact between epithelial cells mainly rely on specific intercellular linking structures between adjacent cells,such as adjacent junction、gap junction and desmosomes,etc,and one of the main structural characteristics of EMT is their loose adjacent junction.E-cadherin is a kind of cell membrane adhesion protein,which is expressed in almost all epithelial cells,and its role is to maintain the connection between epithelial cells.The lack of E-cadherin expression can lead to weakened cell adhesion strength and loose the connection,which makes it easily for epithelial cells to migrate to surrounding stroma from primary focal.Vimentin is an intermediate micro-silk protein,and it is only secreted in mesenchymal tissue,but not expressed in epithelial tissue.Once the Vimentin is expressed in,it means the cancer cells had turned from epithelial phenotype to mesenchymal phenotype.So weakened E-cadherin express and enhanced Vimentin express means the occurence of EMT.The occurence and development of tumor is a gradual evolutive process with multiple factors participating in,and is affected by the changes of cell itself and the differences of environment outside.The process often has three stages,namely necrosis removing,equilibrium phase and immune escaping,and change the tumor environment into a promoting one for the occurence and development of tumor,which is called the tumor microenvironment.Macrophages are important components of the tumor microenvironment,which can accelerate the occurrence,progression and metastasis of tumor.Macrophages may play its specific biological effects when NSCLC tumor cells attacked by TKI drugs,and make the tumor cells become drug resistant.However,the process is not clear and worth exploring.In the process of EMT,tumor is influenced by a variety of cytokines and transcription factors from tumor microenvironment,among which the most important factor is transforming growth factor-β(TGF-β),TGF-β is mainly secreted by macrophages.In the process of tumor occurrence and development,TGF-β has a positive effect on tumor cells EMT.In this study,we detect the expression of Vimentin as the marker of EMT in NSCLC tissues,whose positive expression indicate EMT occurrence,detect the expression of CD68 as the marker of NSCLC tumor interstitial macrophages,to confirm the expression of macrophages.Meanwhile,we detect the expression of TGF-β secreted by macrophages,and discuss the effects of macrophage and its secreted TGF-β on EMT in NSCLC by analyzing the relationship between TGF-β expression and the clinicopathological parameters of NSCLC patients.Hopefully,the research could provide some useful clues for the study of NSCLC TKI resistance mechanisms.Methods:The samples of NSCLC and their surrounding tissues were collected from the Affiliated Hospitals of Dalian Medical University.Immunohistochemistry method was used to detect the expressions of E-cadherin,vimentin,CD68 and TGF-βprotein in 96 samples of NSCLC.Five clear background under a microscope high power field of vision were randomly selected,and half quantitative analysis was accomplished according to the positive cell percentage of tumor cells or mesenchymal cells and tinting strength.The SPSS 17.0 statistic software was used to analyze the correlations between the protein expressions clinicopathological agents(gender,age,smoking history,histological type,differentiation,metastasis or not),as well as the relationship among these protein expressions.Results:1.EMT occured 35 cases(36.46%)in 96 cases of NSCLC.2.In Vimentin positive and negative groups,the proportion of adenocarcinoma patients were 27/35(77.14%)and 33/61(54.10%)respectively,the proportion of squamous carcinoma patients were 6/35(17.14%)and 22/61(36.07%)respectively,Vimentin protein expression in adenocarcinoma group was significantly higher than in squamous cell carcinomas group(P<0.05),but there was no significant correlation between with the patient’s gender,age,smoking status,transfer or not,degree of differentiation(P>0.05).3.In EMT positive and negative groups,the positive expression of CD68 proportion were 24/35(68.57%)and 31/61(50.82%)respectively,(P>0.05).In EMT positive group high differentiated adenocarcinoma CD68 protein expression in patients showed a ratio of 13/15(86.67%),significantly higher than 14/25 of the EMT negative group(56.00%),P<0.05,but had no significant correlation with the patient’s gender,age,smoking status,transfer or not,degree of differentiation(P>0.05).4.In EMT positive and negative groups,TGF-β positive proportion were 12/35(34.29%)and 24/61(39.34%)respectively,P>0.05.The expression of TGF-β had no significant correlation with patient’s gender,age,smoking status,pathological type,transfer or not,degree of differentiation(P>0.05).Conclusion:1.It is more likely to occur EMT in lung adenocarcinoma patients.2.The occurence of EMT in high differentiation in patients with lung adenocarcinoma might have a close relationship with macrophages.