Studies On The Function And Mechanism Of Sprouty1 In Lung Adenocarcinoma

Lung cancer which is a fatal malignant disease with poor prognosis and its incidence increasesd year by year both in worldwild and in China,is becoming a serious threat to human public health problems.Although there are a large number of molecular biology experiments for lung cancer,but the mechanism of the formation and development of lung cancer is still not very clear yet.According to previous research,sprouty1 is known as an inhibitor of RTK signal pathway,which can affect various kinds of cell proliferation,differentiation and migration by regulating EGF,FGF or PDGF induced signal pathway.In view of the fact that there is no report about the expression and regulation mechanism of sprouty1 in lung adenocarcinoma.Firstly,we construct the sprouty1 knockout transgenic mouse model,and use immunohistochemical staining and immunofluorescence staining to verify the function of sprouty1 in lung tissue,and to observe the phenotype of lung tissue in sprouty1 knockout mice.Secondly,HE staining and immunohistochemical staining were utilized to compare the incidence of lung cancer and expression of TTF1 between the transgenic mice and wildtype mice.We used cell transfection technique in vitro to construct sprouty1 overexpression A549 cell line,and try to investigate the effect of sprouty1 on the proliferation and differentiation of lung cancer cells.Finally,immunofluorescence staining and western-blot experiments were performed to explore the biological function and the mechanism of sprouty1 in lung adenocarcinoma.Based on our experimental results,we draw the following conclusions:1)sprouty1 is highly expressed in type II alveolar epithelial cells(AEC II),the expression of PCNA and Ki67 in AEC II were induced after sprouty1 gene knockout.The role of sprouty1 was to inhibit AEC II proliferation.2)the incidence of lung cancer in sprouty1 knockout mice was significantly higher than in wild type mice(P <0.01),and the pathologic type of tumor was in line with lung adenocarcinoma.3)the expression of cell cycle-related pretein in sprouty1 overpression A549 cells decreased indicating that sprouty1 can inhibit the proliferarion of lung adenocarcinoma cells.4)sprouty1 gene knockout led to increased expression of EGFR,FGFR2 and p ERK,and we also can observe the p ERK and PCNA co-staining,indicating that sprouty1 can regulate cancer cell proliferation via EGF and FGF-introduced ERK signal transduction pathway.The expression of vimentin,?1-integrin,SMA,PDGFR? and fibronectin decreased in sprouty1 knockout mice,which showed that sprouty1 could inhibit the invasion of lung adenocarcinoma by regulating the EMT of cells.Based on our experimental results,we believe that sprouty1 can be considered as a tumor suppressor gene of lung adenocarcinoma,which can suppress initiation and development of lung adenocarcinoma via inhibiting EGF or FGF-mediated Ras / ERK signal pathway and inhibiting of adenocarcinoma cells EMT.All these implicate sprouty1 may be a new target for lung cancer therapy.