Basic Fibroblast Growth Factor Regulate Epithelial To Mesenchymal Transition On A549Cells

Objective:Development of metastasis is one of main causes of lung cancer-related death.Tumor metastasis is a complicated process which is regulated by all kinds offactors and genes. The main mechanisms are decrease of the adhesion capacitybetween tumor cells, degradation of extra-cellular matrix and mobility of tumorcells induced by growth factors and chemokine. The basis of tumor metastasis isthe decrease of adhesion capacity and the increase of cell mobility. Epithelial tomesenchymal transition is the foundation of tumor metastasis. Epithelial tomesenchymal transition is a process that generates epithelial cells to lose cellpolarity and acquire a mesenchymal morphology. More and more studies havereported that epithelial to mesenchymal transition（EMT）play an important rolein metastasis of epithelial-oriented tumors. Basic fibroblast growth factor（bFGF）which has many biological functions is one of main inducers of occurrence ofEMT. This study is aim to investigate the effect of epithelial to mesenchymaltransition (EMT) in A549lung cancer cells on the invasion and metastasis bybFGF.Methods: A549cells were treated by different concentration of bFGF for differentduration. The morphological changes were observed by inverted phase contrastmicroscopy. The expression of the epithelial marker E-cadherin andmesenchymal marker vimentin was evaluated by western-blot analysis andindirect immunofluorescence staining. The effect of bFGF on migration andinvasion of A549was detected by scarification assay and transwell assay.Results:First, after treated by bFGF, A549cells showed a loss of the adherentphenotype and subjected to morphological changes turned from pebble shape intofusiform shape, a myofibroblast-like morphology, under phase-contrastmicroscopy. Second, The expression of epithelial marker E-cadherin weredecreased, and the expression of mesenchymal marker vimentin increased afterbFGF treatment shown by Western blot assay. And this alteration was dependenton the concentration of bFGF and action time. Third, Scarification test showedthat the migration potential of A549cells was significantly increased after bFGFtreatment. Fourth, The invasive capacity of A549increased after bFGF treatment.Conclusion:These results suggested that:1) Basic fibroblast growth factor mediatedmorphological and molecular change of EMT in A549lung adenocarcinoma cellline.2) EMT is one of the important mechanisms for invasion and metastasis oflung cancer.