Objective      To determine the effect of fibronectin extra type Ⅲ domain A (EDA-FN)  on the proliferation and apoptosis of human colorectal cell line SW480.     Methods     The expression of EDA-FN in SW480 cells was silenced by lentiviral infection. Expression of EDA-FN was examined by Western blot analysis. MTT assay was used to analyze cell viability after infection. Cell apoptosis was analyzed by flow cytometry. The expression of Bax and Bcl-2 were examined by Western blot analysis.     Results      As compared with the blank control cells (without lentiviral infection) and negative control cells (empty vector infection)

the infection of lentiviral inhibited the expression of EDA-FN in SW480 cells. The proliferative capacity of cells was decreased in 24

48

72 and 96 h after lentiviral infection

and all were significantly lower than blank control group and negative control group (P0.05). The apoptotic rate of SW480 cells after lentiviral infection  was (47.76±1.51)%

significantly higher than those of blank control group and negative control group [(3.09±1.13)% and (3.71±0.42)% respectively

P0.05]. Western blot analysis showed that the expression of Bax was increased

while that of Bcl-2 was decreased.     Conclusion      EDA-FN induces the proliferation and inhibits the apoptosis of human colorectal cacer SW480 cells. The inhibitor of EDA-FN may be a new target in the treatment of the malignant tumors.