Objective   To investigate the effect of transforming growth factor-β1 (TGF-β1) on cell cycle

cell proliferation

and invasive capacity of human colon cancer cells of the line SW480

for its role in colon carcinogenesis and development

as well as its application in gene therapy for colon cancer with RNA interference.    Methods   The recombinant expressing plasmids pEGFP-N1-TGF-β1 was constructed and transfected into SW480 cells by Lipofectamine 2000. The expression of TGF-β1 mRNA and protein in the transfected SW4

80 cells were detected by fluorescent microscopy

RT-PCR and Western blot analysis respectively. The cell proliferation of SW480 cells was tested by MTT assay

the cell cycle was analyzed by flow cytometry

and the invasion ability of SW480 cells were investigated by Transwell-matrigel invasion chambers.    Results   After transfected into SW480 cells

both the mRNA and protein levels of TGF-β1 were effectively increased (P0.05). Compared with the control group

the ability of cell proliferation transfected with pEGFP-N1-TGF-β1 was decreased significantly (P0.05)

the inhibitory rates were increased from 60% to 80%

the cells cycle were arrested at G

0

/G

1

tage

and the invasive ability were evidently increased (P0.01).    Conclusion   TGF-β1 inhibits the cell proliferation and arrests cell cycle

but increases cell invasion ability in vitro. Its effects may be related to immunosuppression/escape

increased angiogenesis and reinforcement interaction of tumor cells with extracellular matrix.