Objective To investigate the role of Cullin1 (Cul1) gene in human breast cancer cel1 migration and invasion and its molecular mechanisms.Methods The Cul1 small interfering RNA (siRNA)was transfected into MDA-MB-231 and BT-549 breast cancer cells.The migration abilities of two breast cancer cel lines were examined by cell migration assay.The invasive abilities were tested by using cell invasion assay.The matrix metalloproteinase (MMPs) activities were detected by using gelatin zymography,and the expression of MMPs and tissue inhibitor of metalloproteinase (TIMPs) proteins was detected by using Western blotting.Results Compared to the control siRNA treatment,Cul1 interference could drastically decreased cell migration abilities of both cell lines by 83％ and 77％,and the cell invasive abilities of both cell lines by 83％ and 77％,respectively.The MMP-2 activity was significantly suppressed after interference of Cul1 in the two breast cancer cell lines by 88％ and 76％,respectively,compared to the control cells.The expression levels of MMP-2 protein were drastically decreased by 88％ and 76％ in the two breast cancer cell lines after Cul1 interference,but TIMP-2 protein expression level was significantly increased by 49.03％ and 68.84％,significantly.Conclusion Silencing Cul1 could suppress human breast cancer cell invasion through up-regulation of TIMP-2 and down-regulation of MMP-2.