Abstract: Objective To investigate the effect of overexpressed-integrin beta 1 (ITGB1)gene on epithelial-mesenchymal transition (EMT) and cell migration in breast epithelial cell lineMCF10A. Methods Recombinant plasmid pBABE-puro-myc-ITGB1 was constructed and retrovirus was packaged in HEK293T cells. MCF10A cells were transfected with the retrovirus carrying ITGB1 gene or the controls. Blank group(MCF10A), negative control group(MCF10A-vector), ITGB1overexpression group(MCF10A-ITGB1)were set up. After treatment with puromycin 3days, the expression of ITGB1in MCF10A cells was determined by quantitative real-time PCR and Western blot assays. The ability of migration and invasion were analyzed by Transwell assays. The expression of epithelial-mesenchymal transition (EMT) marker proteins (E-cadherin，vimentin，fibronectin and N-cadherin) and ITGB1 downstream proteins (ILK, p-FAK and FAK) in MCF10A cells were detected by Western blotting. Results ITGB1 gene was successfully delivered into MCF10A cells, resulting in the stable expression of ITGB1 mRNA and protein.Compared with MCF10A and MCF10A-vector cells, the ability of migration and invasion were enhanced notably in MCF10A-ITGB1 cells (p<0.05). The expression of the epithelial marker E-cadherin protein was down regulated (p<0.01), the mesenchymal marker proteins (vimentin，fibronectin and N-cadherin) and ITGB1 downstream proteins(ILK and p-FAK)were upregulated in MCF10A-ITGB1 cells (p<0.01). Conclusions ITGB1 induces EMT and promotes cell migration and invasion in breast epithelial cell line MCF10A.

Key words: ITGB1, EMT, cell migration, cell invasion