Objective      To overexpress Twist gene in MCF-7 human breast cancer cells and investigate its effect on cancer stem-like cell (CSC) in MCF-7.       Methods      Recombinant plasmid pBABE-puro-myc-Twist was constructed and retrovirus was packaged in HEK293T cells. MCF-7 cells were transfected with the retrovirus carrying Twist gene or the controls. MCF-7/Twist cells and MCF-7/Vector control cells were selected. Mammospheres with characteristics of stem-like cells were collected by long term serum-free suspension cultivation. The expressions of myc-Twist and CSC marker proteins induced by Twist in MCF-7/Twist mammospheres and MCF-7/Vector mammospheres were determined by qRT-PCR and Western blotting. Cell migration was analyzed by Transwell assay.       Results      Twist gene was efficiently delivered into MCF-7 cells

resulting in the stable expression of Twist mRNA. Mammospheres with characteristics of stem-like cells were collected by long term serum-free suspension cultivation. CSC enrichment was enhanced notably in MCF-7/Twist cells (P0.05). The expressions of myc-Twist

Twist and CSC marker proteins SOX2 and OCT4 were upregulated in MCF-7/Twist mammospheres and cell migration was enhanced (P0.05).       Conclusion      Twist plays an important role in enhancing CSC enrichment and promoting cell migration in MCF-7 cells.