Abstract: In order to establish a method for visualizing FOXM1 expression in cells, a lentiviral plasmid (Lv-PromoterFOXM1-GFP) was constructed by the genetic engineering method, which carried the 1.2 kb FOXM1 promoter region and the green fluorescent protein (GFP) gene. The constructed Lv-PromoterFOXM1-GFP was cotransfected with packaging plasmids Δ8.91 and PVSVG into HEK293T cells to produce live lentivirus and infecting human breast cancer cell line， MDA-MB-231 cells， the flow cytometry was used to detect the GFP signal of MDA-MB-231 cells， and the result indicated that the lentivirus infection was successful. Lv-PromoterFOXM1-GFP infected MDA-MB-231 cells were subjected to flow sorting according to the GFP signal to obtain a GFP-High cell subpopulation and GFP-Low cell subpopulation. The FOXM1 protein levels between two obtained FOXM1-Low and FOXM1-High cell subpopulation samples were detected by Western Blot, and it was confirmed that GFP expression was in accordance with FOXM1 expression. Isolating the FOXM1 highly expressed cancer cells and poorly expressed cancer cells could provide research materials for studying the function of FOXM1 in the development of breast cancer.

Key words: promoter tracer system, lentivirus vector, FOXM1, breast cancer cell MDA-MB-231