FOXM1 promotes the epithelial to mesenchymal transition by stimulating the transcription of Slug in human breast cancer

The Forkhead Box M1 (FOXM1) transcription factor is involved in tumorigenesis and tumor progression in multiple human carcinomas. In this study, we found that FOXM1 promoted the epithelial to mesenchymal transition (EMT) in human breast cancer. We observed a strong correlation between the expression levels of FOXM1 and the mesenchymal phenotype. Knockdown of FOXM1 inhibited the mesenchymal phenotype, whereas stable overexpression of FOXM1 induced EMT in breast cancer cells. FOXM1 was found to endogenously bind to and stimulate the promoter of Slug that is crucial for EMT progression. The knockdown of Slug abolished the EMT-inducing function of FOXM1. The stable overexpression of FOXM1 promoted metastasis of breast cancer cells in vivo. This study confirmed that FOXM1 promoted EMT in breast cancer cells by stimulating the transcription of EMT-related genes such as Slug.