FoxM1: a master regulator of tumor metastasis

The FoxM1 transcription factor gene is overexpressed in cancer. Its expression is stimulated by oncogenic signaling pathways and reactive oxygen species. It is also a target of regulation by the tumor suppressor genes. The transcriptional activity of FoxM1 depends upon activation by cyclin and cyclin-dependent kinases as well as Plk1. FoxM1 stimulates expression of several genes involved in the cell cycle progression. Moreover, it supports proliferation of tumor cells by stimulating expression of the antioxidant genes and reducing oxidative stress. A new study provides evidence that FoxM1, in the absence of its inhibitor, the tumor suppressor Arf, drives metastasis of hepatocellular carcinoma (HCC). It induces an epithelial-mesenchymal-like transition phenotype in HCC cells, increases cell migration, and induces premetastatic niche at the distal organ of metastasis. FoxM1 directly activates genes involved in multiple steps of metastasis. In this review, we discuss the evidence for a master regulatory role of FoxM1 in tumor metastasis.