Hepatocyte growth factor activates Wnt pathway by transcriptional activation of LEF1 to facilitate tumor invasion

Hepatocyte growth factor (HGF) is a secretory protein that plays important roles in cancer growth and metastasis. Lymphoid-enhancing factor 1 (LEF1) is a transcription factor mediating Wnt/β-catenin signaling. Using microarray analysis, we found HGF induced expression of LEF1 in liver and breast cancer cell lines. HGF induced expression of LEF1 through phosphatidylinositol 3-kinase/Akt and nuclear factor-kappa B (NF-B) signaling. Multiple NF-B-binding sites were mapped within 3 kb upstream of LEF1 transcription initiation site. NF-B binding to a site 2 kb upstream of LEF1 transcription initiation site was confirmed by chromatin immunoprecipitation assay. Knockdown of LEF1 inhibited the expression of Slug and Zinc finger E-box-binding homeobox 2 (ZEB2) and markedly attenuated HGF-induced tumor migration and invasion. Using immunohistochemical staining, we found LEF1 was frequently expressed in multiple types of carcinoma but not in the non-tumorous epithelial cells. Our finding suggest that transcriptional activation of LEF1 is a mechanism of cross talk between HGF/c-Met and Wnt/β-catenin pathways and is essential for HGF-induced tumor invasion.