Purpose: The present study was to investigate the clinicopathologic significance and potential role of FOXC2 in the progression of colorectal cancer (CRC).
Methods: The relationship between FOXC2 expression and clinical characteristics of CRC was analyzed in 205 paraffin-embedded archived CRC specimens by immunohistochemistry (IHC).
The effects of FOXC2 on EMT, migration and invasion, as well as on metastasis, were examined both in vitro and in vivo, using Western bot, immunofluorescent staining and migration assay and experimental metastasis assay in nude mice. Western blot and immunofluorescent staining were performed to examine the impact of FOXC2 on the PI3K/Akt, MAPK and Wnt/b-Catenin signaling pathways. TOP/FOP luciferase assay was using to detect Wnt/b-Catenin signaling acitvity changes under expression of FOXC2.
Results: FOXC2 protein level was significantly correlated with advanced Dukes stage (P=0.036), N stage (P=0.013), distant metastasis (P=0.001), and poor survival of patients (P=0.005). Enforced expression of FOXC2 induced a EMT-like phenotype in SW480 cells, enhanced cell migration in vitro and metastasis in vivo. Conversely, knockdown of FOXC2 caused an increased expression of epithelial markers and decreased expression of mesenchymal markers, accompanied by inhibition effects of cell migration in vitro and metastasis in vivo. Overexpression of FOXC2 upregulated p-AKT, p-GSK3b, and p-ERK, while silence of FOXC2 downregulated p-AKT, p-GSK3b, and p-ERK. Additionally, TOP/FOP luciferase acitvity was dramaticly increased in cells overexpressing FOXC2. Moreover, overexpression of FOXC2 significantly promoted the nuclear b-Catenin expression, which indicate that the Wnt/b-Catenin signaling pathway was activited. Thus, these results suggested that FOXC2 could enhance PI3K/AKT, MAPK and Wnt/b-Catenin pathway activities in CRC cells.
Conclusions: Our findings suggest that FOXC2 protein, as a valuable marker of CRC prognosis, plays an important role in the progression of human CRC.