Expression and significance of FoxM1 in esophageal squamous cell carcinoma cells in vitro and in vivo

To investigate the expression and significance of FoxM1 in esophageal squamous cell carcinoma (ESCC) cell lines and tissues.Western blot assay was used to detect the expression of FoxM1 in human esophageal epithelial cells and esophageal squamous cell cancer cell lines TE1, TE10, TE11 and Eca109 cells. To determine whether down-regulation of FoxM1 expression could inhibit the aggressive phenotype of ESCC cells, we knocked down the expression of FoxM1 by using FoxM1-shRNA in TE1 cells. Then we detected the cell proliferation, migration and invasion of TE1 cells by MTT assay, scratch assay and transwell assay. Furthermore, the effect of FoxM1 knockdown on tumorigenicity in nude mice was evaluated. Finally, immunohistochemical staining was used to detect the expression of FoxM1 in 99 cases of ESCC tissues and adjacent normal esophageal tissues. χ(2) test was used to analyze the correlations between the expression of FoxM1 and clinicopathologic characteristics and prognosis of ESCC patients.Western blot data showed that FoxM1 expression was lower in normal esophageal epithelial cells and highly expressed in four esophageal cancer cell lines, especially in TE1 cells. Knockdown of FoxM1 inhibited the growth, invasion and migration of TE1 cells and reduced their tumorigenicity in nude mice.The positive expression rate of FoxM1 in ESCC was 61.6% (61/99), significantly higher than that in the paired adjacent normal tissues (24.2%, 24/99) (P<0.05). The positive expression rate of FoxM1 in ESCC tissues was 61.6% (61/99), significantly higher than that in the paired adjacent normal tissues (24.2%, 24/99) (P<0.05). FoxM1 expression was significantly and positively correlated with lymph node metastasis, clinical stage and invasive depth (P<0.05). The median survival time was 42.3 months in 38 cases of patients with negative FoxM1 expression, and 33.0 months in 61 cases of positive FoxM1 expression, and the difference was statistically significant (P=0.036).FoxM1 is highly expressed in ESCC, and significantly correlated with the initiation, development and prognosis of esophageal cancer. FOXM1 might be an indicator to predict the prognosis and serve as a potential target for therapy in esophageal cancer.