Fork Head Box M1 Regulates Vascular Endothelial Growth Factor-A Expression to Promote the Angiogenesis and Tumor Cell Growth of Gallbladder Cancer

Background: Gallbladder cancer (GBC) is an aggressive type of biliary tract cancer that lacks effective therapeutic targets. Fork head box M1 (FoxM1) is an emerging molecular target associated with tumor progression in GBC, and accumulating evidence suggests that vascular endothelial growth factor (VEGF) promotes various tumors by inducing neoangiogenesis.

Aim: To investigate the role of FoxM1 and the angiogenesis effects of VEGF-A in primary GBC.

Methods: Using immunohistochemistry, we investigated FoxM1 and VEGF-A expression in GBC tissues, paracarcinoma tissues and cholecystitis tissues. Soft agar, cell invasion, migration and apoptosis assays were used to analyze the malignant phenotype influenced by FoxM1 in GBC. Kaplan-Meier survival analysis was performed to evaluate the impact of FoxM1 and VEGF-A expression in GBC patients. We investigated the relationship between FoxM1 and VEGF-A by regulating the level of FoxM1. Next, we performed MTT assays and Transwell invasion assays by knocking out or overexpressing VEGF-A to evaluate its function in GBC cells. The luciferase assay was used to reveal the relationship between FoxM1 and VEGF-A. BALB/c nude mice were used to establish the xenograft tumor model.

Results: FoxM1 expression was higher in GBC tissues than in paracarcinoma tissues. Furthermore, the high expression of Foxm1 in GBC was significantly correlated with a malignant phenotype and worse overall survival. Meanwhile, high expression of FoxM1 influenced angiogenesis; high expression of FoxM1 combined with high expression of VEGF-A was related to poor prognosis. Attenuated FoxM1 significantly suppressed cell proliferation, transfer and invasion . Knockdown of FoxM1 in GBC cells reduced the expression of VEGF-A. Luciferase assay showed that FoxM1 was the transcription factor of VEGF-A, and knockdown VEGF-A in FoxM1 overexpressed cells could partly reverse the malignancy phenotype of GBC cells. In this study, we found that FoxM1 was involved in regulation of VEGF-A expression.

Conclusion: FoxM1 and VEGF-A overexpression were associated with the prognosis of GBC patients. FoxM1 regulated VEGF-A expression, which played an important role in the progression of GBC.