Abstract
The Forkhead box M1 (FOXM1) transcription factor plays crucial roles in the initiation and progression of various malignancies, including hepatocellular carcinoma (HCC). However, the mechanism by which FOXM1 regulates cancer metabolism remains unclear. In the present study, overexpression and RNA interference (RNAi) approaches were used to investigate the role of FOXM1 in the regulation of glycolysis in vitro. Luciferase reporter assays were used to explore the transcriptional regulation of the glucose transporter 1 (GLUT1) promoter by FOXM1. Then, immunohistochemical staining was used to examine the expression of FOXM1 and GLUT1 in 100 paired HCC and adjacent non-cancerous liver tissues. Chi-square test and logistic regression analysis were performed to evaluate the association between FOXM1 and GLUT1 expression with clinicopathological characteristics. Our data showed that FOXM1 promoted glycolysis in the HCC cells. FOXM1 knockdown significantly reduced the expression of GLUT1 among key glycolysis-related molecules in the different HCC cell lines. Glucose uptake and lactate production assay showed that FOXM1 positively regulated glycolysis based on GLUT1 expression. Moreover, FOXM1 overexpression increased and knockdown decreased GLUT1 expression. Luciferase reporter assays showed that the -206 to -199 bp region of the GLUT1 promoter is important for FOXM1 to enhance GLUT1 promoter activity. The results of the IHC analysis showed that the protein expression of FOXM1 and GLUT1 was closely related to the tumor histological grade and TNM stage. In addition, GLUT1 expression was also related to microvascular invasion. In conclusion, overexpression of FOXM1 and GLUT1 may play critical roles in HCC. FOXM1 promotes HCC glycolysis by transactivating GLUT1 expression.