Down-regulation of Forkhead Box M1 Transcription Factor Leads to the Inhibition of Invasion and Angiogenesis of Pancreatic Cancer Cells

Abstract

The Forkhead Box M1 (FoxM1) transcription factor has been shown to play important roles in regulating the expression of genes involved in cell proliferation, differentiation, and transformation. Overexpression of FoxM1 has been found in a variety of aggressive human carcinomas including pancreatic cancer. However, the precise role and the molecular mechanism of action of FoxM1 in pancreatic cancer remain unclear. To elucidate the cellular and molecular function of FoxM1, we tested the consequences of down-regulation and up-regulation of FoxM1 in pancreatic cancer cells, respectively. Using multiple cellular and molecular approaches such as 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, gene transfection, flow cytometry, real-time reverse transcription-PCR, Western blotting, migration, invasion, and angiogenesis assays, we found that down-regulation of FoxM1 inhibited cell growth, decreased cell migration, and decreased invasion of pancreatic cancer cells. FoxM1 down-regulation also decreased cell population in the S phase. Compared with control, FoxM1 small interfering RNA–transfected cells showed decreased expression of cyclin B, cyclin D1, and Cdk2, whereas p21 and p27 expression was increased. We also found that down-regulation of FoxM1 reduced the expression of matrix metalloproteinase-2 (MMP-2), MMP-9 and vascular endothelial growth factor, resulting in the inhibition of migration, invasion, and angiogenesis. These findings suggest that FoxM1 down-regulation could be a novel 1:49 AM 8/29/2007approach for the inhibition of pancreatic tumor progression. [Cancer Res 2007;67(17):8293–300]