Foxm1 expression in prostate epithelial cells is essential for prostate carcinogenesis

Area of Science:

• Oncology
• Molecular Biology
• Cancer Genetics

Background:

• Advanced prostate cancer (PCa) treatment is challenging.
• Understanding molecular mechanisms of PCa initiation and progression is crucial for developing new therapies.
• The transcription factor Foxm1 is upregulated in PCa but its specific roles in different cell types are unknown.

Purpose of the Study:

• To determine the role of Foxm1 in prostate tumor cells during PCa development.
• To investigate Foxm1's function in regulating tumor cell proliferation, metastasis, and angiogenesis.
• To identify direct transcriptional targets of Foxm1 in PCa.

Main Methods:

• Generated transgenic mouse models with gain- and loss-of-function of Foxm1 driven by the Probasin promoter.
• Utilized the TRAMP model of PCa.
• Analyzed tumor growth, metastasis, proliferation, angiogenesis, gene expression (Cdc25b, Cyclin B1, Plk-1, Lox, Versican, Vegf-A, 11β-Hsd2), and performed promoter activity assays.

Main Results:

• Loss of Foxm1 in prostate epithelial cells reduced PCa tumor growth and metastasis in TRAMP mice.
• Decreased proliferation, angiogenesis, and downregulation of key genes (Cdc25b, Cyclin B1, Plk-1, Lox, Versican, Vegf-A) were observed in Foxm1-deficient tumors.
• Foxm1 directly targets and activates the 11β-Hsd2 promoter, an enzyme important for tumor cell proliferation.

Conclusions:

• Foxm1 expression in prostate epithelial cells is critical for prostate carcinogenesis.
• Inhibition of Foxm1 is a potential therapeutic strategy for prostate cancer.
• Foxm1 regulates key genes involved in cell proliferation, metastasis, and angiogenesis in PCa.