FGF9/FGFR2 increase cell proliferation by activating ERK1/2, Rb/E2F1, and cell cycle pathways in mouse Leydig tumor cells.

Abstract

Fibroblast growth factor 9 (FGF9) promotes cancer progression; however, its role in cell proliferation related to tumorigenesis remains elusive. We investigated how FGF9 affected MA-10 mouse Leydig tumor cell proliferation and found that FGF9 significantly induced cell proliferation by activating ERK1/2 and retinoblastoma (Rb) phosphorylations within 15 minutes. Subsequently, the expressions of E2F1 and the cell cycle regulators: cyclin D1, cyclin E1 and cyclin-dependent kinase 4 (CDK4) in G1 phase and cyclin A1, CDK2 and CDK1 in S-G2 /M phases were increased at 12 hours after FGF9 treatment; and cyclin B1 in G2 /M phases were induced at 24 hours after FGF9 stimulation, whereas the phosphorylations of p53, p21 and p27 were not affected by FGF9. Moreover, FGF9-induced effects were inhibited by MEK inhibitor PD98059, indicating FGF9 activated the Rb/E2F pathway to accelerate MA-10 cell proliferation by activating ERK1/2. Immunoprecipitation assay and ChIP-quantitative PCR results showed that FGF9-induced Rb phosphorylation led to the dissociation of Rb-E2F1 complexes and thereby enhanced the transactivations of E2F1 target genes, Cyclin D1, Cyclin E1 and Cyclin A1. Silencing of FGF receptor 2 (FGFR2) using lentiviral shRNA inhibited FGF9-induced ERK1/2 phosphorylation and cell proliferation, indicating that FGFR2 is the obligate receptor for FGF9 to bind and activate the signaling pathway in MA-10 cells. Furthermore, in a severe combined immunodeficiency mouse xenograft model, FGF9 significantly promoted MA-10 tumor growth, a consequence of increased cell proliferation and decreased apoptosis. Conclusively, FGF9 interacts with FGFR2 to activate ERK1/2, Rb/E2F1 and cell cycle pathways to induce MA-10 cell proliferation in vitro and tumor growth in vivo.

• Authors: Ming-Min Chang, Meng-Shao Lai, Siou-Ying Hong, Bo-Syong Pan, Hsin Huang, Shang-Hsun Yang, Chia-Ching Wu, H Sunny Sun, Jih-Ing Chuang, Chia-Yih Wang, Bu-Miin Huang
• Journal: Cancer science (Cancer Sci) Vol. 109 Issue 11 Pg. 3503-3518 (Nov 2018) ISSN: 1349-7006 [Electronic] England
• PMID: 30191630 (Publication Type: Journal Article)
• Copyright: © 2018 The Authors. Cancer Science published by John Wiley & Sons Australia, Ltd on behalf of Japanese Cancer Association.

Chemical References

• E2F1 Transcription Factor
• E2f1 protein, mouse
• Fgf9 protein, mouse
• Fibroblast Growth Factor 9
• Retinoblastoma Protein
• Fgfr2 protein, mouse
• Receptor, Fibroblast Growth Factor, Type 2
• Extracellular Signal-Regulated MAP Kinases

Topics

• Animals
• Cell Cycle
• Cell Line, Tumor
• Cell Proliferation
• E2F1 Transcription Factor (metabolism)
• Extracellular Signal-Regulated MAP Kinases (metabolism)
• Fibroblast Growth Factor 9 (metabolism)
• Gene Expression Regulation, Neoplastic
• Leydig Cell Tumor (metabolism)
• Male
• Mice
• Phosphorylation
• Receptor, Fibroblast Growth Factor, Type 2 (metabolism)
• Retinoblastoma Protein (metabolism)
• Signal Transduction
• Testicular Neoplasms (metabolism)