Background

Fibroblast growth factors (FGFs) signal by binding to FGF receptors (FGFRs), eliciting a diverse range of cellular responses. FGFR mutations are frequently found in endometrial cancer and may be a driving force in tumorigenesis. We are characterizing endometrial cancer cell lines containing common FGFR2 mutations and assessing their effects on cellular transformation.

Method

Three endometrial cancer cell lines, containing at least one common FGFR2 mutation, were selected. FGF and FGFR isoform expression and downstream signalling was established using 2D culture and further assessed in a 3D organotypic model. We are also investigating the role of FGFR2 mutations in endometrial cancer using a zinc finger nuclease approach, allowing us to investigate mutant FGFR2 constructs in immortalized endometrial cells under the control of the endogenous FGFR2 promoter. FGFR2 mutations will also be reversed in endometrial cancer cells and signalling impact assessed using mass spectrometry.

Results

FGFR2c and its ligand, FGF2, were expressed strongly in all cell lines. ERK phosphorylation increased upon stimulation with FGF2, indicative of MAP Kinase pathway activation. This was abolished by an FGFR inhibitor. Treatment with FGF7, specific to FGFR2b, and FGF10, which binds both FGFR1b and FGFR2b with highest affinity, had no effect on ERK phosphorylation. FGFR2 amplification in cancer cell lines was established through western blot and PCR analysis. Initial 3D culture data indicate endometrial cancer cells do not invade into the stroma. However, decreased cell proliferation and increased apoptosis are evident when organotypic cultures are treated with an FGFR inhibitor.

Conclusion

High levels of FGFR2c in these epithelial cell lines indicates receptor class switch from FGFR2b, resulting in increased proliferation and survival, perhaps via autocrine stimulation. Organotypic data suggest that inhibition of FGF signalling leads to cell death in endometrial cancer cells.