FGFR1-induced epithelial to mesenchymal transition through MAPK/PLCγ/COX-2-mediated mechanisms.
Tumour invasion and metastasis is the most common cause of death from cancer. For epithelial cells to invade surrounding tissues and metastasise, an epithelial-mesenchymal transition (EMT) is required. We have demonstrated that FGFR1 expression is increased in bladder cancer and that activation of FGFR1 induces an EMT in urothelial carcinoma (UC) cell lines. Here, we created an in vitro FGFR1-inducible model of EMT, and used this model to identify regulators of urothelial EMT. FGFR1 activation promoted EMT over a period of 72 hours. Initially a rapid increase in actin stress fibres occurred, followed by an increase in cell size, altered morphology and increased migration and invasion. By using site-directed mutagenesis and small molecule inhibitors we demonstrated that combined activation of the mitogen activated protein kinase (MAPK) and phospholipase C gamma (PLCγ) pathways regulated this EMT. Actin stress fibre formation was regulated by PLCγ activation, and was also important for the increase in cell size, migration and altered morphology. MAPK activation regulated migration and E-cadherin expression, indicating that combined activation of PLCγ and MAPK is required for a full EMT. We used expression microarrays to assess changes in gene expression downstream of these signalling cascades. COX-2 was transcriptionally upregulated by FGFR1 and caused increased intracellular prostaglandin E(2) levels, which promoted migration. In conclusion, we have demonstrated that FGFR1 activation in UC cells lines promotes EMT via coordinated activation of multiple signalling pathways and by promoting activation of prostaglandin synthesis.
Section of Experimental Oncology, Leeds Institute of Molecular Medicine, St. James's University Hospital, Leeds, United Kingdom.
Darren C
DC
Tomlinson
Euan W
EW
Baxter
Paul M
PM
Loadman
Mark A
MA
Hull
Margaret A
MA
Knowles
D000199:Actins / Q000378:metabolism; D015153:Blotting, Western; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000502:physiology; D051546:Cyclooxygenase 2 / Q000378:metabolism*; D015232:Dinoprostone / Q000378:metabolism; D004789:Enzyme Activation / Q000235:genetics; D058750:Epithelial-Mesenchymal Transition / Q000502:physiology*; D006801:Humans; D046228:Microarray Analysis; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D016297:Mutagenesis, Site-Directed; D051966:Phospholipase C gamma / Q000378:metabolism*; D060888:Real-Time Polymerase Chain Reaction; D051496:Receptor, Fibroblast Growth Factor, Type 1 / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology*; D019459:Urothelium / Q000378:metabolism*
D000199:Actins; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; C496348:FGFR1 protein, human; D051496:Receptor, Fibroblast Growth Factor, Type 1; D020928:Mitogen-Activated Protein Kinases; D051966:Phospholipase C gamma; D015232:Dinoprostone