[HTML][HTML] Addiction of mesenchymal phenotypes on the FGF/FGFR axis in oral squamous cell carcinoma cells

AH Osada, K Endo, Y Kimura, K Sakamoto… - PLoS …, 2019 - journals.plos.org
AH Osada, K Endo, Y Kimura, K Sakamoto, R Nakamura, K Sakamoto, K Ueki, K Yoshizawa…
PLoS One, 2019journals.plos.org
The epithelial–mesenchymal transition (EMT) is a crucial morphological event that occurs
during epithelial tumor progression. ZEB1/2 are EMT transcription factors that are positively
correlated with EMT phenotypes and breast cancer aggressiveness. ZEB1/2 regulate the
alternative splicing and hence isoform switching of fibroblast growth factor receptors
(FGFRs) by repressing the epithelial splicing regulatory proteins, ESRP1 and ESRP2. Here,
we show that the mesenchymal-like phenotypes of oral squamous cell carcinoma (OSCC) …
The epithelial–mesenchymal transition (EMT) is a crucial morphological event that occurs during epithelial tumor progression. ZEB1/2 are EMT transcription factors that are positively correlated with EMT phenotypes and breast cancer aggressiveness. ZEB1/2 regulate the alternative splicing and hence isoform switching of fibroblast growth factor receptors (FGFRs) by repressing the epithelial splicing regulatory proteins, ESRP1 and ESRP2. Here, we show that the mesenchymal-like phenotypes of oral squamous cell carcinoma (OSCC) cells are dependent on autocrine FGF–FGFR signaling. Mesenchymal-like OSCC cells express low levels of ESRP1/2 and high levels of ZEB1/2, resulting in constitutive expression of the IIIc-isoform of FGFR, FGFR(IIIc). By contrast, epithelial-like OSCC cells showed opposite expression profiles for these proteins and constitutive expression of the IIIb-isoform of FGFR2, FGFR2(IIIb). Importantly, ERK1/2 was constitutively phosphorylated through FGFR1(IIIc), which was activated by factors secreted autonomously by mesenchymal-like OSCC cells and involved in sustained high-level expression of ZEB1. Antagonizing FGFR1 with either inhibitors or siRNAs considerably repressed ZEB1 expression and restored epithelial-like traits. Therefore, autocrine FGF–FGFR(IIIc) signaling appears to be responsible for sustaining ZEB1/2 at high levels and the EMT phenotype in OSCC cells.
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