FGF1–FGFR1 axis promotes tongue squamous cell carcinoma (TSCC) metastasis through epithelial–mesenchymal transition (EMT)

Abstract

Increasing evidences suggest a close association between tumor metastasis and the inflammatory factors secreted by tumor microenvironment. It has been reported that epithelial mesenchymal-transition (EMT) plays a significant role during multiple types of tumor metastasis and progression induced by inflammatory factor from tumor microenvironment. Previous researches implied that fibroblast growth factor 1 (FGF1) can promote tumor progression and cause poor prognosis in several types of malignant tumors via interacting with its receptor fibroblast growth factor receptor 1 (FGFR1). However, the effects of FGF1–FGFR1 on tongue squamous cell carcinoma (TSCC) are not yet completely understood. In the present study, we evaluated the effects and function of FGF1–FGFR1 axis on TSCC metastasis. In addition, we investigated whether the EMT pathway is involved in these effects, thus modulating the TSCC progression. The expression of FGFR1 was measured both in tongue cancer cell lines and tissues by qRT-PCR and western blot. We found that FGFR1 was up-regulated in TSCC tissues compared to non-neoplastic tongue tissues. Additionally, overexpression of FGFR1 is positively associated with poor differentiation and metastasis potential. Furthermore, the function of FGF1–FGFR1 was examined in TSCC cell line. The results implied that FGF1 can obviously promote Cal27 cells migration and invasion abilities through FGFR1, while the motile and invasive capabilities can be severely attenuated when knockdown the expression of FGFR1 by specific siRNAs. Further investigation results show that FGF1–FGFR1 axis promotes TSCC metastasis by modulating EMT pathway. However, this effect can be inhibited by blocking the FGF1–FGFR1 axis using FGFR1 specific siRNAs. In conclusion, our findings of the present study provide the evidences that FGF1–FGFR1 axis promotes the TSCC metastasis through the EMT pathway.