1462 - FGF19 promotes esophageal squamous cell carcinoma progression by inhibiting autophagy

Background

Esophageal squamous cell carcinoma (ESCC) with high mortality is particularly prevalent in China and the prognosis is poor. Although genetic amplification and overexpression of the fibroblast growth factor 19 (FGF19) gene are found in ESCC, mechanisms that contribute to such functional alterations remain elusive.

Methods

Gene-Panel Sequencing was used to detect genetic variants that may be associated with a risk of ESCC. The effect of proliferation inhibition of LY2874455, which is inhibitor of fibroblast growth factor receptors (FGFR), was assessed in ESCC patient-derived cell (PDC) and xenograft (PDX) models. Autophagic activity was evaluated by immunoblotting for microtubule-associated protein 1 light chain 3 (LC3) and p62.

Results

Using Gene-Panel Sequencing of 161 FFPE tissues, we found that FGF19 copy number amplified in almost 30% ESCC. Pharmacological of FGF19/FGFR by LY2874455 significantly induces repression of FGF19 amplificated ESCC progression in either PDC or PDX models. Mechanistic study revealed that treatment with LY2874455 induced activity of autophagy by inhibiting the ERK/MAPK pathway not by AKT pathway.

Conclusions

Our findings reveal that FGF19 amplification inhibits autophagic activity by increasing the phosphorylation level of ERK, which may play an essential role in the pathogenesis of ESCC. Using FGFR inhibitor may represent an effective strategy to suppress FGF19 amplificated ESCC development and progression.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

The authors.

Funding

The Major Project of Health Commission of Zhejiang Province of China (No. WKJ-ZJ-1902), the Public Welfare Technology Foundation of Zhejiang Province of China (No. 2017C34001), Zhejiang high-level innovative talent program, and the 1022 program of Zhejiang Cancer Hospital.

Disclosure

All authors have declared no conflicts of interest.