WYC-209 suppresses gastric cancer by down-regulating FGF18 via inactivating the STAT3 signaling pathway.

[BACKGROUND] Gastric cancer (GC) is regarded as a major health burden all over the world. WYC-209 inhibits the growth and metastasis of tumor-repopulating cells (TRCs). However, its effectiveness on GC was unexplored. Herein, this study aims to investigate the effect of WYC-209 on GC and elucidate its underlying mechanism.

[METHODS] We examined the effects of WYC-209 on cell survival, migration, invasion, and colony-forming capacities of two GC cell lines (AGS and HGC-27). Subsequently, RNA-seq and enrichment analyses were performed to screen the differentially expressed genes (DEGs) and the enriched signaling pathways. To further explore the underlying mechanism, loss- and gain-function experiments, Chromatin immunoprecipitation, and luciferase reporter were conducted. Finally, xenograft models were constructed to examine the effects of WYC-209 in vivo.

[RESULTS] WYC-209 significantly inhibited cell motility in vitro and tumor growth in vivo. RNA-seq performed in AGS cells after WYC-209 treatment revealed that the inhibition effect of WYC-209 on GCs may be associated with the down-regulation of fibroblast growth factor-18 (FGF18), and pleasantly, FGF18 overexpression abrogated the suppression effect of the drug. In addition, we found that WYC-209 attenuated the activation of the Signal Transducer and Activator of Transcription 3 (STAT3) signaling pathway, and impeded the FGF18 levels expressed in GCs. Importantly, the WYC-209 treatment circumvented the binding of STAT3 to the FGF18 promoter, suggested that WYC-209 down-regulated FGF18 expression via the STAT3 signaling pathway.

[CONCLUSION] Together, our findings presented the promise of WYC-209 in suppressing GC by down-regulating FGF18 expression through inactivating the STAT3 signaling pathway.