Eupafolin hinders cross-talk between gastric cancer cells and cancer-associated fibroblasts by abrogating the IL18/IL18RAP signaling axis.

ABSTRACT

BACKGROUND: Cancer-associated fibroblasts (CAFs) are involved in the progression of gastric cancer (GC) as a critical component of the tumor microenvironment (TME), yet specific interventions remain limited. Natural products hold a promising application prospect in the field of anti-tumor in view of their high activity and ease of binding with biological macromolecules. However, the role of natural products in modulating the cross-talk between CAFs and GC cells has not been fully investigated. PURPOSE: The aim of this study was to identify a potential therapeutic target in CAFs and then screen for natural small molecule drugs with anti-tumor activity against this target. METHODS: Integrating bioinformatics analysis of public databases and experimental validation of human samples and cell lines to identify a candidate target in CAFs. Molecular docking and biolayer interferometry technique were utilized for screening potential natural small molecule drugs. The efficacy and underlying mechanisms of the candidates were explored in vitro and in vivo through techniques such as lentiviral infection, cell spheroids culture, immunoprecipitation and cells-derived xenografts. RESULTS: IL18 receptor accessory protein (IL18RAP) was found to be overexpressed in CAFs derived from GC tissues and facilitated the protumor function of CAFs on GC. Based on virtual screening and experimental validation, we identified a natural product, eupafolin, that interfered with IL18 signaling. Phenotyping studies confirmed that the proliferation, spheroids formation and tumorigenesis of GC cells facilitated by CAFs were greatly attenuated by eupafolin both in vitro and in vivo. Mechanistically, eupafolin impeded the formation of IL18 receptor (IL18R) complex by directly binding to IL18RAP, thus blocking IL18-mediated nuclear factor kappa B (NF-κB) activation and reduced the synthesis and secretion of IL6 in CAFs. As a consequence, it inactivated signal transducer and activator of transcription 3 (STAT3) in GC cells. CONCLUSION: This study provides new evidence that IL18 signaling regulates the cross-talk between GC cells and CAFs. And it highlights a novel pharmacological role of eupafolin in inhibiting IL18 signaling, thereby curbing the development of GC via modulating CAFs.