ST2L promotes VEGFA-mediated angiogenesis in gastric cancer by activating TRAF6/PI3K/Akt/NF-κB pathway via IL-33

Suppression of Tumorigenicity 2 (ST2) is a member of the interleukin-1 receptor/ Toll-like receptor superfamily, and its specific ligand is Interleukin-33 (IL-33). IL-33/ ST2 signaling has been implicated in numerous inflammatory and allergic diseases, as well as in promoting malignant behavior of tumor cells and angiogenesis. However, the precise role of ST2 in gastric cancer angiogenesis remains incompletely elucidated. We observed a significant correlation between high expression of ST2 in gastric cancer tissues and poor prognosis, along with various clinicopathological features. In vitro experiments demonstrated that the IL-33/ ST2 axis activates the PI3K/AKT/NF-κB signaling pathway through TRAF6, thereby promoting VEGFA-mediated tumor angiogenesis; meanwhile sST2 acts as a decoy receptor to regulate the IL-33/ST2L axis. Consistent findings were also observed in subcutaneous xenograft tumor models in nude mice. Furthermore, we investigated the molecular mechanism by which IL-33 promotes ST2L expression in GC cells via upregulation of transcription factors YY1 and GATA2 through intracellular signaling pathways.