EPHA2-dependent Ephrin-B1 signaling supports self-renewal ability and recurrence of oral cancer

As self-renewal of cancer cells is the underlying cause of recurrence and poor prognosis, understanding its molecular determinants is important. Despite the established role of Ephrin-B1 in the regulation of normal stem cells, its role in the self-renewal of cancer cells is poorly explored. Here, using proteomic approach, we report that Ephrin-B1 and its signaling is critical for the self-renewal of oral cancer cells. Further, biochemical analyses revealed that the expression of Ephrin-B1 and EPHA2, a known regulator of cancer stem cells (CSCs), are up-regulated in parallel to the enrichment of self-renewal. Unlike the normal context, as reported, this aberrant upregulation enables their cis -interaction, leading to the phosphorylations of EphrinB1 Y324/329 and Y317. Our in vitro and in vivo functional analyses confirmed the role of Ephrin-B1-EPHA2 signaling in enriching CSCs. Using mouse orthotopic models, we show that abrogation of the ligand, receptor or both results in better prognosis. Moreover, the results of the in silico and immunohistochemical analysis of oral cancer samples reinforced the critical involvement of this signaling in the recurrence of the disease.