Dual targeting of EphAs and KDR axis hampers VEGF-induced angiogenesis and glioma stem cell replication

Glioblastoma multiforme (GBM) is an aggressive and highly vascularized brain tumor with a poor prognosis and limited therapeutic options. Resistance to current treatments is largely driven by glioma stem-like cells (GSCs), a subpopulation with high tumorigenic potential that plays a key role in tumor progression, recurrence, and angiogenesis. Eph receptor tyrosine kinases, including EphA and EphB, are broadly implicated in GBM biology. While both classes contribute to tumor development and plasticity, EphA receptors are more directly involved in GSC maintenance and in crosstalk with the VEGF/VEGFR-2 axis, whereas EphB receptor dysregulation may promote tumor invasion. This subclass distinction makes selective targeting of EphA receptors an attractive therapeutic strategy. Here, we present the characterization of UniPR1449, a novel selective EphA receptor inhibitor. UniPR1449 is a protein–protein interaction inhibitor (PPI-i) that blocks ephrin-A1-induced EphA2 phosphorylation, internalization, and degradation in GBM cell lines. In patient-derived GSCs, the compound significantly reduces proliferation and S-phase entry. Additionally, UniPR1449 impairs VEGF-induced angiogenesis in the chick chorioallantoic membrane (CAM) assay, while leaving FGF2-mediated vascularization unaffected. This dual mechanism of action—targeting both EphA signaling and VEGFR-2-mediated angiogenesis—highlights its therapeutic potential in addressing two key pathological features of GBM: vascular support and stem-like tumor cell renewal. Moreover, the selectivity displayed by UniPR1449 for EphA receptors may offer a safety advantage over pan-Eph inhibitors, which could disrupt physiological EphB functions. Together, these results position UniPR1449 as a promising lead compound for the development of multitarget therapies against GBM.