CD93 Blockade Overcomes Sunitinib Resistance in Pancreatic Neuroendocrine Tumors.

Pancreatic neuroendocrine tumors (PanNETs) are rare malignancies of the pancreas, but their incidence is steadily increasing. Standard therapy with antiangiogenic inhibitors, including sunitinib, has shown clinical benefit for advanced PanNETs; however, its long-term effectiveness is limited due to the development of resistance. In this study, we demonstrate that targeting the CD93-IGFBP7 axis enhances the efficacy of sunitinib by normalizing tumor vasculature in PanNETs. Both CD93 and its ligand IGFBP7 are enriched in the tumor microenvironment (TME) of PanNETs. Disrupting the CD93/IGFBP7 interaction with monoclonal antibodies (mAbs) in RIP1-Tag2 mice normalizes tumor vasculature to inhibit tumor progression and metastasis. Combining anti-CD93 mAb and sunitinib synergistically slows tumor growth and improves survival. Mechanistically, CD93 blockade mitigates sunitinib-induced tumor hypoxia and invasiveness, preventing the upregulation of proangiogenic factors. Critically, anti-CD93 mAb treatment prolongs survival in RIP1-Tag2 mice with late-stage, sunitinib-resistant PanNETs. Our results support CD93 blockade as a promising therapeutic approach for advanced PanNETs.