Mechanistic insights into NET1–UNC5B complex formation and Its targeted disruption by NP137 fab and NET1 peptide competitors

Netrin‑1, a secreted protein initially characterized for its role in axon guidance, has emerged as a critical mediator of cancer progression. Preclinical studies with the anti‑netrin‑1 antibody NP137, which blocks the netrin‑1–UNC5B interaction, have demonstrated reactivation of tumor suppressor functions and sensitization of cancer cells to chemotherapy. Here, we identified the molecular binding interface of the netrin‑1–UNC5B complex using integrative structural and quantitative biophysical analyses. We then determined how NP137 binding inhibits this interaction by sterically blocking key contact points within the interface. Guided by these mechanistic insights, we rationally designed peptides that disrupt the netrin‑1–UNC5B complex through interfering with heparin-mediated stabilization of the complex by binding to shared heparin-binding sites. This comprehensive structural and mechanistic analysis advances understanding of netrin‑1 signaling and establishes strategies for therapeutic intervention in netrin‑1-driven malignancies. Netrin-1 signaling controls cell fate and is a key target in cancer research. Here, authors describe the structural basis of netrin-1–UNC5B signaling and study how antibody and peptide inhibitors disrupt this interaction