Recombinant oncolytic virus NDV-anti-VEGFR2 enhances radiotherapy sensitivity in NSCLC by targeting VEGF signaling and impairing DNA repair.

Resistance to radiotherapy is a significant challenge in the clinical management of non-small cell lung cancer (NSCLC). This study investigates a novel multimodal therapeutic strategy that combines oncolytic Newcastle disease virus (NDV) with an anti-VEGFR2 single-chain variable fragment (NDV-anti-VEGFR2) to enhance radiosensitivity in NSCLC. We engineered NDV-anti-VEGFR2 and assessed its efficacy in sensitizing Calu-1 cells to radiation. In vitro results demonstrated that NDV-anti-VEGFR2 significantly inhibited tumor cell proliferation when combined with radiotherapy. In vivo experiments revealed that NDV-anti-VEGFR2, combined with radiation, achieved a tumor growth inhibition rate of 86.48%, surpassing the effects of NDV or radiation alone. Mechanistic investigations indicated that NDV-anti-VEGFR2 mitigated hypoxia by downregulating HIF-1α and impaired DNA repair pathways, as evidenced by reduced levels of RAD51 and γ-H2AX. These findings suggest that NDV-anti-VEGFR2 not only normalizes tumor vasculature but also enhances the cytotoxic effects of radiation by compromising DNA repair mechanisms. Collectively, our results support the clinical potential of NDV-anti-VEGFR2 combined with radiotherapy as a promising strategy to overcome radiotherapy resistance in NSCLC. Future studies in immunocompetent models are warranted to elucidate the immune-mediated effects of this innovative therapeutic approach.