Abstract LB033: Targeting autophagy in neuroblastoma: Inhibiting VPS34 to enhance anti-GD2 immunotherapy

Abstract Background: Neuroblastoma is the most common childhood extracranial solid tumor, with a 5-year survival rate of approximately 50% in patients diagnosed after 12-15 months of age with high-risk disease. While incorporating anti-GD2 monoclonal antibodies into the treatment of high-risk neuroblastoma has improved patient outcomes, a substantial proportion of patients remain unresponsive or experience disease recurrence. Therefore, there is an urgent need to enhance the efficacy of anti-GD2 immunotherapy by developing new combination regimens. Aims: Given the crucial role of autophagy in promoting tumor cell survival, it emerges as a promising target for cancer treatment. This study aims to investigate the impact of autophagy inhibition via targeting of VPS34, a critical kinase involved in autophagy, on neuroblastoma growth, with a focus on sensitizing tumors to anti-GD2 therapy. Methods: The effects of autophagy inhibition by knocking out essential autophagy genes on tumor growth were assessed in both immunocompromised and immunocompetent mouse models. We evaluated the effects of doxycycline (dox)-inducible VPS34 knockdown and VPS34 inhibitors on neuroblastoma cell survival and spheroid growth in vitro. Additionally, we examined the synergistic anti-neuroblastoma effects of VPS34 inhibition and anti-GD2 monoclonal antibodies using an in vitro NK cell-mediated antibody-dependent cellular cytotoxicity (ADCC) assay and a syngeneic mouse model. The impact of the combination therapy on the tumor microenvironment (TME) was evaluated by flow cytometry. Results: Autophagy inhibition significantly suppressed neuroblastoma tumor growth in vivo, with greater effects in immunocompetent mice compared to immunodeficient mice. Targeting VPS34 resulted in enhanced apoptosis of neuroblastoma cells, decreased spheroid growth in vitro, and a notable reduction in tumor growth in vivo. Importantly, VPS34 inhibition markedly augmented the efficacy of anti-GD2 antibody-mediated tumor suppression by promoting NK cell-mediated ADCC in vitro and fostering an antitumor immune response in the TME in vivo. Conclusion: These preclinical findings suggest that targeting VPS34 represents a promising strategy to improve the antitumor efficacy of anti-GD2 immunotherapy for patients with high-risk neuroblastoma. Citation Format: Jiawen Zhang, Longgui Chen, Yoshinori Takahashi, Hong-Gang Wang. Targeting autophagy in neuroblastoma: Inhibiting VPS34 to enhance anti-GD2 immunotherapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_2):Abstract nr LB033.