Abstract 1165: Vps34 inhibition enhances immunogenicity and immune-mediated killing in MYCN-amplified neuroblastoma

Abstract Neuroblastoma is the most common extracranial solid tumor in children, accounting for approximately 10% of all pediatric cancers and 15% of cancer-related deaths in children under 15 years of age (1). High-risk neuroblastoma, often characterized by MYCN amplification, remains a major therapeutic challenge due to its aggressive behavior and an immunosuppressive tumor microenvironment (TME), which limits the efficacy of current immunotherapies. Based on our previous findings (2), we assessed the therapeutic potential of targeting the autophagy regulator class III phosphatidylinositol 3-kinase (PIK3C3, also known as Vps34) to enhance anti-tumor immunity in high-risk neuroblastoma cells. Transcriptomic analysis on murine MYCN-amplified neuroblastoma cells (NHO2A) treated with two distinct Vps34 inhibitors revealed marked upregulation of the pro-inflammatory chemokines CCL5 and CXCL10, both of which are critical for the recruitment of cytotoxic immune cells into the TME. Gene set enrichment analysis (GSEA) further demonstrated significant enrichment of immune activation, cytokine production pathways and biological oxidations, indicating increased tumor immunogenicity upon Vps34 inhibition. Our preliminary results further suggest that Vps34 inhibition may trigger features consistent with immunogenic cell death (ICD), as treatment with Vps34 inhibitors significantly increased ATP release. Additional ICD markers are currently being investigated. At the functional levels, in vitro co-culture assays demonstrated that Vps34 inhibition enhances CD8+ T cell-mediated cytotoxicity against MYCN-amplified neuroblastoma cells, confirming the immunostimulatory potential of Vps34 targeting. Collectively, our findings underscore the potential of Vps34 inhibition as a promising strategy to render high-risk neuroblastoma cells more susceptible to immune-mediated killing. In vivo studies are currently ongoing to evaluate the therapeutic efficacy of combining Vps34 inhibitors with anti-PD-1 therapy which may pave the way for novel immunotherapeutic approaches for aggressive neuroblastoma. References 1. Colon, N. C., Chung, D. H. (2011). Neuroblastoma. Advances in pediatrics. 2. Noman, M. Z., Parpal, S., Van Moer, K., Xiao, M., Yu, Y., Viklund, J., De Milito, A., Hasmim, M., Andersson, M., Amaravadi, R. K., Martinsson, J., Berchem, G., Janji, B. (2020). Inhibition of Vps34 reprograms cold into hot inflamed tumors and improves anti-PD-1_PD-L1 immunotherapy. Science advances. Citation Format: Elisabetta Bartolini, Teresa L. Ramos, Ruize Gao, Bassam Janji. Vps34 inhibition enhances immunogenicity and immune-mediated killing in MYCN-amplified neuroblastoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 1165.