Abstract 6394: Patient-derived neuroblastoma models are sensitive to nucleolin-recognizing liposomal drugs

Abstract Background: Neuroblastoma (NB) represents the most frequent and aggressive form of extracranial solid tumor in childhood, causing 15% of cancer mortality. Most of current therapies are extremely aggressive and lack of specific cellular targets, leading to systemic toxicity and drug resistance. Thus, the development of innovative and more specific therapeutic strategies is needed. In this context, we have recently demonstrated that the protein nucleolin (NCL) is expressed on the cell surface of NB cell lines, tumor-associated endothelial cells, NB tissues and bone marrow (BM)-infiltrating NB cells, suggesting it as a target for NB therapy (1). Methods: In this work, a wide panel of Schwannian stroma-poor NB tumors and NB cells derived from NB biopsies, BM-infiltrating NB cells and cells derived from PDX generations of NB, both fresh and after being stored in our local repository, were evaluated for their expression of cell surface NCL by flow cytometry and immunohistochemistry analyses. The antitumor effect of a PEGylated liposomal formulation encapsulating doxorubicin (DXR) and functionalized with the F3 peptide (F3-lipo[DXR]), which specifically recognizes NCL, was tested in vitro towards several NCL-expressing patient-derived tumor spheroids (3D), by using the Cell Titer Glo 3D cytotoxicity assay, and in vivo against PDX models of NB. To confirm the NCL-based selectivity of binding and related antitumor effectiveness, an untargeted PEGylated formulation of DXR (lipo[DXR]) was used. Results: All NB tissues and tumor cells evaluated resulted positive for the expression of cell surface NCL. F3-lipo[DXR] resulted significantly more effective, in terms of reduction of cell viability in the 3D models of all the patient-derived samples, and in terms of tumor growth delay in all PDX models tested, when compared to both untreated mice and those treated with the untargeted lipo[DXR]. F3-lipo[DXR] seem to be more efficacious in those 3D and PDX models expressing higher density of cell surface NCL, further supporting the evidence that NCL mediates the therapeutic effects of NCL-targeted formulation. Other therapeutic experiments on 3D and PDX models of NB are on running. Conclusion: Our results identify nucleolin as putative target also in patient-derived preclinical settings, and pave the way for more in depth investigations in view of a future possible clinical translation. Funding: AIRC IG n. 24397 to PF; CInTech (PRR-30) C644865576-00000005 to LCH, VA and MJN. References 1) Brignole C, et al. J Exp Clin Cancer Res. 2021 Citation Format: Veronica Bensa, Hugo Lopes-Cardoso, Anastasiya Voronovska, Eleonora Ciampi, Giovanna Bianchi, Fabiana Malaguti, Beatrice Gualco, Valerio G. Vellone, Vito A. Lasorsa, Mario Capasso, Michele Cilli, Mirco Ponzoni, Chiara Brignole, Joao N. Moreira, Fabio Pastorino. Patient-derived neuroblastoma models are sensitive to nucleolin-recognizing liposomal drugs [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 6394.