Abstract 6561: Extracellular vesicles-derived nucleolin as a novel biomarker in neuroblastoma patients

Background: Neuroblastoma (NB) represents the most frequent form of extracranial solid tumor of children, responsible for 15% of childhood cancer deaths. Recently, cell surface Nucleolin (NCL) was suggested as a target for NB therapy and its expression at RNA level was validated as an independent (adjusting for age, INSS stage, and MYCN status) prognostic marker for NB. Extracellular vesicles (EVs) may express different surface proteins derived from the parental cells. Liquid biopsy-derived EVs from NB patients might reveal a possible diagnostic/prognostic role of NCL at the protein level. Methods: Here we evaluated the expression of small EVs (sEVs)-derived NCL in the peripheral bloods (PB) of low risk- (LR) and high risk- (HR) NB patients at onset and in relapse, and of aged-matched controls (CTRs). PB were firstly centrifuged at 400 g for 10 min at 4°C, then the supernatant was re-centrifuged at 1600 g for 10 min at 4°C to collect plasma. Isolation of EVs was performed from 500 μl of plasma through ultracentrifugation at 20.000 g to remove large EVs and secondly at 100.000 g to isolate sEVs. sEVs were characterized in term of size distribution by using Nano Traking Analysis (NTA). Twenty μg of sEVs-derived proteins were used in Western Blot analysis to evaluate the expression of the EVs markers as well as NCL. Results: The isolated CD63- and CD9-expressing sEVs range in size between 81.6 and 138.7 nm. Interestingly, particles concentration results significantly higher in the PB derived from HR-NB, both at onset and at relapse, compared to that from both CTR and LR-NB patients. Furthermore, we have found a higher NCL protein expression on sEVs derived from the PB of all NB patients, compared to that derived from CTR. Noteworthy, NCL expression results significantly higher in the sEVs derived from HR-NB patients at onset, compared to that observed in LR-HR patients, suggesting a potential prognostic value of sEVs-derived NCL in clinic. Conclusion: The extracellular vesicles-derived protein nucleolin in the peripheral blood of patients may represent a prognostic factor for neuroblastoma. Funding: AIRC IG n. 24397 to PF Citation Format: Veronica Bensa, Danilo Marimpietri, Martina Morini, Martina Ardito, Eleonora Ciampi, Martina Fragola, Massimo Conte, Alberto Garaventa, Joao N. Moreira, Xhuliana Kajana, Alessandro Garbarino, Gino Tripodi, Roberto Bandettini, Giovanni Candiano, Mirco Ponzoni, Chiara Brignole, Fabio Pastorino. Extracellular vesicles-derived nucleolin as a novel biomarker in neuroblastoma patients [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 6561.