Proteomic characterization of SAS cells-derived extracellular 2 vesicles in relation to both BPA and neutron irradiation doses

Boron neutron capture therapy (BNCT) is a selective radiotherapy based on nuclear reac-15 tion that occurs when 10B atoms accumulated in cancer cells are irradiated by thermal neutrons, 16 triggering a nuclear fission response leading to cell death. Despite its growing importance in cancer 17 treatment, molecular characterization of its effects is still lacking. In this context, proteomics inves-18 tigation can be useful to study BNCT effect and identify potential biomarkers. Hence, we performed 19 proteomic analysis with nanoLC-MS/MS (liquid chromatography coupled to tandem mass spec-20 trometry) on extracellular vesicles (EVs) isolated from SAS cultures treated or not with 10B-borono-21 phenylalanine (BPA) and different doses of neutron irradiation, to study the cellular response re-22 lated to both boron administration and neutrons action. Although the interference of fetal bovine 23 serum in the medium, we were able to stratify BPA- and BPA+ conditions and to identify EVs-24 derived proteins characterizing pathways potentially related to BNCT effect like apoptosis, DNA 25 repair and inflammatory response. In particular, KLF11, SERPINA1 and SERPINF2 were up-regu-26 lated in BPA+, while POLE and SERPINC1 were up-regulated in BPA-. These results provide the 27 first proteomic investigation of EVs treated with BNCT in different conditions and highlight the 28 potentiality of proteomics for improving biomarkers identification and mechanisms understanding 29 of BNCT.