%0 Generic
%A Lokumcu, Tolga
%C Heidelberg
%D 2023
%F heidok:32720
%R 10.11588/heidok.00032720
%T Metabolic, proteomic, transcriptomic, and fatty acid profiling of glioblastoma stem cells and their small extracellular vesicles
%U https://archiv.ub.uni-heidelberg.de/volltextserver/32720/
%X Glioblastoma is the most frequent and lethal brain tumor, showing a high degree of intra- and intertumoral  heterogeneity. Despite the multimodal treatments (surgical resection, irradiation, and chemotherapy),  overall survival of patients is still less than 15 months. The inevitable relapse of glioblastoma is mainly  attributed to the subpopulation of tumor initiating cells, namely glioblastoma stem cells, which are shown  to be refractory to standard treatments. The exceedingly heterogeneous nature of glioblastoma creates  hurdles in developing effective therapies and makes it extremely difficult to eradicate. This project  investigated the role of GSCs-derived sEVs in glioblastoma aggressiveness with the particular focus on  the complexity of tumor-derived sEVs in terms of proteins, metabolites, fatty acids, and small RNAs. In  this direction, protein, metabolite, fatty acid, and small-RNA contents of sEVs and their parent cells  (NCH421k, NCH644, NCH705, and NCH711d) were profiled by utilizing mass spectrometry and highthroughput  sequencing. Protein profiling of sEVs and their respective cell lines revealed the enrichment  of proteins playing a role in amino acids, carboxylic acids, and organic acids transmembrane transport,  together with the ones functioning in growth factor binding (including insulin-like growth factor I and  transforming growth factor beta). In line with the proteomic analysis, metabolite screening of GSCderived  sEVs also displayed the existence of metabolites associated with alanine, aspartate, glutamate  metabolism, arginine biosynthesis, and butanoate metabolism, suggesting the dual role of GSCs-derived  sEVs, which is transferring proteins responsible for the transport of amino acids/carboxylic acids and  providing metabolites that will be used in amino acid and carboxylic acid metabolism. In conjunction with  proteomic and metabolic analysis, profiling of fatty acids (carboxylic acids with long aliphatic chains) has  revealed the presence of different fatty acid species, especially saturated fatty acids, in GSCs-derived  sEVs, further implying that loading of biological cargos into sEVs is a highly regulated process, and that  GSCs-derived sEVs are important sources for tumor cells to maintain their cellular metabolism. Finally,  small RNA sequencing of GSCs-derived sEVs and their parent cells was carried out to shed some light  on the contribution of sEVs-derived small RNAs to heterogeneity of glioblastoma; however, due to  technical problems in sequencing (very low reads counts, poor complexity of sequencing library) the data  is unfortunately not reliable for comparative analysis.  In summary, this project revealed the complexity of GSCs-derived sEVs in terms of proteins, metabolites,  fatty acids, and smRNAs (with limited degree), and unveiled their potential contribution to tumor  heterogeneity and critical cellular processes commonly deregulated in glioblastoma.