Small Extracellular Vesicles Secreted by Cisplatin-Resistant Neuroblastoma Cells Increase Lactate Secretion and Alter Metabolic Pathways in Primary Human Umbilical Vein Endothelial Cells (HUVECs)

Chemoresistance, particularly to cisplatin, remains a significant challenge in treating high-risk neuroblastoma, resulting in a mere 20% five-year overall survival rate. Recent evidence suggests that tumour-derived small extracellular vesicles (sEVs) play a crucial role in cancer progression by promoting angiogenesis, invasion, and proliferation in recipient cells. This study investigated the alterations in the protein cargo of sEVs secreted by cisplatin-resistant neuroblastoma cells and their impact on reprogramming non-cancerous recipient cells, with a focus on angiogenesis. We utilised an in vitro model of cisplatin-resistant neuroblastoma (KellyCis83) paired with its cisplatin-sensitive parental cell line (Kelly). Functional enrichment analysis of the sEV proteome identified metabolism as a key dysregulated pathway in KellyCis83 sEVs. Notably, sEVs from drug-resistant KellyCis83 cells significantly increased the basal oxygen consumption rate and tubule formation in human umbilical vein endothelial cells (HUVECs) compared to Kelly's sEVs. The angiogenic potential of both Kelly and KellyCis83 sEVs was assessed using cell proliferation, migration, and tube formation assays. We observed that sEV uptake by HUVECs is energy-dependent and slows cell proliferation when cultured in media lacking angiogenic factors (VEGF, IGF-1, and b-FGF), likely due to increased anchorage-dependent differentiation of HUVECs. This study demonstrates a potential mechanism by which sEVs derived from cisplatin-resistant neuroblastoma cells modulate endothelial cell function through alterations in metabolic pathways. These findings provide new insights into the role of sEVs in chemoresistance and angiogenesis in neuroblastoma, potentially opening avenues for novel therapeutic strategies.