Observationof Acetylcholine Secretion on Living GlioblastomaCells

Glioblastoma, as the most common malignant brain tumor in humans, remains a big societal challenge; identifying new signaling molecules in glioblastoma opens avenues for alternative treatment strategies. Emerging evidence suggests that neurochemical signaling is involved in glioblastoma pathology. However, it is unknown if the neurotransmitter acetylcholine can be secreted by glioblastoma cells despite the expression of the acetylcholine synthesis enzyme. Here, we tested our hypothesis that glioblastoma cells secreted acetylcholine using a nanoelectrochemistry platform: scanning electrochemical microscopy (SECM) and nanoelectrodes. Linear and selective acetylcholine detection was achieved on the nano interface between two immiscible electrolyte solutions (nanoITIES, also called liquid/liquid interface). Using SECM, we positioned the acetylcholine-sensing nanoITIES electrodes very close (i.e., hundreds of nanometers) to the living T98G glioblastoma cells. We observed real-time secretion of acetylcholine from glioblastoma cells. We quantified the number of secreted acetylcholine molecules. Our discovery that glioblastoma cells secrete acetylcholine reveals a novel signaling axis in glioblastoma biology, highlighting a potential therapeutic target for glioblastoma treatment.