CHARACTERIZATION OF CHOLINERGIC RECEPTORS IN GLIOBLASTOMA CELL LINES

Abstract

Glioblastoma multiforme (GBM) is the most aggressive of the primary brain tumors, characterized by high invasiveness and resistance to traditional treatments. New evidence indicates that GBM cells have a functional cholinergic system, including the ability to produce and release acetylcholine (ACh), as well as the expression of various cholinergic receptors. This research examines the expression and functional role of the cholinergic receptors in glioblastoma cell lines A172 and U87-MG. RT-qPCR-based differential expression of nicotinic receptor subunits demonstrates upregulation of CHRNA9 in U87-MG and moderate expression of CHRNB1 in A172. Measurement of the cell-line differentiated responses to cholinergic stimulation by means of the Fluo-8 AM dye assay showed A172 to have broader calcium influx when subjected to ACh stimulation. In contrast, U87-MG showed prompt, high-amplitude non-universal spikes in cells, mainly in response to choline. Functional assays, such as the analysis of wound healing migration, showed no statistically significant difference in migration kinetics after receptor activation. The results indicate that the cholinergic receptors in GBM are functional and able to mediate calcium signaling, but might not affect cell migration under the conditions of the present experiments, which act as limitations. The results illustrate the complexity of the role of the cholinergic signaling in GBM and call for more specific tools and context-specific research to clarify the role of the latter as a therapeutic target.