gms | German Medical Science

Objective: During the last years, tumor cell communication has been moving forward into the focus of neurooncological research. It has become apparent that glioblastoma can no longer be considered as a proliferating, non-intelligent, abnormal cell collection, but rather as a complex, formed and interacting cellular network. In our study, we aim to explore the different communication pathways and their heterogeneity using novel multi-array technology. Spatial and temporal differences were subsequently mapped and analyzed.

Methods: Electrophysiological mapping based on multi-array electrodes was used to evaluate spatial-temporal differences in cell communication. RNA-sequencing data were acquired from electrophysiological mapped samples and integrated into a network-based analysis. Distinct blocking of ion-channels was performed to identify the responsible ion-flux for membrane depolarization. Patch-clamp of single-cell and cell-cell duplets were used to validate the communication. 4D quantification of simultaneous electrophysiological recordings, immunostainings and transcriptional data were integrated into a computational model.

Results: Mapping of the cell-cell communication in tumor cells, revealed a strong induction of the extracellular Ca2+ flux. This phenomenon was found to be spatially- and temporally heterogeneously distributed within different cell cultures. We, further, used RNA sequencing of cell lines and electrophysiological recordings and analyzed the data within a correlation network. We identified the status of transcriptional differentiation and expression of glioblastoma subgroups highly connected to electrophysiological activity. Highly proliferating, mesenchymal classified cells did not show spontaneous activity in contrast to proneural differentiated cells, that showed a strong activity in basal status and also increased response to glutamate stimulation similar to acquired data from astrocytic cell lines. 4D integration of electrophysiological recordings and immunostaining revealed a spatially differentially expressed CX43 highly associated with electrophysiological activity.

Conclusion: Taken together, our analysis showed a spatial and temporal heterogeneity of cell communication based on Ca2+ flux. This is associated with the transcriptional state of glioblastoma and heterogenic expression of gap-junction protein CX43.