Abstract A058: Dielectric characterization of glioblastoma cancer stem cells
Authors: Bortolozzi Roberta , Mariotto Elena , Rampazzo Elena , Porcù Elena , Saada Sofiane , Provent Thomas , Lalloué Fabrice , Pothier Arnaud , Viola Giampietro , Persano Luca 
Published: March 2020

Abstract
Glioblastoma (GBM) is the most aggressive type of primary brain tumor, characterized by the intrinsic resistance to chemotherapy due to the presence of a highly aggressive Cancer Stem Cell (CSC) sub-population. The coexistence in the same mass of bulk and CSCs stuck at different stages of differentiation and genetic backgrounds prevents counteracting all cells with single treatments. Through the application of a Dielectrophoretic force (DEP) we provide a successful CSC isolation from a mixed cell population, exploiting their physical properties. Using FACS, the expression of specific stem cell and differentiation markers (CD133, Nestin, Sox1, Sox2, GFAP, Doublecortin (DCX) and Ki67) were analyzed in 17 primary cell lines of GBM. CD133 expression was also exploited as a reliable marker for the identification of the CSC subpopulation and thus used for sorting CD133+ and CD133- GBM primary cells by flow cytometry techniques. CD133+ and CD133- cells were characterized for their ability to self-renew and form neurospheres. In all experiments, CD133+ cells have shown a significant increased efficiency of neurosphere generation that was accompanied by a higher self-renewal potential as measured by the limiting dilution assay (LDA) in vitro. The characterization and isolation of patient-derived GBM cells by FACS allowed constituting a cell library with three distinct cell subpopulation types: CD133+/CD133-/Total population, that have been characterized for their specific Electromagnetic (EM) signature. Determination of EM signature was performed using a sensor that applies electromagnetic fields in the MHz regime to selectively electromanipulate cells with dielectrophoresis (DEP) and allows the monitoring of the induced cell motion generated by the field. By scanning the frequency range of interest, the cell DEP signature and the cross over frequency (frequency for which the DEP force becomes null) were identified. We found that CD133+ and CD133- cell display a significantly different crossover frequency. In particular, CD133+ cells are characterized by a lower cross over frequency than both CD133- and total population. This data suggest a non obvious correlation between crossover frequency and CSCs phenotype which would be potentially exploited to set up a label free system able to efficiently identify and physically separate subpopulation of cells enriched for CSC characteristics.
Citation Format: Roberta Bortolozzi, Elena Mariotto, Elena Rampazzo, Elena Porcù, Sofiane Saada, Thomas Provent, Fabrice Lalloué, Arnaud Pothier, Giampietro Viola, Luca Persano. Dielectric characterization of glioblastoma cancer stem cells [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics; 2019 Oct 26-30; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2019;18(12 Suppl):Abstract nr A058. doi:10.1158/1535-7163.TARG-19-A058