xCELLigence system for real-time label-free monitoring of growth and viability of cell lines from hematological malignancies

Abstract

The xCELLigence system is a new technological approach that allows the real-time cell analysis of adherent tumor cells. To date, xCELLigence has not been able to monitor the growth or cytotoxicity of nonadherent cells derived from hematological malignancies. The basis of its technology relies on the use of culture plates with gold microelectrodes located in their base. We have adapted the methodology described by others to xCELLigence, based on the pre-coating of the cell culture surface with specific substrates, some of which are known to facilitate cell adhesion in the extracellular matrix. Pre-coating of the culture plates with fibronectin, compared to laminin, collagen, or gelatin, significantly induced the adhesion of most of the leukemia/lymphoma cells assayed (Jurkat, L1236, KMH2, and K562). With a fibronectin substrate, nonadherent cells deposited in a monolayer configuration, and consequently, the cell growth and viability were robustly monitored. We further demonstrate the feasibility of xCELLigence for the real-time monitoring of the cytotoxic properties of several antineoplastic agents. In order to validate this technology, the data obtained through real-time cell analysis was compared with that obtained from using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide method. This provides an excellent label-free tool for the screening of drug efficacy in nonadherent cells and discriminates optimal time points for further molecular analysis of cellular events associated with treatments, reducing both time and costs.

Whole-cell biosensor for label-free detection of GPCR-mediated drug responses in personal cell lines

“…Collageninteracting integrins are thus likely not present in LCLs, while fibronectin-specific integrins are. Furthermore, the findings agree with Martinez-Serra et al (2014) who showed that cells from hematological malignancies, including the leukemia lymphoblast cell line K562, attached more efficiently to fibronectin than to collagen, laminin or gelatin.…”

“…It is well known that the cell density and distribution on the electrodes can significantly influence impedance and experimental readout (Fang, 2011;Rocheville et al, 2013;Yu et al, 2006). In previous cases, fibronectin was often used to achieve cell adherence combined with increased cell densities with an optimal range of 60,000 to 45,000 cells/well (Gedge, 2010;Martinez-Serra et al, 2014;Obr et al, 2013;Schroder et al, 2011). Accordingly, we first tested various standard coating conditions and optimized cell density for impedance recordings in LCLs and found similar conditions to be optimal for LCLs.…”

“…Obr et al (2013) applied the technology to measure the effect of histone deacetylase inhibitors on hematopoietic cells. Martinez-Serra et al (2014) investigated the cytotoxic effect of antineoplastic agents on cells from hematological malignancies, which included the leukemia lymphoblast cell line K562. It is well known that the cell density and distribution on the electrodes can significantly influence impedance and experimental readout (Fang, 2011;Rocheville et al, 2013;Yu et al, 2006).…”

“…One disadvantage, however, is that the detection method of label-free assays generally requires cells to adhere to the detector surface at the bottom of the well (Rocheville et al, 2013;Yu et al, 2006) and unfortunately, LCLs are by nature non-adherent suspension cells (Avila-Carino et al, 1991). However, several reports have been published recently on the application of label-free technology to suspension cells, including various types of blood cells (Martinez-Serra et al, 2014;Schroder et al, 2011). To solve the above listed challenges we developed a methodology for a label-free, impedance-based whole-cell assay that allows characterization of GPCR signaling in LCLs despite their suspension cell nature.…”

Salinomycin efficiency assessment in non-tumor (HB4a) and tumor (MCF-7) human breast cells

“…This is possible because of gold microelectrodes coupled to the base of a 96-well culture plate called an EPlate. Those electrodes are connected to a computer that measures differences in impedance within an electrical circuit (Martinez-Serra et al 2014). The impedance reflects changes in adhesion or detachment of cells from the well, as well as changes in cell morphology (Roshan et al 2015).…”