Abstract 4300: Comparative assessment of cell viability and motility kinetics by novel real-time technology and classic endpoint assays
Authors: Limame Ridha , Wouters An , Pauwels Bea , Fransen Erik , Peeters Marc , Pauwels Patrick , Wever Olivier De , Lardon Filip 
Published: August 2012

Abstract
Background Elucidation of biological mechanisms underlying deregulated proliferation and motility of cancer cells and identification of potential therapeutic targets require accurate cell-based monitoring. The xCELLigence Real Time Cell Analysis (RTCA) technology (Roche Applied Science) constitutes a non-invasive and label-free approach to assess cell viability and motility in real time, hereby countering key features of classic label-based endpoint detection methods. Here we show results of in vitro detection of cell viability and migration on 2 cancer cell lines using xCELLigence RTCA DP and correlate these with data obtained from parallel experiments carried out using established assessment methods for each process. Methods and results Kinetic viability and migration measurements were carried out on the MDA-MB-231 (breast cancer) and A549 (lung cancer) cell lines using the xCELLigence RTCA DP instrument. Cell viability was assessed during 10 days of incubation using modified 16-well plates (E-plate) containing microelectrodes at the well bottoms for impedance-based detection of attachment, spreading and proliferation, expressed as a Cell Index (CI) value. Cell migration was measured during 38 hours using 16-well plates (CIM16-plate) consisting of an upper and a lower chamber separated by a microporous membrane equipped with a similar detection system at the bottom side. The Sulforhodamine B (SRB) assay and a 24-well Transwell system served as reference tools to assess viability and migratory kinetics. Viability was estimated by optical density (OD) reading (540 nm) of solubilized cells that were fixed and stained with SRB at a rate of 1 plate per day. Good correlations were observed between SRB and RTCA CI for 5x103 and 104 MDA-MB-231 cells/mL (Spearman's ≤ = 0.79 and 0.84 resp) and similar doubling times (p = 0.459). The experimental Transwell design allowed dynamic quantitation of cancer cell migration by fixing and staining of the insert membranes in methanol and crystal violet in duplicates at 10 time points during a 24 hour-incubation. Pixel area quantitation showed strong correlation with xCELLigence CI (Spearman's ≤ = 0.90 for both cell lines). However, OD measurements (590 nm) correlated even stronger with CI (Spearman's ≤ = 0.96 and 1.00 for MDA-MB-231 and A549). Moreover, analysis of random migration indicated a significant difference between RTCA CI and area / OD (p &lt; 0.001) implying reduced detection limits of the xCELLigence system. Conclusions The similarity between observations as performed with conventional approaches and xCELLigence makes both methods interchangeable. Added with results indicating reduced detection limits, xCELLigence provides an accurate detection platform for high-throughput kinetic screenings and for determination of time-dependent cell proliferation and motility dynamics.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 4300. doi:1538-7445.AM2012-4300