94P Comparison of A Novel, Label-Free, and Real-Time cell Based System (Xcelligence) With a Conventional Viability Assay (Xtt) to Determine the Anti-Proliferative Effect of At-101 in Human Breast Cancer Cells

Abstract

ABSTRACT Introduction Viability tests are the main cornerstones of in vitro studies. Several approaches have been developed for this aim. However, most of these approaches are end point, in vitro based assays that require substantial reagent optimization, and are inadequate in providing information on its effective activity intracellularly. Aim Anti-proliferative effects of AT-101, a natural polyphenolic compound extracted from the cotton plant, on breast (MCF-7 and MDA-MB-231) were investigated by comparing xCELLigence system with conventional XTT viability assay. Method 1x104 cells were cultured in 96 microelectronic well plates for 24 hours. Then, different concentrations of AT-101 (0.5 20 µM) were added to each microwell. The evolution of the cell culture was assessed every 60 minutes during the pretreatment period, at 96 hours after drug addition, and every 60 minutes from 1 to 96 hours. Simultaneously, we performed a 2,3-bis (2-methoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino) carbonyl]-2H-tetrazolium hydroxide (XTT) assay. The RTCA results were expressed as a normalized cellular index (NCI). Result IC50 concentrations were determined based on the dose response curves derived by xCELLigence system and XTT assays. IC50 values were determined as 8.6 µM, 6.9 µM in xCELLigence measurements in MDA-MB-231 and MCF-7 cells, respectively. Whereas, in XTT viability assay, IC50 values were 10 µM, 9.2 µM, respectively. The xCELLigence system was slightly more sensitive than the XTT assay in the evaluation of AT-101 viability in cells. Moreover, the xCELLigence system showed less intra-assay variability, as compared to the XTT. Discussion Compared to conventional end-point cell-based assays, dynamic monitoring of cell response is one of the advantages of the xCELLigence system which is impossible to achieve by the currently established end-point assays as in XTT viability assay. Therefore, the xCELLigence system can be used as a rapid monitoring tool for cellular viability and be applied in toxicity testing of cytotoxic agents using in vitro cell cultures. Disclosure All authors have declared no conflicts of interest.