Different techniques for drug cytotoxicity evaluation on MCF-7 human breast cancer cell line

Contrasting results have been reported following the use of different in vitro techniques for the evaluation of drug cytotoxicity on cultured cell lines. Our interest focuses on the evaluation of drug cytotoxicity on a ER+ breast cancer cell line (MCF-7). The present study compares the effect of Doxorubicin using the following different techniques: a dye exclusion test; cell growth after treatment, expressed either as slope of cell growth curves or as the number of cells in treated cultures as a percentage of the number of cells in control cultures at different time intervals after treatment; a clonogenic assay in liquid medium. The dye exclusion assay failed to demonstrate drug-related killing of cells. Our data from the present study support the relative superiority of clonogenic assay compared to other methods. However, the occasional use of different methods could by-pass the limitations of this assay, and, depending on the specific experimental conditions, could lead to a better definition of drug cell killing.