In Vitro Cell Death Determination for Drug Discovery: A Landscape Review of Real Issues

Méry, Benoite; Guy, Jean-Baptiste; Vallard, Alexis; Espenel, Sophie; Ardail, Dominique; Rodriguez-Lafrasse, Claire; Rancoule, Chloé; Magné, Nicolas

Understanding every molecular signaling pathway involved in cell death and elaborating potential drugs that could interfere with these specific mechanisms are the main framework for progress. An insight into cell death processes is a condition sine qua non to develop more effective and specific therapeutic approaches. Several in vitro methods for assessing cell death exist and studies largely recommend not using a single method, for having both quantitative and qualitative data. Cells can die by different modes, which are sometimes difficult to distinguish, and it is thereby essential that the measurement of cell death involves complementary methodologies. Indeed, the main drawback of apoptosis-specific and necrosis-specific assays is that neither of these assays can provide unequivocal information on the occurrence of one specific cell death modality compared with the other. Similarly, reliable method for the detection of autophagy has not yet been developed. Another important point concerns the timing of experimentation as apoptosis often occurs very quickly, whereas necrosis is much slower; thus, the use of additional clonogenicity and viability assays is necessary so as to correctly assess cell death pathways. 21 Finally, progress has been made concerning cell deathbased HTS approaches leading to the identification of promising compounds, and the combination of increasingly sophisticated microscopic methods should accelerate the discovery of cell death modulatory drugs.