Life is complicated. So is death. And when the cells in your multiwell plate die after compound treatment, it’s not enough to know that they died. You need to know how they died: apoptosis or necrosis? Or, have you really just reduced viability, rather than induced death? Is the cytotoxicity you see dose-dependent? If you look earlier during drug treatment of your cells, do you see markers of apoptosis? If you wait longer, do you observe necrosis? If you reduce the dosage of your test compound, is it still cytotoxic?
In vitro cytotoxicity testing, once restricted to large pharmaceutical labs, is now becoming commonplace in academic labs as more researchers enter the arena of chemical genomics. Many new assays have been developed to measure cellular stress, specific signaling events, cell viability, and cytotoxicity. However, only some of these assays can be performed in the wells of a multiwell plate; and only certain ones of those can be multiplexed to gather data on multiple parameters from a single sample well.
A paper recently published by Niles et al. in Current Chemical Genomics discusses in vitro cytotoxicity testing and the assays that are available for researchers doing these kinds of studies. The authors discuss the different types of assays available (cytotoxicity, viability, redox potential, LDH, protease, etc.), what each assay endpoint can reveal, and the advantages and disadvantages of each assay type.
For researchers designing in vitro cytotoxicity testing studies, this review article provides abundant information about reagents, considerations, and caveats.
Niles, A.L., Moravec, R.A. and Riss, T.L. (2009) In vitro viability and cytotoxicity testing and same-well multi-parametric combinations for high-throughput screening. Current Chemical Genomics 3, 33-41.