- Assessment of Annexin-V binding to externalised phosphatylserine on the cell membrane
- Assessment of increase in caspase 3/7 activity
- Cytotoxicity endpoints including proliferative and viability measures
- Component requirement: 10mg
- Turnaround: 2 weeks from commencement of testing
The term apoptosis is used to describe a specific pathway of programmed cell death or ‘suicide’ with a distinct morphological and biochemical signature involving the fragmentation of chromosomes. It is central to normal physiological function, with roles in cell turnover, the immune system, clearance of aberrant cells etc1. Disregulated apoptosis is found in many cancerous cells. Apoptosis is induced in normal cells exposed to genotoxins at doses where repair systems are overwhelmed.
Induction of apoptosis may be assessed early in compound screening in discovery and development, as a way to identify highly toxic drug candidates. It may also be used during later-stage compound safety profiling, as a follow up for positive results generated during other screening tests. For example, the impact of high cytotoxicity on the reliability of in vitro genotoxicity assessments has been well publicised, and this has resulted in new regulatory testing guidance, which limits cytotoxicity and reduces the incidence of misleading positives2, 3. Incorporation of cytotoxicity and apoptosis endpoints into in vitro genotoxicity test strategies can support mechanistic safety assessments by identifying compounds where a genotoxicity results might be misleading4.
References1Elmore, S. (2007). Apoptosis: A review of programmed cell death. Toxicologic Pathology 35, 495-516. 2Galloway, S. M. (2000) Cytotoxicity and chromosome aberrations in vitro: Experience in industry and the case for an upper limit on toxicity in the aberration assay. Environmental and Molecular Mutagenesis, 35(3), 191-201. 3Fellows, M. & O’Donovan, M. R. (2007) Cytotoxicity in cultured mammalian cells is a function of the method used to estimate it. Mutagenesis, 22(4), 275-280. 4Shi, J., Springer, S., Escobar, P. (2010) Coupling cytotoxicity biomarkers with DNA damage assessment in TK6 human lymphoblast cells. Mutation Research, 696: 167-178.