Apoptosis assays are a widely used application in High Content Analysis because of their central role in cancer research and immunology. There are two main pathways for the induction of apoptosis: the death receptor-mediated pathway and the mitochondrial pathway.

Induction of either pathway will result in the activation of caspases, a class of intracellular cysteine proteases which are considered to be the central components of the apoptotic response. 

Imaging based analysis of caspase activation, mitochondrial function and nuclear fragmentation are typical high content apoptosis assays. 

The figure above shows a schematic representation of two commonly analyzed apoptotic features in High Content Screening: nuclear fragmentation and caspase-3 activation upon apoptotic stimulus. The cells have been stained with a nuclear marker (red) and an antibody for caspase-3 (green) in various stages after treatment with an apoptosis inducing compound. From left to right: increasing dose of compound.