Modes of Cell Death and Survival Assays

Abstract

There are many ways that normal and tumor cells can die from radiation injury. Extensive DNA damage may result in mitotic catastrophe or senescence, or necrosis with corresponding inflammation. Alternatively, some cell types may undergo apoptosis, an orderly “programmed” dismantling of the cell that does not involve the inflammatory process. However, other modes of death, such as necroptosis and autophagy (and even submodes) have been identified, with their relevance to the overall radiation response being an active area of investigation. It should be noted that there is no general response to radiation by all cells, since mode of death may be dose- and cell-type dependent. Cell survival under various conditions can be measured using in vitro and in vivo assays. Different assays are suitable for measuring different endpoints in tumors and normal tissues. However, clonogenic cell survival is generally regarded as the gold standard for measuring loss of reproductive integrity after irradiation, regardless of the mode of death.