Cell type-dependent cellular responses to radiation: Induction of apoptosis and mitotic catastrophe

Abstract

Although both UV and ionizing radiation are well known as DNA damage inducers, the cellular responses to each radiation are quite different. Regarding the type of cell death, UV causes a rapid cell death and ionizing radiation induces a delayed form of apoptosis. And most hematopoietic cells are known to be more sensitive to radiation than non-hematopoietic cells.
In order to know what makes these differences, Jurkat and HeLa cells were irradiated with either 15 Gy of γ-rays or 20 J/m² of UV (254 nm), both of which show a similar effect on cell killing, and incubated for various time intervals. In Jurkat cells, the induction of apoptosis caused by γ-rays was much slower than by UV. On the other hand, in HeLa cells, UV induced a delayed type of apoptosis and γ-rays mainly caused a reproductive cell death with the morphological appearance of mitotic catastrophe.