How are cells killed by radiation?
Radiation-induced damage leads to cell death by two mechanisms: apoptosis (or programmed cell death), an active process of cellular suicide, and necrosis, a process generally regarded as passive, which, in the case of radiation injury results from passage through mitosis of cells containing unrepaired DNA breaks and …
How does radiation affect cell migration?
Radiation promotes the release of cytokines and growth factors through the induction of a damage response [54]. Secreted by tumor, immune, or normal cells, many of these cytokines are involved in promoting tumor cell migration, invasion, and metastasis following radiotherapy.
How does radiation damage DNA cells?
Ionizing radiation directly affects DNA structure by inducing DNA breaks, particularly, DSBs. Secondary effects are the generation of reactive oxygen species (ROS) that oxidize proteins and lipids, and also induce several damages to DNA, like generation of abasic sites and single strand breaks (SSB).
Does radiation induce apoptosis?
Mitotic catastrophe (a pathway preceding cell death that happens in mitosis or as a consequence of aberrant mitotic progression) is the primary context of radiation-induced cell death in solid cancers, although in a small subset of cancers such as haematopoietic malignancies, radiation results in immediate interphase …
What theory explains why radiation can cause death in some cells?
This theory is based on the following assumptions: ionizing radiation induces cellular “sublesions”, which are proportional to the radiation dose; the interaction between two sublesions can produce a “lesion”, which has a certain fixed probability to lead to cell death.
What is the mechanism of action of radiotherapy?
Mechanism of action. Radiation therapy works by damaging the DNA of cancerous cells. This DNA damage is caused by one of two types of energy, photon or charged particle. This damage is either direct or indirect ionization of the atoms which make up the DNA chain.
What is the mechanism of radiation therapy?
Radiation therapy uses particles or waves moving at a high frequency to target the DNA of cells in the body and change the way they are able to replicate. If the DNA required for mitosis and replication is damaged, the cells are unable to replicate as usual and the growth of a cancerous tumor is inhibited.
How does radiation affect cells and tissues?
High doses tend to kill cells, while low doses tend to damage or change them. High doses can kill so many cells that tissues and organs are damaged. This in turn may cause a rapid whole body response often called the Acute Radiation Syndrome (ARS).
What is a radiation induced mutation?
Glossary Term. Radiation Induced Mutation. MGI Glossary. Definition. A mutation induced by irradiation, in mouse usually gamma-ray or X-ray.
What is the form of DNA damage produced by radiation?
DNA double-strand breaks constitute the most dangerous type of DNA damage induced by ionising radiation (IR). Accordingly, the resistance of cells to IR is modulated by three intimately related cellular processes: DNA repair, recombination, and replication.
How are cell death mechanisms induced in radiation therapy?
The efficiency of radiotherapy and radioimmunotherapy has much to gain by understanding the cell death mechanisms that are induced in tumor cells following irradiation. Strategies to use specific inhibitors that will manipulate key molecules in these pathways in combination with radiation might potentiate therapy and enhance tumor cell kill.
What are the molecular mechanisms of radiation induced senescence?
Radiation-induced senescence is triggered by DNA damage and the induction of the p53 and pRb pathways causing cell cycle block, but other factors including oxidative stress may also be relevant triggers in the irradiation context ( Sabin and Anderson, 2011; Li et al., 2018 ).
How is DNA damage induced in radiation cells?
Radiation-induced DNA damage is sensed by the kinases ataxia-telangiectasia mutated (ATM) and ataxia-telangiectasia and Rad3-related protein (ATR), which activate downstream proteins to initiate the DNA damage response (reviewed in Maier et al., 2016 ).
What happens to the cell cycle after irradiation?
It has become obvious in the last few years that inhibition of the proliferative capacity of malignant cells following irradiation, especially with solid tumors, can occur via alternative cell death modalities or permanent cell cycle arrests, i.e., senescence.