title: Rescue effects: irradiated cells helped by unirradiated bystander cells.
abstract: The rescue effect describes the phenomenon where irradiated cells or organisms derive benefits from the feedback signals sent from the bystander unirradiated cells or organisms. An example of the benefit is the mitigation of radiation-induced DNA damages in the irradiated cells. The rescue effect can compromise the efficacy of radioimmunotherapy (RIT) (and actually all radiotherapy). In this paper, the discovery and subsequent confirmation studies on the rescue effect were reviewed. The mechanisms and the chemical messengers responsible for the rescue effect studied to date were summarized. The rescue effect between irradiated and bystander unirradiated zebrafish embryos in vivo sharing the same medium was also described. In the discussion section, the mechanism proposed for the rescue effect involving activation of the nuclear factor κB (NF-κB) pathway was scrutinized. This mechanism could explain the promotion of cellular survival and correct repair of DNA damage, dependence on cyclic adenosine monophosphate (cAMP) and modulation of intracellular reactive oxygen species (ROS) level in irradiated cells. Exploitation of the NF-κB pathway to improve the effectiveness of RIT was proposed. Finally, the possibility of using zebrafish embryos as the model to study the efficacy of RIT in treating solid tumors was also discussed.
authors.affiliation: Department of Physics and Materials Science, City University of Hong Kong, Kowloon, Hong Kong. roykk.lam@my.cityu.edu.hk.
authors.forename: R K K
authors.initials: RK
authors.lastname: Lam
authors.affiliation: Department of Physics and Materials Science, City University of Hong Kong, Kowloon, Hong Kong. yikifung2-c@my.cityu.edu.hk.
authors.forename: Y K
authors.initials: YK
authors.lastname: Fung
authors.affiliation: Center of Medical Physics and Technology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China. hanw@hfcas.ac.cn.
authors.forename: W
authors.initials: W
authors.lastname: Han
authors.affiliation: Department of Physics and Materials Science, City University of Hong Kong, Kowloon, Hong Kong. peter.yu@cityu.edu.hk.
authors.forename: K N
authors.initials: KN
authors.lastname: Yu
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000528:radiation effects; D024201:Bystander Effect / Q000502:physiology*; D000242:Cyclic AMP / Q000378:metabolism; D004625:Embryo, Nonmammalian / Q000528:radiation effects; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism; D016328:NF-kappa B / Q000378:metabolism; D011839:Radiation, Ionizing; D017382:Reactive Oxygen Species / Q000378:metabolism; D015027:Zebrafish / Q000254:growth & development
chemical_list: D047908:Intracellular Signaling Peptides and Proteins; D016328:NF-kappa B; D017382:Reactive Oxygen Species; D000242:Cyclic AMP