TY - JOUR AU - Chen, Xueying AU - Kong, Xiangbo AU - Zhang, Zhaoqiang AU - Chen, Wei AU - Chen, Jieyu AU - Li, Huanyang AU - Cao, Wanting AU - Ge, Yaping AU - Fang, Silian PY - 2014 TI - Alpha-2-macroglobulin as a radioprotective agent: a review JF - Chinese Journal of Cancer Research; Vol 26, No 5 (October 31, 2014): Chinese Journal of Cancer Research Y2 - 2014 KW - N2 - Radiation is an important modality in cancer treatment, and eighty percent of cancer patients need radiotherapy at some point during their clinical management. However, radiation-induced damage to normal tissues restricts the therapeutic doses of radiation that can be delivered to tumours and thereby limits the effectiveness of the treatment. The use of radioprotectors represents an obvious strategy to obtain better tumour control using a higher dose in radiotherapy. However, most of the synthetic radioprotective compounds studied have shown inadequate clinical efficacy owing to their inherent toxicity and high cost. Hence, the development of radioprotective agents with lower toxicity and an extended window of protection has attracted a great deal of attention, and the identification of alternative agents that are less toxic and highly effective is an absolute necessity. Recent studies have shown that alpha-2-macroglobulin (α 2 M) possesses radioprotective effects. α 2 M is a tetrameric, disulfide-rich plasma glycoprotein that functions as a non-selective inhibitor of different types of non-specific proteases and as a carrier of cytokines, growth factors, and hormones. α 2 M induces protein factors whose interplay underlies radioprotection, which supports the idea that α 2 M is the central effector of natural radioprotection in the rat. Pretreatment with α 2 M has also induced a significant reduction of irradiation-induced DNA damage and the complete restoration of liver and body weight. Mihailović Mirjana et al. concluded that the radioprotection provided by α 2 M was in part mediated through cytoprotection of new blood cells produced in the bone marrow; these authors also indicated that an important aspect of the radioprotective effect of amifostine was the result of the induction of the endogenous cytoprotective capability of α 2 M. The radioprotective effects of α 2 M are possibly due to antioxidant, anti-fibrosis, and anti-inflammatory functions, as well as the maintenance of homeostasis, and enhancement of the DNA repair and cell recovery processes. This review is the first to summarise the observations and elucidate the possible mechanisms responsible for the beneficial effects of α 2 M. The lacunae in the existing knowledge and directions for future research are also addressed. UR - https://cjcr.amegroups.org/article/view/4956