Molecular study of DNA radioprotection by thiols

Polyamines (PA) are natural components of mammalian cells, essential for growth processes. Since a decrease of the cellular level of PA increases the effect of radiotherapy on tumour cells, we have supposed that PA may act as DNA radioprotectors. The search of non-toxic agents that protect specifically normal cells led to the discovery of the agent WR-2721 used now in cancer cancer therapy under the name Ethyol (Amifostine) and of the agent WR-151327. Both have a chemical structure close to that of natural PA. The main radioprotective metabolites of these agents are the thiols WR>61065 and WR-151326. We have compared here here the protective effects of these thiols to those of another simpler thiol, the cysteamine, and of a related PA, the putrescine, on the number and location of fast neutrons-induced DNA strand breaks. (authors)