Certain prostate cancer cell lines are unable to repair DNA damage caused by "free radicals," according to scientists at the National Institute of Standards and Technology (NIST) and National Institutes of Health (NIH). This type of damage has been implicated before in the development of prostate cancer, but the new research, described in the March 25 online edition of Carcinogenesis, provides the first solid evidence that the normal repair process is altered in prostate cancer cells, possibly leading to a cascade of events that culminate in further DNA damage and cellular dysfunction.
Free radicals—highly reactive molecules generated by both normal metabolism and external sources such as chemicals and ionizing radiation—produce more than 30 different types of lesions in the nitrogen-containing compounds or "bases" of DNA. The damage is generally repaired in normal cells of young, healthy people. The NIH/NIST study examined four types of lesions in DNA from both cell nuclei and mitochondria, the energy factories of cells. The scientists found that prostate cancer cells unexposed to ionizing radiation had high levels of free radical damage and defective repair mechanisms. They also found that, after exposure to ionizing radiation and a repair period, prostate cancer cells exhibited elevated levels of free radical damage and reduced removal of lesions.