New method could double efficacy of radiation therapy

Cancer radiation therapy capitalizes on radiation's ability to kill cells by causing double-strand breaks in DNA. But, because varying levels of radiation are essentially everywhere – food, air, and the ground – all cells, including cancer cells, have internal mechanisms to prevent the lethal breakage. Scientists are targeting these natural defense mechanisms by packaging a piece of an antibody against one of them with folate. Many cancers, including the lung cancer cells used in the latest study, have large numbers of folate receptors. So, the cancer cells get a disproportionate share of the antibody/folate package. Once inside the cell the antibody attacks the regulatory region of the DNA-dependent protein kinase, an enzyme essential to DNA repair, making the cell more susceptible to radiation. Scientists believe this method could double the efficacy and reduce the side effects of cancer radiation therapy.